Çoklu ortam servislerini sağlamak için spektrumu verimli telsiz paket veri sistem tasarımı

ABSTRACT Efficient wireless packet data access is possible by exploiting the multi-user diversity using an opportunistic multiple access system that allocates system resources to one user at a time while employing adaptive coding and modulation. Based on this outcome, recently the IS-856 system was developed. A scheduling algorithm provides resource allocation in the IS-856 system, and its proper design is perhaps one of the most crucial aspects for ensuring good system performance. The thesis presents a number of such algorithms, five of which are novel. The proposed algorithms appear to have the best overall performance of achieving high system throughput without diverging much from the optimal latency performance. The thesis shows that the IS-856 system can easily be adjusted to provide a multitude of services, each with different QoS requirements. Extensive performance evaluations show that good system performance can be maintained in the multi-service scenario. The thesis also presents the means of providing multicast service provisioning in the IS-856 system. The selection of the scheduling algorithm influences not only the system throughput but also the average delay exposed by users in between successive accesses to the system. The thesis proposes new access method, Two Users At A Time System, and its scheduling algorithms which decrease latency figures approximately 50%. Present 3G carrier technologies cannot separately cover all the demands of the end- user in terms of coverage, bandwidth, quality of service (QoS) and cost. The 4G networks are heterogeneous networks that eliminate previous technologies drawbacks and contain large number of different access methods. Therefore, the thesis demonstrates new access methods are needed to combine some of the existing network topologies. These access methods provide wireless data connectivity for nomadic users when away from their offices and homes. The envisioned corporation increases the IS-856 network throughput more than 50%. IV