Force Code Group (TD-SCDMA)

Default: Downlink Pilot (See TD-SCDMA Standard Setups/Presets Table.)

The Force Code Group parameter selects a force code group of Downlink Pilot or Any Code. There are four Code IDs: Downlink Pilot, Uplink Pilot, Scramble, and Basic Midamble. These are described in Code/ID Allocation (TD-SCDMA Modulation Overview). The following is a chart of the code group interrelationships as specified in the standard 3GPP TS Technical Specification 25.2333 V5.3.0 Section 8.3:

$image\TD-SCDMAch_wmf.jpg$

When Downlink Pilot is selected, the Downlink Pilot Code ID determines the Code Group. When the Downlink Pilot Code ID is set, it forces the Uplink Pilot, Scramble and Basic Midamble code IDs into a consistent Code Group state (see chart above). The Uplink Pilot, Scramble and Basic Midamble code IDs can be adjusted by clearing the Code Group check box next to any of the other code groups. This will allow non-standard code ID sequence allocations.

When Any Code is selected, whichever Code ID is entered (Downlink Pilot, Uplink Pilot, Scramble or Basic Midamble) becomes the leader and the rest of the Code ID groups are forced into a consistent Code Group state (see chart). This option is convenient when the Basic Midamble Code ID or Scramble Code ID are known and the Pilot Code IDs are unimportant, as is often the case with uplink analysis.

When the Force Code Group is changed from Downlink Pilot to Any Code, the Code IDs will be forced into the same Code Group as the Basic Midamble Code ID.