top button
Flag Notify
    Connect to us
      Site Registration

Site Registration

5G: What is the use of signalling radio bearer 3 (SRB3) and when it is established ?

+3 votes
4,174 views

In the LTE network, as per my knowledge only SRB1 and SRB2 two signalling radio bearers were supported for an UE. SRB1 mainly used to RRC messages and optionally NAS messages if SRB2 (optional) is unavailable. If SRB2 is available, NAS messages are transported between UE and MME using SRB2 signalling bearer.
Now I want to know what is the use of another SRB3 ? Is it established along with SRB1 and SRB2 every time or it is optional and established only on specific cases/scenarios ?

posted Feb 22, 2018 by Harshita

Share this question
Facebook Share Button Twitter Share Button LinkedIn Share Button

2 Answers

+1 vote

Many 5G deployment options have been defined yet. Majorly one is known as non-standalone while the other one is known as standalone deployment. In case of non-standalone deployment, both eLTE RAN and NG RAN nodes would be available to serve 5G handsets either through LTE EPC or NGCN. In case of standalone deployment, either eLTE RAN or NG RAN node will be deployed with NGCN.
In non-standalone deployment, SRB3 is a dedicated signalling radio bearer which is used to transport NR RRC PDUs directly between UE and NR node. If SRB3 is not established between UE and NG RAN, NG RAN RRC PDUs are sent to UE by using the SRB1 (established between eLTE and UE).

answer Feb 23, 2018 by Ganesh
+1 vote

some add on -
SRB3 shall carry only following messages
1- rrcConnectionReconfiguration
2- rrcConnectionReconfigurationComplete
3- measurementReport

answer Jun 5, 2018 by Brajesh Soni
Similar Questions
+1 vote

In LTE network, OFDMA is being used for downlink and S-FDMA is for uplink direction.
What about 5G radio access mechanism ? How radio resources would be accessed by 5G handsets ?

0 votes

I want to understand beam forming concept and why it is considered for 5G ?

...