Physical Downlink Control Channel (PDCCH)

This module maps the Physical Control Channel (PDCCH) payload onto the resource grid as per control resource set configurations. The demodulation reference signal (DMRS) for PDCCH is filled in resource grid to equalizing information at the receiver. [3GPPTS38211PDCCHRM]

class toolkit5G.ResourceMapping.ResourceMappingPDCCH(AL, interleaverType, L, R, nshift)

Generates the resource grid loaded with PDCCH as per Section 7.3.2.5 of [3GPPTS38211_PDCCHRM]. The DMRS are automatically loaded into the resource grid as per the configurations.

Parameters:

• AL (int) – Define aggregation level. The number of Resource Elements (REs) of a CORESET that are required to carry a PDCCH DCI message is called Aggregation level \(\in \{1,2,4,8,16\}\). It is equal to number of control channel elements (CCEs. “A control-channel element consists of 6 resource-element groups (REGs) where a resource-element group equals one resource block during one OFDM symbol. Resource-element groups within a control-resource set are numbered in increasing order in a time-first manner, starting with 0 for the first OFDM symbol and the lowest-numbered resource block in the control resource set.”

• interleaverType (str) – Define CCE-to-REG mapping type \(\in \{\text{"interleaved"}, \text{"non-interleaved"}\}\).

• L (int) – Define REG Bundle Size \(\in \{2,3,4\}\).

• R (int) – Define Interleaver Size \(\in \{2,3,4\}\).

• nshift (int) – Define resource block offset \(\in \{0,1,\dots,\text{N}_\text{RB}-1\}\).

Important

Not all combination of L, R and AL are supported. The valid values of these parameters are described in Section 7.3.2.2 of [3GPPTS38211_PDCCHRM].

Input:

• pdcchPayload ((numPDCCHBits,1), int) – Defines the payload bits to be loaded in the configured CORESET. The number of PDCCH bits, numPDCCHBits = \(0.75 \times \text{N}_\text{RB} \times 12 \times \text{duration}\). The 0.75 of the total PDCCH resources are occupied by the payload and the remaining 1/4 resources are used by DMRS.

• frequencyDomainResources ((45,1), int) – Defines frequency domain resources which must be a 45 length array whose each bit allocates 6 contiguous RBs, with grouping starting from PRB 0, to CORESET within the bandwidth part within which the CORESET is configured. The 0th entry points to the lowest RB in the configured BWP. The number of RBs allocated to CORESET/PDCCH is given by \(\text{N}_\text{RB}\) = 6*np.sum(frequencyDomainResources)

• duration (int) – Defines the contiguous number of OFDM symbols allocated to CORESET.

• slotNumber (int) – Defines the slot number within a frame where PDCCH is loadedS \(n_{s,f}^{\mu} \in \{0,1,2,\) \(\dots,10*2^{\mu}-1\}\) where \({\mu = \frac{\Delta f}{15 kHz}}\).

• scramblingID (int) – Defines the scramblingID \(\in \{0,1,\dots,4095\}\).

Output:

[14, numSubcarriers], np.complex64 where numSubcarriers = frequencyDomainResources.size \(\times 6\times 12\). – Physical downlink control channel (PDCCH) resource Grid.

Raises:

• ValueError – [Error in resourceMappingPDCCH]: ‘numRB’ must be integer!

• ValueError – [Error in resourceMappingPDCCH]: ‘NsymbPerSlots’ must be integer!

• ValueError – [Error in resourceMappingPDCCH]: ‘duration’ must be 1, 2 or 3!

• ValueError – [Error in resourceMappingPDCCH]: ‘duration’ must be integer!

• ValueError – [Error in resourceMappingPDCCH]: ‘frequencyDomainResources’ must be integer array!

References:

[3GPPTS38211PDCCHRM]

(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’