Fallback assistance information

A method comprising:

• receiving, at a radio access network (“RAN”) node, a first message from a network function in a first core network, wherein the first message indicates service fallback of a remote unit connected to the RAN node and indicates a target system;
• creating service fallback parameters for the remote unit, wherein the target system is used to execute one of:
• inter-RAT redirection and inter-system redirection, wherein inter-system redirection is triggered if the target system is different than a current system of the remote unit;
• and
• sending a connection release message to the remote unit, where the connection release message includes redirection information for service fallback, the redirection information including a target radio access technology (“RAT”) cell and the target system, wherein the target system is used to resolve the target RAT cell.

An apparatus comprising:

• a transceiver that receives a first message from the network function, wherein the first message indicates service fallback of the remote unit and indicates a target system;
• and
• a processor that creates service fallback parameters for the remote unit, wherein the target system is used to execute one of:
• inter-RAT redirection and inter-system redirection, wherein inter-system redirection is triggered if the target system is different than a current system of the remote unit,
• wherein the transceiver sends a connection release message to the remote unit, the connection release message including redirection information for the service fallback, the redirection information including a target radio access technology (“RAT”) cell and the target system, wherein the target system is used to resolve the target RAT cell.

A method comprising:

• receiving, at a network function part of a first core network, a service request from a remote unit, wherein the service request is for a service which requires fallback to at least one of:
• a different radio access technology (“RAT”) and a different system;
• identifying, at the network function, at least one of:
• a target RAT and a target system, based on at least one of the requested service, remote unit capabilities and network configuration;
• and
• indicating, to a radio access network (“RAN”) node, the at least one of:
• a target RAT and a target-GN system, based on the requested service, wherein the RAN node performs fallback with the remote unit based on the at least one of:
• a target RAT and a target system.