On Hit Rate Improving and Energy Consumption Minimizing in Cache-Based Convergent Overlay Network on High-speed Train

Abstract

Content caching and energy consumption to protract user device lifetime while bolstering the hit rate when mobility is beyond 300Kmph is challenging. In this paper, we consider a cache-based convergent overlay network comprising cellular base stations and terrestrial broadcast networks as effective means to deliver the services in high-speed train(HST). Most popular contents with high Zipf rank are pushed and cached using broadcast network in user devices and relay system on HST to offload the network traffic and bring user experience upfront leveraging energy. Presence of cache in relay system (RS), users can get the services without delay. However, if user's request for contents are served by cellular network from cloud, they face throughput bottleneck with delay and increased transmission time. This eventually leads increase in user device energy consumption. A popular contents caching scheme with constraints of location, limited storage size and limited power of user device is modeled as closed form expression to maximize users local hit rate with minimal power consumption. we propose an algorithm to cache the contents in user device to minimize total energy consumption of user devices. Moreover, user's content activity behavior is retained to minimize user device's energy by dynamic cache space algorithm. Simulation results justify that the proposed scheme can effectively improve cache hit rate and reduce the power consumption of user devices.