The S1 Application Protocol (S1AP) provides the control plane signalling between E-UTRAN and evolved packet core (EPC). The used interface is S1-MME which is located between eNB and MME. The services provided by the S1AP are divided to UE associated and non UE associated.
What is S1 and X2 handover in LTE?
The X2 procedure is used to handover a UE from a source (H)eNB to a target (H)eNB for which the MME is unchanged. The S1 procedure is used by the source eNB to initiate a handover through the S1-MME interface, see [4].
What is the S1 interface?
The S1 interface connects the eNB to the EPC. It can be split into control-plane (S1-MME) and user-plane (S1-U). The S1-MME is a signaling interface which supports a set of functions and procedures between the eNB and the MME. The role of S1-U is to transport user data packets between the eNB and the S-GW.
What is X2 and S1 interface?
eNodeBs have two interfaces, the X2 interface permits eNodeBs to intercommunicate with each other directly, and the S1 interface permits communication with the “Packet Core”. The X2 is the interconnecting interface between two eNodeBs in LTE network and supports both Control Plane and User Plane.
What is S1 bearer?
An S1 bearer is the connection between the eNodeB and the MME/SGW. Finally, the EPS bearer is established between the EPS and the MME and the SGW, and the SGW and the PGW.
What is S1 setup request?
This message is sent by the eNB to transfer information for a TNL association.
What is X2 handover in LTE?
eNodeBs in LTE are interconnected with the X2 interface. If two eNodeBs are served by the same MME, handover from the source to the target eNodeB will take place over the X2 interface.
What is S1 MME interface in LTE?
The LTE S1-MME interface is responsible for delivering signaling protocols between the eNodeB and the MME. S1-MME interface consists of a Stream Control Transmission Protocol (SCTP) over IP and supports multiple UEs through a single SCTP association. It also provides guaranteed data delivery.
What are LTE interfaces?
Within an LTE network, LTE Interfaces connect the various components to or within the core. Interfaces allow the MME, SGW and PGW to cooperate with other network elements (e.g. HSS or PCRF). Each one of them is built in a standard way described by 3GPP.org.
What is S1 interface in 5G?
In LTE networks, X2 and S1 interface are defined as an interfaces between RAN nodes and between RAN and Core Network. 5G is expect to operate in two modes as non -standalone and standalone mode of operation. Interface between RAN and Core Network as S1/NG.
What is LTE bearer type?
It include LTE EPS bearer, external bearer, E-RAB, S1 bearer, S5 bearer, S8 bearer, LTE radio bearer etc. LTE system provides end to end service using the hierarchy of LTE bearers shown in the figure. An LTE EPS bearer provides user plane connectivity between the UE and PDN gateway.
What is 4G bearer?
In a mobile network using the Long Term Evolution (LTE) architecture, bearers are the tunnels used to connect the user equipment to Packet Data Networks (PDNs) such as the Internet. The maximum of 11 still holds in 4G/LTE networks.
What is an S1 handover for UE?
UE is handed over using an S1 handover if the X2 interface is not available between the source and target eNodeB Message interactions involving the eNodeB that was serving the UE at the time of handover
What are the different types of handovers supported by LTE?
LTE supports two types of handover: X2-based handover and S1-based handover. The X2-based procedure is the least complex handover and typically would be used when an X2 interface exists between the source eNB and the target eNB.
How does the source eNodeB initiate an s1-based handover?
The source eNodeB decides to initiate an S1-based handover to the target eNodeB. This can be triggered e.g. by no X2 connectivity to the target eNodeB, or by an error indication from the target eNodeB after an unsuccessful X2-based handover, or by dynamic information learnt by the source eNodeB.
What is the procedure for handover from LTE to another rat?
In general, the procedure for handover from LTE to another RAT supports both handover and CCO with network-assisted cell change (NACC). The CCO/NACC procedure is applicable only for handover to GERAN. Handover from LTE is performed only after security has been activated.
