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) 864-4833 FAX:(785) 864-7789 e-mail: frost@eecs.ku.edu http://www.ittc.ku.edu/ All material copyright 2006 Victor S. Frost, All Rights Reserved #1 1 Aug. 2005

Getting Connected Internet Access Medium Upstream Downstream #1 2

Getting Connected Internet Wired Local Loop #1 3

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 #1 4

Getting Connected Internet Coax Cable #1 5

Example Hybrid Fiber/Coax (HFC): Network topology Downstream Upstream Head end #1 6

Getting Connected Internet Wireless Local Loop #1 7

Example Wireless Local Loop: Physical Topology Internet #1 8 Modified from: Tanenbaum, A. Computer Networks, Prentice Hall, 4th ED 2003 #1 8

Getting Connected Internet Wireless Cell Phone #1 9

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 #1 10 Aug. 2005

Getting Connected Internet Fiber Optic Cable #1 11

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 #1 12

Getting Connected Internet Powerline #1 13

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 #1 14

Getting Connected Internet Satellite #1 15

Characteristics of Systems Data Rate Time Dynamics Bit Error rate Cost Twisted Pair Medium Low Wireless High Coax Fiber Very Low Powerline #1 16

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 #1 17

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 #1 18

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 #1 19

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 #1 20

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 #1 21

Course Reading List 1. 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. #1 22

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. #1 23