Downlink Corruption

Downlink Corruption

Last updated: January 18, 2010

This section is only applicable to the GPRS and EGPRS lab applications.

In order to stress the mobile station's receiver and force the use of incremental redundancy and retransmission MCS switching, the downlink corruption feature allows you to specify the corruption of some downlink GPRS and EGPRS PDTCH blocks. Corrupting the downlink data will cause data retransmissions and will therefore cause bad BER and BLER results as well as cause deterioration in the IP data throughput.

Downlink Corruption Parameters

Parameter GPIB Command
Downlink Corruption State CALL:(PDTCH|PDTChannel):DOWNlink:CORRuption[:STATe]
Sequence Length CALL:(PDTCH|PDTChannel):DOWNlink:CORRuption:SEQuence:LENGth
Blocks in Sequence to Corrupt CALL:(PDTCH|PDTChannel):DOWNlink:CORRuption:SEQuence:CBURsts
Corruption applied to Burst [n] CALL:(PDTCH|PDTChannel):DOWNlink:CORRuption:BURSt<[1]|2|3|4>[:STATe]
First Corrupted Symbol CALL:(PDTCH|PDTChannel):DOWNlink:CORRuption:SYMBol:STARt
Number of Symbols to Corrupt CALL:(PDTCH|PDTChannel):DOWNlink:CORRuption:SYMBol:LENGth
Corruption Pattern CALL:(PDTCH|PDTChannel):DOWNlink:CORRuption:PATTern
Corrupt Signaling Blocks CALL:(PDTCH|PDTChannel):DOWNlink:CORRuption:SIGNaling

Setting the Number of Symbols to Corrupt parameter to a value greater than or equal to the Sequence Length, forces all blocks to be corrupted.

If you enter a value for either Number of Symbols to Corrupt or First Corrupted Symbol that would cause the corruption to exceed symbol number 147, the test set changes the last of those values you entered to a value making the total of the two parameters equal to 147.

There is no link between the blocks to be corrupted and the Block Sequence Number (BSN).

The corruption sequence is restarted when the Downlink Corruption State is set to On.

Operating Considerations

Downlink corruption can only be used in the following operating modes:

Changes can be made to Downlink Corruption in other operating modes, but there is no effect the test set's operation until the operating mode is a valid one.

Downlink Corruption is applicable to all the connection types.

Related Topics

How to Setup Corruption of Downlink Blocks

Incremental Redundancy

Retransmission MCS Switching