Access Selection in Multi-Access Cellular and WLAN Networks
Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
To meet the requirements of future data-rich applications and terminals with improved multimedia, future wireless networks are expected to combine multiple access technologies. When several radio access technologies are available, the assignment and the handover of users among these technologies become fundamental problems. The solutions have a major impact on the system performance as well as on the architecture of future networks. This thesis focuses on access selection criteria in combined wide area coverage cellular and local area coverage Wireless LAN networks. More specifically, involvement of traffic load information on top of signal quality information during selection process is studied. A rough but wide-ranging theory for what gains may be expected in different scenarios is first derived through qualitative reasoning. Then, to verify the theory, a number of different signal quality based and both signal quality and load based access selection algorithms are evaluated in terms of achievable bitrate characteristics and system capacity via simulations. The algorithms are compared for a set of different user behavior scenarios. Results indicate that in scenarios with high traffic load concentrated to the hotspots or cellular access technologies offering bitrates in the same order as WLANs, principles taking signal quality and traffic load into account can provide gains around 20% both in capacity and in achievable bitrates. In scenarios with more evenly distributed traffic or WLAN bitrates exceeding those of cellular, smaller gains are achieved,
Place, publisher, year, edition, pages
2005. , 44 p.
Trita-S3-RST, ISSN 1400-9137 ; 0501
Computer and Information Science
IdentifiersURN: urn:nbn:se:kth:diva-28074OAI: oai:DiVA.org:kth-28074DiVA: diva2:383920