Transmission Theory And Method In Content Cache Based Cloud Radio Access Networks

Wireless communication technology has been switching from voice traffic to data traffic. To satisfy the demand for high traffic, connection density and mobility of users, cloud radio access networks have been proposed. In 2020 and the future, the increasing data traffic, device connections and various service demand of users posed new challenges to the further improvement of wireless access system. Moreover, the capacity of fronthaul links are constrained and the delay performance of users who received data service are urge to be decreased. In recent years,content caching based on edge cloud has been widely applied. Compared with traditional centralized signal processing, it decreases the heavy burden on fronthal. Thus, the transmission theory and method in cloud radio access networks (C-RANs) based on content caching shows significant values in both academic research and practical application.This thesis studied the transmission theory based on content caching, in addition, it analyzed transmission method considering delay performance of users.Firstly, the remote radio frequency unit and user location distribution in cloud wireless access network are described by stochastic geometrical theory. The mathematical model is constructed and the theoretical expression is derived for two performance indexes of effective capacity and energy efficiency. Using Monte Carlo and numerical simulation to verify the theoretical accuracy, and to analysis the improvement of network performance.Secondly, because the average effective capacity of content transmission is determined by the RRH and the allocation of radio resource blocks, the service remote radio head (RRH) and the wireless resource unit form a coalition formation game problem, and the joint optimization is studied to further analyze the clustering content cache performance gains.Finally, to further measure the improvement of the ergodic rate and the reduction of transmission delay in the cache deployed cloud wireless access network, on the basis of balancing caching capacity and caching hit rate, the transmission method is analyzed for delay performance. This paper proposed a content transmission mechanism based on queuing theory, and studied the system waiting delay and delay rate on the basis of"cluster" cooperation. The simulation results showed that the theoretical analysis is accurate, and the joint allocation algorithm proposed in this paper is effective. It is shown that changing the content transmission method can greatly enhance the performance of the system under the premise of guaranteeing waiting delay.