Abstract
Multi-user detection allows for the efficient use of bandwidth in Code-Division Multiple-Access (CDMA) channels through mitigation of near-far effects and multiple-access noise limitations. Due to its inherent noise and multipath immunity, CDMA multi-access is being considered as a platform for personal communication systems (PCS). As CDMA based digital communication networks proliferate, the need to determine the presence of a new user and integrate knowledge of this new user into the detection scheme becomes more important. The decorrelating detector is a linear multi-user detector that is asymptotically optimal in terms of near far resistance; however, in the presence of a new unknown user, performance of the decorrelator is severely degraded. Adaptive decorrelators are constructed which adaptively augment an existing conventional decorrelator to demodulate a new active user in addition to existing users. Several likelihood ratio based schemes are employed. Both synchronous and asynchronous communication are investigated.
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This research was supported by the U.S. Army Research Office under Grant DAAH04-93-G-0219.
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Mitra, U., Poor, H.V. Adaptive decorrelating detectors for CDMA systems. Wireless Pers Commun 2, 265–290 (1995). https://doi.org/10.1007/BF01099636
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DOI: https://doi.org/10.1007/BF01099636