Circuit Switched Data Service
Last updated: January 16, 2009
The test set supports two types of circuit switched (CS) data service:
The synchronous/transparent service is used by 3G-324M multi-media applications (for example, video phones), whereas the asynchronous/non-transparent service is used by more bursty data, such as IP traffic. The primary difference between the two services is that they use different radio bearer configurations, and the asynchronous/non-transparent configuration includes the RLP layer above the RLC entities (the RLC entities connect directly to the application in the synchronous/transparent configuration).
Asynchronous/Non-Transparent CS Data Service
The test set only supports UE-originated asynchronous/non-transparent CS data service, but both test set and UE-initiated release from the CS data service are supported.
Two radio bearers are supported: 57.6k UL/57.6k DL CS Data RAB (see 3GPP TS 34.108, 6.10.2.4.1.17) and 14.4k UL/14.4k DL CS Data RAB (see 3GPP TS 34.108, 6.10.2.4.1.15). You may specify the downlink DPCH channel codes for these two RABs using the
DPCH 120 ksps Channelization Code
and
DPCH 30 ksps Channelization Code
settings (see
Downlink Channel Codes and Levels
).
Async CS Data Source
You may choose what application protocol uses the CS data service using the
Async CS Data Source
setting. This setting can only be changed when the call status is idle. This setting allows you to specify the access point to the traffic plane data stream as follows:
-
Serial Port- connects the top of the L2R/RLP layer directly to the rear panel SERIAL 3 port of the test set. WhenAsync CS Data Sourceis set toSerial Port, debug access to the serial port is shut off, and the serial port is configured for CS data operation (data rate of 115,000 bps, 8 bits, no parity, 1 stop bit).
Software flow control (i.e. XON/XOFF characters) is used across the serial port to control the data flow. The L2R/RLP entity obeys the flow control commands from the UE and will similarly command the UE to stop sending data if its internal buffers begin to fill up. -
IP- connects the top of the L2R/RLP layer to a PPP/IP layer that is fed to the test set's LAN PORT . The PPP layer operates in asynchronous framing mode.
GPIB command: CALL:SERVice:CSData:MODE:ASYNchronous:OUTput .
Synchronous/Transparent CS Data Service
The synchronous/transparent CS data service allows you to make two types of 3G-324M video calls: UE-to-UE Video Call (lab application or feature-licensed test application) and UE-to-8960LAN Video Call (lab application only).
At this time, a video call connection is the only type of synchronous/transparent CS data service supported in the test set.
One radio bearer is supported: 64k UL/DL CS Data RAB (see 3GPP TS 34.108, 6.10.2.4.1.13). You may specify the downlink DPCH channel code for this RAB using the
DPCH 120 ksps Channelization Code
setting (see
Downlink Channel Codes and Levels
).