Multi-channel mac for ad hoc networks: handling multi-channel hidden terminals using a single transceiver
24 May 2004-pp 222-233
TL;DR: This paper proposes a medium access control (MAC) protocol for ad hoc wireless networks that utilizes multiple channels dynamically to improve performance and solves the multi-channel hidden terminal problem using temporal synchronization.
Abstract: This paper proposes a medium access control (MAC) protocol for ad hoc wireless networks that utilizes multiple channels dynamically to improve performance. The IEEE 802.11 standard allows for the use of multiple channels available at the physical layer, but its MAC protocol is designed only for a single channel. A single-channel MAC protocol does not work well in a multi-channel environment, because of the multi-channel hidden terminal problem . Our proposed protocol enables hosts to utilize multiple channels by switching hannels dynamically, thus increasing network throughput. The protocol requires only one transceiver per host, but solves the multi-channel hidden terminal problem using temporal synchronization. Our scheme improves network throughput signifiantly, especially when the network is highly congested. The simulation results show that our protocol successfully exploits multiple hannels to achieve higher throughput than IEEE 802.11. Also, the performance of our protocol is comparable to another multi-hannel MAC protocol that requires multiple transceivers per host. Since our protocol requires only one transceiver per host, it an be implemented with a hardware complexity comparable to IEEE 802.11.
Citations
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TL;DR: This paper presents a detailed study on recent advances and open research issues in WMNs, followed by discussing the critical factors influencing protocol design and exploring the state-of-the-art protocols for WMNs.
4,205 citations
Cites background from "Multi-channel mac for ad hoc networ..."
...A clear understanding of the relationship between network capacity and the above factors provides a guideline for protocol development, architecture design, deployment and operation of the network....
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TL;DR: A detailed investigation of current state-of-the-art protocols and algorithms for WMNs is presented and open research issues in all protocol layers are discussed to spark new research interests in this field.
Abstract: Wireless mesh networks (WMNs) have emerged as a key technology for next-generation wireless networking. Because of their advantages over other wireless networks, WMNs are undergoing rapid progress and inspiring numerous applications. However, many technical issues still exist in this field. In order to provide a better understanding of the research challenges of WMNs, this article presents a detailed investigation of current state-of-the-art protocols and algorithms for WMNs. Open research issues in all protocol layers are also discussed, with an objective to spark new research interests in this field.
1,785 citations
Cites methods from "Multi-channel mac for ad hoc networ..."
...To coordinate transmissions between network nodes under this situation, protocols such as the multi-channel MAC in [4] are needed....
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13 Mar 2005
TL;DR: It is shown that intelligent channel assignment is critical to Hyacinth's performance, and distributed algorithms that utilize only local traffic load information to dynamically assign channels and to route packets are presented, and their performance is compared against a centralized algorithm that performs the same functions.
Abstract: Even though multiple non-overlapped channels exist in the 2.4 GHz and 5 GHz spectrum, most IEEE 802.11-based multi-hop ad hoc networks today use only a single channel. As a result, these networks rarely can fully exploit the aggregate bandwidth available in the radio spectrum provisioned by the standards. This prevents them from being used as an ISP's wireless last-mile access network or as a wireless enterprise backbone network. In this paper, we propose a multi-channel wireless mesh network (WMN) architecture (called Hyacinth) that equips each mesh network node with multiple 802.11 network interface cards (NICs). The central design issues of this multi-channel WMN architecture are channel assignment and routing. We show that intelligent channel assignment is critical to Hyacinth's performance, present distributed algorithms that utilize only local traffic load information to dynamically assign channels and to route packets, and compare their performance against a centralized algorithm that performs the same functions. Through an extensive simulation study, we show that even with just 2 NICs on each node, it is possible to improve the network throughput by a factor of 6 to 7 when compared with the conventional single-channel ad hoc network architecture. We also describe and evaluate a 9-node Hyacinth prototype that Is built using commodity PCs each equipped with two 802.11a NICs.
1,636 citations
TL;DR: A detailed performance evaluation shows that with intelligent channel and bandwidth assignment, equipping every wireless mesh network node with just 2 NICs operating on different channels can increase the total network goodput by a factor of up to 8 compared with the conventional single-channel ad hoc network architecture.
Abstract: The IEEE 802.11 Wireless LAN standards allow multiple non-overlapping frequency channels to be used simultaneously to increase the aggregate bandwidth available to end-users. Such bandwidth aggregation capability is routinely used in infrastructure mode operation, where the traffic to and from wireless nodes is distributed among multiple interfaces of an access point or among multiple access points to balance the traffic load. However, bandwidth aggregation is rarely used in the context of multi-hop 802.11-based LANs that operate in the ad hoc mode. Most past research efforts that attempt to exploit multiple radio channels require modifications to the MAC protocol and therefore do not work with commodity 802.11 interface hardware. In this paper, we propose and evaluate one of the first multi-channel multi-hop wireless ad-hoc network architectures that can be built using standard 802.11 hardware by equipping each node with multiple network interface cards (NICs) operating on different channels. We focus our attention on wireless mesh networks that serve as the backbone for relaying end-user traffic from wireless access points to the wired network. The idea of exploiting multiple channels is particularly appealing in wireless mesh networks because of their high capacity requirements to support backbone traffic. To reap the full performance potential of this architecture, we develop a set of centralized channel assignment, bandwidth allocation, and routing algorithms for multi-channel wireless mesh networks. A detailed performance evaluation shows that with intelligent channel and bandwidth assignment, equipping every wireless mesh network node with just 2 NICs operating on different channels can increase the total network goodput by a factor of up to 8 compared with the conventional single-channel ad hoc network architecture.
1,318 citations
Cites methods from "Multi-channel mac for ad hoc networ..."
...…shows that with intelligent channel and bandwidth assignment, equipping every wireless mesh network node with just 2 NICs operating on different channels can increase the total network goodput by a factor of up to 8 compared with the conventional single-channel ad hoc network architecture....
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26 Sep 2004
TL;DR: A link-layer protocol called Slotted Seeded Channel Hopping, or SSCH, is presented that increases the capacity of an IEEE 802.11 network by utilizing frequency diversity and uses a novel scheme for distributed rendezvous and synchronization.
Abstract: Capacity improvement is one of the principal challenges in wireless networking. We present a link-layer protocol called Slotted Seeded Channel Hopping, or SSCH, that increases the capacity of an IEEE 802.11 network by utilizing frequency diversity. SSCH can be implemented in software over an IEEE 802.11-compliant wireless card. Each node using SSCH switches across channels in such a manner that nodes desiring to communicate overlap, while disjoint communications mostly do not overlap, and hence do not interfere with each other. To achieve this, SSCH uses a novel scheme for distributed rendezvous and synchronization. Simulation results show that SSCH significantly increases network capacity in several multi-hop and single-hop wireless networking scenarios.
985 citations
References
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01 Jan 1996
2,375 citations
TL;DR: The busy-tone multiple-access mode is introduced and analyzed as a natural extension of CSMA to eliminate the hidden-terminal problem and results show that BTMA with hidden terminals performs almost as well as CSMA without hidden terminals.
Abstract: We consider a population of terminals communicating with a central station over a packet-switched multiple-access radio channel. The performance of carrier sense multiple access (CSMA) [1] used as a method for multiplexing these terminals is highly dependent on the ability of each terminal to sense the carrier of any other transmission on the channel. Many situations exist in which some terminals are "hidden" from each other (either because they are out-of-sight or out-of-range). In this paper we show that the existence of hidden terminals significantly degrades the performance of CSMA. Furthermore, we introduce and analyze the busy-tone multiple-access (BTMA) mode as a natural extension of CSMA to eliminate the hidden-terminal problem. Numerical results giving the bandwidth utilization and packet delays are shown, illustrating that BTMA with hidden terminals performs almost as well as CSMA without hidden terminals.
1,754 citations
"Multi-channel mac for ad hoc networ..." refers background or methods in this paper
...This whole process is called Virtual Carrier Sensing, which allows the area around the sender and receiver to be reserved for communication, thus avoiding the hidden terminal problem [ 10 ]....
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...In this section, we describe a new type of hidden terminal problem [ 10 ] pertaining to multi-channel environment, which we call the multi-channel hidden terminal problem....
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07 Dec 2000
TL;DR: A new multi-channel MAC protocol is proposed, which follows an "on-demand" style to assign channels to mobile hosts and flexibly adapts to host mobility and only exchanges few control messages to achieve channel assignment and medium access.
Abstract: The wireless mobile ad hoc network (MANET) architecture has received a lot of attention recently. This paper considers the access of multiple channels in a MANET with multi-hop communication behavior. We point out several interesting issues when using multiple channels. We then propose a new multi-channel MAC protocol, which is characterized by the following features: (i) it follows an "on-demand" style to assign channels to mobile hosts, (ii) the number of channels required is independent of the network topology and degree, (iii) it flexibly adapts to host mobility and only exchanges few control messages to achieve channel assignment and medium access, and (iv) no clock synchronization is required. Compared to existing protocols, some assign channels to hosts statically (thus a host will occupy a channel even when it has no intention to transmit) some require a number of channels which is a function of the maximum connectivity, and some necessitate a clock synchronization among all hosts in the MANET. Extensive simulations are conducted to evaluate the proposed protocol.
776 citations
"Multi-channel mac for ad hoc networ..." refers background or methods in this paper
...11 single channel MAC, the curves labeled as “DCA” indicate the DCA protocol from [8], and the curves labeled as “MMAC” indicate our proposed scheme....
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...The protocol is similar to [8], except it assumes each node has one transceiver....
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...[9] propose a protocol that uses a scheme similar to [8] that has one control channel and N data channels, but selects the best channel according to the channel condition at the receiver side....
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...11, and the Dynamic Channel Assignment (DCA) protocol [8] (DCA was explained in section II)....
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...The proposed scheme requires only one transceiver for each host, while other multi-channel MAC protocols require multiple transceivers for each host [11, 9, 8]....
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TL;DR: In this article, the authors provide a top-level perspective on how the global positioning system works, how its services are used, and delves into the most important technical and geo-political factors affecting its long-term availability in an international setting.
Abstract: The paper provides a top-level perspective on how the global positioning system works, how its services are used, and delves into the most important technical and geo-political factors affecting its long-term availability in an international setting.
554 citations
23 Sep 2000
TL;DR: A medium access control (MAC) protocol for an ad hoc network of mobile wireless terminals that are equipped with multiple directional antennas and results obtained from detailed computer simulations demonstrate the performance improvement obtained with the proposed scheme.
Abstract: We propose a medium access control (MAC) protocol for an ad hoc network of mobile wireless terminals that are equipped with multiple directional antennas. Use of directional antennas in ad hoc networks can largely reduce the radio interference, thereby improving the packet throughput. However, the main problem of using directional antennas in such networks is due to the dynamic nature of the network caused by frequent node movements. This gives rise to problems such as locating and tracking during random channel access. The MAC protocol presented in this paper proposes a solution to these problems without the help of additional hardware. Results obtained from detailed computer simulations demonstrate the performance improvement obtained with the proposed scheme.
549 citations
"Multi-channel mac for ad hoc networ..." refers background in this paper
...The proposed scheme requires only one transceiver for each host, while other multi-channel MAC protocols require multiple transceivers for each host [11, 9, 8]....
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...Unlike our scheme, many other multi-channel MAC protocols require each host to have multiple transceivers [11, 9, 8]....
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