UC San Diego

Device-to-device (D2D) communication allows direct transmission between multiple transmitter-receiver pairs in cellular systems by reusing the spectrum, and offloads local traffic from the base station.

In resource allocation for a D2D video transmission system in a block fading environment, the performance improvement by applying the exact symbol error rate (SER) is compared with the conventional signal-to-interference-plus-noise-ratio (SINR) based SER evaluation method that uses a Gaussian approximation (GA) for the aggregated interference. An analytical SER expression for a D2D system using multicarrier bandlimited QAM is derived and then used in the resource allocation algorithm. Centralized resource allocation for the D2D system is considered, given knowledge of the channel state information and the rate distortion information of the video streams, and an iterative algorithm for subcarrier assignment and power allocation is proposed. Bit-level simulations for different numbers of D2D pairs demonstrate a considerable improvement on user capacity and video peak signal-to-noise ratio by incorporating the proposed SER expression compared to the GA. By invoking the conditions under which the central limit theorem holds, and comparing these conditions with the number of interferers and the power ratio of the dominant interferer in the simulated D2D system, the reason why the GA for the interference results in a pessimistic performance is also studied.

Resource allocation algorithms for D2D video transmission with a filter bank multicarrier waveform in a Rayleigh fading environment are investigated. The co-channel interference between D2D pairs is analyzed, and a cross-layer algorithm with a subcarrier assignment outer loop and a power control inner loop, which aims to optimize the overall video quality, is proposed. Unlike the non-convexity in physical layer power control for maximizing the total throughput, the cross-layer power control problem is convex under certain conditions, so a high quality solution for power control can be efficiently found. Simulation results demonstrate a higher overall video quality by the proposed cross-layer algorithm compared to baseline algorithms.