ETSI TS 103 720 V1.2.1 - Delivery of Warning Messages from MME to eNodeB

[kuehnhammer]

Context

5.15.1 Reference architecture specifies the end-to-end interfaces and delivery flow for warning messages, but has a gap between MME and eNodeB.

Problem description

Figure 5.15.2-1 shows Write-Replace Warning Request/Response messages, which correspond to the Warning Message Transmission Procedures specified in interface S1AP (3GPP TS 36.413).

The S1 interface is the direct 1:n connection between MME and eNodeBs, but is not specified (nor otherwise useful or needed) in the reference architecture for LTE-based 5G Broadcast.

The existing connection from MME to eNodeB via the MCE (interfaces M3 and M2) has no comparable messages or procedures.

Suggested solution

To be discussed.

Either:

• extend LTE-based 5G Broadcast architecture with a direct S1 interface between eNb and MME, possibly limiting its required implementation to Warning Message Transmission Procedures
• extend the M2 and M3 protocols to include similar procedures
• add a new interface

[rjb1000]

Better to add reference point S1 to the reference architecture in figure 5.1.1-1 of TS 103 720, I think. The description of this reference point should indicate that only a subset of messages are relevant to PWS, per the procedures in clause 5.515.2 and as profiled in a new clause 5.15.3.2A. That new clause would list Write-Replace Warning request/response as the relevant messages.

Then figure 5.15.1-1 could be modified to relabel M3 as S1. The MCE would also need to be added per the suggestions on #83, but ghosted out since it plays no role in PWS deployments.

[dvargasparedero]

Action from WG CD call:

• combine with #77