SAM-MAC

Mobile Ad-hoc Networks (MANETs) are special kind of wireless networks with no centralized control. They are ideal candidate for several real world applications where network need to be established on the fly e.g. disaster hit areas, hospitals, military surveillance etc. Researchers have been actively working in this area for a decade or so to make this concept a reality. MANETs differ from conventional fixed networks and therefore pose several challenges to the researchers working in the area. Among many others, access to shared medium is the major problem in MANETs. In such networks MAC layer protocol plays an important role in efficient utilization of shared media in distributed fashion. At the MAC layer we have three contradicting requirements, Maximize channel utilization, Minimize Control overhead and Fairness. Multi-Channel MAC protocols are considered is the most suitable solution to achieve the desired objectives but channel assignment and reservation in a distributed fashion is still a big challenge. In this paper, we have proposed a Multi- Channel scheme to address the problem of channel assignment the proposed scheme is Nodeid based. The proposed Scheme has been compared with conventional single channel scheme using ns-2 simulation and results shows that the proposed technique gives better performance. Keywords- BEB algorithm, Clear to send, Control channels, Dedicated Channels, MAC, Overhead, and request to send.

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.

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.

In multi-channel WLANs, the MAC protocol allocates a channel to each transmission pair while avoiding interference. In the channel allocation phase, if the MAC protocol allocates one channel iteratively to multiple narrowly spaced transmission pairs, both channel utilization and network throughput can be improved. However, such an approach leads to traffic overload; thus, if a transmission takes place over a transmission channel, the number of terminals that can receive the transmission decreases. B-MAC, a multi-channel MAC protocol designed for broadcast, starts a new broadcast transmission after waiting for a certain period of time; however, this waiting time increases the transmission overhead and degrades channel utilization. In this paper, we propose CA-BMAC, a new multi-channel MAC protocol that reduces the waiting time associated with B-MAC, and thus, the transmission overhead. Performance evaluations of the proposed protocol clarify its advantages over B-MAC.

In recent years, multi-channel MACs have attracted considerable attention in wireless networking research. Motivation for research into multi-channel MACs is their potential to increase the capacity of wireless ad hoc networks by exploiting multiple orthogonal frequency bands. This potential has been confirmed by several simulation studies that reported promising results for multi-channel MACs. However, the analytical performance of these protocols is not well understood. In this work, we present an analytical framework for modeling the performance multi-channel MACs in multi-hop networks. We employ our framework to investigate the performance of three representative multi channel MACs: Asynchronous Multichannel Coordination Protocol (AMCP), Multi-Channel MAC (MMAC), and Slotted Seeded Channel Hopping (SSCH). The important findings of our analysis are: (1) SSCH outperforms AMCP and MMAC in both 802.11b and 802.11a scenario, (2) AMCP performs worse than MMAC in 802.11b because the overhead of AMCP's control channel is higher than that of MMAC's control interval, and (3) the overhead of AMCP's control channel becomes negligible in an 802.11a scenario and is outweighed by that of MMAC's control interval. For this reason, AMCP delivers better performance than MMAC in 802.11a scenario.

In mobile ad-hoc network, some multi-channel MAC protocols utilize multiple channels to reduce the collision of wireless transmission and thus get high throughput. These multi-channel MAC protocols aim at improving the performance of unicast communication, and multicast data are generally transmitted as broadcast. So multicast cannot benefit from the multi-channel technique. This paper proposes a multi-channel media access control protocol for multicast (MCMAC) which uses multi-channel techniques to improve multicast performance. To improve the reliability of MAC layer, we extended a reliable multi-channel MAC protocol for multicast (RMCMAC) based on MCMAC. Taking ODMRP [S.-J. Lee et al., 2000] as an example of multicast routing protocols, we evaluate the multicast performance of MCMAC and RMCMAC for ad hoc networks via detailed simulation.

We address the problem of improving the throughput and security of multi-channel MAC (MMAC) protocols. We design a protocol called FD-MMAC that exploits recent advances in full duplex (FD) communications to coordinate channel access in a distributed manner. Compared with prior MMAC designs, our protocol eliminates the use of dedicated in-band or out-of-band control channels for resolving contention, discovering the resident channel of destinations, and performing load balancing. The elimination of the control channel improves spectral efficiency and mitigates denial-of-service attacks that specifically target the exchange of control information. Moreover, FD-MMAC enables the operation of multi-channel exposed terminals. To achieve these goals, we integrate an advanced suite of PHY-layer techniques, including self interference suppression, error vector magnitude and received power measurements, and signal correlation. We validate the proposed PHY-layer techniques on the NI USRP testbed. Furthermore, we theoretically analyze the throughput performance of FD-MMAC and verify our analysis via packet level simulations. Our results show that FD-MMAC achieves significantly higher throughput compared with prior art. Finally, we analyze the resilience of FD-MMAC to reactive jamming attacks.

IEEE 802.11p is a communication protocol which is extended by IEEE 802.11 standard, mainly used in Vehicular Ad-Hoc Networks (VANETs). VANETs generally include the Service Channel (SCH) and Control Channel (CCH). In the traditional 802.11p protocol, the length ratio between CCH and SCHs is fixed. This paper presents a variable SCH interval(VSI) multichannel medium access control (MAC) scheme under the non-saturated channel. Under this scheme, we can control the length of CCH interval and SCH interval. This paper uses three-dimensional Markov chain model to calculate the delay of WAVE service announcement (WSA) frame. We propose a VSI MAC calculation model under unsaturated condition to achieve the maximum throughput. The simulation results indicate that the proposed scheme can help VANETs increase the unsaturated throughput of SCHs and lower the transmission delay of data frames obviously.

In this paper we address the control channel assignment problem in a cognitive radio based wireless network, namely the CogMesh. Such a network is featured by the dynamic spectrum sharing of the secondary users coexisting with the primary users. The opportunistic nature of the spectrum utilization among the secondary users makes a global control channel infeasible. The self-coordination of the network, hence, becomes a challenge task. Considering the fact that common channels may temporarily exist among a local group of secondary users, we propose an adaptive approach that selects local common control channels independently by each secondary user according to the qualities of the detected spectrum holes and the choices of its neighbors. To achieve this, a swarm intelligence-based algorithm is used to facilitate the common control channel selection. The idea is to use HELLO messages periodically broadcasted by neighbors as the pheromone to rank the common channels so as to expedite the channel selection process. The algorithm is completely distributed and therefore scalable. Moreover, it is simple, flexible, adaptive, and well balanced on the exploitation and exploration of the radio resources. The behaviors and performance of the proposed algorithm are verified by simulation.

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.

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.

In this paper, a multi-channel preamble sampling MAC protocol, MCPS, especially designed for wireless sensor networks, is proposed and thoroughly evaluated. MCPS is a low power MAC protocol operating on multichannel using carrier sensing for collision avoidance. Specifically, MCPS exploits all the non-overlapping channels provided by IEEE 802.15.4 physical layer. Basically, MCPS uses one dedicated common control channel to wakeup an intended receiver using a preamble sampling technique. However, data transmission takes place in a dedicated data channel. In fact, MCPS allows each sensor node to dynamically adjust its transmission power when sending strobed preamble or periodically generated data. Indeed, for each possible distance separating a pair of communicating nodes, MCPS adapts the appropriate transmission power and selects the appropriate data channel. By using multiple channels, MCPS allows multiple simultaneous communications reducing hence the end-to-end delay and improving the throughput. MCPS has been implemented using OMNET++ simulator under INET framework, on top of the IEEE 802.15.4 physical layer, which it was improved to support the multi channel communication. Simulation results show that MCPS can greatly improve the network performance especially in terms of throughput and end-to-end delay.

We propose a cross-layer based multi-channel Medium Access Control (MAC) protocol to maximize the utilization of the leftover spectrum of primary user channels in cognitive radio networks. This protocol integrates the spectrum sensing at Physical layer and the packet scheduling at the MAC layer for mobile ad-hoc networks. With a TDMA-based control channel, we have a scheme to handle collision. Moreover, our scheme is suitable for heterogeneous network with different device capabilities. We formulate the channel allocation problem as a constrained optimization problem and propose strategies to handle channel allocation based on graph theoretic principles, specifically using Weighted Bipartite Graph Matching technique. We name our proposed modeling as Weighted Bipartite Multi-Vertex Matching (WBMM) and describes three different schemes based on this model. We conduct extensive simulation studies to analyze and compare the performance of the proposed strategies.

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

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.