A simplified cooperative spatial multiplexing scheme of MIMO-CDMA networks

The existing cooperative spatial multiplexing (CSM) schemes for MIMO-CDMA network have four vital problems to hinder CSM's application: exact synchronization among the mobile stations(MSs) and base station (BS), spatial channels' estimation for MSs, space-time coding and decoding for BS and MSs, the implementation complexity of BS and MSs. To solve the problems, a simplified cooperative spatial multiplexing scheme is proposed, including BS and MS systems, where MIMO BS in a cell has two antennas and each MS of lower moving speed has one antenna only. To ensure communication quality of the network, the scheme applies LDPC as the channel coding instead of space-time coding for BSs and MSs. BS assigns the same CDMA channels for MSs to have larger space interval. Simulations show that good spatial multiplexing capacity and BER performance have been achieved by the proposed scheme.