Remote estimation over control area networks Aditya Mahajan McGill - - PowerPoint PPT Presentation

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Remote estimation over control area networks Aditya Mahajan McGill - - PowerPoint PPT Presentation

Remote estimation over control area networks Aditya Mahajan McGill University NetV Workshop, VTC 2017 24 Sep 2017 The road to self-driving cars . . . Car can handle dynamic driving tasks but still need human intervention Fully


slide-1
SLIDE 1

Remote estimation over control area networks

Aditya Mahajan

McGill University

NetV Workshop, VTC 2017 24 Sep 2017

slide-2
SLIDE 2

The road to self-driving cars . . .

Level 1

Control either speed or steering Cruise control Automatic breaking

Level 2

Control both speed or steering Automatic lane control (Tesla’s autopilot)

Level 3

Car can handle “dynamic driving tasks” but still need human intervention . . .

Level 4

Fully autonomous in certain situations . . .

Level 5

Fully autonomous in all situations . . .

slide-3
SLIDE 3

The road to self-driving cars . . .

Level 1

Control either speed or steering Cruise control Automatic breaking

Level 2

Control both speed or steering Automatic lane control (Tesla’s autopilot)

Level 3

Car can handle “dynamic driving tasks” but still need human intervention . . .

Level 4

Fully autonomous in certain situations . . .

Level 5

Fully autonomous in all situations . . .

These advances are driven by sophisticated algorithms that rely on measurements from multiple sensors

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SLIDE 4
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SLIDE 5

Communication between the sensors, controllers, and actuators takes place over the Control Area Network (CAN) As the number of sensors increase, it is critical to ensure that the information exchange is effjcient.

slide-6
SLIDE 6

Remote estimation over CAN–(Mahajan)

4

Background

slide-7
SLIDE 7

Remote estimation over CAN–(Mahajan)

4

Background

Arbitration in Control Area Network

slide-8
SLIDE 8

Remote estimation over CAN–(Mahajan)

4

Background

Arbitration in Control Area Network Arbitration in Control Area Network

Each data-frame consists of a 11 or 29 bit arbitrartion fjeld and payload.

slide-9
SLIDE 9

Remote estimation over CAN–(Mahajan)

4

Background

Arbitration in Control Area Network Arbitration in Control Area Network

Each data-frame consists of a 11 or 29 bit arbitrartion fjeld and payload.

Arbitration in Control Area Network

Each data-frame consists of a 11 or 29 bit arbitrartion fjeld and payload. When the CAN bus is idle, all nodes start transmitting at the same time. Bitwise transmission can be dominant (high voltage) or recessive (low voltage) If any node transmits at a dominant level, the voltage of the bus is high.

slide-10
SLIDE 10

Remote estimation over CAN–(Mahajan)

4

Background

Arbitration in Control Area Network Arbitration in Control Area Network

Each data-frame consists of a 11 or 29 bit arbitrartion fjeld and payload.

Arbitration in Control Area Network

Each data-frame consists of a 11 or 29 bit arbitrartion fjeld and payload. When the CAN bus is idle, all nodes start transmitting at the same time. Bitwise transmission can be dominant (high voltage) or recessive (low voltage) If any node transmits at a dominant level, the voltage of the bus is high.

Arbitration in Control Area Network

Each data-frame consists of a 11 or 29 bit arbitrartion fjeld and payload. When the CAN bus is idle, all nodes start transmitting at the same time. Bitwise transmission can be dominant (high voltage) or recessive (low voltage) If any node transmits at a dominant level, the voltage of the bus is high. Nodes monitor the voltage on the bus. If a node transmitting at a recessive level detects a dominant voltage on the bus, it immediately quits transmitting.

slide-11
SLIDE 11

Remote estimation over CAN–(Mahajan)

4

Background

Arbitration in Control Area Network Arbitration in Control Area Network

Each data-frame consists of a 11 or 29 bit arbitrartion fjeld and payload.

Arbitration in Control Area Network

Each data-frame consists of a 11 or 29 bit arbitrartion fjeld and payload. When the CAN bus is idle, all nodes start transmitting at the same time. Bitwise transmission can be dominant (high voltage) or recessive (low voltage) If any node transmits at a dominant level, the voltage of the bus is high.

Arbitration in Control Area Network

Each data-frame consists of a 11 or 29 bit arbitrartion fjeld and payload. When the CAN bus is idle, all nodes start transmitting at the same time. Bitwise transmission can be dominant (high voltage) or recessive (low voltage) If any node transmits at a dominant level, the voltage of the bus is high. Nodes monitor the voltage on the bus. If a node transmitting at a recessive level detects a dominant voltage on the bus, it immediately quits transmitting.

Arbitration in Control Area Network

Each data-frame consists of a 11 or 29 bit arbitrartion fjeld and payload. When the CAN bus is idle, all nodes start transmitting at the same time. Bitwise transmission can be dominant (high voltage) or recessive (low voltage) If any node transmits at a dominant level, the voltage of the bus is high. Nodes monitor the voltage on the bus. If a node transmitting at a recessive level detects a dominant voltage on the bus, it immediately quits transmitting.

Scheduling sensor measurements is different from scheduling data packets

slide-12
SLIDE 12

Remote estimation over CAN–(Mahajan)

4

Background

Arbitration in Control Area Network Arbitration in Control Area Network

Each data-frame consists of a 11 or 29 bit arbitrartion fjeld and payload.

Arbitration in Control Area Network

Each data-frame consists of a 11 or 29 bit arbitrartion fjeld and payload. When the CAN bus is idle, all nodes start transmitting at the same time. Bitwise transmission can be dominant (high voltage) or recessive (low voltage) If any node transmits at a dominant level, the voltage of the bus is high.

Arbitration in Control Area Network

Each data-frame consists of a 11 or 29 bit arbitrartion fjeld and payload. When the CAN bus is idle, all nodes start transmitting at the same time. Bitwise transmission can be dominant (high voltage) or recessive (low voltage) If any node transmits at a dominant level, the voltage of the bus is high. Nodes monitor the voltage on the bus. If a node transmitting at a recessive level detects a dominant voltage on the bus, it immediately quits transmitting.

Arbitration in Control Area Network

Each data-frame consists of a 11 or 29 bit arbitrartion fjeld and payload. When the CAN bus is idle, all nodes start transmitting at the same time. Bitwise transmission can be dominant (high voltage) or recessive (low voltage) If any node transmits at a dominant level, the voltage of the bus is high. Nodes monitor the voltage on the bus. If a node transmitting at a recessive level detects a dominant voltage on the bus, it immediately quits transmitting.

Scheduling sensor measurements is different from scheduling data packets Arbitration in Control Area Network

Each data-frame consists of a 11 or 29 bit arbitrartion fjeld and payload. When the CAN bus is idle, all nodes start transmitting at the same time. Bitwise transmission can be dominant (high voltage) or recessive (low voltage) If any node transmits at a dominant level, the voltage of the bus is high. Nodes monitor the voltage on the bus. If a node transmitting at a recessive level detects a dominant voltage on the bus, it immediately quits transmitting.

Scheduling sensor measurements is different from scheduling data packets

Suppose a sensor does not get access to the channel.

slide-13
SLIDE 13

Remote estimation over CAN–(Mahajan)

4

Background

Arbitration in Control Area Network Arbitration in Control Area Network

Each data-frame consists of a 11 or 29 bit arbitrartion fjeld and payload.

Arbitration in Control Area Network

Each data-frame consists of a 11 or 29 bit arbitrartion fjeld and payload. When the CAN bus is idle, all nodes start transmitting at the same time. Bitwise transmission can be dominant (high voltage) or recessive (low voltage) If any node transmits at a dominant level, the voltage of the bus is high.

Arbitration in Control Area Network

Each data-frame consists of a 11 or 29 bit arbitrartion fjeld and payload. When the CAN bus is idle, all nodes start transmitting at the same time. Bitwise transmission can be dominant (high voltage) or recessive (low voltage) If any node transmits at a dominant level, the voltage of the bus is high. Nodes monitor the voltage on the bus. If a node transmitting at a recessive level detects a dominant voltage on the bus, it immediately quits transmitting.

Arbitration in Control Area Network

Each data-frame consists of a 11 or 29 bit arbitrartion fjeld and payload. When the CAN bus is idle, all nodes start transmitting at the same time. Bitwise transmission can be dominant (high voltage) or recessive (low voltage) If any node transmits at a dominant level, the voltage of the bus is high. Nodes monitor the voltage on the bus. If a node transmitting at a recessive level detects a dominant voltage on the bus, it immediately quits transmitting.

Scheduling sensor measurements is different from scheduling data packets Arbitration in Control Area Network

Each data-frame consists of a 11 or 29 bit arbitrartion fjeld and payload. When the CAN bus is idle, all nodes start transmitting at the same time. Bitwise transmission can be dominant (high voltage) or recessive (low voltage) If any node transmits at a dominant level, the voltage of the bus is high. Nodes monitor the voltage on the bus. If a node transmitting at a recessive level detects a dominant voltage on the bus, it immediately quits transmitting.

Scheduling sensor measurements is different from scheduling data packets

Suppose a sensor does not get access to the channel.

Arbitration in Control Area Network

Each data-frame consists of a 11 or 29 bit arbitrartion fjeld and payload. When the CAN bus is idle, all nodes start transmitting at the same time. Bitwise transmission can be dominant (high voltage) or recessive (low voltage) If any node transmits at a dominant level, the voltage of the bus is high. Nodes monitor the voltage on the bus. If a node transmitting at a recessive level detects a dominant voltage on the bus, it immediately quits transmitting.

Scheduling sensor measurements is different from scheduling data packets

Suppose a sensor does not get access to the channel. Then, it should simply discard the previous measurement rather than bufgering it. Transmit fresh measurement at the next transmission instant.

slide-14
SLIDE 14

Remote estimation over CAN–(Mahajan)

6

Model and Problem Formulation

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SLIDE 15

Remote estimation over CAN–(Mahajan)

6

Model and Problem Formulation

System Model

Control Area Network Control Area Network ⋮ ⋮ Receiver 1 Receiver n Sensor 1 Sensor n (Z1

t, X1 t)

(Zn

t , Xn t )

Y1

t

Yn

t

ˆ X1

t

ˆ Xn

t

X1

t

Xn

t

slide-16
SLIDE 16

Remote estimation over CAN–(Mahajan)

6

Model and Problem Formulation

System Model

Control Area Network Control Area Network ⋮ ⋮ Receiver 1 Receiver n Sensor 1 Sensor n (Z1

t, X1 t)

(Zn

t , Xn t )

Y1

t

Yn

t

ˆ X1

t

ˆ Xn

t

X1

t

Xn

t

System Model

Sensors

n sensors indexed by N = {1, . . . , n}. Xi

t+1 = aiXi t + Wi t,

ai, Xi

t, Wi t ∈ ℝ,

Wi

t ∼ φi(⋅).

Assumptions

The observation processes across sensors are independent. The noise process is independent across time (and independent of initial state) The density φi(⋅) is even and unimodal.

Control Area Network Control Area Network ⋮ ⋮ Receiver 1 Receiver n Sensor 1 Sensor n (Z1

t, X1 t)

(Zn

t , Xn t )

Y1

t

Yn

t

ˆ X1

t

ˆ Xn

t

X1

t

Xn

t

slide-17
SLIDE 17

Remote estimation over CAN–(Mahajan)

6

Model and Problem Formulation

System Model

Control Area Network Control Area Network ⋮ ⋮ Receiver 1 Receiver n Sensor 1 Sensor n (Z1

t, X1 t)

(Zn

t , Xn t )

Y1

t

Yn

t

ˆ X1

t

ˆ Xn

t

X1

t

Xn

t

System Model

Sensors

n sensors indexed by N = {1, . . . , n}. Xi

t+1 = aiXi t + Wi t,

ai, Xi

t, Wi t ∈ ℝ,

Wi

t ∼ φi(⋅).

Assumptions

The observation processes across sensors are independent. The noise process is independent across time (and independent of initial state) The density φi(⋅) is even and unimodal.

Control Area Network Control Area Network ⋮ ⋮ Receiver 1 Receiver n Sensor 1 Sensor n (Z1

t, X1 t)

(Zn

t , Xn t )

Y1

t

Yn

t

ˆ X1

t

ˆ Xn

t

X1

t

Xn

t

System Model

Sensors

n sensors indexed by N = {1, . . . , n}. Xi

t+1 = aiXi t + Wi t,

ai, Xi

t, Wi t ∈ ℝ,

Wi

t ∼ φi(⋅).

Assumptions

The observation processes across sensors are independent. The noise process is independent across time (and independent of initial state) The density φi(⋅) is even and unimodal.

Network

Received packet Yi

t =

{ XI

t,

if sensor i has highest priority 𝔉,

  • therwise

Control Area Network Control Area Network ⋮ ⋮ Receiver 1 Receiver n Sensor 1 Sensor n (Z1

t, X1 t)

(Zn

t , Xn t )

Y1

t

Yn

t

ˆ X1

t

ˆ Xn

t

X1

t

Xn

t

slide-18
SLIDE 18

Remote estimation over CAN–(Mahajan)

6

Model and Problem Formulation

System Model

Control Area Network Control Area Network ⋮ ⋮ Receiver 1 Receiver n Sensor 1 Sensor n (Z1

t, X1 t)

(Zn

t , Xn t )

Y1

t

Yn

t

ˆ X1

t

ˆ Xn

t

X1

t

Xn

t

System Model

Sensors

n sensors indexed by N = {1, . . . , n}. Xi

t+1 = aiXi t + Wi t,

ai, Xi

t, Wi t ∈ ℝ,

Wi

t ∼ φi(⋅).

Assumptions

The observation processes across sensors are independent. The noise process is independent across time (and independent of initial state) The density φi(⋅) is even and unimodal.

Control Area Network Control Area Network ⋮ ⋮ Receiver 1 Receiver n Sensor 1 Sensor n (Z1

t, X1 t)

(Zn

t , Xn t )

Y1

t

Yn

t

ˆ X1

t

ˆ Xn

t

X1

t

Xn

t

System Model

Sensors

n sensors indexed by N = {1, . . . , n}. Xi

t+1 = aiXi t + Wi t,

ai, Xi

t, Wi t ∈ ℝ,

Wi

t ∼ φi(⋅).

Assumptions

The observation processes across sensors are independent. The noise process is independent across time (and independent of initial state) The density φi(⋅) is even and unimodal.

Network

Received packet Yi

t =

{ XI

t,

if sensor i has highest priority 𝔉,

  • therwise

Control Area Network Control Area Network ⋮ ⋮ Receiver 1 Receiver n Sensor 1 Sensor n (Z1

t, X1 t)

(Zn

t , Xn t )

Y1

t

Yn

t

ˆ X1

t

ˆ Xn

t

X1

t

Xn

t

System Model

Sensors

n sensors indexed by N = {1, . . . , n}. Xi

t+1 = aiXi t + Wi t,

ai, Xi

t, Wi t ∈ ℝ,

Wi

t ∼ φi(⋅).

Assumptions

The observation processes across sensors are independent. The noise process is independent across time (and independent of initial state) The density φi(⋅) is even and unimodal.

Network

Received packet Yi

t =

{ XI

t,

if sensor i has highest priority 𝔉,

  • therwise

Receivers

Estimate ˆ Xi

t =

{ Yi

t,

if Yi

t ≠ 𝔉

ai ˆ Xi

t−1,

if Yi

t = 𝔉

Distortion di(Xi

t − ˆ

Xi

t), where di(⋅) is an even and increasing function.

Control Area Network Control Area Network ⋮ ⋮ Receiver 1 Receiver n Sensor 1 Sensor n (Z1

t, X1 t)

(Zn

t , Xn t )

Y1

t

Yn

t

ˆ X1

t

ˆ Xn

t

X1

t

Xn

t

slide-19
SLIDE 19

Remote estimation over CAN–(Mahajan)

6

Model and Problem Formulation

System Model

Control Area Network Control Area Network ⋮ ⋮ Receiver 1 Receiver n Sensor 1 Sensor n (Z1

t, X1 t)

(Zn

t , Xn t )

Y1

t

Yn

t

ˆ X1

t

ˆ Xn

t

X1

t

Xn

t

System Model

Sensors

n sensors indexed by N = {1, . . . , n}. Xi

t+1 = aiXi t + Wi t,

ai, Xi

t, Wi t ∈ ℝ,

Wi

t ∼ φi(⋅).

Assumptions

The observation processes across sensors are independent. The noise process is independent across time (and independent of initial state) The density φi(⋅) is even and unimodal.

Control Area Network Control Area Network ⋮ ⋮ Receiver 1 Receiver n Sensor 1 Sensor n (Z1

t, X1 t)

(Zn

t , Xn t )

Y1

t

Yn

t

ˆ X1

t

ˆ Xn

t

X1

t

Xn

t

System Model

Sensors

n sensors indexed by N = {1, . . . , n}. Xi

t+1 = aiXi t + Wi t,

ai, Xi

t, Wi t ∈ ℝ,

Wi

t ∼ φi(⋅).

Assumptions

The observation processes across sensors are independent. The noise process is independent across time (and independent of initial state) The density φi(⋅) is even and unimodal.

Network

Received packet Yi

t =

{ XI

t,

if sensor i has highest priority 𝔉,

  • therwise

Control Area Network Control Area Network ⋮ ⋮ Receiver 1 Receiver n Sensor 1 Sensor n (Z1

t, X1 t)

(Zn

t , Xn t )

Y1

t

Yn

t

ˆ X1

t

ˆ Xn

t

X1

t

Xn

t

System Model

Sensors

n sensors indexed by N = {1, . . . , n}. Xi

t+1 = aiXi t + Wi t,

ai, Xi

t, Wi t ∈ ℝ,

Wi

t ∼ φi(⋅).

Assumptions

The observation processes across sensors are independent. The noise process is independent across time (and independent of initial state) The density φi(⋅) is even and unimodal.

Network

Received packet Yi

t =

{ XI

t,

if sensor i has highest priority 𝔉,

  • therwise

Receivers

Estimate ˆ Xi

t =

{ Yi

t,

if Yi

t ≠ 𝔉

ai ˆ Xi

t−1,

if Yi

t = 𝔉

Distortion di(Xi

t − ˆ

Xi

t), where di(⋅) is an even and increasing function.

Control Area Network Control Area Network ⋮ ⋮ Receiver 1 Receiver n Sensor 1 Sensor n (Z1

t, X1 t)

(Zn

t , Xn t )

Y1

t

Yn

t

ˆ X1

t

ˆ Xn

t

X1

t

Xn

t

Problem formulation

Information structure

St: Sensor with highest priority. All sensors observe St. Priority Assignment rule gi

t∶ (Xi 1:t, S1:t−1) ↦ Zi t.

St = arg max

i∈N Zi t

slide-20
SLIDE 20

Remote estimation over CAN–(Mahajan)

6

Model and Problem Formulation

System Model

Control Area Network Control Area Network ⋮ ⋮ Receiver 1 Receiver n Sensor 1 Sensor n (Z1

t, X1 t)

(Zn

t , Xn t )

Y1

t

Yn

t

ˆ X1

t

ˆ Xn

t

X1

t

Xn

t

System Model

Sensors

n sensors indexed by N = {1, . . . , n}. Xi

t+1 = aiXi t + Wi t,

ai, Xi

t, Wi t ∈ ℝ,

Wi

t ∼ φi(⋅).

Assumptions

The observation processes across sensors are independent. The noise process is independent across time (and independent of initial state) The density φi(⋅) is even and unimodal.

Control Area Network Control Area Network ⋮ ⋮ Receiver 1 Receiver n Sensor 1 Sensor n (Z1

t, X1 t)

(Zn

t , Xn t )

Y1

t

Yn

t

ˆ X1

t

ˆ Xn

t

X1

t

Xn

t

System Model

Sensors

n sensors indexed by N = {1, . . . , n}. Xi

t+1 = aiXi t + Wi t,

ai, Xi

t, Wi t ∈ ℝ,

Wi

t ∼ φi(⋅).

Assumptions

The observation processes across sensors are independent. The noise process is independent across time (and independent of initial state) The density φi(⋅) is even and unimodal.

Network

Received packet Yi

t =

{ XI

t,

if sensor i has highest priority 𝔉,

  • therwise

Control Area Network Control Area Network ⋮ ⋮ Receiver 1 Receiver n Sensor 1 Sensor n (Z1

t, X1 t)

(Zn

t , Xn t )

Y1

t

Yn

t

ˆ X1

t

ˆ Xn

t

X1

t

Xn

t

System Model

Sensors

n sensors indexed by N = {1, . . . , n}. Xi

t+1 = aiXi t + Wi t,

ai, Xi

t, Wi t ∈ ℝ,

Wi

t ∼ φi(⋅).

Assumptions

The observation processes across sensors are independent. The noise process is independent across time (and independent of initial state) The density φi(⋅) is even and unimodal.

Network

Received packet Yi

t =

{ XI

t,

if sensor i has highest priority 𝔉,

  • therwise

Receivers

Estimate ˆ Xi

t =

{ Yi

t,

if Yi

t ≠ 𝔉

ai ˆ Xi

t−1,

if Yi

t = 𝔉

Distortion di(Xi

t − ˆ

Xi

t), where di(⋅) is an even and increasing function.

Control Area Network Control Area Network ⋮ ⋮ Receiver 1 Receiver n Sensor 1 Sensor n (Z1

t, X1 t)

(Zn

t , Xn t )

Y1

t

Yn

t

ˆ X1

t

ˆ Xn

t

X1

t

Xn

t

Problem formulation

Information structure

St: Sensor with highest priority. All sensors observe St. Priority Assignment rule gi

t∶ (Xi 1:t, S1:t−1) ↦ Zi t.

St = arg max

i∈N Zi t

Problem formulation

Information structure

St: Sensor with highest priority. All sensors observe St. Priority Assignment rule gi

t∶ (Xi 1:t, S1:t−1) ↦ Zi t.

St = arg max

i∈N Zi t

Objective

min lim

T→∞

1 T 𝔽 [

T−1

t=0

i∈N i≠St

di(Xi

t − ˆ

Xi

t)

]

slide-21
SLIDE 21

Remote estimation over CAN–(Mahajan)

6

Model and Problem Formulation

System Model

Control Area Network Control Area Network ⋮ ⋮ Receiver 1 Receiver n Sensor 1 Sensor n (Z1

t, X1 t)

(Zn

t , Xn t )

Y1

t

Yn

t

ˆ X1

t

ˆ Xn

t

X1

t

Xn

t

System Model

Sensors

n sensors indexed by N = {1, . . . , n}. Xi

t+1 = aiXi t + Wi t,

ai, Xi

t, Wi t ∈ ℝ,

Wi

t ∼ φi(⋅).

Assumptions

The observation processes across sensors are independent. The noise process is independent across time (and independent of initial state) The density φi(⋅) is even and unimodal.

Control Area Network Control Area Network ⋮ ⋮ Receiver 1 Receiver n Sensor 1 Sensor n (Z1

t, X1 t)

(Zn

t , Xn t )

Y1

t

Yn

t

ˆ X1

t

ˆ Xn

t

X1

t

Xn

t

System Model

Sensors

n sensors indexed by N = {1, . . . , n}. Xi

t+1 = aiXi t + Wi t,

ai, Xi

t, Wi t ∈ ℝ,

Wi

t ∼ φi(⋅).

Assumptions

The observation processes across sensors are independent. The noise process is independent across time (and independent of initial state) The density φi(⋅) is even and unimodal.

Network

Received packet Yi

t =

{ XI

t,

if sensor i has highest priority 𝔉,

  • therwise

Control Area Network Control Area Network ⋮ ⋮ Receiver 1 Receiver n Sensor 1 Sensor n (Z1

t, X1 t)

(Zn

t , Xn t )

Y1

t

Yn

t

ˆ X1

t

ˆ Xn

t

X1

t

Xn

t

System Model

Sensors

n sensors indexed by N = {1, . . . , n}. Xi

t+1 = aiXi t + Wi t,

ai, Xi

t, Wi t ∈ ℝ,

Wi

t ∼ φi(⋅).

Assumptions

The observation processes across sensors are independent. The noise process is independent across time (and independent of initial state) The density φi(⋅) is even and unimodal.

Network

Received packet Yi

t =

{ XI

t,

if sensor i has highest priority 𝔉,

  • therwise

Receivers

Estimate ˆ Xi

t =

{ Yi

t,

if Yi

t ≠ 𝔉

ai ˆ Xi

t−1,

if Yi

t = 𝔉

Distortion di(Xi

t − ˆ

Xi

t), where di(⋅) is an even and increasing function.

Control Area Network Control Area Network ⋮ ⋮ Receiver 1 Receiver n Sensor 1 Sensor n (Z1

t, X1 t)

(Zn

t , Xn t )

Y1

t

Yn

t

ˆ X1

t

ˆ Xn

t

X1

t

Xn

t

Problem formulation

Information structure

St: Sensor with highest priority. All sensors observe St. Priority Assignment rule gi

t∶ (Xi 1:t, S1:t−1) ↦ Zi t.

St = arg max

i∈N Zi t

Problem formulation

Information structure

St: Sensor with highest priority. All sensors observe St. Priority Assignment rule gi

t∶ (Xi 1:t, S1:t−1) ↦ Zi t.

St = arg max

i∈N Zi t

Objective

min lim

T→∞

1 T 𝔽 [

T−1

t=0

i∈N i≠St

di(Xi

t − ˆ

Xi

t)

]

Problem formulation

Information structure

St: Sensor with highest priority. All sensors observe St. Priority Assignment rule gi

t∶ (Xi 1:t, S1:t−1) ↦ Zi t.

St = arg max

i∈N Zi t

Objective

min lim

T→∞

1 T 𝔽 [

T−1

t=0

i∈N i≠St

di(Xi

t − ˆ

Xi

t)

]

Salient Features

Decentralized stochastic control problem. Finding optimal solution is notoriously diffjcult. Use a heuristic policy instead. Motivated by value of information in economics.

slide-22
SLIDE 22

Remote estimation over CAN–(Mahajan)

9

What is Value of Information?

slide-23
SLIDE 23

Remote estimation over CAN–(Mahajan)

9

What is Value of Information?

A change of variables

Error process

Defjne Ei

0 = Xi 0 and for t ≥ 0,

Ei

t+1 =

{ Wi

t,

if St = i aiEi

t + Wi t

if St ≠ i

slide-24
SLIDE 24

Remote estimation over CAN–(Mahajan)

9

What is Value of Information?

A change of variables

Error process

Defjne Ei

0 = Xi 0 and for t ≥ 0,

Ei

t+1 =

{ Wi

t,

if St = i aiEi

t + Wi t

if St ≠ i

A change of variables

Error process

Defjne Ei

0 = Xi 0 and for t ≥ 0,

Ei

t+1 =

{ Wi

t,

if St = i aiEi

t + Wi t

if St ≠ i Called the error process because when St ≠ i, Xt − ˆ Xi

t = Ei

  • t. Thus, total estimation

error can be written as

min lim

T→∞

1 T 𝔽 [

T−1

t=0

i∈N i≠St

di(Ei

t)

]

slide-25
SLIDE 25

Remote estimation over CAN–(Mahajan)

9

What is Value of Information?

A change of variables

Error process

Defjne Ei

0 = Xi 0 and for t ≥ 0,

Ei

t+1 =

{ Wi

t,

if St = i aiEi

t + Wi t

if St ≠ i

A change of variables

Error process

Defjne Ei

0 = Xi 0 and for t ≥ 0,

Ei

t+1 =

{ Wi

t,

if St = i aiEi

t + Wi t

if St ≠ i Called the error process because when St ≠ i, Xt − ˆ Xi

t = Ei

  • t. Thus, total estimation

error can be written as

min lim

T→∞

1 T 𝔽 [

T−1

t=0

i∈N i≠St

di(Ei

t)

]

Defining the value of information

Value of Information (VOI)

The amount of money someone is willing to pay to access that information.

slide-26
SLIDE 26

Remote estimation over CAN–(Mahajan)

9

What is Value of Information?

A change of variables

Error process

Defjne Ei

0 = Xi 0 and for t ≥ 0,

Ei

t+1 =

{ Wi

t,

if St = i aiEi

t + Wi t

if St ≠ i

A change of variables

Error process

Defjne Ei

0 = Xi 0 and for t ≥ 0,

Ei

t+1 =

{ Wi

t,

if St = i aiEi

t + Wi t

if St ≠ i Called the error process because when St ≠ i, Xt − ˆ Xi

t = Ei

  • t. Thus, total estimation

error can be written as

min lim

T→∞

1 T 𝔽 [

T−1

t=0

i∈N i≠St

di(Ei

t)

]

Defining the value of information

Value of Information (VOI)

The amount of money someone is willing to pay to access that information.

Defining the value of information

Value of Information (VOI)

The amount of money someone is willing to pay to access that information.

VOI for remote estimation

Suppose that there is a single sensor, say i, and a dedicated communication channel is available. The sensor has to pay an access fee λi each time it uses the channel.

slide-27
SLIDE 27

Remote estimation over CAN–(Mahajan)

9

What is Value of Information?

A change of variables

Error process

Defjne Ei

0 = Xi 0 and for t ≥ 0,

Ei

t+1 =

{ Wi

t,

if St = i aiEi

t + Wi t

if St ≠ i

A change of variables

Error process

Defjne Ei

0 = Xi 0 and for t ≥ 0,

Ei

t+1 =

{ Wi

t,

if St = i aiEi

t + Wi t

if St ≠ i Called the error process because when St ≠ i, Xt − ˆ Xi

t = Ei

  • t. Thus, total estimation

error can be written as

min lim

T→∞

1 T 𝔽 [

T−1

t=0

i∈N i≠St

di(Ei

t)

]

Defining the value of information

Value of Information (VOI)

The amount of money someone is willing to pay to access that information.

Defining the value of information

Value of Information (VOI)

The amount of money someone is willing to pay to access that information.

VOI for remote estimation

Suppose that there is a single sensor, say i, and a dedicated communication channel is available. The sensor has to pay an access fee λi each time it uses the channel.

Defining the value of information

Value of Information (VOI)

The amount of money someone is willing to pay to access that information.

VOI for remote estimation

Suppose that there is a single sensor, say i, and a dedicated communication channel is available. The sensor has to pay an access fee λi each time it uses the channel. Let Ui

t ∈ {0, 1} denote the sensor’s decision.

Then, the error process is Ei

t+1 =

{ Wi

t,

if Ui

t = 1

aiEi

t + Wi t

if Ui

t = 0

slide-28
SLIDE 28

Remote estimation over CAN–(Mahajan)

9

What is Value of Information?

A change of variables

Error process

Defjne Ei

0 = Xi 0 and for t ≥ 0,

Ei

t+1 =

{ Wi

t,

if St = i aiEi

t + Wi t

if St ≠ i

A change of variables

Error process

Defjne Ei

0 = Xi 0 and for t ≥ 0,

Ei

t+1 =

{ Wi

t,

if St = i aiEi

t + Wi t

if St ≠ i Called the error process because when St ≠ i, Xt − ˆ Xi

t = Ei

  • t. Thus, total estimation

error can be written as

min lim

T→∞

1 T 𝔽 [

T−1

t=0

i∈N i≠St

di(Ei

t)

]

Defining the value of information

Value of Information (VOI)

The amount of money someone is willing to pay to access that information.

Defining the value of information

Value of Information (VOI)

The amount of money someone is willing to pay to access that information.

VOI for remote estimation

Suppose that there is a single sensor, say i, and a dedicated communication channel is available. The sensor has to pay an access fee λi each time it uses the channel.

Defining the value of information

Value of Information (VOI)

The amount of money someone is willing to pay to access that information.

VOI for remote estimation

Suppose that there is a single sensor, say i, and a dedicated communication channel is available. The sensor has to pay an access fee λi each time it uses the channel. Let Ui

t ∈ {0, 1} denote the sensor’s decision.

Then, the error process is Ei

t+1 =

{ Wi

t,

if Ui

t = 1

aiEi

t + Wi t

if Ui

t = 0

Defining the value of information

Value of Information (VOI)

The amount of money someone is willing to pay to access that information.

VOI for remote estimation

Suppose that there is a single sensor, say i, and a dedicated communication channel is available. The sensor has to pay an access fee λi each time it uses the channel. Let Ui

t ∈ {0, 1} denote the sensor’s decision.

Then, the error process is Ei

t+1 =

{ Wi

t,

if Ui

t = 1

aiEi

t + Wi t

if Ui

t = 0

Objective

min lim

T→∞

1 T 𝔽 [

T−1

t=0 [λiUi + (1 − Ui)di(Ei t)]]

slide-29
SLIDE 29

Remote estimation over CAN–(Mahajan)

9

What is Value of Information?

A change of variables

Error process

Defjne Ei

0 = Xi 0 and for t ≥ 0,

Ei

t+1 =

{ Wi

t,

if St = i aiEi

t + Wi t

if St ≠ i

A change of variables

Error process

Defjne Ei

0 = Xi 0 and for t ≥ 0,

Ei

t+1 =

{ Wi

t,

if St = i aiEi

t + Wi t

if St ≠ i Called the error process because when St ≠ i, Xt − ˆ Xi

t = Ei

  • t. Thus, total estimation

error can be written as

min lim

T→∞

1 T 𝔽 [

T−1

t=0

i∈N i≠St

di(Ei

t)

]

Defining the value of information

Value of Information (VOI)

The amount of money someone is willing to pay to access that information.

Defining the value of information

Value of Information (VOI)

The amount of money someone is willing to pay to access that information.

VOI for remote estimation

Suppose that there is a single sensor, say i, and a dedicated communication channel is available. The sensor has to pay an access fee λi each time it uses the channel.

Defining the value of information

Value of Information (VOI)

The amount of money someone is willing to pay to access that information.

VOI for remote estimation

Suppose that there is a single sensor, say i, and a dedicated communication channel is available. The sensor has to pay an access fee λi each time it uses the channel. Let Ui

t ∈ {0, 1} denote the sensor’s decision.

Then, the error process is Ei

t+1 =

{ Wi

t,

if Ui

t = 1

aiEi

t + Wi t

if Ui

t = 0

Defining the value of information

Value of Information (VOI)

The amount of money someone is willing to pay to access that information.

VOI for remote estimation

Suppose that there is a single sensor, say i, and a dedicated communication channel is available. The sensor has to pay an access fee λi each time it uses the channel. Let Ui

t ∈ {0, 1} denote the sensor’s decision.

Then, the error process is Ei

t+1 =

{ Wi

t,

if Ui

t = 1

aiEi

t + Wi t

if Ui

t = 0

Objective

min lim

T→∞

1 T 𝔽 [

T−1

t=0 [λiUi + (1 − Ui)di(Ei t)]]

Defining the value of information (cont.)

Optimal policy

The objective is a single agent multi-stage optimization problem. Optimal solution is given by dynamic programming.

slide-30
SLIDE 30

Remote estimation over CAN–(Mahajan)

9

What is Value of Information?

A change of variables

Error process

Defjne Ei

0 = Xi 0 and for t ≥ 0,

Ei

t+1 =

{ Wi

t,

if St = i aiEi

t + Wi t

if St ≠ i

A change of variables

Error process

Defjne Ei

0 = Xi 0 and for t ≥ 0,

Ei

t+1 =

{ Wi

t,

if St = i aiEi

t + Wi t

if St ≠ i Called the error process because when St ≠ i, Xt − ˆ Xi

t = Ei

  • t. Thus, total estimation

error can be written as

min lim

T→∞

1 T 𝔽 [

T−1

t=0

i∈N i≠St

di(Ei

t)

]

Defining the value of information

Value of Information (VOI)

The amount of money someone is willing to pay to access that information.

Defining the value of information

Value of Information (VOI)

The amount of money someone is willing to pay to access that information.

VOI for remote estimation

Suppose that there is a single sensor, say i, and a dedicated communication channel is available. The sensor has to pay an access fee λi each time it uses the channel.

Defining the value of information

Value of Information (VOI)

The amount of money someone is willing to pay to access that information.

VOI for remote estimation

Suppose that there is a single sensor, say i, and a dedicated communication channel is available. The sensor has to pay an access fee λi each time it uses the channel. Let Ui

t ∈ {0, 1} denote the sensor’s decision.

Then, the error process is Ei

t+1 =

{ Wi

t,

if Ui

t = 1

aiEi

t + Wi t

if Ui

t = 0

Defining the value of information

Value of Information (VOI)

The amount of money someone is willing to pay to access that information.

VOI for remote estimation

Suppose that there is a single sensor, say i, and a dedicated communication channel is available. The sensor has to pay an access fee λi each time it uses the channel. Let Ui

t ∈ {0, 1} denote the sensor’s decision.

Then, the error process is Ei

t+1 =

{ Wi

t,

if Ui

t = 1

aiEi

t + Wi t

if Ui

t = 0

Objective

min lim

T→∞

1 T 𝔽 [

T−1

t=0 [λiUi + (1 − Ui)di(Ei t)]]

Defining the value of information (cont.)

Optimal policy

The objective is a single agent multi-stage optimization problem. Optimal solution is given by dynamic programming.

Defining the value of information (cont.)

Optimal policy

The objective is a single agent multi-stage optimization problem. Optimal solution is given by dynamic programming. Let hi ∈ ℝ and vi∶ ℝ → ℝ satisfy the following dynamic program: for any e ∈ ℝ hi + vi(e) = min {λi + ∫

φi(w)vi(w)dw, di(e) + ∫

φi(w)vi(ae + w)dw}

slide-31
SLIDE 31

Remote estimation over CAN–(Mahajan)

9

What is Value of Information?

A change of variables

Error process

Defjne Ei

0 = Xi 0 and for t ≥ 0,

Ei

t+1 =

{ Wi

t,

if St = i aiEi

t + Wi t

if St ≠ i

A change of variables

Error process

Defjne Ei

0 = Xi 0 and for t ≥ 0,

Ei

t+1 =

{ Wi

t,

if St = i aiEi

t + Wi t

if St ≠ i Called the error process because when St ≠ i, Xt − ˆ Xi

t = Ei

  • t. Thus, total estimation

error can be written as

min lim

T→∞

1 T 𝔽 [

T−1

t=0

i∈N i≠St

di(Ei

t)

]

Defining the value of information

Value of Information (VOI)

The amount of money someone is willing to pay to access that information.

Defining the value of information

Value of Information (VOI)

The amount of money someone is willing to pay to access that information.

VOI for remote estimation

Suppose that there is a single sensor, say i, and a dedicated communication channel is available. The sensor has to pay an access fee λi each time it uses the channel.

Defining the value of information

Value of Information (VOI)

The amount of money someone is willing to pay to access that information.

VOI for remote estimation

Suppose that there is a single sensor, say i, and a dedicated communication channel is available. The sensor has to pay an access fee λi each time it uses the channel. Let Ui

t ∈ {0, 1} denote the sensor’s decision.

Then, the error process is Ei

t+1 =

{ Wi

t,

if Ui

t = 1

aiEi

t + Wi t

if Ui

t = 0

Defining the value of information

Value of Information (VOI)

The amount of money someone is willing to pay to access that information.

VOI for remote estimation

Suppose that there is a single sensor, say i, and a dedicated communication channel is available. The sensor has to pay an access fee λi each time it uses the channel. Let Ui

t ∈ {0, 1} denote the sensor’s decision.

Then, the error process is Ei

t+1 =

{ Wi

t,

if Ui

t = 1

aiEi

t + Wi t

if Ui

t = 0

Objective

min lim

T→∞

1 T 𝔽 [

T−1

t=0 [λiUi + (1 − Ui)di(Ei t)]]

Defining the value of information (cont.)

Optimal policy

The objective is a single agent multi-stage optimization problem. Optimal solution is given by dynamic programming.

Defining the value of information (cont.)

Optimal policy

The objective is a single agent multi-stage optimization problem. Optimal solution is given by dynamic programming. Let hi ∈ ℝ and vi∶ ℝ → ℝ satisfy the following dynamic program: for any e ∈ ℝ hi + vi(e) = min {λi + ∫

φi(w)vi(w)dw, di(e) + ∫

φi(w)vi(ae + w)dw}

Defining the value of information (cont.)

Optimal policy

The objective is a single agent multi-stage optimization problem. Optimal solution is given by dynamic programming. Let hi ∈ ℝ and vi∶ ℝ → ℝ satisfy the following dynamic program: for any e ∈ ℝ hi + vi(e) = min {λi + ∫

φi(w)vi(w)dw, di(e) + ∫

φi(w)vi(ae + w)dw} Let fi

∗(e) = 0 if the fjrst term is smaller and fi ∗(e) = 1 if the second term is smaller.

Then, fi

∗(e) is the optimal action at state e.

slide-32
SLIDE 32

Remote estimation over CAN–(Mahajan)

9

What is Value of Information?

A change of variables

Error process

Defjne Ei

0 = Xi 0 and for t ≥ 0,

Ei

t+1 =

{ Wi

t,

if St = i aiEi

t + Wi t

if St ≠ i

A change of variables

Error process

Defjne Ei

0 = Xi 0 and for t ≥ 0,

Ei

t+1 =

{ Wi

t,

if St = i aiEi

t + Wi t

if St ≠ i Called the error process because when St ≠ i, Xt − ˆ Xi

t = Ei

  • t. Thus, total estimation

error can be written as

min lim

T→∞

1 T 𝔽 [

T−1

t=0

i∈N i≠St

di(Ei

t)

]

Defining the value of information

Value of Information (VOI)

The amount of money someone is willing to pay to access that information.

Defining the value of information

Value of Information (VOI)

The amount of money someone is willing to pay to access that information.

VOI for remote estimation

Suppose that there is a single sensor, say i, and a dedicated communication channel is available. The sensor has to pay an access fee λi each time it uses the channel.

Defining the value of information

Value of Information (VOI)

The amount of money someone is willing to pay to access that information.

VOI for remote estimation

Suppose that there is a single sensor, say i, and a dedicated communication channel is available. The sensor has to pay an access fee λi each time it uses the channel. Let Ui

t ∈ {0, 1} denote the sensor’s decision.

Then, the error process is Ei

t+1 =

{ Wi

t,

if Ui

t = 1

aiEi

t + Wi t

if Ui

t = 0

Defining the value of information

Value of Information (VOI)

The amount of money someone is willing to pay to access that information.

VOI for remote estimation

Suppose that there is a single sensor, say i, and a dedicated communication channel is available. The sensor has to pay an access fee λi each time it uses the channel. Let Ui

t ∈ {0, 1} denote the sensor’s decision.

Then, the error process is Ei

t+1 =

{ Wi

t,

if Ui

t = 1

aiEi

t + Wi t

if Ui

t = 0

Objective

min lim

T→∞

1 T 𝔽 [

T−1

t=0 [λiUi + (1 − Ui)di(Ei t)]]

Defining the value of information (cont.)

Optimal policy

The objective is a single agent multi-stage optimization problem. Optimal solution is given by dynamic programming.

Defining the value of information (cont.)

Optimal policy

The objective is a single agent multi-stage optimization problem. Optimal solution is given by dynamic programming. Let hi ∈ ℝ and vi∶ ℝ → ℝ satisfy the following dynamic program: for any e ∈ ℝ hi + vi(e) = min {λi + ∫

φi(w)vi(w)dw, di(e) + ∫

φi(w)vi(ae + w)dw}

Defining the value of information (cont.)

Optimal policy

The objective is a single agent multi-stage optimization problem. Optimal solution is given by dynamic programming. Let hi ∈ ℝ and vi∶ ℝ → ℝ satisfy the following dynamic program: for any e ∈ ℝ hi + vi(e) = min {λi + ∫

φi(w)vi(w)dw, di(e) + ∫

φi(w)vi(ae + w)dw} Let fi

∗(e) = 0 if the fjrst term is smaller and fi ∗(e) = 1 if the second term is smaller.

Then, fi

∗(e) is the optimal action at state e.

Defining the value of information (cont.)

Optimal policy

The objective is a single agent multi-stage optimization problem. Optimal solution is given by dynamic programming. Let hi ∈ ℝ and vi∶ ℝ → ℝ satisfy the following dynamic program: for any e ∈ ℝ hi + vi(e) = min {λi + ∫

φi(w)vi(w)dw, di(e) + ∫

φi(w)vi(ae + w)dw} Let fi

∗(e) = 0 if the fjrst term is smaller and fi ∗(e) = 1 if the second term is smaller.

Then, fi

∗(e) is the optimal action at state e.

Theorem (Structure

  • f optimal policy)

There exists a threshold ki(λi) such that the optimal policy is of the form fi

∗(e) =

{ 1, if |e| < ki(λi) 0,

  • therwise.

Moreover, at k∗(λ∗), λi + ∫

φi(w)vi(w)dw = di(e) + ∫

φi(w)vi(ae + w)dw

Proof relies on stochastic monot-

  • nicity, stochastic dominance, and

submodularity.

slide-33
SLIDE 33

Remote estimation over CAN–(Mahajan)

9

What is Value of Information?

A change of variables

Error process

Defjne Ei

0 = Xi 0 and for t ≥ 0,

Ei

t+1 =

{ Wi

t,

if St = i aiEi

t + Wi t

if St ≠ i

A change of variables

Error process

Defjne Ei

0 = Xi 0 and for t ≥ 0,

Ei

t+1 =

{ Wi

t,

if St = i aiEi

t + Wi t

if St ≠ i Called the error process because when St ≠ i, Xt − ˆ Xi

t = Ei

  • t. Thus, total estimation

error can be written as

min lim

T→∞

1 T 𝔽 [

T−1

t=0

i∈N i≠St

di(Ei

t)

]

Defining the value of information

Value of Information (VOI)

The amount of money someone is willing to pay to access that information.

Defining the value of information

Value of Information (VOI)

The amount of money someone is willing to pay to access that information.

VOI for remote estimation

Suppose that there is a single sensor, say i, and a dedicated communication channel is available. The sensor has to pay an access fee λi each time it uses the channel.

Defining the value of information

Value of Information (VOI)

The amount of money someone is willing to pay to access that information.

VOI for remote estimation

Suppose that there is a single sensor, say i, and a dedicated communication channel is available. The sensor has to pay an access fee λi each time it uses the channel. Let Ui

t ∈ {0, 1} denote the sensor’s decision.

Then, the error process is Ei

t+1 =

{ Wi

t,

if Ui

t = 1

aiEi

t + Wi t

if Ui

t = 0

Defining the value of information

Value of Information (VOI)

The amount of money someone is willing to pay to access that information.

VOI for remote estimation

Suppose that there is a single sensor, say i, and a dedicated communication channel is available. The sensor has to pay an access fee λi each time it uses the channel. Let Ui

t ∈ {0, 1} denote the sensor’s decision.

Then, the error process is Ei

t+1 =

{ Wi

t,

if Ui

t = 1

aiEi

t + Wi t

if Ui

t = 0

Objective

min lim

T→∞

1 T 𝔽 [

T−1

t=0 [λiUi + (1 − Ui)di(Ei t)]]

Defining the value of information (cont.)

Optimal policy

The objective is a single agent multi-stage optimization problem. Optimal solution is given by dynamic programming.

Defining the value of information (cont.)

Optimal policy

The objective is a single agent multi-stage optimization problem. Optimal solution is given by dynamic programming. Let hi ∈ ℝ and vi∶ ℝ → ℝ satisfy the following dynamic program: for any e ∈ ℝ hi + vi(e) = min {λi + ∫

φi(w)vi(w)dw, di(e) + ∫

φi(w)vi(ae + w)dw}

Defining the value of information (cont.)

Optimal policy

The objective is a single agent multi-stage optimization problem. Optimal solution is given by dynamic programming. Let hi ∈ ℝ and vi∶ ℝ → ℝ satisfy the following dynamic program: for any e ∈ ℝ hi + vi(e) = min {λi + ∫

φi(w)vi(w)dw, di(e) + ∫

φi(w)vi(ae + w)dw} Let fi

∗(e) = 0 if the fjrst term is smaller and fi ∗(e) = 1 if the second term is smaller.

Then, fi

∗(e) is the optimal action at state e.

Defining the value of information (cont.)

Optimal policy

The objective is a single agent multi-stage optimization problem. Optimal solution is given by dynamic programming. Let hi ∈ ℝ and vi∶ ℝ → ℝ satisfy the following dynamic program: for any e ∈ ℝ hi + vi(e) = min {λi + ∫

φi(w)vi(w)dw, di(e) + ∫

φi(w)vi(ae + w)dw} Let fi

∗(e) = 0 if the fjrst term is smaller and fi ∗(e) = 1 if the second term is smaller.

Then, fi

∗(e) is the optimal action at state e.

Theorem (Structure

  • f optimal policy)

There exists a threshold ki(λi) such that the optimal policy is of the form fi

∗(e) =

{ 1, if |e| < ki(λi) 0,

  • therwise.

Moreover, at k∗(λ∗), λi + ∫

φi(w)vi(w)dw = di(e) + ∫

φi(w)vi(ae + w)dw

Proof relies on stochastic monot-

  • nicity, stochastic dominance, and

submodularity.

Defining the value of information (cont.)

Optimal policy

The objective is a single agent multi-stage optimization problem. Optimal solution is given by dynamic programming. Let hi ∈ ℝ and vi∶ ℝ → ℝ satisfy the following dynamic program: for any e ∈ ℝ hi + vi(e) = min {λi + ∫

φi(w)vi(w)dw, di(e) + ∫

φi(w)vi(ae + w)dw} Let fi

∗(e) = 0 if the fjrst term is smaller and fi ∗(e) = 1 if the second term is smaller.

Then, fi

∗(e) is the optimal action at state e.

Theorem (Structure

  • f optimal policy)

There exists a threshold ki(λi) such that the optimal policy is of the form fi

∗(e) =

{ 1, if |e| < ki(λi) 0,

  • therwise.

Moreover, at k∗(λ∗), λi + ∫

φi(w)vi(w)dw = di(e) + ∫

φi(w)vi(ae + w)dw

Proof relies on stochastic monot-

  • nicity, stochastic dominance, and

submodularity.

VOI at e is the smallest value of access fee for which the sensor is indifgerent between transmitting and not transmitting when the state is |e|, i.e., VOIi(e) = inf {λi ∈ ℝ≥0 : ki(λi) = |e|}

slide-34
SLIDE 34

Remote estimation over CAN–(Mahajan)

9

What is Value of Information?

A change of variables

Error process

Defjne Ei

0 = Xi 0 and for t ≥ 0,

Ei

t+1 =

{ Wi

t,

if St = i aiEi

t + Wi t

if St ≠ i

A change of variables

Error process

Defjne Ei

0 = Xi 0 and for t ≥ 0,

Ei

t+1 =

{ Wi

t,

if St = i aiEi

t + Wi t

if St ≠ i Called the error process because when St ≠ i, Xt − ˆ Xi

t = Ei

  • t. Thus, total estimation

error can be written as

min lim

T→∞

1 T 𝔽 [

T−1

t=0

i∈N i≠St

di(Ei

t)

]

Defining the value of information

Value of Information (VOI)

The amount of money someone is willing to pay to access that information.

Defining the value of information

Value of Information (VOI)

The amount of money someone is willing to pay to access that information.

VOI for remote estimation

Suppose that there is a single sensor, say i, and a dedicated communication channel is available. The sensor has to pay an access fee λi each time it uses the channel.

Defining the value of information

Value of Information (VOI)

The amount of money someone is willing to pay to access that information.

VOI for remote estimation

Suppose that there is a single sensor, say i, and a dedicated communication channel is available. The sensor has to pay an access fee λi each time it uses the channel. Let Ui

t ∈ {0, 1} denote the sensor’s decision.

Then, the error process is Ei

t+1 =

{ Wi

t,

if Ui

t = 1

aiEi

t + Wi t

if Ui

t = 0

Defining the value of information

Value of Information (VOI)

The amount of money someone is willing to pay to access that information.

VOI for remote estimation

Suppose that there is a single sensor, say i, and a dedicated communication channel is available. The sensor has to pay an access fee λi each time it uses the channel. Let Ui

t ∈ {0, 1} denote the sensor’s decision.

Then, the error process is Ei

t+1 =

{ Wi

t,

if Ui

t = 1

aiEi

t + Wi t

if Ui

t = 0

Objective

min lim

T→∞

1 T 𝔽 [

T−1

t=0 [λiUi + (1 − Ui)di(Ei t)]]

Defining the value of information (cont.)

Optimal policy

The objective is a single agent multi-stage optimization problem. Optimal solution is given by dynamic programming.

Defining the value of information (cont.)

Optimal policy

The objective is a single agent multi-stage optimization problem. Optimal solution is given by dynamic programming. Let hi ∈ ℝ and vi∶ ℝ → ℝ satisfy the following dynamic program: for any e ∈ ℝ hi + vi(e) = min {λi + ∫

φi(w)vi(w)dw, di(e) + ∫

φi(w)vi(ae + w)dw}

Defining the value of information (cont.)

Optimal policy

The objective is a single agent multi-stage optimization problem. Optimal solution is given by dynamic programming. Let hi ∈ ℝ and vi∶ ℝ → ℝ satisfy the following dynamic program: for any e ∈ ℝ hi + vi(e) = min {λi + ∫

φi(w)vi(w)dw, di(e) + ∫

φi(w)vi(ae + w)dw} Let fi

∗(e) = 0 if the fjrst term is smaller and fi ∗(e) = 1 if the second term is smaller.

Then, fi

∗(e) is the optimal action at state e.

Defining the value of information (cont.)

Optimal policy

The objective is a single agent multi-stage optimization problem. Optimal solution is given by dynamic programming. Let hi ∈ ℝ and vi∶ ℝ → ℝ satisfy the following dynamic program: for any e ∈ ℝ hi + vi(e) = min {λi + ∫

φi(w)vi(w)dw, di(e) + ∫

φi(w)vi(ae + w)dw} Let fi

∗(e) = 0 if the fjrst term is smaller and fi ∗(e) = 1 if the second term is smaller.

Then, fi

∗(e) is the optimal action at state e.

Theorem (Structure

  • f optimal policy)

There exists a threshold ki(λi) such that the optimal policy is of the form fi

∗(e) =

{ 1, if |e| < ki(λi) 0,

  • therwise.

Moreover, at k∗(λ∗), λi + ∫

φi(w)vi(w)dw = di(e) + ∫

φi(w)vi(ae + w)dw

Proof relies on stochastic monot-

  • nicity, stochastic dominance, and

submodularity.

Defining the value of information (cont.)

Optimal policy

The objective is a single agent multi-stage optimization problem. Optimal solution is given by dynamic programming. Let hi ∈ ℝ and vi∶ ℝ → ℝ satisfy the following dynamic program: for any e ∈ ℝ hi + vi(e) = min {λi + ∫

φi(w)vi(w)dw, di(e) + ∫

φi(w)vi(ae + w)dw} Let fi

∗(e) = 0 if the fjrst term is smaller and fi ∗(e) = 1 if the second term is smaller.

Then, fi

∗(e) is the optimal action at state e.

Theorem (Structure

  • f optimal policy)

There exists a threshold ki(λi) such that the optimal policy is of the form fi

∗(e) =

{ 1, if |e| < ki(λi) 0,

  • therwise.

Moreover, at k∗(λ∗), λi + ∫

φi(w)vi(w)dw = di(e) + ∫

φi(w)vi(ae + w)dw

Proof relies on stochastic monot-

  • nicity, stochastic dominance, and

submodularity.

VOI at e is the smallest value of access fee for which the sensor is indifgerent between transmitting and not transmitting when the state is |e|, i.e., VOIi(e) = inf {λi ∈ ℝ≥0 : ki(λi) = |e|}

slide-35
SLIDE 35

Remote estimation over CAN–(Mahajan)

13

How to compute value of information?

slide-36
SLIDE 36

Remote estimation over CAN–(Mahajan)

13

How to compute value of information?

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

slide-37
SLIDE 37

Remote estimation over CAN–(Mahajan)

13

How to compute value of information?

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

First simplification

Let fi

k denote the threshold policy with threshold k.

Defjne Di

k = lim T→∞

1 T 𝔽 [

T−1

t=0

(1 − Ui

t)di(Ei t)

] and Ni

k = lim T→∞

1 T 𝔽 [

T−1

t=0

Ui

t]

slide-38
SLIDE 38

Remote estimation over CAN–(Mahajan)

13

How to compute value of information?

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

First simplification

Let fi

k denote the threshold policy with threshold k.

Defjne Di

k = lim T→∞

1 T 𝔽 [

T−1

t=0

(1 − Ui

t)di(Ei t)

] and Ni

k = lim T→∞

1 T 𝔽 [

T−1

t=0

Ui

t]

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

First simplification

Let fi

k denote the threshold policy with threshold k.

Defjne Di

k = lim T→∞

1 T 𝔽 [

T−1

t=0

(1 − Ui

t)di(Ei t)

] and Ni

k = lim T→∞

1 T 𝔽 [

T−1

t=0

Ui

t]

Then, Ji(fi

k) = Di k + λiNi

  • k. The policy is optimal if ∂kDi

k + λi∂kNi k = 0.

Therefore, VOIi(k) = −∂kDi

k

∂kNi

k

slide-39
SLIDE 39

Remote estimation over CAN–(Mahajan)

13

How to compute value of information?

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

First simplification

Let fi

k denote the threshold policy with threshold k.

Defjne Di

k = lim T→∞

1 T 𝔽 [

T−1

t=0

(1 − Ui

t)di(Ei t)

] and Ni

k = lim T→∞

1 T 𝔽 [

T−1

t=0

Ui

t]

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

First simplification

Let fi

k denote the threshold policy with threshold k.

Defjne Di

k = lim T→∞

1 T 𝔽 [

T−1

t=0

(1 − Ui

t)di(Ei t)

] and Ni

k = lim T→∞

1 T 𝔽 [

T−1

t=0

Ui

t]

Then, Ji(fi

k) = Di k + λiNi

  • k. The policy is optimal if ∂kDi

k + λi∂kNi k = 0.

Therefore, VOIi(k) = −∂kDi

k

∂kNi

k

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

slide-40
SLIDE 40

Remote estimation over CAN–(Mahajan)

13

How to compute value of information?

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

First simplification

Let fi

k denote the threshold policy with threshold k.

Defjne Di

k = lim T→∞

1 T 𝔽 [

T−1

t=0

(1 − Ui

t)di(Ei t)

] and Ni

k = lim T→∞

1 T 𝔽 [

T−1

t=0

Ui

t]

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

First simplification

Let fi

k denote the threshold policy with threshold k.

Defjne Di

k = lim T→∞

1 T 𝔽 [

T−1

t=0

(1 − Ui

t)di(Ei t)

] and Ni

k = lim T→∞

1 T 𝔽 [

T−1

t=0

Ui

t]

Then, Ji(fi

k) = Di k + λiNi

  • k. The policy is optimal if ∂kDi

k + λi∂kNi k = 0.

Therefore, VOIi(k) = −∂kDi

k

∂kNi

k

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Then, from renewal theory: Di

k = Li k(0)

Mi

k(0) and Ni k =

1 Mi

k(0) .

slide-41
SLIDE 41

Remote estimation over CAN–(Mahajan)

13

How to compute value of information?

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

First simplification

Let fi

k denote the threshold policy with threshold k.

Defjne Di

k = lim T→∞

1 T 𝔽 [

T−1

t=0

(1 − Ui

t)di(Ei t)

] and Ni

k = lim T→∞

1 T 𝔽 [

T−1

t=0

Ui

t]

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

First simplification

Let fi

k denote the threshold policy with threshold k.

Defjne Di

k = lim T→∞

1 T 𝔽 [

T−1

t=0

(1 − Ui

t)di(Ei t)

] and Ni

k = lim T→∞

1 T 𝔽 [

T−1

t=0

Ui

t]

Then, Ji(fi

k) = Di k + λiNi

  • k. The policy is optimal if ∂kDi

k + λi∂kNi k = 0.

Therefore, VOIi(k) = −∂kDi

k

∂kNi

k

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Then, from renewal theory: Di

k = Li k(0)

Mi

k(0) and Ni k =

1 Mi

k(0) .

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Then, from renewal theory: Di

k = Li k(0)

Mi

k(0) and Ni k =

1 Mi

k(0) .

Therefore, VOIi(k) = Mi

k(0) ∂kLi k(0)

∂kMi

k(0) − Li k(0)

slide-42
SLIDE 42

Remote estimation over CAN–(Mahajan)

13

How to compute value of information?

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

First simplification

Let fi

k denote the threshold policy with threshold k.

Defjne Di

k = lim T→∞

1 T 𝔽 [

T−1

t=0

(1 − Ui

t)di(Ei t)

] and Ni

k = lim T→∞

1 T 𝔽 [

T−1

t=0

Ui

t]

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

First simplification

Let fi

k denote the threshold policy with threshold k.

Defjne Di

k = lim T→∞

1 T 𝔽 [

T−1

t=0

(1 − Ui

t)di(Ei t)

] and Ni

k = lim T→∞

1 T 𝔽 [

T−1

t=0

Ui

t]

Then, Ji(fi

k) = Di k + λiNi

  • k. The policy is optimal if ∂kDi

k + λi∂kNi k = 0.

Therefore, VOIi(k) = −∂kDi

k

∂kNi

k

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Then, from renewal theory: Di

k = Li k(0)

Mi

k(0) and Ni k =

1 Mi

k(0) .

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Then, from renewal theory: Di

k = Li k(0)

Mi

k(0) and Ni k =

1 Mi

k(0) .

Therefore, VOIi(k) = Mi

k(0) ∂kLi k(0)

∂kMi

k(0) − Li k(0)

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Then, from renewal theory: Di

k = Li k(0)

Mi

k(0) and Ni k =

1 Mi

k(0) .

Therefore, VOIi(k) = Mi

k(0) ∂kLi k(0)

∂kMi

k(0) − Li k(0)

Need to compute Mi

k(0), Li k(0), ∂kMi k(0), ∂kLi k(0) to compute VOI.

slide-43
SLIDE 43

Remote estimation over CAN–(Mahajan)

13

How to compute value of information?

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

First simplification

Let fi

k denote the threshold policy with threshold k.

Defjne Di

k = lim T→∞

1 T 𝔽 [

T−1

t=0

(1 − Ui

t)di(Ei t)

] and Ni

k = lim T→∞

1 T 𝔽 [

T−1

t=0

Ui

t]

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

First simplification

Let fi

k denote the threshold policy with threshold k.

Defjne Di

k = lim T→∞

1 T 𝔽 [

T−1

t=0

(1 − Ui

t)di(Ei t)

] and Ni

k = lim T→∞

1 T 𝔽 [

T−1

t=0

Ui

t]

Then, Ji(fi

k) = Di k + λiNi

  • k. The policy is optimal if ∂kDi

k + λi∂kNi k = 0.

Therefore, VOIi(k) = −∂kDi

k

∂kNi

k

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Then, from renewal theory: Di

k = Li k(0)

Mi

k(0) and Ni k =

1 Mi

k(0) .

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Then, from renewal theory: Di

k = Li k(0)

Mi

k(0) and Ni k =

1 Mi

k(0) .

Therefore, VOIi(k) = Mi

k(0) ∂kLi k(0)

∂kMi

k(0) − Li k(0)

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Then, from renewal theory: Di

k = Li k(0)

Mi

k(0) and Ni k =

1 Mi

k(0) .

Therefore, VOIi(k) = Mi

k(0) ∂kLi k(0)

∂kMi

k(0) − Li k(0)

Need to compute Mi

k(0), Li k(0), ∂kMi k(0), ∂kLi k(0) to compute VOI.

Computing 𝐌𝐣

𝐥(𝟏) and 𝐍𝐣 𝐥(𝟏) Balance equation

Li

k(x) = di k(x) + ∫ k −k

φi(y − ax)Li

k(y)dy

(Fredholm integral eqn of the 2nd kind)

slide-44
SLIDE 44

Remote estimation over CAN–(Mahajan)

13

How to compute value of information?

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

First simplification

Let fi

k denote the threshold policy with threshold k.

Defjne Di

k = lim T→∞

1 T 𝔽 [

T−1

t=0

(1 − Ui

t)di(Ei t)

] and Ni

k = lim T→∞

1 T 𝔽 [

T−1

t=0

Ui

t]

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

First simplification

Let fi

k denote the threshold policy with threshold k.

Defjne Di

k = lim T→∞

1 T 𝔽 [

T−1

t=0

(1 − Ui

t)di(Ei t)

] and Ni

k = lim T→∞

1 T 𝔽 [

T−1

t=0

Ui

t]

Then, Ji(fi

k) = Di k + λiNi

  • k. The policy is optimal if ∂kDi

k + λi∂kNi k = 0.

Therefore, VOIi(k) = −∂kDi

k

∂kNi

k

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Then, from renewal theory: Di

k = Li k(0)

Mi

k(0) and Ni k =

1 Mi

k(0) .

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Then, from renewal theory: Di

k = Li k(0)

Mi

k(0) and Ni k =

1 Mi

k(0) .

Therefore, VOIi(k) = Mi

k(0) ∂kLi k(0)

∂kMi

k(0) − Li k(0)

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Then, from renewal theory: Di

k = Li k(0)

Mi

k(0) and Ni k =

1 Mi

k(0) .

Therefore, VOIi(k) = Mi

k(0) ∂kLi k(0)

∂kMi

k(0) − Li k(0)

Need to compute Mi

k(0), Li k(0), ∂kMi k(0), ∂kLi k(0) to compute VOI.

Computing 𝐌𝐣

𝐥(𝟏) and 𝐍𝐣 𝐥(𝟏) Balance equation

Li

k(x) = di k(x) + ∫ k −k

φi(y − ax)Li

k(y)dy

(Fredholm integral eqn of the 2nd kind)

Computing 𝐌𝐣

𝐥(𝟏) and 𝐍𝐣 𝐥(𝟏) Balance equation

Li

k(x) = di k(x) + ∫ k −k

φi(y − ax)Li

k(y)dy

(Fredholm integral eqn of the 2nd kind)

Solution using quadrature method

Let {w−m, . . . , wm} and {x−m, . . . , xm} be the weights and abscissas for any quadrature rule of 2m + 1 points over [−k, k]. Then the above integral equation can be approximated as Li

k(xp) ≈ di(xp) + m

q=−m

wqφi(xp − axq)Li

k(xq)

slide-45
SLIDE 45

Remote estimation over CAN–(Mahajan)

13

How to compute value of information?

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

First simplification

Let fi

k denote the threshold policy with threshold k.

Defjne Di

k = lim T→∞

1 T 𝔽 [

T−1

t=0

(1 − Ui

t)di(Ei t)

] and Ni

k = lim T→∞

1 T 𝔽 [

T−1

t=0

Ui

t]

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

First simplification

Let fi

k denote the threshold policy with threshold k.

Defjne Di

k = lim T→∞

1 T 𝔽 [

T−1

t=0

(1 − Ui

t)di(Ei t)

] and Ni

k = lim T→∞

1 T 𝔽 [

T−1

t=0

Ui

t]

Then, Ji(fi

k) = Di k + λiNi

  • k. The policy is optimal if ∂kDi

k + λi∂kNi k = 0.

Therefore, VOIi(k) = −∂kDi

k

∂kNi

k

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Then, from renewal theory: Di

k = Li k(0)

Mi

k(0) and Ni k =

1 Mi

k(0) .

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Then, from renewal theory: Di

k = Li k(0)

Mi

k(0) and Ni k =

1 Mi

k(0) .

Therefore, VOIi(k) = Mi

k(0) ∂kLi k(0)

∂kMi

k(0) − Li k(0)

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Then, from renewal theory: Di

k = Li k(0)

Mi

k(0) and Ni k =

1 Mi

k(0) .

Therefore, VOIi(k) = Mi

k(0) ∂kLi k(0)

∂kMi

k(0) − Li k(0)

Need to compute Mi

k(0), Li k(0), ∂kMi k(0), ∂kLi k(0) to compute VOI.

Computing 𝐌𝐣

𝐥(𝟏) and 𝐍𝐣 𝐥(𝟏) Balance equation

Li

k(x) = di k(x) + ∫ k −k

φi(y − ax)Li

k(y)dy

(Fredholm integral eqn of the 2nd kind)

Computing 𝐌𝐣

𝐥(𝟏) and 𝐍𝐣 𝐥(𝟏) Balance equation

Li

k(x) = di k(x) + ∫ k −k

φi(y − ax)Li

k(y)dy

(Fredholm integral eqn of the 2nd kind)

Solution using quadrature method

Let {w−m, . . . , wm} and {x−m, . . . , xm} be the weights and abscissas for any quadrature rule of 2m + 1 points over [−k, k]. Then the above integral equation can be approximated as Li

k(xp) ≈ di(xp) + m

q=−m

wqφi(xp − axq)Li

k(xq)

Computing 𝐌𝐣

𝐥(𝟏) and 𝐍𝐣 𝐥(𝟏) Balance equation

Li

k(x) = di k(x) + ∫ k −k

φi(y − ax)Li

k(y)dy

(Fredholm integral eqn of the 2nd kind)

Solution using quadrature method

Let {w−m, . . . , wm} and {x−m, . . . , xm} be the weights and abscissas for any quadrature rule of 2m + 1 points over [−k, k]. Then the above integral equation can be approximated as Li

k(xp) ≈ di(xp) + m

q=−m

wqφi(xp − axq)Li

k(xq)

Or, in matrix form, 𝐌i = (𝐉 − 𝚾i)−1𝐞i

slide-46
SLIDE 46

Remote estimation over CAN–(Mahajan)

13

How to compute value of information?

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

First simplification

Let fi

k denote the threshold policy with threshold k.

Defjne Di

k = lim T→∞

1 T 𝔽 [

T−1

t=0

(1 − Ui

t)di(Ei t)

] and Ni

k = lim T→∞

1 T 𝔽 [

T−1

t=0

Ui

t]

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

First simplification

Let fi

k denote the threshold policy with threshold k.

Defjne Di

k = lim T→∞

1 T 𝔽 [

T−1

t=0

(1 − Ui

t)di(Ei t)

] and Ni

k = lim T→∞

1 T 𝔽 [

T−1

t=0

Ui

t]

Then, Ji(fi

k) = Di k + λiNi

  • k. The policy is optimal if ∂kDi

k + λi∂kNi k = 0.

Therefore, VOIi(k) = −∂kDi

k

∂kNi

k

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Then, from renewal theory: Di

k = Li k(0)

Mi

k(0) and Ni k =

1 Mi

k(0) .

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Then, from renewal theory: Di

k = Li k(0)

Mi

k(0) and Ni k =

1 Mi

k(0) .

Therefore, VOIi(k) = Mi

k(0) ∂kLi k(0)

∂kMi

k(0) − Li k(0)

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Then, from renewal theory: Di

k = Li k(0)

Mi

k(0) and Ni k =

1 Mi

k(0) .

Therefore, VOIi(k) = Mi

k(0) ∂kLi k(0)

∂kMi

k(0) − Li k(0)

Need to compute Mi

k(0), Li k(0), ∂kMi k(0), ∂kLi k(0) to compute VOI.

Computing 𝐌𝐣

𝐥(𝟏) and 𝐍𝐣 𝐥(𝟏) Balance equation

Li

k(x) = di k(x) + ∫ k −k

φi(y − ax)Li

k(y)dy

(Fredholm integral eqn of the 2nd kind)

Computing 𝐌𝐣

𝐥(𝟏) and 𝐍𝐣 𝐥(𝟏) Balance equation

Li

k(x) = di k(x) + ∫ k −k

φi(y − ax)Li

k(y)dy

(Fredholm integral eqn of the 2nd kind)

Solution using quadrature method

Let {w−m, . . . , wm} and {x−m, . . . , xm} be the weights and abscissas for any quadrature rule of 2m + 1 points over [−k, k]. Then the above integral equation can be approximated as Li

k(xp) ≈ di(xp) + m

q=−m

wqφi(xp − axq)Li

k(xq)

Computing 𝐌𝐣

𝐥(𝟏) and 𝐍𝐣 𝐥(𝟏) Balance equation

Li

k(x) = di k(x) + ∫ k −k

φi(y − ax)Li

k(y)dy

(Fredholm integral eqn of the 2nd kind)

Solution using quadrature method

Let {w−m, . . . , wm} and {x−m, . . . , xm} be the weights and abscissas for any quadrature rule of 2m + 1 points over [−k, k]. Then the above integral equation can be approximated as Li

k(xp) ≈ di(xp) + m

q=−m

wqφi(xp − axq)Li

k(xq)

Or, in matrix form, 𝐌i = (𝐉 − 𝚾i)−1𝐞i

Computing 𝐌𝐣

𝐥(𝟏) and 𝐍𝐣 𝐥(𝟏) Balance equation

Li

k(x) = di k(x) + ∫ k −k

φi(y − ax)Li

k(y)dy

(Fredholm integral eqn of the 2nd kind)

Solution using quadrature method

Let {w−m, . . . , wm} and {x−m, . . . , xm} be the weights and abscissas for any quadrature rule of 2m + 1 points over [−k, k]. Then the above integral equation can be approximated as Li

k(xp) ≈ di(xp) + m

q=−m

wqφi(xp − axq)Li

k(xq)

Or, in matrix form, 𝐌i = (𝐉 − 𝚾i)−1𝐞i and 𝐍i = (𝐉 − 𝚾i)−1𝟐

slide-47
SLIDE 47

Remote estimation over CAN–(Mahajan)

13

How to compute value of information?

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

First simplification

Let fi

k denote the threshold policy with threshold k.

Defjne Di

k = lim T→∞

1 T 𝔽 [

T−1

t=0

(1 − Ui

t)di(Ei t)

] and Ni

k = lim T→∞

1 T 𝔽 [

T−1

t=0

Ui

t]

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

First simplification

Let fi

k denote the threshold policy with threshold k.

Defjne Di

k = lim T→∞

1 T 𝔽 [

T−1

t=0

(1 − Ui

t)di(Ei t)

] and Ni

k = lim T→∞

1 T 𝔽 [

T−1

t=0

Ui

t]

Then, Ji(fi

k) = Di k + λiNi

  • k. The policy is optimal if ∂kDi

k + λi∂kNi k = 0.

Therefore, VOIi(k) = −∂kDi

k

∂kNi

k

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Then, from renewal theory: Di

k = Li k(0)

Mi

k(0) and Ni k =

1 Mi

k(0) .

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Then, from renewal theory: Di

k = Li k(0)

Mi

k(0) and Ni k =

1 Mi

k(0) .

Therefore, VOIi(k) = Mi

k(0) ∂kLi k(0)

∂kMi

k(0) − Li k(0)

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Then, from renewal theory: Di

k = Li k(0)

Mi

k(0) and Ni k =

1 Mi

k(0) .

Therefore, VOIi(k) = Mi

k(0) ∂kLi k(0)

∂kMi

k(0) − Li k(0)

Need to compute Mi

k(0), Li k(0), ∂kMi k(0), ∂kLi k(0) to compute VOI.

Computing 𝐌𝐣

𝐥(𝟏) and 𝐍𝐣 𝐥(𝟏) Balance equation

Li

k(x) = di k(x) + ∫ k −k

φi(y − ax)Li

k(y)dy

(Fredholm integral eqn of the 2nd kind)

Computing 𝐌𝐣

𝐥(𝟏) and 𝐍𝐣 𝐥(𝟏) Balance equation

Li

k(x) = di k(x) + ∫ k −k

φi(y − ax)Li

k(y)dy

(Fredholm integral eqn of the 2nd kind)

Solution using quadrature method

Let {w−m, . . . , wm} and {x−m, . . . , xm} be the weights and abscissas for any quadrature rule of 2m + 1 points over [−k, k]. Then the above integral equation can be approximated as Li

k(xp) ≈ di(xp) + m

q=−m

wqφi(xp − axq)Li

k(xq)

Computing 𝐌𝐣

𝐥(𝟏) and 𝐍𝐣 𝐥(𝟏) Balance equation

Li

k(x) = di k(x) + ∫ k −k

φi(y − ax)Li

k(y)dy

(Fredholm integral eqn of the 2nd kind)

Solution using quadrature method

Let {w−m, . . . , wm} and {x−m, . . . , xm} be the weights and abscissas for any quadrature rule of 2m + 1 points over [−k, k]. Then the above integral equation can be approximated as Li

k(xp) ≈ di(xp) + m

q=−m

wqφi(xp − axq)Li

k(xq)

Or, in matrix form, 𝐌i = (𝐉 − 𝚾i)−1𝐞i

Computing 𝐌𝐣

𝐥(𝟏) and 𝐍𝐣 𝐥(𝟏) Balance equation

Li

k(x) = di k(x) + ∫ k −k

φi(y − ax)Li

k(y)dy

(Fredholm integral eqn of the 2nd kind)

Solution using quadrature method

Let {w−m, . . . , wm} and {x−m, . . . , xm} be the weights and abscissas for any quadrature rule of 2m + 1 points over [−k, k]. Then the above integral equation can be approximated as Li

k(xp) ≈ di(xp) + m

q=−m

wqφi(xp − axq)Li

k(xq)

Or, in matrix form, 𝐌i = (𝐉 − 𝚾i)−1𝐞i and 𝐍i = (𝐉 − 𝚾i)−1𝟐

Computing ∂𝐥𝐌𝐣

𝐥(𝟏) and ∂𝐥𝐍𝐣 𝐥(𝟏) Balance equation

Li

k(x) = di k(x) + ∫ k −k

φi(y − ax)Li

k(y)dy

slide-48
SLIDE 48

Remote estimation over CAN–(Mahajan)

13

How to compute value of information?

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

First simplification

Let fi

k denote the threshold policy with threshold k.

Defjne Di

k = lim T→∞

1 T 𝔽 [

T−1

t=0

(1 − Ui

t)di(Ei t)

] and Ni

k = lim T→∞

1 T 𝔽 [

T−1

t=0

Ui

t]

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

First simplification

Let fi

k denote the threshold policy with threshold k.

Defjne Di

k = lim T→∞

1 T 𝔽 [

T−1

t=0

(1 − Ui

t)di(Ei t)

] and Ni

k = lim T→∞

1 T 𝔽 [

T−1

t=0

Ui

t]

Then, Ji(fi

k) = Di k + λiNi

  • k. The policy is optimal if ∂kDi

k + λi∂kNi k = 0.

Therefore, VOIi(k) = −∂kDi

k

∂kNi

k

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Then, from renewal theory: Di

k = Li k(0)

Mi

k(0) and Ni k =

1 Mi

k(0) .

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Then, from renewal theory: Di

k = Li k(0)

Mi

k(0) and Ni k =

1 Mi

k(0) .

Therefore, VOIi(k) = Mi

k(0) ∂kLi k(0)

∂kMi

k(0) − Li k(0)

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Then, from renewal theory: Di

k = Li k(0)

Mi

k(0) and Ni k =

1 Mi

k(0) .

Therefore, VOIi(k) = Mi

k(0) ∂kLi k(0)

∂kMi

k(0) − Li k(0)

Need to compute Mi

k(0), Li k(0), ∂kMi k(0), ∂kLi k(0) to compute VOI.

Computing 𝐌𝐣

𝐥(𝟏) and 𝐍𝐣 𝐥(𝟏) Balance equation

Li

k(x) = di k(x) + ∫ k −k

φi(y − ax)Li

k(y)dy

(Fredholm integral eqn of the 2nd kind)

Computing 𝐌𝐣

𝐥(𝟏) and 𝐍𝐣 𝐥(𝟏) Balance equation

Li

k(x) = di k(x) + ∫ k −k

φi(y − ax)Li

k(y)dy

(Fredholm integral eqn of the 2nd kind)

Solution using quadrature method

Let {w−m, . . . , wm} and {x−m, . . . , xm} be the weights and abscissas for any quadrature rule of 2m + 1 points over [−k, k]. Then the above integral equation can be approximated as Li

k(xp) ≈ di(xp) + m

q=−m

wqφi(xp − axq)Li

k(xq)

Computing 𝐌𝐣

𝐥(𝟏) and 𝐍𝐣 𝐥(𝟏) Balance equation

Li

k(x) = di k(x) + ∫ k −k

φi(y − ax)Li

k(y)dy

(Fredholm integral eqn of the 2nd kind)

Solution using quadrature method

Let {w−m, . . . , wm} and {x−m, . . . , xm} be the weights and abscissas for any quadrature rule of 2m + 1 points over [−k, k]. Then the above integral equation can be approximated as Li

k(xp) ≈ di(xp) + m

q=−m

wqφi(xp − axq)Li

k(xq)

Or, in matrix form, 𝐌i = (𝐉 − 𝚾i)−1𝐞i

Computing 𝐌𝐣

𝐥(𝟏) and 𝐍𝐣 𝐥(𝟏) Balance equation

Li

k(x) = di k(x) + ∫ k −k

φi(y − ax)Li

k(y)dy

(Fredholm integral eqn of the 2nd kind)

Solution using quadrature method

Let {w−m, . . . , wm} and {x−m, . . . , xm} be the weights and abscissas for any quadrature rule of 2m + 1 points over [−k, k]. Then the above integral equation can be approximated as Li

k(xp) ≈ di(xp) + m

q=−m

wqφi(xp − axq)Li

k(xq)

Or, in matrix form, 𝐌i = (𝐉 − 𝚾i)−1𝐞i and 𝐍i = (𝐉 − 𝚾i)−1𝟐

Computing ∂𝐥𝐌𝐣

𝐥(𝟏) and ∂𝐥𝐍𝐣 𝐥(𝟏) Balance equation

Li

k(x) = di k(x) + ∫ k −k

φi(y − ax)Li

k(y)dy

Computing ∂𝐥𝐌𝐣

𝐥(𝟏) and ∂𝐥𝐍𝐣 𝐥(𝟏) Balance equation

Li

k(x) = di k(x) + ∫ k −k

φi(y − ax)Li

k(y)dy

Take derivative

Using Leibniz rule ∂kLi

k(x) = φi(x − ak)Li k(x) + φi(x + ak)Li k(−k) + ∫ k −k

φi(x − ay)Li

k(y)dy

∂kMi

k(x) = φi(x − ak)Mi k(x) + φi(x + ak)Mi k(−k) + ∫ k −k

φi(x − ay)Mi

k(y)dy

slide-49
SLIDE 49

Remote estimation over CAN–(Mahajan)

13

How to compute value of information?

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

First simplification

Let fi

k denote the threshold policy with threshold k.

Defjne Di

k = lim T→∞

1 T 𝔽 [

T−1

t=0

(1 − Ui

t)di(Ei t)

] and Ni

k = lim T→∞

1 T 𝔽 [

T−1

t=0

Ui

t]

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

First simplification

Let fi

k denote the threshold policy with threshold k.

Defjne Di

k = lim T→∞

1 T 𝔽 [

T−1

t=0

(1 − Ui

t)di(Ei t)

] and Ni

k = lim T→∞

1 T 𝔽 [

T−1

t=0

Ui

t]

Then, Ji(fi

k) = Di k + λiNi

  • k. The policy is optimal if ∂kDi

k + λi∂kNi k = 0.

Therefore, VOIi(k) = −∂kDi

k

∂kNi

k

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Then, from renewal theory: Di

k = Li k(0)

Mi

k(0) and Ni k =

1 Mi

k(0) .

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Then, from renewal theory: Di

k = Li k(0)

Mi

k(0) and Ni k =

1 Mi

k(0) .

Therefore, VOIi(k) = Mi

k(0) ∂kLi k(0)

∂kMi

k(0) − Li k(0)

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Then, from renewal theory: Di

k = Li k(0)

Mi

k(0) and Ni k =

1 Mi

k(0) .

Therefore, VOIi(k) = Mi

k(0) ∂kLi k(0)

∂kMi

k(0) − Li k(0)

Need to compute Mi

k(0), Li k(0), ∂kMi k(0), ∂kLi k(0) to compute VOI.

Computing 𝐌𝐣

𝐥(𝟏) and 𝐍𝐣 𝐥(𝟏) Balance equation

Li

k(x) = di k(x) + ∫ k −k

φi(y − ax)Li

k(y)dy

(Fredholm integral eqn of the 2nd kind)

Computing 𝐌𝐣

𝐥(𝟏) and 𝐍𝐣 𝐥(𝟏) Balance equation

Li

k(x) = di k(x) + ∫ k −k

φi(y − ax)Li

k(y)dy

(Fredholm integral eqn of the 2nd kind)

Solution using quadrature method

Let {w−m, . . . , wm} and {x−m, . . . , xm} be the weights and abscissas for any quadrature rule of 2m + 1 points over [−k, k]. Then the above integral equation can be approximated as Li

k(xp) ≈ di(xp) + m

q=−m

wqφi(xp − axq)Li

k(xq)

Computing 𝐌𝐣

𝐥(𝟏) and 𝐍𝐣 𝐥(𝟏) Balance equation

Li

k(x) = di k(x) + ∫ k −k

φi(y − ax)Li

k(y)dy

(Fredholm integral eqn of the 2nd kind)

Solution using quadrature method

Let {w−m, . . . , wm} and {x−m, . . . , xm} be the weights and abscissas for any quadrature rule of 2m + 1 points over [−k, k]. Then the above integral equation can be approximated as Li

k(xp) ≈ di(xp) + m

q=−m

wqφi(xp − axq)Li

k(xq)

Or, in matrix form, 𝐌i = (𝐉 − 𝚾i)−1𝐞i

Computing 𝐌𝐣

𝐥(𝟏) and 𝐍𝐣 𝐥(𝟏) Balance equation

Li

k(x) = di k(x) + ∫ k −k

φi(y − ax)Li

k(y)dy

(Fredholm integral eqn of the 2nd kind)

Solution using quadrature method

Let {w−m, . . . , wm} and {x−m, . . . , xm} be the weights and abscissas for any quadrature rule of 2m + 1 points over [−k, k]. Then the above integral equation can be approximated as Li

k(xp) ≈ di(xp) + m

q=−m

wqφi(xp − axq)Li

k(xq)

Or, in matrix form, 𝐌i = (𝐉 − 𝚾i)−1𝐞i and 𝐍i = (𝐉 − 𝚾i)−1𝟐

Computing ∂𝐥𝐌𝐣

𝐥(𝟏) and ∂𝐥𝐍𝐣 𝐥(𝟏) Balance equation

Li

k(x) = di k(x) + ∫ k −k

φi(y − ax)Li

k(y)dy

Computing ∂𝐥𝐌𝐣

𝐥(𝟏) and ∂𝐥𝐍𝐣 𝐥(𝟏) Balance equation

Li

k(x) = di k(x) + ∫ k −k

φi(y − ax)Li

k(y)dy

Take derivative

Using Leibniz rule ∂kLi

k(x) = φi(x − ak)Li k(x) + φi(x + ak)Li k(−k) + ∫ k −k

φi(x − ay)Li

k(y)dy

∂kMi

k(x) = φi(x − ak)Mi k(x) + φi(x + ak)Mi k(−k) + ∫ k −k

φi(x − ay)Mi

k(y)dy

Computing ∂𝐥𝐌𝐣

𝐥(𝟏) and ∂𝐥𝐍𝐣 𝐥(𝟏) Balance equation

Li

k(x) = di k(x) + ∫ k −k

φi(y − ax)Li

k(y)dy

Take derivative

Using Leibniz rule ∂kLi

k(x) = φi(x − ak)Li k(x) + φi(x + ak)Li k(−k) + ∫ k −k

φi(x − ay)Li

k(y)dy

∂kMi

k(x) = φi(x − ak)Mi k(x) + φi(x + ak)Mi k(−k) + ∫ k −k

φi(x − ay)Mi

k(y)dy

Taking ratios, we get ∂kLi

k(x)

∂kMi

k(x) = Li k(k)

Mi

k(k)

slide-50
SLIDE 50

Remote estimation over CAN–(Mahajan)

13

How to compute value of information?

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

First simplification

Let fi

k denote the threshold policy with threshold k.

Defjne Di

k = lim T→∞

1 T 𝔽 [

T−1

t=0

(1 − Ui

t)di(Ei t)

] and Ni

k = lim T→∞

1 T 𝔽 [

T−1

t=0

Ui

t]

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

First simplification

Let fi

k denote the threshold policy with threshold k.

Defjne Di

k = lim T→∞

1 T 𝔽 [

T−1

t=0

(1 − Ui

t)di(Ei t)

] and Ni

k = lim T→∞

1 T 𝔽 [

T−1

t=0

Ui

t]

Then, Ji(fi

k) = Di k + λiNi

  • k. The policy is optimal if ∂kDi

k + λi∂kNi k = 0.

Therefore, VOIi(k) = −∂kDi

k

∂kNi

k

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Then, from renewal theory: Di

k = Li k(0)

Mi

k(0) and Ni k =

1 Mi

k(0) .

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Then, from renewal theory: Di

k = Li k(0)

Mi

k(0) and Ni k =

1 Mi

k(0) .

Therefore, VOIi(k) = Mi

k(0) ∂kLi k(0)

∂kMi

k(0) − Li k(0)

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Then, from renewal theory: Di

k = Li k(0)

Mi

k(0) and Ni k =

1 Mi

k(0) .

Therefore, VOIi(k) = Mi

k(0) ∂kLi k(0)

∂kMi

k(0) − Li k(0)

Need to compute Mi

k(0), Li k(0), ∂kMi k(0), ∂kLi k(0) to compute VOI.

Computing 𝐌𝐣

𝐥(𝟏) and 𝐍𝐣 𝐥(𝟏) Balance equation

Li

k(x) = di k(x) + ∫ k −k

φi(y − ax)Li

k(y)dy

(Fredholm integral eqn of the 2nd kind)

Computing 𝐌𝐣

𝐥(𝟏) and 𝐍𝐣 𝐥(𝟏) Balance equation

Li

k(x) = di k(x) + ∫ k −k

φi(y − ax)Li

k(y)dy

(Fredholm integral eqn of the 2nd kind)

Solution using quadrature method

Let {w−m, . . . , wm} and {x−m, . . . , xm} be the weights and abscissas for any quadrature rule of 2m + 1 points over [−k, k]. Then the above integral equation can be approximated as Li

k(xp) ≈ di(xp) + m

q=−m

wqφi(xp − axq)Li

k(xq)

Computing 𝐌𝐣

𝐥(𝟏) and 𝐍𝐣 𝐥(𝟏) Balance equation

Li

k(x) = di k(x) + ∫ k −k

φi(y − ax)Li

k(y)dy

(Fredholm integral eqn of the 2nd kind)

Solution using quadrature method

Let {w−m, . . . , wm} and {x−m, . . . , xm} be the weights and abscissas for any quadrature rule of 2m + 1 points over [−k, k]. Then the above integral equation can be approximated as Li

k(xp) ≈ di(xp) + m

q=−m

wqφi(xp − axq)Li

k(xq)

Or, in matrix form, 𝐌i = (𝐉 − 𝚾i)−1𝐞i

Computing 𝐌𝐣

𝐥(𝟏) and 𝐍𝐣 𝐥(𝟏) Balance equation

Li

k(x) = di k(x) + ∫ k −k

φi(y − ax)Li

k(y)dy

(Fredholm integral eqn of the 2nd kind)

Solution using quadrature method

Let {w−m, . . . , wm} and {x−m, . . . , xm} be the weights and abscissas for any quadrature rule of 2m + 1 points over [−k, k]. Then the above integral equation can be approximated as Li

k(xp) ≈ di(xp) + m

q=−m

wqφi(xp − axq)Li

k(xq)

Or, in matrix form, 𝐌i = (𝐉 − 𝚾i)−1𝐞i and 𝐍i = (𝐉 − 𝚾i)−1𝟐

Computing ∂𝐥𝐌𝐣

𝐥(𝟏) and ∂𝐥𝐍𝐣 𝐥(𝟏) Balance equation

Li

k(x) = di k(x) + ∫ k −k

φi(y − ax)Li

k(y)dy

Computing ∂𝐥𝐌𝐣

𝐥(𝟏) and ∂𝐥𝐍𝐣 𝐥(𝟏) Balance equation

Li

k(x) = di k(x) + ∫ k −k

φi(y − ax)Li

k(y)dy

Take derivative

Using Leibniz rule ∂kLi

k(x) = φi(x − ak)Li k(x) + φi(x + ak)Li k(−k) + ∫ k −k

φi(x − ay)Li

k(y)dy

∂kMi

k(x) = φi(x − ak)Mi k(x) + φi(x + ak)Mi k(−k) + ∫ k −k

φi(x − ay)Mi

k(y)dy

Computing ∂𝐥𝐌𝐣

𝐥(𝟏) and ∂𝐥𝐍𝐣 𝐥(𝟏) Balance equation

Li

k(x) = di k(x) + ∫ k −k

φi(y − ax)Li

k(y)dy

Take derivative

Using Leibniz rule ∂kLi

k(x) = φi(x − ak)Li k(x) + φi(x + ak)Li k(−k) + ∫ k −k

φi(x − ay)Li

k(y)dy

∂kMi

k(x) = φi(x − ak)Mi k(x) + φi(x + ak)Mi k(−k) + ∫ k −k

φi(x − ay)Mi

k(y)dy

Taking ratios, we get ∂kLi

k(x)

∂kMi

k(x) = Li k(k)

Mi

k(k)

Computing ∂𝐥𝐌𝐣

𝐥(𝟏) and ∂𝐥𝐍𝐣 𝐥(𝟏) Balance equation

Li

k(x) = di k(x) + ∫ k −k

φi(y − ax)Li

k(y)dy

Take derivative

Using Leibniz rule ∂kLi

k(x) = φi(x − ak)Li k(x) + φi(x + ak)Li k(−k) + ∫ k −k

φi(x − ay)Li

k(y)dy

∂kMi

k(x) = φi(x − ak)Mi k(x) + φi(x + ak)Mi k(−k) + ∫ k −k

φi(x − ay)Mi

k(y)dy

Taking ratios, we get ∂kLi

k(x)

∂kMi

k(x) = Li k(k)

Mi

k(k)

Final expression

VOIi(k) = 𝐍i 𝐌i

m

𝐍i

m

− 𝐌i

0,

where 𝐌i = (𝐉 − 𝚾i)−1𝐞i and 𝐍i = (𝐉 − 𝚾i)−1𝟐 .

slide-51
SLIDE 51

Remote estimation over CAN–(Mahajan)

13

Numerical example

Scenarios

n sensors, each observing a Gauss-Markov process. Scenario A 50 homogeneous sensors with (ai, σi) = (1, 1). Scenario B 25 sensors with (ai, σi) = (1, 1) and 25 sensors with (ai, σi) = (1, 5). Scenario C 20 sensors (ai, σi) = (1, 1); 15 with (1, 5); 15 with (1, 10).

slide-52
SLIDE 52

Remote estimation over CAN–(Mahajan)

13

Numerical example

Scenarios

n sensors, each observing a Gauss-Markov process. Scenario A 50 homogeneous sensors with (ai, σi) = (1, 1). Scenario B 25 sensors with (ai, σi) = (1, 1) and 25 sensors with (ai, σi) = (1, 5). Scenario C 20 sensors (ai, σi) = (1, 1); 15 with (1, 5); 15 with (1, 10).

Comparison

TDMA Sensors transmit periodically ERR Sensor with highest error transmits VOI Sensor with the highest VOI transmits

slide-53
SLIDE 53

Remote estimation over CAN–(Mahajan)

13

Numerical example

Scenarios

n sensors, each observing a Gauss-Markov process. Scenario A 50 homogeneous sensors with (ai, σi) = (1, 1). Scenario B 25 sensors with (ai, σi) = (1, 1) and 25 sensors with (ai, σi) = (1, 5). Scenario C 20 sensors (ai, σi) = (1, 1); 15 with (1, 5); 15 with (1, 10).

Comparison

TDMA Sensors transmit periodically ERR Sensor with highest error transmits VOI Sensor with the highest VOI transmits ERR VOI 2 4 6 8 ERR VOI 20 40 60 80 100 ERR VOI 100 200 Scenario A Scenario B Scenario C

slide-54
SLIDE 54

Remote estimation over CAN–(Mahajan)

14

Summary

slide-55
SLIDE 55

Remote estimation over CAN–(Mahajan)

14

Summary

System Model

Sensors

n sensors indexed by N = {1, . . . , n}. Xi

t+1 = aiXi t + Wi t,

ai, Xi

t, Wi t ∈ ℝ,

Wi

t ∼ φi(⋅).

Assumptions

The observation processes across sensors are independent. The noise process is independent across time (and independent of initial state) The density φi(⋅) is even and unimodal.

Network

Received packet Yi

t =

{ XI

t,

if sensor i has highest priority 𝔉,

  • therwise

Receivers

Estimate ˆ Xi

t =

{ Yi

t,

if Yi

t ≠ 𝔉

ai ˆ Xi

t−1,

if Yi

t = 𝔉

Distortion di(Xi

t − ˆ

Xi

t), where di(⋅) is an even and increasing function.

Control Area Network Control Area Network ⋮ ⋮ Receiver 1 Receiver n Sensor 1 Sensor n (Z1

t, X1 t)

(Zn

t , Xn t )

Y1

t

Yn

t

ˆ X1

t

ˆ Xn

t

X1

t

Xn

t

slide-56
SLIDE 56

Remote estimation over CAN–(Mahajan)

14

Summary

System Model

Sensors

n sensors indexed by N = {1, . . . , n}. Xi

t+1 = aiXi t + Wi t,

ai, Xi

t, Wi t ∈ ℝ,

Wi

t ∼ φi(⋅).

Assumptions

The observation processes across sensors are independent. The noise process is independent across time (and independent of initial state) The density φi(⋅) is even and unimodal.

Network

Received packet Yi

t =

{ XI

t,

if sensor i has highest priority 𝔉,

  • therwise

Receivers

Estimate ˆ Xi

t =

{ Yi

t,

if Yi

t ≠ 𝔉

ai ˆ Xi

t−1,

if Yi

t = 𝔉

Distortion di(Xi

t − ˆ

Xi

t), where di(⋅) is an even and increasing function.

Control Area Network Control Area Network ⋮ ⋮ Receiver 1 Receiver n Sensor 1 Sensor n (Z1

t, X1 t)

(Zn

t , Xn t )

Y1

t

Yn

t

ˆ X1

t

ˆ Xn

t

X1

t

Xn

t

Defining the value of information

Value of Information (VOI)

The amount of money someone is willing to pay to access that information.

VOI for remote estimation

Suppose that there is a single sensor, say i, and a dedicated communication channel is available. The sensor has to pay an access fee λi each time it uses the channel. Let Ui

t ∈ {0, 1} denote the sensor’s decision.

Then, the error process is Ei

t+1 =

{ Wi

t,

if Ui

t = 1

aiEi

t + Wi t

if Ui

t = 0

Objective

min lim

T→∞

1 T 𝔽 [

T−1

t=0 [λiUi + (1 − Ui)di(Ei t)]]

slide-57
SLIDE 57

Remote estimation over CAN–(Mahajan)

14

Summary

System Model

Sensors

n sensors indexed by N = {1, . . . , n}. Xi

t+1 = aiXi t + Wi t,

ai, Xi

t, Wi t ∈ ℝ,

Wi

t ∼ φi(⋅).

Assumptions

The observation processes across sensors are independent. The noise process is independent across time (and independent of initial state) The density φi(⋅) is even and unimodal.

Network

Received packet Yi

t =

{ XI

t,

if sensor i has highest priority 𝔉,

  • therwise

Receivers

Estimate ˆ Xi

t =

{ Yi

t,

if Yi

t ≠ 𝔉

ai ˆ Xi

t−1,

if Yi

t = 𝔉

Distortion di(Xi

t − ˆ

Xi

t), where di(⋅) is an even and increasing function.

Control Area Network Control Area Network ⋮ ⋮ Receiver 1 Receiver n Sensor 1 Sensor n (Z1

t, X1 t)

(Zn

t , Xn t )

Y1

t

Yn

t

ˆ X1

t

ˆ Xn

t

X1

t

Xn

t

Defining the value of information

Value of Information (VOI)

The amount of money someone is willing to pay to access that information.

VOI for remote estimation

Suppose that there is a single sensor, say i, and a dedicated communication channel is available. The sensor has to pay an access fee λi each time it uses the channel. Let Ui

t ∈ {0, 1} denote the sensor’s decision.

Then, the error process is Ei

t+1 =

{ Wi

t,

if Ui

t = 1

aiEi

t + Wi t

if Ui

t = 0

Objective

min lim

T→∞

1 T 𝔽 [

T−1

t=0 [λiUi + (1 − Ui)di(Ei t)]]

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

First simplification

Let fi

k denote the threshold policy with threshold k.

Defjne Di

k = lim T→∞

1 T 𝔽 [

T−1

t=0

(1 − Ui

t)di(Ei t)

] and Ni

k = lim T→∞

1 T 𝔽 [

T−1

t=0

Ui

t]

Then, Ji(fi

k) = Di k + λiNi

  • k. The policy is optimal if ∂kDi

k + λi∂kNi k = 0.

Therefore, VOIi(k) = −∂kDi

k

∂kNi

k

slide-58
SLIDE 58

Remote estimation over CAN–(Mahajan)

14

Summary

System Model

Sensors

n sensors indexed by N = {1, . . . , n}. Xi

t+1 = aiXi t + Wi t,

ai, Xi

t, Wi t ∈ ℝ,

Wi

t ∼ φi(⋅).

Assumptions

The observation processes across sensors are independent. The noise process is independent across time (and independent of initial state) The density φi(⋅) is even and unimodal.

Network

Received packet Yi

t =

{ XI

t,

if sensor i has highest priority 𝔉,

  • therwise

Receivers

Estimate ˆ Xi

t =

{ Yi

t,

if Yi

t ≠ 𝔉

ai ˆ Xi

t−1,

if Yi

t = 𝔉

Distortion di(Xi

t − ˆ

Xi

t), where di(⋅) is an even and increasing function.

Control Area Network Control Area Network ⋮ ⋮ Receiver 1 Receiver n Sensor 1 Sensor n (Z1

t, X1 t)

(Zn

t , Xn t )

Y1

t

Yn

t

ˆ X1

t

ˆ Xn

t

X1

t

Xn

t

Defining the value of information

Value of Information (VOI)

The amount of money someone is willing to pay to access that information.

VOI for remote estimation

Suppose that there is a single sensor, say i, and a dedicated communication channel is available. The sensor has to pay an access fee λi each time it uses the channel. Let Ui

t ∈ {0, 1} denote the sensor’s decision.

Then, the error process is Ei

t+1 =

{ Wi

t,

if Ui

t = 1

aiEi

t + Wi t

if Ui

t = 0

Objective

min lim

T→∞

1 T 𝔽 [

T−1

t=0 [λiUi + (1 − Ui)di(Ei t)]]

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

First simplification

Let fi

k denote the threshold policy with threshold k.

Defjne Di

k = lim T→∞

1 T 𝔽 [

T−1

t=0

(1 − Ui

t)di(Ei t)

] and Ni

k = lim T→∞

1 T 𝔽 [

T−1

t=0

Ui

t]

Then, Ji(fi

k) = Di k + λiNi

  • k. The policy is optimal if ∂kDi

k + λi∂kNi k = 0.

Therefore, VOIi(k) = −∂kDi

k

∂kNi

k

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Then, from renewal theory: Di

k = Li k(0)

Mi

k(0) and Ni k =

1 Mi

k(0) .

Therefore, VOIi(k) = Mi

k(0) ∂kLi k(0)

∂kMi

k(0) − Li k(0)

Need to compute Mi

k(0), Li k(0), ∂kMi k(0), ∂kLi k(0) to compute VOI.

slide-59
SLIDE 59

Remote estimation over CAN–(Mahajan)

14

Summary

System Model

Sensors

n sensors indexed by N = {1, . . . , n}. Xi

t+1 = aiXi t + Wi t,

ai, Xi

t, Wi t ∈ ℝ,

Wi

t ∼ φi(⋅).

Assumptions

The observation processes across sensors are independent. The noise process is independent across time (and independent of initial state) The density φi(⋅) is even and unimodal.

Network

Received packet Yi

t =

{ XI

t,

if sensor i has highest priority 𝔉,

  • therwise

Receivers

Estimate ˆ Xi

t =

{ Yi

t,

if Yi

t ≠ 𝔉

ai ˆ Xi

t−1,

if Yi

t = 𝔉

Distortion di(Xi

t − ˆ

Xi

t), where di(⋅) is an even and increasing function.

Control Area Network Control Area Network ⋮ ⋮ Receiver 1 Receiver n Sensor 1 Sensor n (Z1

t, X1 t)

(Zn

t , Xn t )

Y1

t

Yn

t

ˆ X1

t

ˆ Xn

t

X1

t

Xn

t

Defining the value of information

Value of Information (VOI)

The amount of money someone is willing to pay to access that information.

VOI for remote estimation

Suppose that there is a single sensor, say i, and a dedicated communication channel is available. The sensor has to pay an access fee λi each time it uses the channel. Let Ui

t ∈ {0, 1} denote the sensor’s decision.

Then, the error process is Ei

t+1 =

{ Wi

t,

if Ui

t = 1

aiEi

t + Wi t

if Ui

t = 0

Objective

min lim

T→∞

1 T 𝔽 [

T−1

t=0 [λiUi + (1 − Ui)di(Ei t)]]

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

First simplification

Let fi

k denote the threshold policy with threshold k.

Defjne Di

k = lim T→∞

1 T 𝔽 [

T−1

t=0

(1 − Ui

t)di(Ei t)

] and Ni

k = lim T→∞

1 T 𝔽 [

T−1

t=0

Ui

t]

Then, Ji(fi

k) = Di k + λiNi

  • k. The policy is optimal if ∂kDi

k + λi∂kNi k = 0.

Therefore, VOIi(k) = −∂kDi

k

∂kNi

k

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Then, from renewal theory: Di

k = Li k(0)

Mi

k(0) and Ni k =

1 Mi

k(0) .

Therefore, VOIi(k) = Mi

k(0) ∂kLi k(0)

∂kMi

k(0) − Li k(0)

Need to compute Mi

k(0), Li k(0), ∂kMi k(0), ∂kLi k(0) to compute VOI.

Computing 𝐌𝐣

𝐥(𝟏) and 𝐍𝐣 𝐥(𝟏) Balance equation

Li

k(x) = di k(x) + ∫ k −k

φi(y − ax)Li

k(y)dy

(Fredholm integral eqn of the 2nd kind)

Solution using quadrature method

Let {w−m, . . . , wm} and {x−m, . . . , xm} be the weights and abscissas for any quadrature rule of 2m + 1 points over [−k, k]. Then the above integral equation can be approximated as Li

k(xp) ≈ di(xp) + m

q=−m

wqφi(xp − axq)Li

k(xq)

Or, in matrix form, 𝐌i = (𝐉 − 𝚾i)−1𝐞i and 𝐍i = (𝐉 − 𝚾i)−1𝟐

slide-60
SLIDE 60

Remote estimation over CAN–(Mahajan)

14

Summary

System Model

Sensors

n sensors indexed by N = {1, . . . , n}. Xi

t+1 = aiXi t + Wi t,

ai, Xi

t, Wi t ∈ ℝ,

Wi

t ∼ φi(⋅).

Assumptions

The observation processes across sensors are independent. The noise process is independent across time (and independent of initial state) The density φi(⋅) is even and unimodal.

Network

Received packet Yi

t =

{ XI

t,

if sensor i has highest priority 𝔉,

  • therwise

Receivers

Estimate ˆ Xi

t =

{ Yi

t,

if Yi

t ≠ 𝔉

ai ˆ Xi

t−1,

if Yi

t = 𝔉

Distortion di(Xi

t − ˆ

Xi

t), where di(⋅) is an even and increasing function.

Control Area Network Control Area Network ⋮ ⋮ Receiver 1 Receiver n Sensor 1 Sensor n (Z1

t, X1 t)

(Zn

t , Xn t )

Y1

t

Yn

t

ˆ X1

t

ˆ Xn

t

X1

t

Xn

t

Defining the value of information

Value of Information (VOI)

The amount of money someone is willing to pay to access that information.

VOI for remote estimation

Suppose that there is a single sensor, say i, and a dedicated communication channel is available. The sensor has to pay an access fee λi each time it uses the channel. Let Ui

t ∈ {0, 1} denote the sensor’s decision.

Then, the error process is Ei

t+1 =

{ Wi

t,

if Ui

t = 1

aiEi

t + Wi t

if Ui

t = 0

Objective

min lim

T→∞

1 T 𝔽 [

T−1

t=0 [λiUi + (1 − Ui)di(Ei t)]]

Naive method

For a given λi, fjnd ki(λi) by numerically solving the dynamic program. VOIi(e) can be computed by doing a binary search of λi until ki(λi) = |e|. This method is extremely ineffjcient because solving DP is hard.

First simplification

Let fi

k denote the threshold policy with threshold k.

Defjne Di

k = lim T→∞

1 T 𝔽 [

T−1

t=0

(1 − Ui

t)di(Ei t)

] and Ni

k = lim T→∞

1 T 𝔽 [

T−1

t=0

Ui

t]

Then, Ji(fi

k) = Di k + λiNi

  • k. The policy is optimal if ∂kDi

k + λi∂kNi k = 0.

Therefore, VOIi(k) = −∂kDi

k

∂kNi

k

Computing ∂𝐥𝐄𝐣

𝐥 and ∂𝐥𝐎𝐣 𝐥 Renewal relationships

Let τ denote the stopping time of the fjrst transmission. Defjne Li

k(x) = 𝔽

[

τ−1

t=0

d(Ei

t)

| Ei

0 = x

] and Mi

k(x) = 𝔽 [τ | Ei 0 = x].

Then, from renewal theory: Di

k = Li k(0)

Mi

k(0) and Ni k =

1 Mi

k(0) .

Therefore, VOIi(k) = Mi

k(0) ∂kLi k(0)

∂kMi

k(0) − Li k(0)

Need to compute Mi

k(0), Li k(0), ∂kMi k(0), ∂kLi k(0) to compute VOI.

Computing 𝐌𝐣

𝐥(𝟏) and 𝐍𝐣 𝐥(𝟏) Balance equation

Li

k(x) = di k(x) + ∫ k −k

φi(y − ax)Li

k(y)dy

(Fredholm integral eqn of the 2nd kind)

Solution using quadrature method

Let {w−m, . . . , wm} and {x−m, . . . , xm} be the weights and abscissas for any quadrature rule of 2m + 1 points over [−k, k]. Then the above integral equation can be approximated as Li

k(xp) ≈ di(xp) + m

q=−m

wqφi(xp − axq)Li

k(xq)

Or, in matrix form, 𝐌i = (𝐉 − 𝚾i)−1𝐞i and 𝐍i = (𝐉 − 𝚾i)−1𝟐

Computing ∂𝐥𝐌𝐣

𝐥(𝟏) and ∂𝐥𝐍𝐣 𝐥(𝟏) Balance equation

Li

k(x) = di k(x) + ∫ k −k

φi(y − ax)Li

k(y)dy

Take derivative

Using Leibniz rule ∂kLi

k(x) = φi(x − ak)Li k(x) + φi(x + ak)Li k(−k) + ∫ k −k

φi(x − ay)Li

k(y)dy

∂kMi

k(x) = φi(x − ak)Mi k(x) + φi(x + ak)Mi k(−k) + ∫ k −k

φi(x − ay)Mi

k(y)dy

Taking ratios, we get ∂kLi

k(x)

∂kMi

k(x) = Li k(k)

Mi

k(k)

Final expression

VOIi(k) = 𝐍i 𝐌i

m

𝐍i

m

− 𝐌i

0,

where 𝐌i = (𝐉 − 𝚾i)−1𝐞i and 𝐍i = (𝐉 − 𝚾i)−1𝟐 .