Throughput Improvement Technique for D-TDMA-Based Vehicular Ad-Hoc Networks

Mathieu LENOBLE  Kenji ITO  

IEICE TRANSACTIONS on Communications   Vol.E94-B   No.10   pp.2776-2784
Publication Date: 2011/10/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E94.B.2776
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Network
ITS,  VANET,  D-TDMA,  Time slot redundancy,  Huffman codes,  

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In the decentralized-TDMA (D-TDMA) protocol, the terminals select a free slot based on the frame information (FI) which is a representation of the status of each slot in the network. The FI, however, constitutes a large portion of the packet, which seriously compromises the per-packet transport capacity of the D-TDMA protocol. We therefore propose an opportunistic header management scheme for increasing the number of payload bytes without adversely affecting the performance of the D-TDMA. Our proposal is based on every terminal being able to choose between two techniques for transmitting their data packets. The first, based on the FI redundancies, lets the terminals transmit only the relevant information. The second compresses the FI with a lossless data compressor, i.e. the Huffman algorithm. Computer simulations were conducted for an urban environment in which vehicles are moving. The simulation results show that the proposed technique significantly increases the throughput without degrading the quality of the D-TDMA protocol.