Last updated: November 7, 2012
The
Active Cell Operating Mode allows you to make a signalling
connection between the test set (emulating a base station (BS)
in a network) and a UE (mobile station). The types of connections
available are described in Current Service Type
. When connected (and during the connection process for some measurements),
the UE's performance can be measured using the suite of measurements
shown when the Measurement selection key
or Instrument selection key is pressed.
The following
example selects Active Cell Operating
Mode via GPIB:
OUTPUT 714;"CALL:OPERating:MODE CALL"
You can configure the test set's base station emulator using the parameters described in Base Station Emulator Configuration .
While operating
in Active Cell mode the test
set is capable of performing many call processing operations (such
as Performing
a Location Update (CS Domain Registration) , Establishing
a Connection with the UE , and Handovers
) as described in Call Processing Status and
Operations .
Many of the settings
used in active cell mode cannot be changed during active cell mode operation.
A message is displayed to alert you to this situation if you try
to change them. These are settings that must be set before attempting
to get the UE connected on a call, or settings that are not normally
changed during base station operation in a network. Use the Cell Off operating mode to change
these settings. See CALL:OPERating to select
operating modes.
This section is only applicable to the lab application or feature-licensed test application.
In active cell operating mode, HSDPA is active when HS-SCCHs are being generated by the test set (even if HSDPA Cell 1 Connected HS-SCCH 1 Level is turned off). HS-SCCHs are created when an RB Setup message is sent to the UE as part of a service setup that includes an HSDPA channel configuration.
In active cell operating mode, you can establish two types of HSDPA connections:
When on an HSDPA RB Test Mode connection, in addition to the 12.2k RMC and common channels, the test set transmits HS-PDSCHs (the number is determined by the FRC Type or User Defined Number of Active HS-PDSCHs settings). When on an HSDPA Packet Data connection ( lab application only ), in addition to the common channels, the test set transmits HS-PDSCHs (the number is determined by the PS Data HS-DSCH Configuration Type setting and the Current UE HS-DSCH Category ).
The test set can transmit up to 4 HS-SCCHs (you directly specify how many HS-SCCHs you want the test set to transmit using the HSDPA Connected DL Channel Levels ). However, HS-SCCH 1 is the only HS-SCCH ever directed to the UE (see H-RNTI Parameters ).
When HSDPA is active, the test set also generates a six-channel OCNS as specified by 3GPP TS 34.121 sE.5.2 (codes 122 - 127, spreading factor 128), rather than the OCNS defined in sE.3.6 (see OCNS in HSDPA/HSPA ).
You can configure the downlink code channel levels and channelization codes that are used when HSDPA is active using the HSDPA/HSPA DL Channel Codes and HSDPA Connected DL Channel Levels .
You can configure
many aspects of the HSDPA functionality using the
HSDPA Parameters :
The HSDPA Information screen displays UE HS-DSCH category information as well as counters to help you monitor the HSDPA connection status.
You can vary the timing between the uplink DPCH and uplink HS-DPCCH using the Default DPCH Offset (DOFF) parameter.
This section is only applicable to the lab application or feature-licensed test application.
When on an HSPA RB Test Mode connection or HSPA PS Data connection, in addition to the 12.2k RMC and common channels the test set transmits HSDPA channels (HS-PDSCHs and HS-SCCHs) and HSUPA channels (E-HICH, E-AGCH, and E-RGCH). The test set also generates the same six-channel OCNS used for HSDPA connections (3GPP TS 34.121 sE.5.2).
You can configure the downlink code channel levels and channelization codes that are used when HSPA is active using the HSDPA/HSPA DL Channel Codes and HSPA Connected DL Channel Levels .
You can configure many aspects of the HSPA functionality using the HSUPA Parameters :
The HSUPA Information and HSUPA Happy Bit Information screen displays UE reported E-DCH category, counters to help you monitor the HSUPA connection status, as well as other HSUPA status indicators.
The test set supports UE E-DCH categories 1 to 7 and either 10 ms or 2 ms TTI.
The following call processing procedures are supported while on an HSPA RB Test Mode or HSPA PS Data connection.
| Call Processing Procedures | Supported for HSPA RB Test Mode connections | Supported for HSPA PS Data Connections |
|---|---|---|
| Physical Channel Reconfiguration | Yes | Yes |
| Transport Channel Reconfiguration | Yes | No |
| System Handover | Yes | No |
| Radio Bearer Reconfiguration | Yes | No |
| Intra-frequency UE Reported Measurements | Yes* | Yes* |
| Inter-RAT Handovers (See Two-Cell Test System and E-UTRAN / WCDMA Interworking ) | Yes | |
| Compressed Mode | Yes | Yes |
| * Soft Handover is supported for HSUPA connections but only to simulate a network scenario for when a UE performs a soft handover with cell 2 but the HSUPA channels remain confined to cell 1 (serving cell). | ||
E-AGCH:
While on an HSPA connection the test set transmits an E-AGCH.
A real network only transmits on the E-AGCH when it wants to send
a new absolute grant to a UE; if it has nothing to send, there
is no power in the E-AGCH. To keep OCNS power constant in the
test set (as required by many test specifications), the test set
continuously transmits the E-AGCH. When it wants to send an absolute
grant to the UE, it transmits the E-AGCH using the Primary E-RNTI (Hex) . When the test set is not
transmitting an absolute grant to the UE, it transmits the E-AGCH
using the Alternate
E-RNTI (Hex) . When transmitting using the
Alternate E-RNTI , the test set always sends an Absolute
Grant Value of 15 and an Absolute Grant Scope of "All HARQ
Processes".
E-HICH/E-RGCH: In a real network, DTX is used on the E-HICH and E-RGCH channels in some circumstances. However to keep OCNS power constant in the test set, DTX is not used. In the following circumstances the network would DTX the entire E-HICH or E-RGCH frame:
Information is signaled to the UE on the E-RGCH and E-HICH channels using a 40 bit orthogonal signature that can be completely transmitted in a single timeslot. There are 40 different signatures available to the network (see 3GPP TS 25.211 s5.3.2.4 Table 16A) and the two channels use a different signature in any given slot. This way both the E-RGCH and E-HICH can share the same channelization code. Rather than use a single static signature for a channel, the network hops between 3 different signatures. The UE knows which signature to expect for each channel in any given slot from a signature index it is assigned at call setup and its knowledge of the signature hopping pattern defined in 3GPP TS 25.211 s5.3.2.4 Table 16B. The UE is given a different signature index for the E-HICH and E-RGCH to ensure the two channels remain orthogonal. 3GPP TS 25.212 s4.11 & 4.12 define the mapping from logical value (for example ack or nack), to a specific numeric value that is then multiplied with the signature. For instance, on the E-HICH transmitted from a serving cell, an ack is signalled by a 1 and a nack by a -1. These values are then multiplied with the 40 bit orthogonal signature, which means an ack is signaled by the presence of the expected signature and a nack by the presence of the inverse of the expected signature. From the perspective of the UE listening to these channels, DTX is detected by the absence of the 40 bit orthogonal signature that it was expecting (inverted or non-inverted). However, because the signatures are all orthogonal to each other it is possible for the network to transmit a signature that the UE is not expecting and the UE will still detect DTX. This explains why the E-HICH/E-RGCH can utilize the same code channel. As long as the two channels are assigned different signature indices in the UE they remain orthogonal to each other despite occupying the same space in the OVSF code tree. A network also utilizes the orthogonal property of the signatures to multiplex multiple UEs onto the same E-HICH/E-RGCH code, again by assigning different UEs unique signature indices. Therefore in all the whole-frame DTX situations outlined above, the test set communicates DTX by transmitting a signature that the UE is not expecting (Alternate E-HICH Signature Sequence of 2), Alternate E-RGCH Signature Sequence of 3). This keeps the power in the E-HICH and E-RGCH constant, and thus OCNS remains constant, while still giving the test set the ability to signal DTX to the UE. The other situation where a real network will use DTX is in slots 13-15 of the E-HICH and E-RGCH. Both the E-HICH and E-RGCH (if the E-RGCH is being generated from a serving cell), are defined to transmit only during the first 12 slots of the 15-slot frame when 10ms TTIs are used. However, to keep the power in the E-HICH and E-RGCH constant, the test set transmits during slots 13-15 using the signatures defined in 3GPP TS 25.211 s5.3.2.4 Table 16B "E-HICH and E-RGCH signature hopping pattern". The same signature hopping index that is used for slots 1-12 is used for slots 13-15.