Performance of MIMO-extended UMTS-FDD downlink comparing space-time RAKE and linear equalizer

The paper discusses the performance of a MIMO-extended UMTS-FDD downlink with 2/spl times/2 and 4/spl times/4 antenna configurations. An analytical expression is derived for the average signal-to-interference ratio (SIR) of a space-time (ST) RAKE receiver in an interference dominated environment. Simulations are used to assess the BER performance with the number of concurrent users as a parameter. The results are compared to a single antenna link with equivalent data rate. In addition to that, a linear zero forcing (ZF) and an MMSE MIMO equalizer receiver are evaluated and compared to the ST-RAKE. It is shown that both methods can successfully mitigate the significant performance limitation due to self interference (SI) and multiple access interference (MAI).