Requirements For The Cisco Unified Wireless Ip Phone 7925G; Site Survey; Rf Validation - Cisco 7925G Deployment Manual

Requirements for the Cisco Unified Wireless IP Phone 7925G

The Cisco Unified Wireless IP Phone 7925G is an IEEE 802.11a/b/g wireless IP phone that provides voice communications in
conjunction with these components. Check that your wireless LAN meets the requirements to support the specifications for
these phones:

Site Survey

Before deploying the Cisco Unified Wireless IP Phone 7925G into a production environment, a site survey must be completed
by a Cisco certified partner with the advanced wireless LAN specialization. During the site survey the RF spectrum can be
analyzed to determine which channels are usable in the desired band (2.4 GHz or 5 GHz). Typically there is less interference in
the 5 GHz band as well as more non-overlapping channels, so 5 GHz is the preferred band for operation. The site survey will
include heatmaps showing the intended coverage plan for the location. The site survey will also determine which access point
platform type, antenna type, access point configuration (channel and transmit power) to use at the location. See the
the Wireless LAN for Voice" section for more information.

RF Validation

In order to determine if VoWLAN can be deployed, the environment must be evaluated to ensure the following items meet
Cisco guidelines.
Signal
The cell edge should be designed to -67 dBm where there is a 20-30% overlap of adjacent access points at that signal level.
This ensures the 7925G phone always has adequate signal and can roam seamlessly.
Channel Utilization
Channel Utilization levels should be kept under 50%.
If using the 7925G phone, this is provided via the QoS Basic Service Set (QBSS), which equates to around 105.
Noise
Noise levels should not exceed -92 dBm, which allows for a Signal to Noise Ratio (SNR) of 25 dB where a -67 dBm signal should be
maintained.
Packet Loss / Delay
Per voice guidelines, packet loss should not exceed 1% packet loss, otherwise voice quality can be degraded significantly.
Jitter should be kept at a minimal (< 100 ms)
Retries
802.11 retransmissions should be less than 20%.
Multipath
Multipath should be kept to a minimal as this can create nulls and reduce signal levels.
Many different tools and applications can be used to evaluate these items in order to certify the deployment.
Cisco Spectrum Expert
AirMagnet (Survey , WiFi Analyzer, VoFi Analyzer, Spectrum Analyzer)
Cisco Wireless Control System (WCS) for Unified Wireless LAN management
Cisco Unified Wireless IP Phone 7925G Deployment Guide
"Designing
5