Browse Prior Art Database

Efficient TDMA-Based Wireless LAN MAC Protocol for Latency Sensitive Traffic

IP.com Disclosure Number: IPCOM000114459D
Original Publication Date: 1994-Dec-01
Included in the Prior Art Database: 2005-Mar-28
Document File: 2 page(s) / 84K

Publishing Venue

IBM

Related People

Bauchot, F: AUTHOR [+3]

Abstract

Disclosed is a TDMA-based MAC protocol derived from the hybrid scheme presented in (*), which efficiently supports latency sensitive traffic patterns. The invention allows to get rid of the built-in latency which characterizes TDMA-based scheme.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Efficient TDMA-Based Wireless LAN MAC Protocol for Latency Sensitive
Traffic

      Disclosed is a TDMA-based MAC protocol derived from the hybrid
scheme presented in (*), which efficiently supports latency sensitive
traffic patterns.  The invention allows to get rid of the built-in
latency which characterizes TDMA-based scheme.

      In TDMA-based schemes, such as the one described in (*), the
traffic of each user is scheduled at the beginning of each time
frame.  Some piece of data ready to be transmitted cannot be
effectively transmitted if the scheduler has not assigned some time
interval to it.  This gap between the data readiness and the data
transmission translates into latency that may detrimentally affect
performances.  The presented scheme allows to decrease this effect by
allocating some time intervals thanks to a mechanism of traffic
anticipation.  Should this traffic occur, then the time interval can
be used without having to wait for the next time frame.  Should this
traffic not appear, then the time interval is lost.  To keep this
loss without performance impact, the traffic anticipation mechanism
is only performed during light load conditions.

      Let illustrate this generic concept in a typical embodiment,
corresponding to the protocol as described in (*).  The time scale
corresponds to a sequence of Time Frames (TF) of equal duration,
which are subdivided into three periods A, B and C.  They
respectively correspond to scheduled traffic from the Base Station
(BS) to the Mobile Stations (MSs), to scheduled traffic from the MSs
to the BS, and to unscheduled traffic from the MSs to the BS.  All
the A and B period traffic is scheduled at the beginning of each time
frame.  Assume now a traffic pattern corresponding to a sequence of
m...