-2000 Voice Data Rate Changing Method in IMT-2000 Network

摘要

PURPOSE: A method for changing a voice data rate of an IMT-2000 network is provided to offer a QoS according to a radio environment by changing a vocoding rate as requested based on a change in the radio environment. CONSTITUTION: When a call setup request is received from a subscriber, a talking path is set among an RNC(Radio Network Controller), an MSC(Mobile Switching Center) and an IWU(Inter Working Unit)(S10). An IuUP(User Plane Protocol) between the RNC and the MSC and NbUP between the MSC and the IWU are initialized(S12,S14). A voice data with a highest rate value among various RFCI(Radio access bearer sub Flow Combination Indicator) values set during the initialization process is transmitted and received between the RNC/MSC/IWU(S16). If a radio section environment is changed, the RNC generates a UP-control frame requesting a vocoding rate change(S18,S20). The UP control frame is transmitted to an AAL2(ATM Adaptation Layer) processor of the IWU, and the AAL2 processor detects a UP-type 14 RC(Rate Control) frame(S22,S24). The AAL2 processor transfers the UP-type 14 RC frame to a vocoder through a different path from a voice path(S26). The vocoder checks a content of the UP type 14 RC frame and judges whether a vocoding rate to be changed is an acceptable rate in the vocoder(S28,S30). If the vocoding rate to be changed is an acceptable rate, the vocoder changes the vocoding rate, generates an ACK UP frame and transfers it to the AAL2 processor(S32). AAL2 processor converts the ACK UP frame into a UP-type 14 RC ACK/NAK frame, converts it into an ATM(Asynchronous Transfer Mode) cell and transfers it to the RNC(S36). The RNC and the IWU transmits and receives a voice data at the changed vocoding rate(S38).