Throughput Enhancement for Mobile Ad Hoc Networks by Using Transfer Rate Adaptation, Back-to-Back Transmission, and Frame Fragmentation

Chien-Yuan LIU  Chun-Hung LIN  

IEICE TRANSACTIONS on Communications   Vol.E87-B    No.5    pp.1064-1074
Publication Date: 2004/05/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Mobile Multimedia Communications)
Category: Ad-hoc Network
WLAN,  MANET,  multi-rate,  adaptation,  fragmentation,  back-to-back transmission,  

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Multi-rate capabilities are supported by the physical layers of most 802.11 devices. To enhance the network throughput of MANETs, transfer rate adaptation schemes at MAC layer should employ the multi-rate capability at physical and the information of previous transmissions provided by MAC and physical layers. In this paper, we propose a transfer rate adaptation scheme plus back-to-back frame transmissions, and fragmentation at MAC layer, named TRAF. TRAF adopts a bi-direction-based approach with an extended option to select an appropriate rate for frame transmission under fast changing channel conditions. Consecutive back-to-back frame transmissions to fully utilize good channel quality during a coherent time interval and fragmentation algorithm to maintain high throughput under worse channel conditions are recommended in TRAF. Extensive simulation is experimented to evaluate the performance of TRAF. Regarding simulation results, frame delivery ratio, network throughput, and fairness of TRAF are significantly improved by comparing to that of fix rate, ARF, RBAR, OAR, and AAR protocols.