Call admission control and performance evaluation in wireless communication networks are essential for system design and operation. The network capacity and admissibility of imperfectly power-controlled multiservice code division multiple access (CDMA) system are studied in this paper. A generalized capacity formula considering traffic activity is derived, based on which a handoff prioritized call admission policy is presented and evaluated using the K-dimensional birth-death process model. System performance in terms of blocking probabilities, resource utilization and average system throughput are demonstrated and discussed in detail as the traffic intensity increases. It is also shown that the system parameters such as outage probability constraint and power control error have great impact on system capacity and performance. Since this work is based on the imperfect power control model, it is more appropriate to the design of practical multiservice CDMA networks.

Improving the efficiency of data dissemination algorithms and protocols to mobile sink remains as an interesting research and engineering issue, especial for large-scale wireless sensor network. As the node energy and resources are limited, theses protocols should meet energy-efficiency, low delay and high delivery ratio requirements. Although an energy-efficient dissemination tree (d-tree) can be constructed with sink mobility, the delayed handoff could lead to suboptimal routing trees for a substantial amount of time as the network grows larger, and also the efficiency heavily relied on the location of the sink, thus it may offset the load balance resulting from hierarchical tree structure. In this paper, we propose an energy efficient routing protocol MGRP (Multi-tier Grid Routing Protocol) which introduces a special hybrid multi-tier structure for data dissemination. MGRP divides the observation areas into square grids, could be different size. Within each grid, we form an optimized cluster which transmit reliable data to its higher tier cluster head, the uppermost cluster head from neighbor grids further negotiate to construct the data d-tree from which the mobile sink can access and send query. Through intensive simulation in a given mobile sink experiment, MGRP performs better in terms of energy consumption and average delay respectively compared to previous protocols such as TTDD (grid-based), SEAD (tree-based) and COSEN (chain-based), under practical conditions, where sensors may die out, but with initial large size

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Due to the recent saturation of the traditional telecom markets, the vendors are shifting their focus on to the vertical markets, including but not limited to oil and mine industries.  This paper is offering a solution for one of the key issues the mine industry is facing. When the accident happen under the mine, the first thing to do is to locate the workers, there are many methods been proposed; however, each has pros and cons. For example, we can use RFID to locate the people, the problem is when there are too many miners at the same spot, the method doesn’t work well; we can use CDMA indoor GPS system to locate the person, however, the base station is not cheap; we can use IEEE802.15 Zigbee system to locate people, but we need huge amount of nodes to cover reasonable size of mine; for these reasons, we propose to use low cost WiFi system to fulfill the task. We introduce IEEE1588 Precision Timing Protocol into the existing WiFi or similar mesh networks, to increase the Time of Arrival ranging accuracy. This way, with limited increasing of the system cost, we satisfy the customer requirements. To prove the concept, Matlab is used to work out the theoretical bit-flow vacation model and the simple linear-ranging algorithms