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WCDMA Signaling
R&S
®
CMW-KG4xx/-KM4xx/-KS4xx
54
User Manual 1173.9657.02 ─ 11
Slot Trigger
Trigger event at the beginning of each downlink DPCH slot. If no downlink DPCH is
available, the trigger is aligned to the CPICH instead.
TPC Trigger
Trigger event one slot before a TPC pattern is sent to the UE via the downlink DPCH.
For details see
chapter 2.2.14.9, "Generating TPC Trigger Signals"
This trigger signal is only available when the downlink signal contains a DPCH.
UL Compressed Mode Trigger
The UL compressed mode trigger is derived from the beginning of each frame where a
transmission gap pattern begins, starting with the frame with the first transmission gap
pattern.
The "UL Compressed Mode Trigger" trigger signal is especially useful to trigger
WCDMA TPC measurements in "UL Compressed Mode" (option R&S CMW-KM400).
For this use case, configure a downlink RMC with loopback and select the TPC pattern
"TPC Test Step UL CM" and the compressed mode pattern "UL CM TX Test".
2.2.14 Transmit Power Control (TPC)
In CDMA networks, control of the UE transmit power is essential to ensure stable
transmission and an efficient radio resource management within the system. An output
power of the UE transmitter that is too low decreases the coverage area while an
excess output power may cause interference to other channels or systems. Both
effects decrease the system capacity.
The Node B transmits a series of Transmit Power Control (TPC) commands on the DL
DPCH. The UE receives the TPC commands and adjusts its transmit power according
to one of the following algorithms for uplink power control (see 3GPP TS 25.214):
●
Algorithm 1
:
One TPC command is received in each slot. If the received TPC command is equal
to 1 (0), then the power control parameter TPC_cmd for that slot is +1 (–1). This
implies that the UE transmitter output power changes after each slot.
●
Algorithm 2
:
One TPC command is received in each slot. The slots are grouped into sets of 5
slots, aligned to the frame boundaries, so that there is no overlap between different
sets of 5 slots.
If the received TPC command is equal to 1 (0) in all 5 slots of a set, then the power
control parameter TPC_cmd for the 5
th
slot is +1 (–1). Otherwise TPC_cmd for the
5
th
slot is 0. This implies that the UE transmitter output power only changes if the
same TPC command is received in a complete set of 5 slots.
For both algorithms, the UE transmitter output power changes by TPC_cmd multiplied
with the TPC step size of 1 dB or 2 dB. According to 3GPP, the TPC step size for Algo-
rithm 2 is always 1 dB. The step size for Algorithm 1 can be 1 dB or 2 dB.
General Description
深圳德标仪器
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