Comparison of SIR-based closed loop TPC in W-CDMA considering closed loop transmit diversity mode 1

This paper compares signal-to-interference power ratio (SIR) measurement techniques for SIR-based closed loop transmit power control (CL-TPC) assuming closed loop transmit diversity (CL-TD) mode 1 in forward link of wideband code division multiple access (W-CDMA) FDD mode. Traditionally, SIR measurement is performed by exploiting dedicated pilot symbols. This method, however, has inherent measurement error in it since the data symbols are coherently combined (assuming ideal feedback channel) while the dedicated pilot symbols are not. We show that SIR measurement exploiting data symbols is capable of improving the average bit error rate (BER) performance. This improvement can be achieved with relatively little effort which is attractive from implementation perspective.