CAPS: A peer data sharing system for load mitigation in cellular data networks

The exponential growth of mobile data users and services places a heavy burden on the limited wireless bandwidth of cellular data networks. The situation will be exacerbated with the advent of high bandwidth multimedia applications for mobile devices. We propose an architecture called the cellular-based ad hoc peer data sharing system (CAPS) to reduce the load on the cellular network while improving request response times. In CAPS, mobile hosts in a cellular network form an overlay multihop wireless network. This ad hoc network acts as a 'virtual cache' that enables data sharing among mobile hosts. Participating mobiles share the contents of their local caches with other mobiles. A subset of mobile hosts keep track of the location of objects with minimal overhead. Using CAPS, popular objects can be obtained over the ad hoc network without accessing the cellular infrastructure, thereby reducing the load on the cellular network and improving data access latency. We have extensively evaluated the performance of this architecture through simulations in ns-2 across a wide range of scenarios, and find that CAPS reduces the timeouts of the user requests by 70-90% and reduces the load at the base station by up to 60%.