Instruction manual

2-84
BreezeACCESS Version 4.3 Operations and Administration
Manual Revision: 4.0
different rates. The decision on the rate of each transmission (first
attempt) is based on counting transmissions, retransmissions and
successful windows. A window is defined as N consecutive
transmission or retransmission attempts, defined by the Multi-Rate
Decision Window Size parameter. A successful window is a window
in which the number of failed transmissions is not higher than a
defined threshold. A transmission is defined as failed if an ACK was
not received after the first transmission of a frame. If the current
rate is lower than the maximum available rate, the transmission
rate will be increased to the next available rate following a number
of successful windows. In order to minimize fluctuations, the
number of successful windows at a certain rate required to reach a
decision to increase the rate depends on previous rate of
unsuccessful windows at the higher rate. The higher the rate of
previous unsuccessful windows at a specific rate, the higher is the
number of required consecutive successful windows at the lower
rate prior to increasing the rate
. If the current rate is higher than the
minimum available rate (1 Mbps), the transmission rate will be
decreased to the next available rate following a failed window. The
Multi-Rate menu includes the following parameters:
 Multi-Rate Support – Enables or disables the Multi-Rate
decision algorithm. When enabled, the algorithm supports
increase/decrease of transmission rates in the range from
1 Mbps to the current value of the Maximum Data Rate
parameter. (Enabling the algorithm has no effect if the
Maximum Data Rate is 1 Mbps).
The default selection is Enable.
 Multi-Rate Decision Window Size – Sets the size of the
decision window. The size of a window is measured as the
number of consecutive transmission or retransmission
attempts. Increasing the size of the window will increase the
probability that it will be a successful window, thus slowing
down the decision to degrade to a lower rate and accelerating the
decision to upgrade to a higher rate.
Valid values are from 1 to 50.
The default value is 12.
 Number of Failures in Multi-Rate Decision Window – Sets the
maximum number of failures allowed in a decision window. A
window is defined as successful only if the number of failures is
not higher than this number. A transmission attempt is defined
as a failure if an ACK was not received upon the first
transmission attempt. Increasing the value of this parameter
will increase the probability that it will be a successful window,
thus slowing down the decision to degrade to a lower rate and
accelerating the decision to upgrade to a higher rate.
Valid value: 1 to Multi-Rate Decision Window Size.
Default value: 8.