Performance evaluation of a frequency selective millimeter wave system with limited feedback

Following the recent interest in millimeter wave (mmWave) for wireless applications and the difficulty in having the channel state information at transmitter due to the large amount of data required for feedback, a low complex uniform-based limited feedback technique is proposed, for a mmWave massive MIMO OFDM-based (Orthogonal Frequency Division Multiplexing) system. The wideband mmWave system has both transmitter and receiver equipped with a large antenna array, and employs a hybrid analog-digital precoding and combiner: the digital precoder is applied in the frequency domain and differ from subcarrier to subcarrier, while the analog precoder is frequency flat. The limited feedback strategy employs a uniform-based quantization for channel amplitudes, angle of departure and angle of arrival in time domain. After being fed back, these information is used to reconstruct the overall channel in frequency domain and the transmit antenna array, which are then used to compute the hybrid analog-digital precoders. Numerical results show that the proposed quantization strategy achieves a performance close to the one obtained with perfect full channel with a low overhead and complexity.