A dual-layer differential equal gain transmission technique using M-PSK constellations

We propose a dual-layer differential codebook using M-ary phase shift keying (M-PSK) constellation as its codeword elements. Due to the temporal correlation of the adjacent channel matrices, the consecutive precoding matrices are likely to be similar. This approach quantize only the differential information of the channel instead of the whole channel subspace, which virtually increase the codebook size to realize more accurate quantization of the channel. Especially, the proposed codebook has the constant modulus property, complexity reduction, and nested property. The mobile station can be designed by using less expensive non-linear amplifier utilizing constant modulus property. Computer simulations show that the achievable throughput of the proposed dual-layer codebook performs better than LTE codebook with the same amount of feedback information.