KR20100062881A - A method for changing a communication link between source devices and sink devices - Google Patents

Abstract

PURPOSE: A method for changing a communication link between source devices and sink devices is provided to set a first priority manual source device and communication link in a second up-link period by a first priority sink device. CONSTITUTION: In a first downlink period, an uplink period allocation message is broadcasted to sink devices(224) and manual source devices(216). In a first uplink period, a link setting message is broadcasted to all source devices in a network. A second downlink period, an active source device(212) relays the link setting message to the all sink devices. In a second uplink period, a first priority sink device(222) and a first priority source device(214) sets a communication link.

Description

A method for changing a communication link between source devices and sink devices}

The present invention relates to a method and apparatus for changing a communication link between source devices and sink devices.

Wireless Home Digital Interface (WHDI) is a technology that uses 20MHz bandwidth to deliver uncompressed 720p and 1080i video up to 30m away over a 5GHz wireless band.

FIG. 1 illustrates a method of changing a communication link between a source device and a sink device in a conventional WHDI based network.

In FIG. 1, the source device 1 110 and the sink device 1 130 are connected by a solid line, indicating that a communication link is established between the source device 1 110 and the sink device 1 130. The source device 1 110 may stream audio data, video data, and the like to the sink device 1 130 through the communication link configured as described above.

Further, the source device 2 120 and the sink device 1 130 are connected by a dotted line, indicating that a communication link may be established between the source device 2 120 and the sink device 1 130.

In this case, since the source device 1 110 and the source device 2 120 cannot establish a communication link with the sink device 1 130 at the same time, a communication link is established between the source device 2 120 and the sink device 1 130. In order to set, the communication link established between the source device 1110 and the sink device 1130 must be released.

The WHDI 0.6 standard document allows changing the communication link between the source device and the sink device as in the example above.

It is an object of the present invention to provide a method and apparatus for changing a communication link between source devices and sink devices.

 Source device in a network scheduled to repeatedly cross the uplink period for uplink transmission and the downlink period for downlink transmission according to an embodiment of the present invention for achieving the above object. The method for changing the communication link between the devices and the sink devices may be performed by the active source device in which the communication link is established with the highest priority sink device which is one of the sink devices in the first downlink period. Broadcasting, to the sink devices and the passive source devices, an uplink interval assignment message allocated by the source devices for use; in a first uplink period, the highest passive source device, which is one of the passive source devices, is the highest priority. Link establishment message for establishing a communication link with the sink device to all source devices in the network. Broadcasting; In a second downlink period, relaying, by the active source device, the received link establishment message to all sink devices in the network; And in the second uplink interval, the first priority sink device establishing a communication link with the first priority passive source device.

Preferably, the first priority sink device establishing a communication link with the first passive source device may include receiving a response to the link establishment message to all source devices in the network and communicating with the active source device. And performing a link response message that includes a request to release the link and a request to establish a communication link with the first-passive passive source device.

Preferably, the message broadcast in the first downlink period and the second downlink period have a first message format, and the message broadcast in the first uplink period and the second uplink period may include a second message. With a message format, the first message format is generated modulated in a different manner than the second message format.

Preferably, the link establishment message includes message type information indicating that the type of the link establishment message is for establishing a communication link between a source device and a sink device, an identifier of the highest priority manual source device, and an identifier of the highest priority sink device. .

Preferably, the transmitting of the link establishment message transmits a link relay message including the link establishment message, an identifier of a device corresponding to a final destination of the link establishment message, and length information of an entire message.

In addition, in a network scheduled to repeatedly cross an uplink period for uplink transmission and a downlink period for downlink transmission according to another embodiment of the present invention for achieving the above object. The method for changing the communication link between the source devices and the sink devices may be performed so that, in the first uplink period, the first priority sink device, which is one of the sink devices, may use the next uplink period by the passive source devices having no communication link established. Broadcasting an uplink interval allocation request message to all source devices in the network requesting to do so; In a first downlink interval, an uplink interval assignment message for allocating the next uplink interval to the passive source devices by an active source device having a communication link established with the highest priority sink device is broadcasted to all sink devices in the network. Casting; In a second uplink interval, the first priority manual source device broadcasting a link establishment message to all the source devices for establishing a communication link with the first priority sink device; Relaying, by the active source device, the received link establishment message to all the sink devices in a second downlink period; And in the third uplink interval, the first priority sink device establishing a communication link with the first priority passive source device.

Preferably, the method for changing a communication link according to another embodiment of the present invention provides an uplink interval grant message that allows the active source device to use an uplink interval by the passive source devices in a zero downlink period. The method further includes broadcasting to all the sink devices.

Preferably, the message broadcast in the 0th downlink period, the first downlink period, and the second downlink period have a first message format, and the first uplink period, the second uplink period, and The message broadcast in the third uplink interval has a second message format, and the first message format is generated by being modulated in a different manner from the second message format.

Preferably, the establishing of the communication link with the first-passive passive source device includes: the first-priority sink device requests all of the source devices to receive a response to the link establishment message, request to release the communication link with the active source device, and It is performed by broadcasting a link response message that includes a request to establish a communication link with a top priority passive source device.

Preferably, at least one control signal is further transmitted by the first sink device in at least one uplink section other than the first uplink section, the second uplink section, and the third uplink section. The interval assignment request message is always transmitted before the at least one control signal.

In addition, a network is scheduled such that an uplink period for uplink transmission and a downlink period for downlink transmission repeatedly cross according to another embodiment of the present invention for achieving the above object. The method for changing the communication link between the source devices and the sink devices in the first uplink period, the first sink device that is one of the sink devices, the next uplink period is used by the passive source devices that the communication link is not established Broadcasting an uplink interval allocation request message to all source devices in the network requesting to be transmitted; In a first downlink interval, an uplink interval assignment message for allocating the next uplink interval to the passive source devices by an active source device having a communication link established with the highest priority sink device is broadcasted to all sink devices in the network. Casting; In a second uplink period, by the first passive source device, broadcasting a link establishment message for establishing a communication link with the first sink device to all the sink devices; And in the third uplink interval, the first priority sink device establishing a communication link with the first priority passive source device.

Preferably, the uplink interval allocation request message includes a preamble, a channel estimation sequence for estimating characteristics of a channel through which the message is transmitted, and the type of the uplink interval allocation request message indicates the next uplink interval. Message type information indicating that the passive source devices are intended to be used, a time offset for determining a start time of an uplink interval to be allocated to the passive source devices, and a duration of the uplink interval to be allocated. ).

Preferably, the channel estimation sequence consists of 16 symbols or less.

Preferably, the method for changing a communication link according to another embodiment of the present invention provides an uplink interval grant message that allows the active source device to use an uplink interval by the passive source devices in a zero downlink interval. The method further includes broadcasting to all the sink devices.

Preferably, the message broadcast in the 0th downlink period and the first downlink period has a first message format, and the message broadcast in the first uplink period and the third uplink period includes a second message. A message broadcast in the second uplink interval has a third message format generated by extracting a part of the first message format, and the first message format and the third message format are the second message format. It is modulated and generated in a different way than the message format.

Preferably, the message broadcast in the first downlink interval has a first message format, and the message broadcast in the first uplink interval and the third uplink interval has a second message format. The message broadcast in the second uplink interval has a third message format generated by extracting a part of the first message format, wherein the first message format and the third message format are different from the second message format. Is modulated by

Advantageously, said first message format comprises a header and a payload, and said third message format includes only a header, wherein a length of a header in said first message format and a length of a header in said third message format are determined. The summed length is smaller than the vertical blanking period (V-Blanking period).

Preferably, at least one control signal is further transmitted by the first sink device in at least one uplink section other than the first uplink section, the second uplink section, and the third uplink section. The interval assignment request message is always transmitted before the at least one control signal.

In addition, an uplink period for uplink transmission between a source device and a sink device and a downlink period for downlink transmission according to another embodiment of the present invention for achieving the above object. In a network system scheduled to cross repeatedly), a communication link is established with a primary sink device, which is one of the sink devices, and a communication link is not established for the next uplink section in the first downlink section. An active source device that broadcasts an uplink interval assignment message for use by passive source devices to the sink devices and passive source devices; A primary passive source device that broadcasts a link establishment message to all source devices in the network to establish a communication link with the first sink device in a first uplink period; And when the active source device relays the received link establishment message to all sink devices of the network in a second downlink period, establishing a communication link with the highest priority passive source device in a second uplink period. First priority include a sink device.

In addition, according to another embodiment of the present invention, a network system scheduled such that an uplink interval for uplink transmission and a downlink interval for downlink transmission between source devices and sink devices repeatedly cross the first uplink. A priority sink device that broadcasts an uplink interval assignment request message to all source devices in the network requesting that the next uplink interval be used by passive source devices that have no communication link established; A communication link is established with the highest priority sink device, and broadcasts an uplink interval assignment message to all sink devices in the network to allocate the next uplink interval for use by the passive source devices in a first downlink interval. Active source devices; And a highest priority passive source device that broadcasts a link establishment message for establishing a communication link with the highest priority sink device to all the source devices in a second uplink period, wherein the active source device in a second downlink period; Relays the received link establishment message to all the sink devices, and the highest priority sink device establishes a communication link with the highest priority passive source device in a third uplink period.

In addition, an uplink period for uplink transmission and a downlink period for downlink transmission are repeatedly crossed between source devices and sink devices according to another embodiment of the present invention. The scheduled network system broadcasts an uplink interval assignment request message to all source devices in the network, requesting that the next uplink interval be used by passive source devices having no communication link established in the first uplink interval. Priority sink devices; A communication link is established with the highest priority sink device, and broadcasts an uplink interval assignment message to all sink devices in the network to allocate the next uplink interval for use by the passive source devices in a first downlink interval. Active source devices; And a highest priority passive source device that broadcasts a link establishment message for establishing a communication link with the highest priority sink device to all the sink devices in a second uplink period, wherein the highest priority sink device in the third uplink period includes: Establish a communication link with the highest priority manual source device.

In order to achieve the above object, according to an embodiment of the present invention, an active source device in which a communication link is established with a priority sink device, which is one of the sink devices, in a first downlink period does not establish a communication link in a next uplink period. Broadcasting an uplink interval assignment message for use by non-passive source devices for use by the sink devices and the passive source devices; in a first uplink period, the first passive source device, which is one of the passive source devices, Broadcasting a link establishment message for establishing a communication link with the first sink device to all source devices in the network; In a second downlink period, relaying, by the active source device, the received link establishment message to all sink devices in the network; And in the second uplink period, the first priority sink device establishing a communication link with the first priority passive source device, the computer readable recording medium having a program recorded thereon for executing a method of changing a communication link. to provide.

In addition, in order to achieve the above object, another embodiment of the present invention provides a first uplink period in which a priority sink device, which is one of the sink devices, uses a next uplink period for passive source devices having no communication link established. Broadcasting an uplink interval allocation request message to all source devices in the network requesting to do so; In a first downlink interval, an uplink interval assignment message for allocating the next uplink interval to the passive source devices by an active source device having a communication link established with the highest priority sink device is broadcasted to all sink devices in the network. Casting; In a second uplink interval, the first priority manual source device broadcasting a link establishment message to all the source devices for establishing a communication link with the first priority sink device; Relaying, by the active source device, the received link establishment message to all the sink devices in a second downlink period; And in the third uplink period, the first sink device establishing a communication link with the first passive source device, the computer readable recording medium having a program recorded thereon for executing a method of changing a communication link. to provide.

In order to achieve the above object, another embodiment of the present invention provides a first uplink period in which a first priority sink device, which is one of the sink devices, uses a passive source device in which a communication link is not set in a next uplink period. Broadcasting an uplink interval allocation request message to all source devices in the network requesting to be transmitted; In a first downlink interval, an uplink interval assignment message for allocating the next uplink interval to the passive source devices by an active source device having a communication link established with the highest priority sink device is broadcasted to all sink devices in the network. Casting; In a second uplink period, by the first passive source device, broadcasting a link establishment message for establishing a communication link with the first sink device to all the sink devices; And in the third uplink period, the first sink device establishing a communication link with the first passive source device, the computer readable recording medium having a program recorded thereon for executing a method of changing a communication link. to provide.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention.

2 is a view illustrating an embodiment of a communication link changing method according to the present invention.

In a first step, an active source device 212 in which a communication link is established with a primary passive sink device 222 in a first downlink period may not set a communication link in a next uplink period. The uplink interval assignment message allocated by the passive source devices 214, 216 is broadcast to the sink devices 222, 224 and the passive source devices 214, 216.

In this case, the uplink interval allocation message may be configured in the form of a bitmap. In this case, when a predetermined field is indicated as 1, the uplink interval allocation message is configured to allocate the next uplink interval to be used by the passive source devices 214 and 216. Can be.

Here, the active source device 212 refers to a source device that is currently streaming to the highest priority sink device 222, and the highest priority sink device 222 is a sink in which a communication link is established with the active source device 212 to receive data. Device refers to a source device for which no communication link is established with any sink device (222, 224), and a primary passive source device (214) communicates with the highest priority sink device (222). The source device to which the link is to be established.

In addition, the downlink period is a period in which the source device is set to send a message to the sink device, the uplink period is a period in which the sink device is set to send a message to the source device, in one embodiment of the present invention The link period and the uplink period may be scheduled to cross repeatedly.

Meanwhile, in FIG. 2, the active source device 212 is shown to transmit an uplink interval assignment message to the highest priority passive source device 214. However, this is merely illustrated in this manner for convenience of description and the uplink interval allocation is actually performed. The message is broadcast to both the highest passive source device 214, the passive source device 216, and the sink devices 222, 224.

In the following drawings, only some of the broadcasted messages may be shown for convenience of description.

As a second step, in the first uplink interval, the priority manual source device 214 broadcasts a link establishment message for establishing a communication link with the priority sink device 222 to all source devices 212 and 216 in the network. do.

In this case, although the highest priority manual source device 214, which is the source device to which the communication link is established with the highest priority sink device 222, is shown as predetermined in FIG. 2, the highest priority manual source device 214 is not predetermined but is a passive source device. The passive source device 214 which first broadcasts the link establishment message among the fields 214 and 216 becomes the highest priority passive source device 214. That is, in FIG. 2, the passive source device 214 at the top is determined as the highest priority passive source device 214 by broadcasting a link establishment message before the passive source device 216 at the bottom.

However, there may be a case where the passive source devices 214 and 216 simultaneously broadcast a link establishment message. In such a case, a collision may occur between the passive source devices 214 and 216. Therefore, a technique for preventing such a collision can be applied to the present invention.

Meanwhile, the priority manual source device 214 may broadcast a link relay message including a link establishment message and an identifier of a device corresponding to the final destination of the link establishment message instead of the link establishment message.

The structure of the link establishment message and link relay message will be described later with reference to FIGS. 4 and 5.

As a third step, in the second downlink period, the active source device 212 relays the link establishment message received from the highest priority passive source device 214 to all sink devices 222 and 224 of the network.

At this time, even when the active source device 212 receives the link relay message from the highest priority passive source device 214, the active source device 212 does not broadcast the link relay message, but rather the link included in the link relay message. The setup message is relayed to the sink devices 222 and 224.

As a fourth step, the first priority sink device 222 receives a response to the link establishment message (Ack), the request to release the communication link with the active source device 212 in the second uplink interval, the highest priority passive source device 214 And broadcast a link response message to all source devices 212, 214, 216 of the network, the link response message including a request to establish a communication link.

As such, the link response message is received by the active source device 212 and the highest passive source device 214, respectively, and the communication link between the highest priority sink device 222 and the active source device 212 is released, and the highest priority sink device 222 is released. ) And the highest priority passive source device 214 is established.

Meanwhile, in another embodiment, after the first priority sink device 222 broadcasts a link response message including a request for releasing a communication link with the active source device 212 in the second uplink period, in a fourth step, In an uplink interval, a link response message including a request for establishing a communication link with the highest priority passive source device 214 may be broadcast.

3 is a diagram illustrating a time schedule for an embodiment of a communication link changing method according to the present invention.

In FIG. 3, the horizontal axis represents the time axis, the downlink periods are shown at the top and the uplink periods are shown at the bottom of the time axis, and the uplink periods are the downlink. It has a fairly short duration compared to the intervals. In addition, DLF is an abbreviation of the downlink frame is a frame transmitted in the downlink, ULF is an abbreviation of the uplink frame is a frame transmitted in the uplink, DLF and ULF has a different format.

For example, the DLF is composed of a header and a payload, the header includes an uplink interval allocation message, a link establishment message, and the payload includes control data for controlling operations between the source device and the sink device, and audio to be streamed to the sink device. Data, video data, and the like. In addition, the ULF may include only a link establishment message, a link response message, and the like without control data. As such, since the ULF has a smaller amount of information than the DLF, broadcasting is possible within a short duration.

On the other hand, DLF and ULF are generated by being modulated in different ways. Thus, in principle, the DLF is modulated for reading by the sink device and the ULF is modulated for reading by the source device. Therefore, even if the source device receives the DLF, the received DLF cannot be read, and even if the sink device receives the ULF, the received ULF cannot be read.

Hereinafter, the time schedule of FIG. 3 will be described in detail.

In the first downlink interval, the active source device 212 broadcasts a downlink frame containing the uplink interval assignment message to the sink devices 222, 224 and the passive source devices 214, 216.

In the first uplink interval, the highest priority manual source device 214 broadcasts an uplink frame containing a link establishment message to all source devices 212, 216 in the network.

4 is a diagram illustrating an embodiment of a link establishment message according to the present invention.

4 shows source identifier field 410 and sink identifier field 420 as information to be included in the message body of the link establishment message according to the present invention. In this embodiment, source identifier field 410 is the highest priority manual source. The identifier of the device is recorded, and the identifier of the highest priority sink device is recorded in the sync identifier field 420.

The source identifier field 410 and the sink identifier field 420 are used to specify a source device and a sink device to establish a communication link with each other.

Although not shown in FIG. 4, besides the source identifier field 410 and the sink identifier field 420, there is a field for recording message type information indicating that the type of the link establishment message is for establishing a communication link between the source device and the sink device. It may be further included in the link establishment message.

In the present embodiment, when the active source device 212 receives the link establishment message configured as described above, the active source device 212 transmits the message type information (not shown), the source identifier 410, and the sink identifier 420. Recognizing that the received link establishment message is based on establishing a communication link between the highest priority passive source device 214 and the highest priority sink device 222, and receives the received link establishment message from all sink devices 222, of the network. 224).

On the other hand, although the link establishment message is broadcast to all sink devices 222 and 224, the final destination of the link establishment message is the highest priority sink device 222 to which the communication link is to be established. Therefore, in the first uplink period, a link relay message further including a final destination of the link establishment message may be transmitted instead of the link establishment message.

5 is a diagram illustrating an embodiment of a link relay message according to the present invention.

Referring to FIG. 5, a link relay message according to an embodiment of the present invention includes a destination device identifier field 510, a length field 520, and a relay message field 530.

The destination device identifier field 510 is a field in which an identifier corresponding to a device which is the final destination of the link relay message is recorded.

The length field 520 is a field in which information on the total length of the link relay message is recorded.

The relay message field 530 is a field in which a message to be relayed is recorded. In this embodiment, the link establishment message of FIG. 3 is recorded.

3 again, all sink devices 222 and 224 of the downlink frame including the link establishment message received by the active source device 212 from the highest priority passive source device 214 in the second downlink interval. Relay to).

In the second uplink interval, the priority sink device 222 broadcasts an uplink frame containing the link response message to all source devices 212, 214, 216 of the network.

As described above, when the active source device 212 receives the link response message from the highest priority sink device 222, the active source device 212 releases the communication link with the highest priority sink device 222, and the highest priority passive source device 214 is the highest priority sink device 222. Receiving a link response message from the NW establishes a communication link with the highest priority sink device 222.

Referring to FIG. 3, in the third downlink period, the third uplink period, the fourth downlink period, the fourth uplink period, and the fifth downlink period, the highest priority manual source device 212 and the highest priority sink device 222 may be used. Communicate with each other via a communication link established with each other.

On the other hand, as described above, in principle, the source devices only support downlink transmission and uplink reception, but in the present embodiment, the source devices 212, 214, and 216 receive the downlink frame including the uplink interval assignment message. In order to transmit downlink reception, an uplink transmission including a link establishment message must be supported. In other words, the source devices 212, 214, and 216 according to the embodiment of the present invention should be able to receive and read the DLF, and generate and transmit an uplink frame.

6 is a diagram illustrating a second embodiment of a communication link changing method according to the present invention.

As a first step, all sink devices 622 may receive an uplink interval grant message that allows the active source device 612 to use the uplink interval by the passive source devices 614 and 616 in the first downlink interval. Broadcast to 624.

In a second step, an uplink interval allocation request requesting that the highest priority sink device 622 use the next uplink interval to be used by passive source devices 614 and 616 having no communication link established in the first uplink interval. Broadcast a message to all source devices 612, 614, 616 of the network.

The structure of the uplink interval allocation request message will be described later with reference to FIG. 8.

As a third step, in the second downlink interval, an uplink interval assignment message that the active source device 612 assigns the next uplink interval to be used by the passive source devices 614 and 616 is used by all sink devices in the network ( 622, 624.

As a fourth step, in the second uplink interval, the priority manual source device 614 broadcasts a link establishment message to all source devices 612, 614, and 616 for establishing a communication link with the priority sink device 622. do.

As a fifth step, in the third downlink period, the active source device 612 relays the link establishment message received from the highest priority passive source device 614 to all the sink devices 622 and 624.

As a sixth step, in the third uplink period, the priority sink device 622 receives a response to the link establishment message (Ack), a request to release the communication link with the active source device 612, and the priority passive source device 614. Broadcasts a link response message to all source devices 612, 614, 616 in the network.

7 is a diagram illustrating a time schedule for a second embodiment of a communication link changing method according to the present invention.

In the first downlink interval, the active source device 612 broadcasts a downlink frame that includes an uplink interval allow message to all sink devices 622, 624.

In the first uplink interval, the highest priority sink device 622 broadcasts an uplink frame containing the uplink interval assignment request message to all source devices 612, 614, 616 in the network.

8 is a diagram illustrating an embodiment of an uplink interval allocation request message according to the present invention.

Referring to FIG. 8, the uplink interval allocation request message according to the present invention includes a preamble, a channel estimation sequence field 810, and a data field 820.

In the channel estimation sequence field 810, a channel estimation sequence for estimating characteristics of a channel through which a message is transmitted is recorded.

The data field 820 includes a message preamble, a message type field 822, a length field 824, a message body field 826, and a PCS field.

Message type field 822 records message type information indicating that the type of the uplink interval assignment request message is for requesting the passive source devices to use the next uplink interval.

In the length field 824, information on the total length of the uplink interval allocation request message is recorded.

The message body field 826 includes an uplink start offset field 826a and an uplink duration field 826b.

In the uplink start offset field 826a, a time offset for determining a start time of an uplink period to be allocated to passive source devices is recorded.

In the uplink duration field 826b, the duration of an uplink interval to be allocated to the passive source devices is recorded.

Referring to FIG. 7, a time offset is displayed on the second downlink interval, and an uplink duration is displayed on the second uplink interval.

Description of the other fields included in the uplink interval allocation request message is described in detail in the WHDI 1.0 standard document, and thus the description of the fields is omitted.

Returning to FIG. 7, in the second downlink interval, the active source device 612 broadcasts a downlink frame containing an uplink interval assignment message to all sink devices 622, 624 in the network.

In the second uplink interval, the highest priority manual source device 614 broadcasts an uplink frame containing the link establishment message to all source devices 612, 614, 616.

In the third downlink interval, the active source device 612 relays the downlink frame including the link establishment message received from the highest priority passive source device 614 to all sink devices 622 and 624.

In the third uplink interval, the highest priority sink device 622 broadcasts an uplink frame containing the link response message to all source devices 612, 614, 616 in the network.

Meanwhile, the priority sink device 622 may further transmit control signals through the uplink periods. Thus, even if there is a control signal to be transmitted, the priority sink device 622 should first transmit an uplink period allocation request message.

For example, if the priority sink device 622 was to transmit a control signal in the first uplink period, but receives an uplink period allowance message from the active source device 612, the control that was scheduled to be transmitted in the first uplink period. The uplink interval allocation request message may be transmitted instead of the signal.

Meanwhile, in the present embodiment, the source devices 612, 614, and 616 must further support uplink transmission in order to transmit an uplink frame including a link establishment message in addition to supporting downlink transmission and uplink reception. .

9 is a diagram illustrating a third embodiment of a communication link changing method according to the present invention.

As a first step, in the first downlink interval, all the uplink interval allow message that the active source device 912 allows the passive source devices 914 and 916 to which the communication link is not established is used. Broadcast to sink devices 922, 924. As a second step, in the first uplink interval, the uplink interval allocation request message requesting that the highest priority sink device 922 make the next uplink interval available to the passive source devices 914 and 916 is used for all sources in the network. Broadcast to devices 912, 914, 916.

As a third step, in the second downlink interval, an uplink interval assignment message that the active source device 912 assigns the next uplink interval to be used by the passive source devices 914 and 916 is assigned to all sink devices in the network ( 922, 924.

In a fourth step, the priority manual source device 916 broadcasts a link establishment message to all the sink devices 922 and 924 to establish a communication link with the priority sink device 922 in the second uplink period.

In a fifth step, the first priority sink device 922 receives an acknowledgment (Ack) to the link establishment message, a request to release a communication link with the active source device 612, and the highest priority passive source device 914 in the third uplink period. And broadcast a link response message to all source devices 912, 914, 916 in the network, the link response message including a request to establish a communication link.

In FIG. 9, the highest priority passive source device 914 is farther from the active source device 912 than in FIGS. 2 and 6, so that the highest priority passive source device 914 communicates directly with the active source device 912. It can be hard. Accordingly, in the embodiment of FIG. 9, the highest priority passive source device 914 is configured to establish a communication link with the highest priority sink device 922 without performing direct communication with the active source device 912.

10 is a diagram illustrating a time schedule for a third embodiment of a communication link changing method according to the present invention.

In the first downlink interval, the active source device 912 broadcasts a downlink frame that includes an uplink interval grant message to all sink devices 922, 924.

In the first uplink interval, the highest priority sink device 922 broadcasts an uplink frame including an uplink interval allocation request message to all source devices 912, 914, and 916 of the network.

In this case, the uplink interval allocation request message may include a preamble, a channel estimation sequence, message type information, a time offset, and a duration of the uplink interval as described above.

In addition, in the WHDI 1.0 standard document, the uplink frame and the header of the downlink frame broadcast in the adjacent downlink period next to the uplink period in which the uplink frame is broadcast together include a vertical blanking period (V-Blanking period). And the length of the uplink frame and the length of the header of the adjacent downlink frame after the uplink frame is smaller than the vertical blanking interval so that the uplink frame and the downlink within the vertical blanking interval All information in the header of the frame can be broadcast.

In the present embodiment, the header of the downlink frame broadcast in the second downlink interval includes an uplink interval assignment message, so that the length of the uplink frame broadcast in the first uplink interval and the second downlink interval The sum of the lengths of the uplink interval assignment messages should be less than or equal to the vertical blanking interval.

For example, for this purpose, the channel estimation sequence in the uplink frame is generally composed of 20 symbols, but the channel estimation sequence may be composed of 16 symbols or less, and the uplink interval allocation request message included in the uplink frame is 11 bytes or less. It may be configured to.

On the other hand, the vertical blanking section is a term that will be apparent to those skilled in the art, so a detailed description thereof will be omitted.

In the second downlink interval, the active source device 912 broadcasts a downlink frame containing the uplink interval assignment message to all sink devices 922 and 924 in the network.

In the second uplink period, the highest priority manual source device 916 broadcasts a downlink header only frame (DLHF) including a link establishment message to all sink devices 922 and 924.

Here, the downlink header limited frame is generated by extracting only the header from the downlink frame and is a frame for broadcasting by the source device to the sink device.

The reason for broadcasting the downlink header confined frame in the uplink period is that the uplink period has a much shorter duration than the downlink period. However, the entire downlink frame cannot be transmitted within the short duration. Because.

In addition, in order to reduce the length of the downlink header constrained frame, the channel estimation sequence in the downlink header constrained frame may be composed of 16 symbols or less, and the link establishment message included in the downlink header constrained frame may be 11 bytes or less. Can be.

In the third uplink interval, the highest priority sink device 922 broadcasts an uplink frame including the link response message to all source devices 912, 914, and 916 of the network.

Referring to FIG. 10, although there is a third downlink interval between the second uplink interval and the third uplink interval, the active source device 912 transmits no message during this downlink interval. However, although the active source device 912 does not transmit a message in the third downlink period, audio data, video data, and the like may be streamed to the first sink device 922.

In the present embodiment, the source devices 912, 914, and 916 may support only downlink transmission and uplink reception.

11 is a diagram for explaining a fourth embodiment of a communication link changing method according to the present invention.

FIG. 11 omits the step in which the active source device 1112 broadcasts an uplink interval grant message to all sink devices 1122 and 1124 in the first downlink interval in comparison with the embodiment of FIG. 9.

Accordingly, in the first uplink period, the first sink device 1122 broadcasts an uplink interval allocation request message to all source devices 1112, 1114, and 1116 of the network.

In the present embodiment, the priority sink device 1122 may broadcast the uplink interval allocation request message independently without receiving the uplink interval grant message from the active source device 1112.

Except for this, the same description as in the embodiment of FIG. 9 will not be repeated.

12 is a diagram illustrating a time schedule for a fourth embodiment of a communication link changing method according to the present invention.

FIG. 12 shows that the active source device 1112 broadcasts a downlink frame including an uplink interval grant message to all sink devices 1122 and 1124 in the first downlink interval in comparison with the embodiment of FIG. 10. The step is omitted.

Accordingly, the first priority sink device 1122 starts broadcasting the uplink frame including the uplink interval allocation request message to all the sinks 1112, 1114, and 1116 of the network. Except for this, the same description as in the embodiment of FIG. 10 will be omitted.

On the other hand, while the embodiments so far have been described as messages are broadcast through successive uplink intervals and downlink intervals, in other embodiments the messages are broadcast through non-contiguous uplink intervals and downlink intervals. May be

For example, in FIG. 12, after the uplink interval assignment request message is broadcast in the first uplink interval, an uplink interval allocation message is broadcast in the second downlink interval. However, in another embodiment, the second downlink interval and the first downlink interval are broadcast. In the second uplink period, no message is transmitted, only audio data and video data are streamed, an uplink interval assignment message is broadcast in the third downlink interval, and a link establishment message is broadcast in the third uplink interval. May be

This may broadcast the message as soon as the source device or sink device receives the message, but in some cases it may broadcast the message after receiving the message and passing some downlink or uplink intervals. Because it may.

Meanwhile, in the related art, the communication link between the source device and the sink device may be changed, but the process of actually changing the communication link has not been defined, but through the various embodiments described in the present disclosure, the source device and the sink device may not be defined. The communication link can be effectively changed.

Meanwhile, the above-described embodiments of the present invention can be written as a program that can be executed in a computer, and can be implemented in a general-purpose digital computer that operates the program using a computer-readable recording medium.

The computer-readable recording medium may be a magnetic storage medium (for example, a ROM, a floppy disk, a hard disk, etc.), an optical reading medium (for example, a CD-ROM, a DVD, etc.) and a carrier wave (for example, the Internet). Storage medium).

So far I looked at the center of the preferred embodiment for the present invention. Those skilled in the art will appreciate that the present invention can be implemented in a modified form without departing from the essential features of the present invention. Therefore, the disclosed embodiments should be considered in descriptive sense only and not for purposes of limitation. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the scope will be construed as being included in the present invention.

FIG. 1 illustrates a method of changing a communication link between a source device and a sink device in a conventional WHDI based network.

2 is a view illustrating an embodiment of a communication link changing method according to the present invention.

3 is a diagram illustrating a time schedule for an embodiment of a communication link changing method according to the present invention.

4 is a diagram illustrating an embodiment of a link establishment message according to the present invention.

5 is a diagram illustrating an embodiment of a link relay message according to the present invention.

6 is a diagram illustrating a second embodiment of a communication link changing method according to the present invention.

7 is a diagram illustrating a time schedule for a second embodiment of a communication link changing method according to the present invention.

8 is a diagram illustrating an embodiment of an uplink interval allocation request message according to the present invention. ,

9 is a diagram illustrating a third embodiment of a communication link changing method according to the present invention.

10 is a diagram illustrating a time schedule for a third embodiment of a method of changing a communication link according to the present invention.

11 is a diagram for explaining a fourth embodiment of a communication link changing method according to the present invention.

12 is a diagram illustrating a time schedule for a fourth embodiment of a communication link changing method according to the present invention.

Claims (37)

A method of changing a communication link between source devices and sink devices in a network that is scheduled to repeatedly cross an uplink period for uplink transmission and a downlink period for downlink transmission. , In the first downlink period, an active source device in which a communication link is established with the highest priority sink device, which is one of the sink devices, sends an uplink interval assignment message for allocating the next uplink period to be used by passive source devices having no communication link established. Broadcasting to the sink devices and passive source devices; In a first uplink interval, a first priority source device, one of the passive source devices, broadcasting a link establishment message for establishing a communication link with the first sink device to all source devices in the network; In a second downlink period, relaying, by the active source device, the received link establishment message to all sink devices in the network; And In the second uplink period, the first priority sink device establishing a communication link with the first priority passive source device. The method of claim 1, Setting the communication link with the priority sink device by the priority sink device The priority sink device including all of the source devices in the network receiving a response to the link establishment message, requesting to release a communication link with the active source device, and requesting to establish a communication link with the priority passive source device. And by broadcasting a link response message. The method of claim 1, Messages broadcast in the first downlink period and the second downlink period have a first message format, and messages broadcast in the first uplink period and the second uplink period have a second message format. have, And wherein the first message format is generated modulated in a different manner than the second message format. The method of claim 1, The link establishment message is Message type information indicating that the type of the link establishment message is for establishing a communication link between a source device and a sink device, an identifier of the highest priority passive source device, and an identifier of the highest priority sink device; . The method of claim 4, wherein The step of transmitting the link establishment message And transmitting a link relay message including the link establishment message, an identifier of a device corresponding to a final destination of the link establishment message, and length information of an entire message. A method of changing a communication link between source devices and sink devices in a network that is scheduled to repeatedly cross an uplink period for uplink transmission and a downlink period for downlink transmission. , In a first uplink interval, an uplink interval allocation request message requesting that a priority sink device, which is one of the sink devices, to use a passive source device for which a communication link has not been established, uses the next uplink interval in all of the networks. Broadcasting to source devices; In a first downlink interval, an uplink interval assignment message for allocating the next uplink interval to the passive source devices by an active source device having a communication link established with the highest priority sink device is broadcasted to all sink devices in the network. Casting; In a second uplink period, the first priority source device broadcasting a link establishment message to all the source devices for establishing a communication link with the first priority sink device; Relaying, by the active source device, the received link establishment message to all the sink devices in a second downlink period; And In the third uplink period, the first priority sink device establishing a communication link with the first priority passive source device. The method of claim 6, In a 0th downlink interval, further comprising: broadcasting an uplink interval grant message to all the sink devices that the active source device allows the passive source devices to use an uplink interval; How to change communication link. The method of claim 7, wherein Messages broadcast in the 0th downlink period, the first downlink period, and the second downlink period have a first message format, and the first uplink period, the second uplink period, and the third The message broadcast in the uplink interval has a second message format, And wherein the first message format is generated modulated in a different manner than the second message format. The method of claim 6, Establishing a communication link with the highest priority passive source device The link response includes the first priority sink device receiving all of the source devices a response to the link establishment message, a request to release the communication link with the active source device, and a request to establish a communication link with the top passive source device. Characterized in that it is performed by broadcasting a message. The method of claim 6, At least one control signal is further transmitted by the first sink device in at least one uplink section other than the first uplink section, the second uplink section, and the third uplink section, The uplink interval assignment request message is always transmitted before the at least one control signal. A method of changing a communication link between source devices and sink devices in a network that is scheduled to repeatedly cross an uplink period for uplink transmission and a downlink period for downlink transmission. , In a first uplink period, an uplink interval allocation request message requesting that a priority sink device, which is one of the sink devices, to use a passive source device having no communication link established in a next uplink interval, Broadcasting to all source devices; In a first downlink interval, an uplink interval assignment message for allocating the next uplink interval to the passive source devices by an active source device having a communication link established with the highest priority sink device is broadcasted to all sink devices in the network. Casting; In a second uplink period, by the first passive source device, broadcasting a link establishment message for establishing a communication link with the first sink device to all the sink devices; And In the third uplink period, the first priority sink device establishing a communication link with the first priority passive source device. The method of claim 11, The uplink interval allocation request message is Preamble, a channel estimation sequence for estimating the characteristics of the channel on which the message is transmitted, and requesting that the type of the uplink interval allocation request message allows the passive source devices to use the next uplink interval Message type information indicating that it is intended to be used, a time offset for determining a start time of an uplink period to be allocated to the passive source devices, and a duration of the uplink period to be allocated. Way. The method of claim 12, And wherein said channel estimation sequence is comprised of 16 symbols or less. The method of claim 11, In a 0th downlink interval, further comprising: broadcasting an uplink interval grant message to all the sink devices that the active source device allows the passive source devices to use an uplink interval; How to change communication link. The method of claim 14, Messages broadcast in the 0th downlink period and the first downlink period have a first message format, and messages broadcast in the first uplink period and the third uplink period have a second message format. The message broadcast in the second uplink interval has a third message format generated by extracting a part of the first message format. And wherein the first message format and the third message format are modulated and generated in a different manner than the second message format. The method of claim 11, The message broadcast in the first downlink interval has a first message format, the message broadcast in the first uplink interval and the third uplink interval has a second message format, and the second uplink The message broadcast in the interval has a third message format generated by extracting a part of the first message format. And wherein the first message format and the third message format are modulated and generated in a different manner than the second message format. The method according to claim 15 or 16, The first message format includes a header and a payload, The third message format includes only a header, And a length obtained by adding up the length of the header in the first message format and the length of the header in the third message format is smaller than a vertical blanking period (V-Blanking period). The method of claim 11, At least one control signal is further transmitted by the first sink device in at least one uplink section other than the first uplink section, the second uplink section, and the third uplink section, The uplink interval assignment request message is always transmitted before the at least one control signal. In the network system is scheduled so that the uplink period for the uplink transmission and the downlink period for the downlink transmission between the source devices and the sink devices repeatedly intersect, A communication link is established with a primary sink device, which is one of the sink devices, and an uplink section for allocating a next uplink section in a first downlink section to be used by passive source devices having no communication link established. An active source device that broadcasts an assignment message to the sink devices and passive source devices; A primary passive source device for broadcasting a link establishment message for establishing a communication link with the first sink device to all source devices in the network in a first uplink period; And If the active source device relays the received link establishment message to all sink devices of the network in a second downlink period, the highest priority for establishing a communication link with the highest priority passive source device in a second uplink period. And a sink device. The method of claim 19, The highest priority sink device Broadcast a link response message to all source devices in the network, the link response message including a reception response to the link establishment message, a request to release a communication link with the active source device, and a request to establish a communication link with the first passive source device. And establish a communication link with said first-passive passive source device by casting. The method of claim 19, Messages broadcast in the first downlink period and the second downlink period have a first message format, and messages broadcast in the first uplink period and the second uplink period have a second message format. have, And wherein the first message format is modulated and generated in a different manner than the second message format. The method of claim 19, The link establishment message is Message type information indicating that the type of the link establishment message is for establishing a communication link between a source device and a sink device, an identifier of the highest priority passive source device, and an identifier of the highest priority sink device. The method of claim 22, The first passive source device And transmitting a link relay message including the link establishment message, an identifier of a device corresponding to a final destination of the link establishment message, and length information of an entire message in the first uplink period. In the network system is scheduled so that the uplink period for the uplink transmission and the downlink period for the downlink transmission between the source devices and the sink devices repeatedly cross, A first priority sink device that broadcasts an uplink interval assignment request message to all source devices in the network requesting that the next uplink interval be used by passive source devices that have no communication link established; A communication link is established with the highest priority sink device, and broadcasts an uplink interval assignment message to all sink devices in the network to allocate the next uplink interval for use by the passive source devices in a first downlink interval. Active source devices; And In the second uplink period, the first priority source device for broadcasting a link establishment message for establishing a communication link with the priority sink device to all the source devices, If the active source device relays the received link establishment message to all the sink devices in a second downlink period, the highest priority sink device establishes a communication link with the highest priority passive source device in a third uplink period. Network system, characterized in that. The method of claim 24, The active source device And broadcast an uplink interval grant message to all sink devices indicating that the passive source devices use an uplink interval in a zeroth downlink interval. The method of claim 24, Messages broadcast in the 0th downlink period, the first downlink period, and the second downlink period have a first message format, and the first uplink period, the second uplink period, and the third The message broadcast in the uplink interval has a second message format, And wherein the first message format is modulated and generated in a different manner than the second message format. The method of claim 24, The highest priority sink device The first priority passive source device by broadcasting a link response message including a reception response to the link establishment message, a request to release a communication link with the active source device, and a request to establish a communication link with the first passive source device; A network system, characterized by establishing a communication link. The method of claim 24, The highest priority sink device Further transmitting at least one control signal in at least one uplink interval other than the first uplink interval, the second uplink interval, and the third uplink interval, and transmitting the uplink interval assignment request message to the at least one A method for changing a communication link, which always transmits before a control signal. In the network system is scheduled so that the uplink period for the uplink transmission and the downlink period for the downlink transmission between the source devices and the sink devices repeatedly intersect, A first priority sink device that broadcasts an uplink interval assignment request message to all source devices in the network requesting that the next uplink interval be used by passive source devices for which a communication link is not established; A communication link is established with the highest priority sink device and broadcasts an uplink interval assignment message to all sink devices in the network to allocate the next uplink interval for use by the passive source devices in a first downlink interval. Active source devices; And A first priority manual source device that broadcasts a link establishment message to all the sink devices to establish a communication link with the first sink device in a second uplink interval, And said first priority sink device establishes a communication link with said first priority passive source device in a third uplink interval. 30. The method of claim 29, The uplink interval allocation request message is Preamble, a channel estimation sequence for estimating the characteristics of the channel on which the message is transmitted, and requesting that the type of the uplink interval allocation request message allows the passive source devices to use the next uplink interval Message type information indicating that it is intended to be used, a time offset for determining a start time point of an uplink period to be allocated to the passive source devices, and a duration of the uplink period to be allocated. 31. The method of claim 30, And the channel estimation sequence is comprised of 16 symbols or less. 30. The method of claim 29, The active source device And broadcast an uplink interval grant message to all sink devices indicating that the passive source devices use an uplink interval in a zeroth downlink interval. 33. The method of claim 32, Messages broadcast in the 0th downlink period and the first downlink period have a first message format, and messages broadcast in the first uplink period and the third uplink period have a second message format. The message broadcast in the second uplink interval has a third message format generated by extracting a part of the first message format. And wherein the first message format and the third message format are modulated and generated in a different manner than the second message format. 30. The method of claim 29, The message broadcast in the first downlink interval has a first message format, the message broadcast in the first uplink interval and the third uplink interval has a second message format, and the second uplink The message broadcast in the interval has a third message format generated by extracting a part of the first message format. And wherein the first message format and the third message format are modulated and generated in a different manner than the second message format. The method of claim 33 or 34, The first message format includes a header and a payload, The third message format includes only a header, And a length obtained by adding up the length of the header in the first message format and the length of the header in the third message format is smaller than a vertical blanking period (V-Blanking period). 30. The method of claim 29, The priority sink device further transmits at least one control signal in at least one uplink section other than the first uplink section, the second uplink section, and the third uplink section, and the uplink section allocation request message. The network system, characterized in that for always transmitting before the at least one control signal. A computer-readable recording medium having recorded thereon a program for executing the method of any one of claims 1 to 18.

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