528 Chapter 16
W-CDMA Uplink Digital Modulation for Receiver Test
Compressed Mode Multiple Transmission Gap Pattern Sequence (TGPS) Overview
Compressed Mode Multiple Transmission Gap Pattern Sequence (TGPS)
Overview
Multiple TGPSs (pattern sequences) are used to sample frequencies from the various transmission formats
such as frequency division duplex (FDD), time division duplex (TDD), and GSM in preparation for a
handoff. The number of pattern sequences is dependent on the type(s) of transmission format you need to
sample. The following list shows the number of TGPSs that are required to receive each type of transmission
format:
FDD one TGPS per FDD frequency
TDD one TGPS per TDD signal
GSM three TGPSs per GSM signal
For example, if you wanted to sample the frequencies for a FDD and GSM signal, you would need four
TGPSs, one for the FDD signal and three for the GSM signal. If you wanted to sample three FDD
frequencies, you would need three TGPSs.
The ESG supports up to six different pattern sequences. Setting up the compressed frame signal with
multiple TGPSs is very similar to setting up a compressed frame signal using a single TGPS that is
demonstrated in the section “Configuring Compressed Mode” on page 521.
Each TGPS has the same parameters that are described in Table 16-3 on page 517, and the parameters are
local to each pattern sequence, with the exception of the PowOffs field. This field is common (global) for
all TGSPs and sets the amount of power offset for the compressed frames relative to the normal frames.
When it is set in one TGPS, it is applied to all the active pattern sequences and is shown in the PowOffs
field.
Understanding Multiple TGPS Compressed Frame Alignment
When multiple TGPSs are used, it is very important to ensure that there are no overlapping compressed
frames configured for the same frame position. If compressed frame overlapping occurs, the ESG
discontinues the compressed frame transmission (compressed frame start trigger is terminated) and normal
frames are transmitted. When the compressed frames from a multiple TGPS signal are properly aligned, the
output is a composite signal that contains the compressed frames from all the pattern sequences. Both
conditions are demonstrated in Figure 16-54.
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