g ftp in the network nt 3 and initiating a cs service via a cs fallback procedure the ue received a rrc connection release message or a mobility from eutra message to redirect the ue to a current network nt 4 the network nt 3 could be the target network 14 in the wireless communication system 10 which supports both of cs domain and ps domain the ue camps on the network nt 4 and initiates a rrc connection procedure for the cs service the process 50 can be compiled into the program code 214 and include the following steps step 502 the ue includes a specific cause in a rrc connection request message m 3 when moving from the network nt 3 e g e utran or gsm to the network nt 4 e g utran step 504 the ue sends the rrc connection request message m 3 to the network nt 4 for rrc connection establishment step 506 the network nt 4 receives the rrc connection request message m 3 from the ue step 508 the network nt 4 does not redirect the ue to the network nt 3 according to the specific cause according to the process 50 when the ue is redirected from the network nt 3 to the network nt 4 the ue includes the specific cause in the rrc connection request message m 3 then the ue send the rrc connection request message m 3 to the network nt 4 for rrc connection establishment the network nt 4 receives the rrc connection request message m 3 from the ue according to the specific cause the network nt 4 does not redirect the ue the network nt 3 in other words the ue perform.