Partial and Analog Feedback for MISO Precoding Systems

We consider a multiple input single output antenna system with a feedback link. While most of the previous works have considered perfect feedback channels, in this paper, we evaluate the impact of a noisy feedback channel on the quality and the performance of the transmission. We compare the finite rate feedback scheme with the analog feedback schemes where the channel parameters are transmitted without quantization over the uplink channel. Two analog feedback schemes are considered : the feedback of the channel vector and the feedback of the normalized channel vector. We provide bounds on the performance and give numerical results. We have shown that at low to medium uplink SNR the analog feedback of the normalized channel vector outperforms the analog feedback of the channel vector. Depending on the range of uplink SNR, quantized feedback can perform poorly compared to analog feedback.