KR100425982B1 - Voice Data Rate Changing Method in IMT-2000 Network - Google Patents

Abstract

The present invention relates to a method of changing a voice data rate of an IMT-2000 network to convert a voice data rate according to a wireless environment in an IMT-2000 network.

In the conventional IMT-2000 network, the RNC monitors the wireless environment and controls the vocoding rate according to the wireless environment. However, the RNC and the IWU perform vocoding at a fixed rate so that the QoS of the wireless environment cannot be provided in the ATM band. As a result, there is a problem that cannot use the ATM band efficiently.

The present invention applies a UP to request a change in the vocoding speed from the RNC to the vocoder of the IWU in accordance with the change in the wireless environment, and by changing the vocoding speed in response to the request of the RNC in the vocoder of the IWU to support the multi-rate QoS can be provided accordingly.

Description

Voice Data Rate Changing Method in IMT-2000 Network

The present invention relates to a method of changing the voice data rate of an IMT-2000 network, and more particularly, to a method of changing the voice data rate of an IMT-2000 network to convert the voice data rate according to a wireless environment.

1 is a road, a Radio Network Controller (RNC) 10, and a Serving Mobile Switching Center (SMSC) showing an exemplary configuration of an International Mobile Telecommunication (IMT) -2000 network proposed by a 3rd Generation Partnership Project (3GPP) ( 20) and a Gateway Mobile Switching Center (GMSC) 40.

In such a configuration, the RNC 10 is a system for matching mobile terminals, and exchanges signals and voice packets for voice communication with the mobile terminals.

The SMSC 20 is an MSC 30 that matches the RNC 10, and the GMSC 40 is an MSC 50 that matches the Public Switched Telephony Network (PSTN).

As described above, the MSCs 30 and 50 are configured as an Asynchronous Transfer Mode (ATM) switch to perform signal and traffic matching with the RNC 10 and other MSCs, and the Iu (Iu Reference Point) specification is different from the RNC 10. According to the Nb (Nb Reference Point) standard with other MSCs.

Meanwhile, in 3GPP, a voice coding method recommended for voice communication is defined as adaptive multi-rate (AMR).

Accordingly, the AMR voice packet generated in the mobile terminal is converted into an ATM cell through a segmentation and reassembly (SAR) process in the RNC 10, and after the ATM exchange process is performed in the SMSC 20 and the GMSC 40, the GMSC 40. IWU (Inter Working Unit) (60).

As described above, the IWU 60 converts the AMR code into a PCM code to match the PSTN, and routes the voice packet converted into the PCM code to the PSTN by an appropriate relay line signal.

In general, the AMR code is a vocoding scheme that supports multirate, and the RNC 10 monitors the wireless environment to control the vocoding rate from 0kbps to 12.2kbps according to the wireless environment. Thus, the mobile terminal determines the vocoding rate under the control of the RNC 10.

2 is a road for explaining a voice traffic transmission method in a conventional IMT-2000 network, the AMR voice packet generated in the mobile terminal is input to the RNC 10 through a wireless protocol, and receives the AMR voice packet from the mobile terminal. The RNC 10 converts an AMR voice packet into an ATM every 20 ms through an ATM Adaptation Layer (AAL2) SAR process.

The AAL2 ATM cell generated every 20 ms at the RNC 10 is inputted to the IWU 60, which is a PSTN matching element of the GMSC 40, via the SMSC 20 and the GMSC 40. The RNC 10 / SMSC ( 20) / GMSC 40 / IWU 60 matching is done via ATM signaling.

As described above, the AAL2 ATM cell input to the IWU 60 through ATM signaling is applied to the AAL2 processing unit 65 through the ATM (Traffic Management) suitable for voice processing by the ATM cell processing unit 63, and the AAL2 processing unit ( In step 65), an ATM SAR process is performed to output the AMR voice packet generated every 20 ms to the vocoder 67.

The AMR voice packet inputted to the vocoder 67 through the ATM SAR process by the AAL2 processing unit 65 is converted into the PCM, and then routed to the PSTN via the PSTN matching unit 69.

As described above, in the conventional IMT-2000 network, the RNC 10 monitors the wireless environment and controls the vocoding speed according to the wireless environment, but performs the vocoding at a fixed speed in the RNC 10 and the IWU 60. In the RNC 10 / SMSC 20 / GMSC 40 / IWU 60, AMR voice packet transmission is performed at a fixed rate.

Therefore, in the ATM band, it is not possible to provide a Quality of Service (QoS) according to a wireless environment, and there is a problem in that the ATM band cannot be efficiently used.

The present invention has been made to solve the above-described problem, by applying a UP request to change the vocoding speed from the RNC to the vocoder of the IWU in accordance with the change in the wireless environment, the vocoder of the IWU in accordance with the request of the RNC It is an object of the present invention to provide a method of changing the voice data rate of an IMT-2000 network that can provide QoS according to a wireless environment by changing and supporting multirate.

1 is a diagram illustrating the configuration of an IMT-2000 network proposed by 3GPP by way of example.

2 is a view for explaining a voice traffic transmission method in a conventional IMT-2000 network.

3 is a diagram illustrating a configuration of an IMT-2000 network to which a voice data rate changing method according to the present invention is applied.

4 to 6 are diagrams for explaining a voice data rate changing method of an IMT-2000 network according to the present invention.

*** Explanation of symbols for the main parts of the drawing ***

10.RNC, 20.SMSC, 30, 50.MSC,

40.GMSC, 60.IWU, 63. ATM cell processing unit,

65. AAL2 processing section, 67. Vocoder, 69. PSTN matching section

The voice data rate changing method of the IMT-2000 network according to the present invention for achieving the above object is to initialize the IuUP between the RNC and the MSC and the NbUP between the MSC and the IWU when a call path is established according to a call setup request. An initialization process; Transmitting and receiving voice data at the highest rate among the vocoding rates set in the initialization process; If it is necessary to change the vocoding rate due to a change in the wireless section environment, a vocoding rate change request process for requesting a vocoding rate change from the RNC to the vocoder of the IWU; And a vocoding rate changing process of changing the vocoding rate in the vocoder of the IWU according to the vocoding rate changing request, and transmitting and receiving voice data at the changed vocoding rate.

Here, the vocoding rate change request process may include: determining whether the vocoding rate should be changed due to a change in radio section environment in the RNC; If it is determined that the vocoding rate needs to be changed, generating a UP control frame requesting a vocoding rate change and transmitting the generated UP control frame to the AAL2 processor of the IWU; When the AAL2 processor detects an UP control frame requesting a vocoding rate change, the AAL2 processor transfers the detected UP control frame to a vocoder through a path other than a voice path.

The vocoding speed changing process may include: determining whether a vocoding speed that is changed is a speed that can be provided by a vocoder by checking the contents of the UP control frame in the vocoder; If the changed vocoding rate is a speed that can be provided by the vocoder, changing the vocoding rate according to a vocoding rate change request, and transmitting a response message to the vocoding rate change request to the AAL2 processor; Converting the response message into an UP control response message by the AAL2 processing unit, converting the response message into an ATM cell through an AAL2SAR process, and then transmitting the same to the RNC; And transmitting and receiving voice data at the changed vocoding rate.

Hereinafter, a voice data rate changing method of an IMT-2000 network according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

3 is provided with a road, an RNC 10, an SMSC 20, and a GMSC 40 showing the configuration of an IMT-2000 network to which a voice data rate changing method according to the present invention is applied.

In such a configuration, the RNC 10 exchanges an AMR voice packet received from the mobile terminal with an ATM cell by matching the mobile terminal with a signal for voice communication, and converts the converted ATM cell into an UP ( It transmits to the SMSC 20 by using the User Plane Protocol), converts the ATM cell received in the UP from the SMSC 20 into an AMR voice packet and transmits it to the mobile terminal.

The SMSC 20 switches the ATM cell received in the UP from the RNC 10 to the GMSC 40, and switches the ATM cell received in the UP from the GMSC 40 to the RNC 10.

The GMSC 40 switches the ATM cell received in the UP from the SMSC 20 to the IWU 60, and the MSC 50 switches the ATM cell received in the UP from the IWU 60 into the SMSC 20. It is provided with an IWU (60) converting the ATM cell received from the MSC (50) to the UP to the PCM to convert the PCM received from the PSTN to the ATM to transmit to the MSC (50) to the UP.

As described above, the IWU 60 performs an ATM SAR process on an ATM cell processor 63 for processing an AAL2 ATM cell inputted from the MSC 50 as UP and an AAL2 ATM cell authorized with UP from the ATM cell processor 63. AAL2 processor 65 for converting to AMR speech packet, vocoder 67 for converting AMR speech packet received from UP from AAL2 processor 65 to PCM, and PCM received from vocoder 67 to PSTN. And a PSTN matching section 69 for routing.

As described above, UP is implemented in each component of the IMT-2000 network to which the voice data rate changing method according to the present invention is applied. As described above, the MSC 30 includes the RNC 10 and the Iu standard. According to the Nb standard and the other MSC 50, the UP protocol applied between the MSC 30 and the RNC 10 is IuUP, and is applied between the MSC 30 and the MSC 50. The UP protocol is NbUP (see 3GPP TS25.415, 29.415).

As described above, when the UP protocol is used with an AMR code, UP initialization between the vocoder (not shown) of the RNC 10 and the vocoder 67 of the IWU 60, vocoder rate control, wireless It performs voice traffic delay, time alignment, and error control according to the environment.

Accordingly, in the present invention, when transmitting the AMR voice packet to the UP, the UP control message is also delivered to perform the above-described function.

In the UP, AMR voice traffic and the above-described control message are classified into types 0/1/14. Type 0 is an UP frame in which AMR voice packets are carried, and includes a CRC (CyclicRedundancy Check) for an AMR code. Is an UP frame carrying an AMR voice packet, does not include a CRC for an AMR code, and type 14 is an UP frame carrying a control message, and a control message can be classified into a process ID.

4 to 6 are diagrams for explaining a voice data rate changing method of an IMT-2000 network according to the present invention.

First, if there is a call setup request from the subscriber, a call path between the RNC 10, the MSCs 30 and 50, and the IWU 60 is established according to the call processing procedure (S10).

When the call path is established through the above-described process S10, in order to initialize the UP between the vocoder (not shown) of the RNC 10 and the vocoder 67 of the IWU 60, between the RNC 10 and the MSC 30. The process of initializing the NbUP between the IuUP and the MSC 50 and the IWU 60 is performed (S12 and S14).

In the initialization process of steps S12 and S14 described above, UP is activated to set variables for performing rate control (RC), time alignment (TA), and the like. For example, RFCI (Radio Access Bearer Sub Flow Combination Indicator) 0 is set to 12.2 kbps and RFCI 1 is set to 5.2 kbps so that the vocoding rate can be changed later according to the RFCI value.

Since the initialization of the IuUP and the NbUP should be performed independently according to the recommendation, the MSCs 30 and 50 perform arbitration by performing the UP of the RNC 10 / MSC 30 and the MSC 50 / IWU 60, respectively. Should be.

When the UP initialization between the vocoder (not shown) of the RNC 10 and the vocoder 67 of the IWU 60 is completed through the processes S12 and 14, the RNC 10 / MSC 30, 50 / IWU are completed. Between 60, voice data is transmitted and received by the AMR code to which the UP protocol is applied, and voice data is transmitted and received at a value having the highest speed among various RFCI values set during the initialization process (S16).

For example, if the RFCI0 is set to 12.2kbps and the RFCI1 is set to 5.2kbps in the initialization process of steps S12 and S14, voice data is transmitted and received according to a high RFCI0 (12.2kbps).

Subsequently, when the wireless section environment is changed and the vocoding speed of the UP is to be changed, the RC which changes the vocoding speed according to the wireless section environment should be activated. The RC process of the UP is performed by the vocoder (not shown) of the RNC 10. C) and the vocoder 67 of the IWU 60, and the MSCs 30 and 50 must bypass the RC packet of the UP between the RNC 10 and the IWU 60.

Type 0/1 packets (voice data packets) and type 14 packets (control packets) of the UP are classified into protocol data unit (PDU) types among the overheads of the UP, and the type 14 packets function as processing IDs (Initialization, RC, TA, EC).

As described above, when the vocoding speed of the UP is to be changed according to the change in the wireless section environment, the RC which changes the vocoding speed according to the wireless section environment should be activated. Will perform.

Therefore, when the wireless section environment changes to change the vocoding rate of the UP, the RNC 10 generates an UP control frame (IuUP type 14 RC frame) requesting the vocoding rate change by activating the RC ( S18, S20).

When the RNC 10 performs a vocoding rate change request to the vocoder 67 of the IWU 60 in step S20, it may perform a vocoding rate change request using the RFCI value set in the initialization process. .

For example, when the radio section environment is deteriorated and the RNC 10 needs to change the voice data rate from 12.2 kbps to 5.3 kbps, the RNC 10 activates RC to change the RFCI value to RFCIO (12.2 kbps). Generates an IuUP Type 14 RC frame that requires a change to RFCI1 (5.3kbps).

The UP control frame generated in step S20 is transmitted to the AAL2 processing unit 65 of the IWU 60 via the MSCs 30 and 50, and the AAL2 processing unit 65 of the IWU 60 is UP in the received frame. Type 14 RC frames are detected (S22, S24).

In step S24, the AAL2 processor 65 of the IWU 60 recognizes that the frame received through the AAL2 SAR process is an UP frame, and confirms that the received frame is an UP control frame by looking at the PDU type field of the UP frame. .

Confirm that the received frame is an UP control frame The AAL2 processor 65 recognizes that the corresponding UP control frame is an UP type 14 RC frame based on the process ID.

As described above, when the AAL2 processor 65 of the IWU 60 detects an UP type 14 RC frame (type 14 DET (RC)), the AAL2 processor 65 performs a voice path on the detected UP type 14 RC frame. Transfer to the vocoder 67 through a different path from (S26).

The vocoder 67, which has received the UP type 14 RC frame from the AAL2 processor 65 in step S26, checks the contents of the UP type 14 RC frame to determine whether the changed vocoding speed is a speed that can be provided by the vocoder 67. It determines (S28, S30).

When the vocoding speed that is changed as a result of the determination of step S30 is a speed that can be provided by the vocoder 67, the vocoding speed is changed according to the vocoding speed change request, and an affirmative response to the vocoding speed change request (ACK) A UP frame is generated and transmitted to the AAL2 processor 65 (S32).

On the other hand, when the vocoding speed that is changed as a result of the determination in step S30 is not a speed that can be provided by the vocoder 67, a negative response (NAK) indicating that the vocoding speed cannot be changed in response to the vocoding speed change request. A frame is generated and transmitted to the AAL2 processor 65 (S34).

The AAL2 processor 65 receiving the response UP frame from the vocoder 67 through step S32 or step S34 converts the response UP frame received from the vocoder 67 into an UP type 14 RC ACK / NAK frame, and then AAL2. After converting to an ATM cell through the SAR process, and then transmitted to the RNC 10 via the MSC (30, 50) (S36).

As described above, when the vocoder 67 of the IWU 60 changes the vocoding rate according to the vocoding rate change request, and sends a response to the RNC 10, the normal vocoding rate change is made. The RNC 10 and the IWU 60 transmit and receive voice data at the changed vocoding rate (S38).

For example, if the vocoder 67 of the IWU 60 wants to change the vocoding rate from RFCI0 (12.2 kbps) to RFCI1 (5.3 kbps) according to the vocoder (not shown) request of the RNC 10, If the voice data rate RFCI1 (5.3 kbps) is the speed that can be provided by the vocoder 67, the voice data rate is changed to RFCI1 (5.3 kbps) and the positive response UP frame is transmitted to the AAL2 processor 65.

As described above, when the vocoder 67 of the IWU 60 successfully changes the vocoding speed and transmits a response thereto, voice data transmitted and received at 12.2 kbps is transmitted and received at 5.3 kbps.

Subsequently, in the case where the wireless section environment is changed and the vocoding speed needs to be adjusted, steps S18 to S38 may be repeatedly performed.

The voice data rate changing method of the IMT-2000 network of the present invention is not limited to the above-described embodiment, and can be modified in various ways within the scope of the technical idea of the present invention.

According to the method of changing the voice data rate of the IMT-2000 network of the present invention as described above, the RNC requests a change in the vocoding rate from the RNC to the vocoder of the IWU according to the change of the wireless environment by applying UP, and the RNC By changing the vocoding rate according to the request to support multirate, it is possible to provide QoS according to the wireless environment.

Claims (3)

An initialization process of initializing the IuUP between the RNC and the MSC and the NbUP between the MSC and the IWU when the call path is established according to the call setup request; Transmitting and receiving voice data at the highest rate among the vocoding rates set in the initialization process; If it is necessary to change the vocoding rate due to a change in the wireless section environment, a vocoding rate change request process for requesting a vocoding rate change from the RNC to the vocoder of the IWU; And a vocoding rate changing process for changing the vocoding rate in the vocoder of the IWU according to the vocoding rate changing request and transmitting and receiving voice data at the changed vocoding rate. . The method of claim 1, wherein the vocoding rate change request process comprises: Determining, by the RNC, whether the vocoding speed should be changed due to a change in the wireless section environment; If it is determined that the vocoding rate needs to be changed, generating a UP control frame requesting a vocoding rate change and transmitting the generated UP control frame to the AAL2 processor of the IWU; When the AAL2 processor detects an UP control frame requesting a vocoding rate change, the AAL2 processor transmits the detected UP control frame to a vocoder through a path other than a voice path. How to change the data rate. The method of claim 1, wherein the vocoding speed changing process comprises: Determining whether the changed vocoding speed is a speed that can be provided by the vocoder by checking the contents of the UP control frame by the vocoder; If the changed vocoding rate is a speed that can be provided by the vocoder, changing the vocoding rate according to a vocoding rate change request, and transmitting a response message to the vocoding rate change request to the AAL2 processor; Converting the response message into an UP control response message by the AAL2 processing unit, converting the response message into an ATM cell through an AAL2 SAR process, and then transmitting the same to the RNC; And transmitting and receiving voice data at the changed vocoding rate.