Study on Forward SCH Data Rate Decision Algorithm based on Fast Forward Power Control of CDMA2000 1X

摘要

To provide stable data service on mobile communication network is much different from that on wire communication environment. In case of wire network, channel error rate is much lower than that on mobile network, and the change of error rate depends mainly on the number of users, unless there is any disconnection of resource like physical link. However, the environment of mobile communication is much different from that of wire communication. Mobile network has following differences (features) in comparison to the wire network. First, channel stability in mobile network is much lower than that on wire network due to the change of RF environment. Second, data loss or error rate is much higher on the mobile channel. Third, data rate depends on the subscriber's RF environment and the assigned power, as well as on the bandwidth on the channel. In order to use the existing wire network service, the mobile network should accept the protocol and the protocol structure that are best fit to the wire network. However, it is hard to optimize the protocol and the protocol structure to meet the mobile network. The above-mentioned features make it hard to actually implement the maximum data rate defined in the standard, and the data rate may vary in accordance with the channel environment and the system algorithm. CDMA2000 1X system provides high speed data service as the SCH (Supplemental Channel) Scheduler function changes the data rate, using the data rate decision algorithm, in accordance with the environment. To support this function, the data rate decision algorithm should be implemented to provide stable high speed data service, to use the system resource in maximum efficiency, to give less interference to other channels, and to minimize the system load. This study presents the method and effect of fast forward power control based FFPC(Fast Forward Power Control) data rate decision that could minimize the data throughput drop caused by rapid channel environment change and make up for the unrecovery when the data rate is decided in accordance with forward FCH (Fundamental Channel) power & available power in BTS (Base station Transceiver Subsystem).