Below is the Predictive Site Survey report that I did for one of the of my clients in Ontario
1 Introduction
The purpose of this document is to determine the proper placement of Aruba wireless access points (AP) at the ABCD Hospital, 1234 Street location.
This document contains specific information such as site information, required coverage zone, service classes required, RF spectrum results, channel and power assignment and recommendations.
2. Customer coverage requirements
The ABCD Hospital wants wireless coverage everywhere at 1234 Street location except elevators, washrooms, staircases, rear desk, room 18, 19, 21 and south west. The service class of this wireless coverage is classified as “Voice” which means a signal strength of -65 dBm or greater everywhere, not supporting capacity. The intended use of the 802.11 a/b/g wireless network is for data and voice applications.
3. Capacity Requirement
Device load is based on an internal device model shown in Table below, which shows the total population of wireless devices to be supported. Capacity analysis is also performed using the capacity heatmaps of Ekahau. Access points are added to the basic coverage design until the capacity heatmap indicates adequate capacity.
4. Required coverage zones
The wireless coverage area is outlined in Blue as per diagram below.
5. Access points positioning
This section presents the recommended positioning of access points.
AP # 1 TOR-1234-ST-AP101
AP # 2 TOR-1234-ST-AP102
AP # 3 TOR-1234-ST-AP103
AP # 4 TOR-1234-ST-AP104
6. Coverage result – 2.4GHz
This section presents the coverage results on the 2.4GHz band.
It should be noted that following the installation, the coverage results may vary. The exit survey following the installation will identify these minor changes.
Signal strength 2.4GHz (dBm)
The signal strength is the strength of a signal from an access point in a specific location. A strong signal is required to prevent the attenuation and propagation effects. Furthermore, the transmission rate is enhanced with high signal strength. Signal strength must be at least at -65 dBm for voice applications.
Signal-to-Noise Ratio 2.4GHz (dB)
The signal-to-noise ratio is a representation of the quality of the signal being received by the mobile device. The lower the SNR value the less likely the data will be received and understood. That, in turn, will cause an increase in packet loss and retransmission leading to poor network performance. An acceptable SNR for voice communication is ≥20dB.
Data rate 2.4GHz (Mbps)
Data Rate values in 802.11 networks is a term used to describe the theoretical throughput available between the user and the AP. As the user moves further from the AP the available throughput will decrease. As described above for Signal and SNR values, throughput can only be achieved if sufficient signal is available (Signal) and sufficient quality is attainable (SNR). To ensure that sufficient capacity is available within the coverage area, the survey has been conducted to provide the best throughput available. This is accomplished by overlapping cells utilizing the available non-overlapping channels.
7. Coverage Result – 5GHz
This section presents the coverage results on the 5GHz band.
It should be noted that following the installation, the coverage results may vary. The exit survey following the installation will overcome these minor changes.
Signal strength 5GHz (dBm)
The signal strength is the strength of a signal from an access point in a specific location. A strong signal is required to prevent the attenuation and propagation effects. Furthermore, the transmission rate is enhanced with high signal strength. Signal strength must be at least at -65 dBm for voice applications.
Signal-to-Noise Ratio 5GHz (dB)
The signal-to-noise ratio is a representation of the quality of the signal being received by the mobile device. The lower the SNR value the less likely the data will be received and understood. That, in turn, will cause an increase in packet loss and retransmission leading to poor network performance. An acceptable SNR for voice communication is ≥20dB.
Data rate 5 GHz (Mbps)
Data Rate values in 802.11 networks is a term used to describe the theoretical throughput available between the user and the AP. As the user moves further from the AP the available throughput will decrease. As described above for Signal and SNR values, throughput can only be achieved if sufficient signal is available (Signal) and sufficient quality is attainable (SNR). To ensure that sufficient capacity is available within the coverage area, the survey has been conducted to provide the best throughput available. This is accomplished by overlapping cells utilizing the available non-overlapping channels.
8. Power and channel assignment
This section presents the channels (2.4GHz and 5GHz) and power levels that need to be configured on the access points.
Access Point Channel Channel Power
2.4GHz 5GHz Both Channels
AP # 1 TOR-1234-ST-AP101 1 36 25 mW (14 dBm)
AP # 2 TOR-1234-ST-AP102 1 52 25 mW (14 dBm)
AP # 3 TOR-1234-ST-AP103 11 44 25 mW (14 dBm)
AP # 4 TOR-1234-ST-AP104 6 149 25 mW (14 dBm)
9. Exit Survey Analysis
Methodology
The exit surveys are conducted using Ekahau Site Survey and follow industry best practices. The surveys capture signal strength (for coverage), signal-to-noise ratio, discovered AP placement and Capacity Health. The results are documented in this report to permit easy comparison to the predicted results in the design report.
Access points installed as per the original design are shown in green. Meanwhile, access points not in the original design but discovered by the survey are not shown for clarity considerations. Discovered access points estimated to be on other floors are moved to the side of the Ekahau plots in order to reduce clutter.
10. Exit Survey
Survey Path
The discovered access points are shown in Figure below along with the survey path. All new APs were discovered in their correct position.
Received Signal Strength Heat Map
The received signal strength heat map is shown for the 2.4 GHz band in the next picture. The heat map shows good coverage for all in-scope areas.
The received signal strength heat map is shown below for the 5GHz band The heat map shows good coverage for all surveyed areas.
Signal to Noise Ratio
The received signal strength heat map is shown for the 2.4 GHz band
Capacity Health Heat Map
The capacity health heatmap is shown next. The heatmap shows good capacity for all in-scope areas.
