Traffic channel SIR estimation based on reverse pilot channel

Signal-to-interference ratio (SIR) is a very important metric of communication link quality. For wireless cellular systems, several control mechanism, such as power control, rate control, and allocation of radio resource are based on SIR estimation. In previous research, most of researches concentrate on WCDMA system in which pilot symbol is time-multiplexed with data symbol, this method is not feasible for cdma2000 system where pilot symbol is code-multiplexed with data symbol. This paper first develops SIR estimators based on reverse pilot channel and then derives the approximate analytic expression for its mean squared error (MSE) function, the accuracy of which is validated through simulation. It is shown that the MSE of the new SIR estimator is significantly smaller than the MSE of other widely used SIR estimators, especially in low SIR case.