Energy Optimization for Bidirectional Multimedia Communication in Unsynchronized TDD Systems

Energy efficiency is one of the main system resources that has to be optimally allocated, due to its impact on the amount of generated interference and the battery life for multimedia communication. In this paper, we concentrate on the time-division duplexing (TDD) option and how to efficiently allocate energy on both uplink (UL) and downlink (DL) channels that share the same bandwidth but over different time intervals. One of the main advantages of TDD is the possibility for load compensation between UL and DL, by allocating a larger percentage of time for the operation in DL if the system is congested in DL, and vice versa. While this allocation can be done on each cell independently, the result is that adjacent cells would have a different compensation value, thus generating cross interference, which decreases the system performance, mainly on the cell-edge users. This paper presents an energy allocation in order to compensate the unsynchronization in the percentage allocation, where the objective is to guarantee minimum quality of service satisfaction at all receivers, while the least amount of energy is consumed.