KR20160047405A - Wireless communication method and wireless communication terminal for packet auto detection - Google Patents

Abstract

The present invention relates to a wireless communication method which suggests a packet preamble structure for efficient automatic detection of a legacy packet and a non-legacy packet, and and a wireless communication terminal using the wireless communication method. The present invention provides a wireless communication terminal which comprises: a transmission and reception unit which transmits and receives a wireless signal; and a processor which controls operation of the terminal. The processor receives a wireless packet via the transmission and reception unit, wherein the wireless packet includes a legacy preamble for a legacy terminal and a non-legacy preamble for a non-legacy terminal, and determines whether the corresponding wireless packet is a non-legacy packet based on a modulation method used for the non-legacy preamble of the received wireless packet. The present invention also provides a wireless communication method.

Description

TECHNICAL FIELD [0001] The present invention relates to a wireless communication method for automatically detecting a packet,

The present invention relates to a wireless communication method that proposes a packet preamble structure for efficient automatic detection between a legacy packet and a non-legacy packet, and a wireless communication terminal using the same.

Recently, as the spread of mobile devices has expanded, wireless LAN technology capable of providing fast wireless Internet service has attracted much attention. Wireless LAN technology is a technology that enables wireless devices such as smart phones, smart pads, laptop computers, portable multimedia players, and embedded devices to wirelessly connect to the Internet at home, to be.

IEEE (Institute of Electrical and Electronics Engineers) Since 802.11 supports the initial wireless LAN technology using 2.4 GHz frequency, various technology standards are being put into practical use or under development. First, IEEE 802.11b supports a communication speed of up to 11 Mbps while using a frequency of 2.4 GHz band. IEEE 802.11a, which has been commercialized since IEEE 802.11b, uses the frequency of the 5GHz band instead of the 2.4GHz band, thereby reducing the interference effect compared to the frequency of the highly congested 2.4GHz band. Using OFDM technology, To 54Mbps. However, IEEE 802.11a has a short communication distance compared to IEEE 802.11b. IEEE 802.11g, like IEEE 802.11b, uses a frequency of 2.4GHz band to achieve a communication speed of up to 54Mbps and has received considerable attention because it meets backward compatibility. It is in the lead.

IEEE 802.11n is a technical standard established to overcome the limitation of the communication speed which is pointed out as a weak point in the wireless LAN. IEEE 802.11n aims to increase the speed and reliability of the network and to extend the operating distance of the wireless network. More specifically, IEEE 802.11n supports high throughput (HT) with data rates of up to 540 Mbps or higher, and uses multiple antennas at both ends of the transmitter and receiver to minimize transmission errors and optimize data rates. It is based on Multiple Inputs and Multiple Outputs (MIMO) technology. In addition, the specification may use a coding scheme that transfers multiple duplicate copies to increase data reliability.

As the spread of the wireless LAN is activated and the applications using it are diversified, there is a need for a new wireless LAN system to support a very high throughput (VHT) higher than the data processing speed supported by IEEE 802.11n . IEEE 802.11ac supports wide bandwidth (80MHz ~ 160MHz) at 5GHz frequency. The IEEE 802.11ac standard is defined only in the 5GHz band, but for backward compatibility with existing 2.4GHz band products, early 11ac chipsets will also support operation in the 2.4GHz band. Theoretically, according to this standard, the wireless LAN speed of multiple stations is at least 1Gbps and the maximum single link speed is at least 500Mbps. This is accomplished by extending the concept of wireless interfaces accepted in 802.11n, including wider radio frequency bandwidth (up to 160 MHz), more MIMO spatial streams (up to 8), multiuser MIMO, and high density modulation (up to 256 QAM). In addition, IEEE 802.11ad is a method of transmitting data using a 60 GHz band instead of the existing 2.4 GHz / 5 GHz. IEEE 802.11ad is a transmission specification that uses beamforming technology to provide speeds of up to 7 Gbps, making it suitable for high bitrate video streaming, such as large amounts of data or uncompressed HD video. However, the 60GHz frequency band has a disadvantage in that it is difficult to pass through obstacles, and therefore, it can be used only between devices in a near space.

Recently, as a next generation wireless LAN standard after 802.11ac and 802.11ad, discussions for providing high-efficiency and high-performance wireless LAN communication technology in a high density environment have been continuing. That is, in the next generation wireless LAN environment, communication with high frequency efficiency should be provided in the presence of a high density station and an access point (AP), and various techniques are required to realize this.

The present invention has an object to provide high-efficiency / high-performance wireless LAN communication in a high-density environment as described above.

An object of the present invention is to automatically detect a format of a corresponding packet through information included in a preamble of a wireless LAN packet and distinguish legacy / non-legacy packets.

In order to solve the above problems, the present invention provides a wireless communication method and a wireless communication terminal as described below.

First, according to an embodiment of the present invention, there is provided a wireless communication terminal comprising: a transceiver for transmitting and receiving a radio signal; And a processor for controlling operation of the terminal, wherein the processor receives a wireless packet through the transceiver, the wireless packet including a legacy preamble for a legacy terminal and a non-legacy preamble for a non-legacy terminal And determines whether the wireless packet is a non-legacy packet based on a modulation scheme used for the non-legacy preamble of the received wireless packet.

According to an embodiment of the present invention, the non-legacy preamble includes a non-legacy signal field (SIG), a non-legacy short training field (STF) and a non-legacy long training field (LTF) And determines the wireless packet as a non-legacy packet if a modulation scheme not used in the legacy preamble is used in at least one of the non-legacy STF and the non-legacy LTF.

In this case, when the non-legacy STF is modulated using at least some constellation point sets constituting? / 4-Quadrature Phase Shift Keying (? / 4-QPSK) It is judged as a legacy packet.

The? / 4-QPSK includes a first constellation point set having the same phase as QPSK (Quadrature Phase Shift Keying), and a second constellation point set having a phase difference of? / 4 with the first constellation point. Point set, and the processor determines the wireless packet as a non-legacy packet when the non-legacy STF is modulated using the second set of constraint points.

In addition, when the non-legacy LTF is modulated with QBPSK (Quadrature Binary Phase Shift Keying), the processor determines the wireless packet as a non-legacy packet.

According to another embodiment of the present invention, the non-legacy preamble includes a non-legacy signal field (SIG), a non-legacy short training field (STF) and a non-legacy long training field (LTF) , And determines whether the wireless packet is a non-legacy packet based on a modulation technique used for the non-legacy SIG.

At this time, if the first symbol of the non-legacy SIG is modulated with QBPSK and the second symbol of the non-legacy SIG is modulated with BPSK (Binary Phase Shift Keying), the processor converts the wireless packet into non-legacy Packet.

According to another aspect of the present invention, there is provided a wireless communication method of a terminal, comprising: receiving a wireless packet including a legacy preamble for a legacy terminal and a non-legacy preamble for a non-legacy terminal; And determining whether the wireless packet is a non-legacy packet based on a modulation scheme used for the non-legacy preamble of the received wireless packet; And a wireless communication method.

According to the embodiment of the present invention, when performing wireless communication, it is possible to quickly and accurately detect a specific wireless LAN communication mode based on a received signal in a communication state between terminals supporting a plurality of communication methods.

In addition, according to the embodiment of the present invention, it is possible to quickly distinguish between legacy packets and non-legacy packets, thereby reducing unnecessary power wastage and data transmission / reception delays.

1 illustrates a wireless LAN system in accordance with an embodiment of the present invention.
2 illustrates a wireless LAN system according to another embodiment of the present invention.
3 is a block diagram illustrating a configuration of a station according to an embodiment of the present invention;
4 is a block diagram illustrating a configuration of an access point according to an embodiment of the present invention;
5 is a view schematically illustrating a process in which a STA establishes a link with an AP;
6 illustrates various types of PSK (Phase Shift Keying) modulation schemes.
7 shows a configuration of an IEEE 802.11a packet;
8 illustrates a configuration of an IEEE 802.11n packet;
9 shows a configuration of an IEEE 802.11ac packet;
10 to 12 illustrate a packet configuration of a non-legacy packet according to an embodiment of the present invention and a data communication method using the packet configuration.

As used herein, terms used in the present invention are selected from general terms that are widely used in the present invention while taking into account the functions of the present invention. However, these terms may vary depending on the intention of a person skilled in the art, custom or the emergence of new technology. Also, in certain cases, there may be a term arbitrarily selected by the applicant, and in this case, the meaning thereof will be described in the description of the corresponding invention. Therefore, it is intended that the terminology used herein should be interpreted relative to the actual meaning of the term, rather than the nomenclature, and its content throughout the specification.

Throughout the specification, when a configuration is referred to as being "connected" to another configuration, it is not limited to the case where it is "directly connected," but also includes "electrically connected" do. Also, when an element is referred to as " including " a specific element, it is meant to include other elements, rather than excluding other elements, unless the context clearly dictates otherwise. In addition, the limitations of " above " or " below ", respectively, based on a specific threshold value may be appropriately replaced with "

This application claims priority based on Korean Patent Application Nos. 10-2014-0111018 and 10-2014-0165686, and the embodiments and descriptions described in the above applications, which form the basis of priority, Are to be included in the detailed description of the present invention.

1 illustrates a wireless LAN system according to an embodiment of the present invention. A WLAN system includes one or more Basic Service Sets (BSSs), which represent a collection of devices that can successfully communicate and communicate with one another. In general, a BSS can be divided into an infrastructure BSS (infrastructure BSS) and an independent BSS (IBSS). FIG. 1 shows the infrastructure BSS.

1, an infrastructure BSS (BSS1, BSS2) includes one or more stations STA1, STA2, STA3, STA4, STA5, an access point (PCP / AP) 1, PCP / AP-2), and a distribution system (DS) for connecting a plurality of access points (PCP / AP-1, PCP / AP-2).

A station (STA) is an arbitrary device including a medium access control (MAC) conforming to the IEEE 802.11 standard and a physical layer interface for a wireless medium, and is broadly referred to as a non-access point non-AP) station as well as an access point (AP). In this specification, the term 'terminal' may refer to a non-AP STA or an AP, or may be used to refer to both. The station for wireless communication includes a processor and a transmit / receive unit, and may further include a user interface unit, a display unit, and the like according to an embodiment. The processor may perform various processes for generating frames to be transmitted over the wireless network, processing frames received through the wireless network, and controlling other stations. The transmitting and receiving unit is functionally connected to the processor and transmits and receives a frame through the wireless network for the station.

An access point (AP) is an entity that provides a connection to a distribution system (DS) via a wireless medium for its associated station. In the infrastructure BSS, communication between non-AP stations is performed via an AP. However, when a direct link is established, direct communication is possible between non-AP stations. In the present invention, the AP is used as a concept including a PCP (Personal BSS Coordination Point), and broadly includes a central controller, a base station (BS), a node-B, a base transceiver system (BTS) Controller, and the like.

A plurality of infrastructure BSSs may be interconnected via a distribution system (DS). At this time, a plurality of BSSs connected through a distribution system is called an extended service set (ESS).

2 illustrates an independent BSS that is a wireless LAN system according to another embodiment of the present invention. In the embodiment of FIG. 2, the same or corresponding parts as those of the embodiment of FIG. 1 are not described.

Since the BSS 3 shown in FIG. 2 is an independent BSS and does not include an AP, all the stations STA6 and STA7 are not connected to the AP. An independent BSS is not allowed to connect to the distribution system and forms a self-contained network. In the independent BSS, each of the stations STA6 and STA7 can be directly connected to each other.

3 is a block diagram illustrating a configuration of a station 100 according to an embodiment of the present invention.

The station 100 according to the embodiment of the present invention may include a processor 110, a transceiver 120, a user interface 140, a display unit 150, and a memory 160 .

First, the transceiver unit 120 transmits and receives a wireless signal such as a wireless LAN packet, and may be installed in the station 100 or externally. According to the embodiment, the transceiver 120 may include at least one transceiver module using different frequency bands. For example, the transceiver 120 may include a transceiver module of different frequency bands such as 2.4 GHz, 5 GHz, and 60 GHz. According to one embodiment, the station 100 may include a transmission / reception module using a frequency band of 6 GHz or more and a transmission / reception module using a frequency band of 6 GHz or less. Each of the transmission / reception modules can perform wireless communication with an AP or an external station according to a wireless LAN standard of a frequency band supported by the transmission / reception module. The transceiver unit 120 may operate only one transceiver module at a time or may operate a plurality of transceiver modules at the same time according to the performance and requirements of the station 100. [ When the station 100 includes a plurality of transmission / reception modules, each of the transmission / reception modules may be provided in an independent form, or a plurality of modules may be integrated into one chip.

Next, the user interface unit 140 includes various types of input / output means provided in the station 100. That is, the user interface unit 140 can receive user input using various input means, and the processor 110 can control the station 100 based on the received user input. Also, the user interface unit 140 may perform output based on the instruction of the processor 110 using various output means.

Next, the display unit 150 outputs an image on the display screen. The display unit 150 may output various display objects such as a content executed by the processor 110 or a user interface based on a control command of the processor 110. [ In addition, the memory 160 stores a control program used in the station 100 and various types of data. Such a control program may include an access program required for the station 100 to make an access to an AP or an external station.

The processor 110 of the present invention can execute various commands or programs and process data inside the station 100. [ In addition, the processor 110 controls each unit of the above-described station 100, and can control data transmission / reception between the units. According to an embodiment of the present invention, the processor 110 may execute a program for connection with an AP stored in the memory 160, and may receive a communication setup message transmitted by the AP. In addition, the processor 110 can read information on the priority condition of the station 100 included in the communication setup message, and request a connection to the AP based on the information on the priority condition of the station 100. [ The processor 110 of the present invention may refer to a main control unit of the station 100 and may refer to a control unit for individually controlling the components of the station 100 such as the transmission and reception unit 120, It is possible. The processor 110 controls various operations of transmitting and receiving radio signals of the station 100 according to the embodiment of the present invention. Specific embodiments thereof will be described later.

The station 100 shown in FIG. 3 is a block diagram according to an embodiment of the present invention, and the blocks separately displayed are logically distinguishable from the elements of the device. Thus, the elements of the device described above can be mounted as one chip or as a plurality of chips depending on the design of the device. For example, the processor 110 and the transceiver 120 may be integrated into one chip or may be implemented as a separate chip. In some embodiments of the present invention, some configurations of the station 100, such as the user interface 140 and the display unit 150, may be optionally provided in the station 100.

4 is a block diagram showing the configuration of an AP 200 according to an embodiment of the present invention.

As shown, the AP 200 according to the embodiment of the present invention may include a processor 210, a transceiver 220, and a memory 260. In FIG. 4, the same or corresponding parts as those of the station 100 of FIG. 3 among the configurations of the AP 200 will be omitted.

Referring to FIG. 4, the AP 200 according to the present invention includes a transceiver 220 for operating a BSS in at least one frequency band. 3, the transceiver 220 of the AP 200 may also include a plurality of transceiver modules using different frequency bands. That is, the AP 200 according to the embodiment of the present invention may include two or more transmission / reception modules of different frequency bands, for example, 2.4 GHz, 5 GHz, and 60 GHz. Preferably, the AP 200 may include a transmission / reception module using a frequency band of 6 GHz or more and a transmission / reception module using a frequency band of 6 GHz or less. Each of the transmission / reception modules can perform wireless communication with the station according to the wireless LAN standard of the frequency band supported by the transmission / reception module. The transceiver 220 may operate only one transceiver module at a time or operate a plurality of transceiver modules at the same time according to the performance and requirements of the AP 200. [

Next, the memory 260 stores a control program used in the AP 200 and various data corresponding thereto. Such a control program may include an access program for managing the connection of the station. In addition, the processor 210 controls each unit of the AP 200, and can control data transmission / reception between the units. According to an embodiment of the present invention, processor 210 may execute a program for connection with a station stored in memory 260 and may transmit a communication setup message for one or more stations. At this time, the communication setup message may include information on the connection preference condition of each station. In addition, the processor 210 performs connection setup according to a connection request of the station. The processor 210 controls various operations of transmitting and receiving radio signals of the AP 200 according to an embodiment of the present invention. Specific embodiments thereof will be described later.

FIG. 5 schematically shows a process in which the STA establishes a link with an AP.

Referring to FIG. 5, the link between the STA 100 and the AP 200 is established through three steps of scanning, authentication, and association. First, the scanning step is a step in which the STA 100 acquires access information of a BSS operated by the AP 200. As a method for performing scanning, a passive scanning method in which information is acquired using only a beacon message (S101) periodically transmitted by the AP 200 and a passive scanning method in which the STA 100 transmits a probe request there is an active scanning method in which a probe request is transmitted (S103), a probe response is received from the AP (S105) and access information is acquired.

The STA 100 that has successfully received the wireless access information in the scanning step transmits an authentication request (S107a), receives an authentication response from the AP 200 (S107b), and performs an authentication step do. After the authentication step is performed, the STA 100 transmits an association request (S109a), receives an association response from the AP 200 (S109b), and performs an association step.

On the other hand, the 802.1X-based authentication step S111 and the IP address acquisition step S113 through DHCP can be performed. 5, the authentication server 300 is a server that processes STA 100 and 802.1X-based authentication, and may be physically coupled to the AP 200 or exist as a separate server.

FIG. 6 shows various types of PSK (Phase Shift Keying) modulation schemes. In FIG. 6, each modulation scheme indicates BPSK (Binary Phase Shift Keying), QBPSK (Quadrature Binary PSK), QPSK (Quadrature PSK), and pi / 4-QPSK from the left side.

First, BPSK is a scheme of transmitting 1-bit digital signals (0 and 1) in association with 0 phase and π phase of a subcarrier. QBPSK is similar to BPSK modulation, but there is a difference in that constellation points of subcarriers are distributed in the imaginary axis. QPSK is a method of transmitting 2-bit digital signals (00, 01, 10, 11) in correspondence with four phases of subcarriers. For example, QPSK can transmit a digital signal by correlating 11 to a? / 4 phase, 01 to a 3? / 4 phase, 00 to a 5? / 4 phase, and 10 to a 7? / 4 phase. QPSK can transmit twice as much information in the same frequency bandwidth as BPSK. On the other hand, π / 4-QPSK is one of the modulation schemes derived from QPSK and uses two sets of constellation points with a π / 4 phase difference from each other. That is, the existing QPSK is set as a first constellation point set (i.e., the first set) and a second constellation point set (i.e., the second set) set to have a? / 4 phase difference from the first set / 4-QPSK can perform modulation using the first set and the second set together. FIG. 6 shows a second constellation point of? / 4-QPSK. π / 4-QPSK takes the phase change of subcarriers only at π / 4 intervals, and is determined when the phase change amount is within ± 135 °. Therefore, unlike QPSK, the π / 4-QPSK does not pass through the origin even when the phase changes.

7 to 9 show the configuration of a conventional WLAN packet. More specifically, FIG. 7 shows the configuration of the IEEE 802.11a packet, FIG. 8 shows the configuration of the IEEE 802.11n packet, and FIG. 9 shows the configuration of the IEEE 802.11ac packet. In the embodiment of the present invention, the non-legacy wireless LAN mode is an IEEE 802.11ax wireless LAN mode, and the legacy wireless LAN mode is a wireless LAN mode such as 802.11a, 802.11g, 802.11n, 802.11ac, . In the present invention, the packet format may indicate information on the wireless LAN communication standard mode used in the packet, that is, information on a communication standard mode such as IEEE 802.11a / g / n / ac / ax.

7 to 9, the WLAN packets commonly include a legacy short training field (L-STF), a legacy long training field (L-LTF), and a legacy signal field (L-SIG). At this time, L-STF, L-LTF and L-SIG are composed of two symbols, two symbols and one symbol, respectively, and are modulated into QPSK, BPSK and BPSK, respectively. In the present invention, symbols indicate orthogonal frequency division multiplexing (OFDM) symbols, and the L-STF, L-LTF, and L-SIG will be referred to as a legacy preamble.

Referring to FIG. 7, an 802.11a packet is composed of a legacy preamble and legacy data (Data). The 802.11a terminal extracts rate information and length information included in the L-SIG of the wireless LAN packet, and based on this, regards the portion after L-SIG as legacy data (Data) and decodes the portion. The legacy data is modulated using BPSK, QPSK, 16-QAM (Quadrature Amplitude Modulation) or 64-QAM, and the modulation scheme used may be specified in L-SIG.

Referring to FIG. 8, the 802.11n packet includes a separate HT preamble and HT data (HT-DATA) that can be recognized by the 802.11n terminal after the legacy preamble. The HT preamble consists of HT-SIG, HT-STF and HT-LTF. The HT-SIG is composed of two symbols, and each symbol is modulated with QBPSK. The HT-STF is composed of two symbols, and each symbol is modulated with QPSK. The HT-LTF is composed of a plurality of symbols (N symbols), and each symbol is modulated with BPSK. The HT data (HT-DATA) is modulated using one of BPSK, QPSK, 16-QAM, and 64-QAM, and the modulation scheme used may be specified in the HT-SIG.

The two symbols that make up the HT-SIG of the HT preamble in the 802.11n packet are modulated with an unused modulation scheme, i.e. QBPSK, in the 802.11a packet. The 802.11n terminal identifies the modulation scheme used for the first symbol after the legacy preamble of the received packet and recognizes that the packet is an 802.11n packet if the first symbol is modulated with QBPSK. Here, the modulation technique can be confirmed through the distribution between the I / Q channels of the constellation points of the subcarriers where each data transmission is performed. Thus, 802.11n packets can be distinguished from 802.11a packets (IEEE 802.11g packets in the 2.4 GHz band) based on the modulation scheme used for the HT (High Throughput) preamble after the legacy preamble.

Referring to FIG. 9, the 802.11ac packet includes a separate VHT preamble and VHT data (VHT-DATA) that can be recognized by the 802.11ac terminal after the legacy preamble. The VHT preamble consists of VHT-SIG, VHT-STF and VHT-LTF. The VHT-SIG is composed of two symbols, and each symbol is modulated with BPSK and QBPSK. The VHT-STF is composed of two symbols, each of which is modulated with QPSK. The VHT-LTF is composed of a plurality of symbols (N symbols), and each symbol is modulated into BPSK. The VHT data (VHT-DATA) is modulated using any one of BPSK, QPSK, 16-QAM, 64-QAM and 256-QAM, and the modulation scheme used may be specified in the VHT-SIG.

In the 802.11ac packet, the first symbol constituting the VHT-SIG of the VHT preamble is modulated into BPSK, and the second symbol is modulated into QBPSK. The 802.11ac terminal determines whether the packet is an 802.11ac packet based on the modulation technique used for the first symbol and the second symbol after the legacy preamble of the received packet. That is, when the first symbol of the received packet is modulated to BPSK and the second symbol is modulated to QBPSK, the 802.11ac terminal recognizes that the packet is an 802.11ac packet. The 802.11ac terminal can determine whether the packet is an 802.11n packet through the first symbol and can clearly confirm the packet format when QBPSK modulation is used for the second symbol. More specifically, the 802.11ac terminal distinguishes 802.11n packets from non-802.11n (non-11n) packets based on the modulation technique used for the first symbol, and based on the modulation technique used for the second symbol, Among -11n packets, 802.11a packets and 802.11ac packets can be distinguished.

The operation of discriminating the format of the packet based on the modulation technique used for the preamble of the packet is referred to as auto detection. Since the 802.11n / ac terminal uses automatic detection, it can determine whether the packet is an 802.11n / ac packet before a CRC (Cyclic Redundancy Check) process for the HT / VHT-SIG of the received packet is performed. Therefore, when the received packet is not an 802.11n / ac packet, the 802.11n / ac terminal can reduce power consumption due to unnecessary decoding process and reduce data transmission / reception delay due to 802.11a fallback decision or the like.

10 to 12 illustrate a packet configuration for automatic detection of a non-legacy packet and a data communication method using the packet configuration according to an embodiment of the present invention. In the present invention, non-legacy packets may represent IEEE 802.11ax packets, but the present invention is not limited thereto, and non-legacy packets may represent wireless packets according to other communication standards thereafter. In the embodiment of Figs. 10 to 12, the 802.11ax packet includes a separate HEW preamble and HEW data (HEW-DATA) that can be recognized by the 802.11ax terminal after the legacy preamble. The HEW preamble consists of HEW-SIG, HEW-STF and HEW-LTF. In the present invention, the HEW preamble, HEW-SIG, HEW-STF and HEW-LTF may be referred to as non-legacy preambles, non-legacy SIG, non-legacy STF and non-legacy LTF, respectively.

First, FIG. 10 shows the configuration of a non-legacy packet (802.11ax packet) according to an embodiment of the present invention in comparison with legacy packets (802.11a / n / ac packet). According to one embodiment of the invention, an 802.11ax packet can be distinguished from legacy packets based on the modulation scheme used for the HEW-STF and / or HEW-LTF portions. The non-legacy terminal (802.11ax terminal) transmits at least one of the HEW-STF (non-legacy STF) and HEW-LTF (non-legacy LTF) fields of the 802.11ax packet to the STF and LTF of the legacy packet -STF / LTF, VHT-STF / LTF).

According to one embodiment, the HEW-STF of an 802.11ax packet may be modulated with? / 4-QPSK. In this case, the HEW-STF may be modulated using both the first constellation point set and the second constellation point set constituting? / 4-QPSK, and the second constellation point May be modulated using only a set of points (see FIG. 6). Also, the HEW-LTF can be modulated with QBPSK, respectively. For legacy packets such as 802.11n / ac, the STF is modulated to QPSK and the LTF to BPSK, respectively. Thus, if the STF and LTF of an 802.11ax packet are modulated differently than the legacy STF and the legacy LTF respectively, the 802.11ax terminal can distinguish the packet as a non-legacy packet. That is, when the 802.11ax terminal receives the 802.11n or 802.11ac packet, the legacy STF / LTF part is not normally decoded, so that it can be determined that the packet is a legacy packet. In addition, when an 802.11ax terminal receives an 802.11a packet, the data portion of the 802.11a packet is modulated by one specific technique, whereas the 802.11ax packet differs in the modulation scheme used for HEW-STF and HEW-LTF. It can be determined that the packet is a legacy packet. Furthermore, because QBPSK and π / 4-QPSK are the modulation schemes not used in 802.11a, the 802.11ax terminal distinguishes between legacy and non-legacy packets based on the modulation scheme used in the HEW-STF and HEW-LTF portions can do.

In this way, according to the embodiment of FIG. 10, the 802.11ax terminal can perform automatic detection based on a modulation technique used for fields other than HEW-SIG in the HEW preamble. At this time, since the HEW-SIG is not used for automatic detection of an 802.11ax terminal, it can focus on accurately describing the information of the data field. Meanwhile, in the embodiment of FIG. 10, the number of symbols constituting the HEW-SIG and the modulation technique used for each symbol can be variously modified (TBD).

Fig. 11 shows the configuration of a non-legacy packet (802.11ax packet) according to another embodiment of the present invention in comparison with legacy packets (802.11a / n / ac packet). In accordance with another embodiment of the present invention, an 802.11ax packet may be distinguished from a legacy packet based on a modulation scheme used in the HEW-SIG portion. More specifically, the first symbol of the HEW-SIG of the 802.11ax packet may be modulated with QBPSK and the second symbol with BPSK, respectively.

The 802.11ax terminal determines whether the packet is an 802.11ax packet based on the modulation technique used for the first symbol and the second symbol after the legacy preamble of the received packet. That is, the 802.11ax terminal recognizes that the first symbol of the received packet is modulated with QBPSK and the packet is an 802.11ax packet when the second symbol is modulated with BPSK. That is, in the embodiment of FIG. 11, the 802.11ax packet can be distinguished from the legacy packet by using a combination of modulation schemes not used in the legacy SIG for the HEW-SIG (non-legacy SIG). According to the embodiment of FIG. 11, since it is easy to implement in the automatic detection of the 802.11ax terminal and the 802.11a / n / ac / ax packet is distinguished on the same time line, The burden is the same.

Fig. 12 shows the configuration of a non-legacy packet (802.11ax packet) according to another embodiment of the present invention in comparison with legacy packets (802.11a / n / ac packet). According to another embodiment of the present invention, an 802.11ax packet may be distinguished from non-legacy packets by modifying the field arrangement of the HEW preamble (non-legacy preamble). That is, the 802.11ax terminal changes the order of at least some fields of the HEW preamble to generate an 802.11ax packet, so that the packet can be distinguished from the legacy packet.

According to one embodiment, the HEW preamble of the 802.11ax packet may be configured in the order of HEW-STF, HEW-LTF, and HEW-SIG as shown in FIG. Unlike the previous embodiments in which the packet format is classified by different modulation schemes used for the HEW preamble, in the embodiment of FIG. 12, the non-legacy packet and the legacy packet are changed by changing the configuration of each field constituting the HEW preamble . According to a further embodiment of the present invention, the embodiment of FIG. 12, which changes the order of at least some fields of the HEW preamble, may be implemented in combination with the embodiment of FIG. 10 and / or FIG.

There are many limitations in performing automatic packet detection using only the modulation technique applied to the non-legacy SIG. For example, the number of symbols constituting the HEW-SIG may vary, and automatic detection may cause a restriction on the transmission of information in the data field, which is the main purpose of the SIG. However, if the HEW-STF of the 802.11ax packet exists corresponding to the HT / VHT-SIG position of the 802.11n / ac packet as in the embodiment of FIG. 12, the STF can be easily detected due to correlation, ax terminal can easily distinguish 802.11ax packets from legacy packets (802.11n / ac packets). Since the HEW-SIG contains different information according to the data contained in the transmitted packet and thus the bit stream of the HEW-SIG changes as well, the HEW-STF and the HEW-LTF contain the same information, The terminal can recognize this with high accuracy.

While the present invention has been described by taking the wireless LAN communication as an example, the present invention is not limited thereto and can be applied to other communication systems such as cellular communication. Also, while the method, apparatus, and system of the present invention have been described in connection with specific embodiments thereof, some or all of the elements, acts or operations of the present invention may be implemented using a computer system having a general purpose hardware architecture.

The above-described embodiments of the present invention can be implemented by various means. For example, embodiments of the present invention may be implemented by hardware, firmware, software, or a combination thereof.

In the case of hardware implementation, the method according to embodiments of the present invention may be implemented in one or more Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), Digital Signal Processing Devices (DSPDs), Programmable Logic Devices (PLDs) , FPGAs (Field Programmable Gate Arrays), processors, controllers, microcontrollers, microprocessors, and the like.

In the case of an implementation by firmware or software, the method according to embodiments of the present invention may be implemented in the form of a module, a procedure or a function for performing the functions or operations described above. The software code can be stored in memory and driven by the processor. The memory may be located inside or outside the processor and may exchange data with the processor by any of a variety of well-known means.

It will be understood by those skilled in the art that the foregoing description of the present invention is for illustrative purposes only and that those of ordinary skill in the art can readily understand that various changes and modifications may be made without departing from the spirit or essential characteristics of the present invention. will be. Therefore, the above-described embodiments are to be interpreted in all aspects as illustrative and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

100: station
200: access point

Claims (8)

As a wireless communication terminal,
A transmitting and receiving unit for transmitting and receiving a radio signal; And
And a processor for controlling operation of the terminal,
The processor comprising:
Receiving a wireless packet through the transceiver, the wireless packet including a legacy preamble for a legacy terminal and a non-legacy preamble for a non-legacy terminal,
And determines whether the wireless packet is a non-legacy packet based on a modulation scheme used for the non-legacy preamble of the received wireless packet. The method according to claim 1,
The non-legacy preamble includes a non-legacy signal field (SIG), a non-legacy short training field (STF), and a non-legacy long training field (LTF)
Wherein the processor determines the wireless packet as a non-legacy packet if a modulation scheme not used in the legacy preamble is used in at least one of the non-legacy STF and the non-legacy LTF. 3. The method of claim 2,
Wherein the processor is configured to transmit the wireless packet to a non-legacy STF when the non-legacy STF is modulated using at least some set of constellation points constituting? / 4-Quadrature Phase Shift Keying (? / 4-QPSK) As the wireless communication terminal. The method of claim 3,
The? / 4-QPSK includes a first constellation point set having the same phase as QPSK (Quadrature Phase Shift Keying), and a second constellation point set having a? / 4 phase difference with the first constellation point ≪ / RTI >
Wherein the processor determines the wireless packet as a non-legacy packet if the non-legacy STF is modulated using the second set of compensation points. 3. The method of claim 2,
Wherein the processor identifies the wireless packet as a non-legacy packet when the non-legacy LTF is modulated with QBPSK (Quadrature Binary Phase Shift Keying). The method according to claim 1,
The non-legacy preamble includes a non-legacy signal field (SIG), a non-legacy short training field (STF), and a non-legacy long training field (LTF)
Wherein the processor determines whether the wireless packet is a non-legacy packet based on a modulation technique used for the non-legacy SIG. The method according to claim 6,
Wherein the processor is further configured to: if the first symbol of the non-legacy SIG is modulated with QBPSK and the second symbol of the non-legacy SIG is modulated with BPSK (Binary Phase Shift Keying) The wireless communication terminal. A wireless communication method of a terminal,
Receiving a wireless packet including a legacy preamble for a legacy terminal and a non-legacy preamble for a non-legacy terminal; And
Determining whether the wireless packet is a non-legacy packet based on a modulation scheme used for the non-legacy preamble of the received wireless packet;
Lt; / RTI >

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