Two Novel Handover Algorithms with Load Balancing for Heterogeneous Network

Abstract

The demand for wireless resources is increasing at high pace. Heterogeneous networks (HetNets), i.e., network composed by base stations (BSs) with different coverage areas, are useful solutions to cope with this increasing demand. In this paper, we propose two handover (HO) algorithms.First HO algorithm is based on user equipment's (UE's) velocity, UE's position, UE's received signal strength (RSS) from BS and traffic load of BS.In the first phase of the first HO algorithm, UE employs parameters such as the distance of UE from its connected BS, velocity of UE and UE's RSS from its connected BS to determine the necessity of HO. If HO is needed, in the second phase, i.e., HO execution phase, UE selects the new BS based on the distance of UE from BS to which UE approaches, RSS and average traffic load of BS which is advertised through beacon signal. UE uses strength of received beacon signal as RSS. UE transmits the connection request signal to selected BS. Average traffic load means time average of traffic load. UE gets information of its position and its velocity via GPS. Second HO algorithm is based on only UE's RSS from BS and traffic load of BS. This HO algorithm has similar structure as the first one. However, in the first phase, only UE's instantaneous RSS and average RSS which means time average of RSS are employed to determine the necessity of HO by UE. In HOEP, UE selects the new BS based on instantaneous RSS, average RSS and average traffic load of BS. UE transmits the connection request signal to selected BS. A game-theoretic sleep mode algorithm is executed parallel to each HO algorithm in BS. The performance of the two proposed algorithms, such as total number of HOs, UE's throughput and system power consumption is evaluated by means of computer simulation.