In LTE, a Physical Resource Block (PRB) is defined as consisting of 12 consecutive subcarriers for one slot (0.5 ms), and is the smallest element of resource allocation assigned by the eNodeB scheduler.
But i also read it as Resource Block (RB), so I’m getting confused… What’s the tricky in here?
My query is: is RB and PRB exactly the same? (One RB = One PRB?). When to use RB and when to use PRB?
RB (Resource Block) and PRB (Physical Resource Block) are exactly the same. 12 subcarriers x 7 symbols. The green rectangular in your image is correct.
PRB is usually used to differentiate Resource Block from RB (Radio Bearer).
My take on this is: RB and VRB are logical definitions while PRB is the effective physical allocation into the time and frequency domain grid.
There is a 1:1 map between RB/VRB and PRB size, and it is important to remember that theorethically, a PRB lasts 0.5ms not 1ms.
3GPP TS 36.211 version 15.8.1 Release 15 6.2.3 Resource blocks Resource blocks are used to describe the mapping of certain physical channels to resource elements. Physical and virtual resource blocks are defined.
(…)
A physical resource-block pair is defined as the two physical resource blocks in one subframe having the same physical resource-block number nPRB.
12 SC, 7 ofdma symbol = 1 RB or 1 PRB
12 SC, 14 ofdma symbol = 1 SB(Scheduling Block, smallest block to give to a user)
The above are Ericsson Terminalogy. I am not very sure if SB is 3gpp terminalogy as well or not
Hence from the quoted information its clear that the dimensions of RB & PRB are the same in LTE. although both are different logically. RB is a virtual concept assigned by MAC while PRB is the actual physical resource allocated to the user.
Regarding the comment about the Mpirical definition being incorrect, I contacted them about this matter. The person responsible for the air interface material corrected this and elaborated further, defining this both in 4G LTE and 5G, since they are different. He even included a note on LTE NB-Iot. I am confident that the revised definition is both clear and correct.
Thanks to Rafael Demasio for pointing out the error.
I think I’m a bit confused with RB and PRB in LTE still. Reading the explanation of PRB - “The LTE PRB (Physical Resource Block) is made up of 12 consecutive subcarriers for a duration of one slot (0.5 ms)” this would mean that for 1 ms (1 Subframe) there are 2 PRBs or the same PRB but duplicated? Because if it is 2 PRBs for 1 ms that would mean that for 20 MHz bandwidth there should be 200 PRBs not 100 PRBs (Guard Band part here).
What am I getting wrong?
