Research & Implementation Of Radio Link Layer To Transmit HSPD In The Cdma2000 1X System

With rapid improvements of mobile terminal users' requirements to services of Internet and Multimedia traffic, implementation and optimization of supports to HSPD(High Speed Packet Data) traffic of the system have been becoming a hot issue in mobile communication fields. CMT is based on both ALL-IP and cdma2000 technologies. Dealing with HSPD in the WAS sub-system is performed by Mux and Qos Sublayer and Radio Link Protocol(RLP) in radio link layer in CMT.Firstly, we introduce two traits of the CMT network architecture, air interface of cdma2000 and the function and architecture of WAS. Secondly, standards of Mux and QoS Sublayer and Radio Link Protocol are researched, while difficulties are listed. Thirdly, good solutions are proposed and discussed detailedly herein, which is to difficultis and key problems during the implementation of these two standards. Lastly, we emphasis on several key problems when designing and implementing the Shared SCH, which is an important and efficient method to optimize the HSPD traffic in the system and improve the throughput of the base station.The main work of this dissertation is as follows:1. During implementation of the Multiplex Sublayer, both Psudo Interrupt-trigger mechanism for timing of the Multiplex Sublayer and Inquire-Resolicit mechanism for interface between the Multiplex Sublayer and upper layers are proposed. The former which combines the hardware interrupt and software inquiry, not only solves the timing problem of the Multiplex Sublayer, but also synchronizes the timing between the Multiplex Sublayer and the Physical Layer. The latter mediates conflicting requests from competing services within the Multiplex Sublayer so as to multiplex them smoothly. At the same time, rules about selecting MuxPDU categories and the method of supervising the situation of reverse link are given, which improve the efficiency of the physical channel, the sector throughput and abilities dealing with accident errors.2. During implementation of RLP, both the method dealing with received RLP frames of abnormal sequence number and the method judging and dealing with RLP delayed frames are proposed. The former waits the interval of several frames to avoid incorrectly process when frames with abnormal sequence number are received. The latter corrects the wrong method dealing with delayed frames in the RLP standard. At the same time, methods of selecting best format frames and bypassing the SYNC exchange which is not necessary and dealing with received resequencing buffers during the initialization of RLP are given. The throughput of HSPD is greatly improved by these methods.3. During implementation of Shared SCH, a feedback mechanism of SCH for soft handoff of HSPD is proposed for Shared SCH. Combining buffer queues and the feedback mechanism, this method solves scheduler problems because of Shared SCH of the target WAS. At the same time, methods of switching the SCH active set andassigning frame-offset for Shared SCH are given. And, packet data scheduler algorithms and power control options for Shared SCH are discussed. All listed mechanisms and methods above were implemented in CMT and has been passed lots of function tests and the 1-2 years' verification by the actual system running.