Traffic-aware channelization medium access control for wireless ad hoc networks

Traditional IEEE 802.11-based networks use only a single channel to ensure connectivity; however, multi-channel capability is available to provide higher network throughput by allowing simultaneous multiple transmissions that do not interfere with each other. The use of multiple channels raises several new challenges: mainly finding the receiver, scheduling the next transmission, balancing the load among channels, and dealing with multi-channel hidden terminals. This paper proposes a novel and efficient, asynchronous multi-channel medium-access control (MAC) protocol using a single transceiver. The key technique is that the proposed protocol separates searching and scheduling processes where searching users switch channels faster than regular users. Simulation results indicate that the proposed protocol achieves up to 14.10 Mbps network throughput, whereas the IEEE 802.11 MAC protocol, with a single channel, provides only 4.35 Mbps in the best case when three orthogonal channels with an 11- Mbps data rate are available

This paper proposes a novel multi-channel medium access control (MAC) that is based on CSMA/CA mechanism. The objective of this research is to evaluate the possibility of increasing network capacity and addressing collision problem of wireless sensor network comprising of low spec physical hardware. The proposed protocol can be implemented into wireless sensor network platform i.e. MICAz, Tmote-Sky without any additional hardware or firmware. Experiment results show that the proposed protocol can effectively improve the network performance compared with traditional single channel MAC.

Cognitive Radio (CR) exploits underutilized licensed spectrums to improve its bandwidth availability. Using CR technology, a node is able to adapt its transmission and reception radio parameters including channel frequency dynamically according to local spectrum availability. For channel access between wireless nodes, a cognitive Medium Access Control (MAC) protocol is necessary to coordinate the CRs. Multi-channel MAC protocol extensions have been proposed in IEEE802.11 to enable a node to operate in multiple channels in order to improve network-wide throughput. These multi-channel MAC protocols have several functions that can be leveraged by cognitive MAC protocols due to their similarities in certain aspects, though the CR has an additional requirement to cope with the existence of licensed users that have higher authority over the channels. Current research in cognitive MAC protocols assumes the availability of a common control channel at all times, which is an approach in the multi-channel MAC protocols. This approach has certain hardware requirements that may not be readily available at CR nodes. Hence, other approached may be necessary. In this paper, various types of multi-channel MAC protocols are reviewed, followed by discussion of their merits and demerits in multi-channel environments. The purpose is to show the additional functionalities and challenges that each multi-channel MAC protocol has to offer and address in order to operate in multihop CR networks. By providing discussion on possible technology leverage from multi-channel to cognitive MAC protocols, we aim to establish a foundation for further research and discussion.

Since cognitive wireless network (CRN) has the characteristic of secondary use, it can enable the device to dynamically access available spectrum without interference to primary users (PUs), which can effectively alleviate contradiction between the lack of spectrum resources and the growing demand for wireless access. However, Medium Access Control (MAC) protocol as CRN core components, can achieve competition access of the licensed spectrum and coordination control, which will maximize spectrum utilization efficiency and network throughput. The contribution of this survey is threefold. First, we analyze the characteristics of the existed multi- channel MAC protocol in CRN; Second, according to the different ways of spectrum access in CRNs, the multi-channel MAC protocols are classified into time-slotted based MAC protocol, control channel based MAC protocol and hybrid MAC protocol, and the paper emphatically analyzed the advantages and disadvantages of these multi-channel MAC protocols; Finally, the paper explores the difficulties and the challenges of multi-channel MAC protocols design in cognitive wireless network.

The so-called Internet of Things (IoT) aims at connecting every single object to the Internet with the purpose to automate every aspect of daily life. The IoT relies heavily on wireless low-power and lossy networks (LLNs) that collect information from the physical world and send the measurements to data aggregation and processing nodes. Most LLNs operate in the non-licensed industrial, scientific, and medical radio band, which is shared by a considerable number of systems. Coexisting wireless systems cause interference to each other, limiting their achievable performance. Multichannel communications enable frequency diversity, which in turn provides robustness against interference as well as increased network capacity. There is a considerable interest in multichannel medium access control (MAC) protocols for LLNs, including an evolving standard for the MAC layer of LLNs. In this paper, we review the latest advances in the topic and introduce a new classification framework for multichannel MAC protocols for LLNs. While our framework builds on previous review and classification studies, it adds aspects of a MAC protocol that reflect its interactions with the surrounding network stack. Seeing the resource constraints of the LLN devices, the study of such interactions—which is missing in prior classification efforts—can be the key for improving future designs. Relevant protocols published since 2006 are discussed and classified using the presented framework, including the recent multichannel MAC protocols for LLNs, such as the latest version of the IEEE 802.15.4 standard for time slotted channel hopping.

A cooperative CDMA-based multi-channel MAC protocol for mobile ad hoc networks

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.

Multichannel media access control (MAC) protocols can increase wireless network capacities. The rendezvous problem is the most frequently encountered challenge in developing multichannel MAC protocols. Some studies have assumed that each device is equipped with one additional antenna; however, this increases the hardware cost. Other studies have divided the timeline of each channel into several beacon intervals. All stations are awake simultaneously on a predefined channel to enable rendezvous opportunities; however, this leads to low bandwidth utilization. This paper presents an efficient staggered multichannel MAC protocol (SMC-MAC) for ad hoc networks. By using a single antenna, the proposed SMC-MAC applies a staggered channel model with a home channel concept for exploiting multichannel bandwidth resources. Performance results reveal that the proposed SMC-MAC outperforms existing multichannel MAC protocols in terms of network throughput, control packet collision ratio, packet delay time, packet discarding, packet loss ratio, control overhead, and robustness.

Multichannel Medium Access Control (MAC) protocols for IoT can potentially improve network performance. Therefore, a considerable number of such protocols have been proposed in the last decade, ranging from slotted synchronous to contention-based asynchronous multichannel protocols. In this paper two of the most representative multichannel MAC layer protocols are compared: Time-Slotted Channel Hopping (TSCH) using the Orchestra scheduling algorithm, and Energy-Efficient Multichannel MAC (EM-MAC). The performance of these protocols is assessed under different traffic loads and node densities using the standard IPv6 Routing Protocol for Low-Power and Lossy Networks (LLNs), i.e. RPL. The results show the cross-layer interaction between the RPL protocol and the multichannel MAC schemes under study. Moreover, it can be generally appreciated that TSCH/Orchestra performs better in terms of Packet Delivery Ratio (PDR) whereas EM-MAC exhibits lower power consumption. These characteristics reveal the suitability of these protocols for different IoT applications.

Medium access control (MAC) protocols have been studied under different contexts for several years now. In all these MAC protocols, nodes make independent decisions on when to transmit a packet and when to back-off from transmission. In this paper, we introduce the notion of node cooperation into MAC protocols. Cooperation adds a new degree of freedom which has not been explored before. Specifically we study the design of cooperative MAC protocols in an environment where each node is equipped with a single transceiver and has multiple channels to choose from. Nodes cooperate by helping each other select a free channel to use. We show that this simple idea of cooperation has several qualitative and quantitative advantages. Our cooperative asynchronous multi-channel MAC protocol (CAM-MAC) is extremely simple to implement and, unlike other multi-channel MAC protocols, is naturally asynchronous. We conduct extensive simulation experiments. We first compare CAM-MAC with IEEE 802.11b and a version of CAM-MAC with the cooperation element removed. We use this to show the value of cooperation. Our results show significant improvement in terms of number of collisions and throughput for CAM-MAC. We also compare our protocol with MMAC and SSCH and show that CAM-MAC significantly outperforms both of them.

Designing QoS-aware medium access control (MAC) scheme is a challenging issue in vehicular ad hoc networks. Proportional fairness and bandwidth utilization are among the significant requirements that should be taken into account by a MAC scheme. In this paper, a bandwidth-efficient and fair multichannel MAC protocol is proposed to address these two requirements, specifically in vehicle-to-vehicle communications. The proposed scheme is based on clustering of vehicles and exploits time division multiple access (TDMA) method alongside the carrier sense multiple access with collision avoidance mechanism to allocate DSRC-based resources in a different manner from IEEE 802.11p/IEEE 1609.4 protocols. It divides each channel into aligned dynamic-sized time frames. In each time frame, in a fully TDMA-based period, transmission opportunities are assigned to vehicles letting them have dedicated transmissions on the service and control channels. The maximum number of transmission opportunities per each frame is determined by the cluster head (CH) based on a defined optimization problem which aims at maximizing both proportional fairness and bandwidth utilization. Furthermore, the bandwidth utilization is assumed to be enhanced more through reallocation of unused transmission opportunities in each time frame, using a proposed reallocation algorithm. The proposed MAC protocol is treated as a lightweight scheme such that various types of unicast, multicast and broadcast communications are possible within the cluster without involving the CH. Evaluation results show that the proposed scheme has more than 90 % achievement in terms of proportional fairness and bandwidth utilization simultaneously, and in this case, has a considerable superiority over TC-MAC. In addition, using the proposed scheme, the satisfaction level of vehicles is preserved appropriately.

Communication in the underwater wireless sensor networks (UWSNs) faces many challenges due to the acoustic wave characteristics. Acoustic wave has very limited bandwidth, long propagation delay, high bit error rate (BER), and unreliable communication compared to the radio wave. Therefore, media access control (MAC) protocols proposed in terrestrial wireless sensor networks (TWSNs) cannot be implemented underwater as TWSNs rely on radio waves and enables multiple transmissions at a time without causing a collision. Besides, underwater nodes operate in a half-duplex mode and only allows one transmission at a time. Designing an efficient MAC protocol for underwater time-sensitive applications, such as the oil/gas pipeline and climate change prediction applications is necessary. While each application has its own requirements, the software-based approach promises great enhancements to meet more than one application's requirements. The software-based approach allows us to reconfigure the variables through a software without additional hardware requirements. To address the above issues, this paper proposes a software-based MAC protocol that utilizes optical and acoustic wave for communication and allows multiple transmissions at a time in different directions. This study aims to maximize throughput, packet delivery ratio (PDR), network utilization while minimizing latency.

Power efficient ultra-wideband based wireless communication for wireless body area network applications

Provisioning of high throughput in wireless mesh networks (WMNs) is a challenging issue for medium access control (MAC) protocol. This is due to not only some difficult problems present in such networks such as the hidden and exposed terminal problems but also the fact that a WMN is often used as a backbone network requiring more reliable and efficient performance. Note that multi-channel based MAC protocols were proposed in the literature to handle the hidden and exposed terminal problems in multi-hop wireless ad hoc networks. Here this approach is advocated for WMNs since many literature studies show that it can much outperform the singlechannel based MAC protocols but at the expense of increased implementation complexity, which however should be acceptable in backbone WMNs. However, most existing multi-channel based MAC protocols use dedicated control channels (DCC). DCCs not only causes channel wastage but also may become a performance bottlenecks, both of which are undesirable for WMNs. In this paper, we discuss a new MAC scheme which does not use any DCCs and only requires one transceiver per node for the implementation. The simulation studies show that this scheme can outperform the one using DCCs especially in the case of heavy traffic loads.

In this paper, we propose and investigate an efficient multichannel Medium Access Control (MAC) protocol for Cognitive Radio Ad Hoc Networks (CRAHNs). The proposed protocol supports Secondary Users' (SUs) dynamic utilization of the licensed channel of Primary Users (PUs) to enable the SUs' performance of a multichannel data transmission simultaneously and without interfering with each other. The proposed protocol can be cooperative or non-cooperative. The cooperative protocol scheme enables a SU to sense PU's presence independently in a multichannel architecture and then broadcasts the report to its neighbors in a proactive fashion. The performance of the cooperative and non-cooperative protocol schemes is simulated and compared. The performance demonstration focuses not only on the SU performance but also on the PU's performance with an Ad hoc On-demand Distance Vector (AODV) routing protocol. The simulation results show that the proposed protocol enhances the network utilizations in general and that the cooperative scheme significantly enhances the Packet Delivery Ratio (PDR) and decreases the end-to-end delay of SUs with high traffic PU connections.