Cooperative spatial multiplexing with distributed amplify-and-forward relays

We propose a MIMO spatial multiplexing system with distributed single-antenna relay stations which operate in the amplify-and-forward mode. A maximum likelihood detector is implemented at the receiver. We evaluate the system bit error rate (BER) performance by means of a semi-analytic bounding method which can closely bound BER at high signal to noise ratio (SNR), and hence determine diversity order. We consider the effect of fading on links between the source and relays on the achievable diversity order.