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On Medium Access for Wireless Ad-hoc and Sensor Networks

Arash Tahmasebi Toyserkani (Institutionen för signaler och system, Kommunikationssystem)
Göteborg : Chalmers University of Technology, 2007.
[Licentiatavhandling]

The medium access control (MAC) is a sub-layer of the data link layer, the second layer of the open system interconnection (OSI) model. The MAC sub-layer is responsible for organizing the access to the shared channel and it is due to this important responsibility that the performance of networks is substantially influenced by the MAC protocol. This thesis is based on three contributions, addressing different issues related to the MAC layer of a variety of wireless networks.

The first contribution in this thesis, paper A, deals with the problem of designing a MAC protocol for vehicle-to-vehicle (V2V) communication for traffic safety purposes. Traffic safety applications often require to broadcast information or warning packets to all the vehicles in a close vicinity with as little delay as possible. CSMA-based protocols, which is one of the candidates for the V2V communication MAC, suffer from lack of an efficient and reliable broadcast method. To address this problem, a new broadcast scheme called Long Range Busy Tone (LRBT) is proposed.

Two important ranges in the MAC layer, namely the transmission and interference ranges, are the topics of the second contribution of this thesis. Weaknesses of the current model for interference range are discussed and an improved model is obtained by removing some of the simplifying assumptions. Additionally, the effects of physical layer parameters and a fading channel on transmission and interference ranges are discussed.

The last part of this thesis is devoted to scheduling co-existing time-slotted clusters in a Rayleigh fading channel. In this fading channel, no distance separation guarantees interference free communication. Therefore, the co-channel interference can be only minimized, if a joint scheduling among all the clusters is considered. In paper C, this joint scheduling problem, which is known to be NP-hard, is sub-optimally solved based on Lagrangian relaxation and the auction algorithm.

Nyckelord: MAC, Taffic Safety, Sensor Networks, CSMA, TDMA, Transmission range, Interference range



Denna post skapades 2007-05-24. Senast ändrad 2008-04-09.
CPL Pubid: 42051

 

Institutioner (Chalmers)

Institutionen för signaler och system, Kommunikationssystem

Ämnesområden

Telekommunikationsteori

Chalmers infrastruktur

Relaterade publikationer

Inkluderade delarbeten:


An Efficient Broadcast MAC Scheme for Traffic Safety Applications in Automotive Networks


On the MAC Protocols of Co-Existing Time-Slotted Sensor Networks


Improved Model for Transmission and Interference Ranges


Examination

Datum: 2007-06-05
Tid: 10:00
Lokal: EA, Hörsalsvägen 11, floor 4, Chalmers
Opponent: Professor Hannes Hartstein, DSN Research Group, Institute of Telematics, University of Karlsruhe, Germany