5G/NR - Resource Grid                   Home : www.sharetechnote.com

 

 

 

 

 

Resource Grid

 

 

The resource grid for NR is defined as follows. If you just take a look at the picture, you would think it is almost identical to LTE resource grid. But the physical dimmension (i.e, subcarrier spacing, number of OFDM symbols within a radio frame) varies in NR depending on numerology.

 

 

Resource Element : This is same as LTE. It is the smallest unit of the resource grid made up of one subcarrier in frequency domain and one OFDM symbol in time domain.

 

Resource Block: In NR, Resource Block is defined only for frequency domain. 38.211-4.4.4.1 states 'A resource block is defined as 12(N_RB_sc) consecutive subcarriers in the frequency domain'.

Time domain definition of resource block is a little bit ambiguous. Minimum time domain length in a resource block can be one OFDM symbol, but exact time domain length vary depending SLIV.

 

Resource Grid and Antenna port and Numerology  : Basically one resource grid is created for one antenna port and numerology. 38.211-4.2.2 states as follows.

 

 

 

 

The maximum and minimum number of Resource blocks for downlink and uplink is defined as below (this is different from LTE)

 

< 38.211 Table 4.4.2-1: Minimum and maximum number of resource blocks.>

 

Following is the table that I converted the downlink portions of Table 4.4.2-1 into frequency Bandwidth just to give you the idea on what is the maximum RF bandwidth that a UE / gNB need to support for single carrier.

 

u

min RB

Max RB

sub carrier spacing

(kHz)

Freq BW min

(MHz)

Freq BW max

(MHz)

0

24

275

15

4.32

49.5

1

24

275

30

8.64

99

2

24

275

60

17.28

198

3

24

275

120

34.56

396

4

24

138

240

69.12

397.44

 

 

 

 

 

Reference

 

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