Performance of open loop transmit diversity schemes in the downlink multicell CDMA system

We present the performance comparison of delay transmit diversity (DTD), orthogonal transmit diversity (OTD) and space time spreading (STS) schemes in the downlink multicell CDMA systems. The performance was analyzed using the RAKE receiver and the decorrelating receiver under multiuser and multipath conditions. The analysis highlights the effect of multiple access interference on the performance of the system. We derive the instantaneous signal to interference and noise ratio (SINR) for all three schemes using both RAKE and decorrelating receivers. A numerical study is performed to compare the bit error rate (BER) performance of these schemes. We observe that the STS scheme outperforms the other two schemes irrespective of the type of receivers used.