Optimal weights for MMSE space-time equalizer of multicode CDMA system

摘要

Aspects of the invention provide an enhanced chip-level linear space-time equalizer 118 for multiple-input-multiple-output (MIMO) multi-code CDMA systems reusing same spreading codes in different transmit antennas 114. Reuse of the spreading codes at the transmitter 104, 204 creates an on-time inter-stream interference component (or cross-talk among distinct transmit antenna signals) which reuse the same spreading code as the desired signal in the soft metric sequence of the MIMO CDMA receiver after MMSE space-time equalization. The equalizer 118 has a MMSE weighting vector that takes the despreading effect into account.

主权项

1. A method comprising:
receiving a plurality of signals via a plurality of receive antennas, wherein the received signal from each receive antenna comprises a combination of one or more signals transmitted from a transmitter unit, wherein receiving a plurality of signals comprises receiving the plurality of signals via the plurality of receive antennas, wherein the received signal from each receive antenna comprises the combination of one or more signals transmitted from a plurality of transmit antennas; and processing the signal with a weighting vector having coefficients to generate a plurality of bit streams, wherein the coefficients are at least in part a function of spreading factor and are obtained by accounting for spreading code reuse by a transmitter, wherein processing the signal comprises processing the signal with the weighting vector having coefficients to generate a plurality of groups of equalized metric sequences corresponding to the plurality of transmit antennas.