Alvarion BreezeNET B System Manual page 145

Chapter 4 - Operation
delay) should take into account the round trip propagation delay between the two
units (the one-way propagation delay at 5 GHz is 3.3 microseconds per km / 5
microseconds per mile). The higher the distance between the BU and the RB, the
higher the acknowledge time delay used by both units should be. The ACK
timeout in microseconds is: 20+Distance (km)*2*3.3 or 20+Distance (miles)*2*5.
The distance between the BU and the RB can be determined either manually or
automatically. In manual mode, this distance is configured manually. In
automatic mode, the BU uses a special algorithm to estimate its distance from the
RB.
The Link Distance Parameters menu includes the following parameters:
4.2.6.2.10.1 Link Distance Mode
The Link Distance Mode option defines whether the distance between the BU and
the RB will be determined manually (using the Maximum Link Distance
parameter) or automatically.
The Options are Automatic or Manual.
The default is Automatic.
4.2.6.2.10.2 Maximum Link Distance
The Maximum Link Distance parameter allows configuring the distance between
the BU and the RB when the Link Distance Mode option is Manual.
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).
4.2.6.2.10.3 Fairness Factor
The Fairness Factor defines the effect of the Link Distance (calculated or
configured manually) on the slot size. In good quality links, the minimal slot size
(9 microseconds) can be used, providing maximum throughput. In a link with
poor conditions (such as a high interference level), the slot size should be
increased to enable better performance. The higher the Fairness Factor, the
higher is the impact of the Link Distance on the actual slot size.
The range is 0 to 100 (%)
The default is 100 (%), meaning maximum impact of the distance on the slot size.
BreezeNET B 121
Menus and Parameters
System Manual