CogNet – Architectural foundation for ex-perimental cognitive radio networksDipankar Raychaudhuri, Joseph B. Evans, Srinivasan Seshan

2011.4.11Sin-choo Kim

sckim@mmlab.snu.ac.kr

/ 15

Introduction Architectural foundation◦Global control plane◦PHY adaptation and network coding◦Spectrum coordination protocols◦Radio autoconfiguration protocols◦Flexible MAC layer◦Network layer protocols

Conclusion

2

Contents

/ 15

Cognitive (in Webster) ◦Applying the experience gathered in one place by

one being to actions by another being elsewhere

Cognitive network◦a network with a cognitive process that can

perceive current network conditions, plan, de-cide, act on those conditions, learn from the consequences of its actions, all while following end-to-end goals

3

Introduction

/ 15

Cognitive network

4

Introduction

Network layer

MAC layer

PHY layer

/ 15

Global control plane PHY adaptation and network coding Spectrum coordination protocols Radio autoconfiguration protocols Flexible MAC layer Network layer protocols

5

Architectural foundation

/ 15

Global control plane◦Cross layer network management overlay◦Monitor, configure and adapt the data plane module

6

Global control plane(1/2)

/ 15

Provided functions◦ Initial radio bootstrapping

Rebroadcast control packets, providing global aware-ness to all cognitive radios

◦Service discovery function Edge of the service band Dedicated portion of a TDMA frame

7

Global control plane(2/2)

/ 15

Network coding◦Collaborate with each other to recombine several input

packets into one or several output packets

Main benefits◦Throughput improvements◦ Increased robustness

Require GCP support ◦Path establishment

8

PHY adaptation and network coding

2 + 2 = 4

2 + 1 = 3

/ 15

Agile wideband radio◦ Transmitters scan and choose their frequency band

Reactive control◦ Seek equilibrium resource allocation without explicit coordination◦ Control rate and power

Common spectrum coordination channel(CSCC)◦ Each node uses beacons containing spectrum usage information

Spectrum server◦ Coordinated spectrum usages by centralized spectrum server

9

Spectrum coordination protocols

/ 15

In bootstrapping process, node aware ◦Network status◦Surrounding nodes

To conduct those process◦Obtaining PHY parameters, reachability◦Negotiate with existing sub-networks for name/service

discovery or performance optimization

10

Radio autoconfiguration protocols

/ 15

Dynamically changes MAC protocols◦ ex) RTS/CTS

Where collision rarely happened, RTS/CTS is overhead

Compatible MAC Protocol◦Ensures that a pair of node can communicate directly

with each other. Nodes that are part of the same constellation must use com-

patible MAC protocols Independent constellations may make independent optimiza-

tion decisions

11

Flexible MAC layer

/ 15

Overlay-based mechanisms Supernode◦Serve as a gateway between local network layers as

well as to the future Internet and its IP-based and over-lay-based networks.

12

Network layer protocols(1/4)

/ 15

Naming and service discovery

13

Network layer protocols(2/4)

ID

/ 15

Cross-layer aware routing◦Node can obtain information about the application traf-

fic, specified policies, link capabilities and so on◦This information will be exposed via GCP

Forwarding incentives in cognitive network◦Encourage forwarding others’ packets in ad hoc network

14

Network layer protocols(3/4)

/ 15

CogNet provides the way to integrate cognitive networks into global Internet

To apply the information collected, CogNet changes three layers PHY, MAC, network layer and make be possible to communicate by using cross-layer

15

Conclusion

Thank you