About DL Decode Info (LTE-Advanced)
PBCH Physical Broadcast Channel, PDCCH Physical Downlink Control Channel, PHICH Physical Hybrid ARQ Indicator Channel, and PCFICH Physical Control Format Indicator Channel.
contains the decoded information fromThe upper section shows the status of the PBCH, PDCCH, PCFICH, and PDSCH Physical Downlink Shared Channel decoders (On or Off).
The lower part of the table shows the decoded information for each frame.
The data is color coded to match the color of the corresponding channel in the Frame Summary trace. For example, any text that is colored green represents information about PBCH.
The screenshot below shows the decoded data for two frames.
PHICH information
The decoded PHICH Hybrid-ARQ Automatic Repeat Request 1) A distinct unit of data that is carried on an ARQ-enabled connection. Such a unit is assigned a sequence number, and is managed as a distinct entity by the ARQ state machines. Block size is a parameter negotiated during connection establishment. 2) automatic retransmission request - A signal used in digital communications systems used to signal the transmitting device to retransmit a block of data. (HARQ Hybrid Automatic Repeat Request) values are listed by PHICH Group for each subframe.
The values of the PHICHs in each PHICH group are listed in increasing order of PHICH Sequence index, starting with sequence 0 in the leftmost position and ending with NPHICHSF 1) Spreading Factor, or 2) service flow: A unidirectional flow of medium access control (MAC) service data units (SDUs) on a connection that is provided a particular Quailty of Service (QoS). - 1.
The values of the PHICHs are one of the following:
- A - ACK Acknowledgement
- N - NACK Negative Acknowledgement
- O - Off (inactive PHICH sequence index)
PBCH information
PBCH decoded information is available when PHICH Downlink Control Channel Properties: Basic tab or when PBCH Bits is set to a value other than .
or are set to in theA "CRC Cyclic Redundancy Check Invalid" message is shown when PBCH CRC fails. Otherwise the decoded PBCH contents are shown.
The following is a list of all the information contained in the PBCH section of the
trace.- - system frame number for each frame in the
- Transmission - one of 1.4MHz(6RB), 3MHz(15RB), 5MHz(25RB), 10MHz(50RB), 15MHz(75RB), 20MHz(100RB).
- C-RS Cell-specific RS antenna ports - number of
- Downlink Control Channel Properties: Basic tab. - PHICH resource Allocation size (Ng) and Duration. These values always come from the decoded PBCH bits and are unaffected by the PHICH or parameters in the
PCFICH information
Decoded PCFICH information is available when the Downlink Control Channel Properties: Basic tab or when PCFICH Bits is set to a value other than .
check box is selected in the section of theshows a comma separated list of values, one for each subframe, that indicate the number of symbols at the beginning of a subframe which are allocated to PDCCH.
PDCCH information
PDCCH information is available when RB Auto Detect Mode is set to or when PDCCH Bits is set to a value other than .
The demodulator uses the number of bits in a DCI Downlink Control Information payload to determine the DCI format. DCI formats 1b and 1d have the same number of bits and DCI format 1 can have the same number of bits as 1b and 1d. To work around these cases, the demodulator provides the DCI Formats 1, 1B, 1D Detection Include parameter.
DCI Formats 3 and 3A have the same payload length as DCI Formats 0, 1A, 1B. To work around this ambiguity, see the TPC RNTI Range parameter.
The following is a list of all the information contained in the PDCCH section of the
trace.-
- Radio Network Temporary Identifier. Identifies the intended recipient(s) of a DCI (downlink control information) transmission.
-
Downlink Control Channel Properties: Basic tab topic for more information about how the 0 dB level is defined.
- Autodetected Power Boost value for PDCCH. is reported in dB relative to the 0 dB level defined by C-RS . See theThe value reported for +/- Increments (dB) parameter has been set correctly.
can be used to verify that the PDCCH Power Boost (dB) -
- Control Channel Element Offset Start Index for decoded PDCCH
-
- Aggregation level, which is one of {1, 2, 4, 8}.
-
- DCI payload bit length (message+CRC)
- - Carrier Indicator Field (if present)
-
- DCI format, which is one of {0, 1, 1A, 1B, 1C, 1D, 2, 2A, 3, 3A}
-
- Resource block assignment contained in a DCI message
-
PUSCH Physical Uplink Shared Channel allocation
- Number of physical resource blocks assigned to PDSCH/ -
- Indicates whether Frequency Hopping is On or Off when using DCI Format 0 to schedule a PUSCH transmission.
-
- PDSCH Resource Allocation Type
PDSCH Resource Allocation types Type
Resource Allocation Type
DCI Formats
0 Bitmapped RBG allocations 1, 2, 2A 1 Bitmapped RBG Subset allocations 1, 2, 2A 2(L) Localized allocations 1A, 1B, 1D 2(D1) Distributed Ngap1 allocations 1A, 1B, 1C, 1D 2(D2) Distributed Ngap2 allocations 1A, 1B, 1C, 1D -
- Modulation and coding for transport block n
-
- New Data Indicator for transport block n
-
- Redundancy Version for transport block n
-
- Transport Block Size for transport block n
-
- Cyclic Redundancy Check result (Pass/Fail) for PDSCH transport block n, whose allocation is indicated by the PDCCH.
CRC Pass/Fail metric is only reported when RB Auto Detect Mode is set to and PDSCH Bits is set to a value other than .
- Energy Per Resource Element, per transmit antenna. - average
-
UE User Equipment (e.g. cell phone)-specific relative power level (P_A) for transport block n.
- PDSCH -
- Transport Block to Codeword Swap flag (present in DCI formats 2 and 2A)
-
UL Up Link (reverse link: from cell phone to base station) PUSCH Cyclic Shift value (present in DCI format 0)
- -
- Transmit Power Control value
For DCI formats other than 3 and 3A, the TPC Transmit Power Control value is shown as a 2-bit decimal value (0-3).
For formats 3 and 3A, the TPC value is shown as a 32-bit hex value, regardless of the payload size (
). The decoded TPC bits are located in the least significant bits and the unused most significant bits are zero padded.The payload size (TS Technical Specification 36.212, Sections 5.3.3.1.6 and 5.3.3.1.7).
) is the same as DCI Format 0 (whose payload size is L_format0 as defined in 3GPPThe LTE Long Term Evolution demodulator does not differentiate between DCI Formats 3 and 3A when showing the TPC bits and all L_format0 bits are shown.
- Format 3
- = L_format0 is even: the least significant bits contain N 2-bit TPC commands (least significant bit does not need to be zero padded in this case).
- LSB Least Significant Bit: In a binary coding scheme, the bit having the least numerical value. Analogous to the units position in a decimal number. position according to 3GPP TS 36.212, Section 5.3.3.1.6. = L_format0 is odd: the least significant bits contain N 2-bit TPC commands followed by a single zero-padded bit in the
- Format 3A: the least significant bits contain M 1-bit TPC commands.
Target uplink channel for TPC value DCI Format
Target uplink channel
Format 0 PUSCH Formats 1, 1A, 1B, 1D, 2, 2A PUCCH Physical Uplink Control Channel Formats 3, 3A PUCCH and PUSCH - Format 3
- - Hybrid Automatic Repeat Request value (present in DCI formats 1, 1A, 1B, 1C, 1D, 2, and 2A)
- TDD Time Division Duplex: A duplexing technique dividing a radio channel in time to allow downlink operation during part of the frame period and uplink operation in the remainder of the frame period. signals only and in DCI formats 0, 1, 1A, 1B, 1D, 2, 2A) - Downlink Assignment Index (present in
- - Transmitted Precoding Matrix Indicator (present in DCI formats 1B, 1D, 2, 2A)
- - confirmation of Precoding Matrix Indicator for precoding (present in DCI format 1B)
- - Downlink Power Offset (present in DCI format 1D)
- - Uplink Channel Quality Indicator request (present in DCI format 0)
- - Number of layers in DCI Format 2C
- - Port numbers in DCI Format 2C
-
- Scrambling Identity (present in DCI format 2B/2C). See Section 5.3.3.1.5B of TS 36.212.
See the nSCID parameter in the .
Querying summary table data results programmatically
To programmatically query the Trace Summary Table data results using the Summary() and SummaryUnit() methods in the MeasurementData object.
See the How To Query Summary Table Data Results topic for more information.
app.Display.Traces.SelectedItem.DataName = "Demod CCx DL Down Link (forward link: from base station to cell phone) Decode Info1";
where x specifies the component carrier
The indexes of the Profile tab of the LTE-Advanced Demod Properties dialog box. Instead of using hardcoded indexes to retrieve the data values, you can use a data result name to query the data value.
data values change depending on which channels are enabled in theBelow is a table with the list of possible data result names.
Data Result Name |
Description |
---|---|
PBCH Decoder PCFICH Decoder PDCCH Decoder PDSCH Decoder |
Decoder status for channel: On or Off |
PBCH_Fx_IE | Decoded information from PBCH for frame x |
PCFICH_Fx_IE | Decoded information (number of PDCCH symbols allocated for each subframe) decoded from PCFICH for frame x |
PHICH_Fx_SFnIE | Decoded HARQ Ack/Nack from PHICH for frame x and subframe n |
PDCCH_Fx_SFnIE#t | Decoded DCI message from PDCCH for frame x, subframe n, and transport block t |
In the data result names above, x = 0 indicates the first frame found in the Measurement Interval.
See Also