Multi-channel Hidden Terminal Problem Research Articles

SFM-MAC: Multichannel MAC Protocol for Underwater Sensor Networks Based on Underwater Passive Localization Mechanisms

Yang, Q.; Dong, W.; Xu, Z., and Huang, X., 2020. SFM-MAC: Multichannel MAC protocol for underwater sensor networks based on underwater passive localization mechanisms. Journal of Coastal Research, 36(6), 1332–1342. Coconut Creek (Florida), ISSN 0749-0208.With the continuous development of ocean research in recent years, underwater acoustic sensor networks, as the extension of terrestrial wireless sensor networks (WSNs), play an increasingly important role in ocean and coastal research. To solve the problem of spatial unfairness caused by spatiotemporal uncertainty of underwater acoustic signal propagation in underwater WSNs and improve the throughput of underwater networks, this paper proposes a slotted-floor multichannel medium access control (SFM-MAC) protocol based on a single transceiver. SFM-MAC uses an underwater passive localization algorithm to obtain location information and then transforms spatiotemporal information to avoid the synchronization of the whole network to reduce the spatiotemporal uncertainty of underwater networks; further, it uses request to send (RT)/channel announcement/channel listening/clear to send (CTS) handshaking mechanism to avoid multichannel hidden terminal problems and achieve fair access. In addition, the paper uses the Markov chain to construct the reservation model of control channels, and theoretically analyzes and calculates the theoretical throughput of the multichannel MAC protocol under the condition of reserved collision. Simulation experiments show that the network fairness index of SFM-MAC is 15% higher than that of traditional RTS/ CTS protocols. The effective network throughput of SFM-MAC in different business scenarios is 60–70% and 12–15% higher than the single-channel underwater MAC protocol SF acquisition multiple access and the multichannel underwater MAC protocol, respectively.

A channel assignment scheme for MIMO on concentric-hexagon-based multi-channel wireless networks

In a wireless network, multiple channels can increase network capacity. However, it causes other problems, e.g., multi-channel hidden terminal problem and the issue about how to allocate channels to wireless nodes. Basically, a well-defined channel assignment can avoid radio interference and improve transmission performance. Therefore, in this study, we proposed a multiple channel assignment scheme, called concentric-hexagon-oriented multi-channel assignment (CHOMA for short), in which all deployed eNBs are organized as concentric-hexagon (C-hexa for short). Available channels are grouped and then allocated to the C-hexas. We also arrange channels allocated to a C-hexa so as to reduce radio interference among its eNBs, consequentially improving the transmission capability and performance of a wireless network. Experimental results show that the CHOMA is really an interference-free scheme, no matter whether the target system is a network with SISO, SIMO, MISO or MIMO stations.

A channel assignment scheme for MIMO on concentric-hexagon-based multi-channel wireless networks

In a wireless network, multiple channels can increase network capacity. However, it causes other problems, e.g., multi-channel hidden terminal problem and the issue about how to allocate channels to wireless nodes. Basically, a well-defined channel assignment can avoid radio interference and improve transmission performance. Therefore, in this study, we proposed a multiple channel assignment scheme, called concentric-hexagon-oriented multi-channel assignment (CHOMA for short), in which all deployed eNBs are organized as concentric-hexagon (C-hexa for short). Available channels are grouped and then allocated to the C-hexas. We also arrange channels allocated to a C-hexa so as to reduce radio interference among its eNBs, consequentially improving the transmission capability and performance of a wireless network. Experimental results show that the CHOMA is really an interference-free scheme, no matter whether the target system is a network with SISO, SIMO, MISO or MIMO stations.

Triggered CCHI Multichannel MAC protocol for Vehicular Ad Hoc Networks

This paper proposes a Triggered CCHI Multichannel MAC protocol for efficient safety message dissemination in Vehicular Ad Hoc Networks. The proposed protocol allows a vehicle to start control channel interval (CCHI) by terminating service channel interval (SCHI) whenever a safety message arrives during SCHI. It enhances the performance of VANET by reducing resource wastage and unwanted delay caused by fixed interval of CCHI and SCHI. Further, CCHI keeps on increasing until all safety messages are not transmitted. A virtual TDMA beaconing process is also proposed in this paper to ensure delivery of periodic status messages. Multichannel hidden terminal problem is also addressed using cluster member request and cluster head request. An analytical model is developed to evaluate the proposed protocol with respect to packet delivery ratio, throughput, safety message delay and packet loss ratio. Extensive simulation is carried out to validate the analytical model and to demonstrate the improvement in comparison to existing similar MAC protocols and IEEE802.11p.

On Demand Stable Routing with Channel Allocation and Backoff Countdown Optimization in Wireless Mesh Networks

The multi-channel and multi-interface wireless mesh networks (WMNs) allow multiple orthogonal channels simultaneously to facilitate increased broadband connectivity to the end-users. Many efforts have been devoted to allocate the channels to the interfaces in a multi-channel multi-interface setting. Recently, the hybrid channel allocation mechanism jointly optimizes the routing and channel assignment, by utilizing the queuing traffic. It is essential to map the optimization of traffic distribution on each channel along with channel switching in such an order that it adapts to the changing traffic. However, the contention in medium access and channel switching delay are the key issues in a multi-channel hidden terminal problem. The proposed optimized stable path- channel allocation and routing (OSCAR) protocol is a hybrid multi-channel protocol that reduces the communication delay without degrading the network performance. The proposed work, OSCAR determines a highly stable path that increases mesh routers to improve the routing efficiency. The channel allocation mechanism mainly promotes queue dynamics based probabilistic channel selection (QDPCS), and backoff countdown optimization (BCO). An essential component of the QDPCS scheme is the factor of queuing utilization, and this strategy selects a least congested channel. The BCO mechanism creates the logical order among contending nodes based on the remaining backoff value. It reduces the medium access delay and enables the feasibility of scheduled transmissions without degrading the network throughput. Finally, the performance evaluation results show that the OSCAR protocol outperforms the existing protocol over WMNs.

Least Channel Variation Multi-Channel MAC (LCV-MMAC) under Mobile Random Topologies in Mobile Adhoc Networks

The use of multiple channels for transmissions has raised several challenges, for example, multi-channel hidden terminal problem, channel switching delay, and control channel saturation problem. Dedicated control channel techniques simplify channel coordination by eliminating the need for synchronization, however the control channel may become the bottleneck for the performance of the network. A better trade off which can solve the coordination problem, and can mitigate the control channel bottleneck is desirable. Least Channel Variant Multi-channel MAC (LCV-MMAC) is a multi-channel MAC based on IEEE 802.11 MAC. The novel part of this protocol is the channel assignment technique, where a mechanism to avoid unnecessary channel assignment and thus channel switching is used. Further, LCV-MMAC avoids channel contention when the control channel is highly saturated. In this paper, we explore the properties of LCV-MMAC through extensive simulations with the help of ns-2, and compare it with popular existing multi-channel MAC protocols in different mobile and static random topologies. Experimental results validate that LCV-MMAC achieves significantly better aggregated throughput, and fairness index than other multi-channel MAC protocols in different random network scenarios.

Load-aware channel hopping protocol design for mobile ad hoc networks

Using multiple channels in wireless networks improves spatial reuse and reduces collision probability and thus enhances network throughput. Designing a multi-channel MAC protocol is challenging because multi-channel-specific issues such as channel assignment, the multi-channel hidden terminal problem, and the missing receiver problem, must be solved. Most existing multi-channel MAC protocols suffer from either higher hardware cost or poor throughput. Some channel hopping multi-channel protocols achieve pretty good performance in certain situations but fail to adjust their channel hopping mechanisms according to varied traffic loads. In this paper, we propose a load-aware channel hopping MAC protocol (LACH) that solves all the multi-channel-specific problems mentioned above. LACH enables nodes to dynamically adjust their schedules based on their traffic loads. In addition to load awareness, LACH has several other attractive features: (1) Each node is equipped with a single half-duplex transceiver. (2) Each node's initial hopping sequence is generated by its ID. Knowing the neighbor nodes' IDs, a node can calculate its neighbors' initial channel hopping sequences without control packet exchanges. (3) Nodes can be evenly distributed among available channels. Through performance analysis, simulations, and real system implementation, we verify that LACH is a promising protocol suitable for a network with time-varied traffic loads.

DCR-MAC: a data channel recommending MAC for multi-channel WLANs toward the higher throughput performance

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.

Design of an Efficient MAC Protocol for Opportunistic Cognitive Radio Networks

Cognitive radio technology has been develo ped in recent years to make efficient use of the wireless spectrum especially for opportunistic spectrum access. Cognitive radio technology enables the secondary (cognitive) users to use the unused licensed spectrum of the primary users.Medium Access Control(MAC) protocol plays a vital role in spectrum utilization, primary user’s (PU) interference management and secondary user’s coordination in cognitive radio (CR) networks. Here, we propose a new MAC protocol where control transceiver attached with sensor improves the accuracy of spectrum sensing result as well as protects the primary user from interference.In our proposed MAC protocol , each secondary user (SU) is equipped with two radios, solves the multichannel hidden terminalproblem (MHTP). Our proposed MAC protocol considers collision avoidance among SU’s and between SU’s and PU’s. We develop an analytical model validated by simulation. Our scheme improvesthe network throughput in presence of sensing error.

Cognitive Radio Ad-Hoc Networks: Some New Results on Multi-Channel Hidden Terminal Problem

Recently the Cognitive Radio (CR), in particular the CR Ad-Hoc Network (CRAHN) technology appears as a burgeoning area in wireless communication that enables utilization of limited network resources in more efficient and intelligent way; studies indicate that opportunistic utilization of the available radio frequency spectrum, without interfering the licensed primary user (PU) could be made. This paper presents some simulation based performance of the Multi-Channel Hidden Terminal (MCHT) problem on CRAHNs; new observations on the effect of the number of channels on certain PU-activity metrics, e.g., delay and throughput, are described.

Design of OMC-MAC: An Opportunistic Multi-Channel MAC with QoS Provisioning for Distributed Cognitive Radio Networks

Dynamic resource availability and lack of central control unit offer many challenges while designing medium access control (MAC) protocol for a distributed cognitive radio network (DCRN). In this paper, we propose a novel MAC design for DCRN which provides an efficient approach to address quality of service (QoS) requirements of delay sensitive applications by defining higher priority to such applications during channel reservation. It also combats other major challenges such as efficient spectrum utilization, multi-channel hidden terminal problem (MHTP) and collision with primary user (PU) due to sensing error at SU. We develop an analytical framework to study the performance of the proposed protocol. We then compare the performance of proposed protocol with those of two existing protocols. Comparison results show that proposed MAC outperforms the existing protocols by providing better throughput and reducing DCRN users' collision probability with PUs in presence of sensing error. The results achieved from the analytical model and validated by simulations show that our simple yet efficient design identifies and fulfils the QoS requirements of delay sensitive applications, achieves excellent spectrum utilization, shows superb robustness in presence of sensing errors and handles MHTP effectively.

Synchronisation-based, multi-channel multi-interface medium access scheme in ad hoc network

Multi-channel multi-interface (MCMI) medium access can provide high-throughput services for wireless ad hoc networks. However, the multi-channel hidden terminal problem and the rendezvous problem must be addressed. This study aims to design a low-cost integrated solution to address the two problems, so as to fully exploit the available wireless interfaces and channels to enhance the network performance, especially the network aggregated throughput. The authors propose a new MCMI synchronisation-based media access control (SMAC) protocol with the operation of two interfaces. Unlike other studies, the authors propose a novel interface classification using a synchronisation interface (SynIF) and a normal interface (NorIF). A synchronisation mechanism and a new channel coordination procedure are operated on SynIF, and data packets can be transmitted on SynIF and NorIF concurrently. All control messages occur only in a variable-length channel coordination window (CCW) on a common control channel. The maximum length of CCW and network throughput are analysed mathematically and the performance of the protocol is validated in ns-2 simulator through comparisons with few other MCMI-MAC protocols. In IEEE 802.11-based multi-interface ad hoc networks, when using MCMI-SMAC, the results show that the network aggregated throughput is enhanced significantly and the protocol overhead is very low.

CREAM-MAC: Cognitive Radio-EnAbled Multi-Channel MAC Protocol Over Dynamic Spectrum Access Networks

As the novel and effective approach to improving the utilization of the precious radio spectrum, cognitive radio technology is the key to realize the dynamic spectrum access (DSA) networks, where the secondary (unlicensed) users can opportunistically utilize the unused licensed spectrum in a way that confines the level of interference to the range the primary (licensed) users can tolerate. However, there are many new challenges associated with cognitive-radio-based DSA networks, such as the multi-channel hidden terminal problem and the fact that the time-varying channel availability differs for different secondary users, in the medium access control (MAC) layer. To overcome these challenges, we propose an efficient Cognitive Radio-EnAbled Multi-channel MAC (CREAM-MAC) protocol, which integrates the cooperative sequential spectrum sensing at physical layer and the packet scheduling at MAC layer, over the wireless DSA networks. Under the proposed CREAM-MAC protocol, each secondary user is equipped with a cognitive radio-enabled transceiver and multiple channel sensors. Our cooperative sequential spectrum sensing scheme improves the accuracy of spectrum sensing and further protects the primary users. The proposed CREAM-MAC enables the secondary users to best utilize the unused frequency spectrum while avoiding the collisions among secondary users and between secondary users and primary users. We develop the Markov chain model and M/GY/1 queueing model to rigorously study our proposed CREAM-MAC protocol for both the saturation networks and the non-saturation networks. We also conduct extensive simulations to validate our developed protocol and analytical models.

An Energy Efficient Multichannel MAC Protocol for QoS Provisioning in MANETs

This paper proposes a TDMA-based multichannel medium access control (MAC) protocol for QoS provisioning in mobile ad hoc networks (MANETs) that enables nodes to transmit their packets in distributed channels. The IEEE 802.11 standard supports multichannel operation at the physical (PHY) layer but its MAC protocol is designed only for a single channel. The single channel MAC protocol does not work well in multichannel environment because of the multichannel hidden terminal problem. Our proposed protocol enables nodes to utilize multiple channels by switching channels dynamically, thus increasing network throughput. Although each node of this protocol is equipped with only a single transceiver but it solves the multichannel hidden terminal problem using temporal synchronization. The proposed energy efficient multichannel MAC (EM-MAC) protocol takes the advantage of both multiple channels and TDMA, and achieves aggressive power savings by allowing nodes that are not involved in communications to go into power saving “sleep mode”. We consider the problem of providing QoS guarantee to nodes as well as to maintain the most efficient use of scarce bandwidth resources. Our scheme improves network throughput and lifetime significantly, especially when the network is highly congested. The simulation results show that our proposed scheme successfully exploits multiple channels and significantly improves network performance by providing QoS guarantee in MANETs.

Exploiting maximum performance of multichannel multiple access using half-duplex transceiver

A slot-optimised multichannel medium access control (SO-MMAC) protocol is proposed to resolve the multichannel hidden terminal problem and control channel (CCH) bottleneck problem for multihop ad hoc networks. It adjusts the relationship between the reservation slot (RS) on the CCH and the data packet transmission slot on the data channel (DCH) to achieve the best load balance and default collision-free DCH selection without establishing a channel state table, and then greatly enhances multiple access efficiency. A reservation scheme with minimum handshakes and RS and contention micro-slot backoff mechanisms is also proposed to effectively decrease control overhead and packet collisions. Simulation results show that SO-MMAC has better performance compared to the traditional MAC protocol.

A coordinated multiple channel assignment scheme and AP deployment for channel reuse in metropolitan scale wireless networks

In a wireless network, when a single channel is employed, hidden terminal and radio interference problems may occur. The two problems are the main factors that cause low network throughput. In fact, the hidden node problem results from radio interference. Up to the present, many researchers have used multi-channel schemes to solve the interference problem. However, a multi-channel system causes other problems, e.g., the multi-channel hidden terminal problem, and the channel assignment problem. Actually, a well-defined channel assignment can effectively solve the former problem. Therefore, in this paper, we propose a multi-channel assignment system, called a corona- oriented multi-channel assignment system (COMAS for short), which as a metropolitan scale system coordinates channel usage for wireless networks to mitigate radio interference among APs and nodes so as to improve network throughput and efficiency, particularly when many nodes are connected to APs. In the COMAS, APs are deployed as concentric circles, named coronas, and channels are grouped and then allocated to coronas. We also cluster APs into groups, and schedule available channels to avoid radio interference and multi-channel hidden terminal problems among adjacent AP groups and among APs in a group. Simulation results show that the COMAS can effectively improve wireless-network throughput, drop rate, packet delivery delay and jitter.

AMNP: ad hoc multichannel negotiation protocol with broadcast solutions for multi-hop mobile wireless networks

A multi-hop mobile ad hoc network (MANET) is generally configured as a peer-to-peer network with no centralised hubs or controllers that coordinate channel resources. Nodes in a MANET usually equip one single transceiver for data transmissions. However, the single transceiver architecture will cause a difficulty of being implemented in multichannel environment if the network transmission capacity would be improved by adopting parallel multichannel access. To solve this thorny problem, this study presents a distributed medium access control (MAC) layer protocol called ad hoc multichannel negotiation protocol (AMNP) for multichannel transmissions in the multi-hop MANET. Additionally, two problems, the multichannel hidden terminal problem and the multichannel broadcast transmission problem, caused by single transceiver operations in the multichannel environment, which have not been revealed in academia, is presented and solved in this study. Finally, an enhanced AMNP with channel scheduling (AMNP/s) scheme is introduced to improve the channel utilisation. The author show, via simulations, that AMNP/s provides a higher throughput compared to its single-channel counterpart by promoting simultaneous transmissions in different channels. Simulation results also show that AMNP/s derives higher performance than other multichannel transmission schemes that use multiple transceivers.