Amplitude and phase estimation considerations for asynchronous CDMA with successive interference cancellation

Successive interference cancellation, in conjunction with very low rate convolutional codes, has been shown to approach the Shannon capacity of a Gaussian channel. This approach to CDMA is very well suited to asynchronous (uplink) wireless channels. However, accurate phase and amplitude estimation is required for effective operation. In this paper, we develop a power control algorithm specifically designed to relax the requirements on estimation accuracy. Using this power control algorithm in conjunction with superorthogonal codes and successive interference cancellation, it is shown that even with average estimation error up to 30%, the capacity over an IS-95 CDMA system can be increased by an order of magnitude