Energy consumption problem in mobile personal communications recently becomes popular. Generally, the design and construction of mobile networks are appropriate for peak data traffic, so at leisure time and regions, base station resources will be wasted. Previous researches always tried to reduce the energy consumption of base stations, which takes up about 60% of the total consumption in WCDMA networks. In this work, we tried to focus on the consumption in core networks, which might be ignored in related researches. Considering the sociality of mobile users, plenty of users may concentrate on the same data such as hot news, videos, etc. Because the users with the same interest is huge, so the transmission from the source web server to mobile users of the same redundant data will cause unnecessary energy waste in core networks. In this paper, we design and analysis the method of adding a cache in the base stations, that will store some of the hot information. If the same hot information is needed, data will directly be sent from base stations cache instead of requiring from the content server to save the transmission energy of the core network. A system level simulation under LTE-Advanced Release 11 environment has been done to prove the effectiveness of our design using a simple probabilistic model. From the simulation result, our method can save up to 50% of the total energy consumption considering the consumption of LTE-Advanced core networks.
