6 SLm interface protocol structure

36.4563GPPEvolved Universal Terrestrial Radio Access Network (E-UTRAN)Release 17SLm interface general aspects and principlesTS

Editor’s Note: Protocol Structure following the structure defined in TS 36.305 [2].

6.1 General

The network signalling over SLm consists of the SLm Application Protocol (SLmAP). The SLmAP consists of mechanisms to handle all procedures between the E-SMLC in the EPC and LMUs in the E-UTRAN.

Over the SLm interface the SLmAP protocol is, e.g., used to:

– Request LMUs to perform UL RTOA measurements of target UE SRS transmissions.

– Transfer of completed UL RTOA measurements from the LMU to the E-SMLC.

6.2 SLmAP

Figure 6.1 shows the protocol structure for SLmAP, following the structure described in TS 36.305 [2].

Figure 6.1: Interface protocol structure for SLmAP

The Transport Network Layer is based on IP transport, comprising SCTP on top of IP.