1. An Introduction to Access Technologies
How to Connect:
An Introduction to Access Technologies #1
Victor S. Frost
Dan F. Servey Distinguished Professor
Electrical Engineering and Computer Science
University of Kansas
2335 Irving Hill Dr.
Lawrence, Kansas 66045
Phone: (785) FAX:(785)
All material copyright 2006
Victor S. Frost, All Rights Reserved
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Aug. 2005

2. Getting Connected
Internet
Access
Medium
Upstream
Downstream
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3. Getting Connected
Internet
Wired
Local Loop
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4. Example Digital Subscriber Line: Physical topology
NID = Network Interface Device
DSLAM= Digital Subscriber Line Access Multiplexer
Telephone Lines
Modified from: Tanenbaum, A. Computer Networks, Prentice Hall, 4th ED 2003
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5. Getting Connected
Internet
Coax Cable
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6. Example Hybrid Fiber/Coax (HFC): Network topology Downstream Upstream
Head
end
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7. Getting Connected
Internet
Wireless
Local Loop
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8. Example Wireless Local Loop: Physical Topology Internet #1 8
Modified from: Tanenbaum, A. Computer Networks, Prentice Hall, 4th ED 2003
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9. Getting Connected
Internet
Wireless
Cell Phone
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10. Modified from: Leon-Garcia & Widjaja: Communication Networks
Example
Cellular Network: Physical Topology
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
AC = authentication center
BSS = base station subsystem
EIR = equipment identity register
HLR = home location register
Wireline
terminal
MSC
PSTN
BSS
STP
SS7
HLR
VLR
EIR AC
MSC = mobile switching center
PSTN = public switched telephone network
STP = signal transfer point
VLR = visitor location register
Modified from: Leon-Garcia & Widjaja: Communication Networks
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Aug. 2005

11. Getting Connected
Internet
Fiber Optic
Cable
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12. Modified from: G. Keiser, FTTX Concepts and Applications, Wiley, 2006
Example
Passive Optical Network (PON): Physical topology
Fiber
OLT= Optical Line terminal
ONT = Optical Network Terminal
ONU=Optical network Unit
SDU= Single Dwelling Unit
MDU/MTU= Multiple Dwelling/Tenant Unit
Fiber
Fiber
Fiber
Modified from: G. Keiser, FTTX Concepts and Applications, Wiley, 2006
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13. Getting Connected
Internet
Powerline
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14. Low voltage power network
Example Powerline
Broadband Powerline Communications: Physical topology
M= Power Meter Unit M
Home LAN
Transformer
Base/Master
Station
Internet
Power Grid
Low voltage power network
In-home power
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15. Getting Connected
Internet
Satellite
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16. Characteristics of Systems
Data
Rate
Time Dynamics
Bit Error
rate
Cost
Twisted Pair
Medium
Low
Wireless
High
Coax
Fiber
Very Low
Powerline
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17. 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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18. 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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19. 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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20. 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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21. Course Outline Specific systems
DOSCIS
IEEE /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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22. Course Reading List
1. Broadband technology overview. 2005, Corning. p
2. Balakrishnan, H., et al. A comparison of mechanisms for improving TCP performance over wireless links. in ACM Sigcomm August 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, (5): p
4. Eklund, C., et al., IEEE standard : a technical overview of the WirelessMAN air interface for broadband wireless access. Communications Magazine, IEEE, (6): p
5. Fattah, H. and C. Leung, An overview of scheduling algorithms in wireless multimedia networks. Wireless Communications, IEEE, (5): p
6. Fellows, D. and D. Jones, DOCSIS cable modem technology. Communications Magazine, IEEE, (3): p
7. Ghosh, A., et al., Broadband wireless access with WiMax/802.16: current performance benchmarks and future potential. Communications Magazine, IEEE, (2): p
8. Gyasi-Agyei, A. and S.-L. Kim, Cross-layer multiservice opportunistic scheduling for wireless networks. IEEE Communications Magazine, (6): p
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23. Course Reading List
9. Haykin, S., Cognitive radio: brain-empowered wireless communications. Selected Areas in Communications, IEEE Journal on, (2): p
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, (8): p. S8-15.
12. Parkvall, S., et al., Evolving 3G mobile systems: broadband and broadcast services in WCDMA. Communications Magazine, IEEE, (2): p
13. Pavlidou, N., et al., Power line communications: state of the art and future trends. Communications Magazine, IEEE, (4): p
14. Sarikaya, B., Packet mode in wireless networks: overview of transition to third generation. Communications Magazine, IEEE, (9): p
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, (2): p
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