A cross-layer approach for QoS topology control in wireless ad hoc networks
- Authors: Rokonuzzaman, S. K. , Pose, Ronald , Gondal, Iqbal
- Date: 2009
- Type: Text , Conference paper
- Relation: TENCON 2009 - 2009 IEEE Region 10 Conference
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- Description: Wireless ad hoc networks using omni-directional antennas do not scale well due to interference between nearby nodes. Maintaining the QoS of the communications in this type of network is a difficult task. Using multiple narrow beam directional antennas alleviates this problem at the expense of connectivity. Multi-beam smart antennas allow the network topology to be adjusted dynamically by adjusting the beamwidth and beam directions to minimize interference and to maximize the number of possible concurrent network communications. This in turn helps to maintain the QoS of the communications. QoS routing has long been used to meet the user requirements by finding appropriate paths to the destinations. We extend this concept to create an adaptive QoS topology control (AQTC) system using smart antennas. We use a cross-layer approach to control the topology dynamically where the topology control layer sits between the MAC and the routing protocol. The performance of our protocol has been evaluated using extensive simulations. Simulation results show that different topologies for a set of communications perform differently. AQTC always forms a topology to facilitate the current communications and improves the network throughput and end-to-end delay.
A warning based preemptive routing scheme for QoS maintenance in wireless ad hoc networks
- Authors: Rokonuzzaman, S. K. , Pose, Ronald , Gondal, Iqbal
- Date: 2009
- Type: Text , Conference paper
- Relation: PE-WASUN '09 Proceedings of the 6th ACM symposium on Performance evaluation of wireless ad hoc, sensor, and ubiquitous networks
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- Description: Traditional QoS routing protocols find paths that meet the QoS requirements while discovering routes. The chosen route is used while the QoS is met. If the QoS is violated rerouting takes place. Violation of QoS may be unacceptable for delay sensitive traffic. We introduce a preemptive QoS re-routing scheme. The end-to-end delay of packets in each session is monitored and if it seems likely that QoS violation might occur, a preemptive QoS rerouting process is initiated. This helps maintain QoS in dynamic wireless ad hoc networks. Schemes for triggering QoS re-routing are investigated. We have reduced the number of late packets and improved the overall end-to-end delay of the communications.
A cross-layer approach for using multiple radio channels with directional beams in a suburban Ad Hoc network
- 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
Multiple radio channels and directional antennas in suburban ad hoc networks
- 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
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- 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.