| 3G mobile communication standard should not only to meet the need of voice and low-speeddata services for most users, but also the need of high-speed data packet services.3G mobilecommunications adopt the method of CDMA communication, and the capacity of CDMAcommunication system is limited by the interference, and the system capacity could be increased bythe reducing of that interference. The TDMA method is adopted in the downlink of1x EV-DOsystem to improve the packet data transfer rate, but the CDMA technology is still used in WCDMAsystem. Those two kinds of different technologies were to be used respectively in the parts of highspeed data transmission for1x EV-DO and WCDMA. The rationality of using different techniquesis given in this thesis for the aspects of modulation.1x EV-DO business channel contains16CDMAchannels in16order Walsh code for improving the data rate of packet transmission. The possibleproblem resulting from16CDMA channels being used in the1x EV-DO system would be studiedin this thesis.The performance of capacity and wireless coverage for cdma2000and WCDMA systems isstudied in this thesis on the basis of predecessors’ research through the contrast method, theconclusion provides some reference for the network planning. Firstly, the paper analyzes the rate offorming process, and the calculation of the nominal rate in1x EV-DO forward link. Provide therationality of using TDMA mode in1x EV-DO forward link by researching the modulation method,however, there is no this way in WCDMA. Secondly, comparative analysis between cdma2000andWCDMA systems about the coverage radius and the maximum number of users in their uplink anddownlink is presented. Given the limit of capacity in the reverse link and the simulation method,studied the1x EV-DO down link budget, combined with wireless propagation model analysiscovers, draw some conclusions with reference value. Last, the throughput for1x EV-DO system isstudied, namely the system throughputs under different scheduling algorithms. |
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