We investigate the performance gains of a transmission scheme in LTE-A networks where vehicles act as relaying cooperating terminals. The advantages of vehicular relaying networks are the abundant energy and computing power, the predictable mobility patterns of vehicles, and the availability of information from positioning systems and map-based technologies. The frequent availability of traveling vehicles, operating in an ad hoc fashion, eliminates the need for establishing a dedicated relaying infrastructure. However, the associated wireless links are characterized by a doubly-selective fading channel. This causes performance degradation in terms of error probability.
Hence, we propose a precoded cooperative transmission technique to extract the underlying rich multipath-Doppler-spatial diversity. Furthermore, we implement a relay selection scheme to take advantage of the potentially large number of available relaying vehicles. We further contribute by the derivation of a closed-form error rate expression as a bench mark to assess our analysis and future research studies of such an approach. Our analytical and simulation results indicate that significant diversity gains are achievable, and that error rates can be greatly reduced. As well, there is a noticeable reduction in the required transmitting powers compared to the traditional transmission schemes.