5G PRB calculator

Abstract: In LTE (Long Term Evolution) systems, the PRB (Physical Resource Block ) usage ratio is considered importantly to manage the QoS (Quality of Service) of LTE traffic. As the PRB usage ratio increases, the resource may not be allocated in a timely and reliable manner to the users of the cell.

Physical Resource Block (PRB) = 2*Resource Block = 12 Subcarriers x 14 OFDM in 1ms . RE can deliver 2, 4, 6, 8 bits in QPSK, 16QAM, 64QAM, 256QAM respectively. If we calculate for 64QAM as 6bits since 256QAM not widely spread (check Samsung S7 in T-Mobile). 20MHz ==> 100 PRB ==> 100*168*1000 = 16,800,000 RE in 1 s.

Resource Element(RE) : The smallest unit made up of 1 symbol x 1 subcarrier. RB (Resource Block) : I think everybody would know what this is. This is a unit of 84 resource elements which is 12 subcarrier by 7 symbols (This is with normal Cylic Prefix which is used in most of the LTE deployment.

5G NR retains the concept of 10 millisecond frame divided into 10 one-millisecond subframes.

In comparison, 5G NR maximum carrier bandwidth is up to 100 MHz in frequency range 1 (FR1: 450 MHz to 6 GHz), or up to 400 MHz in frequency range 2 (FR2: 24.25 GHz to 52.6 GHz) that can be aggregated with a maximum bandwidth of 800 MHz.