Hybrid precoding and combining algorithm for reduced complexity and power consumption architectures in mmWave communications

Future ultrahigh-speed wireless communication systems face difficult challenges due to the fundamental limitations of current technologies working at microwave frequencies. Millimeter-wave (mmWave) technologies can offer large underutilized bandwidths and ease the implementation of large antenna arrays which are required to help overcome the severe signal attenuation that occurs at these frequencies. The high cost and power consumption of a fully digital mmWave precoder and combiner can be reduced by the adoption of hybrid analog/digital designs based on analog phase shifters. The implementation can be simplified even further if each transceiver is connected to an independent antenna subarray and if the phase shifters are replaced by switches, with the possible aid of inverters. In this paper we present an hybrid design algorithm for orthogonal frequency division multiplexing (OFDM) based mmWave MIMO systems, which can cope with different analog architectures that can be adopted at either the RF precoder or combiner, in order to achieve reduced complexity and power consumption. Numerical results show that using the proposed algorithm, all the architectures can achieve good trade-offs between spectral efficiency and simplified implementation.