Robust Power Control in D2D-Enabled Vehicular Communication Network

The power control scheme is investigated for device-to-device-enabled vehicular communications (D2D-V) system in this paper. The D2D-V system is underlaid in cellular network, where one cellular uplink and multiple D2D-V links share a common channel. To pursue a fine D2D-V system, the sum rate of all D2D-V links is maximized, and the cochannel cellular link reliability is ensured by the cellular user (CU) interference constraint. However, the channel is time-varying and with high uncertainty, especially in the high mobility vehicular environment. To make the power control scheme be more robust against the channel fluctuations, the CU interference probability constraint is introduced, and it is transformed into deterministic one by Bernstein approximation since the probabilistic constraint is intractable. The deterministic constraint is reformulated as a separable structure for a more efficient solution. Besides, the nonconvex problem whose objective function involves the nonconvex logarithmic form, is transformed into a convex one by successive convex approximation method. After that, a distributed robust power control algorithm is proposed to achieve the optimal solution. Numerical simulations are performed to evaluate the performance of the proposed scheme and demonstrate velocity impacts on system performance when a high mobility vehicular environment is considered.