Non-terrestrial networks (NTN) can provide connectivity in unreachable or remote areas. The massive multiple-input multiple-output (MIMO) is a promising architecture for future NTN networks through different platforms, such as earth orbit satellites or airborne vehicles. The long transmission distance and large coverage area challenge the physical layer design in a massive MIMO system. In particular, there is a clear trade-off between power amplifier (PA) efficiency and linearity: PAs are most efficient close to saturation, generating the most nonlinearities and degrading the achievable rate. In this paper, we study the power allocation and array selection in a distributed LoS massive MIMO system with maximum ratio transmission (MRT), by taking PA nonlinearity characteristics into account. With the objective to maximize the sum spectral efficiency (SE) with total power constraints, we first formulate the power allocation problem as nonlinear programming. Then, we propose an iterative power allocation algorithm based on the multiplier punitive method. Simulation results corroborate that the proposed power allocation can maximize spectral efficiency with awareness of the PA nonlinearity and significantly prevents it from degrading performance.
Power Allocation for Distributed Massive LoS MIMO with Nonlinear Power Amplifiers
2022-09-01
275894 byte
Conference paper
Electronic Resource
English