Low Complexity Channel Estimation for mmWave Hybrid MIMO Systems

Mm Wave communication is a key enabling technology for achieving high data rate required in the next generation mobile networks. Hybrid MIMO architectures are proposed to exploit antenna array gain in spite of reasonable power consumption and low complexity in the mm Wave frequencies. Channel estimation techniques for Hybrid MIMO systems are mainly based on formulating the channel estimation as a sparse signal reconstruction problem due to the sparsity in angular domain. we proposed a method to reduce the complexity of orthogonal matching pursuit (OMP) algorithm for sparse signal recovery. Our proposed method benefits from a recursive manner instead of matrix inversion and Also, we avoid repetitive similar inner products by storing pre-calculated gram matrix of sampling matrix and use desired elements when needed. Accordingly, we can significantly reduce the complexity of channel estimation especially for higher number of measurements.