Rate Loss Analysis for Multiple-Antenna NOMA with Limited Feedback

In the limited feedback downlink multiple-input single-output (MISO) non-orthogonal multiple access (NOMA) system, both the effective channel gain and the channel direction need to be quantized. The quantization error affects the feasible region of NOMA and the rate loss compared with the full channel state information (CSI) case. In this letter, we analyze this effect and obtain upper bound for the rate loss. The numerical results show that the sum rate of the limited feedback MISO-NOMA system approaches that of the full CSI as the number of feedback bits increases.