Handover in heterogeneous cellular networks with small moving cells

Abstract

Recently, there has been considered the deployment of a heterogeneous cellular network with small moving cells (SMCs) whose base station is moving with its users while serving users. The mobility of SMCs can be exploited to increase spectrum efficiency and user subscriptions as well. In legacy cellular systems, when a vehicle crosses over the cell boundary, the base station (BS) of macro cells need to simultaneously provide fast handover of users in the vehicle at the same time, which may cause large signaling overhead at one time. The deployment of SMCs can alleviate the signaling overhead for the handover when the vehicles are frequently crossing over the cell boundaries in urban environments. In this thesis, we consider the user handover in a heterogeneous cellular network with SMCs. We assume that the BS of an SMC is installed in a vehicle. Conventional handover based on received signal power may not be optimum in this environment. We design a handover algorithm for user handover from the macro cell to the SMC, and vice versa. We consider the handover with or without the use of tagging. In the tagging mode, the handover can be initiated by using a tag (e.g., a bus card). In non-tagging mode, the handover can be initiated by monitoring the change of received signal power, while reducing the signaling overhead without ping-pong effect. We also consider the advantage of the deployment of SMCs in terms of signaling overhead for the handover. Finally, the performance of the proposed handover is verified by computer simulation.