Joint IWMMSE-based Channel Estimation and Finsler-Manifold-based Codebook for the Design of V2X FDD Massive MIMO Systems

With the rapid development of V2X communications, how to guarantee per-vehicle rate and robustness of V2X communications has become important issue for the intelligent transportation systems. When there is distortion in CSI exchange under a real (e.g., noisy) environment, the performance of the precoder feedback method will seriously degrade due to transmission latency and quantization error. In this work, we propose Finsler manifolds codebook feedback scheme for V2X massive MIMO systems, where the vehicles exchange their CSI information via V2V communications, estimate the direction from a propagating wave in the precoder of antenna transceivers, and transmit their CSIs back to the Roadside Unit (RSU). That is, with the minimizing the iterative weighted minimum mean squared estimation (IWMMSE) of the received signals, we could cope with the optimization problem of the precoder feedback scheme on Finsler manifolds for maximizing the received signal power. Moreover, we are able to properly manage the optimal precoder bit allocation in mmWave massive MIMO systems. Simulation results show that, with the IWMMSE-based estimation, our Finsler manifolds codebook feedback scheme outperforms existing approaches in terms of per vehicle rate as well as the interference mitigation, i.e., our massive MIMO system could obtain higher adaptability and stability for V2X communications.