Physical Downlink Shared Channel-PTRS

This modules generates a resource grid with Phase Tracking Reference Signal (PTRS) for physical downlink shared channel (PDSCH) mapped to a resource grid.

Generating PDSCH-PTRS Resource Grid Case-1:

numBatches          = 7
numRB               = 20
pdschMappingType    = "PDSCH-mapping-type-A"
maxLength           = "len1"
startSymbol         = 0
numSymbols          = 4
configurationType   = "Configuration-type-1"
ld                  = numSymbols
rank                = 2
rnti               = np.random.randint(65536, size=numBSs*numBatches)
scramblingID  = int(np.random.randint(65535, dtype = int)) # or Cell-ID for Initial Access
nSCID         = int(np.random.randint(2, dtype = int))
#PTRS parameters
offsetIndex = '00'
lptrs = 1
kptrs = 2
RMptrspdsch  = ResourceMapperPTRSpdsch(lptrs,kptrs,offsetIndex)
resourceGrid = RMptrspdsch(rank,configurationType,startSymbol,ld,numRB,rnti,scramblingID,nSCID,numBatches,numBSs=1)

Display the PTRS-PDSCH Resource Grid:

fig0, ax0 = RMptrspdsch.DisplayResourceGrid()

Generating PDSCH-PTRS Resource Grid Case-2:

numBatches          = 3
numRB               = 40
pdschMappingType    = "PDSCH-mapping-type-B"
maxLength           = "len2"
startSymbol         = 1
numSymbols          = 7
configurationType   = "Configuration-type-2"
ld                  = numSymbols
rank                = 4
rnti                = 12557
scramblingID        = 34956
nSCID               = 0
#PTRS parameters
offsetIndex = '00'
lptrs               = 4
kptrs               = 4
RMptrspdsch         = ResourceMapperPTRSpdsch(lptrs,kptrs,offsetIndex)
resourceGrid        = RMptrspdsch(rank,configurationType,startSymbol,ld,numRB,rnti,scramblingID,nSCID,numBatches,numBSs=1)

Note: The Rank, Start Symbol and Number of Symbol must be chosen in accordance to the configuration, mapping types and max length

Display the PTRS-PDSCH Resource Grid:

fig1, ax1 = RMptrspdsch.DisplayResourceGrid()

class toolkit5G.ResourceMapping.ResourceMapperPTRSPDSCH(lptrs, kptrs, offsetIndex)

To Generate Phase Tracking reference Signal and Allocate it resource Elements in accordance with 7.4.1.2.2 3GPP TS38.211

Parameters:

• lptrs (int) – Defines the Time Density \(\in \{1, 2, 4\}\). This variable is defined in 3GPP TS 38.211 Section 7.4.1.2.2 as \(L_{PT-RS}\).

• kptrs (int) – Defines the Frequency Density \(\in \{2,4\}\). This variable is defined in 3GPP TS 38.211 Section 7.4.1.2.2 as \(K_{PT-RS}\).

• offset Index (str) – Used to compute resource element Offset \(\in \{00,01,10,11\}\). This variable is defined in 3GPP TS 38.211 Section 7.4.1.2.2, Table 7.4.1.2.2-1 as \(\{\) ‘offset00’, ‘offset01’, ‘offset10’, ‘offset11’ \(\}\).

Input:

• rank (str) – Defines the number of Ports \(\in \{1,2, \dots ,8\}\) for ‘Configuration-type-1’ and \(\in \{1,2, \dots ,12\}\) for ‘Configuration-type-2’

• configurationType (str) – Defines configuration type for PDSCH \(\in \{\) ‘Configuration-type-1’, ‘Configuration-type-2’ \(\}\).

• pdschStartSymbol (int) – Defines the starting symbol for PDSCH allocation :math in {0,1,dots,4} for ‘Single/Double Symbol Mapping Type A’ and \(\in \{0,1,\dots,13\}\) for ‘Single Symbol Mapping type B’ and \(\in \{0,1,\dots,7\}\) for ‘Double Symbol Mapping type B’

• ld (int) – Defines Number of symbols taken for PDSCH Transmission \(l_d\) parameter of PDSCH-DMRS. It takes values \(\in \{2,3,4,5,6,7,8,9,10,11,12,13\}\)

• numRBs (int) – Defines number of physical resource blocks (PRBs) occupied for PDSCH transmission.

• scramblingID (int) – Defines the scramblingID \(\in \{0,1,\dots,65535\}\).

• nSCID (int) – Defines the quantity \(\text{𝑛}_{\text{SCID}} \in \{0,1\}\) is given by the DM-RS sequence initialization field.

Output:

[numBatches, numBSs, numPorts, 14, numResourceBlocks*12], np.complex32 – Phase Tracking reference signal (PTRS) for PDSCH (PTRS-PDSCH) Grid.

Raises:

• ValueError – [Error PDSCH-PTRS RM] PTRS Not supported for Configuration-type-1 when rank greater than 4

• ValueError – [Error PDSCH-PTRS RM] Enter valid offset index

• ValueError – [Error PDSCH-PTRS RM] Enter a Valid configuration

• ValueError – [Error PDSCH-PTRS RM] lptrs must be an Integer value

• ValueError – [Error PDSCH-PTRS RM] lptrs can take values 1,2 and 4 only

• ValueError – [Error PDSCH-PTRS RM] kptrs must be an Integer value

• ValueError – [Error PDSCH-PTRS RM] kptrs can tale values 2 and 4 only

• ValueError – [Error PDSCH-PTRS RM] offsetIndex must be a string

• ValueError – [Error PDSCH-PTRS RM] offsetIndex can take values 00,01,10 & 11 only

• ValueError – [Error PDSCH-PTRS RM] configurationType must be an string

• ValueError – [Error PDSCH PTRS RM] ‘configurationType’ must be ‘Configuration-type-1’ or ‘Configuration-type-2’!

References:

[3GPPTS38211_pdschDMRS]

(3GPP TS 38.211 version 17.1.0 Release 17) 5G;NR;Physical channels and modulation ‘5.2.2 Low-PAPR sequence generation type 1’