Research Doctorate - Doctor of Philosophy (PhD) / The Radio Access Network (RAN) accounts for the major proportion of the UMTS system operating cost. Transmission from radio base station sites contributes a larger part of the RAN operating costs. Selection of suitable transport technologies and proper allocation of network resources are vital from an operator cost optimisation and the Quality of Experience (QoE) points of view. This thesis extensively investigated the performance of a RAN to support multimedia traffic on a HSDPA air interface. Transport network layer of a future RAN could be based on a number of transport protocols such as ATM, IP and Ethernet. With the increasing traffic volume and diversity the efficiencies of IP and Ethernet based RAN could increases significantly due to the use of larger payloads and simpler resource allocation techniques. Also, on IP and Ethernet based links relatively fewer overhead bits are transmitted compared to an ATM based link. Both the IP and Ethernet based links appear to perform better under heavy traffic load conditions. An IP based link could perform better than an Ethernet based link when an IP header compression technique is used. An Ethernet based link is an alternative transport technique for the UTRAN transport network due to its flexibility, economy and bandwidth efficiency. The HSDPA (High Speed Downlink Packet Access) is considered to be one of the initial evolutionary steps to enhance the data rate, and QoS of downlink data and multimedia services for the evolved UMTS network. It can provide high data rate up to 28.8 Mbps on the downlink shared channel using the packet access technique. A HSDPA network can dynamically adjust a connection data rate to match radio conditions to ensure the highest possible data rate for different type of traffic. Inappropriate RAN capacity allocation could lead to low radio resource or RAN resource utilizations. In this thesis, a Markov chain based analytical model has been developed to study the interaction between the air interface and the RAN for a HSDPA network. The analytical model was used to study interactions of RAN transport protocols, flow control techniques and the air interface transmission conditions. Further a simulation model was developed to investigate the relationship between the HSDPA air interface and its RAN parameters. Another important issue in the HSDPA network design is the scheduling algorithm used at the Node-B. A scheduling algorithm plays a key role in allocating a RAN’s network resources. Impacts of scheduling algorithms are studied in this work using a simulation model. Based on the study of the HSDPA air interface and its RAN parameter interactions this work has developed an adaptive resource management algorithm, which uses the measured air interface information to allocate the corresponding connection data rate on the Iub link. The developed algorithm reduces RAN resource requirements while increasing the air interface resource utilization and QoS of connections.

This mini-dissertation reviews present literature to define ICT and SMEs and determine the current situation in South Africa with regard to the use of ICT by SMEs, including possible benefits to SMEs as well as stumbling blocks to adopting ICT. The research consists of collecting data from ten SMEs in Gauteng in South Africa using questionnaires and interviews, to determine how SMEs can use ICT to become more competitive. The mini-dissertation will have a number of chapters: the first chapter will give an overview of the subject. The second chapter will explain the research motivation and methodology while the third chapter will be the literature review, which will explore the topic of ICT and SMEs in depth, with a focus on South Africa. Chapter four will deal with data collection and analysis; the main source of data will be interviews based on structured questions. The fifth chapter will be the discussion and recommendations based on the results of the analysis and the literature review. Chapter Six will be the conclusion. / Dissertation (MIT)--University of Pretoria, 2008. / Informatics / unrestricted