بازیابی اطلاعات تعاونی کدگذاری شبکه در شبکه های تلفن همراه 802.11/ سلولی

By utilizing free WiFi transmissions, network coded cooperative peer-to-peer (P2P) information repair (NC-CPR) has been proposed to mitigate packet loss incurred during cellular Base Station (BS) broadcast. However, most of the work focuses on static network environment. While considering peer movement, the challenge part is the dynamically changed network topology, making it hard to control the transmission collisions to achieve good repair performance. In this paper, we propose the network coded cooperative information repair protocol with mobility concern (NC-CIRM) to recover the lost packets under the mobile scenario. Peer transmissions are scheduled with different channel access priorities based on their neighborhood information. Then, the NC-CIRM with known distribution (NC-CIRMD) protocol is presented which obtains neighborhood information based on the knowledge of node spatial distributions. Simulation results show that these two protocols achieve similar repair performance and work efficiently under both uniform and stationary node spatial distributions. Furthermore, a tunable parameter – coded packet generating rate based repair protocol (TP-RP) is proposed to further improve repair performance when the peers uniformly distribute within the system area. At the mean time, an analytical model is developed, then based on which parameter optimization is studied and theoretical results are derived. Extensive simulation results illustrate the improvement made by TP-RP protocol compared with the other two protocols and validate the accuracy of the optimal value of the tunable parameter.