Tabu Search Based Approach to Solve the TAs Reconfiguration Problem in LTE Networks

In LTE networks, tracking areas (TAs) design affects the signaling cost of user equipments (UEs) during mobility. Indeed, when the latter are called, the mobility management entity (MME), which records the TA in which the UE is registered, broadcasts a paging message in the UE´s TA to determine the exact cell through which the call should be delivered. When a UE moves to a new TA, a TA update might be performed either to update the MME or the home subscriber server (HSS) depending on whether the move is intra-or inter-MME. TA update and paging result in a significant amount of signaling overhead. The TA design is usually optimized during the network planning phase. However, the mobility of UEs might turn the initial TA configuration inefficient requiring TA reconfiguration. In this paper we use the tabu search (TS) heuristic to solve TAs reconfiguration problem in LTE networks taking into consideration both signaling overhead and reconfiguration cost. We compare our solution with a variation of the genetic algorithm (GA) based solution found in the literature. Preliminary numerical results showed that the TS algorithm outperformed the GA due to the TS different memory mechanisms used to avoid moves that might lead to non-feasible solutions.