Intermec MobileLAN access WA21 System Manual page 117

MobileLAN access System Manual
Manual MAC Parameter Descriptions
Parameter Explanation
Hop Period Specifies how long the master radio stays on a frequency in the
(Master radio only)
hopping sequence before stepping to the next frequency. Longer
time periods result in better throughput while shorter time
periods result in faster roaming response and immunity from
interference. This parameter can be set to 100, 200, or 400 ms.
Beacon Frequency Specifies the number of hops between beacons (the access point
(Master radio only) periodically transmits a beacon to allow end devices to quickly
scan each frequency to find a master access point). You can set
this parameter to a value from 1 to 7.
Deferral Slot Works with the Fairness Slot parameter to determine the average
(Master radio only) back-off time when the channel is busy. You may want to reduce
the number of slots on lightly loaded networks to increase
throughput or increase the number of slots to help prevent
repeated collisions under a heavy load. You can set this
parameter to 1, 3, 7, or default.
Fairness Slot Works with the Deferral Slot parameter to determine the average
(Master radio only) back-off time when the channel is busy. You may want to
increase the number to prioritize the channel access for nodes
that have been waiting the longest to access the channel or you
may need to decrease the number to minimize initial back-off
delays. You can set this parameter to 1, 3, 7, or default.
Fragment Size Specifies the maximum fragment size that can be sent over the
radio during interference (fragments are created when errors
occur in transmission). You may want to set a smaller fragment
size if your environment has a high level of interference. You can
set this parameter to a value from 1 to 1540.
Transmit Mode Modulates the transmit signal and sets the bits per second.
AUTO automatically adapts the bit rate to the error conditions.
The transmit mode is automatically selected for the best range
and throughput.
BFSK (Binary Frequency Shift Keying) transmits at 0.8 Mbps.
Data is transmitted by shifting between two frequencies to
represent one bit of 0 or 1. BFSK has extended range over QFSK
at the expense of throughput.
QFSK (Quadrature Frequency Shift Keying) transmits at 1.6
Mbps. Data is transmitted by shifting among four frequencies to
represent two bits of 0 or 1. QFSK has better throughput than
BFSK at the expense of range.
Normal Ack Retry Controls the number of times an unfragmented frame is resent
unsuccessfully before fragmenting. You can set the parameter to
a value from 1 to 255. The default is 255, which allows the radio
to choose an optimal value.
The Norm Ack Retry count includes the Norm QFSK Retry
count; therefore, Norm Ack Retry should be greater than Norm
QFSK Retry.
Chapter 4 — Configuring the Radios
103