Abstract-Orthogonal Frequency Division Multiplexing Access (OFDMA) has been increasingly deployed in various emerging and evolving cellular systems to reduce interference and improve overall system performance. However, in these systems InterCell Interference (ICI) still poses a real challenge that limits the system performance, especially for users located at the cell edge. Inter-cell interference coordination (ICIC) has been investigated as an approach to alleviate the impact of interference and improve performance in OFDMA-based systems. A common ICIC technique is interference avoidance in which the allocation of the various system resources (e.g., time, frequency, and power) to users is controlled to ensure that the ICI remains within acceptable limits. This paper surveys the various ICIC avoidance schemes in the downlink of OFDMA-based cellular networks. In particular, the paper introduces new parameterized classifications and makes use of these classifications to categorize and review various static (frequency reuse-based) and dynamic (cell coordination-based) ICIC schemes.

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Abstract. Wireless Sensor Networks (WSNs) consist of a large number of nodes networked via wireless links. In many WSN settings, sensor nodes are deployed in an ad hoc manner. One important issue in this context is to detect the boundary of the deployed network to ensure that the sensor nodes cover the target area. In this paper, we propose a new algorithm that can be used to discover the boundary of a randomly deployed WSN. The algorithm does not require the sensor nodes to be equipped with positioning devices and is scalable for large number of nodes. Simulation experiments are developed to evaluate the performance of the proposed algorithms for different network topologies. The simulation results show that the algorithm detects the boundary nodes of the network with high accuracy.

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