Caching and D2D Assisted Wireless Emergency Communications Networks with Statistical QoS Provisioning

Along with natural disasters, the destruction of communication infrastructures leads to the congestion or failure of communication networks. Unmanned aerial vehicles (UAVs), which are with a high flexibility, can be employed as temporary base stations to establish emergency networks. To relieve the backhaul burden of UAVs, some imperative contents can be cached by terrestrial cache-enabled rescuers (CERs) and provide for victims with device-to-device (D2D) transmissions. To support the effectiveness and timeliness of emergency communication, the delay-bounded quality-of-service (QoS) requirement and network throughput are desired to be comprehensively considered, which imposes a new challenge for caching placement and CER deployment. In this paper, we focus on joint caching placement and CER deployment to maximize the effective capacity subject to delay-bounded QoS requirement. The overall non-convex problem is transformed into the caching placement and the CER deployment sub-problems. Then, we develop the QoS-aware caching placement scheme with fixed CER deployment density and obtain the QoS-aware CER deployment density with fixed caching placement. Based on the block-coordinate descent method, we also propose the joint caching placement and CER deployment scheme, which can not only effectively enhance average effective capacity but also guarantee the delay-bounded QoS requirement. Also, numerical simulations are con-ducted to show the performances of the proposed schemes. © 2020, Posts and Telecom Press Co Ltd. All rights reserved.