Hierarchical SIR And Rate Assignment On The Downlink Of WCDMA

With the increasing of the QoS and capacity required for the mobile communication, CDMA system adopts a spread spectrum communication technology to solve the problem of spectrum scarcity in the absence of sufficient spectrum resources. For the reason that the third generation mobile communication systems provide a higher data transmission quality of service, WCDMA system with broadband transmission quality comes into being, which is the system based on the traditional CDMA architecture improved. The advent of WCDMA system guarantees the quality of the high-speed data service and decreases the multi-path fading effect during the wireless transmission. Especially, the power control as one of the key technologies in WCDMA system can eliminate the edge effect and the distance effect, reduce the system interference, and enhance the system capacity. Hierarchical cellular system is proposed to overcome the"hot spots"and the"communication blind districts"in the traditional WCDMA cellular system. Therefore, the study of the power control technology in the hierarchical cellular WCDMA system is the issue that the mobile communication systems must be tackled.The main emphasis of this thesis is placed on the power resource and the rate resource in the hierarchical WCDMA system depending on optimizing the radio resource. It is analyzed and explored for the sake of concentrating on the power control and the rate assignment on the downlink in the hierarchical WCDMA system, which involves the cell selection strategy between the macro-cell area and the micro-cell area, the power control algorithm, the rate assignment algorithm, and also provides the relationship between the former two algorithms. In the following, this paper examines a joint control algorithm between the power control and the rate assignment. In addition, the actual wireless environment is considered when the interference problems caused by the downlink path loss and the slow fading exist. In the end, the simulation results indicate that the system performance can be optimized by using the joint control algorithm.