KR101000932B1 - Method for communication between devices supporting multiple communication modes in WiFi and apparatus for same - Google Patents

Abstract

In a wireless personal area network (WPAN), a device supporting a plurality of PHY communication modes determines a timing for changing a PHY communication mode by referring to a beacon frame to communicate with devices in various PHY communication modes, and at the determined timing, the PHY communication mode. A method of operating a WPAN device is disclosed that delivers information indicating a to a PHY layer as a primitive parameter.

Description

Method and apparatus for allowing a device which supports multiple PHY communication modes to communicate with other devices in Wireless Personal Area Network}

The present invention relates to a method in which a device communicates in a wireless personal area network (WPAN).

A wireless personal area network (WPAN) is a wireless network in which devices existing within a short distance perform data communication at low power. In WPAN, devices belonging to a piconet share a channel using a time division multiple access (TDMA) scheme. That is, devices to perform data communication monopolize a channel for a time allocated to a device called Piconet Coordinator (PNC) and perform data communication.

Recently, as a technique for transmitting a large amount of data at high speed in a frequency band of 60 GHz using a millimeter wave having a short wavelength of about 1 to 10 mm and a strong straightness (or directivity) in a WPAN, SC (Single Carrier), OFDM ( Various PHY communication modes such as Orthogonal Frequency Division Multiplexing (OOK) and On-Off-Keying (OOK) have been made available in WPAN.

Since devices having different PHY communication modes cannot communicate with each other, a device supporting a plurality of PHY communication modes must switch PHY communication mode according to circumstances. However, in the past, it is assumed that all devices belonging to the piconet use one PHY communication mode, and thus, an internal process that a device supporting multiple PHY communication modes must perform to communicate with other devices in the piconet is yet to be performed. Not specifically defined.

The present invention provides an internal process that a device supporting multiple PHY communication modes in WPAN performs to communicate with other devices having various PHY communication modes in the piconet.

An embodiment of the present invention for achieving this object, the method for operating a WPAN device, comprising: determining a timing to change the PHY communication mode of the device from a first communication mode to a second communication mode; And transferring information indicating the second communication mode at a determined timing from a higher layer of the device to a PHY layer as a parameter of a predetermined primitive.

The device operates as a device in the parent piconet and as a PNC in the child piconet of the parent piconet, one of the two PHY communication modes is used to communicate with the PNC of the parent piconet, and the other belongs to the child piconet. It can be used for communication with the field.

The one PHY communication mode is a PHY communication mode commonly supported by PNCs of all child piconets belonging to the parent piconet, and the other PHY communication mode is SC (Single Carrier), OOK (On-Off Keying) and OFDM. It is preferably one of (Orthogonal Frequency Division Multiplexing).

The timing is preferably determined based on a beacon frame received from the PNC of the parent piconet.

The primitive may be PHY-TX-START.request or PHY-RX-START.request.

The primitive preferably further includes information on each of the plurality of subframes included in the MAC frame body of one data frame as a parameter of the number of subframes.

In addition, an embodiment of the present invention provides a recording medium that records a computer program for executing a method of operating the WPAN device.

According to another aspect of the present invention, there is provided an apparatus for controlling a WPAN device, comprising: a determining unit configured to determine a timing for changing a PHY communication mode of the device from a first communication mode to a second communication mode; And a primitive processing unit for transferring the information indicating the second communication mode to the PHY layer of the device at the determined timing as a parameter of a predetermined primitive.

The device operates as a device in the parent piconet and as a PNC in the child piconet of the parent piconet, one of the two PHY communication modes is used to communicate with the PNC of the parent piconet, and the other belongs to the child piconet. It can be used for communication with the field.

The one PHY communication mode is a PHY communication mode commonly supported by PNCs of all child piconets belonging to the parent piconet, and the other PHY communication mode is SC (Single Carrier), OOK (On-Off Keying) and OFDM. It is preferably one of (Orthogonal Frequency Division Multiplexing).

Preferably, the determination unit determines the timing based on a beacon frame received from the PNC of the parent piconet.

 The primitive may be PHY-TX-START.request or PHY-RX-START.request.

The primitive preferably further includes information on each of the plurality of subframes included in the MAC frame body of one data frame as a parameter of the number of subframes.

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

1A and 1B are diagrams for describing a method of communicating devices in a piconet according to an embodiment of the present invention.

The six devices 101-106 shown in FIG. 1A form a parent piconet 110, and the parent piconet 110 is configured to include two child piconets 110, 120. Include.

The six devices are classified into single carrier (SC), on-off keying (OOK), orthogonal frequency division multiplexing (OFDM), etc. according to a physical layer protocol, that is, a PHY communication mode. Hereinafter, a device using an SC-type PHY communication mode is referred to as an SC device, a device using a OOK-type PHY communication mode as an OOK device, and a device using an OFDM type PHY communication mode as an OFDM device.

In FIG. 1A, since devices having different PHY communication modes cannot communicate with each other, the device 101 using the SC type PHY communication mode may perform data communication only with the SC device 102. However, since other devices that cannot communicate with the device 101 currently operating as the PNC of the parent piconet 100 cannot be assigned a channel time for communication, the same PHY is used in the WPAN according to an embodiment of the present invention. Devices using the communication mode configure the child piconet, and the devices 103 and 105 supporting the PNC function in each child piconet perform the PNC role in the child piconet. Accordingly, in the WPAN of FIG. 1A, the device 101 operates as the PNC of the parent piconet 110, the device 103 operates as the PNC of the child piconet 110, and the device 105 operates as the PNC of the child piconet 120. Operate with PNC.

In general, since the devices in the WPAN are allocated channel time from the PNC through signaling, signaling between at least the PNC 101 of the parent piconet 100 and the PNCs 103 and 105 of the child piconets 110 and 120. Should be possible. Here, signaling refers to a process of transmitting and receiving a message for establishing / controlling a communication environment in a piconet, as opposed to data communication, and includes a beacon, a probe request / response, and a coupling request / response. Association request / response and the like are transmitted and received between the PNC and the devices through signaling.

Accordingly, devices 101, 102, and 103 that support the PNC function in the WPAN according to an embodiment of the present invention must support at least one common PHY communication mode. Hereinafter, the PHY communication mode uses the common data. This will be referred to as a common rate mode. For example, the common data rate mode may be designated as a PHY communication mode using a 50 Mbps data rate of the SC scheme.

The PNCs 103 and 105 of the child piconets 110 and 120 are allocated channel time from the PNC 101 of the parent piconet 100 through signaling according to a common data rate mode, and the child piconets 110 and 120 are allocated. The channel times allocated to the PNCs 103 and 105 of the C1, respectively, are equal to the super frame length of the corresponding child piconet. In the child piconet, both signaling and data communication are performed according to a common PHY communication scheme of devices belonging to the piconet. That is, in FIG. 1A, signaling and data communication are performed according to the OOK scheme in the child piconet 110 and the OFDM scheme in the child piconet 120.

FIG. 1B illustrates an embodiment of the super frame structure of the parent piconet 100 shown in FIG. 1A. As shown in FIG. 1B, the PNC 101 of the parent piconet 100 broadcasts a beacon frame according to the common data rate mode to the parent piconet 100. Assuming that the common data rate mode is a basic data rate according to the SC scheme, this beacon frame can be interpreted only by the SC device 102 and devices 103 and 105 that support the PNC function.

Accordingly, in the contention access period (CAP), the SC device 102, the OFDM PNC / DEV 105, and the OOK PNC / DEV 103 each have a channel time corresponding to CTA 1, CTA 2, and CTA 3, respectively. Assigned. For reference, "OFDM PNC / DEV" means a device using an OFDM scheme and a device supporting a PNC function. Accordingly, the OFDM PNC / DEV 105 uses the PHY communication mode of the OFDM scheme, but also supports the common data rate mode because it supports the PNC function. Similarly, the OOK PNC / DEV 103 also supports both the OOK PHY communication mode and the common data rate mode.

As described above, since the channel time allocated to the PNC of the child piconet corresponds to the super frame length in the child piconet, CTA 2 becomes the super frame in the child piconet 120, and CTA 3 is the child piconet 110. Becomes the super frame of the. Signaling and data communication between devices of the child piconet 110 are performed according to the OOK scheme, and signaling and data communication between devices of the child piconet 120 are performed according to the OFDM scheme.

2 is a diagram illustrating the structure of a data frame according to an embodiment of the present invention.

As shown in FIG. 2, a data frame according to an embodiment of the present invention includes a preamble 201, a PHY header 202, a MAC header 204, an HCS1 205, subheaders 206, and an HCS2 ( 207, subframes 208.

The PHY header 202 may include a subheader flag (not shown) indicating whether or not the subheaders 206 are included in the data frame.

The HCS1 205 is a field in which a header check sequence (HCS), which is a CRC code for detecting an error of the preamble 201, the PHY header 202, and the MAC header 204, is recorded, and the HCS2 207 is a subheader. A field in which an HCS, which is a CRC code for detecting an error of 206, is recorded.

On the other hand, each of the subheaders 211 constituting the subheaders 206 includes information indicating which Modulation and Coding Scheme (MCS) has been applied to the subframe, information indicating whether the FCS is included in the subframe, When the subframe is one of fragments of the MAC Service Data Unit (MSDU), information indicating the order of the corresponding subframe within the fragments may be included.

That is, a data frame according to an embodiment of the present invention may include a plurality of subframes in one MAC frame body, and these subframes are generated from at least one MSDU.

Meanwhile, although 40 bits are allocated to each subframe in the embodiment shown in FIG.

3 is a diagram for describing a method of changing a PHY communication mode by a WPAN device supporting a plurality of PHY communication modes according to an embodiment of the present invention.

As shown in FIG. 3, in the WPAN device, the MAC layer and the PHY layer include management entities called MLME and PLME, respectively, and every device has a layer independent device management entity (Device) for accurate MAC operation. Management Entity (DME)).

The various entities shown in FIG. 3 interact by exchanging commands called primitives via a Service Access Point (SAP).

For example, PHY-TX-START.request is a primitive used when the MAC layer requests the PHY layer to start sending MAC Protocol Data Units (MPDUs). PHY-TX-START.request includes various parameters such as TXDataRate, TXLengh, TXPowerLevel, TXMACHead, and TXAntSelect.

TXDataRate represents the data rate used for transmission of the frame. TXLengh indicates the length of the MAC frame to be transmitted. TXPowerLevel indicates the transmit power to be used for transmission of the frame. TXMACHead is a MAC header of a frame to be transmitted. TXAntSelect specifies an antenna to be used for transmission of data.

On the other hand, PHY-RX-START.request is a primitive used when the MAC layer requests the PHY layer to activate a receiver to start receiving a frame. In PHY-RX-START.request, the RXAntSelect parameter is used to specify the antenna to be used for receiving data.

As another example, PHY-RX-START.indication is a primitive used to inform the MAC layer that the PHY layer has received a valid PHY and MAC header. The PHY-RX-START.indication primitive includes parameters such as RXDataRate, RXLength, RXMACHead, and RSSI.

RXDataRate represents the data rate of the received frame. RXLength represents the length of the received frame. RXMACHead is the MAC header of the received frame. RSSI indicates the power level of the received signal.

A more detailed description of the various primitives and parameters used in the WPAN is described in the IEEE 802.15.3 standard, and will be omitted here.

As described above, since the existing WPAN device is assumed to use only one PHY communication mode, primitives or parameters associated with the PHY transmission mode are not defined. Accordingly, the present invention relates to a PHY communication mode as a parameter of a primitive exchanged between a MAC layer and a PHY layer so that a device supporting a plurality of PHY communication modes can change the PHY transmission mode while maintaining compatibility with the existing IEEE 802.15.3 standard. Communicate information

That is, as shown in FIG. 3, the MAC layer of the WPAN device according to the present invention delivers PHY communication mode information as a parameter of a primitive to the PHY layer, and the PHY layer also sends PHY communication mode information as a parameter of the primitive to the MAC layer. To pass.

For example, the MAC layer sends PHY communication mode information as a parameter of PHY-TX-START.request and requests the PHY layer to transmit a frame in the corresponding PHY communication mode. In addition, the MAC layer transmits PHY communication mode information as a parameter of PHY-RX-START.request and requests the PHY layer to receive a frame.

Meanwhile, the PHY communication mode information may be a parameter of PHY-RX-START.indication. That is, the PHY layer of the device may transmit PHY communication mode information indicating which PHY communication mode was used to receive the frame as a parameter of the PHY-RX-START.indication to the MAC layer.

Meanwhile, when a data frame including a plurality of subframes is received, the PHY layer may deliver MAC subheaders as parameters of PHY-RX-START.indication to the MAC layer. In this case, since the number of MAC subheaders is the same as the number of subframes, eventually as many parameters as the number of subframes will be required.

4 is a flowchart illustrating a process of operating a WPAN device according to an embodiment of the present invention.

In step 410, the device analyzes the beacon frame transmitted from the PNC.

In step 420, the device refers to the beacon frame to determine the timing to change the PHY communication mode.

In step 430, the MAC layer of the device delivers information indicating the PHY communication mode as a primitive parameter to the PHY layer at the determined timing.

For example, in FIG. 1, the OFDM PNC / DEV 105 refers to a beacon frame received from the PNC 101 of the parent piconet 100 and that CTA 2 is assigned to a child piconet 120 that operates as a PNC. Get to know. Accordingly, the OFDM PNC / DEV 105 determines the timing at which the CTA 2 starts to change the PHY communication mode from the common data rate mode to the OFDM mode, and communicates using the OFDM device 106 and the OFDM mode during CTA 2. do.

5 is a diagram illustrating the structure of a WPAN device according to an embodiment of the present invention.

As shown in FIG. 5, a device 500 according to an embodiment of the present invention includes a MAC layer module 510 and a PHY layer module 520. The MAC layer module 510 is a device 500 according to an embodiment of the present invention, that is, a device that supports a plurality of PHY transmission modes so that devices having various PHY transmission modes can communicate in a piconet where coexistence. 500). The PHY layer module 520 performs processes that are processed at the PHY layer of the device 500.

The MAC layer module 510 includes a beacon analyzer 511, a determiner 512, and a primitive processor 513.

The beacon analyzer 511 analyzes the beacon received from the PNC of the WPAN 550.

The determiner 512 determines a timing to change the PHY communication mode based on the analysis result of the beacon analyzer 511.

For example, when the device 500 operates as a device in a parent piconet and as a PNC in a child piconet in which an OFDM scheme is used, the device 500 communicates in a common data rate mode when communicating with a PNC of a parent piconet. During the channel time, the device communicates with the devices of the child piconet by the OFDM scheme. Therefore, the channel time allocated to itself, i.e., the start time of the super frame of the OFDM child piconet, is determined as the timing to change the PHY transmission mode.

The primitive processing unit 513 transfers information indicating the PHY communication mode to be changed at the timing determined by the determination unit 512 to the PHY layer module 520 as a parameter of the primitive.

As described above, the primitive at this time may be PHY-TX-START.request or PHY-RX-START.request. In addition, the information indicating the PHY communication mode may indicate one of Single Carrier (SC), On-Off Keying (OOK), and Orthogonal Frequency Division Multiplexing (OFDM).

In the above embodiments, the case in which the device supports two PHY communication modes has been described, but it will be apparent to those skilled in the art that the present invention can be applied to the case in which three or more PHY communication modes are supported.

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 an illustrative rather than a restrictive sense. 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.

1A and 1B are diagrams for describing a method of communicating devices in a piconet according to an embodiment of the present invention;

2 is a diagram showing the structure of a data frame according to an embodiment of the present invention;

3 is a diagram for describing a method of changing a PHY communication mode by a WPAN device supporting a plurality of PHY communication modes according to an embodiment of the present invention;

4 is a flowchart illustrating a process of operating a WPAN device according to an embodiment of the present invention;

5 is a diagram illustrating the structure of a WPAN device according to an embodiment of the present invention.

Claims (13)

In the manner in which the WPAN device operates, Determining a timing to change the PHY communication mode of the device from a first communication mode to a second communication mode; And Passing information indicating the second communication mode at a predetermined timing as a parameter of a predetermined primitive from an upper layer of the device to a PHY layer. The method of claim 1, The device operates as a device in a parent piconet and as a PNC in a child piconet of the parent piconet, One of the first communication mode and the second communication mode is used to communicate with the PNC of the parent piconet, and the other is used for communication with devices belonging to the child piconet. 3. The method of claim 2, The one PHY communication mode is a PHY communication mode commonly supported by PNCs of all child piconets belonging to the parent piconet, and the other PHY communication mode is SC (Single Carrier), OOK (On-Off Keying) and OFDM. (Orthogonal Frequency Division Multiplexing). 3. The method of claim 2, And the timing is determined based on a beacon frame received from the PNC of the parent piconet. The method of claim 1, And the primitive is PHY-TX-START.request or PHY-RX-START.request. The method of claim 1, The primitive further includes information on each of the plurality of subframes included in the MAC frame body of one data frame as a parameter of the number of subframes. An apparatus for controlling a WPAN device, A determination unit to determine a timing to change the PHY communication mode of the device from a first communication mode to a second communication mode; And And a primitive processing unit for transferring the information indicating the second communication mode to the PHY layer of the device at the determined timing as a parameter of a predetermined primitive. The method of claim 7, wherein The device operates as a device in a parent piconet and as a PNC in a child piconet of the parent piconet, Wherein one of the first communication mode and the second communication mode is used to communicate with a PNC of the parent piconet, and the other is used for communication with devices belonging to the child piconet. The method of claim 8, The one PHY communication mode is a PHY communication mode commonly supported by PNCs of all child piconets belonging to the parent piconet, and the other PHY communication mode is SC (Single Carrier), OOK (On-Off Keying) and OFDM. (Orthogonal Frequency Division Multiplexing). The method of claim 8, And the determining unit determines the timing based on a beacon frame received from the PNC of the parent piconet. The method of claim 7, wherein And the primitive is PHY-TX-START.request or PHY-RX-START.request. The method of claim 7, wherein The primitive further includes information on each of the plurality of subframes included in the MAC frame body of one data frame as a parameter of the number of subframes. A recording medium on which a computer program for executing the method according to any one of claims 1 to 6 is recorded.

Images