Abstract:
The IEEE 802.11 wireless local area network (WLAN) standard, especially 802.11a re-
mains the most popular way to exchange data over wireless links. The major requirement
is to adapt to highly dynamic channel conditions with minimum overhead and ensure
robustness and speed of transmission. To this end, we propose a novel rate adaption
scheme NARC (Neighbor Aware Rate Control). Firstly, our key contributions include
exploiting the more precise channel estimation of SNR based rate adaptation coupled
with estimating the channel condition at the receiver and nally sending this estimated
information to the transmitter with minimum overhead. We use acknowledgment rates
to serve this feedback purpose. Our feedback mechanism also allows for optimal rate
switch rather than sequential one that most of the existing methods support. Secondly,
we address the stale feedback problem that the SNR based methods mainly su er from
and provide a unique solution to overcome this. To the best of our knowledge no works
have addressed the solution to this problem. The stale feedback problem was mitigated
by a prediction mechanism using linear regression on the observed rates on sender side
and feedback rates from the receiver side. Besides, we di erentiate the cause of frame
loss as either due to channel error or collision using RTS/CTS but in an adaptive fashion
to minimize overhead but at the same time ensure that rate is not falsely changed due
to frame loss caused by collision. NARC exploits the best of SNR based approaches and
provides channel condition at the receiver to the transmitter with minimum overhead
thereby ensuring optimal rate switching decision aided by sender side prediction mecha-
nism to tackle against stale feedback problem. Moreover use of Adaptive RTS provides
robustness to our method.
