Competitive analysis of online throughput maximization schemes for multiple access channels with a shared renewable energy source

In this paper, we investigate the resource allocation schemes in a two-user Gaussian multiple access channel (MAC) with conferencing links and a shared energy harvesting (EH) source to maximize the weighted throughput for the two transmitters over a finite horizon of N time slots. In particular, we adopt a block-based EH model, for which the energy arrive at the beginning of each slot and the amount of the harvested energy is assumed to be causally known at the transmitters. We aim at measuring the utility by competitive analysis of one online passive scheme, which is proposed based on the structural properties of the optimal offline one we derived in [1]. First, we derive the upper-bound of the throughput obtained by the optimal offline scheme and the lower-bound of that obtained by this online scheme. Then, for different weighting factors, we derive the competitive ratios of the online passive scheme, i.e., the worst-case ratios between the throughputs obtained by the online and the offline schemes.