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Site Survey Tool - TamoGraph

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Introduction
Overview
System Requirements
Driver Installation
Licensing and Trial Version Limitations
Interface Overview
Access Point List
Floor Plan / Site Map
Plans and Surveys, Properties, and Options Panel
Main Menu
Performing a Site Survey
New Project Wizard
Calibration
Configuration
Data Collection
Understanding Survey Types: Passive, Active, and Predictive
Active Survey Configuration
Best Practices, Tips, and Tricks
Survey Job Splitting
Predictive Surveys
Drawing Walls and Other Obstructions
Drawing Attenuation Zones
Placing and Configuring Virtual APs
Working with Presets
Applying Visualizations
Working with Multi-floor Sites
Mixing Real and Virtual Data
Best Practices, Tips, and Tricks
Analyzing Data – Passive and Predictive Surveys
Selecting Data for Analysis
Adjusting AP Locations After Passive Surveys
Splitting an AP into Multiple Unique APs
Working with Multi-SSID APs
Visualization Types
Signal Level
Signal-to-Noise Ratio
Signal-to-Interference Ratio
AP Coverage Areas
Number of APs
Expected PHY Rate
Frame Format
Channel Bandwidth
Channel Map
Requirements
Analyzing Data – Active Surveys
Selecting Data for Analysis
Visualization Types
Actual PHY Rate
TCP Upstream and Downstream Rate
UDP Upstream and Downstream Rate
UDP Upstream and Downstream Loss
Round-trip Time
Associated AP
Requirements
Spectrum Analysis
Hardware Requirements
Spectrum Data Graphs
Performing Spectrum Analysis Surveys
Viewing Collected Spectrum Data
Exporting Spectrum Data
Reporting and Printing
Customizing Reports
Google Earth Integration
Configuring TamoGraph
Plans and Surveys
Properties
Plan / Map
Environment
Client Capabilities
Requirements
Scanner
Options
Colors and Value Ranges
AP Detection and Placement
Visualization Settings
Miscellaneous
Configuring GPS Receiver
Using GPS Configuration Dialog
Finding the GPS Receiver Port Number
Taking Photographs
Voice Control
Using TamoGraph in a Virtual Machine
Frequently Asked Questions
Sales and Support

Expected PHY Rate

The physical layer (PHY) rate is the speed at which client devices communicate with the AP. When you move a computer connected to the AP within the WLAN coverage area, the adapter properties dialog in Windows displays the varying connection speed, which may be as high as 450 or 300 Mbps when you are close to the AP or as low as 1 Mbps when you are 50 meters away from it. The displayed speed is the PHY rate.

The PHY rate directly affects the throughput rate, which is the average speed at which the client and AP can exchange application-level data, such as files. The throughput rate is always lower than the PHY rate, typically by more than 50%, due to a number of factors, such as protocol overheads and retransmissions. A low PHY rate always means low data throughput and therefore poor WLAN performance.


When calculating PHY rates, TamoGraph uses the Client Capabilities settings that might or might not be as good as the AP capabilities. If the adapter's capabilities are inferior (e.g., if an 802.11n adapter is connected to an 802.11an AP), then the maximum PHY rate that the AP supports will not be reached. Please refer to the description of Client Capabilities for more information.

The PHY rate is shown for the AP that has the strongest signal in the given map area among the APs selected for analysis. This mimics the roaming behavior of client adapters that connected to the strongest AP. While other audible APs may offer higher PHY rates, a typical adapter will connect to the AP with the strongest signal. You can deselect one or several of the selected APs to see PHY rate values for less strong APs.

Expected PHY rate calculations are based on signal strength and use a table that maps signal levels to PHY data rates. The table uses average values for common adapter types. The actual PHY rate that you observe may be lower or higher than the expected rate, depending on the specific adapter and AP equipment being used.

Double-clicking on the Expected PHY rate legend on the status bar allows you to configure the color scheme.

Suggested Solutions

When low expected PHY rate areas are discovered, the following solutions are suggested:

· Increase the signal level, as it is directly related to the PHY rate. See the suggested solutions for increasing signal level in the Signal Level chapter.
· Check your AP capabilities. If you are using newer 802.11n equipment, make sure that the maximum MCS indices, Short GI, and 40 MHz channel bandwidth are allowed in the device configuration.
· Check your Client Capabilities settings. You might have erroneously limited them too much.
· If you are using legacy 802.11 a/b/g equipment, consider upgrading to 802.11n or 802.11ac.