Cisco Mesh Access Points Deployment Manual page 93

Site Preparation and Planning
Parameter
Tx Antenna Gain
Tx Beam Forming (BF)
Tx EIRP
Rx Antenna Gain
Rx Antenna Cable Loss
Rx Sensitivity
System Gain
Fade Margin
Range between APs
(LOS, PLE = 2.3)
The AP1552 models with built-in antennas (1552C/I) have the same system gain as AP1522s for 5-GHz
backhaul giving the AP to AP distance of 2722 feet. A fade margin of 9 dB is assumed, which is inconsistent
with the assumption to calculate the required SNR values in the Wireless Mesh Constraints section.
Link Budget Analysis for AP to Client ( A Domain)
This section contains a link budget analysis for the AP to the Client, so that you know how far away a client
can go from the AP with a system gain value in each band. In this analysis, the focus is on the system gain
for upstream and downstream. A link should be balanced for upstream and downstream, but it might not
happen. Generally, there is a higher antenna gain and higher Tx power available on the AP rather than on the
client. But, this can also be opposite in a few regulatory domains because of different EIRP limit requirements.
Therefore, the lowest of both upstream and downstream should be taken to calculate the AP to the client
distance because that will be the decision factor. For example, if there is a higher downstream gain than
upstream, the upstream should be the decision maker for the cell size because the upstream system gain allows
only the client to connect to the AP.
The regulatory domain values of Tx EIRP and Rx sensitivities decide whether upstream or downstream has
the lower system gain. The cell size should be determined by upstream and not downstream.
Because most of the clients available are 2.4-GHz clients, the focus is on the 2.4-GHz AP to the.
For the AP to client link budget in 2.4 GHz, let us assume a client Tx power of 20 dB and an antenna gain of
0 dBi (see
For the –A domain EIRP limit is 36 dBm for 2.4- and 5-GHz bands.
.
OL-27593-01
Cisco 1552 I/C
4 dBi (inbuilt antenna)
4 dB
36 dBm
4 dBi
0 dB
–91 dBm at 9 Mbps
131 dB
9 dB
829 meters (2722 feet)
Table 22: Outdoor 11n AP-to-Client, at 2.4 GHz: 9 Mbps Data Rate (–A domain), on page
Cisco Mesh Access Points, Design and Deployment Guide, Release 7.3
Cell Planning and Distance
Cisco 1552 E/H Cisco 1522
7 dBI 8 dBi
4 dB 0 dB
36.5 dBm 35.5 dBm
7 dBI 8 dBi
0.5 dB 0.5 dB
–91 dBm at 9 Mbps –88 dBm at 9 Mbps
134 dB 131 dB
9 dB 9 dB
1120 meters (3675 feet) 829 meters (2722 feet)
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