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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: [email protected]
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.