Patent ID: 8792338

Claim:
A method of performing radio access congestion control in a wireless communication system using a number of orthogonal frequency-division multiplexing (OFDM) symbols, the method performed by a user equipment (UE) and comprising: setting the UE to a delay-tolerant category according to a request from at least one of a network and a user; receiving a paging message including warning indication from a network; in response to the paging message, determining whether the warning indication is associated with a procedure for an Earthquake and Tsunami Warning service (ETWS) notification or a procedure for a Commercial Mobile Alert Service (CMAS) notification; determining whether the UE is currently set to the delay-tolerant category; if the UE is currently set to the delay-tolerant category, in response to the paging message, even before receiving the ETWS notification or the CMAS notification, starting a delay timer according to a timer value which is selected from among a first timer value and a second timer value different from the first timer value, wherein the first timer value is used when the warning indication is associated with the ETWS notification procedure, and wherein the second timer value is used when the warning indication is associated with the CMAS notification procedure; acquiring scheduling information included in a system information block type 1 (SIB1) indicating whether an additional system information block is present in system information; if the additional system information block is present in the system information, receiving an additional system information block according to the scheduling information, wherein the additional system information block is one of a SIB10, SIB11, and SIB 12; processing a warning notification message included in the additional system information block; determining whether the delay timer expires; and performing a random access procedure after the delay timer is expired if a session initiation request is triggered.