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Cognitive Radio Communications and Networks: Principles and Practice By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009) 1 Chapter 9 Fundamentals.

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Presentation on theme: "Cognitive Radio Communications and Networks: Principles and Practice By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009) 1 Chapter 9 Fundamentals."— Presentation transcript:

1 Cognitive Radio Communications and Networks: Principles and Practice By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009) 1 Chapter 9 Fundamentals of Communication Networks

2 Cognitive Radio Communications and Networks: Principles and Practice By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009) Communication Network Architecture Communication devices Network nodes Communication links

3 Cognitive Radio Communications and Networks: Principles and Practice By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009) Protocol Architecture Break communication task down into subtasks Divide-and-conquer approach Hierarchical layers Protocols Define subtask operation within a layer TCP/IP protocols

4 Cognitive Radio Communications and Networks: Principles and Practice By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009) Switching Technologies Circuit switching Circuit establishment Data transfer Circuit termination

5 Cognitive Radio Communications and Networks: Principles and Practice By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009) Switching Technologies Packet switching Store-and-forward Network resources allocated on-demand

6 Cognitive Radio Communications and Networks: Principles and Practice By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009) Switching Technologies Virtual circuit switching Combining features of circuit switching and packet switching Virtual circuit pre-established Link bandwidth shared efficiently

7 Cognitive Radio Communications and Networks: Principles and Practice By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009) Encapsulation and Multiplexing

8 Cognitive Radio Communications and Networks: Principles and Practice By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009) Naming and Addressing Domain name Domain Name System (DNS) Port number Well-known port numbers Ephemeral port numbers

9 Cognitive Radio Communications and Networks: Principles and Practice By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009) Naming and Addressing IP address Subnetting Socket: combination of an IP address and a port number Medium Access Control (MAC) address

10 Cognitive Radio Communications and Networks: Principles and Practice By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009) Multiple Access Media shared in a broadcast network Rules for hosts to access the media Media Access Control (MAC)

11 Cognitive Radio Communications and Networks: Principles and Practice By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009) Routing and Forwarding Network layer function Maintaining network topology information Routing table Forwarding packets Packets forwarded hop-by-hop

12 Cognitive Radio Communications and Networks: Principles and Practice By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009) Congestion Control and Flow Control Congestion control Router congestion Flow control Fast transmitter and slow receiver

13 Cognitive Radio Communications and Networks: Principles and Practice By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009) Error Control Checksum in TCP/IP Cyclic redundancy check (CRC) in Ethernet Sequence numbers to detect lost packets

14 Cognitive Radio Communications and Networks: Principles and Practice By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009) New Challenges in Wireless Networks Wireless transmissions Different concept of communication link Coupled channels Capacity limited by SINR Mobility Handoff in infrastructure-based wireless networks Rerouting in infrastructureless wireless networks Energy efficiency Significant impact in every layer

15 Cognitive Radio Communications and Networks: Principles and Practice By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009) Mobility Modeling The Random Waypoint Model

16 Cognitive Radio Communications and Networks: Principles and Practice By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009) Mobility Modeling Speed distribution Average speed Location distribution

17 Cognitive Radio Communications and Networks: Principles and Practice By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009) Perfect Simulation

18 Cognitive Radio Communications and Networks: Principles and Practice By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009) Power Control and Multiuser Diversity Uplink of a infrastructure-based wireless network Received signal at the base station is Frequency flat Reyleigh fading Objective

19 Cognitive Radio Communications and Networks: Principles and Practice By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009) Power Control and Multiuser Diversity No power control Perfect power control Optimal power control

20 Cognitive Radio Communications and Networks: Principles and Practice By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009) Power Control and Multiuser Diversity

21 Cognitive Radio Communications and Networks: Principles and Practice By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009) Multiple Access Schemes Classification of multi-access schemes

22 Cognitive Radio Communications and Networks: Principles and Practice By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009) Polling Queueing system with one server and m stations Finite buffer and infinite buffer

23 Cognitive Radio Communications and Networks: Principles and Practice By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009) Polling Service policies Limited service Exhaustive service Gated service

24 Cognitive Radio Communications and Networks: Principles and Practice By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009) ALOHA and Slotted ALOHA ALOHA A station transmits a packet whenever it wants to Maximum throughput Slotted ALOHA Time is divided into slots Maximum throughput 0.368

25 Cognitive Radio Communications and Networks: Principles and Practice By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009) CSMA User senses the medium before start transmission Hold packets until the medium is free Strategies 1-persistent CSMA Non-persistent CSMA

26 Cognitive Radio Communications and Networks: Principles and Practice By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009) CSMA An example of collision in CSMA

27 Cognitive Radio Communications and Networks: Principles and Practice By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009) CSMA A typical cycle of CSMA operation

28 Cognitive Radio Communications and Networks: Principles and Practice By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009) CSMA/CA

29 Cognitive Radio Communications and Networks: Principles and Practice By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009) Hidden Terminal and Exposed Terminal Problems Hidden terminal problem Exposed terminal problem

30 Cognitive Radio Communications and Networks: Principles and Practice By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009) Routing, Energy Efficiency and Network Lifetime

31 Cognitive Radio Communications and Networks: Principles and Practice By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009) Maximizing Network Lifetime

32 Cognitive Radio Communications and Networks: Principles and Practice By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009) Congestion Control in Wireless Networks TCP is not suitable for wireless networks Basic assumption: all loss are due to buffer overflow Suffers from frequent route failures and MAC layer contention TCP enhancements Link layer mechanisms Split TCP Explicit notification schemes

33 Cognitive Radio Communications and Networks: Principles and Practice By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009) Cross-layer Design and Optimization

34 Cognitive Radio Communications and Networks: Principles and Practice By A. M. Wyglinski, M. Nekovee, Y. T. Hou (Elsevier, December 2009) Cross-layer Principles Interactions and the law of unintended consequences Dependency graph Timescale separation and stability The chaos of unbridled cross-layer design


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