Space-frequency index modulation for combating ICI in intelligent mobility communications

Advanced wireless communications to support high vehicular speeds in the scenario of intelligent mobility have attracted considerable research attentions in both academia and industry. Multi-dimensional index modulation, which exploits transmission media resources for combining the concept of index modulation to achieve higher throughput with lower energy consumption, is regarded as a potential candidate for addressing the challenges in intelligent mobility communications. However, for the multi-dimensional index modulation system used in the mobile environment, the inter-carrier-interference (ICI) imposes a significant adverse impact on the system, especially in the context of multicarrier transmission. Therefore, by focusing on the two-dimensional index modulation system, the ICI impact on space-frequency index modulation is studied in this paper. Thanks to the grouping strategies and the Gaussian approximation to model the ICI, the approximate theoretical bounds for the error performance of the two dimensional systems are derived. Moreover, a novel robust space-frequency index modulation scheme is also developed. Finally, simulation results are presented to validate the system performances and the theoretical derivations

Hierarchical Beamforming: Resource Allocation, Fairness and Flow Level Performance

We consider hierarchical beamforming in wireless networks. For a given population of flows, we propose computationally efficient algorithms for fair rate allocation including proportional fairness and max-min fairness. We next propose closed-form formulas for flow level performance, for both elastic (with either proportional fairness and max-min fairness) and streaming traffic. We further assess the performance of hierarchical beamforming using numerical experiments. Since the proposed solutions have low complexity compared to conventional beamforming, our work suggests that hierarchical beamforming is a promising candidate for the implementation of beamforming in future cellular networks.Comment: 34 page