Sub-symbol parallel interference canceling

Abstract

In an asynchronous CDMA communication system using long codes, multiple access interference can be reduced. In one aspect, Parallel Interference Cancellation (PIC) performs decoupled estimation, preferably non-linear and applied to chip spacing. According to another aspect, interference is canceled using a technique that estimates bits in a symbol by interpolating a user's signature waveform into a common sampling grid of received data. According to another aspect, multi-stage, hybrid multi-stage and reconfigurable recursive multi-stage multi-user detection structures and corresponding processing may be provided.

Description

[0001] Cross References to Related Applications [0002] This application claims benefit pursuant to 35USC 119(e) of Provisional Application 60 / 443,655, filed January 30, 2003, entitled "Multi-User Detection Techniques for CDMA." technical field [0003] The present invention relates generally to communications, and more particularly to improving communication system performance by canceling interference, and more particularly to improving cancellation of multiple access interference in code division multiple access communication environments. Background technique [0004] Code Division Multiple Access ("CDMA") provides an efficient communication technique for sharing a communication channel among several users. Unfortunately, when the channel is overcrowded, conventional CDMA receivers work poorly and multiple access interference (MAI) severely degrades performance. Although a maximum likelihood receiver is easy to describe in this context, it is nearly impossible to imple...

AI Technical Summary

Problems solved by technology

[0009] Each of the conventional techniques was found to be either too complex to be implemented in practical applications, or insufficient for practical use with respect to practical MAI cancellation

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