Chapter 3
Channel Coding Assisted STBC-OFDM Systems
3.1 Introduction
Increasing market expectations for 3G mobile radio systems show a great demand for a wider range of services spanning from voice to high-rate data services required for supporting mobile multimedia communications. This leads to higher technical specifications for existing and future communication systems, which have to support data rates as high as 144 kbps in vehicular, 384 kbps in outdoor-to-indoor and 2 Mbps in indoor and picocelluar environments [410].
The employment of multiple antennas constitutes an effective way of achieving an increased capacity. The classic approach is to use multiple-receiver antennas and exploit Maximum Ratio Combining (MRC) of the received signals for the sake of improving the system’s performance [411, 412]. However, the performance improvement of MRC is achieved at the cost of increasing the complexity of the Mobile Stations (MSs). Alternatively, MRC may be employed at the Base Stations (BSs), which support numerous MSs. While this scheme provides diversity gain for the BSs’ receivers, the MSs cannot benefit from it.
Employing multiple transmitters rather than receiver antennas at the BSs constitutes a further design option in this context. Since transmitter diversity techniques are proposed for employment at the BSs, it is possible to enhance the system’s integrity by upgrading the BSs. Alamouti [400] introduced an attractive scheme, which uses two transmitters in conjunction ...
