An Adaptive Handoff Algorithm with Accumulated Attempts of User Mobility for Supporting QoS in Wireless Cellular Networks

As the number of mobile users in cellular systems increases, the user mobility becomes the dominating factor for guaranteeing quality of services (QoS). In order to support QoS for mobiles in cellular systems, the concept of accumulated user mobility is combined with the handoff algorithm to reduce the amount of reserving channels (codes) for handoff calls and increase the total carried traffic load. There are many factors that affect the QoS for a handoff algorithm and the mobile velocity, average call duration time, average cell dwell time, and handoff probabilities for each adjacent cell are most frequently mentioned. Thus, the mobile velocity is considered and formulated by the relational function of extenics that is similar to a fussy theory and first applied in wireless networks by this paper. With the cell approaches, the call duration time, etc. can be obtained from user profile and be applied to calculate the handoff attempts of each adjacent cell in current cell. By the accumulated handoff attempts of the six adjacent cells, the appropriate amount of channels (codes) can be reserved for handoff beforehand, and the required QoS is preserved during handoffs occurring. Since both QoS and the number of reserved channels (codes) are the considered issues in the proposed scheme, better system utilization can be achieved.