JPH11355294A - Communication device and communication method - Google Patents

Abstract

(57) [Summary] (With correction) [Problem] A transmission rate is variable and IEEE1394
Even if the data includes or does not include transmission band information that is not suitable for, the data is efficiently transmitted to the node connected to the IEEE 1394 bus. SOLUTION: A band measuring unit 2 of a communication device 1 measures a band of data to be transmitted and gives it to a microcomputer 13. Microcomputer 1
The band calculation unit 3 calculates a transmission band suitable for IEEE1394 from the measurement result. The band information and the measurement result extracted by the band information
Processing is performed so as to correspond to EEE1394. The band acquisition unit 4 uses at least one or both of the calculated value calculated by the band calculation unit and the processing result as a reference of the transmission band,
Further, the transmission band is acquired prior to the communication using the isochronous manager function of the receiving microcomputer 18. As a result, the communication device can obtain an optimal transmission band.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication apparatus suitable for efficiently performing data communication in an optimum transmission band with respect to a device connected by a digital interface such as IEEE 1394 which acquires a transmission band prior to communication. Related to the communication method.

[0002]

2. Description of the Related Art In recent years, in an apparatus having a digital interface, it has become possible to transfer data between all digital image devices and computers, and in particular, image data which must be transmitted in real time at a constant period. IEEE1394 high-performance serial bus having an isochronous transfer (also referred to as synchronous transfer) function effective for data transfer (The Institute of Electronics and Electrical Engineers: The Instit
ute of Electrical and Electronics Engineers, Inc.
Abbreviation for IEEE 1394)
Adopted as SI and attracted attention.

[0003] IEEE 1394 is a high-performance serial bus type communication medium, in which all nodes connected to the bus have synchronized time information. When transmitting an MPEG2 transport stream packet,
Using this time information, the timing of each transport packet is guaranteed.

In IEEE 1394, there is a synchronous transfer used for transferring data that requires a real-time system such as an MPEG2 transport stream or a digital video signal as described above, and data that does not require a real-time system. There is also an asynchronous transfer for sending these two types of transfer. IEEE139
The synchronous transfer of No. 4 operates based on a cycle (hereinafter, referred to as a cycle) every 125 μsec. In each cycle, synchronous transfer is preferentially performed, and the remaining time is used for asynchronous transfer. You.

[0005] When performing synchronous transfer in an IEEE 1394 network, a time (band) used in one cycle is obtained from a node that manages the band prior to communication. In other words, in the IEEE 1394, there is one node on the bus for managing the band used for the synchronous transfer, and the band used is obtained from this band management node. The node performing the synchronous transfer can transfer the data within the acquired band, and the data transmitted by the synchronous transfer is transmitted as a packet defined by IEEE1394. In synchronous transfer, real-time data transfer becomes possible by guaranteeing transfer of a predetermined amount of data for each cycle.

Considering the case where a digital broadcast using the MPEG2 system is received and specific stream data selected from the received data is transferred to a network or the like connected to an IEEE 1394 bus, as described above. The transmission band to be transmitted by the transmission band reservation function of IEEE 1394 is assigned to a band management node, that is, an isochronous resource manager (Isochronous resource manager).
ous Resource Mnanager: IRM), but if the received data to be transmitted is an MPEG2 transport packet, the data may not be input at a constant transmission rate. In such a case, when transmitting the data to the IEEE 1394, it is difficult to set how much transmission band should be acquired.

Normally, the transport stream packet of MPEG2 contains information indicating the transmission band in advance, and the transmission band to be transmitted to the IEEE 1394 network may be obtained using such information. Information on which such a transmission band is obtained is based on IEEE
It is not a value suitable for 1394. In addition, data that does not include information related to transmission may be received or reproduced. For this reason, it is difficult to acquire a transmission band using such information, and it is not possible to acquire a transmission band according to an input transmission rate.

Therefore, if a large transmission band is acquired using the transmission band acquisition function of 1EE1394, resources of the digital interface are wasted. Conversely, if a transmission band with a small value is acquired, transmission is hindered. There is a problem that there is a risk of doing so.

Conventionally, in view of the above problems, Japanese Patent Application Laid-Open
According to the proposal of Japanese Patent No. 307453, the band of the input data is detected, the required band when the data is transmitted on the IEEE 1394 bus is calculated, and the transmission condition is determined by comparing the band with the band obtained in advance from the IEEE 1394. When the required bandwidth exceeds the acquired bandwidth, transmission is stopped to prevent data transmission exceeding the bandwidth acquired from the communication medium, and a corresponding process on the receiving side has been proposed. However, in this case, if the required bandwidth exceeds the acquisition bandwidth, the data transmission itself is prohibited, so good data transmission cannot be performed, and no solution has been reached at present. is there.

[0010]

As described above, according to the conventional communication apparatus and communication method, when transmitting received data of an MPEG2 transport stream broadcast over an IEEE1394 network, the transmission rate included in the received data is not changed. When trying to acquire a band to be transmitted using the information shown, the information on which this transmission band is obtained is not a value suitable for IEEE1394, and may not include the information. Since the data rate may be variable, the bandwidth setting to be obtained cannot be set optimally according to the input data rate. Therefore, if a large bandwidth is obtained irrespective of this information, resources of the digital interface will be wasted, and if a small bandwidth is obtained, the transmission itself will be hindered. .

In view of the above, the present invention has been made in view of the above-mentioned problems, and has a variable transmission rate and IEEE 139.
It is an object of the present invention to provide a communication device and a transmission method capable of efficiently transmitting data to a node connected to an IEEE 1394 bus even if the data includes or does not include transmission band information that is not suitable for H.4.

[0012]

A communication device according to the present invention is a communication device that acquires a part of a transmission band of a communication medium prior to communication and performs communication based on the acquired transmission band. A band measuring unit for measuring a band of input data; a band calculating unit for calculating a transmission band suitable for the communication medium from a measurement result by the band measuring unit; and a transmission band based on the calculated value calculated by the band calculating unit. And transmission band acquisition means for acquiring the transmission bandwidth.

According to the present invention, in a communication apparatus for acquiring a part of a transmission band of a communication medium prior to communication and performing communication based on the acquired transmission band, the band measuring means is inputted to the communication apparatus. Measure the data bandwidth. The band calculation unit calculates a transmission band suitable for the communication medium from the measurement result by the band measurement unit. The band acquisition unit acquires a transmission band based on the calculated value calculated by the band calculation unit. For this reason, since the communication device can perform communication in the obtained optimal transmission band, the input data has a variable transmission rate and includes, for example, transmission band information that is not suitable for IEEE 1394 of the communication medium, Or even data that does not include the IEEE 1394
Data can be efficiently transmitted to the nodes connected to the bus.

[0014] A communication method according to the present invention is a communication method for acquiring a part of a transmission band of a communication medium prior to communication and performing communication based on the acquired transmission band. A bandwidth measurement procedure for measuring the bandwidth of the data input to the communication apparatus, a bandwidth calculation procedure for calculating a transmission bandwidth suitable for the communication medium from the measurement result obtained by the bandwidth measurement procedure, and transmission using the calculated value calculated by the bandwidth calculation procedure. And a transmission band acquisition procedure for acquiring a band.

In the present invention, the bandwidth measurement procedure and the bandwidth calculation procedure included in a communication method for acquiring a part of a transmission bandwidth of a communication medium prior to communication and performing communication based on the acquired transmission bandwidth. By performing the transmission band acquisition procedure, the communication device can perform communication in the acquired optimum transmission band, so that the input data has a variable transmission rate, for example, the IE of the communication medium.
Even with data that includes or does not include transmission band information that is not suitable for IEEE 1394, the same effect is obtained that data can be efficiently transmitted to nodes connected to the IEEE 1394 bus.

[0016]

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

FIG. 1 shows an embodiment of a communication apparatus employing a communication method according to the present invention.
2 is a block diagram illustrating the overall configuration when a network is constructed using a 1394 high-speed serial bus. It is assumed that the apparatus shown in the figure transmits an MPEG2 transport stream packet via an IEEE 1394 high-speed serial bus.

A communication apparatus 1 according to the present invention is, for example, as shown in FIG. 1, an information terminal device such as a set-top box capable of receiving digital broadcast data of the MPEG2 system, a streamer for outputting reproduced data of the MPEG2 system, and the like. As a recording / reproducing means. The communication device 1 is configured to be connectable to a high-speed serial bus defined by IEEE 1394. The communication device 1 has a function that can be a band management node, that is, an isochronous resource manager in the IEEE 1394. Is connected to the IEEE 139
4 networks are being constructed.

Tuner section 21 connected to communication apparatus 1
Receives, for example, MPEG-2 transmission data (hereinafter referred to as MPEG2-TSP) transmitted from the transmission means and performs processing such as demodulation processing and supplies the received data to the demultiplexer 12. I do. The demultiplexer 12 receives the data, that is, all the MPEG2-TS transmitted by broadcasting.
From P, a packet corresponding to a program to be transmitted or decoded by IEEE 1394 is selected, and a transport stream packet corresponding to the selected program is transmitted to a band measuring unit 2, a band information extracting unit 5, and a content change in the communication apparatus 1. This is given to the detection unit 7 and the format conversion unit 14.

The bandwidth measuring unit 2 in the communication device 1 receives the MP input from the demultiplexer 12 into the communication device 1.
The data rate of EG2-TSP is measured, and the measurement result is provided to the microcomputer 13.
2- Extract band information included in the TSP, and provide the extracted band information to the microcomputer 13 in the same manner. Further, the content change detecting unit 7 detects that the content transmitted by MPEG2-TSP, for example, the program being received has changed, and gives the detection result to the microcomputer 13.

The format converter 14 transmits the MP to be transmitted.
It converts EG2-TSP into a format suitable for transmission in IEEE 1394, adds necessary information, and performs conversion processing. The output of the format converter 14 is provided to the link layer 16 of the communication device 1.

The microcomputer 13 includes a transmission band calculation unit 3 for calculating a value suitable for IEEE 1394 from a measurement result value measured by the band calculation unit 2, and a transmission band acquisition unit for obtaining a transmission band in accordance with the IEEE 1394 standard. 4, a band information processing unit 6 for processing the measurement result value from the band measuring unit 2 and the information extracted by the band information detecting unit 5, and a transmission band unit 4.
A transmission band determination unit 8 that detects that the measurement result value from the band measurement unit 2 is larger than the transmission band acquired in
When the band is limited based on the result of the determination, the transmission band determining unit 8 includes a priority assigning unit 10 for assigning a priority to data to be transmitted based on a transmission partner and transmission contents.

That is, the microcomputer 13 having the above configuration has at least a transmission band calculation function, a transmission band acquisition function, a band information processing function, a transmission band determination function, a priority setting function, and the like. The control signal based on the data is transmitted to the band limiter 9, the format converter 14, the IEEE
Control corresponding to each circuit at the time of data transmission is performed by supplying the data to the link layer 16 and the display unit 11 of E1394.

The band limiting section 9 limits the transmission rate of the MPEG2-TSP to be transmitted based on the result of the transmission band determination by the microcomputer 13.
By controlling the processing such as rearrangement of data according to 4,
It is possible to limit the transmission rate.

The display section 11 is composed of, for example, an LCD or the like, and displays information relating to the execution of the transmission band limitation, information for giving notice of the execution of the band limitation, and the like.
Note that the present invention is not limited to this, and other information such as transmission band information may be displayed.

On the other hand, IEEE 139 via the communication device 1
In order to transmit data in the optimum transmission band on the network bus No. 4, a buffer memory is required. For this reason, the buffer memory 15 is also connected to the format converter 14 in the communication device 1. Buffer memory 1
5 controls the storage and writing of data in order to perform the time axis adjustment processing of the format conversion unit 14 and the time axis adjustment processing when the transmission band is limited.

Therefore, the data to be transmitted, that is, the output of the format converter 14 is supplied to a link layer (LINK) 16 defined by IEEE1394, and thereafter,
A physical layer (PHY) 17 defined by IEEE 1394 outputs the data on a network bus of IEEE 1394. This physical layer 17 is necessary for functioning as an IEEE 1394 node, and although not shown,
A port for connecting a transmission cable specified by IEEE 1394 enables an IEEE 1394 network to be constructed.

On the other hand, IEEE 1394 for data transmission
The device network as the reproducing means and the node 18 having a function that can be an isochronous resource manager include the IEEE1
It is connected via the physical layer 17 and the link layer 17 defined by 393.

Although not shown, the device node as a reproducing means is a device node which receives data transmitted, and performs display, reproduction or recording based on the data, and transmits the data supplied from the link layer 17. Data (MPEG
2-TSP), a format conversion unit 19 for performing processing such as time axis restoration, and a decoding unit 2 for performing expansion processing and the like on the output from the format conversion unit 19 to decode the output.
0. Further, although not shown, when displaying based on transmission data, the decoded output may be supplied to a monitor or the like and displayed, or when recording is performed, an appropriate It may be configured to perform processing and record.

The receiving node is a microcomputer 18 having a function that can be an isochronous resource manager defined by IEEE 1394.
Numeral 8 is capable of performing control such as Iso channel management and transmission band management when transmitting data to a plurality of other nodes connected on an IEEE 1394 network bus using the function.

The link layer 16 and the physical layer 17 are
It is defined by IEEE 1394, and has a link layer 16
Has a data communication function necessary for realizing error-free data communication between nodes in the network, and the physical layer 17 has a physical communication function necessary for executing the communication function in the IEEE 1394 system in the network. It is constructed by means. Therefore, the use of the above-described isochronous resource manager function, link layer 16 and physical layer 17, and the like enable construction of a network bus and data communication in IEEE 1394.

Next, a communication method employed in the communication apparatus of the present embodiment shown in FIG. 1 will be described in detail with reference to FIGS.

FIGS. 2 and 3 are timing charts at the time of data transmission for explaining a communication method by the communication apparatus according to the present invention. FIG. 2 shows a state where data transmission is normally performed. a) is the tuner section output data 21a,
FIG. 2B shows the demultiplexer output data 12a and FIG.
2C shows output data 17a of the communication device 1, and FIG. 2D shows output data 19a of the format converter on the receiving side.
3A and 3B show an example in which the band is limited by the communication method of the present embodiment. FIG. 3A shows the tuner unit output data 21a, FIG. 3B shows the demultiplexer output data 12a, and FIG. c) is the output data 17 of the communication device 1
3A and FIG. 3D respectively show the output data 19a of the format converter on the receiving side.

In FIG. 2 and FIG. 3, reference numeral 30 denotes all MPEG2-TSPs input to the tuner section 21. The types and configurations of the programs are A1, A2. A3
, B1, B2, B3, etc. Reference numeral 31 denotes a cycle start packet serving as a reference for synchronization of synchronous transmission (isochronous transmission) defined by IEEE1394, and reference numeral 32 denotes a cycle start packet.
Is a packet header of an isochronous packet defined by IEEE1394 and IEC61883 (MPEG2-
Common Isochronous Packet (Common Isochronous Packet) defined by TSP, digital video data (DV data), etc.
A header portion including a source packet header (hereinafter, abbreviated as SPH, which is time information defined by IEC61883) as well as a header of a ronous packet. T indicates a constant transmission delay time from the input of the MPEG2-TSP to the communication device 1 to the output of the format converter 19 on the receiving side.

Assume that digital broadcast data broadcast using the communication device 1 shown in FIG. 1 is transmitted to a certain node on an IEEE1394 network bus. Then, the data transmitted by the broadcast is received by the tuner unit 21 and subjected to processing such as demodulation and descrambling.
It is provided to the demultiplexer 12. The data transmission state at this time is transmitted at the timing shown in FIG. 2A or FIG.

In the demultiplexer 12, all MPEs
The MPEG2-TSP transmitted by the communication device 1 as an example of the present embodiment is selected from the G2-TSP. The selected data transmission state at this time is as shown in FIG.
The transmission is performed at the timing shown in FIG. still,
In this case, program A is selected and M
A1 to A5 of the PEG2-TSP are shown.

Therefore, since the program A is transmitted to another device (for example, a TV or a digital VCR connected by IEEE 1394) by the communication device 1, the MP that constitutes the program A is transmitted.
The number of EG2-TSP packets is measured by the band measuring unit 2 every 125 μs, which is, for example, the synchronous timing of the isochronous transmission of IEEE1394 (the timing at which the cycle start packet 31 is sent on the bus), and the measurement result is given to the microcomputer 13.

At the same time, the band information extraction unit 5
-Extract the band information contained in the TSP and give it to the microcomputer 13 in the same manner. The band information extracted here is, for example, a maximum transmission rate, an average rate, a minimum rate, a buffer size for smoothing the rate, and the like of MPEG2-TSP.

After that, the measurement result from the band measuring unit 2 is transmitted to the IEEE 139 by the transmission band calculating unit 3 of the microcomputer 13.
4 is normalized to a value that can be easily handled. In this case, the microcomputer 13 may be controlled to change the measurement result so that the transmission band determination unit 8 can compare the measurement result from the band measurement unit 2 and the processing result in the band information processing unit 6. .

The information extracted by the band information extracting unit 5 is transmitted to the band information processing unit 6 in the microcomputer 13 by the IEEE 13
It is normalized to a value that is easy to handle at 94. In this case, the microcomputer 13 may control the processing result so that the processing result of the band information processing unit 6 and the calculation result of the transmission band calculation unit 3 can be compared by the transmission band determination unit 8. In this case, for example, if the difference between the maximum transmission rate and the average rate is small, the processing that uses the maximum transmission rate as the processing result, or the calculation such as the average of the maximum transmission rate with the average rate or the weighted average Processing is possible.

The transmission band acquisition unit 4 uses at least one or both of the calculation result from the transmission band calculation unit 3 and the processing result from the band information processing unit 6 as a reference value of the transmission band to be acquired. , Link layer 16, physical layer 17
The transmission bandwidth is acquired from the isochronous manager unit (function) of the microcomputer 18 in accordance with the IEEE 1394 standard via the Internet. At this time, an isochronous channel number for identifying a packet to be transmitted is also acquired.

In this case, for example, when the calculation result value from the transmission band calculation unit 3 and the processing result value from the band information processing unit 6 are significantly different, the larger or smaller transmission band is adopted. Or a process such as averaging both values, and the transmission band may be determined based on the processing result.

FIG. 1 shows a case where the isochronous manager section of the microcomputer 18 of the IEEE 1394 network is mounted on the receiving device (microcomputer 18) connected by the IEEE 1394 bus, but the present invention is not limited to this. Instead, the isochronous manager unit may be configured to be mounted on any of the transmitting device, the receiving device, and the third device.

When the agreement of the isochronous channel number and the transmission speed of the packet transmitted between the transmitting device and the receiving device is completed, the MPEG2-TSP
Is ready for transmission.

Then, in the MPEG2-TSP, the time information (SPH) on the IEEE 1394 bus is added by the format converter 14 and the source packet (Source Packe) is added.
t, hereinafter referred to as SP). The SP
H is a value obtained by adding a constant transmission delay T to the time when the MPEG2-TSP is input to the communication device 1. further,
The format conversion unit 14 uses the buffer memory 15 to divide the SP into several parts, freeze some SPs, increase or decrease the size of the isochronous packet transmitted within 125 μs, and change the transmission rate to the acquired bandwidth. Adjust so that it always fits inside. That is, it is determined whether some of the SPs are connected or the SPs are equally divided into 2, 4, and 8 according to the transmission band obtained from the IRM. FIG. 2B or FIG. 3B shows a state in which the SP is not divided nor frozen.

In the format conversion section 14, FIG.
Alternatively, as shown in FIG.
By adding a PH, and further adding a CIP header and an isochronous header, an isochronous packet in IEEE1394 is formed. The isochronous header to be added may be configured to be added by the link layer 16.

Thereafter, the isochronous packet is transmitted as shown in FIG.
(C) or the physical layer 1 on the receiving side via the link layer 16 and the physical layer 17 on the transmitting side at the timing shown in FIG.
7 is transmitted.

The physical layer 17 on the receiving side and the link layer 1
7 is transmitted to the format conversion unit 1
9 given. The format conversion unit 19 restores the MPEG2-TSP by performing the reverse conversion process of the format conversion unit 14 on the transmission side, and restores the SPH value and the IEEE
The time axis of MPEG2-TSP is also restored from the time on the E1394 bus.

Thereafter, the transmission side communication apparatus 1 stores the MPEG2
-MPEG delayed by transmission delay T after TSP input
The 2-TSP is sent from the format conversion unit 19 on the receiving side to the decoding unit 20, and is decoded by the decoding unit 20. At this time, the format converter 19 on the receiving side
2 (d) or FIG. 3 (d).

When the transmission of the program being transmitted (program A in this example) is stopped and, for example, the transmission of program B is newly started, or when the transmission of program B is added, the contents of the communication device 1 The detecting unit 7 detects this, and executes the same procedure for the program B as for the program A. However, when the transmission of the program A is stopped and the program B is newly transmitted, the transmission band and the isochronous channel acquired by the transmission band acquisition unit 4 for the program A are released, and the program B is newly transmitted. May be obtained again, or one or both of the processing result values from the transmission band calculation unit 3 or the band information processing unit 6 may indicate that the transmission bands of the program A and the program B are substantially equal. In this case, the transmission band and the isochronous channel acquired for the program A may be controlled to be reused for the program B.

MPEG2-TSP input to the communication device 1
When the transmission band determining unit 8 determines that the transmission rate of the transmission band exceeds the acquired transmission band, the band limiting unit 9 is provided with a determination result indicating this, and the band is limited to the band limiting unit 9. Notify you to In this case, as a determination method, there is a method of comparing the value calculated by the transmission band calculation unit 3 with the acquired band from the measurement result from the band measurement unit 2 and making a determination.

When there are a plurality of transmitted isochronous packets, the priority assigning section 10 assigns priority to the isochronous packets according to the transmission destination.
For example, the priority may be determined so that the isochronous packet to the VCR being recorded has the highest priority, and the priority to the transmission to the TV, the reproduction data of the VCR, and the like is lower. When the user sets a priority, a setting priority corresponding to the priority may be adopted, or when a priority is added to the data itself, the priority may be adopted. good.

The band limiting unit 9 limits the transmission of the MPEG2-TSP based on the priority in the priority assigning unit 10.

As an actual transmission restriction method, for example,
When the format conversion unit 14 of the communication device 1 performs read control by the buffer memory 15, the MPEG2-TSP that has temporarily exceeded the acquisition band can be converted to the format shown in FIG.
As shown in (c), the transmission bandwidth is limited by sequentially turning the transmission backward.

In this case, if the delayed MPEG2-TSP exceeds the capacity of the buffer memory 15 or lags behind the transmission delay T, the format converter 19 on the receiving side cannot restore the MPEG2-TSP normally. Therefore, MPEG2 which constitutes an isochronous packet to a device whose priority is set higher by the priority assigner 10
The TSP thins out MPEG2-TSPs sent to other lower priority devices without delay. In this case, if the sum of the transmission bands of all the isochronous packets being transmitted is smaller than the transmission band on the IEEE 1394 bus, the band may not be limited.

If the transmission band determining unit 8 continues to exceed the band obtained for a certain period of time or more, the transmission band obtaining unit adds the current band to the current band or temporarily sets the current band. May be released to perform control such as re-acquisition from the isochronous manager section of the microcomputer 18.

In the present embodiment, when the transmission data exceeds the acquired transmission band or when the transmission is restricted, a display showing the contents thereof is displayed on the display unit 11 by the display control by the microcomputer 13. Display. This allows the user to recognize the transmission state at the time of transmission.

Therefore, according to the present embodiment, the IE
In an IEEE 1394 network, even if the information on which the transmission band is obtained is not a value suitable for IEEE 1394 and the information pertaining to the transmission rate is not included, an appropriate transmission band can be obtained. The data transmission can be performed efficiently by not wasting the resources and avoiding hindrance to the transmission itself.

In the embodiment according to the present invention,
The case where the communication device 1 is configured as a broadcast receiver based on MPEG2-TSP has been described. However, the present invention is not limited thereto. For example, the communication device 1 may be configured as a digital streamer such as a digital VHS recording MPEG2-TSP. The same effect can be obtained in the case of transmitting reproduction data from the digital streamer.
In this case, if the reproduction speed of the digital streamer is adopted as a reference value when acquiring the transmission band, data transmission can be performed more reliably.

[0060]

As described above, according to the present invention,
Even if the transmission rate is variable and includes or does not include transmission band information that is not suitable for IEEE 1394, the
It is possible to provide a communication device and a transmission method capable of efficiently transmitting data to a node connected to the E1394 bus.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a communication device incorporating a communication method of the present invention, and showing a schematic configuration of an IEEE 1394 network including the device.

FIG. 2 is a diagram for explaining a communication method of the device of FIG. 1;
FIG. 4 is a timing chart showing a state in which data transmission is normally performed.

FIG. 3 is a diagram for explaining a communication method of the device of FIG. 1;
FIG. 4 is a timing chart showing a state where data transmission is band-limited.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Communication apparatus, 2 ... Band measurement part, 3 ... Transmission band calculation part,
4 transmission band acquisition unit, 5 band information extraction unit, 6 band information processing unit, 7 content change detection unit, 8 transmission band determination unit,
9: band limiting unit, 10: priority ordering unit, 11: display unit, 12: demultiplexer, 13: microcomputer, 14 ...
Format converter, 15: buffer memory, 16: link layer, 17: physical layer.

Claims (7)

[Claims] 1. A communication device for acquiring a part of a transmission band of a communication medium prior to communication and performing communication based on the acquired transmission band, wherein a band measurement for measuring a band of data input to the communication device is provided. Means, a band calculating means for calculating a transmission band suitable for the communication medium from the measurement result by the band measuring means, and a transmission band obtaining means for obtaining a transmission band with the calculated value calculated by the band calculating means. A communication device characterized in that: 2. A band information extracting unit for extracting band information indicating a transmission band of the data stored in data input to the communication device, the band information being extracted by the band information extracting unit. Bandwidth information processing means for processing the obtained bandwidth information and the measurement result by the bandwidth measurement means so as to correspond to transmission by the communication medium, wherein the bandwidth calculation means performs processing by the bandwidth information processing means. The communication device according to claim 1, wherein the band information is calculated based on a result. 3. When the data input to the communication device includes at least a plurality of types of data having different contents, the communication device includes a content change detecting unit configured to detect a change in the content of the data. 2. The communication apparatus according to claim 1, wherein the transmission band acquisition unit acquires a new transmission band every time the content changes based on the detection result by the content change detection unit. 4. A transmission band determining unit that compares a band acquired by the transmission band unit with a measurement result obtained by the band measuring unit and determines whether the comparison result does not exceed the acquired band. 2. The communication apparatus according to claim 1, further comprising a band limiting unit configured to limit a band to be transmitted when a result of the determination by the band determining unit exceeds the acquired band. 5. An apparatus comprising: ranking means for prioritizing data to be transmitted, wherein the ranking means changes a degree of restriction on a transmission band by the band limiting means based on the priority. The communication device according to claim 4, wherein: 6. The communication apparatus according to claim 4, further comprising display means for displaying that transmission data is restricted by said band restriction means. 7. A communication method for acquiring a part of a transmission band of a communication medium prior to communication and performing communication based on the acquired transmission band, wherein data input to a communication device using the communication method is provided. A bandwidth measurement procedure for measuring a bandwidth of the communication medium; a bandwidth calculation procedure for calculating a transmission bandwidth suitable for the communication medium from the measurement result of the bandwidth measurement procedure; and a transmission for acquiring a transmission bandwidth using the calculated value calculated by the bandwidth calculation procedure. A communication method, comprising: a band acquisition procedure.