Sign in Subscribe
Posts

Learn about 5G DMRS for PBCH

Mohamed ELAdawi

Mohamed ELAdawi

— 1 min read
Learn about 5G DMRS for PBCH

Learn about 5G DMRS for PBCH

(1) What is the primary function of DMRS for PBCH?

  • The UE uses DMRS to estimate the propagation channel experience by the PBCH. The resultant information is used to demodulate the PBCH and subsequently decode the Master Information Block.

(2) How and where is it being transmitted?

  • The DMRS for the PBCH is transmitted by the Base Station using antenna port 4000. (PBCH is transmitted within SSB Block in Symbols 1, 2, and 3, as shown below.
  • There are no Resource Elements for the DMRS within the first symbol(S0), as the PBCH does not use this symbol.

(3) Where is it being allocated within S1, S2, and S3, and what overhead is added by DMRS for PBCH?

  • The DMRS is allocated to every 4th Resource element and is designed based on PCI mod 4. DMRS Occupy 25% of the PBCH REs Per Resource Block.
💡
*Where S1/S3 = 20RB * 3 DMRS RE = 60RE, and S2= 8RB * 3 DMRS RE = 24RE
*RB: Resource Block, RE: Resource elements

Study Sources: 5G NR in Bullets & 3GPP TS 38.211

Refer to the below video for more details:

Read more

5G HARQ Explained: Soft Combining, HARQ Processes, ACK/NACK Timing, Codebook Types, Spatial Bundling, and 4G vs 5G Differences (Article)

5G HARQ Explained: Soft Combining, HARQ Processes, ACK/NACK Timing, Codebook Types, Spatial Bundling, and 4G vs 5G Differences (Article)

Introduction * HARQ is one of the most important reliability mechanisms in the 5G MAC layer. It directly affects retransmission speed, uplink control overhead, latency, and overall scheduling efficiency. * In simple words, HARQ gives 5G a fast retransmission loop. It helps recover transmission errors much faster than higher-layer recovery, which is

By Mohamed ELAdawi