KR100801000B1 - Method and Apparatus for transmitting/receiving wireless data - Google Patents

Abstract

Provided are a method and apparatus for improving data transmission efficiency and transmission stability in wirelessly transmitting a large amount of data.

A wireless data transmission method according to an embodiment of the present invention, generating a data frame, transmitting the generated data frame to a receiving device through a first communication channel, and a control frame associated with the data frame from the receiving device Receiving via a second communication channel.

IEEE 802.15.3, mmWave, multichannel

Description

Method and apparatus for transmitting and receiving wireless data {Method and Apparatus for transmitting / receiving wireless data}

1 is a diagram comparing frequency bands between the IEEE 802.11 family of standards and mmWave.

2 is a diagram illustrating a process of transmitting data and ACKs thereof.

3 is a diagram showing an example of an environment to which the present invention can be applied.

4 illustrates an example of a directional radio signal.

5 illustrates one embodiment of the present invention in accordance with a No ACK policy.

6 illustrates one embodiment of the present invention in accordance with an immediate ACK policy.

7 illustrates one embodiment of the present invention in accordance with a block ACK policy.

8 is a diagram illustrating one configuration of a block ACK frame.

9 is a conceptual diagram of a communication layer that enables dual channel transmission in accordance with the present invention.

10 is a block diagram showing a configuration of a transmitting device for transmitting a large amount of multimedia data according to an embodiment of the present invention.

FIG. 11 is a block diagram showing a configuration of a receiving device for receiving a large amount of multimedia data according to an embodiment of the present invention. FIG.

(Symbol description of main part of drawing)

90: communication layer 91: upper layer

92: MAC layer 93: first PHY layer

94: main channel 95: second PHY layer

95: sub channel 100: transmitting device

110, 210: CPU 120, 220: Memory

130, 230: bus 140, 240: MAC unit

141: channel number recording unit 142: ACK policy recording unit

150, 250: first PHY unit 151, 251: first baseband processor

152, 252: first RF unit 161, 261: second baseband processor

162 and 262: second RF unit 153 and 253: first antenna

163, 263: second antenna 165, 265: channel switching unit

The present invention relates to a wireless communication technology, and more particularly, to a method and apparatus for improving data transmission efficiency and transmission stability in wirelessly transmitting a large amount of data.

Networks are becoming wireless and researches on effective transmission methods in wireless network environments have been required due to the increasing demand for large-capacity multimedia data transmission. Due to the nature of a wireless network in which multiple devices share and use a given radio resource, increasing competition is likely to waste valuable radio resources due to collisions during communication. In order to reduce the collision or loss and to transmit and receive data stably, in a wireless LAN (wireless local area network) environment, a competitive-based distributed coordination function (DCF) or a contention-free point coordination function (PCF) In the wireless personal area network (PAN) environment, a time division scheme called channel time allocation is used.

Although such a method can be applied to a wireless network to reduce collisions to some extent and provide stable communication, there is still a high possibility of collision between transmission data compared to a wired network. This is because there are many elements in the wireless network environment that inherently interfere with stable communication such as multi-path, fading, and interference. In addition, as the number of wireless networks participating in the wireless network increases, the possibility of problems such as collision and loss increases.

Such collisions require retransmissions that have a fatal adverse effect on the throughput of the wireless network. In particular, when better quality of service (QoS) is required, such as audio / video data (AV data), it is very important to secure more available bandwidth by reducing the number of retransmissions.

Furthermore, given the growing need to wirelessly transfer high-quality video, such as digital video disk (DVD) video and high definition television (HDTV) video, between various home devices, the high-quality video, which requires wide bandwidth, continues to be seamless. There is a need for a technical standard for transmitting and receiving.

Currently, a task group of IEEE 802.15.3c is pursuing a technical specification for transmitting a large amount of data in a wireless home network. This standard, called mmWave (Millimeter Wave), uses radio waves (ie, radio waves with frequencies of 30 GHz to 300 GHz) whose physical wavelengths are in millimeters for large data transmission. In the past, such a frequency band has been used as an unlicensed band for a limited number of purposes, such as for telecommunication carriers, radio astronomy, or vehicle collision prevention.

1 is a diagram comparing frequency bands between the IEEE 802.11 series standard and mmWave. IEEE 802.11b and IEEE 802.11g have a carrier frequency of 2.4 GHz and a channel bandwidth of about 20 MHz. In addition, IEEE 802.11a and IEEE 802.11n have a carrier frequency of 5 GHz and a channel bandwidth of about 20 MHz. In contrast, mmWave uses a carrier frequency of 60 GHz and has a channel bandwidth of approximately 0.5 to 2.5 GHz. Therefore, mmWave has a much larger carrier frequency and channel bandwidth than the existing IEEE 802.11 standard.

As such, when a high frequency signal having a wavelength in millimeters is used, a very high transmission rate in units of several gigabits (Gbps) can be represented, and an antenna size can be 1.5 mm or less, thereby realizing a single chip including an antenna. In addition, since the attenuation ratio in the air (attenuation ratio) is very high, there is an advantage that can reduce the interference between devices.

On the other hand, due to the high attenuation rate as described above, the communication distance is short, and since the signal is straight, there is a problem that communication is difficult to be properly performed in a non-line-of-sight environment. Therefore, in the mmWave, the former problem is solved by using an array antenna having a high gain, and the latter problem is solved by using a beam steering method.

However, in order to stably transmit predetermined data through one radio channel, as shown in FIG. 2, it is necessary to receive an acknowledgment (ACK) after transmitting some or all of the data. However, if an acknowledgment is received in a competitive or non-competitive manner during large data transmission, not only the transmission should be stopped to receive the acknowledgment but also a predetermined interframe interval (IFS) between data transmission and ACK. There is a problem of waiting for space. Furthermore, if the ACK for the data does not arrive due to the collision, the data may be retransmitted, thereby causing a sudden decrease in the overall transfer rate on the network.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a method and apparatus for more efficiently and stably transmitting and receiving mass data over a wireless channel.

The objects of the present invention are not limited to those mentioned above, and other objects not mentioned will be clearly understood by those skilled in the art from the following description.

Wireless data transmission method according to an embodiment of the present invention for achieving the above object, (a) generating a data frame; (b) transmitting the generated data frame to a receiving device through a first communication channel; And (c) receiving a control frame associated with the data frame from the receiving device through a second communication channel.

According to an aspect of the present invention, there is provided a method of receiving wireless data, the method including: (a) receiving a data frame from a transmitting device through a first communication channel; (b) generating a control frame associated with the received data frame; And (c) transmitting the generated control frame to the transmitting device through a second communication channel.

A wireless device according to an embodiment of the present invention for achieving the above object, the MAC (Media Access Control) unit for generating a data frame; A first physical unit which generates a radio signal relating to the generated data frame and transmits the radio signal to a receiving device through a first communication channel; And a second physical unit that receives from the receiving device through a wireless signal second communication channel for a control frame associated with the data frame.

According to an aspect of the present invention, there is provided a wireless device, including: a first physical unit configured to receive a radio signal relating to a data frame from a transmitting device through a first communication channel; A MAC unit for generating a control frame associated with the data frame; And a second physical unit generating a radio signal relating to the control frame and transmitting the radio signal to the transmitting device through a second communication channel.

Specific details of other embodiments are included in the detailed description and the drawings.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various forms, and only the present embodiments are intended to complete the disclosure of the present invention, and the general knowledge in the art to which the present invention pertains. It is provided to fully convey the scope of the invention to those skilled in the art, and the present invention is defined only by the scope of the claims. Like reference numerals refer to like elements throughout. Hereinafter, with reference to the accompanying drawings illustrating a method according to an embodiment of the present invention.

In the present invention, when data is transmitted and received using a high frequency (for example, 60 GHz) band, a main channel of a plurality of communication channels is used for data transmission, and a sub channel is used for a control frame (eg, ACK) related to data transmission. It is intended to propose a technique used for transmitting and receiving. In this case, the main channel may be responsible for unidirectional communication for large data transmission, and the subchannel may be responsible for bidirectional communication for transmitting and receiving control frames. This concept is hereinafter defined as dual channel transmission. In addition, the data transmitted is asynchronous data (synchronous data), synchronous stream data (synchronous stream data) regardless of.

3 is a diagram illustrating an example of an environment to which the present invention can be applied. The source device 21 transmits a high frequency radio signal containing high capacity multimedia data to the peripheral devices 22, 23, 24 through a main channel. The source device 21 is a device that provides multimedia data such as video and / or audio. The source device 21 may be a set-top box, a digital television (DTV), a digital video disk player, or the like. The peripheral devices 22, 23, and 24 are devices that receive the multimedia data and display or store the multimedia data, and may be a home theater 22, a DTV 23, a personal video recorder (PVR) 24, or the like. have.

Since a high frequency radio signal having a wavelength in millimeters generally has directivity, the source device 21 transmits the high frequency radio signal to the peripheral devices 22, 23, and 24 in a beam steering manner. do. A generally known beam steering concept is to transmit a radio signal by setting a predetermined direction in the transmission of a radio signal and to receive the radio signal in a predetermined direction when receiving the radio signal. For this directionality, both transmit and receive antennas consist of array antennas.

The operation of the transmitter and the receiver according to the beam steering will be described briefly as follows. First, the transmitting device generates a radio signal for transmission by carrying a baseband signal on a carrier wave, and then establishes the direction of the radio signal by adjusting the amplitude and phase of the radio signal through an array antenna. An example of the radio signal thus established is shown in FIG. 4. Referring to FIG. 4, it can be seen that the signal strength transmitted at the direction angle of 120 degrees to 150 degrees is maximized in the direction angle range of 0 degrees to 360 degrees.

Next, the receiving device receives the same radio signal having different phases from the array antenna, and then calculates a direction of arrival (DOA) through a Discrete Fourier Transform from the sum of the received signals. The combination of amplitude and phase establishes the direction of the received signal and optimizes the array antenna in the corresponding direction.

As described above, the transmitting device according to an embodiment of the present invention transmits a radio signal having a directivity to the receiving device through the main channel in a beam steering method. In this case, when the transmitting device is the source device and the receiving device is the peripheral device, the multimedia data is made in one direction from the transmitting device to the receiving device. However, unlike the main channel, the sub channel uses a signal of a lower band than the high frequency band used for the main channel. For example, the frequency of the sub-channel is one of bands where interference does not occur with the high frequency band such as the 2.4 GHz band of IEEE 802.11b, the 5 GHz band of IEEE 802.11a, and other Bluetooth communication bands (preferably, an unlicensed band). You can choose one to use. Bidirectional transmission is allowed to transmit and receive control frames such as an ACK frame and an RTS / CTS frame to the subchannel.

5 to 7 are diagrams illustrating three embodiments of a communication process according to the present invention. 5 illustrates a case where a No ACK policy is used, FIG. 6 illustrates a case where an immediate ACK policy is used, and FIG. 7 illustrates a case where a block ACK policy is used. Each case is shown.

Referring to FIG. 5, a transmitting device (or a source device) may continuously transmit a plurality of data frames 51, 52, and 53 to a receiving device (or a peripheral device). However, a predetermined IFS exists between the plurality of data frames 51, 52, and 53. The IFS may be an extended interframe space (EIFS), a distributed interframe space (DIFS), a point interframe space (PIFS), or a short interframe space (SIFS).

In this case, the data frame includes a preamble, a signal field, a MAC header, and a payload, respectively. The preamble is a signal for synchronization and channel estimation of the PHY layer (physical layer), and consists of a plurality of short training signals and long training signals. The short training signal is used for signal detection, AGC (Auto Gain Control), fine time synchronization, and integer frequency error estimation, and the long training signal is used for channel estimation and fractional frequency error estimation. In general, performing a fast and accurate estimate can greatly affect overall system performance.

The signal field includes a RATE field indicating a transmission rate, a LENGTH field indicating a length of a PHY Protocol Data Unit (PPDU), and the like. In general, a signal field is encoded by one symbol.

The preamplifier and signal fields are called a PHY header. Next to the PHY header is a MAC header, which contains various fields for media access control. In particular, the MAC header includes a field (hereinafter, referred to as an ACK policy field) for recording an ACK policy for a transmitted data frame, and the receiving device sends an ACK to the transmitting device according to the value recorded in the ACK policy field. Determine whether to transmit (No ACK policy), whether to send an ACK immediately for each data (Immediate ACK policy), or whether to send one ACK indicating the acknowledgment after receiving multiple data (Block ACK policy) Can be.

Therefore, in the case of FIG. 5, the transmitting device indicates and transmits the ACK policy field of the MAC header as No ACK and does not receive any acknowledgment from the receiving device. Such a No ACK policy may be suitably used when a channel is in good condition so that no error occurs during data frame transmission.

6, the transmitting device continuously transmits data frames 61, 62, and 63 to the main channel at IFS intervals, and the receiving device transmits an ACK frame (for each of the data frames 61, 62, and 63) to the subchannel. 64, 65, 66). In this case, the ACK frames 64, 65, and 66 may also be transmitted after the IFS has elapsed after the corresponding data frame is transmitted. Of course, different values may be used for the IFS between the data frames and the IFS between the ACK corresponding data frame and the ACK frame.

In any case, since a control frame such as an ACK frame is transmitted through a subchannel, the data can be continuously transmitted even when a separate control frame needs to be transmitted and received when a large amount of multimedia data is transmitted through the main channel. Static QoS can be guaranteed.

In the case of FIG. 6, the ACK policy field included in the MAC header of the data frames 61, 62, and 63 is immediately indicated as ACK. By the way, compared with the main channel which is located in the high frequency band and where the interference is less likely to occur, the subchannels may be interfered with by other communication channels. Accordingly, the subchannel may be selectively changed among a plurality of channels. In this case, it is necessary to promise which subchannel among the plurality of channels to communicate between the transmitting device and the receiving device.

Therefore, when the transmitting device transmits the data frames 61, 62, and 63, it selects a subchannel having a good state through channel scanning and transmits the selected channel number to the receiving device. Thereafter, transmission and reception of control data between the transmitting device and the receiving device is performed through a subchannel corresponding to the channel number. Like the ACK policy field, a field for recording the channel number (hereinafter referred to as a "channel number field") may be included in the MAC header of the data frames 61, 62, and 63.

Meanwhile, FIG. 7 shows that the transmitting device continuously transmits data frames 71, 72, and 73 to the main channel at IFS intervals, and the receiving device transmits the data frames 71, 65, and 66 to all subframes. In this case, one block ACK frame 74 indicating an acknowledgment is transmitted. In this case, the ACK policy field included in the MAC header of the data frames 71, 72, 73 is indicated by block ACK. In addition, the channel number field is represented by the identifier of the subchannel selected by the transmitting device as in FIG.

There may be various methods for indicating acknowledgment of a plurality of data frames in one block ACK frame 74. 8 shows an example of a block ACK frame 80. The block ACK frame 80, like the data frame, also includes a PHY header, a MAC header, and a payload. The payload includes a BA Control field 81 for controlling the operation of the block ACK frame, and a fragment number and a sequence number of a first MAC Protocol Data Unit (MPDU) recorded therein. A Sequence Control field 82 and a Block ACK Bitmap field 83 in which acknowledgment information for subsequent MPDUs are recorded in this order are included. That is, the first MPDU is identified through the Block ACK Starting Sequence Control field 82, and a subsequent acknowledgment of the MPDU is displayed in a bitmap.

Since the block ACK frame 74 as shown in FIG. 7 is also transmitted through the subchannel, a large amount of multimedia data can be continuously transmitted through the main channel.

9 is a conceptual diagram of a communication layer 90 that enables dual channel transmission in accordance with the present invention.

In general, the communication layer starts with a channel layer, which means a physical medium of a predetermined frequency band in which a radio signal propagates at the lowest level, and includes a PHY layer including a radio frequency (RF) layer and a baseband layer. layer), a MAC layer (Media Access Control layer), and an upper layer (upper layer). The upper layer may be a MAC or more layer and include an LLC (Logical Link Control) layer, a network layer, a transport layer, an application layer, and the like.

However, according to the present invention, since the wireless channel is divided into a main channel 94 and a sub channel 96, and frequency bands and modulation schemes of the two channels 94 and 96 may be different, both channels 94 and 96 are provided. There are two separate PHY layers (93, 94) each responsible for each). However, although the PHY layer is formed separately according to each channel, the layers of the MAC layer 92 or more for media access control may be formed as one.

10 is a block diagram illustrating a configuration of a transmitting device 100 (or a source device) for transmitting a large amount of multimedia data according to an embodiment of the present invention. The wireless device 100 includes a CPU 110, a memory 120, a MAC unit 140, a first PHY unit 150, a second PHY unit 160, a channel number recording unit 141, and an ACK policy recording unit. 142, a channel switching unit 165, a first antenna 153, and a second antenna 163.

The CPU 110 controls other components connected to the bus 130 and is responsible for processing in the upper layer 91 of FIG. Accordingly, the CPU 110 processes the received data (received MSDU; MAC Service Data Unit) provided from the MAC unit 140 or generates and provides the transmitted data (transmitted MSDU) to the MAC unit 140.

The memory 120 stores the processed received data or temporarily stores the generated transmission data. The memory may be a nonvolatile memory device such as a ROM, a PROM, an EPROM, an EEPROM, a flash memory, or a volatile memory device such as a RAM, a hard disk, an optical disk, and the like. The same storage medium, or any other form known in the art.

The MAC unit 140 generates a MAC Protocol Data Unit (MPDU) by adding a MAC header to the MSDU provided from the CPU 110, that is, the multimedia data to be transmitted. The MAC header may include an ACK policy field and a channel number field. The MAC unit 140 may include a software module implemented in a software form, a hardware module implemented in a hardware form, and an interface for relaying communication between the modules. The software module is primarily responsible for MAC functions that are not time-critical, and the hardware modules are primarily responsible for time critical MAC functions.

The ACK policy recording unit 142 determines which ACK policy (eg, No ACK, immediate ACK, block ACK, etc.) to apply to the multimedia data to be transmitted, and records the determined ACK policy in the ACK policy field. In this case, the determination may be made based on the state of the main channel, and in order to know the state of the main channel, the RXVECTOR (RHY-RXSTART.indication) provided from the first PHY unit 150 to the MAC unit 140 may be used. It may refer to RSSI (Received Signal Strength Indicator) included in).

The channel number recording unit 141 selects one of a plurality of channels as a sub channel and records a channel number corresponding to the selected sub channel in the channel number field. To this end, the channel number recording unit 141 causes the channel switching unit 165 to change the subchannel, and among the changed channels, the channel with the largest RSSI (included in the RXVECTOR and provided to the MAC unit 140) is subchannel. Can be selected.

The MAC header including the recorded ACK policy field and the channel number field is added to the MSDU (payload) provided from the CPU 110 by the MAC unit 140 to become an MPDU.

The first PHY unit 150 is used to transmit a large data frame through a main channel present in a high frequency band (eg, 60 GHz), and the second PHY unit 160 is relatively low frequency band (eg, 2.4 GHz, 5 GHz) is used to transmit and receive a control frame through a sub-channel existing in 5 GHz.

The first PHY unit 150 generates a PPDU by adding a signal field and a preamble to the MPDU provided from the MAC unit 140, converts the generated PPDU, that is, a data frame into a radio signal, and transmits the same through the first antenna 153. do. The first PHY unit 150 again generates a real radio signal from the first baseband processor 151 for processing the baseband signal and the processed baseband signal, and generates an air signal through the first antenna 153. It may be subdivided into a first radio frequency (RF) unit 152 that transmits by air.

Specifically, the first baseband processor 151 performs frame formatting, channel coding, and the like, and the first RF unit 152 performs analog wave amplification, analog / digital signal conversion, modulation, and the like. Performs the operation of. However, as described above, the first antenna 153 is configured as an array antenna to enable beam steering. When transmitting the radio signal, the first RF unit 152 may establish the directionality of the radio signal by tuning the amplitude and phase of the radio signal according to the adjustment of the array antenna 153 in advance.

The second PHY unit 150, which is responsible for the communication of the subchannels, includes a second baseband processor 161 and a second RF unit 162 and is connected to the second antenna 163. The second antenna 163 transmits and receives a radio signal having no directivity in a low frequency band compared to a radio signal transmitted to the first antenna 153.

The second baseband processor 161 included in the second PHY unit 150 receives the MPDU for the control frame generated in the MAC unit 140 and adds a signal field and a preamble to generate the PPDU. Then, the second RF unit 162 converts the generated PPDU, that is, the control frame, into a radio signal and transmits it through the second antenna 153. If there is a channel switching command by the channel switching unit 165, the second RF unit 162 changes the subchannel to the corresponding channel.

Meanwhile, the second PHY unit 150 also receives a radio signal related to a control frame transmitted from another wireless device, for example, an ACK frame, restores the ACK frame, removes the PHY header, and provides the MAC unit 140. . Then, the MAC unit 140 checks the contents of the received ACK frame, checks whether the previously transmitted data frame is normally transmitted, and prepares for retransmission of the data frame not normally transmitted.

FIG. 11 is a block diagram illustrating a configuration of a receiving device 200 (or a peripheral device) that receives a large amount of multimedia data according to an embodiment of the present invention. The configuration of the wireless device 200 is similar to that of the transmitting device 100. However, there is a slight difference in that the first wireless unit 250 of the reception device 200 may be responsible only for reception.

First, when a radio signal (having direction) regarding a data frame is received from the transmitting device 100 through the first antenna 253 which is an array antenna, the array antenna is optimized to maximize the reception performance. The direction of the radio signal to be established is established.

To this end, the first RF unit 252 receives the same radio signals having different phases from the array antenna, and then calculates a direction of arrival (DOA) through a Discrete Fourier Transform from the sum of the received signals. do. Then, the direction of the received signal is established through the combination of amplitude and phase.

The received radio signal is recovered by the first RF unit 252 into a data frame, that is, a PPDU, and transmitted to the first baseband processor 251. The first baseband processor 251 is configured with a PHY header (preamble) of the PPDU. And the MPDU generated after removing the signal field) to the MAC unit 240.

MAC unit 240 reads the MAC header of the MPDU. At this time, the MAC unit 240 checks the ACK policy field included in the MAC header, determines the type of the ACK frame for the received data frame, and prepares for transmission of the determined ACK frame. In addition, the channel number field is checked to cause the channel switching unit 265 to transmit a channel switching command to the second RF unit 262 when the channel number field is not the current subchannel. Accordingly, the second RF unit 262 changes the subchannel to the channel recorded in the channel number field, and the subsequent control frame (including the ACK frame) is transmitted and received through the changed subchannel.

Although the above has described data transmission through a wireless channel, the present invention can also be applied to data transmission through a wired channel.

The various illustrative logic blocks, modules, and circuits described in connection with the embodiments disclosed herein are general purpose processors, digital signal processors (DSPs), application specific integrated (ASIC) designed to perform the functions described herein. circuit, field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic device, discrete hardware components, or any combination thereof. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented in a combination of computing devices, eg, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other configuration.

Although embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains may implement the present invention in other specific forms without changing the technical spirit or essential features thereof. I can understand that. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

If large data is transmitted through one broadband channel and various control frames including various ACK frames are received through the same channel, efficient transmission of large data is not guaranteed. This is because not only the transmission of the data should be stopped during the reception of the control frame, but the data may be retransmitted if the ACK frame is not received for some reason.

In view of the above problem, the present invention allows a large amount of data to be continuously transmitted through a wideband main channel, and a control frame with a small data size can be transmitted and received in both directions through a relatively narrowband subchannel.

Compared to conventional transmission of a large amount of data through one wideband channel, the present invention only requires a small band (narrowband) additionally, but its transmission efficiency and OoS are significantly increased.

Claims (34)

(a) generating a data frame; (b) transmitting the generated data frame to a receiving device through a first communication channel; And (c) receiving a control frame associated with the data frame from the receiving device through a second communication channel,  Wherein the frequency band of the first communication channel is higher than the frequency band of the second communication channel, and the bandwidth of the first communication channel is wider than the bandwidth of the second communication channel. The method of claim 1, wherein the data frame is A wireless data transmission method comprising asynchronous data or synchronous stream data. delete The method of claim 1, wherein the first communication channel comprises a 60 GHz band. The method of claim 1, wherein the second communication channel comprises a 2.4 GHz band or a 5 GHz band. The method of claim 1, wherein the first communication channel is a directional unidirectional channel and the second communication channel is a bidirectional channel having no directionality. The method of claim 1, wherein the control frame A method of transmitting wireless data that is an immediate acknowledgment frame or a block acknowledgment frame. The method of claim 7, wherein The Media Access Control (MAC) header of the data frame includes a field in which an ACK policy is recorded. The method of claim 8, wherein the ACK policy A method of transmitting wireless data that is No ACK, Immediate ACK, or Block ACK. The method of claim 1, The MAC header of the data frame includes a field in which a channel number corresponding to the second communication channel is recorded. (a) receiving a data frame from a transmitting device over a first communication channel; (b) generating a control frame associated with the received data frame; And (c) transmitting the generated control frame to the transmitting device through a second communication channel, The frequency band of the first communication channel is higher than the frequency band of the second communication channel, and the bandwidth of the first communication channel is wider than the bandwidth of the second communication channel. delete 12. The method of claim 11, wherein said first communication channel comprises a 60 GHz band. 12. The method of claim 11, wherein said second communication channel comprises a 2.4 GHz band or a 5 GHz band. 12. The method of claim 11, wherein the first communication channel is a directional unidirectional channel and the second communication channel is a bidirectional channel having no directionality. The method of claim 11, wherein the control frame A method of receiving wireless data that is an immediate ACK frame or a block ACK frame. The method of claim 11, The MAC header of the data frame includes a field in which a channel number corresponding to the second communication channel is recorded. The method of claim 17, And switching to the second communication channel corresponding to the channel number. A media access control (MAC) unit for generating a data frame; A first physical unit which generates a radio signal relating to the generated data frame and transmits the radio signal to a receiving device through a first communication channel; And And a second physical unit for receiving from the receiving device via a second communication channel a radio signal relating to a control frame associated with the data frame. The method of claim 19, And an array antenna for establishing the direction of the radio signal with respect to the data frame. The method of claim 19, wherein the first physical unit and the second physical unit A wireless device comprising a baseband processor and an RF unit. 20. The wireless device of claim 19 wherein the frequency band of the first communication channel is higher than the frequency band of the second communication channel and the bandwidth of the first communication channel is wider than the bandwidth of the second communication channel. 23. The wireless device of claim 22 wherein the first communication channel comprises a 60 GHz band. 23. The wireless device of claim 22 wherein the second communication channel comprises a 2.4 GHz band or a 5 GHz band. 20. The wireless device of claim 19 wherein the first communication channel is a directional unidirectional channel and the second communication channel is a bidirectional channel having no directionality. The method of claim 19, wherein the control frame A wireless device that is an immediate ACK frame or a block ACK frame. A first physical unit for receiving a radio signal relating to a data frame from a transmitting device through a first communication channel; A MAC unit for generating a control frame associated with the data frame; And And a second physical unit for generating a radio signal relating to the control frame and transmitting the radio signal to the transmitting device through a second communication channel. The method of claim 27, And an array antenna for establishing directivity for receiving the wireless signal. The method of claim 27, wherein the first physical unit and the second physical unit A wireless device comprising a baseband processor and an RF unit. 28. The wireless device of claim 27 wherein the frequency band of the first communication channel is higher than the frequency band of the second communication channel and the bandwidth of the first communication channel is wider than the bandwidth of the second communication channel. 31. The wireless device of claim 30 wherein the first communication channel comprises a 60 GHz band. 31. The wireless device of claim 30 wherein the second communication channel comprises a 2.4 GHz band or a 5 GHz band. 28. The wireless device of claim 27 wherein the first communication channel is a unidirectional channel having a direction and the second communication channel is a bidirectional channel having no direction. The method of claim 27, wherein the control frame A wireless device that is an immediate ACK frame or a block ACK frame.

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