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A Performance Analysis of the 802.11 Wireless Lan Medium Access Control

2003; Volume: 3; Issue: 4 Linguagem: Inglês

10.4310/cis.2003.v3.n4.a4

2163-4548

Nitin Gupta, P. R. Kuman,

Advanced Wireless Network Optimization

We study the performance of the IEEE 802.11 protocol.We present an extension of a methodology for the collocated one-hop case which allows the incorporation of channel errors.The results closely agree with simulation results.A delay analysis is also presented.We also present an extension of this methodology to the multi-hop case with non-collocated nodes.The approach uses specific topology dependent relations.Specific results are presented for the ring and mesh topologies, and compared against simulation results.1. Introduction.Wireless networking technologies are increasingly becoming widespread.Various wireless communication standards have evolved which try to provide protocols and standards for medium access control in the shared wireless medium.The IEEE 802.11 protocol[3], Bluetooth[7], HomeRF[9] (now disbanded) and the HiperLAN[8] are examples of such standards.The IEEE 802.11 protocol is the most widely used.The IEEE 802.11 standard defines two layers.The first layer is the Physical layer (PHY), which specifies the modulation scheme used and signaling characteristics for the transmission through radio frequencies.The second layer is the media access control (MAC) layer.This layer determines how the medium is used.This chapter provides an overview of the medium access control mechanism, specifically the Distributed Coordination function, DCF, in the IEEE 802.11 protocol.The description is followed by performance analysis of DCF for both single hop and multi-hop wireless networks.Bianchi in [1] has analyzed IEEE 802.11DCF for the single hop or the collocated case.The goodput analysis for the collocated case presented in Section 3.1, extends Bianchi's work by taking into account wireless channel errors and retry counts.A new delay analysis for the collocated case is also presented.Analyzing 802.11 protocol in multi-hop scenarios poses many new challenges.Section 3.2 presents a methodology for performance analysis of 802.11DCF in multi-hop networks.The application of the methodology to a ring topology is also presented.The numerical results show good agreement with ns-2 simulation