List of Titles

A cross-layer approach for using multiple radio channels with directional beams in a suburban Ad Hoc network

- Rokonuzzaman, S. K., Pose, Ronald, Gondal, Iqbal

Authors: Rokonuzzaman, S. K. , Pose, Ronald , Gondal, Iqbal
Date: 2008
Type: Text , Conference paper
Relation: Australasian Telecommunication Networks and Applications Conference
Full Text: false
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Description: The capacity of wireless ad hoc networks can be increased by using multiple radio channels. But due to interference the capacity is still not fully utilized. This is caused by the limited number of available radio channels. The interference problem can be reduced using directional beams instead of omni-directional beams. This paper presents a novel cross-layer approach to use multiple radio channels with directional antennas. We are using three different radio channels. Each node has three fixed directional beams having fixed beamwidth and with different radio frequency. Two nodes can communicate when both the sending and receiving beams are pointing towards each other using the same frequency channel. In this study the directions of beams cannot be changed dynamically. A modified version of Ad hoc On-demand Distance Vector (AODV) routing protocol has been used. Simulation results show that our approach outperforms other methods using three different radio channels with omni-directional antennas

A framework for a QoS based adaptive topology control system for wireless ad hoc networks with multibeam smart antennas

- Rokonuzzaman, S. K., Pose, Ronald, Gondal, Iqbal

Authors: Rokonuzzaman, S. K. , Pose, Ronald , Gondal, Iqbal
Date: 2008
Type: Text , Conference proceedings
Full Text: false
Description: Wireless ad hoc networks are self-configurable distributed systems. One of the major problems in traditional wireless ad hoc networks is interference. The interference could be reduced using smart directional antennas. In this study, multibeam smart antennas have been used. When using this type of antenna, two nodes can communicate when both the sending and receiving beams are pointing towards each other. Also, a node can only communicate with a subset of nodes in its neighborhood depending on the number of beams and their beamwidth. Thus, the network topology needs to be dynamic in this case, and by controlling the topology network, performance can be increased. In this paper, we present a framework of a cross layer approach of topology control that interacts with the routing layer and MAC layer and meets the required QoS of different data streams. The approach is fully distributed. When the network is initialized, the algorithm builds an initial connected topology and the routing algorithm uses this topology to find paths for the current communications. Then, depending on the network scenario, current communications and the required QoS, the topology control layer changes the topology to optimize the network performance. This study concerns suburban ad hoc networks (SAHN) where nodes tend to be fixed and are aware of their locations.

Context aware vertical soft handoff algorithm for heterogeneous wireless networks

- Yang, Kemeng, Gondal, Iqbal, Qiu, Bin

Authors: Yang, Kemeng , Gondal, Iqbal , Qiu, Bin
Date: 2008
Type: Text , Conference paper
Relation: Proceedings of the 68th IEEE Vehicular Technology Conference p. 1266-1270
Full Text: false
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Description: Soft handoff in WCDMA systems allows multi connection between the user and base stations during handoff, in contrast to single connection in hard handoff. But multi connection flexibility leads to a trade-off between quality of service for the user and the system downlink capacity. The heterogeneous wireless networks consist of WCDMA and WLAN systems, which operate at different frequency with no direct interference. Therefore, a vertical soft handoff between downlink shared channels from WCDMA and WLAN will not suffer similar side effects as the horizontal soft handoff in WCDMA systems. In this paper, we present an analytical framework for vertical soft handoff and propose a context-aware vertical soft handoff algorithm (CAVSH) for heterogeneous wireless networks. CAVSH considers four user and system context parameters such as user required bandwidth, user traffic cost, access network utilization, and signal to interference-and-noise ratio (SINR). The results show that the proposed CAVSH can provide the system with lower dropping probability, lower average cost to the user and higher throughput, as compared with vertical hard handoff.

Gene expression imputation techniques for robust post genomic knowledge discovery

- Sehgal, Muhammad Shoaib B, Gondal, Iqbal, Dooley, Laurence

Authors: Sehgal, Muhammad Shoaib B , Gondal, Iqbal , Dooley, Laurence
Date: 2008
Type: Text , Book chapter
Relation: Studies in Computational Intelligence p. 185-206
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Description: Microarrays measure expression patterns of thousands of genes at a time, under same or diverse conditions, to facilitate faster analysis of biological processes. This gene expression data is being widely used for diagnosis, prognosis and tailored drug discovery. Microarray data, however, commonly contains missing values, which can have high impact on subsequent biological knowledge discovery methods. This has been catalyst for the manifest of different imputation algorithms, including Collateral Missing Value Estimation (CMVE), Bayesian Principal Component Analysis (BPCA), Least Square Impute (LSImpute), Local Least Square Impute (LLSImpute) and K-Nearest Neighbour (KNN). This Chapter investigates the impact of missing values on post genomic knowledge discovery methods like, Gene Selection and Gene Regulatory Network (GRN) reconstruction. A framework for robust subsequent biological knowledge inference has been proposed which has shown significant improvements in the outcomes of Gene Selection and GRN reconstruction methods.

Multi-dimensional adaptive SINR based vertical handoff for heterogeneous wireless networks

- Yang, Kemeng, Gondal, Iqbal, Qiu, Bin

Authors: Yang, Kemeng , Gondal, Iqbal , Qiu, Bin
Date: 2008
Type: Text , Journal article
Relation: IEEE Communications Letters Vol. 12, no. 6 (2008), p. 438-440
Full Text: false
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Description: Vertical handoff in next generation heterogeneous wireless networks is a multi-dimensional issue. In this article we propose a multi-dimensional adaptive SINR based vertical handoff algorithm (MASVH) which uses the combined effects of SINR, user required bandwidth, user traffic cost and utilization from participating access networks to make handoff decisions for multi-attribute QoS consideration. Simulation results confirm that the new MASVH algorithm improves the system performance in terms of higher throughput and lower dropping probability, as well as reduces the user traffic cost for accessing the integrated wireless networks.

Multiple radio channels and directional antennas in suburban ad hoc networks

- Rokonuzzaman, S. K., Pose, Ronald, Gondal, Iqbal

Authors: Rokonuzzaman, S. K. , Pose, Ronald , Gondal, Iqbal
Date: 2008
Type: Text , Conference paper
Relation: 2008 International Symposium on Parallel and Distributed Processing with Applications p. 379-386
Full Text: false
Reviewed:
Description: The Suburban Ad Hoc Network (SAHN) is a cooperative ad hoc wireless mesh network. Nodes are owned and operated by end-users without reliance on central infrastructure. It provides symmetrical bandwidth allowing peer-to-peer services and distributed servers. We minimize the use of scarce unlicensed RF spectrum supported by Smart Antenna technology. RF interference in such networks and techniques and strategies to reduce it are examined. Traffic is spread across multiple frequency channels, and multiple directional beams to achieve improved spatial re-use. We focus on the control of smart antennas rather than their design. By dynamically adjusting our network topology using Smart Antennas and dynamically re-routing current communications we optimize the network for its current traffic needs.

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