JP3126956B2 - Communication service quality control method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention determines the quality of service in a resource for realizing a communication service in its own terminal device when communicating with a partner terminal device connected via a network. The present invention relates to a communication service quality control method and apparatus for controlling communication to be performed according to the quality of service.

[0002]

2. Description of the Related Art In recent years, multimedia mobile communication using a portable information terminal and wireless communication has become widespread. Generally, wireless communication has a feature that an available band is narrower than a wired communication and a transmission error rate is high, and the band and the error rate dynamically fluctuate with the movement or time of a terminal. Therefore, the quality of service (Quality) is adaptively compensated for the dynamically changing wireless communication environment by filling the difference between the wireless and wired communication environments.
of Service: Hereinafter, referred to as QoS. Is important.

[0003] Prior art document 1 "Elan Amir"
Amir), “An Application Level Video Gateway”, P
"roceedings of ACM Multimedia, 1995" proposes a video gateway (hereinafter, referred to as a first conventional example) for converting a moving image encoding method between two heterogeneous communication networks. The main purpose of the video gateway of the first conventional example is to match the amount of transmission data of a moving image to a communication band by encoding system conversion.

[0004] Prior art document 2 "Y. Takasima" et al., "Reversible variable length code (Rev.
ersible Variable Length Codes) ”, IEEE Transactio
ns on Communications, Vol. 43, No. 2/3/4, February / March / April 1995 ”, a reversible variable-length code (hereinafter referred to as a second conventional technique) is one of the typical error resilience techniques. It is called an example.)
Has been proposed. According to the second conventional example, when an error occurs in received data, it is possible to reversely decode data after the error occurrence point, which normally had to be partially discarded, so that error resilience is reduced. Is strengthened.

[0005]

However, the first conventional example does not consider the difference in error characteristics between heterogeneous communication networks and an error resilience control mechanism for coping with the difference.
Further, in the second conventional example, the code amount increases more than usual due to the redundancy of the coding, and when RVLC is applied in the intermediate server, it is necessary to consider a compensation mechanism for this code amount increase. The point is outside the range of the second conventional example.

[0006] In multimedia mobile communication in which wireless and wired communication environments coexist, another problem is how to bridge the difference in quality between wireless communication and wired communication to achieve seamless communication.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and to improve the QoS of an application that provides a communication service based on the fluctuation of QoS in a network or a communication terminal.
It is an object of the present invention to provide a communication service control method and apparatus capable of dynamically and adaptively controlling the communication service.

[0008]

A communication service quality control method according to a first aspect of the present invention includes communication control means for controlling the quality of communication service between a plurality of terminal devices connected via a network. In the communication service quality control method for a terminal device, detecting and outputting the resource information of the terminal device realizing the communication service and the resource information of the network, and changing the service quality of the communication service application from one terminal device When the request signal is received, after performing a predetermined error resilience control process based on the detected resource information, using the mapping method of converting the service quality of the application to the service quality of the resource, the request signal is indicated by the request signal. The quality of service of the resources required to perform the quality of service of the application Calculate, calculate the re-encoding parameter of the received data based on the calculated quality of service of the resource, and re-encode the received data with the calculated re-encoding parameter to the terminal device that transmitted the request signal Adaptively controlling the service quality of the application by transmitting and, based on the service quality of the application of the change request from the terminal device that transmitted the request signal, indicated by the change request using the mapping method Calculate the service quality of the resources required to perform the service quality of the application, calculate the re-encoding parameters of the received data based on the calculated service quality of the resources, and receive with the calculated re-encoding parameters By re-encoding the transmitted data and transmitting the request signal to the terminal device that transmitted the request signal. Characterized in that it comprises adaptively controlling the quality of service application.

[0009]

Further, the communication service quality control method according to claim 2 is the communication service quality control method according to claim 1, wherein the error resilience control processing includes a coding error resilience control method on a communication path and an information source. It is characterized by being executed using a combination of the coding error resilience control method.

According to a third aspect of the present invention, there is provided a communication service quality control device for a terminal device, comprising a communication control means for controlling the quality of communication service between a plurality of terminal devices connected via a network. The quality control device includes a detection unit that detects and outputs resource information of a terminal device that realizes a communication service and resource information of a network, and the communication control unit detects a service quality of a communication service application from one terminal device. Upon receiving the request signal to be changed, after performing a predetermined error resilience control process based on the detected resource information, using a mapping method for converting the service quality of the application to the service quality of the resource, the request signal Resources required to perform the indicated quality of service of the application. Calculating the service quality, calculating the re-encoding parameter of the received data based on the calculated service quality of the resource, re-encoding the received data with the calculated re-encoding parameter and transmitting the request signal. Adaptively controlling the service quality of the application by transmitting to the terminal device, the communication control means,
Based on the service quality of the application of the change request from the terminal device that transmitted the request signal, the service quality of the resource required to execute the service quality of the application indicated by the change request is calculated using the mapping method. Calculating a re-encoding parameter of the received data based on the calculated quality of service of the resource, and re-encoding the received data with the calculated re-encoding parameter and transmitting the request signal to the terminal device that transmitted the request signal By doing so, the service quality of the application is adaptively controlled.

[0012]

The communication service quality control device according to a fourth aspect of the present invention is the communication service quality control device according to the third aspect, wherein the error resilience control processing includes a coding error resilience control method on a communication path, and an information source. It is characterized by being executed using a combination of the coding error resilience control method.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment according to the present invention.
Communication Coordi server
nation Server: Hereinafter, referred to as CCS. FIG. 1 is a block diagram showing a moving image communication system on a network having a wireless communication network and a wired communication network, which includes 10).
In the moving image communication system of the present embodiment, for example, moving image data is
A case will be described in which transmission is performed to a mobile personal computer (hereinafter, referred to as a mobile PC) 32 via a network (hereinafter, also referred to as NE) 20, such as an N line, the Internet, or a LAN, the CCS 10, and a wireless base station device 31. CCS10 of the video communication system
, The resource monitoring unit 61 performs terminal resource information such as a CPU usage rate of the CPU 70 for realizing moving image communication, and network resources such as a transmission band and a bit error rate (BER) in the network 20 detected by the network transceiver 50. The information is monitored and output to the QoS control unit 60. In the present embodiment, the QoS control unit 60 receives the application QoS request and the QoS change policy from the mobile PC 32 (here, the QoS change policy refers to a specific QoS specification parameter desired by the user). At this time, as shown in FIG. 2, based on the terminal resource information and the network resource information detected by the resource monitoring unit 61, a known error correction coding scheme (Fo
rward Error Correction: Hereinafter, FEC. ) And automatic retransmission request method (Automatic Repeat Request: A
It is called RQ. ) And / or coding error resilience control processing in a communication path such as H.264. 263, MPEG-4, etc., it is determined whether an error resilience control process including an error resilience control process is necessary, and when it is determined that the error resilience control process is performed, the error resilience control process is executed. Calculate the QoS of the resources required to execute the application QoS by the QoS mapping method, calculate the re-encoding parameters of the received moving image data based on the calculated resource QoS, and calculate the re-encoding parameters with the calculated re-encoding parameters. The received moving image data is re-encoded and the mobile PC 32
It is characterized by being transmitted to.

As shown in FIG. 1, on a network 20, a video server device 30 for storing and supplying moving image data and a personal computer (hereinafter, referred to as a PC) 11 and a workstation (hereinafter, referred to as a PC) 11 serving as clients thereof. , WS.) 12, a wireless base station device 31 for performing wireless communication with a mobile PC 32 as a client, and a CCS 10 for controlling QoS in moving image communication with the mobile PC 32, for example.
Client PC11, WS12 and mobile P
Each of the C32s receives moving image data from the video server device 30 via the network 20 and displays the data on a CRT display. Here, in the present embodiment, the QoS control processing in the CCS 10 will be described for a moving image medium which is considered to be important in multimedia communication in the future, but not only moving image data but also still image data,
Multimedia data such as voice data and text data may be targeted.

[0017] Considering the case where a moving image transmitting terminal on a wired environment transmits a compression-encoded moving image stream to a mobile terminal on a wireless environment, a wireless environment generally has a narrower bandwidth than a wired environment. , And has a feature of a high transmission error rate, and there is a gap between the QoS provided by the two. Further, since the wireless environment dynamically fluctuates, processing depending on the situation at that time is required. In particular, compensating for a transmission error in a wireless path having a high transmission error rate is important for improving user convenience. Therefore, in an embodiment according to the present invention, a CCS having an error resilience control function combining an encoding technique in a communication channel and an encoding technique in an information source is provided.
10 is provided. Further, the CCS 10 of the present embodiment includes:
It also provides a function of monitoring the resource status of a network or a terminal and adaptively converting the QoS of a moving image stream in consideration of the redundancy and the like of the error resilience technology. As described above, the CCS 10 according to the embodiment of the present invention is characterized in that the error resilience technology and the QoS conversion are linked to perform the fine QoS adjustment according to the communication status and the user's request.

The CCS 10 is provided on a wired network such as a network 20 as shown in FIG.
Video server device 30 as a high-performance fixed terminal, and mobile PC 32 as a portable information terminal on a wireless network
Mediates communication with The functions of CCS10 include:
This includes (1) caching (temporary storage processing), (2) QoS conversion, and (3) enhancement of error resilience.

FIG. 2 is a diagram showing each function of the CCS 10 of FIG. The CCS 10 receives, from the user via the mobile PC 32, a request for a QoS of moving image data, and information from the network transceiver 50 and the CPU 70, information on the QoS fluctuation of the network or the terminal. CCS10
Dynamically controls error resilience of moving image data according to resource information of a network or a terminal. As shown in FIG. 2, the error resilience control process is selectively used from known FEC, ARQ, and the like as a coding error resilience control technology in a communication channel, and is implemented as an international standard as a coding error resilience control technology in an information source. Telecommunication Union Telecommunication Standardization Sector (Int
ernational Telecommunication Union-Telecommunicati
ons sector: Hereafter referred to as ITU-T. ) Recommendation H. 2
63 and the International Organization fo
r Standardization: Hereinafter, referred to as ISO. MP by
This is performed by selectively using the error resilience function from EG-4 or the like. The inconsistency between the amount of available resources and the amount of moving image data that occurs at that time is compensated for by the QoS conversion control of the moving image. The QoS conversion control of a moving image is performed according to a QoS request or a QoS conversion policy specified by a user.
This is realized by changing a moving picture coding method or a coding parameter in CS10.

At present, the ITU-T has adopted H.264 as an international standard for video coding for low bit rates. H.263 is recommended, and ISO standardization work is underway for MPEG-4. Some of the error countermeasure functions proposed there are slice mode (H.263), segment independent decoding mode (H.263), so-called NE.
WPRED (H.263), marker for resynchronization (MPEG
-4), data partitioning (MPEG-4),
Reversible Variable Length Code
Codes: Hereinafter, RVLC. ) (MPEG-4).

In the CCS 10 of the present embodiment, the above-described error resilience method is used in combination with a coding error resilience control technique in a communication path such as FEC or ARQ depending on the communication environment. For example, if the error rate is high, RVLC and FE
The error recovery function is enhanced by using C in combination. At this time, a substantial decrease in the transmission band due to the error control code is dealt with by reducing the amount of media information such as moving image data by the QoS conversion processing in the CCS 10. As a coding error resilience control technique in an information source, NEWPR for switching a reference frame is used.
Even when the ED is used, the effect of NEWPRED can be enhanced by increasing the number of reference frames temporarily stored in the mobile PC 32 as the receiving terminal by the QoS conversion processing in the CCS 10.

FIG. 3 is a block diagram illustrating the CCS 10 of FIG. 1 in more detail. The CCS 10 includes a network transceiver 50, a video decoding unit 51, a video re-encoding unit 52, a QoS control unit 60, a resource monitoring unit 61, a CPU 70, a mapping table memory 81, a boundary condition memory 82, and a spline coefficient memory 83. . The network transceiver 50 is a mobile PC 3
2 via the network 20 and sends the QoS request or QoS change policy to the QoS control unit 60,
In addition, it receives moving image data from the video server device 30 and transmits it to the moving image decoding unit 51. The network transceiver 50 further transmits the moving image data re-encoded by the moving image re-encoding unit 52 to the mobile PC 32 via the network 20.

The resource monitoring unit 61 monitors the status of resources of networks and terminals such as the network 20 and the mobile PC 32, and obtains current resource information. Here, the resource information includes resource information of a network (the network 20, and a wireless communication network between the wireless base station device 31 and the mobile PC 32), and resource information of a terminal (the mobile PC 32 and the CCS 10). The resource information of the network includes a required bandwidth represented by an average data amount (bps) transmitted from the video server device 30 to the mobile PC 32 per second, and a ratio (BER) of error bits within a predetermined time. The terminal resource information is the CPU usage rate and the memory usage rate in the mobile PC 32, and the resource information of the CCS 10 is the usage rate of the CPU 70. These are the resources Qo
Defined as S.

The QoS control unit 60 selects a coding error resilience control technique for a communication path and a coding error resilience control technique for an information source, if necessary, based on a QoS request or a QoS change policy from the mobile PC 32. And QoS conversion (mapping) processing to determine a resource QoS required to satisfy the QoS requirement. In the error resilience control technique, various error resilience techniques are selected according to a situation, or error resilience control for a medium is performed by changing a parameter. As a coding error resilience technique in an information source of a moving image medium, a known H.264 method is known. 263
, MPEG-4, etc., and the CCS 10 selectively uses error resilience techniques, such as NEWPRED and RVLC, proposed there. The QoS control unit 60 receives the QoS request or the QoS change policy from the mobile PC 32, and, based on the resource status monitored by the resource monitoring unit 61 and the selected error resilience technology,
Resource QoS that can satisfy user request QoS
Is determined using a mapping process, and the moving image re-encoding unit 5
Send to 2. If the resource QoS that satisfies the user request QoS cannot be realized, the QoS control unit 60 requests the user to change the application QoS and the QoS change policy.

Here, application QoS and user request QoS (or QoS request) will be described. Three parameters of a frame size, a frame rate, and a quantization coefficient are used as parameters for determining the quality of service of moving image communication, and these are collectively defined as application QoS, and the application QoS determines the quality of communication service. Parameters that can be taken are defined in advance, and the user-requested QoS refers to specific parameter values given by the user in a range that satisfies the definition set value of the application QoS. Here, the frame size is the number of pixels in one frame (the number of horizontal pixels ×
(Vertical number of pixels). The frame rate is the number of frames displayed in one second and is a natural number, and the larger the value, the smoother the motion of the object in the moving image. The quantization coefficient is a parameter related to the quantization step width used in the motion JPEG encoding, and takes an integer value of 1 to 100. The smaller the parameter value of the quantization coefficient, the larger the quantization step width and the smaller the data amount of the compressed moving image. However, in some cases, blurring or discoloration occurs, and the user's subjective evaluation decreases.

Here, RVLC, one of the coding error resilience control techniques in the information source performed in the QoS control section 60, will be briefly described. 4A and 4B are diagrams illustrating a normal variable length code and RVLC. FIG. 4A is a diagram illustrating a normal variable length code, and FIG. 4B is a diagram illustrating an RVLC. The star symbol in FIGS. 4A and 4B indicates an error.

The RVLC is a variable-length code that can be decoded in both the forward and reverse directions. By using this code, "two-way decode" can be realized. As shown in FIG. 4A, in the case of a normal variable-length code, if the presence of an error is confirmed, the decoding process is temporarily stopped there, so that data following the error is lost.
On the other hand, as shown in FIG.
Then, if an error is found in the middle of decoding, the decoding process is temporarily stopped there and the next synchronization signal is detected.
When the next synchronization signal is detected, the bit string is decoded in the reverse direction. The start point of decoding is increased without new additional information, and the amount of information that can be decoded when an error occurs can be increased as compared with the conventional variable length code. The code increase of the RVLC is about 10% as compared with the code increase of a normal variable length code.

Next, Q in the CCS 10 of the present embodiment is
The oS mapping method will be described. Qo of CCS10
In the S control unit 60, the user request QoS is
As a QoS mapping method for converting to the QoS, a QoS mapping process using a spline function is performed. The QoS mapping process using the spline function is performed based on a plurality of sample data pairs (P _n , R _n ) (n = 1, 2,..., N) of a given user request QoS and resource QoS. A spline function S _m ″ (m = _m) that is an interpolation function for interpolating the relationship between the required QoS and the resource QoS.
1,2, ..., determines M), based on a user request QoS P _u which a user requests, resource QoS by performing interpolation processing using the spline function S _m "R
Determine the _u, is characterized in that control to communicate according to the resource QoS R _u determined above.

In the moving image communication system according to the present embodiment, first, the user looks at the moving image displayed on the mobile PC 32 and displays an application Q indicating the desired quality of the moving image.
Set the user request QoS P _u in oS, this setting value, together with the QoS change policy, is input to the QoS controller 60 of the CCS10. The QoS control unit 60
QoS mapping process using a spline function, with a spline function obtained based on the boundary conditions stored in the mapping table and the boundary condition memory 82 to be stored in the mapping table memory 81, the user request QoS P _u determining a resource QoS R _u based on, it calculates the optimal QoS based on R _u, the amount of resources specified by the calculated QoS using resource reservation protocol or the like to test whether available. If available, the QoS control unit 60 secures a necessary band or the like according to the calculated QoS and the monitoring result from the resource monitoring unit 61, and communicates with the mobile PC 32.

Next, a QoS mapping process using a spline function and three memories 81 and 8 used for the QoS mapping process
2 and 83 will be described. The mapping table memory 81 stores the application QoS requested by the user,
N sample data pairs リ ソ ー ス (P
₁ , R ₂ ), (P ₂ , R ₂ ),..., (P _n , R _n ),.
_N , R _N )} are stored in advance as a mapping table. The following table shows N sample data pairs (P _n , R _n ) (n =
1, 2,..., N).

[0031]

[Table 1] N sample data pairs (P _n , R _n ) previously stored in the mapping table memory 81 ─────────── (P ₁ , R ₁ ) = ({p ₁₁ , p ₂₁ ,..., P _k1 }, {r ₁₁ , r ₂₁ ,..., R _M1 }) (P ₂ , R ₂ ) = ({p ₁₂ , p ₂₂ ,..., P _k2 }, {r ₁₂ , r ₂₂ ,..., R _M2 }) (P ₃ , R ₃ ) = ({p ₁₃ , p ₂₃ ,. _{k3}, {r 13, r} 23, ..., r M3}) ............ (P n, R n) = ({p 1n, p 2n, ..., p kn}, {r 1n, r 2n, ... , R _Mn }) ... (P _N , _RN ) = ({p _1N , p _2N , ..., p _kN }, {r _1N , r _2N , ..., r _MN })} ─────────────────────────────

As shown in Table 1, N sample data pairs (P _n , R _n ) (n = 1, 2,..., N) are represented by K
Application with two elements QoS P _n = ｛p
_1n, p _2n, ..., a p _kn}, resource QoS R _n = {r _1n having M elements, r _2n, ..., a data pair made up from the r _Mn}. Specifically, in the present embodiment, the K elements of the application QoS P _n are the frame size, the frame rate, and the quantization coefficient (K = 3), and the M elements of the resource QoS R _n are:
Required bandwidth and CPU operation rate (M = 2). This sample data pair (P _n , R _n ) means that the resource QoS required for performing moving image communication when the application QoS is P _n is R _n .

First, in the mapping process using the spline function, N sample data pairs (P _n , P _n ,
R _n ) and the boundary condition of the spline function S _m stored in advance in the boundary condition memory 82, and
The spline coefficients of each of the spline functions S _m are calculated, and the spline coefficients are stored in the spline coefficient memory 83. The spline function for which the spline coefficients have been calculated is set as S _m ″ (m = 1, 2,..., M).

[0034] Here, each of the M is spline function S _m, corresponds to each element r _mn of M resource QoS R _n, when determining the elements r _mn of M resource QoS R _n And r _mn = S _m ″ (P _n ).
The spline function S _m is a cubic natural spline function. As a modification, a B-spline function may be used instead of the natural spline function.

[0035] Figure 7, in the mapping process using a spline function performed by the QoS controller 60 of FIG. 1, when using the spline function S _m ", from the user request QoS P _u resource QoS R _u elements is a graph showing mapping relationship to r _mu (the example of K = 1). Referring to FIG. 7, the value of the user requested QoS P _u, P _{u1,
P u 2, ..., P ux} , ..., when changing the P _uX, the value of the user request QoS P _u, using the spline function S _m "is an interpolation function which is previously determined, the resource QoS R _u the value of the element _{r mu r mu1, r mu2,} ..., r mux, ..., it can be seen that are determined respectively r _MUX.

Next, in the mapping process using the spline function, the user request QoS P _u
When given from the resource QoS R _u based on the user request QoS P _u using the spline function S _m "
Determining each element r _mu, its result resource QoS R _u
= {R _1u , r _2u ,..., R _Mu }.

The moving picture decoding section 51 decodes the moving picture data received from the video server 30 by the network transceiver 50 and transmits the decoded data to the moving picture re-encoding section 52. The decoded moving image data is re-encoded based on the user requested QoS, the resource QoS, and the error resilience control technology, and transmitted to the mobile PC 32 via the network transceiver 50.

FIGS. 5 and 6 show the QoS control unit 60 of FIG.
5 is a flowchart of a QoS control process executed by the CPU. In FIG. 5, first, in step S1, the mobile PC
It is determined whether or not the application QoS request and the QoS change policy have been received from the P.32, and the process of step S1 is repeated until the application QoS request and the QoS change policy are received. If YES in step S1, the process proceeds to step S2. In step S2, CCS10
It is determined whether or not the resource information in step S2 has been received, and the process of step S2 is repeated until the resource information is received.
If it is ES, the process proceeds to step S3. In step S3,
Based on current resource information (including network resources and terminal resources), it is determined whether error resilience control processing is necessary. In step S4, it is determined whether error resilience control processing is required. If YES, the process proceeds to step S5, and if NO, the process proceeds to step S6. In step S5, an error resilience control process is performed using the coding error resilience control technique in the communication channel and the coding error resilience control technique in the information source as described above, and the process proceeds to step S6. In step S6, after the error resilience control process, the resource QoS required for realizing the application QoS is calculated using the QoS mapping method, and the process proceeds to step S6 in FIG.
Go to 7.

Next, in step S7 of FIG. 6, it is determined whether or not the calculated resource QoS is feasible with the current monitored resource information. If YES, the process proceeds to step S8, and if NO, the process proceeds to step S9. In step S9, the application QoS is changed based on the QoS change policy, and the resource QoS required for realizing the application QoS is calculated using a resource QoS mapping method.
Go to 10. In step S10, it is determined whether the calculated resource QoS is feasible with the current monitored resource information. If YES, the process proceeds to step S8, and if NO, the process proceeds to step S11. Step S
In 8, the re-encoding parameter is calculated based on the calculated resource QoS, and the moving image data is re-encoded with the calculated re-encoding parameter and transmitted to the mobile PC 32,
It returns to step S2 of FIG. In step S11, an application QoS request and QoS
An S change policy change request message is transmitted, and the process returns to step S1 in FIG.

FIG. 8 is a flowchart showing a mapping process using a spline function, which is executed by the QoS control unit 60 of FIG. This mapping process is used in step S6 of FIG. 5 and step S9 of FIG. As described above, a mobile PC in a video communication system
When moving image data is communicated between the video server device 32 and the video server device 30, the user sets a desired application QoS in the mobile PC 32, but determines a resource QoS that can be realized by the user request QoS, and It is necessary to determine whether communication is possible using resource QoS, and if communication is possible, it is necessary to control communication according to resource QoS.

Referring to FIG. 8, first, at step S21
Then, N sample data pairs (P _n ,
R _n ) is read from the mapping table memory 81,
Reading the M boundary conditions of the spline function S _m from the boundary condition memory 82. Next, in step S22, N
Based on the sample data pairs (P _n , R _n ) and the boundary conditions, the spline coefficients of the M spline functions S _m given in advance for the M elements r _{mn of} the resource QoS R _n are The spline coefficients calculated are stored in the spline coefficient memory 83, and the spline function for which the spline coefficients have been calculated is set as S _m ″.

Next, in step S23, the mobile
User request QoSP from PC32_uWhether there is
Judge and user requested QoS P_uIf there is, step S2
4. If no, go to user request QoS P_uIs entered
Loop processing until In step S24,
In function S_mThe user request QoS P using_uFrom litho
Source QoS R_uElement r_muMap to resources
QoS R_u= ｛R_1u, R _2u, ..., r_Mu｝
It returns to step S23. Resource obtained as described above
QoS R_uQoS control unit 60 determines the optimal Q based on
oS is calculated, and the mobile PC 32 is calculated according to the QoS.
Communicates with the video server device 30.

[0043]

FIG. 9 is a block diagram of the QoS control unit 60 shown in FIG.
It is an example in which QoS was changed based on an S mapping process and a QoS change policy given by a user, and is a graph showing a relationship between a frame rate, a quantization coefficient, and a bandwidth when a frame size is 320 × 240. As shown in FIG. 9, the frame size 3
When 20 × 240, a frame rate of 5, and a quantization coefficient of 95 are given, a resource Qo is determined by QoS mapping.
The required band is determined as S at the point indicated by A in the figure.
However, when it is determined that the resource QoS of the point A cannot be realized in the currently monitored resource information, the user request is made according to the QoS change policy.
It is automatically changed by the control unit 60. When the QoS change policy is a quantization coefficient, the quantization coefficient is reduced from, for example, 95 to 85, and the user request is changed from A to B in the figure. Also, when the QoS change policy is the frame rate, the frame rate is reduced from 5 to 3, for example,
The user request is changed from A to C in the figure.

<First Embodiment> The CCS 10 performs error control by using the FEC of the coding rate 2/3,
It is set that the information that the communication band of 56 kb / s is available is obtained. When the motion JPEG encoding method is used as the re-encoding method under these conditions, the frame size is 320 × 240 and the frame rate is 5 frame.
It is possible to transmit a moving image having es / s and a quantization coefficient of 90 to the mobile PC 32 as a receiver. Here, it was observed that the error rate of the communication channel was further increased by resource monitoring. The QoS control unit 60 that performs error control of the CCS 10 sets the FEC coding rate to １ ／.
If the RVLC is used to enhance error resilience, the available band is finally increased to about 174 since the code increase by the RVLC is about 10% higher than that of the normal coding method.
kb / s. Q of the QoS control unit 60
The re-encoding parameter is determined by the oS determination process based on the calculated available bandwidth and the QoS change policy from the mobile PC 32. For example, if the QoS change policy is a quantization coefficient, the frame size is 320 × 24
Assuming that the frame rate is 0, the frame rate is 5 frames / s, and the quantization coefficient is 80, recoding parameters are determined. On the other hand, if the QoS change policy is the frame rate,
Frame size 320x240, frame rate 3
Assuming that frames / s and the quantization coefficient are 90, re-encoding parameters are determined.

<Second Embodiment> It is assumed that the CCS 10 and the mobile PC 32 as a receiver each have a reference memory (not shown) of 2 Mbits. As H. Moving image transmission was performed in the NEWPRED ACK mode using the H.263 coding method, and information indicating that the round-trip transmission delay between the CCS 10 and the mobile PC 32 was two frames was obtained based on the result of monitoring by the resource monitoring unit 61. Under this condition, four frames of a moving image having a frame size of 320 × 240 can be stored in the reference memory.
Normal error control can be performed by the WPRED ACK mode. Here, it was observed that the round-trip transmission delay was increased to three frames by the resource monitoring unit 61. CC
If the NEWPRED ACK mode is subsequently used by the error control processing of the QoS control unit 60 in S10, the number of frames stored in the reference memory must be increased to 5 or more. By the QoS determination processing of the QoS control unit 60, it is calculated that five frames can be stored in the reference memory if the frame size is changed to 300 × 225, and that is determined as a re-encoding parameter. By this encoding conversion, the normal operation of the NEWPRED ACK mode is continuously guaranteed.

As described above, according to the present embodiment, in a heterogeneous communication environment in which wireless communication and wired communication coexist, error tolerance is adjusted in accordance with communication environment characteristics such as a dynamically changing communication band and a transmission error rate. Using technology and QoS conversion in conjunction, adaptively adjusting the quality of the video based on the QoS conversion policy specified by the user to provide video quality that meets the user's required policy according to the communication environment can do. That is, to dynamically and adaptively control the application QoS so as to eliminate communication errors in response to fluctuations in the communication environment and the terminal environment, and to provide a communication service with the application QoS conforming to the specification value requested by the user. Thus, the communication service can be provided while being significantly improved as compared with the conventional example.

[0047]

As described above, according to the communication service quality control method or control apparatus according to the present invention, the communication control means for controlling the quality of the communication service between a plurality of terminal devices connected via a network is provided. In a communication service quality control method or control apparatus for a terminal device provided with the terminal device, resource information of a terminal device realizing a communication service and resource information of a network are detected and output, and the service quality of a communication service application from one terminal device is determined. Upon receiving the request signal to be changed, after performing a predetermined error resilience control process based on the detected resource information, using a mapping method for converting the service quality of the application to the service quality of the resource, the request signal Resources required to perform the indicated quality of service of the application. Calculating the service quality, calculating the re-encoding parameter of the received data based on the calculated service quality of the resource, re-encoding the received data with the calculated re-encoding parameter and transmitting the request signal. Adaptively control the service quality of the application by transmitting to the terminal device, based on the service quality of the application of the change request from the terminal device that transmitted the request signal, based on the mapping method, using the mapping method, indicated by the change request Calculate the quality of service of the resources required to perform the quality of service of the application to be performed, calculate the re-coding parameters of the received data based on the calculated quality of service of the resources, and calculate the re-coding parameters with the calculated re-coding parameters. Re-encoding the received data and transmitting it to the terminal device that transmitted the request signal Ri adaptively control the service quality of the application. Therefore, according to the present invention, the application QoS is dynamically and adaptively controlled so as to eliminate communication errors in response to changes in the communication environment and the terminal environment, and the application QoS conforms to the specification value required by the user. The communication service can be provided, and the communication service can be provided while being significantly improved as compared with the conventional example.

[0048]

[0049]

[0050]

[0051]

[0052]

[Brief description of the drawings]

FIG. 1 shows a CCS 10 according to an embodiment of the present invention.
1 is a block diagram showing a moving image communication system on a network having a wireless communication network and a wired communication network provided with.

FIG. 2 is a diagram showing each function of a CCS 10 in FIG.

FIG. 3 is a block diagram showing a configuration of a CCS 10 in FIG.

4A and 4B are diagrams illustrating a normal variable length code and a reversible variable length code (RVLC), FIG. 4A is a diagram illustrating a normal variable length code, and FIG. 4B is a diagram illustrating an RVLC;

FIG. 5 is a flowchart illustrating a first part of a QoS control process performed by the QoS control unit 60 of FIG. 3;

FIG. 6 is a flowchart illustrating a second part of the QoS control process performed by the QoS control unit 60 of FIG. 3;

FIG. 7 is a diagram illustrating a user-requested QoS when a spline function S _m ″ is used in a mapping process using a spline function executed by the QoS control unit 60 in FIG. 1;
(Example K = 1) mapping relationship from P _u to element r _mu resource QoS R _u is a graph showing a.

8 is a flowchart illustrating a mapping process using a spline function, which is executed by the QoS control unit 60 of FIG.

9 is a graph showing an example in which QoS is changed by a mapping process by the QoS control unit 60 in FIG. 3, and showing a relationship between a frame rate, a quantization coefficient, and a bandwidth when a frame size is 320 × 240.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Communication coordination server (CCS), 11 ... Personal computer (PC), 12 ... Work station (WS), 20 ... Network (NE), 30 ... Video server device, 31 ... Wireless base station device, 32 ... Mobile personal computer (Mobile P
C), 50: Network transceiver, 51: Video decoding unit, 52: Video encoding unit, 60: QoS control unit, 61: Resource monitoring unit, 70: CPU, 81: Mapping table memory, 82: Boundary condition Memory 83, spline coefficient memory,

────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Jun Matsuda 5th Sanraya, Daiya, Seika-cho, Soraku-gun, Kyoto Pref. 149009 (JP, A) IEICE Technical Report CQ 97-66, “A Consideration of Framework for Adaptive Information and Communications Applications-Agent-Based System Architecture” (1997-12-19) p. 53-60 Proceedings of the 1998 IEICE Communication Society Conference, Vol. 2, B-11-10, “Communication coordination server for adaptive information communication applications” (1998-9-7), p. 512 IPSJ 57th Annual Conference Proceedings CD-ROM, IF-03 "QoS management method for adaptive information and communication applications" (1998-10-5) Proceedings of the 1998 IEICE General Conference , Communication 2, SB-11-2 “QoS mapping using spline function” (1998-3-27) p. 728-729 1999 IEICE General Conference, Communication 2, B-11-15, “QoS adjustment method considering error resilience in multimedia mobile communication applications” (1999-3-25), p. . 548 1999 IEICE Communication General Conference, Proceedings, Communication 2, B-11-16 “Dynamic QoS Mapping by Spline Neural Network” (1999-3-25) p. 549 1999 IEICE Communication General Conference, Proceedings, Communication 2, B-11-17 “Adaptive QoS Adjustment Method Using Multi-agents” (1999-3-25) p. 550 1999 IEICE General Conference, Communication 2, B-11-18, “Adaptive end-to-end QoS control model using multiagents” (1999-3-25), p. 551 Technical Report of the Institute of Electronics, Information and Communication Engineers, CQ 97-6, "End-user Networking-QoS Control by User Adaptive Agent-" (1997-5-28), p. 39-46 Proc. Of the 59th Annual Conference of IPSJ CD-ROM, 2V-01 “Acquisition of QoS mapping rules in video transmission” (1999-9-29) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04L 12/28 H04L 12 / 56 H04L 1/00

Claims (4)

(57) [Claims] 1. A method for controlling the quality of a communication service between a plurality of terminal devices connected via a network, the control method comprising: Detecting and outputting information and network resource information; and receiving a request signal for changing the service quality of a communication service application from one terminal device, performing predetermined error resilience control based on the detected resource information. After performing the processing, the service quality of the resource required to execute the service quality of the application indicated by the request signal is calculated using a mapping method for converting the service quality of the application to the service quality of the resource, and the calculation is performed. Data received based on the quality of service of the Calculating the encoding parameters, adaptively controlling the service quality of the application by re-encoding the data received with the calculated re-encoding parameters and transmitting the request signal to the terminal device that transmitted the request signal, Based on the service quality of the application of the change request from the terminal device that transmitted the request signal, using the above mapping method, calculate the service quality of the resources required to execute the service quality of the application indicated by the change request. Calculating the re-encoding parameter of the received data based on the calculated quality of service of the resource, re-encoding the received data with the calculated re-encoding parameter, and transmitting the re-encoded parameter to the terminal device that transmitted the request signal. Including adaptively controlling the quality of service of the application by Communication service quality control method for. 2. The method according to claim 1, wherein the error resilience control process is performed using a combination of a coding error resilience control method in a communication channel and a coding error resilience control method in an information source. Communication service quality control method. 3. A communication service quality control device for a terminal device having communication control means for controlling the quality of communication service between a plurality of terminal devices connected via a network, wherein the resource of the terminal device realizing the communication service is provided. Detecting means for detecting and outputting information and network resource information, wherein the communication control means detects, when receiving a request signal for changing the service quality of an application of a communication service from one terminal device, the detected resource information. After performing a predetermined error resilience control process based on the resource quality required for executing the service quality of the application indicated by the request signal, using a mapping method for converting the service quality of the application to the service quality of the resource Service quality of the calculated resources and service goods of the calculated resources Calculate the re-encoding parameter of the received data based on the, re-encode the received data with the calculated re-encoding parameter and send it to the terminal device that sent the request signal to adapt the service quality of the application The communication control means executes the service quality of the application indicated by the change request using the mapping method, based on the service quality of the application of the change request from the terminal device that transmitted the request signal. Calculate the quality of service of the resources needed to calculate the re-encoding parameters of the received data based on the calculated quality of service of the resources, and re-encode the received data with the calculated re-encoding parameters Service to the terminal device that sent the request signal Communication service quality control system, characterized by adaptively controlled. 4. The method according to claim 3, wherein the error resilience control processing is performed using a combination of a coding error resilience control method in a communication channel and a coding error resilience control method in an information source. Communication service quality control device.