CN100461663C - A method for determining codec type - Google Patents

Abstract

The invention discloses a codec type determination method, which is used to solve the problem in the prior art that the service quality cannot be guaranteed due to the inability to dynamically select the appropriate codec type according to the change of the link quality. The invention detects the office-direction link quality of the media gateway by sending sampling calls, judges the change of the office-direction link quality, and determines the corresponding preferred codec type for the call sent upward in the office. Therefore, it is simple and easy to realize that the appropriate codec type can be selected for the call according to the change of the link quality. When the link quality improves, it can provide users with excellent service quality; when the link quality decreases, it can provide users with Acceptable quality of service. In this way, a better communication experience can be provided for users, and user satisfaction can be improved.

Description

A method for determining codec type

technical field

The invention relates to the next generation network technology, in particular to a codec type determination method in the next generation network.

Background technique

The Next Generation Network (NGN, Next Generation Network) system is a business convergence network that uses the IP network as the bearer and provides multiple services such as fixed and mobile voice, data and video. Its basic feature is the separation of control, bearer and business.

In the NGN system, the traditional switch is separated into two network elements, MGC (Media Gateway Controller, Media Gateway Controller) and MG (Media Gateway, Media Gateway). The MGC is mainly used to complete the function of the call control layer; while the MG is mainly used to complete the media stream processing and bearer processing functions. The MG can convert different types of access signals into data suitable for transmission on the IP (Internet Protocol, Internet Protocol) network RTP/RTCP (Real Time Protocol/Real Time Control Protocol, Real Time Protocol/Real Time Control Protocol) stream. The MGC usually uses a gateway control protocol to control the MG, where the gateway control protocol includes but is not limited to the H.248 protocol and MGCP (MediaGateway Control Protocol, Media Gateway Control Protocol).

In the existing NGN system, the MGC of the calling party is usually responsible for completing the codec optimization and negotiation of an IP call. The process is as follows:

The MGC of the calling party obtains the support of the MG through configuration or audit (configuration refers to the capability information of the MG controlled by the MGC configured by the user on the MGC, and audit refers to the status, configuration and capability information obtained by the MGC through the audit command in the gateway control protocol). For all codec types, the codec types are sorted according to the priority order, and the codec type that the MGC most wants to use is ranked first, and the MGC sends the sorted codec type list to the call processing entity of the called party , such as MGC, SIP (Session Initiation Protocol, Session Initiation Protocol) gateway, etc., the call processing entity of the called party deletes the codec types that it does not support in the codec type list according to the ones supported by itself, and in the remaining codec types Select one and reply to the calling party's MGC. Since the codec type list sent by the MGC of the calling party to the called party has been sorted according to the order of priority, the called party generally selects the codec type supported by itself from the codec type with the highest priority in the list.

In the prior art, the priority order of the codec types in the list of codec types supported by the MG is usually a fixed order pre-configured on the MGC. When the calling party MG needs to make a call, the MGC will use the fixed order The list is sent to the call processing entity of the called party, and the codec type of the call is determined through negotiation with the call processing entity of the called party. Since the MGC of the calling party sends out the same codec type list each time during the codec type negotiation, the codec type used for each call with the same calling party and the called party is the same. When the link quality between called parties changes, the codec type cannot be dynamically selected to adapt to the link quality change. When the link quality drops, the codec type with lower link quality requirements cannot be preferred to provide users with acceptable call quality; when the link quality improves, the codec type with higher link quality requirements cannot be preferred , to provide users with excellent call quality, so that the quality of service cannot be effectively guaranteed.

Contents of the invention

The present invention provides a method for determining a codec type, which is used to solve the problem in the prior art that the service quality cannot be guaranteed due to the inability to dynamically select an appropriate codec type according to changes in link quality.

The inventive method comprises:

A codec type determination method, comprising the steps of:

Detect the quality of the office link of the media gateway by sending sampling calls, and judge the change of the link quality of the office;

Determine the corresponding preferred codec type for the call sent on the office according to the change of the link quality of the office.

The office direction is a connection path between the media gateway and other gateways, or a common connection path between the media gateway and all terminals under the same IP network segment.

The link quality change is judged by establishing a link index, comparing the local link quality detection result of the media gateway with a predetermined link quality threshold, and increasing the link index value when it is higher than the threshold, otherwise Decrease the link index value.

When the media gateway has multiple office directions, a corresponding link index is established for each office direction and the identification information corresponding to each office direction is saved.

The correspondence between the link index and its applicable preferred codec type is preset.

The sample call is a real call and/or a test call.

The office direction of the media gateway is an office direction preconfigured during network planning and/or an office direction added by automatic identification from a call.

The preferred codec type includes several codec types sorted by priority, and the codec type with the highest priority is used for calling first.

The beneficial effects of the present invention are as follows:

The present invention detects the office link quality of the media gateway by sending sampled calls, and determines the corresponding preferred codec type for the call according to the change of the link quality, so that it is simple and easy to implement the link quality change as Selecting the appropriate codec type for the call can provide users with excellent service quality when the link quality is improved; when the link quality is degraded, it can provide users with acceptable service quality. In this way, a better communication experience can be provided for users, and user satisfaction can be improved.

Description of drawings

Fig. 1 is the flow chart of codec type determination of the present invention;

Figure 2 is a schematic diagram of the office direction of the media gateway;

Figure 3 is a flow chart of determining the preferred codec type by the MGC;

Fig. 4 is a flow chart of determining the preferred codec type by the MG.

Detailed ways

The method for determining the codec type in the present invention aims at the defects of the prior art, and proposes a processing method that can select the corresponding preferred codec type for the call according to the change of the link quality. The specific embodiment is described in detail.

The method of the invention is suitable for selecting codec types for various types of calls issued by media gateways in the NGN system.

Fig. 1 shows the flowchart of determining the preferred codec type of the present invention, and its main implementation process is as follows:

Step S1, generate an office direction, which is the IP connection path between the MG and other gateways, or the common connection path between the MG and all terminals under the same IP network segment; the generation of the office direction can be pre-configured during network planning , you can also use the method of automatically identifying and adding office directions from the call, and further, you can use a combination of the two methods;

Figure 2 is a schematic diagram of the office directions of the media gateways. Each MG has one or more office directions. Among them, office direction 1 is the gateway with the same IP connection path to the MG, and office direction 2 is the gateway with the same IP connection path to the MG. All IP terminals under one IP network segment.

Step S2, the local MG performs office-to-office link quality detection through the office-up sampling call, and the peer uses the RTCP sending and receiving message monitoring function to perform statistics on the data packets received by itself at predetermined intervals to obtain the packet loss rate , network delay, jitter and other QoS (Quality of Service) parameters, and notify the local MG of the obtained QoS parameters through RTCP, and the local MG determines the link quality parameters used to characterize the link quality according to the QoS parameters . .

Step S3, establishing a corresponding link index for each office direction of the MG, which is used to represent the link quality change of the office direction, and the identification information of the office direction corresponding to the link index is stored in the form of a correspondence table;

When the link quality parameter corresponding to the sampled call reaches the predetermined link quality threshold, the link index value is increased by a preset increment; when the link quality parameter is smaller than the predetermined link quality threshold, the link index value is increased by The preset decrement amount decreases, and when the link index value is decremented to the initial value of the link index, the decrement will not continue.

Step S4: Determine the preferred codec type for the call according to the correspondence between the preset link index and the preferred codec type. There are usually multiple preferred codec types, and sort these codecs according to their priority. Ensures that higher priority codecs are used first for calls.

The above-mentioned process of determining the preferred codec type can be completed by the MGC or the MG, and the implementation process will be described respectively below.

Figure 3 shows the flow chart of the MGC determining the preferred codec type, and its main implementation process is as follows:

Step S11: Generate each office direction of the MG on the MGC. The generation of the office direction can be performed by pre-configuring each office direction of the MG on the MGC during network planning, or by automatically identifying and adding the office direction from the call by the MGC. way, further, a combination of two ways can be used. For example, the MGC pre-configures the office direction corresponding to the gateway connected to the MG during network planning. During operation, whenever the MGC finds that a call with a new destination IP An office route is automatically added to the MGC. Because there are generally a large number of IP terminal devices in the NGN network, if the method of automatically generating office directions is used, the MGC should have the function of converging office directions.

Step S12, the MGC sends a sampling call, and instructs the MG to perform link quality detection on the sampling call through a gateway control protocol (such as H.248 protocol, MGCP) or a proprietary protocol;

When the peer device in the office direction supports test calls, the MGC needs to maintain a predetermined number of sampling calls for the office direction at the same time. The MGC uses real calls as the sampling calls first. If the number of real calls in each office direction reaches the predetermined value, Select a call with a predetermined value from the real calls as a sample call; otherwise, the MGC sends a test call to supplement the number of sample calls, so that the number of sample calls is equal to the predetermined value.

If the peer device in the office direction does not support the test call, the MGC uses the real call as the sample call.

The MGC instructs the MG to check the link quality of the sampling call. The peer device in the office direction checks the data packets received by itself every predetermined period of time, and uses the RTCP sending and receiving message monitoring function to collect statistics on the packet loss rate and network delay. , jitter and other QoS (Quality of Service) parameters, and notify the MG of the QoS parameters through RTCP, and the MG determines the link quality parameters used to characterize the link quality according to the QoS parameters. For example, the MG can pre-set corresponding weights for different QoS parameters according to different requirements of different call types on link quality, such as setting corresponding weights for different delay values, setting corresponding weights for different jitter values, and setting corresponding weights for different QoS parameters. When the MG receives the QoS parameters returned by the office, it searches for the weights corresponding to different QoS parameters, and adds up the weights to obtain the link used to represent the quality of the current link. road quality parameters.

In step S13, the MGC establishes a corresponding link index for each office of all MGs under its control, which is used to represent the link quality change of the office.

The MG compares the link quality parameter obtained in step S12 with the predetermined link quality threshold, and when the link quality parameter reaches the predetermined link quality threshold, the MG sends a link alarm to the MGC through the gateway control protocol or private protocol information, the MGC increases the link index value with a preset incremental control, and when the link quality parameter is less than the predetermined link quality threshold, the MG sends a link recovery message to the MGC through the gateway control protocol or a private protocol, and the MGC The set decrement control decreases the link index value. When the link index value is decremented to the initial value of the link index, it will not continue to decrement. For example, if the initial value of the link index of the office direction is set to 0, the MGC will add 1 to the link index value of the corresponding office direction every time it receives a link quality alarm, and will correspondingly The link index value of the local direction is decremented by 1, and when the link index value decrements to 0, it does not continue to decrement.

The link index of each office direction of the MG under the control of the MGC corresponds to the identification information of each office direction, and the corresponding relationship is stored in the database of the MGC. For example, two MGs are controlled under the MGC, numbered 1 and 2 respectively. The MG numbered 1 has three office directions, and the MG numbered 2 has two office directions. The corresponding relationship of the link index of the direction is:

Step S14. The MGC determines the preferred codec type for the call according to the preset correspondence between the link index and the preferred codec type. The correspondence between the MG's local link index and the preferred codec type is pre-recorded in the MGC in the database;

The link index value is used to represent the link quality change in the local direction. Different preferred codec types should be determined according to the link index value. There are usually multiple preset preferred codec types, and the first It is the codec type with the highest priority. For example, several link index range values may be set, and each link index range value corresponds to a group of preferred codec types. When the link index value is low, the preferred codec type is a type with better voice quality but more bandwidth, such as G.722.1 codec, G.711 codec, or even MP3, WMA codec, etc.; When the road index value is high, the preferred codec type is a codec type with slightly poorer voice quality but less bandwidth occupation, such as G.729 codec, G.723.1 codec, G.729 codec, G.726 codec etc., or restrict calls to this office.

The following table shows the correspondence between the link index and the preferred codec type set by the MGC in advance for the MG with two office directions:

The MGC determines the preferred codec type for the call based on the current link index value, and passes the determined preferred codec type through inter-office signaling, such as BICC (Bearer Independent Call Control Protocol, bearer-independent call control protocol) or SIP (Session Initiation Protocol, Session Initiation Protocol) is sent to the peer end of the office direction.

Step S15, the call processing entity at the opposite end receives the preferred codec type, deletes the codec types that it does not support in the preferred codec types, and selects one of the remaining codec types, and the call processing entity at the opposite end generally selects the preferred codec type The codec type with the highest level begins to select the codec type supported by itself, and returns the selected codec type to the MGC, and the MGC instructs the MG to perform codec operations on the call according to the returned codec type.

Figure 4 shows the flow chart for the MG to determine the preferred codec type, and its main implementation process is as follows:

Step S21. Generate each office direction of the MG on the MG. The generation of the office direction can be performed by pre-configuring each office direction on the MG during network planning, or by automatically identifying and adding the office direction from the call by the MG. , further, a combination of the two methods can be used. For example, during network planning, the office route corresponding to the gateway with which it is connected is pre-configured on the MG. During operation, whenever a call with a new destination IP address occurs on the MG, an office route is automatically added. Because there are generally a large number of IP terminal devices in the NGN network, if the method of automatically generating office directions is used, the MG should have the function of converging office directions.

Step S22. The MG performs link quality detection on the real call sent by the MGC. The peer device in the office direction detects the data packets received by itself every predetermined time interval, and uses the packet loss rate of RTCP to monitor the function of sending and receiving packets. , network delay, jitter and other QoS (Quality of Service) parameters, and notify the MG of the QoS parameters through RTCP, and the MG determines the link quality parameters used to represent the link quality according to the QoS parameters.

For example, the MG can pre-set corresponding weights for different QoS parameters according to different requirements of different call types on link quality, such as setting corresponding weights for different delay values, setting corresponding weights for different jitter values, and setting corresponding weights for different QoS parameters. When the MG receives the QoS parameters returned by the office, it searches for the weights corresponding to different QoS parameters, and adds up the weights to obtain the link used to represent the quality of the current link. road quality parameters.

In step S23, the MG establishes a corresponding link index for each office direction, which is used to represent the link quality change of the office direction.

The MG compares the link quality parameter obtained in step S12 with a predetermined link quality threshold, and when the link quality parameter is greater than or equal to the predetermined link quality threshold, increases the link index value by a preset increment , when the link quality parameter is less than a predetermined link quality threshold, the link index value is controlled to decrease by a preset decrement amount. When the link index value is decremented to the initial value of the link index, it will not continue to decrement.

For example: set the initial value of the link index of the office direction to 0. When the link quality parameter is greater than or equal to the link quality threshold, the MG will add 1 to the link index value of the corresponding office direction. When the link quality threshold is reached, the MG will decrease the link index value of the corresponding local direction by 1, and when the link index value decreases to 0, it will not continue to decrease.

The link index of each office direction of the MG corresponds to the identification information of each office direction, and the corresponding relationship is stored in the database of the MG. For example, the correspondence relationship between the office identification information of an MG with three office directions and the link index of the office direction is:

Office route identification information link index 1 2 2 0 3 6

Step S24, the MG determines the preferred codec type for the call according to the preset correspondence between the link index and the preferred codec type, and the correspondence between the MG's local link index and the preferred codec type is pre-recorded in the MG in the database;

The link index value is used to represent the link quality change in the local direction. Different preferred codec types should be determined according to the link index value. There are usually multiple preset preferred codec types, and the first It is the codec type with the highest priority. For example, several link index range values may be set, and each link index range value corresponds to a group of preferred codec types. When the link index value is low, the preferred codec type is a type with better voice quality but more bandwidth, such as G.722.1 codec, G.711 codec, or even MP3, WMA codec, etc.; When the road index value is high, the preferred codec type is a codec type with slightly poorer voice quality but less bandwidth occupation, such as G.729 codec, G.723.1 codec, G.729 codec, G.726 codec etc., or restrict calls to this office.

The following table shows the correspondence between the link index and the preferred codec type set by the MG with two office directions:

The MG determines the preferred codec type for the call according to the current link index value, and sends the determined preferred codec type to the MGC through a gateway control protocol (such as H.248 protocol, MGCP) or a private protocol, and the MGC communicates with the inter-office Signaling, such as BICC (Bearer Independent Call Control Protocol, bearer-independent call control protocol) or SIP (Session Initiation Protocol, session initiation protocol) is sent to the peer end of the office direction.

Step S25, the call processing entity at the opposite end receives the preferred codec type, deletes the codec types that it does not support in the preferred codec types, and selects one of the remaining codec types, and the call processing entity at the opposite end generally selects the preferred codec type The codec type with the highest level begins to select the codec type supported by itself, and returns the selected codec type to the MGC, and the MGC instructs the MG to perform codec operations on the call according to the returned codec type.

It can be seen that the codec type determination method of the present invention can select an appropriate codec type for a call according to the change trend of the link quality, and can provide users with excellent service quality when the link quality is good; When the road quality is poor, it can provide users with acceptable service quality, thereby providing users with a better communication experience and improving user satisfaction.

Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and variations.

Claims (8)

1. a code/decode type is determined method, it is characterized in that, comprises step:

By sending the office direction link-quality of sampling calling detection media gateway, judge the change in link quality situation of this office direction;

Change in link quality situation according to office direction is determined corresponding optimizing code and decode type for the calling that sends on this office direction.

2. the method for claim 1 is characterized in that, described office direction is the access path between media gateway and other gateways, or the common access path of all terminals under media gateway and the same IP network section.

3. the method for claim 1, it is characterized in that, described change in link quality situation is judged by setting up the link index, the office direction link-quality testing result of media gateway is compared with the link-quality threshold value of being scheduled to, when being higher than described threshold value, increase the link exponential quantity, otherwise reduce the link exponential quantity.

4. method as claimed in claim 3 is characterized in that, when described media gateway has a plurality of office direction, sets up the identification information of link corresponding index and corresponding each office direction for each office direction respectively and preserves.

5. as claim 3 or 4 described methods, it is characterized in that, set in advance the corresponding relation between described link index and its optimizing code and decode type that is suitable for.

6. the method for claim 1 is characterized in that, described sampling is called out to true and called out and/or test call.

7. the method for claim 1 is characterized in that, when the office direction of described media gateway is the network planning pre-configured office direction and/or from call out the identification office direction of adding automatically.

8. the method for claim 1 is characterized in that, comprises the code/decode type that several according to priority just sort in the described optimizing code and decode type, and the code/decode type that its medium priority is the highest preferentially is used for calling out.

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