Patent ID: 8831650

Claim:
A method of exchanging short message service (SMS) data in a wireless communications system comprising a user equipment (UE) and a core network unit interfaced with the UE through a wireless access network, wherein a first short message relay (SMR) entity and a first short message control (SMC) entity are provided in the UE, and a second SMR entity and a second SMC entity are provided in the core network unit, the method comprising: for a mobile originated (MO) message, transmitting, at the first SMC entity, first control protocol (CP) data to the second SMC entity, the first CP data conveying relay protocol (RP) data provided by the first SMR entity for the second SMR entity; starting a timer of the UE when transmitting the first CP data; in response to the first CP data, receiving, at the first SMC entity from the second SMC entity, second CP data conveying RP acknowledgement information from the second SMR entity, wherein no CP acknowledgement is received from the second SMC entity before the RP acknowledgement information is received at the second SMC entity; stopping the timer of the UE if the second CP data conveying the RP acknowledgement information is received at the first SMC entity; and retransmitting the first CP data if the second CP data conveying the RP acknowledgement information is not received at the first SMC entity before the timer of the UE expires.