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Report that appeared in conference proceedings
I briefly outline the work I am doing as part of my undergraduate thesis ( final year project ), and other related projects I have been involved in.
Performance of uplink/downlink MAC techniques for 4G wireless
communications
This is the final year project ( undergraduate thesis ) that I have to complete to fulfil the credit requirements to be awarded a Bachelor's degree in Electronics and Communications Engineering.
Motivation: Present-day public wireless communications systems, such as GSM, IS-136 or CDMA, do not perform statistical multiplexing on the air-interface. This is in spite of the fact that the air-interface is the resource that contributes maximum to the cost of setting up a communications system. Spectrum licenses cost billions, both in the United States and in Europe. But spectrum efficiency is still not very high, simply because physical layer technology still has not developed to the point to allow statistical multiplexing of traffic on the air-interface to be implemented. But with the advent of OFDM, which is the physical layer that 4G systems will incorporate, rapid parallel channel measurements, which were impossible with earlier techniques, are now possible, paving the way for channel allocation on a per-burst basis. What are the issues in medium access control on a wireless link ? How do we maximise spectrum re-use in a cellular system, simultaneously increasing data rates ? Can we support QoS on the air-interface ? What about variable bit-rates ? These are some of the questions I attempt to answer in my project. In fact, I already have some of the answers.
Resources: My project guide is Dr. Srikanth, a member of the research faculty at the AU - KBC Research Centre ( www.au-kbc.org ). This is a centre for sponsored research, and has excellent computational facilities, among other things, which I utilise for my project.
My project is primarily centred around a simulation of the cellular system, where I try the various MAC techniques and compare their performance. I have not used any simulator program ( such as ns or OPNET ), but instead wrote my own code using C. My simulation runs on a Linux-based PC using the GNU gcc compiler - my bit to use non-pirated Open Source software :)
Past work / References / Related Literature: I have listed some of the journal publications / online literature that I have read during the course of working on my project.
1. I. Katzela and M. Naghshineh, Channel Assignment Schemes for Cellular Mobile Telecommunication Systems: A Comprehensive Survey, IEEE Personal Communications, pp. 10-31, vol. 3, June 1996. This article is also available on the Internet for download on the website of the IEEE Communication Surveys - click on this link.
2.Matthew Cheng and Li Fung Chang, Wireless Dynamic Channel Assignment Performance Under Packet Data Traffic, IEEE Journal on Selected Areas in Communications, pp. 1257-1269, vol. 17, no. 7, July 1999.
3.Justin C.-I. Chuang, Performance Issues and Algorithms for Dynamic Channel Assignment,IEEE Journal on Selected Areas in Communications, pp. 955-963, vol. 11, no. 6, August 1993.
4.Justin C.-I. Chuang and Nelson R. Sollenberger, Spectrum Resource Allocation for Wireless Packet Access with Application to Advanced Cellular Internet Service, IEEE Journal on Select Areas in Communications, pp. 820-829, vol. 16, no. 6, August 1998.
5.L. J. Cimini, Jr., J. C.-I. Chuang and Nelson R. Sollenberger, "Advanced Cellular Internet Service", IEEE Communications Magazine, pp. 150-159, October 1998.
6.Magnus Eriksson, Evaluation of Packet-by-Packet Downlink Radio Resource Management Schemes, published by Radio Communications System Group, Royal Institute of Technology, Sweden. Available online - click here
7.Vincent Huang and Weihua Zhuang, QoS-Oriented Access Control for 4G Mobile Multimedia CDMA Communications, IEEE Communications Magazine, March 2002.
Linux router: The Department of Electronics and Communications Engineering, Anna University, has a LAN which is connected to the campus-wide LAN, and to the Internet. A PC-based router was set up, using Linux, to act as a firewall between the rest of the campus LAN, and the departmental LAN.
Inter-campus WAN setup: Anna University has a campus at Guindy, and at Chromepet, in Madras. The LANs at the two locations are connected using a 2 Mbps WAN link. Both the LANs have their own independent leased line connection to the Internet. The requirement was to set up routing and firewall rules so as to allow transparent interconnection of the two geographically-diverse LANs, and also allow one LAN to use the other LAN's Internet connection when necessary ( eg: Chromepet campus Internet connection fails, and Chromepet users go through the Guindy campus Internet connection ). I assisted the network administrator at the Chromepet campus, and now there is seamless interconnection between the two LANs. For example, I use the setup to video-conference with my project guide, since my course lectures are at Guindy, while my project guide has his office at Chromepet.
manisridhar at hotmail dot com