A simple diversity technique using spread space-time block coding in MIMO systems

We propose a simple diversity technique using spread space-time block coding in multiple input multiple output (MIMO) systems. It spreads the transmission data into multiple sub-streams on different antennas by using Walsh codes. The proposed scheme does not sacrifice spectrum efficiency while maintaining a low complexity receiver. Owing to the transmission symbols of different transmit antennas passing through all the sub-channels between transmit-receive antenna pairs, the system obtains the partial additional space diversity gain of all paths. It is also shown that the diversity gain is affected by the order of receive diversity and maintains linear improvement with the increase of transmit antennas.