Performance of trellis-coded OFDM with antenna diversity

This paper studies the link performance of coded OFDM systems via both analysis and simulation. We first show that the level of frequency diversity that can be exploited by coding across subcarriers is not only decided by the code design, but also limited by the channel delay spread. The analysis also shows the performance improvement of multi-antenna OFDM systems over single-antenna systems. In order to maximally exploit both spatial and frequency diversity, we then propose to use the Alamouti transmit diversity scheme to first optimally exploit the spatial diversity, and then use bit interleaved coded modulation (BICM) to obtain the maximum level of frequency diversity. This design is compared with many existing space-time codes that follow a joint spatiotemporal design philosophy. Simulation results show that our design outperforms the latter under both frequency-selective and frequency-flat channels, even though the space-time codes we simulated are designed for frequency-flat channels