Multimedia services in DS/CDMA cellular networks: Erlang capacity and scheduling schemes

Broadband wireless networks are being envisioned to provide ubiquitous multimedia services to mobile users. Supporting multimedia services along with the legacy wireless applications such as voice in an integrated networking framework requires a new network infrastructure and the provision of Quality of Service (QoS) guarantees. This thesis addresses QoS issues in CDMA networks, specifically, Erlang capacity and blocking probability of a CDMA system with multimedia traffic and the design of several radio link-layer scheduling schemes employing service differentiation, and providing QoS guarantees.;A new method is proposed for calculating the Erlang capacity of a DS/CDMA system that can accommodate different traffic sources with variable transmission bit rates. In this approach, each source is modelled using a continuous-time Markov process. The evaluation is illustrated for networks with both homogeneous (one class) and heterogeneous (multiple classes) traffic sources. Imperfection in power control due to channel impairments is also considered. Such a model can capture traffic burstiness and yield more realistic results.;A transmission rate scheduling scheme is proposed that can provide either absolute or relative QoS guarantees for different service classes. The proportional differentiated services model is introduced which enables the network operator to tune QoS ratios among these classes independent of the class loads. An optimization problem is also proposed that maximizes the transmission rate allocations among Mobile Stations (MSs) while ensuring the stability of packet queues and meeting the transmit power level constraint. Analysis and simulation results are used to illustrate the viability of the scheduling scheme which could be applied in the emerging Differentiated Services (DS) Internet.;A load-based transmission rate (LTR) assignment scheme is introduced for non-real time data services in an integrated voice/data network. The LTR scheme takes into account session arrival processes and optimally determines the required transmission rate for each session so as to minimize the overall average packet transfer delay. It is shown that the average packet transfer delay of LTR is significantly lower than that of the conventional traffic-based grouping transmission (TGT) scheme.;A reservation policy combined with a number of centralized dynamic priority based packet-level schedulers is proposed for providing soft QoS guarantees for multimedia traffic while achieving a high channel utilization.;A fair queueing architecture is proposed which allows many of the proposed wireline fair queueing algorithms to be used in wireless CDMA systems.;Finally, a new scheduling algorithm "Wireless Deficit Round Robin (WDRR)" is proposed. (Abstract shortened by UMI.)...