In the last decades, MIMO systems were exploited to offer spatial diversity and precoders were designed for a closed-loop solution with the channel state information at the transmitter through a feedback link. Some well-known solutions optimize the capacity, the mean square error, the signal to noise ratio or the minimum distance. Nowadays, it exists a lot of different precoders with pros and cons and to obtain the most energy-efficient solution, the main concern of our research are the performance evaluation and the decrease of the complexity thanks to approaches based on the minimum distance (dmin) and its probability density function (pdf).
Hereafter are some of the research paths we are following:
- Obtain the pdf of dmin for any precoder: modulation size, number of substreams, even a cooperative scheme (lien vers la page) with synchronization error
- Consider several channel statistics (Rayleigh, Rice, correlation), ie BAN, indoor, or outdoor context.
- Propose new quantization methods of the feedback link in order to adapt the method from the open-loop to the full CSI and associated architecture solutions for precoders.
- Propose new estimates of the bit error rate and extend it to channel coding with soft or iterative decision.