Multibeam schemes and dynamic channel assignment in cellular mobile and personal communications

This dissertation considers the application of switched multibeam schemes and dynamic channel assignment for emerging cellular mobile and personal communication systems. The use of switched multibeam schemes can improve system performance. Dynamic channel assignment (DCA) can be used to increase channel reuse. A combined approach provides even better performance in communication link quality and system capacity. Analytical models based on multidimensional birth-death processes for analysis of teletraffic performance are developed and theoretical performance characteristics are calculated.; The first contribution proposes and analyzes sectorized switched multibeam cellular systems for improvement of system capacity. One approach is the reuse of channels in different beams at the same site. A 120°-sectored cellular system with cluster size of seven is considered. Each sector is covered by three directional beams. Channels can be reused in two non-adjacent beams of a sector as long as the co-channel interference is maintained below the required level. Specific channels are allocated to each sector as in fixed channel assignment (FCA). There is no permanent set of channels allocated to each beam. Channel resources can be shared between beam of the same sector. DCA between beams within a single sector is used. Limitations due to co-channel interference are analyzed. System capacity is increased significantly by using this approach.; Another approach is the reduction of frequency reuse distance for increased spectrum efficiency. A 120° -sectored multibeam cellular system with two beams in each sector and a cluster size of four is investigated. The use of directional beams reduces the reuse distance (cluster size is reduced from seven for traditional 120°-sectored scheme to four for 120°-sectored multibeam scheme) while the co-channel interference is maintained within the acceptable range by appropriate channel assignment and network coordination. Simultaneous use of the same channels in beams of different co-channel sectors that will cause excessive cochannel interference to another co-channel sector must be precluded. This indicates that the use and assignment of channels to calls in a sector are coupled with the use and assignment of channels in its neighboring co-channel sectors. DCA is used across multiple sectors. Smaller blocking and forced termination probability are obtainable in comparison with the traditional six-sector cellular system.; The second contribution proposes and analyzes a configuration for delivering multiple services. We consider that different services require different link qualities, thus different Carrier-to-Interference Ratio (CIR). The scheme supports different services by providing channels with different CIR. Channel resources are shared between different services in a way that services demanding low fink quality have access to high CIR quality channels due to unavailability of low CIR quality channels. DCA is used to improve channel reuse and to allocate different CIR quality channels within a channel layout which incorporates several frequency reuse patterns. An analytical model which takes into account the multiple types of calls is developed. Theoretical traffic performances for different types of services are calculated.