Analyzing protocol logs of Packet Switched Data
Last updated: December 3, 2008
This section is only applicable to the lab applications.
You can use the Wireless Protocol Advisor (WPA) to observe and analyze messages and information related to many aspects of packet switched data. This section contains some examples of how you can modify the WPA view to make it easier to access certain fields.
Your default WPA traffic overview column setup may look similar to Default WPA Traffic Overview .
One aspect of packet switched data is polling to ascertain if packets were received correctly. For GPRS, a supplementary/poll (S/P) bit is sent to a mobile station when an update on packets received correctly or incorrectly is desired. Another parameter related to this is the Relative Reserved Block Period (RRBP). For more information on this, see Relative Reserved Block Period (RRBP) . In the test set, when the BLER connection type is used, you can configure how often the test set polls the mobile station. (See Block Polling Parameters .
To more easily see the changes in the parameters mentioned above, you can add protocol field columns to the traffic overview (see WPA Traffic Overview with additional Protocol Field Columns ). If you add the RRBP Indicator field from the RLC_MAC layer, you can see the formula the mobile station uses to calculate when to send its response to a poll. Adding SPB, also from the RLC_MAC layer, allows you to see in which blocks the S/P has been set, and therefore when the RRBP is valid or not.
In the figure below, the block polling rate has been set to 4, meaning the test set polls the mobile station every 4 blocks. You can see that the SPB value is RRBP field is valid for every 4 downlink RLC data blocks.
Refer to the WPA Help for protocol field column configuration instructions. This is accessible from WPA by clicking the help button or for download at:
http://www.keysight.com/find/e6584a
