Method for Handling a Mobility Management State Transition After Fallback to RRC Establishment

Abstract

This document describes techniques and apparatuses for handling mobility management state transitions after fallback to radio resource control (RRC) establishment. In implementations, a user equipment (UE) transmits an RRC request to a network to initiate an RRC connection procedure. Afterward, the UE receives an RRC setup message from the network. The UE communicates, by an RRC protocol layer at the UE, an indication of the fallback to a fifth-generation mobility-management (5GMM) protocol layer at the UE. The UE then transitions the 5GMM protocol layer to a 5GMM idle state. In implementations, the UE then communicates, by the RRC protocol layer, an RRC connection-established indication to the 5GMM protocol layer, and transitions the 5GMM protocol layer to a 5GMM connected state to enable data transmission and reception with the network.

1 . A method performed by a user equipment for handling a mobility management state transition after fallback to a radio-resource-control establishment, the method comprising:
 transmitting a radio-resource-control request to a network to initiate a radio-resource-control connection procedure;   receiving, in response to the transmitting the radio-resource-control request, a radio-resource-control setup message from the network;   communicating, from a radio-resource-control protocol layer at the user equipment to a fifth-generation mobility-management protocol layer at the user equipment, an indication of the fallback based on the receiving;   transitioning the fifth-generation mobility-management protocol layer to a fifth-generation mobility-management idle state;   communicating, from the radio-resource-control protocol layer to the fifth-generation mobility-management protocol layer, a radio-resource-control connection-established indication; and   transitioning the fifth-generation mobility-management protocol layer to a fifth-generation mobility-management connected state to enable data transmission and reception with the network.   
     
     
         2 . The method of  claim 1 , further comprising:
 starting, by the fifth-generation mobility-management protocol layer, a timer in response to receiving the indication of the fallback; and   stopping, by the fifth-generation mobility-management protocol layer, the timer in response to receiving the radio-resource-control connection-established indication.   
     
     
         3 . The method of  claim 1 , further comprising:
 receiving a radio-resource-control reconfiguration message from the network;   configuring a data radio bearer based on the radio-resource-control reconfiguration message; and   communicating, from the radio-resource-control protocol layer to the fifth-generation mobility-management protocol layer, an indication that user-plane resources have been established.   
     
     
         4 . The method of  claim 3 , further comprising:
 communicating, from the fifth-generation mobility-management protocol layer to a data service protocol layer, an indication of an unavailable data connection in response to receiving the indication of the fallback; and   communicating, from the fifth-generation mobility-management protocol layer to the data service protocol layer, an indication of an available data connection in response to the indication that the user-plane resources have been established.   
     
     
         5 . The method in  claim 1 , wherein the radio-resource-control connection procedure is a radio-resource-control connection-reestablishment procedure, and
 the radio-resource-control request comprises a radio-resource-control reestablishment request.   
     
     
         6 . The method of  claim 5 , further comprising:
 transmitting, in response to the receiving the radio-resource-control setup message, a radio-resource-control setup-complete message to the network, wherein the radio-resource-control setup-complete message includes a fifth-generation mobility-management message generated by the fifth-generation mobility-management protocol layer, wherein the fifth-generation mobility-management message comprises:   a service request; or   a registration request.   
     
     
         7 . The method of  claim 6 , further comprising:
 receiving, by the fifth-generation mobility-management protocol layer, an indication of a failure in a radio-resource-control connection from the radio-resource-control protocol layer; and   generating, by the fifth-generation mobility-management protocol layer, the fifth-generation mobility-management message in response to receiving the indication of the failure in the radio-resource-control connection.   
     
     
         8 . The method of  claim 6 , further comprising:
 generating, by the fifth-generation mobility-management protocol layer, the fifth-generation mobility-management message in response to receiving the indication of the fallback.   
     
     
         9 . The method of  claim 6 , further comprising:
 generating, by the fifth-generation mobility-management protocol layer, the fifth-generation mobility-management message in response to receiving the radio-resource-control connection-established indication.   
     
     
         10 . The method in  claim 1 , wherein the radio-resource-control connection procedure is a radio-resource-control connection-resume procedure, and
 the radio-resource-control request comprises a radio-resource-control resume request.   
     
     
         11 . The method of  claim 10 , further comprising:
 transitioning, in response to receiving the radio-resource-control setup message, the radio-resource-control protocol layer to a radio-resource-control connected state.   
     
     
         12 . The method of  claim 10 , further comprising:
 transmitting, in response to the receiving the radio-resource-control setup message, a radio-resource-control setup-complete message to the network, wherein the radio-resource-control setup-complete message includes a fifth-generation mobility-management non-stratum-access message generated by the fifth-generation mobility-management protocol layer, wherein the fifth-generation mobility-management non-stratum-access message comprises:   a service request; or   a registration request.   
     
     
         13 . The method of  claim 12 , further comprising:
 generating, by the fifth-generation mobility-management protocol layer, the fifth-generation mobility-management non-stratum-access message in response to receiving the indication of the fallback.   
     
     
         14 . The method of  claim 12 , further comprising:
 generating, by the fifth-generation mobility-management protocol layer, the fifth-generation mobility-management non-stratum-access message in response to receiving the radio-resource-control connection-established indication.   
     
     
         15 . A user equipment comprising:
 a wireless transceiver; and   a processor and memory system coupled to the wireless transceiver, the memory system comprising processor-executable instructions that, responsive to execution by the processor, direct the user equipment to perform operations for handling a mobility management state transition after fallback to a radio-resource-control establishment, the operations comprising:
 transmitting a radio-resource-control request to a network to initiate a radio-resource-control connection procedure; 
 receiving, in response to the transmitting the radio-resource-control request, a radio-resource-control setup message from the network; 
 communicating, from a radio-resource-control protocol layer at the user equipment to a fifth-generation mobility-management protocol layer at the user equipment, an indication of the fallback based on the receiving; 
 transitioning the fifth-generation mobility-management protocol layer to a fifth-generation mobility-management idle state; 
 communicating, from radio-resource-control protocol layer to the fifth-generation mobility-management protocol layer, a radio-resource-control connection-established indication; and 
 transitioning the fifth-generation mobility-management protocol layer to a fifth-generation mobility-management connected state to enable data transmission and reception with the network. 
   
     
     
         16 . The user equipment of  claim 15 , the memory system comprising processor-executable instructions that direct the user equipment to perform further operations comprising:
 starting, by the fifth-generation mobility-management protocol layer, a timer in response to receiving the indication of the fallback; and   stopping, by the fifth-generation mobility-management protocol layer, the timer in response to receiving the radio-resource-control connection-established indication.   
     
     
         17 . The user equipment of  claim 15 , the memory system comprising processor-executable instructions that direct the user equipment to perform further operations comprising:
 receiving a radio-resource-control reconfiguration message from the network;   configuring a data radio bearer based on the radio-resource-control reconfiguration message; and   communicating, from the radio-resource-control protocol layer to the fifth-generation mobility-management protocol layer, an indication that user-plane resources have been established.   
     
     
         18 . The user equipment of  claim 15 , wherein the radio-resource-control connection procedure is a radio-resource-control connection-reestablishment procedure, and
 the radio-resource-control request comprises a radio-resource-control reestablishment request.   
     
     
         19 . The user equipment of  claim 18 , the memory system comprising processor-executable instructions that direct the user equipment to perform further operations comprising:
 transmitting, in response to the receiving the radio-resource-control setup message, a radio-resource-control setup-complete message to the network, wherein the radio-resource-control setup-complete message includes a fifth-generation mobility-management message generated by the fifth-generation mobility-management protocol layer, wherein the fifth-generation mobility-management message comprises:
 a service request; or 
 a registration request. 
   
     
     
         20 . The user equipment of  claim 19 , wherein the radio-resource-control connection procedure is a radio-resource-control connection-resume procedure, the radio-resource-control request comprises a radio-resource-control resume request, and
 wherein the memory system comprising processor-executable instructions that direct the user equipment to perform further operations comprising:   transitioning, in response to receiving the radio-resource-control setup message, the radio-resource-control protocol layer to a radio-resource-control connected state.