Alvarion BreezeACCESS EZ AU-EZ, Системное руководство

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Chapter 4 - Operation and Administration Menus and Parameters
BreezeACCESS EZ AU-EZ 82 System Manual
The default value depends on unit type. The default value for AUs that are
supplied with a detached antenna is in accordance with the antenna's gain. In
units supplied without an antenna the default is typically "Not Set Yet".
4.2.6.2.7 Cell Distance Parameters
The higher the distance of an SU from the AU that is serving it, the higher the time
it takes for messages sent by one of them to reach the other. To ensure
appropriate services to all SUs regardless of their distance from the AU while
maintaining a high overall performance level, two parameters should be adapted
to the distances of SUs from the serving AU:

The time that a unit waits for a response message before retransmission (ACK
timeout) should take into account the round trip propagation delay between
the AU and the SU (The one-way propagation delay at 5 GHz is 3.3
microseconds per km/5 microseconds per mile.). The higher the distance from
the AU of the SU served by it, the higher the ACK timeout should be.
The ACK timeout in microseconds is: 20+Distance (km)*2*3.3 or 20+Distance
(miles)*2*5.

To ensure fairness in the contention back-off algorithm between SUs located at
different distances from the AU, the size of the time slot should also take into
account the one-way propagation delay. The size of the time slot of all units in
the cell should be proportional to the distance from the AU of the farthest SU
served by it.
4.2.6.2.7.1 Maximum Distance
The Maximum Cell Distance parameter should be configured with the estimated
distance of the farthest SU served by the AU.
The range is 0 to 54 (Km). The value of 0 has a special meaning for No
Compensation: Acknowledge Time Out is set to a value representing the
maximum distance of 54 km. The time slot size is set to its minimal value of 9
microseconds.
The default is 0 (No Compensation).
4.2.6.2.7.2 Show Cell Distance Parameters
Select Show Cell Distance Parameters to view the Maximum Cell Distance
measured (not measured for SU-EZ units).
4.2.6.2.8 Arbitration Inter-Frame Spacing (AIFS)
The time interval between two consecutive transmissions of frames is called
Inter-Frame Spacing (IFS). This is the time during which the unit determines