Zero-insertion adaptive minimum mean-square error (MMSE) receiverfor asynchronous CDMA multiuser detection

摘要

This paper proposes an asynchronous code-division multiple-accessnmultiuser detector, zero-insertion adaptive minimum mean-square errorn(ZA-MMSE) multiuser detector, in which a data stream is partitioned intonblocks by inserted zero bits and detection proceeds block by block tonensure a balance between processing delay and detection efficiency. Thenbit error rate performance of the ZA-MMSE detector is evaluated underndifferent multipath scenarios with varying severity characterized bynaverage relative strength of the paths. The results are compared withndecorrelator, revealing that the ZA-MMSE detector offers promisingndetection efficiency at a relatively low complexity, which is linear tonthe product of the number of users and block length. As an effort tonimplement it adaptively, the transient behavior of the ZA-MMSE detectornwith different recursive algorithms is studied. It is concluded that thenleast mean square algorithm is not suitable due to its power-dependentnconvergence; whereas the recursive least square algorithm offers anconsistently fast convergence regardless of the received power, makingnit ideal for application in a time-varying channel with near-far effect