This paper introduces a novel cross layer medium access control protocol for multiple beam antennas to fully utilize their multiple-beam-forming capability. Our protocol, explicit synchronization via intelligent feedb...
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This paper introduces a novel cross layer medium access control protocol for multiple beam antennas to fully utilize their multiple-beam-forming capability. Our protocol, explicit synchronization via intelligent feedback (ESIF), uses feedback from neighboring nodes to synchronize data communication at multiple beams. ESIF exploits routing information to guarantee long-term fairness and minimize the energy and latency overheads. Unlike previous works on directional antennas that discuss range extension, we focus on optimal spatial reuse. Simulation results demonstrate that ESIF outperforms other on-demand access schemes based on IEEE 802.11 DCF for multiple beam antennas
In a wireless ad hoc networks where all mobile nodes (MNs) have the same transmission range and the MN density is sufficiently high, the actual hop count between any two MNs is proportional to the distance between the...
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In a wireless ad hoc networks where all mobile nodes (MNs) have the same transmission range and the MN density is sufficiently high, the actual hop count between any two MNs is proportional to the distance between them. This paper shows the relation between distance and hop count first. Then, based on the relation, the required hop count between two given MNs is estimated. With the distribution of distance between pairs of MNs, this paper also suggests the optimal transmission power of MNs, which can guarantee delay constraints of a requested ratio of connections in an entire network. All problems are investigated in both a two-dimensional and a three-dimensional area. Simulation results substantiate the accuracy of the proposed approximation methods. The errors of the hop count estimation method are just 0.88% and 2.33% in a 2D and 3D area.
In this paper we present a design of a medium access control protocol that allows the utilization of unused licensed spectrum of deployed wireless cellular systems (Primary System) by an overlaid multi-hop ad hoc netw...
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In this paper we present a design of a medium access control protocol that allows the utilization of unused licensed spectrum of deployed wireless cellular systems (Primary System) by an overlaid multi-hop ad hoc network (Secondary System). The basic design principle is that the secondary operates in a non-intrusive manner and does not interact with the primary. We address a number of architectural challenges pertinent to this networking environment, and evaluate the performance of the MAC. Our performance evaluation results show that, in a single-hop ad hoc network, the proposed MAC transparently utilizes 75% of the bandwidth left unused by the primary, while, in the multi-hop cases, due to spatial reuse, the bandwidth utilization can be significantly higher.
Historically, a large number of small and cheaper sensors are deployed to form a sensor network. This paper provides rationale behind using an aggregate logical sensor unit (ALSU) as a building block in a Wireless Sen...
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Historically, a large number of small and cheaper sensors are deployed to form a sensor network. This paper provides rationale behind using an aggregate logical sensor unit (ALSU) as a building block in a Wireless Sensory Information network (WSIN). In this architecture, a single ALSU is composed of many off-the-shelf sensor nodes in the manner similar to the Beowulf cluster concept. The highly capable, cost effective and flexible ALSUs built in this manner from several smaller physical sensor nodes, would enable high computation power and built-in reliability for sensor applications. The objective of this paper is to provide an alternative where energy and computation is not a limiting factor in order to achieve the operational objectives of WSIN applications. This paper highlights critical issues that need to be addressed in developing a framework where each ALSU could have the capability to perform required operations as dictated by an underlying application
Deafness is considered as a major medium access problem arising due to directional communication in beamforming antennas. In this paper, we provide a novel algorithm for mitigating deafness (AMD) in such antennas. The...
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ISBN:
(纸本)9781424400027;1424400023
Deafness is considered as a major medium access problem arising due to directional communication in beamforming antennas. In this paper, we provide a novel algorithm for mitigating deafness (AMD) in such antennas. The algorithm extends the directional virtual carrier sensing mechanism by dynamically maintaining parameters for every beam. AMD can easily be implemented with the existing medium access control (MAC) protocols for multiple beamforming antennas. Simulation results show that considerable performance gains can be achieved when the proposed algorithm is employed by the existing MAC schemes.
A growing need for ubiquitous connectivity has motivated the integration of various wireless technologies such as cellular systems, WLANs and MANETs. In this paper we introduce the integrated routing protocol (IRP) th...
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A growing need for ubiquitous connectivity has motivated the integration of various wireless technologies such as cellular systems, WLANs and MANETs. In this paper we introduce the integrated routing protocol (IRP) that exploits topology information obtained by cellular base stations and WLAN access points in the route discovery and maintenance in a heterogeneous wireless access network. IRP also provides connectivity to the cellular network and/or WLAN hotspots through the multi-hop routing by allowing out of coverage users to maintain routes to Gateway Nodes (GN). We provide a simulation study of IRP with two different link quality metrics, number of hops and a new integrated metric based on the expected transmission time (ETT). Our results show that IRP improves the network coverage and capacity and allows connectivity alternatives that are not supported by other integrated solutions
Over the past few years, wireless local area networks (WLANs) have gained an increased attention and a large number of WLANs are being deployed in universities, companies, airports etc. Majority of the IEEE 802.11 bas...
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Over the past few years, wireless local area networks (WLANs) have gained an increased attention and a large number of WLANs are being deployed in universities, companies, airports etc. Majority of the IEEE 802.11 based WLANs employ distributed coordination function (DCF) in wireless access points (AP) to arbitrate the wireless channel among Wireless Stations (STAs). However, DCF poses serious unfairness problem between uplink and downlink flows. To overcome this unfairness problem, we propose a simple enhancement to the IEEE 802.11 DCF which provides priority to the AP and thus enables it to acquire a larger share of the channel when required. We have demonstrated the unfairness problem through systematic measurements in an experimental test bed of WLAN using the legacy 802.11 DCF. We also developed analytical models to calculate the throughput of AP and the STAs and verify these results through thorough simulations in ns-2. We observe that our simulation results find in good agreement with our analytical models. Results show that our proposed enhancement achieves a fair distribution of bandwidth and improves the throughput (by nearly 300%) for the downlink flows as compared to the DCF, without severely affecting the performance of uplink flows
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