摘要 :
In this work, we carried out the performance analysis of Optimized Medium Access Control (MAC) Protocol for the wireless sensor network. This MAC protocol solves the energy inefficiency taking nodes latency into consideration base...
展开
In this work, we carried out the performance analysis of Optimized Medium Access Control (MAC) Protocol for the wireless sensor network. This MAC protocol solves the energy inefficiency taking nodes latency into consideration based on the network traffic. It achieves high-energy efficiency under wide range of traffic loads and is able to adjust itself to improve the delay performance when the network traffic load is high.
收起
摘要 :
A simple distributed Medium Access Control (MAC) protocol for cognitive wireless networks is proposed. It is assumed that the network is slotted, the spectrum is divided into a number of channels, and the primary network statistic...
展开
A simple distributed Medium Access Control (MAC) protocol for cognitive wireless networks is proposed. It is assumed that the network is slotted, the spectrum is divided into a number of channels, and the primary network statistical aggregate traffic model on each channel is given by independent Bernoulli random variables. The objective of the cognitive MAC is to maximize the exploitation of the channels idle time slots. The cognitive users can achieve this aim by appropriate hopping between the channels at each decision stage. The proposed protocol is based on the rule of least failures that is deployed by each user independently. Using this rule, at each decision stage, a channel with the least number of recorded collisions with the primary and other cognitive users is selected for exploitation. The performance of the proposed protocol for multiple cognitive users is investigated analytically and verified by simulation. It is shown that as the number of users increases the user decision under this protocol comes close to the optimum decision to maximize its own utilization. In addition, to improve opportunity utilization in the case of a large number of cognitive users, an extension to the proposed MAC protocol is presented and evaluated by simulation.
收起
摘要 :
Most existing multichannel medium access control (MAC) protocols have at least one of the following four performance bottlenecks: 1) global synchronization among users; 2) dedicated control channel for signaling exchange; 3) dedic...
展开
Most existing multichannel medium access control (MAC) protocols have at least one of the following four performance bottlenecks: 1) global synchronization among users; 2) dedicated control channel for signaling exchange; 3) dedicated control phase for signaling exchange; and 4) complete knowledge of all users' channel selection strategies. In this paper, we first design a hopping sequence by combining multiple difference sets to ensure a high rendezvous probability of users over multiple channels. Applying the hopping sequence to all users, we then propose a difference-set-based multichannel MAC (DSMMAC) protocol to overcome the performance bottlenecks. Because all users use the same sequence for frequency hopping and channel access, significant signaling overheads can be reduced. The proposed protocol achieves high system throughput and low access delay without the need for global synchronization or a dedicated control channel/phase. Our analytical and simulation results show that the proposed DSMMAC protocol can achieve up to a 100% improvement in system throughput and a 150% reduction in channel access delay compared with an existing multichannel MAC protocol.
收起
摘要 :
Efficient radio spectrum utilization and low energy consumption in mobile devices are essential in developing next generation wireless networks. This paper presents a new medium access control (MAC) mechanism to enhance spectrum ...
展开
Efficient radio spectrum utilization and low energy consumption in mobile devices are essential in developing next generation wireless networks. This paper presents a new medium access control (MAC) mechanism to enhance spectrum efficiency and reduce energy consumption in a wireless ad hoc network. A set of coordinator nodes, distributed in the network area, periodically schedule contention-free time slots for all data transmissions/receptions in the network, based on transmission requests from source nodes. Adjacent coordinators exchange scheduling information to effectively increase spatial spectrum reuse and avoid transmission collisions. Moreover, the proposed MAC scheme allows a node to put its radio interface into a sleep mode when it is not transmitting/receiving a packet, in order to reduce energy consumption. Simulation results demonstrate that the proposed scheme achieves substantially higher throughput and has significantly lower energy consumption in comparison with existing schemes.
收起
摘要 :
We propose a modeling framework composed of a Markov chain and the related coupling equations to evaluate the performance of unslotted IEEE 802.15.4 wireless sensor networks based on CSMA/CA medium access control. Different from t...
展开
We propose a modeling framework composed of a Markov chain and the related coupling equations to evaluate the performance of unslotted IEEE 802.15.4 wireless sensor networks based on CSMA/CA medium access control. Different from the related literature, the proposed model is able to capture heterogeneous classes of nodes with class-specific traffic generation rate and includes a more refined calculation of the probability of finding the channel busy during the carrier sensing process. The proposed model is used to derive class-specific performance figures including the probability of a successful transmission and the average delay for a successful/unsuccessful transmission.
收起
摘要 :
Worldwide interoperability for microwave access (WiMAX) based wireless metropolitan area networks have recently received wide attention as they support high data rates with great quality of service (QoS) capabilities. In order to ...
展开
Worldwide interoperability for microwave access (WiMAX) based wireless metropolitan area networks have recently received wide attention as they support high data rates with great quality of service (QoS) capabilities. In order to support QoS, bandwidth request (BW-REQ) mechanisms are suggested in the WiMAX standard for resource reservation. In this letter we propose a simple and accurate analytical model for the performance analysis of contention-based bandwidth request mechanisms. The accuracy of this model is verified with simulation results.
收起
摘要 :
In this paper, we propose a novel medium access control (MAC) protocol, called SYN-MAC (for SYNchronized MAC), based on a binary countdown approach tailored for wireless networks. SYN-MAC has several attractive features such as si...
展开
In this paper, we propose a novel medium access control (MAC) protocol, called SYN-MAC (for SYNchronized MAC), based on a binary countdown approach tailored for wireless networks. SYN-MAC has several attractive features such as simplicity, robustness, high efficiency, fairness, and quality of service capability. We evaluate SYN-MAC in terms of collision probability, system throughput, and packet delay, via both analysis and simulation. Our results show that, with properly chosen parameters, SYN-MAC can achieve a very low collision probability, packet delay tolerance, and extremely high channel efficiency (of > 90%) under a wide range of traffic load. As a result, SYN-MAC may serve as an alternative to IEEE 802.11 for the wireless stations in synchronized networks.
收起
摘要 :
Packet-based optical access ring is becoming a promising solution in metropolitan networks. Its performance depends mainly on how optical resource sharing takes place among the different competing access nodes. This network archit...
展开
Packet-based optical access ring is becoming a promising solution in metropolitan networks. Its performance depends mainly on how optical resource sharing takes place among the different competing access nodes. This network architecture has mostly been explored with regard to synchronous transmission, i.e., slotted wavelength-division multiplexing (WDM) ring. However, in this paper, we focus on the performance of asynchronous transmission-based networks with variable packet sizes. Analytical models are presented in an attempt to provide explicit formulas that express the mean access delay of each node of the bus-based optical access network. We prove that in such a network, fairness problems are likely to arise between upstream and downstream nodes sharing a common data channel. Furthermore, we show that sharing the channel's available bandwidth fairly but arbitrarily between access nodes, as in slotted WDM rings, does not resolve the fairness problem in asynchronous system. In this regard, we exhibit the inherent limitations of the token bucket access rate-based algorithm once applied to asynchronous transmission bus-based networks. To alleviate the aforementioned problem, we device a new strategy called traffic control architecture using remote descriptors. The proposed solution is based on a preventive mechanism to grant access to the shared resource. As illustrated in this paper, the proposed solution alleviates the performance degradation and the resource underutilization, while achieving fairness among bus nodes.
收起
摘要 :
In this paper, we propose Period-Controlled Medium Access Control (PC-MAC), which can operate in pseudo-TDMA manner and achieves high throughput and fairness in simple networks. PC-MAC works like CSMA/CA initially and becomes a ps...
展开
In this paper, we propose Period-Controlled Medium Access Control (PC-MAC), which can operate in pseudo-TDMA manner and achieves high throughput and fairness in simple networks. PC-MAC works like CSMA/CA initially and becomes a pseudo-TDMA scheme in a few seconds due to the periodic backoff mechanism along with the contention control that tries to maintain the number of idle slots to an optimal level. Simulation results show 10%–50% higher throughput than distributed coordination function (DCF), depending on the number of nodes, while maintaining nearly perfect fairness. Furthermore, we also show how PC-MAC can successfully be applied to complex networks.
收起
摘要 :
In this letter we introduce a connection admission control (CAC) mechanism for IEEE 802.16 broadband wireless access Standard. Our scheme is based on bandwidth reservation concept and has been developed considering the problem of ...
展开
In this letter we introduce a connection admission control (CAC) mechanism for IEEE 802.16 broadband wireless access Standard. Our scheme is based on bandwidth reservation concept and has been developed considering the problem of "busy hour" in communications traffic variation during a typical day. The proposed solution, which is compatible to the IEEE 802.16 Standard, provides higher priority to VoIP calls compared to other types of traffic in the network. The performance of the proposed scheme is evaluated by means of computer simulations, while an analytical solution is provided as well.
收起
