Soft-TDMAC: A Software TDMA-Based MAC over Commodity 802.11 Hardware

Author

Djukic, Petar ; Mohapatra, Prasant

Author_Institution

Dept. of Syst. & Comput. Eng., Carleton Univ., Ottawa, ON

fYear

2009

fDate

19-25 April 2009

Firstpage

1836

Lastpage

1844

Abstract

We design and implement Soft-TDMAC, a software Time Division Multiple Access (TDMA) based MAC protocol, running over commodity 802.11 hardware. Soft-TDMAC has a synchronization mechanism, which synchronizes all pairs of network clocks to within microseconds of each other. Building on pairwise synchronization, Soft-TDMAC achieves network wide synchronization. With, out-of-band, network wide synchronization Soft-TDMAC can schedule arbitrary TDMA transmission patterns. We summarize hundreds of hours of testing Soft-TDMAC on a multi-hop testbed. Our experimental results show that Soft-TDMAC synchronizes multi-hop networks to within a few microsecond sized TDMA slots. Soft-TDMAC can schedule transmissions to take end-to-end demands into account and in a way that decreases end-to-end delay. With no collisions, under good channel conditions, TCP achieves almost the full wireless channel bandwidth.

Keywords

synchronisation; time division multiple access; transport protocols; wireless LAN; wireless channels; MAC protocol; Soft-TDMAC; TCP; TDMA transmission patterns; commodity 802.11 hardware; end-to-end delay; multihop networks; multihop testbed; network clocks; network wide synchronization; pairwise synchronization; software TDMA-based MAC; software time division multiple access; synchronization mechanism; wireless channel bandwidth; Access protocols; Buildings; Clocks; Delay; Hardware; Media Access Protocol; Spread spectrum communication; Synchronization; Testing; Time division multiple access;

fLanguage

English

Publisher

ieee

Conference_Titel

INFOCOM 2009, IEEE

Conference_Location

Rio de Janeiro

ISSN

0743-166X

Print_ISBN

978-1-4244-3512-8

Electronic_ISBN

0743-166X

Type

conf

DOI

10.1109/INFCOM.2009.5062104

Filename

5062104