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Victor S. FrostDan F. Servey Distinguished Professor Electrical Engineering and Computer

ScienceUniversity of Kansas2335 Irving Hill Dr.

Lawrence, Kansas 66045Phone: (785) 864-4833 FAX:(785) 864-

7789 e-mail: frost@eecs.ku.edu

http://www.ittc.ku.edu/

How to Connect: An Introduction to Access Technologies

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All material copyright 2006Victor S. Frost, All Rights Reserved

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Getting Connected

Internet

AccessMedium

Downstream

Upstream

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Getting Connected

Internet

WiredLocal Loop

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Example

• Digital Subscriber Line: Physical topology

I nternetInternet

Telephone Lines

• NID = Network Interface Device

• DSLAM= Digital Subscriber Line Access Multiplexer

Modified from: Tanenbaum, A. Computer Networks, Prentice Hall, 4th

ED 2003

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Getting Connected

Internet

Coax Cable

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I nternetInternet

Headend

• Hybrid Fiber/Coax (HFC): Network topology

Example

DownstreamUpstream

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Getting Connected

Internet

WirelessLocal Loop

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Example

• Wireless Local Loop: Physical Topology

Internet

Modified from: Tanenbaum, A. Computer Networks, Prentice Hall, 4th

ED 2003

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Getting Connected

Internet

WirelessCell Phone

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AC = authentication center BSS = base station subsystem EIR = equipment identity register HLR = home location register

Wirelineterminal

MSC

PSTN

BSS BSS

STP SS7HLRVLR

EIRAC

MSC = mobile switching centerPSTN = public switched telephone network STP = signal transfer point VLR = visitor location register

Example

Base station• Transmits to users

on forward channels

• Receives from users on reverse channels

Mobile Switching Center

• Controls connection setup within cells & to telephone network

• Cellular Network: Physical Topology

I nternetInternet

Modified from: Leon-Garcia & Widjaja: Communication Networks

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Getting Connected

Internet

Fiber OpticCable

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Example

• OLT= Optical Line terminal

• ONT = Optical Network Terminal

• ONU=Optical network Unit

• SDU= Single Dwelling Unit

• MDU/MTU= Multiple Dwelling/Tenant Unit

I nternetInternet

Modified from: G. Keiser, FTTX Concepts and Applications, Wiley, 2006

Fiber

Fiber

FiberFiber

• Passive Optical Network (PON): Physical topology

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Getting Connected

Internet

Powerline

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Example Powerline

• M= Power Meter Unit

• Broadband Powerline Communications: Physical topology

M

Home LAN

Transformer

Base/MasterStation

InternetInternet

Power GridLow voltage power network

In-home power

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Getting Connected

Internet

Satellite

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Characteristics of Systems

Data Rate

Time Dynamics

Bit Error rate

Cost

Twisted Pair

Medium

Low Medium Medium

Wireless Medium

High High Low

Coax Medium

Low Low Low

Fiber High Low Very Low High

Powerline Low High High Medium

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Course Outline

• Review of basic networking principles• Introduction to network performance

metrics– What is ideal?– Application types– Barriers to achieving the ideal– Performance metrics– Network Performance Perspective– What performance can the network

guarantee

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Course Outline

• Techniques for coping with access (last hop) impairments– Techniques for coping with noise

• Forward error detection/correction coding• Automatic Repeat reQuest (ARQ)• Incremental Redundancy• Co-existence or modifications to end-to-end protocols:

End-to-End (TCP) vs ARQ• Case Study: TCP Performance over Multilink PPP in

Wireless Networks: Theory and Field Experiences– Techniques for coping with multipath fading

• Equalizers• Diversity• RAKE receivers• OFDM

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Course Outline

• Resource Sharing Principles and Mechanisms for Access Networks– Review general access network topologies– Resource sharing principles

• Resource reservation (call) model• Dedicated resources• Shared after reservation• Always-on model• Polling• Access

– Asymmetric mechanisms• Assumptions• General descriptions• Scheduling in the downstream• Contention in the upstream

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Course Outline

– Scheduling• What is packet scheduling?• Why is it needed?• What are the requirements for scheduling

algorithms?• Specific algorithms

– FIFO– RR– WFQ– How scheduling is used in access networks,

opportunistic scheduling, e.g., PFQ

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Course Outline

• Specific systems– DOSCIS– IEEE 802.16/Wi-Max– 3G cellular, WCDMA, HSDPA/HSUPA, EV-DO– Case Study: Mitigating scheduler induced starvation

in 3G wireless networks– EPON– Powerline

• Wireless access of the future: Cognitive Radio Communications for Dynamic Spectrum Access

• Summary of commonalities and differences

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Course Reading List1. Broadband technology overview. 2005, Corning. p. 1-16.

http://www.corning.com/docs/opticalfiber/wp6321.pdf#search=%22broadband%20technology%20overview%22

2. Balakrishnan, H., et al. A comparison of mechanisms for improving TCP performance over wireless links. in ACM Sigcomm August 1996. 1996. Stanford, CA.

3. Bianchi, G., I. Tinnirello, and G. Conigliaro, Design and performance evaluation of an hybrid reservation-polling MAC protocol for power-line communications. International Journal of Communication Systems, 2003. 16(5): p. 427-445.

4. Eklund, C., et al., IEEE standard 802.16: a technical overview of the WirelessMAN air interface for broadband wireless access. Communications Magazine, IEEE, 2002. 40(6): p. 98-107.

5. Fattah, H. and C. Leung, An overview of scheduling algorithms in wireless multimedia networks. Wireless Communications, IEEE, 2002. 9(5): p. 76-83.

6. Fellows, D. and D. Jones, DOCSIS cable modem technology. Communications Magazine, IEEE, 2001. 39(3): p. 202-209.

7. Ghosh, A., et al., Broadband wireless access with WiMax/802.16: current performance benchmarks and future potential. Communications Magazine, IEEE, 2005. 43(2): p. 129-136.

8. Gyasi-Agyei, A. and S.-L. Kim, Cross-layer multiservice opportunistic scheduling for wireless networks. IEEE Communications Magazine, 2006. 44(6): p. 50-57.

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Course Reading List

9. Haykin, S., Cognitive radio: brain-empowered wireless communications. Selected Areas in Communications, IEEE Journal on, 2005. 23(2): p. 201-220.

10.Lin, Y.-D., W.-M. Yin, and C.-Y. Huang, An Investigation into HFC MAC Protocols: Mechanisms, Implementation, and Research Issues. IEEE Communications Surveys, 2000.

11.McGarry, M.P., M. Maier, and M. Reisslein, Ethernet PONs: a survey of dynamic bandwidth allocation (DBA) algorithms. Communications Magazine, IEEE, 2004. 42(8): p. S8-15.

12.Parkvall, S., et al., Evolving 3G mobile systems: broadband and broadcast services in WCDMA. Communications Magazine, IEEE, 2006. 44(2): p. 30-36.

13.Pavlidou, N., et al., Power line communications: state of the art and future trends. Communications Magazine, IEEE, 2003. 41(4): p. 34-40.

14.Sarikaya, B., Packet mode in wireless networks: overview of transition to third generation. Communications Magazine, IEEE, 2000. 38(9): p. 164-172.

15.Tian, Y., K. Xu, and N. Ansari, TCP in wireless environments: problems and solutions. IEEE Radio Communications, 2005: p. S27-S32.

16.Zheng, J. and H.T. Mouftah, Media access control for Ethernet passive optical networks: an overview. Communications Magazine, IEEE, 2005. 43(2): p. 145-150.