User's Manual Part 1
Release8PlanningGuide
Issue2,November2007 Draft5forRegulatoryReview 135
12.4 USINGLINKEFFICIENCYTOCHECKRECEIVEDSIGNALQUALITY
A link test, available in the Link Capacity Test tab of the Tools web page in an AP or BH,
provides a more reliable indication of received signal quality, particularly if you launch
tests of varying duration. However, a link test interrupts traffic and consumes system
capacity, so do not routinely launch link tests across your networks.
12.4.1 ComparingEfficiencyin1XOperationtoEfficiencyin2XOperation
Efficiency of at least 98 to 100% indicates a high quality signal. Check the signal quality
numerous times, at various times of day and on various days of the week (as you
checked the RF environment a variety of times by spectrum analysis before placing
radios in the area). Efficiency less than 90% in 1X operation or less than 60% in 2X
operation indicates a link with problems that require action.
12.4.2 WhentoSwitchfrom2Xto1XOperationBasedon60%LinkEfficiency
In the above latter case (60% in 2X operation), the link experiences worse latency (from
packet resends) than it would in 1X operation, but still greater capacity, if the link remains
stable at 60% Efficiency. Downlink Efficiency and Uplink Efficiency are measurements
produced by running a link test from either the SM or the AP. Examples of what action
should be taken based on Efficiency in 2X operation are provided in Table 30.
Table 30: Recommended courses of action based on Efficiency in 2X operation
Module Types Further Investigation Result Recommended Action
Advantage AP
with
Advantage SM
Check the General Status tab
of the Advantage SM.
1
See
Checking the Status of 2X
Operation
on Page 92.
Uplink and
downlink are both
≥60% Efficiency.
2
Rerun link tests.
Rerun link tests.
Uplink and
downlink are both
≥60% Efficiency.
Optionally, re-aim SM, add a
reflector, or otherwise mitigate
interference. In any case, continue
2X operation up and down.