KR100548324B1 - Video data transmission bit rate control method for mobile communication system - Google Patents

Abstract

The present invention relates to a method of controlling a transmission bit rate of a mobile communication system, and the base station predicts a cell loss rate and feeds back quantization level change information to a terminal, thereby reducing cell loss or delay. To this end, the present invention comprises the steps of setting the MPEG data transmission bit rate between the base station and the terminal, and transmitting the MPEG data at the set transmission bit rate in each terminal; Classifying MPEG traffic transmitted from each terminal by frame type, and extracting each frame bit amount for each of the divided frame types; Applying the extracted frame bit amount to an AR (Autogressive) model to predict the multiplexed traffic distribution and calculating a transmission bit amount of MPEG data based on the prediction result; Comparing the calculated transmission bit amount with a service capacity; If the amount of transmission bits exceeds the service capacity, reducing the transmission bit rate by lowering the quantization level of each terminal; Each of the terminals transmits MPEG data to the base station at a reduced transmission bit rate.

Description

VIDEO DATA TRANSMISSION BIT RATE CONTROL METHOD FOR MOBILE COMMUNICATION SYSTEM}

1 is a flowchart illustrating a method for controlling video data transmission bit rate in a mobile communication system according to the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of controlling bit rate of image data transmission in a mobile communication system. In particular, a base station predicts a cell loss rate and feeds back quantization level change information to a terminal, thereby reducing cell loss or delay. The present invention relates to a bit rate control method.

In a general method of controlling a transmission bit rate of a mobile communication system, a bit rate is adjusted according to a usage parameter control (UPC), which is a traffic descriptor negotiated in advance, between a terminal and a network without considering the state of the network.

However, the method of controlling the transmission bit rate of such a mobile communication system is difficult to consider the state of the network such as congestion that causes cell loss or delay in the network. There is a problem in that multiplexing gain that occurs during connection cannot be obtained.

The present invention has been made to solve the above problems, the base station predicts the cell loss rate by feeding back the quantization level change information to the terminal, the transmission bit rate control method of the mobile communication system to reduce the cell loss or delay The purpose is to provide.

The present invention for achieving the above object, to set the MPEG (MPEG) data transmission bit rate between the base station and the terminal,
Transmitting MPEG data at each of the terminals at the set transmission bit rate;
Classifying MPEG traffic transmitted from each terminal by frame type, and extracting each frame bit amount for each of the divided frame types;
Applying the extracted frame bit amount to an AR (Autogressive) model to predict the multiplexed traffic distribution and calculating a transmission bit amount of MPEG data based on the prediction result;
Comparing the calculated transmission bit amount with a service capacity;
If the amount of transmission bits exceeds the service capacity, reducing the transmission bit rate by lowering the quantization level of each terminal;
Each of the terminals transmits MPEG data to the base station at the reduced transmission bit rate.
Hereinafter, with reference to the accompanying drawings, the operation and effects of the video data transmission bit rate control method of the mobile communication system according to the present invention will be described in detail.

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First, MPEG is composed of three types of frames, each of which has a different compression efficiency. The amount of data generated in each frame is severely changed, and the type of traffic is determined according to the period and frequency of the I.P.B frame type.

In this case, a structure in which successive frames are divided into I-frames is called a GOP (Group of Picture) structure, which is represented through two parameters (N, M).

Here, N is a repetition period of the I frame, M is a period in which the P frame is repeated.

For example, a frame pattern of an MPEG having a GOP parameter of (N = 12, M = 3) has a form of 'IBBPBBP BBP ...', and generally indicates a correlation with previous data. Use autocorrelation function to

However, since the frame pattern of the entire traffic is repeated in the GOP structure, the correlation with the previous frame has a complicated form, so it is difficult to approximate the autocorrelation function of the total traffic to the linear model.

In this case, the data divided by each IPB frame type is similar to the statistical characteristics of general video traffic, and has a linear relationship with the previous data, so that the autocorrelation function of each type of data can be approximated with an exponential function. Star data can be modeled as an AR (Autogressive) model in which the autocorrelation function takes the form of an exponential function.

The primary process of the AR (Autogressive) model is expressed by the following equation.

[Equation]

Where a and b are constants, n is the frame number, X (n) is the traffic volume of the nth frame,

That is, in order to predict the distribution of the frame bit amount, the present invention classifies MPEG traffic transmitted from each terminal by each frame type and then applies each frame bit amount to an AR (Autogressive) model. It is.

1 is a flowchart illustrating a method of controlling a video data transmission bit rate of a mobile communication system according to the present invention. As shown in FIG. 1, an MPEG data transmission bit rate is set between a base station and a terminal, and the MPEG bit is used as the transmission bit rate. Transmitting data (SP1, SP2); Classifying the MPEG traffic by frame type (SP3); Predicting the multiplexed traffic distribution by applying the frame bit amount to the AR model (SP4, SP5); Calculating a transmission bit amount of MPEG data and comparing the transmission bit amount with a service capacity (SP6, SP7); As a result of the comparison, if the bit amount exceeds the service capacity, the quantization level is lowered to reduce the transmission bit rate, and then MPEG data is transmitted at the reduced transmission bit rate (SP8, SP9). The operation of the will be described.

First, the MPEG data transmission bit rate between the base station and the terminal is set, and then MPEG data is transmitted at the set transmission bit rate (SP1, SP2).

Next, the base station divides the MPEG traffic transmitted from the terminal by frame type (SP3).

For example, since the MPEG traffic is modeled by frame type, the base station actually performs parameters a_I, b_I, eta (average value) _I for I frames transmitted from each terminal, parameters a_P for P frames, b_P, eta_P, and parameters a_B, b_B, and eta_B for B frames, that is, the base station stores the amount of data (D_I ^ i, D_P) for each frame type of MPEG (MPEG) traffic transmitted by each UE in each video frame period. ^ i and D_B ^ i) are stored in a memory (not shown) in the controller (not shown).

Here, D_I ^ i represents the bit amount of the I frame sent by T_i.

In this case, the stored data amount for each frame type is updated and stored with the new incoming data amount of the same type every frame.

Next, the bit amount for each frame type is applied to an AR (Autogressive) model to predict the multiplexed traffic distribution (SP4, SP5).

That is, the control unit of the base station is transmitted from all the terminals connected to the base station, obtains the multiplexed probability distribution by using the predictive traffic model and the AR (Autogressive) parameter value and data amount stored in the memory of the base station, and then the multiplexed probability distribution Predict the bit quantity distribution to be input to the base station in the next frame.

Next, the transmission bit amount of MPEG data is calculated based on the predicted bit amount distribution (SP6).
Then, the calculated transmission bit amount is compared with the service capacity (SP7). If the MPEG data transmission bit amount exceeds the service capacity based on the comparison result, the quantization level is lowered to reduce the transmission bit rate.
Accordingly, the respective terminals transmit MPEG data at the reduced transmission bit rate (SP8, SP9).

If the transmission bit amount of the MPEG data does not exceed the service capacity, the MPEG data is transmitted at a predetermined transmission bit rate (SP10).

That is, the base station transmits the quantization level increase and decrease information resulting from the bit rate control to all the terminals connected to the base station, and all the terminals receiving the increase and decrease information of the quantization level are quantized received from the base station at the previously negotiated quantization level. The image data is coded at a new quantization level obtained by subtracting the level increase / decrease information, and then transmitted to the base station.

The specific embodiments or examples made in the detailed description of the present invention are intended to clarify the technical contents of the present invention to the extent that they should not be construed as limited to these specific embodiments and should not be construed in consultation. Various changes can be made within the scope of.

As described in detail above, the present invention compares the predicted cell generation amount with the service capacity that the base station can accommodate and performs quantization adjustment, thereby reducing the load on the terminal and efficiently managing the entire network in the base station. There is.

Claims (4)

Sets the MPEG data transmission bit rate between the base station and the terminals, Transmitting MPEG data at each of the terminals at the set transmission bit rate; Classifying MPEG traffic transmitted from each terminal by frame type, and extracting each frame bit amount for each of the divided frame types; Applying the extracted frame bit amount to an AR (Autogressive) model to predict the multiplexed traffic distribution and calculating a transmission bit amount of MPEG data based on the prediction result; Comparing the calculated transmission bit amount with a service capacity; If the amount of transmission bits exceeds the service capacity, reducing the transmission bit rate by lowering the quantization level of each terminal; And transmitting, by the respective terminals, MPEG data to the base station at a reduced transmission bit rate, respectively. The method of claim 1, wherein the classifying MPEG traffic by frame type comprises: Storing an AR (Autogressive) parameter transmitted from the terminal in a memory of the base station; And storing the amount of data for each frame type of MPEG traffic transmitted from the terminal for each video frame period. The method of claim 2, wherein the storing of the data amount for each frame type comprises: A method of controlling a video data transmission bit rate of a mobile communication system, characterized in that the data amount of each frame type is updated and stored every frame with the same amount of data. The method of claim 1, wherein predicting the multiplexed traffic distribution comprises: A method of controlling the video data transmission bit rate of a mobile communication system, by applying an AR (Autogressive) parameter value and a data amount to a predictive traffic model, and estimating a distribution of bit amounts to be input to a base station in a next frame.

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