CA-BMAC: A collision avoidance multi-channel broadcast MAC protocol with a mechanism for reducing transmission overhead

In high diversity node situation, single-channel MAC protocols suffer from many collisions. To solve this problem, the research of multichannel MAC protocol has become a hotspot. And the cyclic quorum-based multichannel (CQM) MAC protocol outperformed others owing to its high frequency utilization. In addition, it can avoid the bottleneck that others suffered from and can be easily realized with only one transceiver. To obtain the accurate performance of CQM MAC protocol, a Markov chain model, which combines the channel hopping strategy of CQM protocol and IEEE 802.11 distributed coordination function (DCF), is proposed. The metrics (throughput and average packet transmission delay) are calculated in performance analysis, with respect to node number, packet rate, channel slot length and channel number. The results of numerical analysis show that the optimal performance of CQM protocol can be obtained in saturation bound situation. And then we obtain the saturation bound of CQM system by bird swarm algorithm (BSA). Finally, the Markov chain model and saturation bound are verified by Qualnet platform. And the simulation results show that the analytic and simulation results match very well.

Recent research has demonstrated the feasibility of full-duplex (FD) communication over the same frequency channel. This capability, facilitated by new self-interference suppression techniques, has great potential to increase the network capacity. However, exploiting FD in the context of a multi-user, multi-channel network is still being debated. This paper focuses on the channel access issue and presents a novel multi-channel MAC (MMAC) protocol for wireless ad hoc networks with FD and orthogonal frequency-division multiple access (OFDMA) capabilities. Through these capabilities, a node can simultaneously carry out multiple transmissions and/or receptions over the same or different channels. In our MMAC protocol, a pair of nodes negotiate data channels, transmission rates, transmission powers, and transmission modes (e.g., FD or half-duplex) in a distributed manner so that their spectral usages are minimized while their rate demands are still met. Extensive ns3 simulations show that our MMAC protocol increases the end-to-end network goodput by up to 150% and decreases the end-to-end delay by up to 300% compared with an OFDMA-based protocol without FD.

Recently, many MAC protocols have been proposed for effective communication in the single transceiver multi-channel environment. In these MAC protocols, however, the multi-channel hidden terminal problem degrades the throughput of the communication systems. In order to mitigate the effects of the multi-channel hidden terminals, two MAC protocols have been proposed: cooperative asynchronous multi-channel MAC (CAM-MAC), where neighbouring terminals inform a sender of its bad channel selection and virtual topology MAC (VT-MAC), where redundant channel usage information is reduced by considering the network topology. However, these MAC protocols mainly focus on avoiding bad channel selections by the sender, and not on increasing good channel selections (concurrent transmissions). Therefore, in this paper, to further improve throughput performance by concurrent transmissions, we propose new multi-channel MAC protocols in which neighbour terminals of a sender recommend a better transmission channel prior to the data transmission. The performance evaluations verify that the proposed MAC protocol effectively improves the throughput performance when compared to existing MAC protocols, especially when the channel negotiation process induces the larger overhead at the short data transmission.

The use of multi-channel MAC protocols for mobile ad hoc networks has been seen as a very potent method of improving the throughput capacity of such networks. In recent past, a number of multi-channel MAC protocols have been proposed for mobile ad hoc networks that have increased the overall network throughput by quite some margin compared to their single channel counterparts. However, there are still many issues with these protocols that need to be resolved. Clock synchronization is one of the major overhead in a majority of the proposed multi-channel MAC protocols. In this paper we propose a new asynchronous multi-channel MAC protocol that does not require clock synchronization between mobile nodes. Our proposed protocol is an asynchronous solution that uses multiple channels for data transmission. In our proposed protocol, nodes use a single base channel when the network load is considerably lower and migrates to other channels when the network load increases beyond a threshold value. Also, nodes share multi-channel cooperation messages with their neighbors to further improve throughput. We have conducted extensive simulations to compare the performance of our protocol against the traditional IEEE 802.11b single channel and MMAC protocol. Simulation results show that our proposed protocol outperforms both IEEE 802.11b and MMAC protocol.

CogMOR-MAC: A cognitive multi-channel opportunistic reservation MAC for multi-UAVs ad hoc networks

A vehicular ad hoc network (VANET) is designed to enable efficient and authentic node/infrastructure communication. The primary role of VANETs is to distribute time-sensitive safety messages (sm) regularly, which causes packet congestion and broadcast failure due to the network’s limited spectrum. For efficient and reliable delivery, the proposed paper uses a spatial hybrid division multiple access (SDMA) and time division multiple access (TDMA) over the control channel interval and hence termed a spatially distributed multichannel MAC (SDM-MAC) protocol. The frequency reuse approach is used to transfer data while efficiently utilising bandwidth, and throughput is considerably enhanced with carrier sense multiple access with collision avoidance (CSMA/CA) and with the help of TDMA. Moreover, an adaptive algorithm is proposed for an intelligent channel frame structure using this protocol to manage the highly dynamic scenario. The Markov chain defines the protocol, and the network simulator (NS2) analyses several performance metrics. Comparing the response with two existing MAC protocols, the proposed protocol reduces average latency compared to current MAC methods and improves the packet delivery ratio and throughput by an average of 26% and 28%, respectively.

The development of mobile communication services has lead to the increase the use of wireless spectrum. However, the persuasion of the overly crowded spectrum is not due to the scarcity of usable radio frequencies but to the current static spectrum management policy. This reveals many idle frequency bands in both time and space. The cognitive radio network (CRN) is a key solution to exploit the existing spectrum dynamically. In this paper, we propose a new Reactive Multi-Channel cognitive MAC protocol (RMC-MAC) that integrates a novel cooperative sensing scheme which reliably detects the presence of incumbents even if the secondary users are transmitting. Then, a recovery scheme is proposed to ensure the continuity of SU transmission and to reduce the forced termination probability. This recovery solution also shows that bandwidth utilization is higher than the one achieved by a common protocol without handoff and another buffering based protocol.

A novel multi-channel MAC protocol with directional antenna for enhancing spatial reuse and bandwidth utilization in WLANs

A number of multichannel MAC protocols have been developed earlier with the objective of maximizing energy efficiency and guaranteeing QoS requirements in wireless sensor networks. However, the trade-off between energy efficiency and QoS requirements remains an open issue. In this paper, we propose a multichannel MAC protocol so that nodes dynamically switch their interface between the channels to achieve this goal. The proposed protocol works in two phases, the advertisement (ADV) phase and data phase, which run concurrently. During the ADV phase, the nodes having data try to contend the advertisement channel to transmit the ADV packet. The nodes after receiving the acknowledgement from the receiver switch to the available free channel for the transmission of data packet. We analyze the performance of our proposed protocol through simulation. The simulation results reveal the proposed protocol performs better than the existing MAC protocols in terms of data delivery ratio, end-to-end delay and energy efficiency.

In this paper, an interference and throughput aware multi-channel MAC protocol (ITMMAC) is designed for actor-actor coordination in wireless sensor-actor networks (WSAN). Each actor consists of multiple transceivers, hence it can simultaneously transmit or sense on multiple non-interference channels. ITMMAC protocol divides the beacon interval into ad-hoc traffic indication message (ATIM) window and data transmission phase. In the ATIM window, sender negotiates the minimum interference and maximum throughput channel among the available channels with the destination. Each actor processes the channel negotiation phase in the dedicated control channel. The proposed ITMMAC protocol is simulated using NS2. The obtained simulation results are analyzed using network parameters such as average throughput and average packet delay in the network. The simulation results indicate that the proposed ITMMAC protocol performs well as compared to the existing MAC protocols.

The Cognitive Radio (CR) is a recent technology that aims at increasing the spectrum utilization under the current static spectrum management. With appropriate CR MAC protocols, the unlicensed users, also called secondary users (SUs), are able to access the unused portion of spectrum in an opportunistic way. These protocols should also provide a coordinated access between the SUs and protect the licensed users (or primary users, PUs) from the induced interference. In this paper, we propose a novel multi-channel cognitive MAC protocol based on a cooperative spectrum access among the SUs, which enhances the throughput of the cognitive radio network (CRN) subject to a SU transmit power constraint. Our proposed protocol introduces a new reactive sensing period and a novel recovery scheme to instantly detect the presence of a PU, and proposes an adaptive handoff to preserve the continuity of the SU transmission. The results of simulation show the effectiveness of our protocol. The aggregate throughput of the SUs is improved and the handoff delay is considerably reduced.

A receiver-centric multi-channel MAC protocol for wireless networks

In a smart grid environment, wireless sensor networks (WSNs) perform a significant role in supervising and taking control decisions based on the data transferred from source to destination. The work in this paper is aimed to develop a cross-layer multi-channel MAC (CMCMAC) protocol for interference mitigation between ZigBee and WiFi operating in common 2.4GHz frequency band. In this protocol, to avoid the interference between the channels, the future interference is predicted using the hidden Markov model, based on the prediction a channel with the minimum interference is selected for data transmission to enhance the network performance. The results obtained show the enriched network performance.

Using multi-channel MAC protocols in mobile ad hoc networks (MANETs) is a promising way to improve the through-put performance. Channel assignment, which directly determines the efficiency of the frequency utilization, is the critical part of multi-channel schemes. Current 802.11-like schemes of multi-channel MAC do not efficiently use the multiple channels due to the overhead caused by channel assignment. Moreover, the control channel saturation problem limits the number of channels of these previous schemes. In this paper, we propose a new scheme called SAM-MAC (Self-Adjustable Multi-channel MAC), which features with one common channel and two half-duplex transceivers for each node. A method called self-adjustment is used to reassign the channels and balance the traffic on different channels. Due to less contention in common channel and smaller channel assignment overhead, this scheme increases the throughput compared with previous approaches. Control channels are free from saturation problem and can furthermore be used for data transmission.

Ultra wide band (UWB) technology is a wireless communication technology which has a lot of characters, such as low cost and power consumption, simple structure, precise location ability, high space capability, which is suitable for ad hoc wireless network particularly. Its precise location ability has great help in designing of MAC layer of ad hoc wireless. In this paper, we design a multi-channel MAC protocol of ad hoc wireless network based on location information, mainly introduce the part of channel assignment. The main ideas of this protocol is to assign channel according to the physical location of hosts and we discuss the effect of grid size and simulation shows this protocol has better performance in reduce interference and throughput of networks than static channel assign protocol if we choose proper grid size.