JP4011518B2 - Mobile communication terminal and distribution device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a distribution device (hereinafter referred to as a server) that distributes wireless packet data, and a mobile communication terminal (hereinafter referred to as a portable terminal) that receives wireless packet data from the server. The present invention relates to a server that performs streaming distribution of data and a mobile terminal that receives moving image data streamed from this server in real time and reproduces a desired moving image.
[0002]
[Prior art]
2. Description of the Related Art In recent years, mobile terminals such as mobile phones that can capture moving image data streamed from a server and reproduce a desired moving image in real time have been widely used. By streaming video data from the server to the mobile terminal, the mobile terminal plays the moving image in real time while sequentially downloading the video data that is transmitted one after another. However, it does not require a large memory capacity. Therefore, even with an inexpensive portable terminal having a small memory capacity, advanced moving image data can be easily reproduced and enjoyed as a moving image. The following Patent Document 1 reports a technique for streaming distribution of moving image data.
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 2003-78954
[Problems to be solved by the invention]
However, in the above-described conventional techniques including Patent Document 1, when moving image data is streamed from the server to the mobile terminal, the moving image data may not be distributed in real time when the communication state is congested. Alternatively, even if the video data is distributed to the mobile terminal in real time, some video data is lost because of insufficient communication line capacity, and as a result, a moving image with good image quality is obtained. Sometimes not. On the other hand, when a shortage occurs in the communication line capacity, the receiving side (that is, the mobile terminal side) estimates the circuit state with high accuracy using not only the pilot signal of the own channel but also the pilot signal of the other channel, A technique for improving reception characteristics by selecting an optimum channel is known. However, this technique is intended to improve reception characteristics by performing circuit estimation with high accuracy in a CDMA (Code Division Multiple Access) system wireless communication apparatus. In streaming delivery, reception characteristics cannot be improved when communication conditions deteriorate.
[0005]
The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a distribution device capable of streaming video data in an optimum state regardless of the communication status, and a streaming distribution. Another object of the present invention is to provide a mobile communication terminal (that is, a portable terminal) that can download the moving image data in an optimal state in real time.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, a mobile communication terminal according to the present invention is a mobile communication terminal that receives moving image data streamed from a distribution device that provides information and reproduces the moving image data. Receiving means for receiving using a communication channel, real-time requesting means for requesting real-time performance for moving image data streamed from a distribution device, and receiving state at specified time intervals during streaming distribution of moving image data And a switching means for receiving the moving image data by switching to a communication channel different from the communication channel when the reception state deteriorates with respect to streaming delivery that requires real-time performance. And
[0007]
That is, according to the mobile communication terminal of the present invention, when real-time performance is required for moving image data received by a mobile communication terminal (that is, DO terminal) applied to CDMA2000 1XEV-DO, a conventional traffic channel is used. In addition, other communication channels are allocated so that the communication quality can be guaranteed. As a result, when the communication state by the traffic channel deteriorates, the moving image data is streamed and switched to the assigned communication channel immediately. Therefore, the mobile communication terminal can always reproduce a high-quality moving image regardless of the communication state. Further, according to the mobile communication terminal of the present invention, it is necessary only when the user himself / herself needs real-time property when reproducing moving image data, and when real-time property is necessary when reproducing moving image data. Other communication channels may be used depending on the situation. If the real-time property is not required, the moving image data can be reproduced with the normal traffic channel without switching the channel. As described above, since the mobile terminal can be used in accordance with the user's preference, the usability on the user side is further improved.
[0008]
The distribution device of the present invention is a distribution device for streaming distribution of moving image data to a mobile communication terminal, and a distribution request signal for requesting streaming distribution of moving image data and moving image data to be distributed for streaming from the mobile communication terminal. A receiving means for receiving a real-time request signal for requesting real-time characteristics, and an assigning means for allocating a communication channel for streaming distribution of the requested video data, wherein the receiving means receives the real-time request signal The assigning means assigns a communication channel different from the communication channel.
[0009]
That is, the distribution device of the present invention performs streaming distribution of moving image data through a normal traffic channel or another communication channel based on real-time request information from the mobile communication terminal and reception state change information. Is determined. That is, moving image data is distributed in a communication mode desired by the user according to the usage state of the mobile communication terminal on the user side. As a result, the user can always reproduce the moving image in a satisfactory state.
[0010]
In addition to the above-described invention, the distribution apparatus of the present invention further includes a detection unit that detects the communication quality of the communication channel, and a switching unit that switches to the different communication channel when the communication quality of the communication channel in communication deteriorates. It is characterized by comprising. That is, according to the distribution device of the present invention, it is possible to always distribute the optimum moving image data to the mobile communication terminal while monitoring the communication channel traffic.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
First, a description will be given of the realization of a service-compatible terminal for the mobile terminal to perform streaming of moving image data without failure in the mobile communication system and the current state of service quality assurance in the system. As a standard of the third generation mobile communication system “ITM-2000” having high-speed data transmission capability, CDMA (Code Division Multiple Access), which is a method proposed by the United States to ITU (International Telecommunication Union) Multiple access) 2000. In the CDMA2000, a system to which a 1.25 MHz spread bandwidth dedicated for data communication used as a wireless standard is assigned is “1x”. 1XEV-DO (1x Evolution Data Only) is a high-speed data communication standard for mobile terminals based on HDR (High Data Rate) based on "1x". In addition, the standard of 1XEV-DO (hereinafter referred to as DO) is a C.C. developed by 3GPP2 (Third Generation Partnership Project), a group that creates specifications for next-generation mobile communication systems. S0024. Ver. It is 3.0, and this standard is the minimum requirement for constructing a DO system.
[0012]
Therefore, the know-how for maintaining QoS (Quality of Service) in the operation of a mobile terminal that actually uses the DO system (hereinafter referred to as a DO terminal if necessary) is a communication system of the mobile terminal. This means how well the technical cooperation between the carrier operator operating the mobile phone and the set maker that manufactures the mobile terminal is performed. As is well known, the DO system is a system specialized in data communication for connecting to the Internet with a mobile terminal, and is characterized by a downlink (communication line link from the base station side to the mobile terminal). Assumes a certain usage.
[0013]
Also, in the DO system usage environment, phenomena such as a fading phenomenon in which received power fluctuates due to movement of a mobile terminal, which is a phenomenon peculiar to mobile terminals, and a phenomenon such as radio interference interference peculiar to CDMA cannot be avoided. Therefore, the DO system uplinks the reception state (mainly, the value of C / I: Carrier [carrier] / Interference [interference] or DRC (Data Rate Control Bit) derived from C / I)) ( Report to the base station side via the communication link from the mobile terminal to the base station side). As a result, channel scheduling peculiar to the DO system allows the mobile terminal class to be differentiated according to the transmission rate in the determination result of the reception status, and the reception level is low, “LOW”, and at a medium level. There are three stages: “MID” and “HIGH” with a high level.
[0014]
When the reception state is “LOW”, the error tolerance is high (large), but is assigned by a modulation method called QPSK (Quadrature Phase Shift Keying), which is a four-phase modulation method with a large overhead. Also, when the reception state is “MID”, it is a modulation method called 8PSK (8 Phase Shift Keying), which is an 8-phase modulation method that has normal error tolerance, is not so much overhead, and has a higher transmission efficiency than QPSK. Assigned. Furthermore, when the reception state is “HIGH”, error tolerance is low (small), but 4 bits (16 values) of information can be transmitted in one symbol, and data with a large amount of information can be transmitted at high speed by a narrow band. It is assigned by a modulation scheme called 16QAM (16 Quadrature Amplitude Modulation) which is a value transmission modulation scheme.
[0015]
FIG. 4 is a diagram illustrating the relationship between the used slot length, the modulation scheme to be implemented, and error tolerance for each transfer rate. As shown in FIG. 4, a QPSK modulation scheme with high (high) error tolerance is assigned when the transfer rate is low, and an 8PSK modulation scheme is assigned with medium error tolerance when the transfer rate is medium. Furthermore, 16QAM, which is a modulation scheme with low (small) error tolerance, is assigned for a high transfer rate. Therefore, by maximizing the processing capacity (throughput) of the hard disk sector by minimizing the channel occupancy time, that is, by not retransmitting or waiting for data during streaming delivery It aims to improve the usage efficiency on the system side.
[0016]
As a result, an application on the mobile terminal side, which is a mobile terminal, is able to optimally capture MPEG (Motion Picture Experts Group) compressed digital images and reproduce a good moving image. As described above, improvement of video streaming applications is greatly related to product differentiation of mobile terminals, so that carrier operators involved in video streaming distribution are also striving to improve their services. In addition, in order to actually succeed in the commercial service of moving image content, it depends on how to eliminate the trouble at the time of moving image reproduction in the mobile communication terminal.
[0017]
FIG. 3 is a flowchart showing the flow of processing performed when a DO terminal is activated or when a DO system is used. As shown in FIG. 3, first, it is determined whether or not the user activates the DO terminal or uses the DO system (step S21), and it is determined that the DO terminal is activated or the DO system is used. Then (Yes in step S21), a “data communication request” is immediately issued to the communication network of the DO system (step S22). In this way, when the DO terminal is determined to be activated or used when the DO terminal is activated or used, the DO function sequence is started simply by issuing a “data communication request” to the communication network of the DO system. At this time, the DO terminal is scheduled only by an instruction from the base station side (system side).
[0018]
However, the essential items for streaming video distribution to mobile terminals (that is, DO terminals) are the same as in the case of moving image browsing using a fixed network and a personal computer (PC) that are generally performed. There is no outage or disruption, and there is real-time data distribution. In addition, even when a DO terminal captures a still image or a moving image by WEB browsing for browsing various home pages while following links using a WEB browser, MPEG4 repairs some data errors. However, the repair function is suddenly deteriorated near the boundary of a data error of a certain level or more, and a remarkable instability phenomenon peculiar to quantization such as block noise occurs.
[0019]
In addition, as a trend of users, it is expected that moving images that can be seen at home can be seen on mobile phones and mobile terminals. Therefore, when viewing a moving image on a DO terminal, it depends on how the streaming distribution is performed without stopping, disturbing, or dropping frames. For these reasons, it is desired to develop an application that can adapt to the motion picture in the DO system. Therefore, video streaming in a mobile environment where communication is interrupted on the way, such as with current mobile terminals, stabilizes video data with only one communication channel that is unilaterally allocated by the channel scheduler of the DO terminal. It is impossible to distribute it automatically.
[0020]
Further, in order to realize a mobile terminal that can never be cut off, the communication area may be limited. However, if such an area limitation is performed, the advantage of the mobile terminal as a mobile object is impaired. Therefore, how to realize stable video streaming delivery is desired in a mobile environment where communication is always cut off during use as in the present situation. Furthermore, on the infrastructure side and the DO terminal side, it is essential to realize stable video streaming delivery without significant addition or change of hardware and software.
[0021]
Therefore, in the present invention, in addition to a normal traffic channel, a communication line between a server that distributes moving image data by streaming and a mobile terminal that receives and reproduces moving image data distributed from the server in real time is separately provided. Pre-assign channels. Then, when the communication status in the currently used traffic channel is bad, the channel is immediately switched to another channel. As a result, the moving image data distributed in a streaming manner can always ensure a stable real-time property regardless of the communication state. More specifically, when requesting distribution of content requiring real-time property from the mobile terminal to the distribution device, another channel is assigned by setting a 1-bit flag indicating the request for real-time property. .
[0022]
Hereinafter, an embodiment of the present invention in which a distribution device (such as a server or a base station) performs streaming distribution of moving image data to a mobile terminal (that is, a mobile communication terminal) will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a server for streaming distribution of moving image data and a mobile terminal that receives and reproduces moving image data distributed from the server in the present invention. Therefore, with reference to FIG. 1, a description will be given of the realization of a portable terminal (that is, a DO terminal) compatible with DO service for performing streaming distribution of moving image data without failure in the DO system, and QoS guarantee in the DO system. .
[0023]
In FIG. 1, a DO system that performs streaming distribution of moving image data includes a distribution device 1 that distributes moving image data in a streaming manner, and a portable terminal that receives moving image data streamed from the distribution device 1 in real time and reproduces a moving image. (Mobile communication terminal) 2. The downlink communication channel between the distribution device 1 and the mobile terminal 2 includes a traffic channel that performs streaming distribution of moving image data in a normal use state, and QoS (service quality) when the communication state in the traffic channel deteriorates. ) And the second and third candidate channels for performing streaming distribution of moving image data.
[0024]
The mobile terminal 2 receives a moving image streaming request unit 21 that requests the distribution device 1 for streaming distribution of moving image data, a real-time property request unit 22 that requests real-time property of the moving image data streamed from the distribution device 1, and a reception Display unit 23 that displays a moving image obtained by reproducing the moving image data in real time, and a reception state check unit that checks a reception state at a predetermined time interval during streaming distribution of the moving image data and notifies the distribution device 1 of the reception state 24.
[0025]
In addition, the distribution device 1 guarantees QoS (service quality) when a traffic channel communication state deteriorates, and a traffic channel assignment unit 11 that assigns a traffic channel as a communication channel for streaming streaming of moving image data in a normal state. The channel allocation unit 12 that allocates the second and third candidate channels for performing streaming distribution of moving image data and the real-time request for streaming distribution from the mobile terminal 2 are confirmed, and the channel allocation unit 12 determines the candidate channel. The real-time request confirmation unit 13 that notifies the allocation to stand by and the streaming distribution of the video data to the channel allocation unit 12 from the traffic channel to the candidate channel according to the reception state of the video data received by the mobile terminal 2 Whether to switch To determine, it has a configuration that includes a terminal reception state determination unit 14 for instructing whether to switch. That is, when the terminal reception state determination unit 14 detects that the reception state of the mobile terminal 2 through the traffic channel has changed downward, the terminal reception state determination unit 14 switches to the candidate channel, and when the change in the reception state of the moving image data is not recognized or the degree of change When it is small, an instruction is given to maintain the current traffic channel.
[0026]
Next, a streaming distribution operation of moving image data performed between the distribution device 1 and the portable terminal 2 in the DO system shown in FIG. 1 will be described. First, when a user requests streaming distribution of moving image data to the distribution apparatus 1 by the moving image streaming request unit 21 of the mobile terminal 2, the distribution apparatus 1 allocates a traffic channel by the traffic channel allocation unit 11, and passes through this traffic channel. The moving image data is streamed to the portable terminal 2. Next, when the user requests the real-time property of the moving image streaming distribution by the real-time property requesting unit 22 while confirming the moving image displayed in real time on the display unit 23 of the mobile terminal 2, the user requests the distribution device 1 to perform “moving image streaming”. Real-time request ”is notified. Then, the real-time request confirmation unit 13 of the distribution apparatus 1 confirms the “real-time streaming request for video streaming” from the mobile terminal 2 and notifies the channel allocation unit 12 to stand by for candidate channel allocation.
[0027]
On the other hand, the reception state check unit 24 of the mobile terminal 2 checks the reception state at a predetermined time interval and notifies the distribution device 1 during streaming distribution of moving image data. Then, when the terminal reception state determination unit 14 of the distribution device 1 detects that the reception state of the moving image data received by the mobile terminal 2 has changed in the deterioration direction, if the degree of change is large, the channel allocation The unit 12 is instructed to synchronously switch the streaming distribution of the moving image data from the traffic channel to the candidate channel. On the other hand, if the change in the reception state of the received moving image data cannot be detected or the degree of the change is small, the candidate channel remains in the standby state and the communication candidates on the current traffic channel are maintained.
[0028]
Next, the moving image data streaming distribution operation performed between the distribution apparatus 1 and the portable terminal 2 will be described in more detail using a flowchart. FIG. 2 is a flowchart showing a flow of streaming distribution of moving image data performed between the server and the DO terminal in the present invention. In the flowchart of FIG. 2, the process flow up to step S4 is the DO terminal process, and the process after step S5 is the process flow of the distribution apparatus.
[0029]
First, it is determined whether or not to perform video streaming on the DO terminal which is a portable terminal (step S1), and when the video streaming is performed on the DO terminal (Yes in step S1), a real-time property is required ( In the case of Yes in step S2, a flag indicating “real-time maintenance request” is set to “1” (step S3), and a “data communication request” is issued (step S4). Next, when the distribution apparatus receives a “data communication request” from the DO terminal through the DO communication network, the distribution apparatus determines whether or not the “real time maintenance request” flag is “1” (step S5). If it is determined that the “real-time maintenance request” flag from the terminal is “1” (Yes in step S5), the second or third candidate channel set in advance is assigned (step S6).
[0030]
The distribution apparatus 1 monitors the reception state of the DO terminal at a specified time interval (step S7), and determines whether or not the reception state of the DO terminal has deteriorated during that time (step S8). Here, when deterioration of the reception state of the DO terminal is recognized (YES in step S8), the DO terminal is changed to the second or third supplemental channel set in advance (step S9), and the DO terminal If the degradation of the reception state is not recognized or if the degradation of the reception state is extremely small (No in step S8), the communication using the current traffic channel is maintained (step S10).
[0031]
Then, it is determined whether or not the user has made a DO terminal termination request (step S11). If the DO terminal termination request has not been made (No in step S11), the process returns to step S7. The reception status of the DO terminal is continuously monitored in the same step. On the other hand, when the DO terminal makes an end request (Yes in step S11), the DO terminal returns to the standby state. In this way, when the distribution apparatus 1 monitors the reception state of the DO terminal at a specified time interval, when the deterioration of the reception state of the moving image data is recognized during that time, the communication is changed to the candidate channel communication, otherwise. In some cases, communication using the current traffic channel is maintained.
[0032]
The embodiment described above is an example for explaining the present invention, and the present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the gist of the invention. That is, in the above embodiment, the mobile terminal which is a mobile terminal of the DO system applied in 1XEV-DO of CDMA2000 has been described, but the same operation as in the above embodiment is possible even in other communication systems. Needless to say, the effects can be realized.
The distribution apparatus indicates a system-side apparatus, and includes a base station that performs wireless communication with a mobile communication terminal, a distribution server that stores moving image data, and the like. Note that another device is interposed between the base station and the distribution server and is connected by a communication line.
[0033]
【The invention's effect】
As described above, downlink QoS (service quality) is not guaranteed in the conventional wireless packet data communication system, so that moving image data that requires real-time transmission is stopped, disturbed, interrupted, etc. Has occurred, giving the user an uncomfortable feeling during playback of moving images. However, according to the present invention, in a downlink wireless packet data communication system that performs moving image transmission that requires real-time performance, the mobile communication terminal also requires real-time performance when requesting streaming delivery of moving image data. Is informed. That is, if it is expected that the communication quality will deteriorate and the real-time property of the traffic channel cannot be maintained, the cause channel scheduler assigns a specific channel and switches to the candidate channel before the traffic channel is disconnected. Real-time performance is ensured. Thus, the user can always play back a moving image with good image quality even when the mobile terminal such as a mobile phone is in a communication state. That is, according to the present invention, it is possible to construct a communication system that can always perform stable video streaming in a mobile environment.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a server for streaming distribution of moving image data and a mobile terminal that receives and reproduces moving image data distributed from this server in the present invention.
FIG. 2 is a flowchart showing the flow of streaming distribution of moving image data performed between the distribution apparatus and the DO terminal in the present invention.
FIG. 3 is a flowchart showing a flow of processing performed when a DO terminal is activated conventionally.
FIG. 4 is a diagram illustrating a relationship between a used slot length, a modulation scheme to be implemented, and error tolerance with respect to each transfer rate.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Distribution apparatus, 2 ... Portable terminal (mobile communication terminal), 11 ... Traffic channel allocation part, 12 ... Channel allocation part, 13 ... Real-time request | requirement confirmation part, 14 ... Terminal reception state judgment part, 21 ... Movie streaming request part , 22 ... Real-time request unit, 23 ... Display unit, 24 ... Reception state check unit

Claims (3)

A mobile communication terminal that receives video data streamed from a distribution device that provides information and reproduces the video data,
Receiving means for receiving the video data using an assigned communication channel;
Real-time request means for requesting real-time performance for video data streamed from the distribution device;
During streaming distribution of the video data, measuring means for measuring the reception state at a specified time interval;
A mobile communication terminal comprising switching means for switching to a communication channel different from the communication channel and receiving the moving image data when the reception state is deteriorated with respect to streaming delivery that requires real-time performance . A distribution device for streaming distribution of moving image data to a mobile communication terminal,
Receiving means for receiving, from the mobile communication terminal, a distribution request signal for requesting streaming distribution of the moving image data, and a real time request signal for requesting real time property for the moving image data to be distributed by streaming;
Allocating means for allocating a communication channel for performing streaming distribution of the requested moving image data,
When the receiving means receives the real time request signal, the assigning means assigns a communication channel different from the communication channel. Detecting means for detecting communication quality of the communication channel;
The distribution apparatus according to claim 2, further comprising a switching unit that switches to the different communication channel when communication quality of a communication channel during communication deteriorates.

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