Zu diesem lizenzpflichtigen Artikel gibt es eine Open Access Version, die kostenlos und ohne Lizenzbeschränkung gelesen werden kann. Die Open Access Version kann inhaltlich von der lizenzpflichtigen Version abweichen.
Preisinformation
Bitte wählen Sie ihr Lieferland und ihre Kundengruppe
Recent developments in the telecommunications world - including deregulation, market saturation and increased competition - have put stringent requirements on network operators to minimize the capital and operational expenditures by relying on remote and automatic adaptation mechanisms. Moreover, environmental concerns - such as the Green IT trend - require a minimal footprint of radiating equipment with the minirnal possible transmitted power. Under the wider umbrella of Reconfigurable Radio Networks, this dissertation tackles the problems of radio network planning and selected network elements (antenna tilt, pilot channel power, spreading factor distribution, scheduling, etc...) remote adaptation under the 'moving hotspot' traffic model. The latter introduces a mobility scenario where the distribution of mobile users changes in time and space, with attraction points varying in position and size across time. Whereas a class of traditional mobile users behaves under a Gauss-Markov mobility model, another layer of mobile users follows an attraction point mobility scheme with the size of hotspots varying in size according to a 2-D Gaussian distribution whose standard deviation is equivalent to the radius of the hotspot. Based on this, network planning procedures taking into account this properly of the traffic and the a-priori knowledge that selected network elements can be remotely adapted are developed to find the minimum needed number of base stations through optimization techniques. For the case of Wideband Code Division Multiple Access (WCDMA)-based cellular systems, an increase in the number of base stations not only increases the costs, but could result in harmful inter- and intra-cell interference. The network planning is based on the concept of the Aggregate Map proposed in this work, catching the spatial and temporal traffic characteristics. Moreover, and as a follow-up to the radio planning phase, the adaptation itself is investigated with proposed algorithms to find the optimum rernote electrically antenna tilts and pilot channels power levels across the network. Procedures for near real-time optimization of the adaptation process under various network loads are investigated. A distributed architecture to enable the remote adaptation process is introduced based on a Coupling Matrix specifically defined for this work, taking into consideration the antenna tilts and the pilot channels power. Thresholds for adaptation initiation based on various key performance indicators are presented. The near real-time adaptation algorithms are developed for dedicated voice channels (DCH), shared high speed downlink packet access channels (HSDPA) and dedicated high speed uplink packet access channels (HSUPA). The properties of each type of channels are taken into account, such as the transmission power and channels allocation for HSDPA and the spreading factor distribution for HSUPA. Since this is a measurement based approach for autonomous adaptation, the properties and effects of uplink signaling are investigated. The results show a significant reduction in the number of needed base stations for pre-defined coverage and capacity levels in the network planning exercise, and a reduced transmission power in both uplink and downlink together with higher capacity and coverage levels in the near real-time adaptation phase.