P-RS/MBMS Tab: Downlink Control Channel Properties

Menu Path: MeasSetup > LTE Demod Properties... > Profile tab > Edit Control Params... > P-RS/MBMS tab

In the Downlink Control Channel Properties dialog's P-RS/MBMS tab, you can set the parameters for the P-RS Positioning Reference Signal and MBSFN control channels.

P-RS

When the Active check box is selected, the LTE Long Term Evolution Demodulator will find and analyze the Positioning Reference Signal according to the following parameters.

Bandwidth (RBs)

Determines the frequency width of the P-RS in units of resource blocks. This frequency band is centered in frequency with respect to the LTE frame.

All possible P-RS bandwidths are available for selection, but if you select a P-RS bandwidth larger than the current LTE frame bandwidth, the P-RS bandwidth will be limited to the maximum possible once you click OK to close this dialog.

Power Boost

P-RS power boost (see description of Power Boost parameters in Basic tab topic) determines the power of P-RS relative to the 0 dB point of the LTE frame.

Config. Index

The Configuration Index specifies the value of I_PRS in the standard and is used to determine the periodicity and starting subframe of the P-RS from Table 6.10.4.3-1 in TS Technical Specification 36.211.

When the frame number is known (PBCH decoding enabled), the LTE demodulator can determine the exact frame/subframes that contain P-RS. In this case, the demodulator will expect P-RS in these frames and report bad EVM Error vector magnitude (EVM): A quality metric in digital communication systems. See the EVM metric in the Error Summary Table topic in each demodulator for more information on how EVM is calculated for that modulation format. when P-RS is not found. P-RS found in non-P-RS frames will also be reported as bad EVM.

When the frame number is not known (PBCH Physical Broadcast Channel decoding disabled), the LTE demodulator will search for P-RS in any potential P-RS subframes and analyze P-RS only when found.

N_PRS

Number of contiguous subframes allocated for P-RS.

Possible selections are N1, N2, N4, and N6 indicating 1, 2, 4, and 6 subframes, respectively.

Precoding

P-RS Precoding specifies if the signal's Positioning RS (PRS) resource elements have precoding applied. The parameter is available only if the number of antenna ports is 2.

Off (default) - PRS Precoding = Off

On - PRS Precoding = On

MBSFN

When the Active check box is selected, the LTE Demodulator will find and analyze MBMS Multimedia Broadcast Multicast Service signals (PMCH and MBSFN-RS) according to the following parameters.

Area ID

Specifies the value of N^MBSFN_ID which is used to determine the MBSFN-RS Multicast-Broadcast Single Frequency Network Reference Signal reference sequence.

Possible values are in the range 0-255.

Non-MBSFN region length

Specifies the number of symbols at the beginning of an MBSFN subframe that are not used for MBSFN transmissions.

Possible values are 1 or 2.

MBSFN-RS Power Boost (dB)

MBSFN-RS power boost (see description of Power Boost parameters in Basic tab topic) determines the power of MBSFN-RS relative to the 0 dB point of the LTE frame.

Subframe Config

Determines which subframes are possible MBSFN subframes. The behavior of MBSFN-RS analysis is different depending on whether RB Auto Detect is enabled.

RB Auto Detect selected: the LTE Demodulator will find and analyze any MBSFN signals in the selected subframes. When MBSFN is not present in a subframe, the demodulator will assume that the subframe is a non-MBSFN subframe.
RB Auto Detect cleared: the LTE Demodulator will expect MBSFN signals in only the specified subframes whose PMCH Present check box is selected as well.

PMCH

The PMCH Physical Multicast Channel section appears differently depending on whether RB Auto Detect is selected or not.

This parameter appears when RB Auto Detect is selected.

PMCH Power Boost: specifies the expected power of PMCH in autodetected MBSFN subframes, relative to the 0 dB point of the LTE signal (see description of Power Boost parameters in Basic tab topic).

These parameters are used to manually configure PMCH (RB Auto Detect is not selected) for the possible MBSFN subframes.

PMCH Present: indicates that PMCH (and correspondingly, MBSFN-RS) is present in a subframe.
Power Boost: specifies the power of PMCH in a subframe relative to the 0 dB point of the LTE signal (see description of Power Boost parameters in Basic tab topic).
Mod Type: specifies the modulation type for PMCH. Possible values are QPSK Quadrature phase shift keying, QAM16, and QAM64.