Research On Edge Cache Strategy For Base Station

Edge caching is an important application of Mobile Edge Computing(MEC),which can enable users to obtain the required content directly from the network edge access point without the need of remote server,reduce the transmission delay and improve the user experience.This thesis studies the edge cache strategy of base station.The main work done in this thesis is as follows:1.Aiming at the optimization goal of maximizing the average cache hit rate,taking the wireless network of a single edge small base station in a macro cell as the research scenario,a cache strategy to maximize the cache hit rate of edge small base stations is proposed.Firstly,the definition of average cache hit rate is given,and the optimization goal is proposed;Then the optimal solution is derived,and the equivalence of maximizing the average cache hit rate,maximizing the popularity and minimizing the average transmission delay is proved theoretically;Finally,simulation comparison is carried out to analyze the average cache hit rate and back-haul link load rate performance of the cache strategy proposed in this thesis and other cache strategies.The simulation results show that in addition to the ideal cache,the cache strategy proposed in this thesis can effectively improve the cache hit rate and reduce the back-haul link load rate compared with other cache strategies.2.Aiming at the optimization goal of minimizing the average transmission delay,taking the wireless network of a single edge small base station in a macro cell as the research scenario,a delay minimization cache strategy based on improved Apriori algorithm is proposed.According to historical request record,find out the association between the user’s request content,take the current time slice request content as the condition,calculate the probability of the user’s request content in the next time slice,find out the most likely request content,and cache this content to the edge small base station associated with the user.When the base station cache space is insufficient,the cache update strategy is introduced to update the cache content.The simulation results show that the running time of the improved Apriori algorithm proposed in this thesis is reduced to a certain extent compared with the classical Apriori algorithm.Compared with the no cache strategy and content history strategy,the proposed cache strategy effectively reduces the average delay of users acquiring content.