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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 large-scale multiple-input multiple-output (MIMO) systems, pilot reuse among multiple cells is an important factor that affects the system reachable rate. In this paper, a generalized channel model is chosen, and the lower bound of the uplink achievable rate under the two kinds of channel estimation methods, least square (LS) and minimum mean square error (MMSE), is considered considering the system using power control. The impact of pilot reuse on the number of base stations with an infinite number of antennas is analyzed using this lower bound. The results show that under the unrelated channel, the uplink ULR is limited only by pilot pollution and the introduction of power control makes this rate partly Pilot pollution is not determined by the large-scale fading coefficient of users interfering with the base station of each cell. In the relevant channel, pilot pollution is not the only factor restricting the system’s ultimate rate. Pilot pollution always exists when LS channel estimation is used, while MMSE Pilot pollution may disappear under channel estimation.