Application level phase adjustment for maximizing the fairness in VANET

Batsuuri, Tseesuren; Bril, Reinder J.; Lukkien, Johan J.

doi:10.1109/mass.2010.5663797

Cited by 6 publications

(3 citation statements)

References 10 publications

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“…Upon a successful frame reception, the receiving STA sends back an ACK frame to the source. Like for a CTS frame, the intended receiver waits for a Shorter Inter-Frame Space (SIFS), the shortest of the IFSs, 3 prior to transmit an ACK. If the ACK is not received, the frame is considered as lost and retransmitted by the source node after a mandatory IFS and an additional random delay.…”

Section: Distributed Coordination Functionmentioning

confidence: 99%

“…The CTS transmitted by the destination restates the same channel reservation, so that neighboring nodes which are not able to hear the source (e.g., hidden terminals) may set the NAV and refrain from accessing the channel. 3 The 802.11 MAC layer mandates that a gap of a minimum specified duration, IFS, exists between contiguous frame sequences. …”

mentioning

confidence: 99%

“…Actually, the first requirement (real-time transmission) is only apparently an issue: broadcast traffic-due to the lack of exponential back-off-is never delayed significantly [19], although channel access delay is unpredictable for CSMA/CA under heavy load conditions; conversely the number of collisions grows and this affects both reliability [12,13,15,19] and fairness [3]. Once more, a partial solution is represented by DCC mechanisms.…”

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confidence: 99%

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The MAC Layer of VANETs

Campolo

Molinaro

Scopigno

et al. 2015

Vehicular Ad Hoc Networks

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The design of the Medium Access Control (MAC) layer for vehicular networks should carefully cope with fast changing topologies caused by vehicle mobility, short connection lifetimes, harsh propagation environments, high node density, and heterogeneous traffic nature and quality demands. This chapter provides a detailed description of MAC functions (i.e., channel access rules, prioritization schemes, frame types, and formats), as specified by the IEEE 802.11p and ETSI ITS-G5 standards, and the multichannel operation. By discussing the main challenges which the MAC has to deal with, the chapter also presents the main evaluation tools (analytics, simulations, field-tests) that can be used to analyze the MAC performance. IntroductionSince the beginning of research on Vehicular ad-hoc networks (VANETs), in the early 1990s, different wireless technologies have been considered to support vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communications with the primary goal of enabling cooperative safety applications.The MAC layer, whatever the access technology, plays a crucial role in regulating the access to the common wireless medium so that multiple stations share it efficiently. The most pressing requirement for a MAC in a vehicular environment was for a decentralized operation, without a coordinator and/or a central manager in charge of ruling the channel access or the resource assignment. This way, vehicular nodes are enabled to communicate without explicitly joining the network (i.e., associating with the access point or the base station playing the coordinator role).Among available radio technologies, the simple and worldwide well-known IEEE 802.11 [27] technology was considered the best candidate to enable V2V and V2I wireless communications; notably, it also guaranteed the perspective of supporting services other than safety (such as automated tolling, enhanced navigation, and traffic management). Initially proposed as an amendment to the IEEE 802.11, 802.11p is now part of the last IEEE 802.11 standard [27] and represents the de facto solution for vehicular communications.This decision was one of the few shared between the IEEE 1609 family of standards for Wireless Access in Vehicular Environments (WAVE) and the European profile standard of Intelligent Transport Systems (ITS) operating in the 5 GHz frequency band standardized by ETSI (ITS-G5) [28].IEEE 802.11p inherits the main operating principles of the 802.11 technology, however, unlike 802.11, it has been specifically conceived to provide short-tomedium range connectivity (in a range up to 1,000 m) to fast moving vehicles in a very different environment compared to wireless office/home. Many other differences might (and will) be highlighted in Sect. 4.2.Summing up:• VANETs adopt the same PHY-MAC layers of IEEE 802.11;• the PHY layer, relying on Orthogonal Frequency Division Multiplexing (OFDM) as discussed in Chap. 3, has been slightly modified for VANETs and, in most cases, it now suits the VANETs' requirements-with exception of tho...

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Section: Distributed Coordination Functionmentioning

confidence: 99%

mentioning

confidence: 99%