Uplink parameters define configuration of the Physical Random Access Channel (PRACH) and the uplink Dedicated Physical Channel (DPCH). Uplink parameters are used during Active Cell operation, but many can only be changed during Cell Off mode operation, or while the call status is Idle, as indicated in the descriptions below.
To configure the uplink HS-DPCCH, used during HSDPA operation ( lab application or feature-licensed test application only ), see HSDPA Uplink Parameters .
The uplink Physical Random Access Channel (PRACH) carries the Random Access Channel (RACH) information which is transmitted by the UE during registrations or BS originated calls. A PRACH is composed of two parts: a number of preambles and a message portion. The preambles are a series of RF power "steps" which increase in power according to the power step setting until the maximum number of preambles is reached or the base station acknowledges receiving the preamble on the acquisition indication channel (AICH). Once the UE receives a positive indication on the AICH, it transmits the message portion of the PRACH which consists of message data and control data (pilot bit and TFCI) with independent power gain control.
PRACH power ramp step is used to increase the transmit power of the PRACH preamble when no response is received from the test set.
GPIB command: CALL:UPLink:PRAChannel:POWer[:RAMP]:STEP[:LEVel] .
This setting can only be changed when call status is
Idle
. If
BCCH Update Page
is set to
Auto
and you change this setting while your UE is camped to the test set, the test set performs a
Broadcast Channel (BCCH) Update Procedure (SIB Contents)
. If
BCCH Update Page
is set to
Inhibit
(the default value) and you change this setting while your UE is camped to the test set, you must force your UE to re-read the BCCH to observe the change (see
BCCH Update Page
for more details).
As specified in 3GPP TS 25.211 section 5.2.2.1.2, the PRACH preamble is of length 4096 chips and consists of 256 repetitions of a signature of length 16 chips. There are a maximum of 16 available signatures that the UE can use for its PRACH preamble. 3GPP TS 25.213 section 4.3.3.3 defines these 16 signatures, which are numbered from 0 to 15.
You may specify which of the 16 signatures are available to the UE. The UE may then choose any one signature for a PRACH preamble. As defined in 3GPP TS 25.331 section 10.3.6.52, a 16-bit mask is available to specify which of the 16 signatures are available to the UE (
PRACH Signatures, Upper (Bit Mask)
and
PRACH Signatures, Lower (Bit Mask)
from the front panel). Setting the upper-most bit of the mask to 1 indicates that signature 15 is available, setting the lower-most bit of the mask to 1 indicates that signature 0 is available. You may set any one or all of the bits in the mask to 1. For example, setting the mask to 0010001100100011 indicates that signatures 13, 9, 8, 5, 1 and 0 are available to the UE.
For the lab application only, the test set reports which signature is used by the UE on its final PRACH burst, see
Detected PRACH Signature
. If the
PRACH Signature
setting specifies a single PRACH signature, then
Detected PRACH Signature
and
PRACH Signature
should be the same.
For the lab application only, the PRACH preamble analysis measurement also reports the signature used by the UE for the PRACH burst it has analyzed (see
PRACH Preamble Analysis Measurement Description
). If the
PRACH Signature
setting specifies a single PRACH signature, then the PRACH signature reported by the measurement,
Detected PRACH Signature
and
PRACH Signature
should be the same.
GPIB command: CALL:UPLink:PRAChannel:SMASk .
This setting can only be changed when call status is
Idle
. If
BCCH Update Page
is set to
Auto
and you change this setting while your UE is camped to the test set, the test set performs a
Broadcast Channel (BCCH) Update Procedure (SIB Contents)
. If
BCCH Update Page
is set to
Inhibit
(the default value) and you change this setting while your UE is camped to the test set, you must force your UE to re-read the BCCH to observe the change (see
BCCH Update Page
for more details).
Scrambling code used to spread the Signature when creating a PRACH preamble.
GPIB command: CALL:UPLink:PRAChannel:SCODe .
This parameter can not be changed in active cell operating mode (use cell off operating mode).
This parameter selects whether the gain settings for the message portion of the PRACH are set manually or automatically by the test set. When
PRACH Bc/Bd Control
is set to
Auto
, Beta
c
and Beta
d
are both set to 15.
When
PRACH Bc/Bd Control
is set to
Manual
:
Used to specify the gain setting for the control data of the message portion of the PRACH (Beta c ).
GPIB command: CALL:UPLink:PRAChannel:MANual:CBETa .
Used to specify the gain setting for the message data of the message portion of the PRACH (Beta d ).
GPIB command: CALL:UPLink:PRAChannel:MANual:DBETa .
This setting can only be changed when call status is
Idle
. If
BCCH Update Page
is set to
Auto
and you change this setting while your UE is camped to the test set, the test set performs a
Broadcast Channel (BCCH) Update Procedure (SIB Contents)
. If
BCCH Update Page
is set to
Inhibit
(the default value) and you change this setting while your UE is camped to the test set, you must force your UE to re-read the BCCH to observe the change (see
BCCH Update Page
for more details).
GPIB commands: CALL:UPLink:PRAChannel:BETA:AUTo , CALL:STATus:PRAChannel[:CELL]:CURCbeta? and CALL:STATus:PRAChannel[:CELL]:CURDbeta? .
The
Uplink Timing Offset
allows you to specify the offset of the UE's PRACH transmission from the start of the access slot. The range is -256 to +256 chips.
For the lab application only, you can use the PRACH Preamble Analysis measurement to calculate your UE's offset (see Timing Error (in chips) ).
This parameter can not be changed in active cell operating mode (use cell off operating mode).
GPIB command: CALL:UPLink:PRAChannel:TIMing[:OFFSet]
Specifies the maximum number of preambles to be sent during one PRACH ramping cycle (see PRACH Ramping Cycles (MMAX) ) when no response is received from the test set. To prevent the test set from responding to the PRACH request, turn Call Limit State on.
GPIB command: CALL:UPLink:PRAChannel:PREambles:NUMBer .
This setting can only be changed when call status is
Idle
. If
BCCH Update Page
is set to
Auto
and you change this setting while your UE is camped to the test set, the test set performs a
Broadcast Channel (BCCH) Update Procedure (SIB Contents)
. If
BCCH Update Page
is set to
Inhibit
(the default value) and you change this setting while your UE is camped to the test set, you must force your UE to re-read the BCCH to observe the change (see
BCCH Update Page
for more details).
Specifies the maximum number of preamble sequences to be repeated when no response is received from the test set. To prevent the test set from responding to the PRACH request, turn Call Limit State on.
GPIB command: CALL:UPLink:PRAChannel:PREambles:RCYCles[:MMAX] .
This setting can only be changed when call status is
Idle
. If
BCCH Update Page
is set to
Auto
and you change this setting while your UE is camped to the test set, the test set performs a
Broadcast Channel (BCCH) Update Procedure (SIB Contents)
. If
BCCH Update Page
is set to
Inhibit
(the default value) and you change this setting while your UE is camped to the test set, you must force your UE to re-read the BCCH to observe the change (see
BCCH Update Page
for more details).
Specifies which of the twelve PRACH subchannels are available for UE PRACH access. The PRACH is divided up into 15 timeslots known as access slots. Each PRACH subchannel consists of a group of access slots. The more subchannels the UE is allowed to use, the more often it can transmit on the PRACH (see 3GPP TS 25.214 s6.1.1).
A setting of "1" indicates the corresponding subchannel is available, while a setting of "0" means the subchannel is unavailable. For example, a setting of "111111111111" means all twelve subchannels are available. A setting of "000000000001" means that only subchannel 0 is available. See 3GPP TS 25.331 s10.3.6.52.
GPIB command: CALL:UPLink:PRAChannel:ASUBchannels .
This setting can only be changed when call status is
Idle
. If
BCCH Update Page
is set to
Auto
and you change this setting while your UE is camped to the test set, the test set performs a
Broadcast Channel (BCCH) Update Procedure (SIB Contents)
. If
BCCH Update Page
is set to
Inhibit
(the default value) and you change this setting while your UE is camped to the test set, you must force your UE to re-read the BCCH to observe the change (see
BCCH Update Page
for more details).
The
Maximum Uplink Transmit Power Level
setting determines the value of the "Maximum allowed UL TX power" information element sent in SIB3 by the test set (see 3GPP TS 25.331 s8.6.6.8 and s10.3.6.39). Per 3GPP TS 25.331 s8.1.1.6.3-4, the UE shall use the contents of SIB3 while in idle mode. Thus, the UE must use the value of "Maximum allowed UL TX power" signalled in SIB3 to determine the maximum power at which it may transmit its PRACH (referred to as UE_TXPWR_MAX_RACH in 3GPP TS 25.304 and 25.331).
Note that when establishing a connection, the test set always sends a value of +33 dBm for the "Maximum allowed UL TX power" information element sent in the RRC Connection Setup message. Thus, the UE's maximum DPCH transmit power is always limited to +33 dBm, regardless of the
Maximum Uplink Transmit Power Level
setting.
Maximum Uplink Transmit Power Level
to the maximum transmit power for your UE. See
UE Does Not Camp to Test Set at Low Cell Power Levels
.3GPP TS 25.101 6.2.1 specifies the following maximum transmit powers per power class:
| Power Class | Maximum Transmit Power (dBm) |
|---|---|
| 1 | +33 |
| 2 | +27 |
| 3 | +24 |
| 4 | +21 |
Note that
Maximum Uplink Transmit Power Level
can be set to
+33 dBm
(for example, to ensure that your UE can properly process this value), but none of the test set's measurements are specified beyond +28 dBm.
To aid in successful call completion, ensure that your UE does not begin its PRACH preamble sequence at the
Maximum Uplink Transmit Power Level
or its maximum transmit power (see
Call Setup Fails Due to Transmission of Single PRACH Preamble
).
GPIB command: CALL:UPLink:TXPower:LEVel:MAXimum .
This setting can only be changed when call status is
Idle
. If
BCCH Update Page
is set to
Auto
and you change this setting while your UE is camped to the test set, the test set performs a
Broadcast Channel (BCCH) Update Procedure (SIB Contents)
. If
BCCH Update Page
is set to
Inhibit
(the default value) and you change this setting while your UE is camped to the test set, you must force your UE to re-read the BCCH to observe the change (see
BCCH Update Page
for more details).
The uplink Dedicated Physical Channel (DPCH) consists of the Dedicated Physical Data Channel (DPDCH) which carries the user data, and the Dedicated Physical Control Channel (DPCCH) which carries the physical layer control information (pilot data, TFCI and TPC).
Scrambling code used to provide a unique channelization required for each UE.
GPIB command: CALL:UPLink:DPCHannel:SCODe .
This setting can only be changed while in
Cell Off
or
FDD Test Operating Mode
.
This parameter selects whether the DPCH gain settings are set manually or automatically by the test set. When
Uplink DPCH Bc/Bd Control
is set to
Auto
, the gain settings are automatically set by the test set.
For example, for a 12.2k RMC, 3GPP TS 34.121 sC.2.1 specifies a DPCCH/DPDCH power ratio of -5.46 dB. A DPCCH/DPDCH power ratio of -5.46 dB is achieved if the amplitude ratio B c /B d is 8/15:
DPCCH/DPDCH power ratio = 20log 10 (B c /B d ) = -5.46 dB --> B c /B d = 0.5333 = 8/15
Thus, if
Channel Type
is set to an RMC including a 12.2k uplink and
Uplink DPCH Bc/Bd Control
is set to
Auto
, the test set automatically sets B
c
to 8 (8/15) and B
d
to 15 (15/15).
The following table specifies the settings used for each downlink channel type when
Uplink DPCH Bc/Bd Control
is set to
Auto
.
When
Manual
is selected, the following two settings are available:
Used to specify the gain setting for the DPCCH (beta c ). Range is 1 to 15 (see 3GPP TS 25.213 s4.2.1.1 Table 1 for a mapping of the signalled values to the resulting quantized amplitude ratios).
GPIB command: CALL:UPLink:DPCHannel:MANual:CBETa .
Used to specify the gain setting for the DPDCH (beta d ). Range is 0 to 15 (see 3GPP TS 25.213 s4.2.1.1 Table 1 for a mapping of the signalled values to the resulting quantized amplitude ratios).
GPIB command: CALL:UPLink:DPCHannel:MANual:DBETa .
Note that according to 3GPP TS 25.213 s4.2.1.1, "At every instant in time, at least one of the values Beta c and Beta d has the amplitude 1.0" (which corresponds to a signalling value of 15). However, the test set does not constrain you in this way; you may set Manual Uplink DPCH Bc to any value between 1 and 15 and independently set Manual Uplink DPCH Bd to any value between 0 and 15. Note that configuring Bc and Bd such that neither is set to 15 is undefined in the standards, and may result in unexpected behavior.
Also note that according to 3GPP TS 25.213 s4.2.1.1 Table 1, if Beta c or Beta d is signalled as 0, the DPCCH or DPDCH (respectively) is switched off.
These parameters cannot be changed in active cell operating mode. You must switch to cell off or FDD test operating mode to change these parameters. To change the gain settings signalled to the UE while in active cell operating mode, you must perform a Transport Channel Reconfiguration or Radio Bearer Reconfiguration .
You can query the beta c and beta d values currently being signalled to the UE by the test set using the CALL:STATus:DPCHannel[:CELL]:CURCbeta? and CALL:STATus:DPCHannel[:CELL]:CURDbeta? commands.
GPIB command: CALL:UPLink:DPCHannel:BETA:AUTo