Building Link-Layer Protocols in a Lego-like Fashion Andr Puschmann - - PowerPoint PPT Presentation

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Building Link-Layer Protocols in a Lego-like Fashion Andr Puschmann - - PowerPoint PPT Presentation

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Building Link-Layer Protocols in a Lego-like Fashion Andr Puschmann FOSDEM14 February 2nd, 2014 Integrated Communication Integrated Communication International Graduate School on International Graduate School on Systems Group Systems

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Integrated Communication Systems Group International Graduate School on Mobile Communications

Building Link-Layer Protocols in a Lego-like Fashion

André Puschmann

FOSDEM’14 February 2nd, 2014

Integrated Communication Systems Group International Graduate School on Mobile Communications

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Introduction State of the Art Architecture Practical Examples Summary

Outline

1

Introduction

2

State of the Art

3

Component-based Link Layer Protocols

4

Practical Examples

5

Summary

André Puschmann Integrated Communication Systems Group http://www.tu-ilmenau.de/ics FOSDEM’14 February 2nd, 2014 2

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Introduction State of the Art Architecture Practical Examples Summary

Motivation

Power Time F r e q u e n c y

PHY: Flexibility mostly here, e.g. Antennas Waveforms Spectrum sensing Higher layer: Mostly individual and application specific, e.g. Energy-efficiency Delay tolerant networking Cognitive Radio (CR) Dynamic Spectrum Access

Key question:

Can higher layer components benefit from flexibility, too?

André Puschmann Integrated Communication Systems Group http://www.tu-ilmenau.de/ics FOSDEM’14 February 2nd, 2014 3

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Introduction State of the Art Architecture Practical Examples Summary

The CR link layer: What remains? What changes?

CR 1 CR 2 CR 3

Requirements: Basic link layer functions Management of PHY resources Application specific, e.g.: Link establishment Link maintenance Challenges: How to address heterogeneous system requirements? Data transfer vs management functions? How to facilitate reuse of existing protocols?

André Puschmann Integrated Communication Systems Group http://www.tu-ilmenau.de/ics FOSDEM’14 February 2nd, 2014 4

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Introduction State of the Art Architecture Practical Examples Summary

State of the Art

Rendezvous Mobility Link Layer + MAC

PHY

Higher Layer

Link Layer

Approaches: Stand alone or extended protocols ⊖ Limited feature set ⊖ Monolithic design, tight integration Flexible MACs with fine-grained components ⊖ Off-the-shelf 802.11 HW or FPGA-only Flexible MACs with coarse-grained components Conclusion: Protocols complex and difficult to implement/maintain Reduced re-usability due to tight integration Mix of data transmission and management functionality

André Puschmann Integrated Communication Systems Group http://www.tu-ilmenau.de/ics FOSDEM’14 February 2nd, 2014 5

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Introduction State of the Art Architecture Practical Examples Summary

Lego-like Link Layer Architecture

Legacy Architecture:

Rendezvous Mobility Link Layer + MAC

PHY

Higher Layer

Link Layer

Component-based Architecture:

Higher Layer Controller

Link Layer

Rendezvous LL+MAC Mobility

PHY

Logical components: Core blocks: → Basic LL+MAC Optional apps: → Rendezvous → Spectrum Mobility .. Controller: → Manage PHY capabilities → FSM to model dynamics → Events to allow interactions

André Puschmann Integrated Communication Systems Group http://www.tu-ilmenau.de/ics FOSDEM’14 February 2nd, 2014 6

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Introduction State of the Art Architecture Practical Examples Summary

Details of Link-Layer Architecture

Frame Mux MAC Rendezvous Mobility User Applications Controller

EFCP: Error- and Flow-Control Protocol PHY Link Layer Media dependent

EFCP EFCP EFCP MAC

Data Control

Frame Mux

Decoupled Same Interfaces PHY Capabilities Application specific Generic André Puschmann Integrated Communication Systems Group http://www.tu-ilmenau.de/ics FOSDEM’14 February 2nd, 2014 7

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Introduction State of the Art Architecture Practical Examples Summary

Let’s Play Protocol Lego

Rendezvous

Blind (Random, JS, ..) Coordinator- assisted

Basic Link Layer

Stop and Wait Block Acks Flow ID with prios

MAC

Pure Aloha Soft/FPGA CSMA Simple TDMA

Mobility

Individual Coordinator- assisted Cluster-based

André Puschmann Integrated Communication Systems Group http://www.tu-ilmenau.de/ics FOSDEM’14 February 2nd, 2014 8

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Introduction State of the Art Architecture Practical Examples Summary

How does the protocol interaction work?

Business Logic FSM C++ Implementation FllFsmBase Code Generator FSM XML Model FllController Library

<state name="AgileReceiver"> <transition event="EvStop" nextState="End"/> <state name="Unconnected"> <transition event="EvStart" nextState="FindNextChannel"/> <transition event="EvFrameReceived" nextState="Connected"/> <state name="FindNextChannel"> <onEntry> <action>fsm.FindNextChannel()</action> </onEntry> <transition event="EvChannelFound" nextState="ReconfigureRadio"> <action>fsm.reconfigureChannel(channel)</action> </transition> </state> <state name="ReconfigureRadio"> <transition event="EvReconfDone" nextState="WaitForFrame"/> </state> .. <state/>

[1] StateBuilderCpp, http://www.stateforge.com/

André Puschmann Integrated Communication Systems Group http://www.tu-ilmenau.de/ics FOSDEM’14 February 2nd, 2014 9

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Introduction State of the Art Architecture Practical Examples Summary

Database-assisted Dynamic Spectrum Access

Features: Spectrum opportunity detection Dynamic channel allocation Database for predictive PU modelling Link adaptation and PU resilience

  • A. Puschmann, et al., “Database-assisted Coordinator-based Spectrum Mobility in Cognitive Radio

Ad-hoc Networks"“, 10th International Symposium on Wireless Communication Systems (ISWCS), Ilmenau, Germany, August 2013.

André Puschmann Integrated Communication Systems Group http://www.tu-ilmenau.de/ics FOSDEM’14 February 2nd, 2014 10

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Introduction State of the Art Architecture Practical Examples Summary

Low-cost, Frequency-agile SDR Networking

Ubuntu Touch Iris

2,09250 GHz 2,09450 GHz 2,09650 GHz

Python App Iris QML Video

ZMQ AgileRx FSM LiquidDsp OFDM .. UDP Frame Detector André Puschmann Integrated Communication Systems Group http://www.tu-ilmenau.de/ics FOSDEM’14 February 2nd, 2014 11

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Introduction State of the Art Architecture Practical Examples Summary

Summary

Flexibility in higher layers?

Generic, extensible Core protocol(s) Problem specific Link Layer Apps

Wide application range Protocol reuse Separation of Transfer/management

Interaction through Events FSM Controller

André Puschmann Integrated Communication Systems Group http://www.tu-ilmenau.de/ics FOSDEM’14 February 2nd, 2014 12

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Questions, comments?

andre.puschmann@tu-ilmenau.de Ilmenau University of Technology, Germany Visit us: http://www.tu-ilmenau.de/ics

André Puschmann Integrated Communication Systems Group http://www.tu-ilmenau.de/ics FOSDEM’14 February 2nd, 2014 13

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Sources

Rohde & Schwartz Spectrum Analyser image http://www.rohde-schwarz.de/product/FSVR.html Nexus 7 image http://en.wikipedia.org/wiki/File: Front_view_of_Nexus_7_(cropped).png RTL-SDR http://ecx.images-amazon.com/images/I/41-RmZAq7EL._SY300_.jpg BladeRF image http://www.nuand.com/ Thinkpad image http://en.wikipedia.org/wiki/File:Thinkpad-x61-tablet.jpg

André Puschmann Integrated Communication Systems Group http://www.tu-ilmenau.de/ics FOSDEM’14 February 2nd, 2014 14