KR20150124796A - A method and apparatus for controlling data transmitting for universal serial bus communication in a radio environment - Google Patents

Abstract

In the present invention, a method for controlling a data transmission for a universal serial bus (USB) communications in a wireless network comprises the processes of: verifying whether or not a remaining time exists after transmitting data corresponding to the current data storage amount of a wireless device based on information about an available time for transmitting the data to the wireless device which is received from the wireless device providing an access to the wireless network to a device for performing the USB communications; and determining a change of a data transmission rate by using the current data storage amount and the previous data storage amount of the wireless device if the remaining time exists.

Description

Technical Field [0001] The present invention relates to a method and apparatus for controlling data transmission for USB communication in a wireless environment,

The present invention relates to a method and apparatus for controlling data transmission for USB (Universal Serial Bus) communication in a wireless environment.

When USB (Universal Serial Bus) communication is performed through a wireless network, the wireless environment can not guarantee a fixed bandwidth for USB communication such as a wired environment due to the characteristics of sharing the bandwidth by all peripheral devices. Therefore, when USB communication is performed without considering the state of the wireless network, data for USB communication may be lost.

The present invention proposes a method and apparatus for controlling transmission traffic of a USB device in consideration of a buffer state of a wireless device providing connection to the wireless network during USB communication through a wireless network.

A method according to an embodiment of the present invention comprises: A method for controlling data transmission for USB (Universal Serial Bus) communication in a wireless network, the method comprising: transmitting, from a wireless device providing a connection to the wireless network to a device that performs USB communication, Determining whether there is a remaining time after data transmission corresponding to a current data storage amount of the wireless device based on the available time information; if the remaining time exists, And determining a change in the data transmission rate using the data transmission rate.

Another method according to an embodiment of the present invention comprises: A method of controlling data transmission for universal serial bus (USB) communication in a wireless network, the method comprising the steps of: a wireless device supporting connection to the wireless network, And transmitting information on the data transmission available time to the device that is to perform the USB communication if the data storage amount is less than a predetermined threshold value.

An apparatus according to an embodiment of the present invention includes: An apparatus for controlling data transmission for universal serial bus (USB) communication in a wireless network, the apparatus comprising: a wireless device providing a connection to the wireless network to a device that performs USB communication through a transceiver unit; And determining whether there is a remaining time after data transmission corresponding to the current data storage amount of the wireless device based on the data transmission available time information of the wireless device, And a rate control unit for determining the change of the data transmission rate using a data storage amount.

Another apparatus according to an embodiment of the present invention includes: An apparatus for controlling data transmission for universal serial bus (USB) communication in a wireless network, the apparatus comprising: a wireless device that supports connection to the wireless network; And a control unit for controlling the transmission / reception unit to transmit the information on the data transferable time to the USB communication device if the data storage amount is less than a predetermined threshold value.

The present invention relates to a method and apparatus for controlling a packet loss rate and a packet loss rate by adaptively adjusting a transmission rate of USB transmission traffic to the wireless device in consideration of a buffer status of a wireless device providing connection to the wireless network during USB communication through a wireless network, The delay time is reduced and the speed can be adaptively controlled according to the situation.

FIG. 1 is a diagram for explaining a data transfer rate supported by USB 2.0 applied to an embodiment of the present invention; FIG.
2 is a block diagram of a USB device that performs USB communication according to an embodiment of the present invention.
FIG. 3A is an example of an operation flow chart for determining a change in data transmission speed of a USB device supporting USB 2.0 according to an embodiment of the present invention,
FIG. 3B is a flowchart illustrating an operation of changing a data rate of a USB device supporting USB 2.0 according to an exemplary embodiment of the present invention,
FIG. 4A is a flowchart illustrating a flow of a method for determining a change in a data transmission rate of a USB device supporting USB 3.0 according to an exemplary embodiment of the present invention,
4B illustrates an example of an operation flow chart for changing a data transmission speed of a USB device supporting USB 3.0 according to an embodiment of the present invention,
5A and 5B are graphs showing effects of speed control of a USB device according to an embodiment of the present invention,
6A and 6B are graphs showing other effects in speed control of a USB device according to an embodiment of the present invention.

The operation principle of the preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. The same elements shown in the drawings are denoted by the same reference numerals even though they are shown in different drawings. In the following description of the present invention, detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention unclear. The detailed description thereof will be omitted. The following terms are defined in consideration of the functions of the present invention, and these may be changed according to the intention of the user, the operator, or the like. Therefore, the definition should be based on the contents throughout this specification.

Generally, USB communication uses time-driven data scheduling. In this case, a sub-frame occurs every 1 ms, and data to be transmitted is defined internally for each sub-frame.

The data transmission speed of the USB communication is determined according to the USB protocol.

FIG. 1 is a diagram for explaining a data transfer rate supported by USB 2.0 according to an embodiment of the present invention.

Referring to FIG. 1, USB 2.0 supports two data rates, Full speed and High speed. Then, the frame is set according to the selected speed. If Full speed is selected, subframes are transmitted every 1 ms (101, 102, ...) to support a speed of approximately 12 Mbps. And, High speed can be chosen to provide faster speed than full speed. In this case, the high speed is, for example, divided into sub-frames of 1 ms (101) divided into eight micro frames, and can support a speed of about 480 Mbps.

Meanwhile, USB 3.0 supports super speed. Super speed, like high speed, uses 8 micro frames every 1 ms. However, unlike high speed, which exchanges handshake with one token for each data packet transmission, super speed uses a token and handshake to transmit a large number of data packets. . USB 3.0 and USB 2.0 each have different modules and use different ports. As a result, if the USB 3.0 port and the USB 2.0 port are used and the speed is determined, the corresponding port is used, and the other port is not used. For example, if the speed and usage of a USB 2.0 port is determined, it can not be converted to super speed of USB 3.0. In a general USB data transmission method, when a USB host recognizes an initial connection of a client through at least one USB device, the speed for communication with the client is determined based on the performance of the USB device of the client. In the case of USB 2.0, usually, the USB host recognizes the speed of the client as full speed on initial connection. In the enumeration reset step, the USB host transmits a high speed current to the bus line for data transmission. Then, the client having the capability to support the high speed transmits the response to the high speed current. Accordingly, when the USB host receives a response from at least one USB device, the USB host sets the speed for communication with the client to high-speed (480 Mbps). When the speed setting with the client is completed in the enumeration step, the speed does not change thereafter. Here, the Enumeration step corresponds to an operation in which the USB host detects and identifies USB devices, and does not directly affect the present invention, and therefore, a detailed description thereof will be omitted here.

As described above, the existing USB client does not change the speed after completing the speed setting with the client in the enumeration step. Thus, it was difficult to change the speed adaptively according to the transmission rate at which the wireless network is provided. Therefore, it is required to control the speed according to the wireless environment in USB communication.

Accordingly, in the embodiment of the present invention, in the USB communication through the wireless network, the current transmission rate situation of the wireless network at the USB layer is acquired, and the rate is adaptively changed corresponding to the transmission rate situation of the acquired wireless network And suggests ways to use it. Hereinafter, USB communication in this specification includes transmitting data generated from a USB host to a corresponding USB device through a wireless network, or conversely transmitting data generated from the USB device to the USB host through a wireless network.

2 is a block diagram of a USB device for performing USB communication according to an embodiment of the present invention. Here, the device 200 may operate as a USB device of a USB host or a client.

2, a USB device 200 according to an embodiment of the present invention includes a USB connection unit 202, a speed change determination unit 204, a speed change unit 208, and a speed setting unit 208 ).

The USB connection unit 202 establishes a connection with the Wi-Fi device 220, for example, as a wireless device providing connection to a wireless network for USB communication.

The Wi-Fi device 220 includes a buffer unit 222 for storing data received from the USB device 200 through the USB connection unit 202 and a buffer unit 222 for storing data of buffers included in the buffer unit 222 And a buffer control unit 224 for managing and controlling the buffer. The buffer unit 222 classifies and stores the data according to the type of the corresponding data. At this time, the type of the data may be classified into video and audio corresponding to real-time data, a background, and a BE (best effort). As an example, suppose that the buffer unit 222 includes buffers 222a through 222d for voice, video, background, and BE, respectively.

The buffer control unit 224 checks the data storage amount of each of the buffers 222a to 222d included in the buffer unit 224. [ If the buffer control unit 224 determines that the data storage amount of the buffer for each voice or image data among the data stored in the buffer unit 222 is less than the predetermined threshold amount, Transmission Opportunity (TxOP) may be mapped to a rate control factor and transmitted to the rate change determiner 204. The speed control factor according to the embodiment of the present invention is a factor indicating that the corresponding USB device can transmit the corresponding data for voice and image data corresponding to real-time data for a preset time, Or may be transmitted by mapping different values for each data.

Upon receiving the speed control factor of the data, the speed change determiner 204 determines whether to increase or decrease the data transmission speed corresponding to the speed control factor, and transmits the determined speed change instruction to the speed changing unit 206 ).

As a specific example, assume that the USB device 200 receives the current speed control factor for voice data. Then, the speed change determining unit 204 determines whether the amount of data (e.g., number of bytes, x) transmitted in the previous speed control parameter received prior to the reception of the current speed control factor, The data transmission rate (r _x ) according to the previous rate control factor can be calculated by Equation (1) using the total time (t _x ) required for data transmission.

Here, the initial value of x is set to a preset maximum value, and the initial value of t _x is set to a default time (ms) mapped to the previous speed control factor. At this time, the speed change determination unit 204 may store a speed control factor set differently for each of voice data and video data corresponding to real-time data, and a default time for each speed control factor. Alternatively, according to another embodiment, the rate change determination unit 204 may receive a corresponding default rate control factor time to be mapped to the rate control factor when receiving the rate control factor through the buffer control unit 224. [ The default time is defined as an exclusive time at which the data for which the corresponding speed control factor is set can be continuously transmitted to the buffer unit 222 through the USB connection unit 202. The speed control factor is set for voice and video which are real-time data, for example, and a relatively large video can be set to have a larger value than the voice. For example, the image can be set to 3.008 ms, and the voice can be set to 1.504 ms.

Then, the rate change determiner 204 determines the current data rate of the buffer unit 222 according to the previous rate control factor using the data rate according to the previous rate control factor, as shown in Equation (2) Calculate the time (t _req ) required to transmit the amount of storage.

Where d _q represents the current amount of data storage in the buffer in the Wi-Fi device 220.

Then, the speed change determination unit 204 transmits the current data storage amount of the buffer unit 222 according to the previous speed control factor at a default time mapped to the speed control factor as shown in Equation (3) below Subtracts the necessary time t _req and confirms the _reminding time t _remt after all the current data storage amount of the buffer unit 222 is transmitted.

If it is determined that the remaining time calculated according to Equation (3) is equal to or greater than 0, the speed change is determined and a speed change instruction is transmitted to the speed changing unit 206. [

Then, the speed changing unit 206 changes the current speed according to the speed change instruction. In this case, the speed changing unit 206 is determined differently according to the speed supported by the USB device. For example, assuming that the USB device 200 supports USB 2.0, the initial speed is set to Full speed. If the initial speed is set to high speed, a relatively large amount of data is stored in the Wi-Fi buffer as compared with the full speed, so that the speed change may be frequently required. Thus, in the embodiment of the present invention, the initial speed is set to Full speed for a USB device supporting USB 2.0.

 When the speed changing unit 206 receives the speed change instruction, the speed changing unit 206 determines to change the current speed from full speed to high speed, and the speed setting unit 208 Speed control. The speed setting unit 208 may change the current speed from the full speed 214 to the high speed 212 according to the control of the speed changing unit 206 or may change the data payload ) ≪ / RTI > size. Similarly, when the current speed is set to the super speed 210, the speed setting unit 208 changes the present speed of the super speed 210 according to the control of the speed changing unit 206. This will be described in detail later on.

First, when changing the initial speed of the high speed at full speed, the speed changing unit 206 sets the maximum speed of the high speed among the speeds of the high speed classified according to the size of the data payload as shown in Table 1 below. (210).

Referring to Table 1, the high speed can be classified into a speed corresponding to each of 10 data payloads in total. For a 512 byte data payload set to the highest level, the maximum transfer is 13, so it can support a maximum speed of 512 bytes * 13. Referring to Table 1, a maximum bandwidth (maximum bandwidth), a micro frame bandwidth as a transmission unit, a maximum transmission number, a remaining data amount (bytes), and a data amount that can be transmitted in a micro frame Can be mapped.

After setting the maximum speed of the high speed, the speed changing unit 206 may control the speed setting unit 208 to gradually decrease the maximum speed according to the current data storage amount of the buffer unit 222 have. That is, the size of the data payload of Table 1 is reduced.

Specifically, when the speed changing unit 206 receives the speed changing instruction from the speed changing determining unit 204, the speed changing unit 206 stores the changed current speed after changing the current speed. And, then when the speed change instruction has been received, changing the speed unit 206 during the transmission from changing the rate determining unit 204, the buffer unit 222, the current data storage amount (d _q), a previous velocity controlling factor in the And compares the previous data storage amount (d _q-1 ) of the buffer unit 222. If d _q is larger than d _{q-1 as a} result of the comparison, the data storage amount of the buffer unit 222 is increased at present. Therefore, the rate changing unit 206 sets the size of the currently set payload data to 1 And controls the speed setting unit 208 to decrease the step. If the comparison result d _q is 0, the speed setting unit 208 is controlled so as to increase the size of the currently set payload data by one level.

As another example, assuming that the USB device 200 supports USB 3.0, the initial speed is set to Super speed. Accordingly, when the speed changing unit 206 receives the speed changing instruction, the speed changing unit 206 controls the speed setting unit 208 to change the current speed of the super speed 210. Specifically, Super speed can be subdivided into a total of 15 steps (NumP: Number of Packets). Here, NumP may be defined as the amount of data that can be stored in the buffer of the USB device 200 (hereinafter, referred to as 'remaining buffer size') although not shown in the figure. For example, the amount of data that can be transmitted, that is, the number of packets, is set differently for each of 15 NumPs 1 to 15. Suppose that the larger the number of NumP, the larger the amount of data that can be transmitted.

Likewise, even when USB 3.0 is supported, the speed change instruction is received, and when the initial speed is changed, the maximum value of NumP is set to 15. The speed changing unit 206 controls the speed setting unit 208 to change the NumP corresponding to the remaining buffer size of the USB device 200 to the current speed. Thereafter, the rate changing unit 206 may gradually reduce the maximum rate according to the data amount of the Wi-fi buffer. That is, the speed setting unit 208 is controlled to change the currently stored NumP.

Specifically, when the speed changing unit 206 receives the speed changing instruction from the speed changing determining unit 204, the speed changing unit 206 stores the changed current speed after changing the current speed. And, then when the speed change instruction has been received, the speed change unit (206) to the current data storage amount (d _q) of the buffer unit 222 is obtained from the speed change determining unit 204, the previous speed control factor (D _q-1 ) of the buffer unit 222 at the time of transmission. If d _q is greater than d _{q-1 as a} result of the comparison, it means that the amount of data accumulated in the buffer unit 222 is currently increasing. Therefore, the rate changing unit 206 decrements the currently stored NumP And controls the speed setting unit 208 so as to set the speed. As a specific example, the speed changing unit 206 may set a new NumP value by subtracting (y + 1) from the current NumP after adding 1 to the current NumP parameter y (y + 1).

If the comparison result d _q is 0, a new NumP value can be set to a value obtained by subtracting (y-1) from the current NumP after (y-1) minus 1 by the current NumP parameter y.

Meanwhile, if the current speed is lowered when the amount of data stored in the buffer unit 222 continues to increase while the speed changing unit 206 continues to change the speed upon receiving the speed changing instructions, The speed changing unit 206 may control the speed setting unit 208 to return the current speed to the original state without going through the processes described above. In other words, in the case of USB 2.0, when the changed current speed, that is, the size of the payload data falls to 2 bytes or less, the speed changing unit 206 controls the speed setting unit 208 to restore the current speed at full speed can do. In the case of USB 3,0, the speed changing unit 206 may control the speed setting unit 208 to set the changed current speed to NumP '1'.

FIG. 3A is an example of an operation flowchart for determining a change in a data transmission speed of a USB device supporting USB 2.0 according to an embodiment of the present invention. For convenience of description, it is assumed that the speed change determination unit is the speed change determination unit 204 of FIG.

Referring to FIG. 3A, when the rate change determiner 204 receives the rate control factor through the Wi-Fi device in step 302, the process proceeds to step 304. At this time, the speed change determination unit 204 may receive the data storage amount of the buffer in which the data for which the speed control factor is set is stored.

 In step 304, the speed change determining unit 204 determines whether there is a remaining time after transmitting the current data storage amount of the buffer unit 222 at the default time mapped to the previous speed control factor. Here, the remaining time can be calculated according to Equation (3) described above. If it is determined that the remaining time does not exist in the default time, the rate change determining unit 204 returns to step 302 and waits for reception of the next rate control factor.

If it is determined that there is a remaining time in the default time, the speed change determining unit 204 determines a change in the data transfer speed of the USB device in step 306, .

FIG. 3B is an example of an operation flow chart for changing the data transmission speed of a USB device supporting USB 2.0 according to an embodiment of the present invention. Similarly, it is assumed that the speed changing unit is the speed changing unit 206 of FIG.

Referring to FIG. 3B, in step 308, the speed changing unit 206 receives a speed change instruction, and then proceeds to step 310. FIG. If the current speed change is initial, the speed changing unit 206 controls the speed setting unit 208 to set the current speed to the payload size corresponding to the maximum speed of the high speed at the full speed. In step 310, the speed changing unit 206 confirms the current data storage amount and the previous data storage amount corresponding to the previous speed control parameter with respect to the buffer unit 222. In step 312, the speed changing unit 206 determines whether the current data storage amount is larger than the previous data storage amount. If it is determined that the current data storage amount is smaller than the previous data storage amount, the rate changing unit 206 determines in step 314 whether the current data storage amount is '0'. If it is not '0' as a result of the check, the process returns to step 310. If it is determined that the current data storage amount is '0', the speed changing unit 206 controls the speed setting unit 208 to increase the current speed by one step in step 316. If the current speed is one of the payload sizes of the high speed, the speed changing unit 206 sets the speed setting unit 208 to change the current speed to a payload size one step higher than the current payload size . The speed changing unit 206 stores the changed current speed for changing the current speed upon receiving the next speed changing instruction. Then, the process proceeds to step 320. In step 320, if the current data storage amount of the buffer unit 222 has been transmitted from the remaining time obtained in step 304 to the changed current speed, the speed change determination unit 204 restores the full data to the full speed, Lt; / RTI > If it is determined in step 314 that the current data storage amount is not '0', the process returns to step 308 and waits for the next speed change instruction.

On the other hand, if it is determined in step 312 that the current data storage amount is smaller than the previous data storage amount, the rate changing unit 206 changes the current speed to a payload size smaller by one step than the current payload size in step 318 And controls the setting unit 208. The speed changing unit 2096 stores the changed current speed for changing the current speed upon receiving the next speed changing instruction. If the current data storage amount of the buffer unit 222 has been transmitted at the changed speed from the current speed changed in the remaining time obtained in step 304, the speed change determining unit 204 may restore the speed to a full speed in step 320, 3b.

Thereafter, when the next speed change instruction is received, the mobile terminal returns to high speed again at full speed. At this time, the speed change is performed through steps 316 and 318 in the payload size of the high speed which is the current speed changed at the time of receiving the previous speed change instruction, and then the full speed is restored by performing the step 320. [ This speed change process is repeated each time a speed change instruction is received.

FIG. 4A is an example of an operation flowchart for determining a change in data transmission speed of a USB device supporting USB 3.0 according to an embodiment of the present invention. For convenience of description, it is assumed that the speed change determination unit is the speed change determination unit 204 of FIG.

Referring to FIG. 4A, when the current speed control factor is received through the Wi-Fi device, the speed change determiner 204 checks the current speed set at the time of receiving the previous speed control factor in step 400, Go ahead. At this time, the rate change determining unit 204 may receive the data storage amount of the buffer unit of the Wi-Fi device in which the rate control factor is set.

 In step 402, the rate change determining unit 204 determines whether there is a remaining time after transmitting the current data storage amount of the buffer unit at the default time mapped to the previous rate control factor. Here, the remaining time can be calculated according to Equation (3) described above. If it is determined that the remaining time does not exist in the default time, the rate change determining unit 204 returns to step 400 and waits for the reception of the next rate control factor.

If it is determined that there is a remaining time in the default time, the speed change determining unit 204 determines a change in the data transfer speed of the USB device in step 404, and transmits a speed change instruction to the speed changing unit 206 .

FIG. 4B is an example of an operation flow chart for changing the data transmission speed of the USB device supporting USB 3.0 according to the embodiment of the present invention. Similarly, it is assumed that the speed changing unit is the speed changing unit 206 of FIG.

Referring to FIG. 4B, in step 406, the speed changing unit 206 receives the speed change instruction, and proceeds to step 408. FIG. In step 408, the rate changing unit 206 confirms the current data storage amount and the previous data storage amount corresponding to the previous rate control parameter for the buffer unit. In step 410, the speed changing unit 206 determines whether the current data storage amount is greater than the previous data storage amount. If it is determined that the current data storage amount is smaller than the previous data storage amount, the rate changing unit 206 determines whether the current data storage amount is '0' in step 412. If it is not '0' as a result of the check, the process returns to step 406. If it is determined that the current data storage amount is '0', the speed changing unit 206 controls the speed setting unit 208 to increase the current speed by one step in step 414. If the current speed change is initial, the speed changing unit 206 sets the current speed to NumP15, which is the maximum value of the super speed. In this case, the speed changing unit 206 maintains the current speed. If the current speed is one of the rest of the NumPs of the super speed except for the maximum value, the speed changing unit 206 controls the speed setting unit 208 to increase the current speed by one step than the current Nump do. The speed changing unit 2096 stores the changed current speed for changing the current speed upon receiving the next speed changing instruction. The flow advances to step 418. In step 418, if the current data storage amount of the buffer unit 222 is all transmitted at the current speed changed during the remaining time in step 402, the speed changing unit 206 stores the changed current speed as NumP 1 And the operation of FIG. 4B is terminated.

If it is determined in step 412 that the current data storage amount is not '0', the process returns to step 406 and waits for the next speed change instruction.

On the other hand, if it is determined in step 410 that the current data storage amount is smaller than the previous data storage amount, the speed changing unit 206 changes the current speed to NumP, which is one step smaller than the current NumP, ). The speed changing unit 2096 stores the changed current speed for changing the current speed upon receiving the next speed changing instruction. In step 418, if the current data storage amount of the buffer unit 222 is all transmitted at the current speed changed during the remaining time in step 402, the speed changing unit 206 stores the changed current speed as NumP 1 And the operation of FIG. 4B is terminated. Thereafter, when the next speed change instruction is received, the mobile terminal restores the changed NumP to NumP1 upon reception of the previous speed change instruction at NumP1 of Super speed. Then, in step 414 or 416, the speed is changed in the restored NumP. In step 418, the speed is restored to NumP 15 in super speed. This speed change process is repeated each time a speed change instruction is received.

Hereinafter, in the graphs of FIGS. 5A and 6B, high speed and full spped respectively refer to the case where only the high speed and the full spped are used in the current speed in the USB 2.0. PS / Basic is a situation in which the current speed is controlled only by the full speed of the full speed and the high speed according to the embodiment of FIG. 3A, and the PS / Advanced controls the current speed by the payload sizes of the high speed according to the embodiment of FIG. .

5A and 5B are graphs illustrating effects of speed control of a USB device according to an embodiment of the present invention.

5A, in the case of PS / Basic and PS / Advanced for performing adaptive speed control according to the embodiment of the present invention, while the USB device fixedly uses high speed and full speed, The success rate of data transmission is stable.

Referring to FIG. 5B, when the USB device fixedly uses high speed, the data rate increases with an increase in the number of clients, but overflow may occur in the buffer unit in the Wi-Fi device. And, if the full speed is fixed, the possibility of overflow in the buffer part of the Wi-Fi device is low, but the throughput is also low. On the other hand, in the case of PS / Advanced and PS / Basic performing adaptive rate control according to the embodiment of the present invention, as the number of clients increases, the success rate of data transmission increases steadily, The possibility of overflow is low.

6A and 6B are graphs showing other effects of speed control of a USB device according to an embodiment of the present invention. FIG. 6A shows the time required to transmit 1 GByte of data in minutes, and FIG. 6B shows the average data transmission delay time of each packet.

Referring to FIG. 6A, when the USB device uses high speed, as the data rate increases with the increase in the number of clients, the delay time is lower than when the full speed is fixedly used. However, there is a possibility that an overflow may occur in the buffer portion within the Wi-Fi device as described above. On the other hand, when the adaptive rate control according to the embodiment of the present invention is performed (PS / Advanced, PS / Basic), as the number of clients increases, the overflow may occur And the delay time is not so high as compared with the case of using the high speed.

Referring to FIG. 6B, it can be seen that, when the USB device fixedly uses high speed and full speed, the time required for data transfer between USB communication devices increases as the number of clients increases. On the other hand, in the case of PS / Advanced and PS / Basic which perform adaptive speed control according to the embodiment of the present invention, the time required for data transmission between devices to perform USB communication does not change significantly as the number of clients increases .

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments, but is capable of various modifications within the scope of the invention. Therefore, the scope of the present invention should not be limited by the illustrated embodiments, but should be determined by the scope of the appended claims and equivalents thereof.

Claims (16)

A method of controlling data transmission for universal serial bus (USB) communication in a wireless network,
The method comprising: receiving, from a wireless device providing a connection to the wireless network, a device that performs USB communication, the remaining data after data transmission corresponding to the current data storage amount of the wireless device, Checking whether there is a time,
And if the remaining time exists, determining a change in the data transmission rate using the current data storage amount and the previous data storage amount of the wireless device.
The method according to claim 1,
The data-transfer-possible-time-
Wherein the data transmission time includes at least one of information indicating whether or not the data transmission available time is set for the preset data, and a current data storage amount and the data transmission available time for the data. A method for controlling data transmission.
3. The method of claim 2,
In the checking process,
And checking whether the remaining time exists after the data transmission corresponding to the current data storage amount of the data among the data transmission available time.
The method of claim 3, wherein the step of determining the change of the data transmission rate comprises:
Acquiring a current data storage amount of the data and a previous data storage amount of the data when the remaining time exists;
And decreasing the data transmission rate by a predetermined number if the current data storage amount is greater than the previous data storage amount.
5. The method of claim 4,
Confirming that the current data storage amount is 0 if the current data storage amount is smaller than the previous data storage amount;
And increasing the data transmission rate by a predetermined number if the current data storage amount is zero.
The method according to claim 1,
Wherein the data transfer rate
And setting a current data storage amount of the buffer of the device.
A method of controlling data transmission for universal serial bus (USB) communication in a wireless network,
The method comprising the steps of: a wireless device supporting connection to the wireless network,
If the current data storage amount of the data is less than a predetermined threshold value, transmitting information on the data transmission available time to the USB communication device.
8. The method of claim 7,
The information on the data transmission available time may be, for example,
Wherein the at least one of the information indicating whether to set the data transmission enable time for the data and the current data storage amount and the data transfer enable time for the data.
An apparatus for controlling data transmission for USB (Universal Serial Bus) communication in a wireless network,
Receiving, from the wireless device providing the connection to the wireless network to the device that performs the USB communication through the transmission / reception unit, information corresponding to the current data storage amount of the wireless device Determining whether there is a remaining time after data transmission, and, when the remaining time exists, determining a change in the data transmission rate using the current data storage amount and the previous data storage amount of the wireless device.
10. The method of claim 9,
The data-transfer-possible-time-
Information indicating whether or not the data transmission available time for the preset data is set, and the current data storage amount and the data transmission available time for the data. 11. The method of claim 10,
Wherein the speed control unit comprises:
And determines whether the remaining time exists after the data transmission corresponding to the current data storage amount of the data among the data transmission available time.
12. The method of claim 11,
Wherein the speed control unit comprises:
And if the remaining time is present, acquires a current data storage amount of the data and a previous data storage amount of the data, and decreases the data transmission speed by a predetermined step if the current data storage amount is larger than the previous data storage amount .
13. The method of claim 12,
Wherein the rate control unit confirms that the current data storage amount is 0 if the current data storage amount is smaller than the previous data storage amount and increases the data transmission speed by a predetermined step if the current data storage amount is 0 .
10. The method of claim 9,
Wherein the data transfer rate
The current data storage amount of the buffer of the device.
An apparatus for controlling data transmission for USB (Universal Serial Bus) communication in a wireless network,
A wireless device that supports connection to the wireless network sets a data transmission available time for each data to be transmitted, and if the current data storage amount of the data is less than a predetermined threshold value, And controls the transmission / reception unit to transmit the data to the device that is to perform the communication.
16. The method of claim 15,
The information on the data transmission available time may be, for example,
Information indicating whether to set the data transmission enable time for the data, and at least one of a current data storage amount and a data transmission enable time for the data.

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