Zero-Forcing Based Limited Feedback Hybrid Precoding in mmWave Communications

By exploiting angular sparsity that mmWave channels exhibit, limited feedback hybrid precoding (LFHP) can achieve high performance with a largely reduced system overhead. Most existing works focus on optimizing the system mutual information (SMI), where the receiver complexity is often neglected. More importantly, these SMI-oriented schemes provide no guarantee on the bit error rate (BER) performance, which is a key factor in evaluating system performance. In this paper, we work on devising a BER-oriented LFHP scheme with hybrid structure employed at the receiver. Based on the minimum BER criterion, an optimal zero-forcing based LFHP scheme is first derived when the transmitter has a digital structure. Next, an iterative algorithm is proposed to jointly construct the hybrid analog/digital precoder when both the transceivers employ hybrid structures. Simulations show that with our proposed LFHP scheme, the achieved BER under hybrid transceivers can be very close to the ideal benchmark obtained under one hybrid end.