42 research outputs found
System Energy-Efficient Hybrid Beamforming for mmWave Multi-user Systems
This paper develops energy-efficient hybrid beamforming designs for mmWave
multi-user systems where analog precoding is realized by switches and phase
shifters such that radio frequency (RF) chain to transmit antenna connections
can be switched off for energy saving. By explicitly considering the effect of
each connection on the required power for baseband and RF signal processing, we
describe the total power consumption in a sparsity form of the analog precoding
matrix. However, these sparsity terms and sparsity-modulus constraints of the
analog precoding make the system energy-efficiency maximization problem
non-convex and challenging to solve. To tackle this problem, we first transform
it into a subtractive-form weighted sum rate and power problem. A compressed
sensing-based re-weighted quadratic-form relaxation method is employed to deal
with the sparsity parts and the sparsity-modulus constraints. We then exploit
alternating minimization of the mean-squared error to solve the equivalent
problem where the digital precoding vectors and the analog precoding matrix are
updated sequentially. The energy efficiency upper bound and a heuristic
algorithm are also examined for comparison purposes. Numerical results confirm
the superior performances of the proposed algorithm over benchmark
energy-efficiency hybrid precoding algorithms and heuristic ones.Comment: submitted to TGC