Capacity and coverage represent, in addition to QoS, the three main requirements for W-CDMA based 3G mobile communication systems. These are conflicting requirements; i.e., optimizing one will be on the account of the other two. All three, however, depend largely on the interference levels in the system. Improvements on interference are thought to have a decisive effect on the performance of the 3G system and one important interference reduction technique is the utilization of smart antennae. In this paper, we analyze capacity/coverage on the uplink in W-CDMA system utilizing switched beam smart antennae, SBSA, using a simple model of the antenna, while satisfying a certain minimum level of QoS. Limits imposed by both interference from others and the limited uplink power available to any user in the cell are considered. Results of this paper are analytical formulae for capacity/coverage that take into consideration many of the important parameters of either the antennae or the WCDMA system. A sectional view of improvement gains, if any, of either capacity or coverage upon antenna upgrading/downgrading is provided. It is shown that improvements by the directional SBSA of either capacity or coverage, are only attained at high interference conditions; i.e., higher number of users when considering coverage improvement or smaller coverage areas when considering capacity. The higher the interference conditions are the higher gain over side lobes or more beams SBSA are needed to attain improvement.
Multimedia becomes one of the most wanted content in the modern Internet world. Since the Mobile Internet Protocol version 6 (MIPv6) was proposed, many researchers have tried to develop a new protocol based on this technology in order to improve the performance of mobile multimedia services. The world is emerging toward the Mobile Internet Protocol Television (MIPTV) era where people are enabled to watch television while roaming. The MIPTV technology requires high bandwidth and low latency handover. This paper proposes a new model of secure and robust handover with low handover latency, called SeamSAR. The model introduces a new way to perform home binding update and correspondent binding update simultaneously. Simulation results show that the proposed model reduced the handover latency to 63% compared to FMIPv6. Moreover, the secureness of the proposed model was verified using CMurphi simulator.
In network selection problem (NSP), there are now two schools of thought. There are those who think using QoE (Quality of Experience) is the best yardstick to measure the suitability of a Candidate Network (CN) to handover to. On the other hand, Quality of Service (QoS) is also advocated as the solution for network selection problems. In this article, a comprehensive framework that supports effective and efficient network selection is presented. The framework  attempts to provide a holistic solution to network selection problem that is achieved by combining both of the QoS and QoE measures.  Using this hybrid solution the best qualities in both methods are combined to overcome issues of the network selection problem According to ITU-R (International Telecommunications Union – Radio Standardization Sector), a 4G network is defined as having peak data rates of 100Mb/s for mobile nodes with speed up to 250 km/hr and 1Gb/s for mobile nodes moving at pedestrian speed. Based on this definition, it is safe to say that mobile nodes that can go from pedestrian speed to speed of up to 250 km/hr will be the norm in future. This indicates that the MN’s mobility will be highly dynamic. In particular, this article addresses the issue of network selection for high speed Mobile Nodes (MN) in 4G networks. The framework presented in this article also discusses how the QoS value collected from CNs can be fine-tuned to better reflect an MN’s current mobility scenario.
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