Study Of Handover Policy For High-Speed Packet Traffic In WCDMA

Mobile cellular communication grew rapidly along with the development of the communication technology, and was changed from a new technology into a massive industry within less than three decades. Nowadays the third generation mobile communication system (3G) has drawn the greatest attention in the field and WCDMA has already become one of the three standard for the 3g mobile communication system due to its mature technology.Handover is the essential functionality for dealing with the mobility of the mobile users, which can make an on-going call to a different sector or cell and maintain a call in progress across cell boundaries in mobile communication. In WCDMA system all users in the different cells share the same frequency spectrum simultaneously. This makes it possible that WCDMA system support the "make-before-break" soft handover.The thesis represents the implementations of handover in detail, including measurement procedures, handover algorithms and typical signaling procedures. And the impact of soft handover on the downlink capacity is well investigated. The macrodiversity gain offered by the selection combining brings benefits to both capacity and coverage. However, in the downlink, the extra resource consumed by the extra downlink channels increases the total downlink interference level. Especially for the high-speed packet traffic, the soft handover consumed too much radio resources, and brings interference to other users, consequently inducing to the decrease of the system performance.On the basis of these work, a new handover policy is proposed for the high-speed packet traffic. The new handover policy considers the traffic speed of moving UE. The performance of the proposed policy is analyzed through theory and simulation. The simulation results indicate that the resource expend and interference are reduced obviously, which proves the feasibility and the better performance of the proposed handover policy.