Robust Analog Beamforming for Periodic Broadcast V2V Communication

TL;DR

This paper introduces robust analog beamforming techniques for periodic V2V broadcast communication, optimizing transmission parameters to minimize worst-case burst errors under challenging propagation conditions without channel knowledge.

Contribution

It analytically derives optimal parameters for analog beamforming networks and antenna switching, demonstrating their robustness and equivalence to Alamouti schemes in V2V scenarios.

Findings

Optimal parameters minimize burst error probability.

ABN and ASN perform similarly to Alamouti scheme.

Derived parameters are optimal with hybrid combining at receiver.

Abstract

We generalize an existing low-cost analog signal processing concept that takes advantage of the periodicity of vehicle-to-vehicle broadcast service to the transmitter side. In particular, we propose to process multiple antennas using either an analog beamforming network (ABN) of phase shifters, or an an antenna switching network (ASN) that periodically alternate between the available antennas, to transmit periodic messages to receivers that have an analog combining network (ACN) of phase shifters, which has been proposed in earlier work. To guarantee robustness, we aim to minimize the burst error probability for the worst receiving vehicular user, in a scenario of bad propagation condition that is modeled by a single dominant path between the communicating vehicles. In absence of any form of channel knowledge, we analytically derive the optimal parameters of both ABN and ASN. The ABN beamforming vector is found to be optimal for all users and not only for the worst receiving user. Further, we demonstrate that Alamouti scheme for the special case of two transmit antennas yields similar performance to ABN and ASN. At last, we show that the derived parameters of the two proposed transmission strategies are also optimal when hybrid ACN-maximal ratio combining is used at the receiver.