大规模MIMO系统中多小区导频重用对上行可达速率的影响  

Impact of multi-cell pilot reuse on the achievable uplink rate for massive MIMO systems

作　　者：何强[1] 张秀军[1] 肖立民[1] 周世东[1] 

机构地区：[1]清华大学电子工程系清华信息科学与技术国家实验室,北京100084

出　　处：《清华大学学报（自然科学版）》2015年第5期526-531,共6页Journal of Tsinghua University(Science and Technology)

基　　金：国家科技重大专项项目(2014ZX03001014-002);国家"九七三"重点基础研究项目(2012CB316002);国家"八六三"高技术项目(2015AA01A701);国家自然科学基金资助项目(61201192);国家自然科学基金创新研究群体项目(61321061);清华-高通联合研究项目(20093000417);是德科技项目(20133000295)

摘　　要：在大规模多入多出(MIMO)系统中,导频在多小区间重用是影响系统可达速率的一个重要因素。该文选取一般化的信道模型,考虑系统采用功率控制,导出了最小二乘(LS)和最小均方误差(MMSE)这2种信道估计方法下上行可达速率的下界。利用该下界对基站天线数无穷多时导频重用的影响进行分析,结果表明:在非相关信道下,用户上行极限可达速率仅仅受限于导频污染,且功率控制的引入使得该速率部分地由导频干扰用户到各自小区基站的大尺度衰落系数决定;在相关信道下,导频污染不是制约系统极限可达速率的唯一因素,在使用LS信道估计时导频污染会始终存在,而MMSE信道估计下导频污染可能会消失。In massive multiple-input multiple-output（MIMO）systems,multi-cell pilot reuse is an important factor affecting the achievable system uplink rate.A generalized channel model with adaptable power control was used to derive the lower bound on the achievable uplink rate for both least square（LS）and minimum mean square error（MMSE）channel estimations.Then,the impact of pilot reuse as the number of base station（BS）antennas tends to infinity is analyzed based on these bounds. For uncorrelated channels,the ultimate achievable uplink rate of a user is mainly limited by pilot contamination and partially by the large-scale fading coefficients from a pilot interfering with users communicating to their base stations of their own cells due to power control.For correlated channels,pilot contamination is not the only factor that constrains the ultimate achievable system uplink rate,but always exists when LS channel estimation is used,but may vanish when MMSE is used.

关 键 词：大规模多入多出(MIMO) 导频污染 功率控制 相关信道 

分 类 号：TN929.5[电子电信—通信与信息系统]