  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.
