دانلود رایگان مقاله بازی دو مرحله ای رویکرد نظری برای کاهش تداخل با شبکه بدن به بدن

Abstract

In this paper, we identify and exploit opportunities for cooperation between a group of mobile Wireless Body Area Networks (WBANs), forming a Body-to-Body Network (BBN), through inter-body interference detection and subsequent mitigation. Thus, we consider a dynamic system composed of several BBNs and we analyze the joint mutual and cross-technology interference problem due to the utilization of a limited number of channels by different transmission technologies (i.e., ZigBee and WiFi) sharing the same radio spectrum. To this end, we propose a game theoretical approach to address the problem of Socially-aware Interference Mitigation (SIM) in BBNs, where WBANs are “social” and interact with each other. Our approach considers a two-stage channel allocation scheme: a BBN-stage for inter-WBANs’ communications and a WBAN-stage for intra-WBAN communications. We demonstrate that the proposed BBN-stage and WBAN-stage games admit exact potential functions, and we develop a Best-Response (BR-SIM) algorithm that converges to Nash Equilibrium points. A second algorithm, named Sub-Optimal Randomized Trials (SORT-SIM), is then proposed and compared to BR-SIM in terms of efficiency and computation time. series We further compare the BR-SIM and SORT-SIM algorithms to two power control algorithms in terms of signal-to-interference ratio and aggregate interference, and show that they outperform the power control schemes in several cases. Numerical results, obtained in several realistic mobile scenarios, show that the proposed schemes are indeed efficient in optimizing the channel allocation in medium-to-large-scale BBNs.

8. Conclusion

In this paper we studied the distributed interference mitigation problem in BBN scenarios from a game theoret- ical perspective. In particular, our work made three main contributions. First, we formulated the problem as a game considering the SIR, which accurately models the chan- nel capacity that can be achieved in the presence of mu- tual and cross-technology interference. Second, we stud- ied the properties of our game proving the existence of a Nash Equilibrium, which represents channel allocations that minimize the mutual and cross-technology interfer- ence. Third, we proposed a two-stage algorithm (called BR-SIM) based on the best-response dynamics to com- pute the Nash Equilibria in a distributed fashion. We fur- ther developed an alternative approach (SORT-SIM) that reaches a sub-optimal solution in less computational time than BR-SIM. Finally, we evaluated and compared our SIM game theoretical approaches to (relay-assisted) power con- trol schemes (i.e., PAPU and RSPC) in realistic BBN scenar- ios. We first showed that the BR-SIM algorithm converges quickly and achieves feasible values for the utility func- tions, while SORT-SIM presents some practicability benefits under specific network scenarios. Then, we demonstrated that BR-SIM and SORT-SIM outperform PAPU and RSPC in terms of SIR and Aggregate Interference in several cases, and especially when the network density is quite low. Besides, numerical results we gathered in the present work show that BBN scenarios require the definition of distributed scheduling algorithms to avoid simultane- ous transmissions that might affect the channel quality and completely prevent communications among network nodes.