Offloading Wireless Cellular Networks via Energy-Constrained Local Ad Hoc Networks

Increasing the capacity of wireless cellular networks is a major concern for network operators. We address the problem of offloading the cellular network via assistance from the mobile terminals to receive an on-demand common content from the base station. The base station unicasts the content to selected mobile terminals that either unicast or multicast it to other mobile terminals over local ad hoc networks. We formulate the resulting problems as linear mixed integer optimization problems that minimize the required number of cellular channels subject to energy consumption constraints at the mobile terminals side. Performance results demonstrate that the achieved gains in terms of reduction of cellular channels depend significantly on the mobile terminals´ energy consumption constraints. For one hop ad hoc networks, significant reduction gains reaching up to 90% and 50% for multicasting and unicasting, respectively, can be achieved, if only 5% of the mobile terminals´ battery level can be spent on cooperation. More gains can be achieved with multihop ad hoc networks, however, at the cost of a higher computationally complex solution.