Remote estimation over control area networks Aditya Mahajan McGill - - PowerPoint PPT Presentation
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
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 . . .
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
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.
Remote estimation over CAN–(Mahajan)
4
Background
Remote estimation over CAN–(Mahajan)
4
Background
Arbitration in Control Area Network
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.
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.
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.
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
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.
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.
Remote estimation over CAN–(Mahajan)
6
Model and Problem Formulation
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
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
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
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
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
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)
]
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.
Remote estimation over CAN–(Mahajan)
9
What is Value of Information?
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
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)
]
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.
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.
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
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)]]
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.
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 + ∫
ℝ
φi(w)vi(w)dw, di(e) + ∫
ℝ
φi(w)vi(ae + w)dw}
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 + ∫
ℝ
φi(w)vi(w)dw, di(e) + ∫
ℝ
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 + ∫
ℝ
φi(w)vi(w)dw, di(e) + ∫
ℝ
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.
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 + ∫
ℝ
φi(w)vi(w)dw, di(e) + ∫
ℝ
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 + ∫
ℝ
φi(w)vi(w)dw, di(e) + ∫
ℝ
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 + ∫
ℝ
φi(w)vi(w)dw, di(e) + ∫
ℝ
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 + ∫
ℝ
φi(w)vi(w)dw = di(e) + ∫
ℝ
φi(w)vi(ae + w)dw
Proof relies on stochastic monot-
- nicity, stochastic dominance, and
submodularity.
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 + ∫
ℝ
φi(w)vi(w)dw, di(e) + ∫
ℝ
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 + ∫
ℝ
φi(w)vi(w)dw, di(e) + ∫
ℝ
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 + ∫
ℝ
φi(w)vi(w)dw, di(e) + ∫
ℝ
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 + ∫
ℝ
φi(w)vi(w)dw = di(e) + ∫
ℝ
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 + ∫
ℝ
φi(w)vi(w)dw, di(e) + ∫
ℝ
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 + ∫
ℝ
φi(w)vi(w)dw = di(e) + ∫
ℝ
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|}
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 + ∫
ℝ
φi(w)vi(w)dw, di(e) + ∫
ℝ
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 + ∫
ℝ
φi(w)vi(w)dw, di(e) + ∫
ℝ
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 + ∫
ℝ
φi(w)vi(w)dw, di(e) + ∫
ℝ
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 + ∫
ℝ
φi(w)vi(w)dw = di(e) + ∫
ℝ
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 + ∫
ℝ
φi(w)vi(w)dw, di(e) + ∫
ℝ
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 + ∫
ℝ
φi(w)vi(w)dw = di(e) + ∫
ℝ
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|}
Remote estimation over CAN–(Mahajan)
13
How to compute value of information?
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.
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]
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
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].
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) .
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)
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.
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)
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)
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
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
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
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
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)
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 .
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).
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
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
Remote estimation over CAN–(Mahajan)
14
Summary
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
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)]]
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
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.
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
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 .