IEEE802.11n物理层性能评估.pdf

ieee communications surveys revised 26 august 2009 t paul is pursuing his ph d at santa clara university santa clara ca 95053 usa e mail tpaul scu edu t ogunfunmi is with the electrical engineering department santa clara university santa clara ca 95053 usa e mail togunfunmi scu edu digital object identifi er 10 1109 surv 2009 090408 multiple output are used to achieve these rates these mimo techniques include spatial division multiplexing sdm trans mitter beamforming and space time block coding in electri cal engingeering stbc used either to increase throughput over single antenna systems by two to four times or to improve range of reception depending on the environment in our discussion here the focus is on the phy layer design and thus minimal treatment of the media access control mac layer is given this paper evaluates the architectural differences of the phy layers in the tgn joint tgn sync and wwise proposals references 1 2 and 3 respectively for the ieee 802 11n standard and provides key insights into the choices made after a brief history of the development of the 11n amendment the approaches for channel estimation bit interleaving space time block coding and pilot tone usage are analyzed in an effort to characterize the performance benefi ts of each proposed technique simulation models developed in matlab simulink are used for performance verifi cation extensive work has been done by numerous researchers based on the phy layer designs discussed in this paper some examples of their research as well as surveys and comparisons with other technologies can be found in references 23 to 31 which cover topics such as mimo receiver design 23 low density parity check ldpc coding 25 transmit beamforming 27 and antenna selection method 28 a study of the evolution of the ieee 802 11 standard in terms of its history the channel model and current transceiver design for the 11n standard is given by the authors in 13 however this paper differs in that the focus is on providing an in depth comparative analysis of the three main proposals for the 11n standard the tgn sync wwise and tgn joint proposals the goal of this paper is not only to educate its readers on the evolution of the 11n amendment but also to provide insights into the design choices made for the current 11n proposal these insights are provided in terms of the lessons learned from the presented analysis of the competing proposals initially put forth for the amendment we begin with a history of the evolution of the 11n amend ment in section ii section iii contains a description of the main proposals for the standard section iv gives background on the key signal processing techniques used for the 11n standard in section v the areas of channel estimation bit interleaving space time block coding and pilot tone selection are considered individually as well as in combination in an effort to characterize the performance of each proposed technique for the next generation wlan standard insights are offered into the choices made in each area in an effort to 1553 877x 09 25 00 c 2009 ieee authorized licensed use limited to chongqing univ of post and telecom downloaded on march 15 2010 at 03 26 16 edt from ieee xplore restrictions apply 132ieee communications surveys http www ieee802 org 11 docfiles 03 11 03 0940 04 000n tgn channel models doc 22 y xiao ieee 802 11n enhancements for higher throughput in wire less lans ieee trans wireless commun dec 2005 23 j lee et al effi cient mimo receiving technique in ieee 802 11n system for enhanced services ieee trans consum electron vol 53 no 2 pp 344 349 may 2007 24 z cai et al effi cient encoding of ieee 802 11n ldpc codes ieee electron lett vol 42 no 25 pp 1471 1472 dec 2006 25 a behzad et al a fully integrated mimo multiband direct conversion cmos transceiver for wlan applications 802 11n ieee j solid state circuits vol 42 no 12 pp 2795 2808 dec 2007 26 j m perez et al low cost encoding of ieee 802 11n ieee electron lett vol 44 no 4 pp 307 308 feb 2008 27 p p xia et al diversity analysis of transmit beamforming and its application in ieee 802 11n systems to be published 28 q t tran et al proposal of receive antenna selection methods for mimo ofdm system ieice trans commun vol e91b no 2 pp 505 517 feb 2008 29 d niyato et al radio resource management in mimo ofdm based wireless infrastructure mesh networks issues and approaches ieee commun mag vol 45 no 11 pp 100 107 nov 2007 30 m s kuran and t tugcu a survey on emerging broadband wireless access technologies computer networks vol 51 no 11 pp 3013 3046 aug 2007 31 r van nee et al the 802 11n mimo ofdm standard for wireless lan and beyond wireless pers commun vol 37 no 3 4 pp 445 453 may 2006 thomas k paul m 06 has worked in the com munications industry since 1996 most recently he worked at intel corp on wimax product devel opment as well as the analysis of ieee 802 16m symbol structure design he also worked at atheros communications on wi fi phone product develop ment prior to that at ralink technology he worked on the development of a cost reduced version of the 802 11b wlan chipset earlier at pc tel inc he worked on the maintenance and improvement of their v 92 software modem product attaining the position of project lead product enhancement he also holds a u s patent regarding dynamic block processing in software modems he earned his b a sc degree at the university of toronto canada in 1996 and his m s e e at santa clara university santa clara california in 2007 he is currently pursuing a ph d e e at santa clara university his research interests are in communications system design adaptive and digital signal processing tokunbo ogunfunmi m 88 sm 00 is an asso ciate professor of electrical engineering and direc tor of the signal processing research lab sprl at santa clara university scu santa clara califor nia from june november 2003 he served as acting chair electrical engineering dept santa clara university at scu he teaches a variety of courses in signal processing and related areas his research interests include adaptive and nonlinear signal pro cessing artifi cial neural networks signal processing for communications applications multimedia and vlsi design he has published two books and over 100 refereed journal and conference papers in these areas dr ogunfunmi has been a consultant to industry and government and was a visiting professor at the university of texas and at stanford university his industrial experiences include consulting for companies such as broadcom amd case technology claris corp clairvoyant nec at t bell labs and nikon precision research development he is a senior member of the institution of electrical and electronic engineers i