UCSC Broadband Communications (UCBC) Research Group

Space-time Code for Wireless MIMO Systems

MIMO technology has provided a unique opportunity to obtain high data rates in wireless communication systems. Space-time codes are powerful tools to achieve reliable communications with high data rates in MIMO systems. However, in most practical wireless systems, the mobile users have a single antenna while the base station has a large number of antennas. Cooperation diversity is a technique that attempts to address this problem in the uplink of wireless systems. We have recently introduced a new technique that can achieve coding gains of space-time convolutional codes with only a single transmit antenna when there are multiple receive antennas available. This is achieved by some signal processing at the transmitter and takes advantage of the receiver diversity. This technique can be applied to MIMO systems to design powerful space-time convolutional codes with arbitrary constellation size using QPSK space-time convolutiona code as component codes. The preliminary results suggest a significant research opportunity for MIMO systems in mobile networks and for both space-time convolutional and block codes. Next figure compares the simulation results using space-time convolutional codes for 2xm systems with spectral efficiency of 4 bits/s/Hz. The new scheme allows modular construction of space-time convolutional codes with any spectral efficiency

More information can be found in the submitted conference and Journal papers.

Simulation results are for quasi-static Rayleigh fading channel and for block length of 260 bits. We compare our proposed algorithm (PA) with space-time convolutional code of Tarokh with 16-QAM constellation size.