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This paper proposes a multi-channel MAC protocol that provides QoS for ad-hoc networks based on the IEEE 802.11 DCF mode. The IEEE 802.11 standard gives methodologies and examples for contention-based distributed coordination systems for only a single channel. To overcome this limited channel usage, many studies on how it works in multi-channel environment have been performed. The IEEE 802.11e has...
In this paper, we propose a HDTV transmission over IEEE802.3ac 4 × 5 MIMO WLAN System. The proposed system employs the next generation wireless LAN system based on IEEE802.3ac specification. It reaches more than 33 meter propagation distance by using 80 MHz of bandwidth on the 5 GHz band. In this system, video data is compressed by JPEG 2000 with error resilience tools. These tools improve error performance...
The main goal of the IEEE 802.11n standard is to achieve more than 100Mbps of throughput at the MAC service access point. This high throughput has been achieved via many enhancements in both the physical and MAC layers. A key enhancement is frame aggregation which reduces the overheads and increases the channel utilization efficiency. The MAC layer defines A-MSDU and A-MPDU frame aggregations in which...
We study myopic sensing policy for an opportunistic communication system in which the states of channels evolve as independent Markov chains. A Secondary User (SU) takes one channel to sense and access in each time slot by myopic sensing policy. In the myopic policy, SU ignores the impact of the current action on the future decisions and tries to maximize the expected immediate reward. We propose...
Satellite communication has become important in the current global data communication due to its large coverage area. Satellite links are affected by two major concerns: long propagation delays, and relatively high error rates. Standard TCP congestion control variants were not designed to address these challenges. They generally depend on round trip times (RTTs), and hence suffer heavily if the RTTs...
This paper proposes a cross-layer design (CLD) framework called channel-aware buffer unit multiple access (C-BUMA) for improving wireless local area network (WLAN) performance. In the framework, the radio propagation (i.e. PHY layer) is combined with the medium access control (MAC) protocol for packet transmissions. By sharing channel information with the MAC protocol, the approach reduced unnecessary...
Abstract-In IEEE 802.11 standard, the use of multi-channel is one of the most important characteristic features contributing to the improvement of the overall network throughput. However, the channel utilization based on the use of multi-channel is relatively low because most medium access control (MAC) protocols were designed based primarily on the application of non-overlapping channels. This paper...
This paper introduces a novel cognitive multipath multi-channel routing protocol (CMMRP) for mobile ad-hoc networks. It is designed for a multi-channel environment where nodes can simultaneously use multiple interfaces to transmit packets over different frequencies. It employs cognitive functions to make nodes intelligently select multiple node-disjoint, edge-disjoint and frequency- disjoint paths...
Transmitting request-to-send (RTS)/clear-to-send (CTS) packets at the maximum power and data/ACK packets at the minimum power creates a asymmetrical link which has been proven to increase the collision probability. In this paper, we first discuss the deficiency of uncontrolled asymmetrical transmission power in multi-channel environments. We then propose a symmetrical power control for multi-channel...
Recently, it has been shown that CSMA algorithms which use queue length-based link weights can achieve throughput optimality in wireless networks. In particular, a key result by Rajagopalan, Shah, and Shin (2009) shows that, if the link weights are chosen to be of the form log log(q) (where q is the queue-length), then throughput optimality is achieved. In this paper, we tighten their result by showing...
To tackle control channel saturation problems, this paper proposes OMA, an asynchronous duty cycle based multi-channel MAC protocol with opportunistic media access for wireless sensor networks. By adopting opportunistic media access, OMA effectively alleviates, if not completely eliminates, control channel saturation problems. More importantly, OMA is fully distributed with no requirements of time...
Vehicular Networks are more and more considerable recently. With the rapid advance of information technology, it becomes easy to support low cost inter-vehicle communication. In particular, the demand for delay sensitive applications, such as streaming media distribution, is increasing. However, due to the high mobility, links between roadside units and wireless nodes are intermittent, unreliable...
One of the crucial challenges in practical wireless networks is how to provide robust communication over fading channels. Recently, cooperative communications have emerged as a promising approach to achieve spatial diversity and thereby reduce the negative effects of fading on wireless channels. Nevertheless, a few existing works indicate that deploying cooperative relays in large-scale wireless networks...
Single-radio mesh routers operating on a single channel suffer from low throughput due to collisions. Equipping mesh routers with multiple radios operating on non-overlapping channels can significantly improve the throughput. However, the assignment of channels to radios in a multi-radio mesh network is a challenging task. In this paper, we propose a channel assignment algorithm, TICA (Topology-controlled...
Seamless handoff support is an essential issue to ensure continuous communications in wireless mesh networks (WMNs). Due to the existence of multi-hop wireless links, traditional handoff schemes designed for single-hop wireless access networks can hardly guarantee the low handoff latency requirement in WMNs. Existing solutions on reducing the handoff delay in WMNs ignore one important factor for the...
The inefficiency of legacy transmission control protocol (TCP) over wired/wireless networks inspired numerous research results in recent decade. To design a congestion control protocol that can achieve strong stability, fairness, fast convergence and high-utilization in hybrid networks, we propose AcceleRate tRansmission towards Optimal Window size TCP for Wireless networks (ARROW-WTCP) by providing...
We describe a methodology that incorporates the impact of control information transfer into MAC protocol optimization. We apply this methodology to the problem of a synchronous broadcast MAC channel, to generate the optimal protocol when the objective function is the average network throughput per slot. We describe a recursive procedure for the symbolic generation of the optimization program for any...
In this paper, we investigate the capacity of wireless hybrid networks, in which a wired network of base stations is used to support long-range communications between wireless nodes. We introduce the multiple access technique by allowing more than one source node to transmit simultaneously and utilizing successive interference cancellation to decode information at the destination node. Our results...
This article presents a new MAC layer protocol for IEEE 802.11 EDCA-based ad-hoc networks with hidden nodes. The key idea of the proposed solution is based on an intelligent two-step reservation procedure which is combined with the advantages of EDCA service differentiation. The new protocol achieves significant performance improvement for high priority traffic (e.g., Voice) in terms of fairness,...
The IEEE 802.11 standard statically channelizes the wide spectrum into smaller channels of equal width, and classically, each access point is assigned one of these channels to operate on. While an intelligent channel assignment for interfering APs can provide better network performance than just any arbitrary channel assignment, still recent work shows that even far better performance can be achieved...
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