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As one of the most widely implemented standards for wireless networks, IEEE 802.15.4 defines physical and MAC specifications for low data rate wireless personal area networks (WPANs). To accurately analyze the performance of slotted CSMA/CA (SCSMA) algorithms for saturated uplink traffic with acknowledgement (ACK) and non-ACK modes, we adopt an embedded Markov chain based model in the MAC layer of...
This paper presents a proposed measurement method utilizing the reverberation chamber to measure MAC layer throughput for LTE enabled wireless devices. By using the reverberation chamber a statistically isotropic environment is produced, which is a suitable reference environment for terminal antenna testing.
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...
Contention-based protocols for Medium Access Control (MAC) in Vehicular Ad-Hoc Networks (VANET) are currently under development in several standardization organizations. The availability and maturity of the IEEE 802.11 technology makes it the first choice for the future vehicle-to-vehicle communications. At the same time, safety applications in a vehicular environment are expected to intensively use...
The technology of flow-based QoS control on wireless LANs is receiving a lot of attention. There are several QoS technologies that can provide bandwidth guarantees by using TCP congestion control (QoS-TCP) and MAC control (QoS-MAC). Unfortunately, since QoS-TCP runs on the end terminal, it is possible that QoS-TCP will attempt to guarantee bandwidth without the permission of the network administrator...
We propose an efficient MAC protocol for OFDMA PONs that eliminates the synchronization requirement of ONUs and also exploits the statistical multiplexing gain among traffic of all ONUs for high performances in throughput and delay.
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...
In this paper, an efficient procedure for collision resolution in slotted ALOHA MIMO systems is proposed. We have proved in a previous work that packet collision resolution with spatial successive interference cancellation (SSIC) is a promising approach to improve the performance of slotted ALOHA protocol, when the colliding users' powers are different. However, it is not efficient for very close...
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...
A new cross-layer design taking advantage of OFDMA in ad hoc networks is presented. OFDMA technology is exploited at the physical layer to improve data rate through multiuser diversity and to enhance network throughput by enabling multiple concurrent transmissions over orthogonal subchannels, each consisting of a group of tones. A new tone-assignment algorithm is presented that takes advantage of...
The performance of a cross-layer (physical and MAC) design for multiple-input multiple-output (MIMO) system that maximizes the throughput of ad-hoc networks by selecting the optimum antenna combination is investigated. This cross-layer design is shown to improve the overall network performance relative to the case with no antenna selection. To further improve the overall network throughput, we minimize...
In recent years, the millimeter wave (mmWave) technology has gained considerable interest due to the huge unlicensed bandwidth (i.e., up to 7GHz) available in the 60GHz band in most part of world. In this paper, we investigate the problem of medium access control (MAC) in mmWave wireless networks, within which directional antennas are used to combat the high path loss incurred in the 60GHz band. We...
In this paper, we apply a discrete-time Markov Chain model to analyse the performance of IEEE 802.15.4 MAC Protocol with acknowledgement (ACK) frame transmission under unsaturated traffic conditions. We evaluate the system performance in terms of aggregate throughput and average power consumption of a node. Analytical results are substantiated through ns2 simulations. The effects of frame arriving...
Recent advances in high-speed wireless LANs with physical layer (PHY) rates reaching 600Mbps make them ideal for multimedia applications. It has been shown that efficiency at medium access control (MAC) layer decreases with increasing the PHY rate. To achieve high efficiency, few researches have tried to use aggregation in which few packets are concatenated into a larger frame. The resultant frame...
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...
Safety and non safety related VANET messages have localized spatial scope and limited time relevance. A MAC protocol must ensure timely delivery of such messages with high reliability over a shared wireless medium. The Vehicles moving on the road form a fluid strait jacketed topology. In this paper, an RSU centric channel allocation protocol has been proposed to minimize channel allocation time and...
This paper proposes a medium access control (MAC) protocol with network coding on relay nodes for contention-based multihop wireless relay networks. The proposed protocol is called coded packet priority access (CPPA) protocol in which coded packets have higher transmission opportunity than non-coded native packets at relay nodes. In this paper, the performance of coded packet immediate access (CPIA)...
Wireless sensor networks (WSN) are being widely deployed and used in sensing, collecting, and disseminating data for various applications in the environmental, industrial, and military sectors. The primary concern in WSNs lies in minimizing the communication between sensor nodes while achieving the desired network operation; thus extending the life time of sensor nodes. In this paper we present an...
In this paper, we study the multi-channel exposed terminal problem in multi-hop wireless networks. We first explain how the multi-channel exposed terminal problem occurs. We then propose a multi-channel MAC protocol, called multi-channel MAC with hopping reservation (MMAC-HR), to resolve the multi-channel exposed terminal problem. The proposed MMAC-HR protocol has the following features: 1) it does...
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