A scalable model for channel access protocols in multihop ad hoc networks

Carvalho, Marcelo M.; Garcia-Luna-Aceves, J.J.

doi:10.1145/1023720.1023753

Cited by 108 publications

(122 citation statements)

References 47 publications

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“…References [19] and [20] incorporate the considerations for multihop flows. Our objective is to obtain the total voice call carrying capacity for an IEEE 802.11b network.…”

Section: Ieee 80211b Dcf Performancementioning

confidence: 99%

Sticky CSMA/CA: Implicit synchronization and real-time QoS in mesh networks

et al. 2007

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We propose a novel approach to QoS for real-time traffic over wireless mesh networks, in which application layer characteristics are exploited or shaped in the design of medium access control. Specifically, we consider the problem of efficiently supporting a mix of Voice over IP (VoIP) and delay-insensitive traffic, assuming a narrowband physical layer with CSMA/CA capabilities. The VoIP call carrying capacity of wireless mesh networks based on classical CSMA/CA (e.g., the IEEE 802.11 standard) is low compared to the raw available bandwidth, due to lack of bandwidth and delay guarantees. Time Division Multiplexing (TDM) could potentially provide such guarantees, but it requires fine-grained network-wide synchronization and scheduling, which are difficult to implement. In this paper, we introduce Sticky CSMA/CA, a new medium access mechanism that provides TDM-like performance to real-time flows without requiring explicit synchronization. We exploit the natural periodicity of VoIP flows to obtain implicit synchronization and multiplexing gains. Nodes monitor the medium using the standard CSMA/CA mechanism, except that they remember the recent history of activity in the medium. A newly arriving VoIP flow uses this information to grab the medium at the first available opportunity, and then sticks to a periodic schedule, providing delay and bandwidth guarantees. Delay-insensitive traffic fills the gaps left by the real-time flows using novel contention mechanisms to ensure efficient use of the leftover bandwidth. Large gains over IEEE 802.11 networks are demonstrated in terms of increased voice call carrying capacity (more than 100% in some cases). We briefly discuss extensions of these ideas to a broader class of real-time applications, in which artificially imposing periodicity (or some other form of regularity) at the application layer can lead to significant enhancements of QoS due to improved medium access.

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“…References [19] and [20] incorporate the considerations for multihop flows. Our objective is to obtain the total voice call carrying capacity for an IEEE 802.11b network.…”

Section: Ieee 80211b Dcf Performancementioning

confidence: 99%

Sticky CSMA/CA: Implicit synchronization and real-time QoS in mesh networks

et al. 2007

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“…Analytical models for packet-level performance in ad-hoc networks are presented in e.g. [5,12,14,24]. These papers assume that stations have a limited interference range and after stations are distributed on a plain, the stations experience different channel-conditions as the number of neighbors and the distances to the neighbors varies per station.…”

Section: Literaturementioning

confidence: 99%

Performance Modeling of a Bottleneck Node in an IEEE 802.11 Ad-Hoc Network

Berg

Mandjes

Roijers

2006

Ad-Hoc, Mobile, and Wireless Networks

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C e n t r u m v o o r W i s k u n d e e n I n f o r m a t i c a PNA Probability, Networks and Algorithms Probability, Networks and AlgorithmsPerformance modeling of a bottleneck node in an IEEE 802.11 ad-hoc network J.L. van Performance modeling of a bottleneck node in an IEEE 802.11 ad-hoc network ABSTRACT This paper presents a performance analysis of wireless ad-hoc networks, with IEEE 802.11 as the underlying Wireless LAN technology. WLAN has, due to the fair radio resource sharing at the MAC-layer, the tendency to share the capacity equally amongst the active nodes, irrespective of their loads. An inherent drawback of this sharing policy is that a node that serves as a relay-node for multiple flows is likely to become a bottleneck. This paper proposes to model such a bottleneck by a fluid-flow model. Importantly, this is a model at the flow-level: flows arrive at the bottleneck node, and are served according to the sharing policy mentioned above. Assuming Poisson initiations of new flow transfers, we obtain insightful, robust, and explicit expressions for characteristics related to the overall flow transfer time, the buffer occupancy, and the packet delay at the bottleneck node. The analysis is enabled by a translation of the buffer dynamics at the bottleneck node in terms of an M/G/1 queueing model. We conclude the paper by an assessment of the impact of alternative sharing policies (which can be obtained by the IEEE 802.11E version), in order to improve the performance of the bottleneck. Abstract This paper presents a performance analysis of wireless ad-hoc networks, with ieee 802.11 as the underlying wireless lan technology. wlan has, due to the fair radio resource sharing at the mac-layer, the tendency to share the capacity equally amongst the active nodes, irrespective of their loads. An inherent drawback of this sharing policy is that a node that serves as a relay-node for multiple flows is likely to become a bottleneck. This paper proposes to model such a bottleneck by a fluid-flow model. Importantly, this is a model at the flow-level: flows arrive at the bottleneck node, and are served according to the sharing policy mentioned above. Assuming Poisson initiations of new flow transfers, we obtain insightful, robust, and explicit expressions for characteristics related to the overall flow transfer time, the buffer occupancy, and the packet delay at the bottleneck node. The analysis is enabled by a translation of the buffer dynamics at the bottleneck node in terms of an m/g/1 queueing model. We conclude the paper by an assessment of the impact of alternative sharing policies (which can be obtained by the ieee 802.11e version), in order to improve the performance of the bottleneck.

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“…In the following, we augment the modeling framework originally introduced in [12] to include, among other things, a general treatment of the impact of the carrier sensing activity in general ad hoc networks. The model we introduced in [12] captures the interactions between the PHY and MAC layers and takes into account the radio connectivity among the nodes.…”

Section: The Directional Virtual Carrier Sensing (Dvcs) Protocolmentioning

confidence: 99%

“…Section IV presents our new analytical model, which is derived from our previous work [12], and captures the interactions between the physical and the MAC layers while taking into account the radio connectivity among nodes. The extensions and modifications of our new analytical model include: (a) taking into account the impact of packet flow distribution among multiple receivers; (b) expressing the impact of frame size distribution; (c) modeling the impact of the carrier sensing mechanism in carrier-sensing MAC protocols; and (d) providing richer interference matrices that explicitly model the impact of a node's transmission on the SINR degradation of every other node, i.e., the effect of capture with respect to every potential interferer is treated individually.…”

Section: Introductionmentioning

confidence: 99%

Modeling Wireless Ad Hoc Networks with Directional Antennas

Carvalho

Garcia-Luna-Aceves

2006

Proceedings IEEE INFOCOM 2006. 25TH IEEE International Conference on Computer Communications

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Abstract-This paper presents the first analytical model of wireless ad hoc networks that considers the impact of realistic antenna-gain patterns on network performance. As such, our modeling approach allows the study of ad hoc networks in which nodes are equipped with directional antennas. This modeling capability stands out from all previous analytical models, which have only dealt with omnidirectional or over-simplified antenna gain patterns, and which have not addressed the specific mechanisms of the medium access control (MAC) protocols used (e.g., the backoff mechanism). A new analytical model for the IEEE 802.11 DCF MAC is introduced that allows the study of different carrier-sensing mechanisms, such as the directional virtual carrier sensing (DVCS) protocol that we use to validate our analytical model and show its applicability. Our numerical results show that our new analytical model predicts the results obtained by discrete-event simulations very accurately, and does it with a processing time that is orders of magnitude faster than the time required by simulations.

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A scalable model for channel access protocols in multihop ad hoc networks

Cited by 108 publications

References 47 publications

Sticky CSMA/CA: Implicit synchronization and real-time QoS in mesh networks

Sticky CSMA/CA: Implicit synchronization and real-time QoS in mesh networks

Performance Modeling of a Bottleneck Node in an IEEE 802.11 Ad-Hoc Network

Modeling Wireless Ad Hoc Networks with Directional Antennas

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