WO2013187703A1

WO2013187703A1 - Communication method and communication device in wireless lan system that supports multi-bandwidth

Info

Publication number: WO2013187703A1
Application number: PCT/KR2013/005215
Authority: WO
Inventors: 유희정; 정민호; 이재승; 권형진; 이석규
Original assignee: 한국전자통신연구원
Priority date: 2012-06-13
Filing date: 2013-06-13
Publication date: 2013-12-19

Abstract

Disclosed are a communication method and a communication device in a wireless LAN system that supports multi-bandwidth. The communication method in a wide-area wireless LAN system according to one embodiment of the invention comprises: a step in which a communication device of a network that supports multi-bandwidth generates a basic frame based on either a first bandwidth having the lowest signal-to-noise ratio from among preset bandwidths, or a second bandwidth the size of which is double that of the first bandwidth; a step in which the communication device configures a duplication mode frame based on the basic frame; and a step in which the communication device transmits the duplication mode frame over a plurality of bands.

Description

Communication method and device in a wireless LAN system supporting multiple bandwidths

Described below is a communication method and apparatus for a WLAN system supporting multiple bandwidths.

The evolution of WLAN technology is proceeding in three directions.

The first direction is a technology to further increase the transmission speed, there is a WLAN technology using a 60GHz band and a WLAN technology using a 5GHz band. The second technology is a wide area WLAN technology that utilizes a frequency band of less than 1 GHz to increase coverage than the existing WLAN technology. The third direction is a technique for reducing the link setup time of the WLAN system.

Wide area wireless LAN technology supports multi-bandwidth (multi bandwidth). In a wireless communication system supporting multiple bandwidths, all terminals supporting various bandwidths can be received, and a definition of a bandwidth duplication mode (duplication) that can cover the entire communication radius of an access point (AP) is needed.

Embodiments of the present invention provide a structure of a duplication mode frame that can be received by all the terminals in the network in a wide area wireless LAN system.

Embodiments of the present invention provide a method of generating a duplication mode frame based on a bandwidth having the lowest signal-to-noise ratio among a plurality of bandwidths available in a wide area WLAN system.

In addition, embodiments of the present invention to provide a duplication mode frame configuration and transmission method suitable for a wide area wireless LAN system.

Embodiments of the present invention provide a communication method and apparatus capable of receiving control frames in all bandwidths and communication distances of a wide area wireless LAN system.

In a communication method of a wide area wireless LAN system according to an embodiment, a communication device of a network that supports multi-bandwidth may include a first bandwidth having a lowest signal-to-noise ratio among preset bandwidths, and two of the first bandwidth. Generating a basic frame based on one of the second bandwidths having a double size, constructing a duplication mode frame based on the basic frame, and performing a plurality of bands Transmitting a duplication mode frame.

A communication apparatus of a wide area wireless LAN system according to an embodiment may include a basic apparatus based on one of a first bandwidth having a lowest signal-to-noise ratio among preset bandwidths and a second bandwidth that is twice the first bandwidth. Multiple bandwidths of the duplication mode frame through a basic frame generation unit for generating a frame, a duplication mode frame configuration unit for configuring a duplication mode frame based on the basic frame, and a plurality of bands It includes a frame transmission unit for transmitting to a network supporting (multi bandwidth).

The communication device may select the first bandwidth or the second bandwidth based on a type of terminals belonging to the network or a distance to the terminals.

The selection of the bandwidth may be performed based on at least one of the number of terminals using the first bandwidth, the distance to the communication device, and the coverage of the communication device.

The terminals belonging to the network may demodulate both the basic frame generated based on the first bandwidth and the basic frame generated based on the second bandwidth.

The duplication mode frame includes a base frame and a duplication frame that is out of phase with the base frame, and the base frame includes a short training field (STF), a long training field (LTF), and repetition. It may include a coded signal field (repetition coded SIG field).

The transmitting of the duplication mode frame may include transmitting the base frame through a first band and simultaneously transmitting the duplication frame through a second band.

The multiple bandwidths may include 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz.

The frame structure of the first bandwidth has a form in which information on multiple bandwidths is omitted, and a basic frame generated based on the first bandwidth may include information on the multiple bandwidths in a signal field or a service field.

According to embodiments of the present invention, a frame structure of a duplication mode of 2 MHz unit and duplication mode of 1 MHz unit may be used for control frame transmission in a wide area wireless LAN system supporting multiple bandwidths.

According to embodiments of the present invention, it is possible to allocate a dynamic bandwidth, and to configure a wide area WLAN system supporting wider coverage.

The duplication mode frame structure and the duplication mode frame transmission method according to embodiments of the present invention can be applied to a wide area wireless LAN system supporting wider coverage.

FIG. 1 is a diagram for describing multiple bandwidths of a wide area wireless LAN system.

2 is a diagram illustrating a basic bandwidth selection method according to an embodiment of the present invention.

3 is a diagram illustrating a frame structure of a first bandwidth of multiple bandwidths of a wide area wireless LAN system.

FIG. 4 is a diagram illustrating a frame structure of a second bandwidth among multiple bandwidths of a wide area wireless LAN system.

5A and 5B illustrate a configuration example of a duplication mode frame according to an embodiment.

6A-6C illustrate a duplication mode frame structure of an NDP type short CTS message.

7A and 7B are diagrams for describing an example of a configuration of a duplication mode frame according to another embodiment.

8 illustrates a configuration of a communication device of a wide area wireless LAN system according to an embodiment.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

A wide area WLAN system, for example, a WLAN system defined in the IEEE 802.11ah standard, may support multiple bandwidths. The multiple bandwidths can include a first bandwidth having the lowest signal-to-noise ratio and a second bandwidth that is twice the first bandwidth. In this case, the value of the first bandwidth may be 1 MHz.

Referring to FIG. 1, the multi-bandwidth may include a 1 MHz bandwidth 110, a 2 MHz bandwidth 120, a 4 MHz bandwidth 130, an 8 MHz bandwidth 140, and a 16 MHz bandwidth 150. The frequency band of the wide area wireless LAN system may be 1 GHz or less.

Thus, "multiple bandwidths include 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz."

Accordingly, the lower frequency limit value 161 of FIG. 1 may be a value between 700 and 920 [MHz], and the upper frequency limit value 163 may be a value between 750 and 930 [MHz].

As shown in FIG. 1, the 1 MHz bandwidth 110 may be allocated over an entire channel, and the

remaining bandwidths

120, 130, 140, and 150 may be allocated only to a partial interval of the entire channel.

For example, the 16 MHz bandwidth 150 may be allocated between the frequency upper limit value 163 at 165 of FIG. 1. Referring to FIG. 1, 8 MHz is allocated to the 2 MHz bandwidth 120, 4 channels are allocated to the 4

MHz bandwidth

130, and 2 channels are allocated to the 8 MHz bandwidth 140. However, the channel assignment shown in FIG. 1 is exemplary, and the number and frequency bands of the channels can be configured in various ways.

In the present specification, a transmission mode having a bandwidth value of 1 MHz (110) will be referred to as a 1 MHz mode, and a transmission mode having a bandwidth value of 2 MHz (120) will be referred to as a 2 MHz mode.

The 1 MHz mode is a transmission mode having 32 subcarriers while maintaining an orthogonal frequency division multiplexing (OFDM) symbol structure. At this time, since the 1MHz mode uses a frequency domain repetition transmission scheme, the transmission rate among the bandwidths is the lowest. However, the 1MHz mode has a low signal-to-noise ratio and can transmit signals up to the longest distance.

Meanwhile, in a wide area wireless LAN system using a frequency band of less than 1 GHz, terminals should be able to receive both a signal transmitted in a 1 MHz mode and a signal transmitted in a 2 MHz mode.

In case of a WLAN technology using a 5 GHz band, a frame structure for dynamic bandwidth allocation is disclosed. However, the packet structure of the WLAN technology using the 5GHz band is difficult to be applied to a wide area WLAN system using a frequency band of less than 1GHz. Therefore, a frame structure suitable for a frequency band of less than 1 GHz is required.

Referring to FIG. 2, the communication device 210 may be an access point (AP) or a base station. STA 1 220 and STA 2 230 exist within coverage 211 of communication device 210. In this case, STA 1 220 and STA 2 230 are terminals capable of receiving and demodulating both a signal transmitted in a 1 MHz mode and a signal transmitted in a 2 MHz mode, respectively.

When the communication device 210 transmits a signal using the 2 MHz mode, the STA 1 220 may receive the signal but the STA 2 230 may not receive the signal.

On the other hand, the 1MHz mode has the longest transmission distance of the signal. Therefore, when the communication device 210 transmits a signal using the 1 MHz mode, the STA 2 230 may also receive the signal.

Therefore, a duplication mode using 2 MHz as a basic bandwidth is required and a duplication mode using 1 MHz as a basic bandwidth.

In this case, the frame transmitted in the duplication mode may be referred to as a duplication mode frame. The duplication mode frame will be described in detail with reference to FIGS. 3 to 7.

In this case, the first bandwidth may be 1 MHz, and the second bandwidth may be 2 MHz.

Referring to FIG. 3, a 1 MHz mode frame includes a short training field (STF) 310, a long training field (LTF) 320, and a repetition coded SIG field ( 330).

Meanwhile, the SIG field 410 of the 2 MHz mode frame contains a total of 48 bits of information including 9 bits of length information, 4 bits of Modulation and Coding Scheme (MCS) information, and 2 bits of bandwidth information. The SIG field 330 of the 1 MHz mode frame includes 36 bits of information in which the information on the bandwidth is omitted.

There may be a variety of ways of configuring a duplication mode frame using a 1 MHz mode frame and a 2 MHz mode frame.

First, a method of configuring a duplication mode frame based on a 2 MHz mode frame will be described with reference to FIGS. 5A and 5B to 6A-6C. Next, a method of configuring a duplication mode frame based on the 1 MHz mode frame will be described with reference to FIG. 7.

5A shows a 4 MHz duplication mode frame.

In this case, the 4MHz duplication mode frame may include a base frame 510 and a duplication frame 520 that is 90 degrees out of phase with the base frame 510. Referring to FIG. 5A, in the duplication mode frame transmission, the same frame is shifted by 90 ° with respect to the DC tone and transmitted through two bands.

That is, the process of transmitting the duplication mode frame may include transmitting the base frame through the first band and simultaneously transmitting the duplication frame through the second band.

Accordingly, the receiving end receiving the duplication mode frame may perform demodulation even when receiving only a frame received in one of the first band and the second band.

As shown in FIG. 5A, the basic frame 510 may have the same structure as the 2 MHz mode frame shown in FIG. 4. Accordingly, the basic frame 510 may include a short training field (STF), a long training field (LTF), and a SIG field.

5B shows an 8 MHz duplication mode frame.

The 8 MHz duplication mode frame may include a base frame 510 and three duplication frames 530 that are 180 degrees out of phase with the base frame 510.

Four frames included in the 8 MHz duplication mode frame may be simultaneously transmitted through four different bands.

Accordingly, the receiving end receiving the duplication mode frame may perform demodulation or detection even when receiving only one frame among the frames transmitted through four different bands.

Although not shown in FIGS. 5A and 5B, the 16 MHz duplication mode frame has a structure in which an 8 MHz duplication mode frame is repeated twice on the frequency axis.

The duplication mode frame structure shown in FIGS. 5A and 5B may be used for a request to send (RTS) and a "null data packet (NDP) type short clear to send (CTS) message without data portion".

Figure 6a is a frame structure of a 2MHz mode NDP type short CTS message.

6b illustrates a frame structure of a 4 MHz duplicate NDP type short CTS message configured based on a 2 MHz bandwidth.

6C illustrates a frame structure of an 8 MHz duplicate NDP type short CTS message configured based on a 2 MHz bandwidth.

In the example illustrated in FIGS. 6A-6C, the information included in the SIG may vary according to the information included in the NDP type short CTS message. For example, the information included in the SIG may be configured with a total of 48 bits, including 2 bits for indicating the bandwidth used.

Control information such as RTS and CTS may be transmitted and received using a duplication mode frame based on a 2 MHz bandwidth. At this time, the terminal that does not receive the 2MHz mode signal, such as STA2 (230) of Figure 2, but can receive the 1MHz mode signal may not be able to receive the communication control information.

Therefore, it is necessary to configure the duplication mode frame using the frame structure used in the 1MHz mode.

7A shows a 2 MHz duplication mode frame.

In this case, the 2MHz duplication mode frame may include a base frame 710 and a duplication frame 720 that is 90 degrees out of phase with the base frame 710. Referring to FIG. 7A, in the duplication mode frame transmission, the same frame is shifted by 90 ° with respect to the DC tone and transmitted through two bands.

That is, the process of transmitting the duplication mode frame may include transmitting the base frame through the third band and simultaneously transmitting the duplication frame through the fourth band.

Accordingly, the receiving end receiving the duplication mode frame may perform demodulation even when receiving only a frame received in any one of the third band and the fourth band.

As shown in FIG. 7A, the basic frame 710 may have the same structure as the 1 MHz mode frame shown in FIG. 3. Accordingly, the basic frame 710 may include a short training field (STF), a long training field (LTF), and a SIG field.

As described in FIG. 3, the SIG field of the 1 MHz mode frame may have a structure in which information about bandwidth is omitted.

When configuring a duplication mode frame based on 1 MHz bandwidth, it is necessary to insert information for defining the bandwidth. For example, some bits of 4 bits defined as reserved bits of the SIG may be used to insert information about bandwidth. In this case, the information on the bandwidth may be information on which band of the frequency axis is used in the example illustrated in FIG. 7A. In addition, some of the lower bits of the scrambler sheet in the SERVICE field may be used to define bandwidth information.

Three bits may be required to define the bandwidth divided into 1, 2, 4, 8, and 16 [MHz].

Therefore, the frame structure of the first bandwidth is a form in which information on multiple bandwidths is omitted, and a basic frame generated based on the first bandwidth may include information on the multiple bandwidths in a signal field or a service field.

7B shows a 4 MHz duplication mode frame.

The 4MHz duplication mode frame may include a base frame 710 and three duplication frames 730 that are 180 degrees out of phase with the base frame 710.

As in the example illustrated in FIGS. 6A-6C, an NDP type short CTS message may be generated based on a 1 MHz bandwidth. In this case, the NDP type short CTS message has no field after "LTF2" in FIG. 7.

Referring to FIG. 8, the communication device 800 includes a basic frame generator 810, a duplication mode frame configuration unit 820, and a frame transmitter 830. In addition, the communication device 800 may further include a controller 840.

The base frame generator 810 may generate a base frame based on one of a first bandwidth having the lowest signal-to-noise ratio among the preset bandwidths and a second bandwidth that is twice the first bandwidth. .

The basic frame generator 810 may select the first bandwidth or the second bandwidth based on a type of terminals belonging to a network or a distance to the terminals. For example, the basic frame generator 810 may select a bandwidth based on at least one of the number of terminals using the first bandwidth, the distance to the communication device, and the coverage of the communication device.

The duplication mode frame configuration unit 820 may configure a duplication mode frame based on the basic frame.

The frame transmitter 830 may transmit the duplication mode frame to a network that supports multi-bandwidth through a plurality of bands.

The frame transmitter 830 may transmit the basic frame through the first band and simultaneously transmit the duplication frame through the second band.

The communication device 800 may select the first bandwidth or the second bandwidth based on a type of terminals belonging to a network or a distance to the terminals. In this case, the types of terminals may be classified into whether the terminal can receive only a 1 MHz mode signal, or a terminal capable of receiving only a 2 MHz mode signal.

The controller 840 may include at least one processor for controlling the overall operation of the communication device 800.

The controller 840 may collect distance information to the terminals through signaling with the terminals in the network, or may receive information about the distance to the terminals from the higher level device. In addition, the controller 840 may determine whether to transmit a duplication mode frame based on a 1 MHz bandwidth or a duplication mode frame based on a 2 MHz bandwidth.

For example, the controller 840 is based on the collected information, when there are more than a predetermined number of terminals using a 1MHz bandwidth or a plurality of terminals existing at a distance farther than a predetermined distance, the controller 840 duplexes the 1MHz bandwidth as a basic unit. The communication device 800 may be controlled to transmit the application mode frame.

Alternatively, when the cell coverage is smaller than the preset size, the controller 840 may control the communication device 800 to transmit a duplication mode frame based on a 2 MHz bandwidth. In this case, when the duplication mode frame is transmitted based on a 2 MHz bandwidth, the air time of the control frame may be reduced and the overall efficiency of the network may be increased.

The method according to the embodiment may be embodied in the form of program instructions that can be executed by various computer means and recorded in a computer readable medium. The computer readable medium may include program instructions, data files, data structures, etc. alone or in combination. The program instructions recorded on the media may be those specially designed and constructed for the purposes of the embodiments, or they may be of the kind well-known and available to those having skill in the computer software arts. Examples of computer readable recording media include magnetic media such as hard disks, floppy disks and magnetic tape, optical media such as CD-ROMs, DVDs, and magnetic disks such as floppy disks. Magneto-optical media, and hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include only machine code, such as that produced by a compiler.

It also contains high-level language code that can be executed by a computer using an interpreter or the like. The hardware device described above may be configured to operate as one or more software modules to perform the operations of the embodiments, and vice versa.

Although the embodiments have been described by the limited embodiments and the drawings as described above, various modifications and variations are possible to those skilled in the art from the above description. For example, the described techniques may be performed in a different order than the described method, and / or components of the described systems, structures, devices, circuits, etc. may be combined or combined in a different form than the described method, or other components. Or even if replaced or substituted by equivalents, an appropriate result can be achieved.

Therefore, other implementations, other embodiments, and equivalents to the claims are within the scope of the claims that follow.

Claims

A communication device of a network that supports multi-bandwidth may be configured based on one of a first bandwidth having a lowest signal-to-noise ratio among preset bandwidths and a second bandwidth that is twice the first bandwidth. Generating a basic frame;

Constructing a duplication mode frame based on the basic frame; And

Transmitting the duplication mode frame over a plurality of bands

Communication method of a wide area wireless LAN system comprising a.
The method of claim 1,

The communication device selects the first bandwidth or the second bandwidth based on a type of terminals belonging to the network or a distance to the terminals.

Communication method of wide area wireless LAN system.
The method of claim 2,

The selection of the bandwidth is performed based on at least one of the number of terminals using the first bandwidth, the distance to the communication device, and the coverage of the communication device.

Communication method of wide area wireless LAN system.
The method of claim 1,

The terminals belonging to the network may demodulate both the base frame generated based on the first bandwidth and the base frame generated based on the second bandwidth.

Communication method of wide area wireless LAN system.
The method of claim 1,

The duplication mode frame includes a base frame and a duplication frame that is out of phase with the base frame, and the base frame includes a short training field (STF), a long training field (LTF), and repetition. Including a coded SIG field

Communication method of wide area wireless LAN system.
The method of claim 5,

Transmitting the duplication mode frame,

Transmitting the basic frame on a first band and simultaneously transmitting the duplication frame on a second band.

Communication method of wide area wireless LAN system.
The method of claim 1,

The multi-bandwidth includes 1 MHz, 2 MHz, 4 MHz, 8 MHz and 16 MHz

Communication method of wide area wireless LAN system.
The method of claim 1,

The frame structure of the first bandwidth is a form in which information on multiple bandwidths is omitted, and a basic frame generated based on the first bandwidth includes information on the multiple bandwidths in a signal field or a service field.

Communication method of wide area wireless LAN system.
A base frame generator configured to generate a base frame based on one of a first bandwidth having a lowest signal-to-noise ratio and a second bandwidth that is twice the first bandwidth;

A duplication mode frame configuration unit configured to configure a duplication mode frame based on the basic frame; And

Frame transmission unit for transmitting the duplication mode frame to a network supporting a multi-bandwidth through a plurality of bands (band)

Communication device of a wide area wireless LAN system comprising a.
The method of claim 9,

The basic frame generation unit,

Selecting the first bandwidth or the second bandwidth based on a type of terminals belonging to the network or a distance to the terminals;

Communication device of wide area wireless LAN system.
The method of claim 10,

The basic frame generation unit,

Selecting a bandwidth based on at least one of the number of terminals using the first bandwidth, the distance to the communication device and the coverage of the communication device

Communication device of wide area wireless LAN system.
The method of claim 9,

The terminals belonging to the network may demodulate both the base frame generated based on the first bandwidth and the base frame generated based on the second bandwidth.

Communication device of wide area wireless LAN system.
The method of claim 9,

The duplication mode frame includes a base frame and a duplication frame that is out of phase with the base frame, and the base frame includes a short training field (STF), a long training field (LTF), and repetition. Including a coded SIG field

Communication device of wide area wireless LAN system.
The method of claim 13,

The frame transmission unit,

Transmitting the basic frame through a first band and simultaneously transmitting the duplication frame through a second band

Communication device of wide area wireless LAN system.
The method of claim 9,

The multi-bandwidth includes 1 MHz, 2 MHz, 4 MHz, 8 MHz and 16 MHz

Communication device of wide area wireless LAN system.
The method of claim 9,

The frame structure of the first bandwidth is a form in which information on multiple bandwidths is omitted, and the basic frame generator inserts the information on the multiple bandwidths into a signal field or a service field of a basic frame generated based on the first bandwidth. doing

Communication device of wide area wireless LAN system.