Study On Key Technologies Of High-Speed Packet Radio Network

Recent progress in Internet and mobile communication technologies has attracted much attention, which leads to an intensive research to extend data services into wireless mobile environment. Packet radio network can provide wireless communication and data distribution among mobile terminals. It plays an important role in military and commercial areas and is interpreted as an integral part of future抯 personal communication systems. The high-speed packet radio network (HSPRN) is critical to meeting the requirements for wide-band, rapidly deployable and robust information systems, studies on which are more challenging. In this dissertation, some of the key technologies in HSPRN are investigated, addressing study on low layer protocols, performance of M-ary orthogonal spread spectrum system, and the experimental system design for HSPRN. The major achievements are outlined as follows. Chapter 2 studies the performance of integrated data/voice services in HSPRN and thoroughly discusses the influence of different low layer protocols on the performance of services and network, on the basis of which some new low layer protocols to support integrated data/voice services are presented. Simulation results show that low layer protocols play an important role in the performance of the network and the protocols presented significantly improve the performance of data/voice integration. Even in case of heavy traffic, these protocols can provide acceptable quality of voice service for a limited number of users. Chapter 3 considers the performance of a multi-hop packet radio network employing adaptive antennas at the mobile stations. A simple adaptive beam-forming policy is presented. In addition, the AD-ALOHA protocol for media access control and the adaptive protocol architecture with adaptive antenna technology are proposed. Analysis and simulation indicates that mobile stations in packet radio networks employing mobile adaptive antennas can offer a significant performance enhancement when compared with their omnidirectional counterparts. Chapter 4 studies the performance of M-ary orthogonal spread spectrum RAKE receivers in multipath fading channel. The expressions for the error probability are derived for BPSK modulated M-ary orthogonal spread spectrum systems employing coherent RAKE receivers in Rayleigh fading channel, which take into account the effect of chip timing error and carrier phase error. Non-diversity and three types of diversity 1? schemes are considered: selection diversity, equal gain diversity combining, and maximal ratio diversity combining. The close-form approximations are derived for the average error probabilities. And the channel characteristics, diversity schemes, and synchronization errors?effects on the performance are discussed. Finally, the computer simulation agrees with the results obtained. A pilot channel aided M-ary orthogonal spread spectrum system for IISPRN is presented in chapter 5, where the synchronization control information is modulated on in-phase carrier and the data information on orthogonal carrier. The data channel is spread by the Walsh-sequences, which can be demodulated under the despread output of the pilot channel spreading by in sequences. In addition, the hardware design of the reconfigurable transceiver for M-ary orthogonal spread spectrum system is presented, employing some new ASICs and...