SCS (sub-carrier space)-sub-carrier space
SCS is the space between 2 OFDM symbols.
In LTE it is fixed at 15KHz.
In 5G NR, there are 5 possible values based on numerology.
In the time domain, 5G and LTE are the same: 1 frame=10ms, 1 frame contains 10 subframes, and each subframe=1ms.
PointA is a reference point in frequency domain to allocate other resources.
Below parameters define PointA
> offsetToPointA : This parameter defines the frequency deviation between Point A and the lowest point in the frequency domain.
> absoluteFrequencyPointA : This parameter directly defines the frequency of Point A, the unit is ARFCN.
CRB stands for Common Resource Block and it is the center of Subcarrier 0 of CRB0 is PointA.
RE: Resource Element
RE is the smallest resource unit in NR phy resource.
It will occupy 1 OFDM symbol in time domain and 1 Sub Carrier in frequency domain.
RB: Resource Block
It will occupy 12 sub carriers in frequency domain.
RBG: Resource Block Group
REG: Resource Element Group
It is a control channel resource, it consist of 1 ofdm symbol × 12 subcarrier, i.e, one REG contains 12 REs
CCE: Channel Control Element
It is a unit of PDCCH resource allocation.
A CCE occupies 6 REGs.
It is used to decode PDCCH in this region.
There are 2 different types of CORESET.
1. Common Control Region: This is referred as common CORESET and is shared by multiple UE in a cell. It can be used for RAR/paging/system information,
2. UE Specific Region:This is defined for one particular UE.
Network can define 3 CORESET per BWP.
A search space is a set of control channel elements at a different aggregation levels.
A CORESET may have multiple search space, where UE attempts for blind decoding.
It is used to inform UE the number of bits used for PDCCH transmission.
Possible aggregation level in NR is — 1,2,4,8,16
Aggregation Level = 6 REG and REG = 12 RE, so one aggregation level means (72 RE)
Bandwidth Part (BWP):
BWP is a subset of CRB.
There are 4 different types of BWP:
1. Initial BWP
2. Dedicated BWP
3. Activate BWP
4. Default BWP