Multi-mode wireless transmission method and apparatus

Abstract

A communication method for a next-generation wireless LAN frame according to an embodiment may include: a step of modulating the first symbol of SIG-A of the next-generation wireless LAN frame using a first modulation method; a step of modulating the second symbol of SIG-A of the next-generation wireless LAN frame using a second modulation method; and a step of modulating the STF signal of the next-generation wireless LAN frame in correspondence with the next-generation wireless LAN mode.

Description

Technology Field

[0001] The following description relates to wireless communication technology, specifically to a multimode wireless communication transmission method and device. Background Technology

[0002] With the recent advancement of information and communication technology, various wireless communication technologies are being developed. Among these, Wireless Local Area Network (WLAN) is a technology based on radio frequency technology that enables wireless access to the Internet in homes, businesses, or specific service areas using portable terminals such as Personal Digital Assistants (PDAs), laptop computers, and Portable Multimedia Players (PMPs). Since the establishment of IEEE 802, the standardization body for WLAN technology, in February 1980, much standardization work has been carried out.

[0003] Wireless communication systems are evolving in the direction of transmitting large amounts of data at high speeds. Types of such wireless communication systems include WiBro wireless communication systems, 3GPP LTE systems, and WLAN Very High Throughput (VHT) systems. Accordingly, for the transmission of Next Generation Wireless LAN (NGW) frames, which is the next-generation wireless LAN standard, a transmission method is required that maintains compatibility with the existing IEEE 802.11a / n / ac while achieving high efficiency and high performance. The problem to be solved

[0004] One embodiment provides a high-performance frame transmission method and device while maintaining compatibility with existing wireless LAN standards. means of solving the problem

[0005] A communication method for a next-generation wireless LAN frame according to one embodiment may include: a step of modulating the first symbol of SIG-A of the next-generation wireless LAN frame using a first modulation method; a step of modulating the second symbol of SIG-A of the next-generation wireless LAN frame using a second modulation method; and a step of modulating the STF signal of the next-generation wireless LAN frame in correspondence with the next-generation wireless LAN mode.

[0006] According to one aspect, the step of modulating the first symbol of SIG-A of the next-generation wireless LAN frame using a first modulation method includes the step of modulating the first symbol of SIG-A of the next-generation wireless LAN frame using BPSK, the step of modulating the second symbol of SIG-A of the next-generation wireless LAN frame using a second modulation method includes the step of modulating the second symbol of SIG-A of the next-generation wireless LAN frame using Q-BPSK, and the step of modulating the STF signal of the next-generation wireless LAN frame in correspondence with the next-generation wireless LAN mode may include the step of modulating the STF signal of the next-generation wireless LAN frame to have a phase difference of 90 degrees with VHT-STF.

[0007] According to another aspect, the step of modulating the first symbol of SIG-A of the next-generation wireless LAN frame using a first modulation method includes the step of modulating the first symbol of SIG-A of the next-generation wireless LAN frame using BPSK, the step of modulating the second symbol of SIG-A of the next-generation wireless LAN frame using a second modulation method includes the step of modulating the second symbol of SIG-A of the next-generation wireless LAN frame using BPSK, and the step of modulating the STF signal of the next-generation wireless LAN frame in correspondence with the next-generation wireless LAN mode may include the step of modulating the STF signal of the next-generation wireless LAN frame using Q-BPSK.

[0008] According to another aspect, the communication method of a next-generation wireless LAN frame allows the STF signal to be mapped to BPSK signals at positions (-1, 1) and (1, -1).

[0009] A communication method for a next-generation wireless LAN frame according to one embodiment may include: receiving a communication signal; verifying the first symbol and the second symbol of SIG-A of the communication signal; verifying the STF signal of the communication signal when the first symbol is a BPSK signal and the second symbol is a Q-BPSK signal; and identifying the communication mode of the wireless LAN frame according to the STF signal.

[0010] According to one aspect, the step of identifying the communication mode of the wireless LAN frame according to the STF signal may include the step of determining the communication mode as a next-generation wireless LAN mode when the STF signal has a phase difference of 90 degrees with VHT-STF.

[0011] A communication method for a next-generation wireless LAN frame according to one embodiment may include: receiving a communication signal; verifying the first symbol and the second symbol of SIG-A of the communication signal; verifying the STF signal of the communication signal when the first symbol is a BPSK signal and the second symbol is a BPSK signal; and identifying the communication mode of the wireless LAN frame according to the STF signal.

[0012] According to one aspect, the step of identifying the communication mode of the wireless LAN frame according to the STF signal may include the step of determining the communication mode as a next-generation wireless LAN mode when the STF signal is a Q-BPSK signal.

[0013] A communication method for a next-generation wireless LAN frame according to one embodiment may include: a step of modulating the first symbol of SIG-A of the next-generation wireless LAN frame using a first modulation method; a step of modulating the second symbol of SIG-A of the next-generation wireless LAN frame using a second modulation method; and a step of modulating the third symbol of SIG-A of the next-generation wireless LAN frame in correspondence with a next-generation wireless LAN mode.

[0014] According to one aspect, the step of modulating the first symbol of SIG-A of the next-generation wireless LAN frame using a first modulation method includes the step of modulating the first symbol of SIG-A of the next-generation wireless LAN frame using BPSK, the step of modulating the second symbol of SIG-A of the next-generation wireless LAN frame using a second modulation method includes the step of modulating the second symbol of SIG-A of the next-generation wireless LAN frame using Q-BPSK, and the step of modulating the third symbol of SIG-A of the next-generation wireless LAN frame in correspondence with the next-generation wireless LAN mode may include the step of modulating the third symbol of SIG-A of the next-generation wireless LAN frame to have a phase difference of 90 degrees with VHT-STF.

[0015] According to another aspect, the step of modulating the first symbol of SIG-A of the next-generation wireless LAN frame using a first modulation method includes the step of modulating the first symbol of SIG-A of the next-generation wireless LAN frame using BPSK, the step of modulating the second symbol of SIG-A of the next-generation wireless LAN frame using a second modulation method includes the step of modulating the second symbol of SIG-A of the next-generation wireless LAN frame using BPSK, and the step of modulating the third symbol of SIG-A of the next-generation wireless LAN frame in correspondence with the next-generation wireless LAN mode may include the step of modulating the third symbol of SIG-A of the next-generation wireless LAN frame using Q-BPSK.

[0016] A communication method for a next-generation wireless LAN frame according to one embodiment may include: receiving a communication signal; verifying the first and second symbols of SIG-A of the communication signal; verifying the third symbol of SIG-A when the first symbol is a BPSK signal and the second symbol is a Q-BPSK signal; and identifying the communication mode of the wireless LAN frame according to the third symbol.

[0017] According to one side, the step of identifying the communication mode of the wireless LAN frame according to the third symbol may include the step of determining the communication mode as a next-generation wireless LAN mode when the third symbol has a phase difference of 90 degrees with VHT-STF.

[0018] A communication method for a next-generation wireless LAN frame according to one embodiment may include: receiving a communication signal; verifying the first and second symbols of SIG-A of the communication signal; verifying the third symbol of SIG-A when the first symbol is a BPSK signal and the second symbol is a BPSK signal; and identifying the communication mode of the wireless LAN frame according to the third symbol of SIG-A.

[0019] According to one aspect, the step of identifying the communication mode of the wireless LAN frame according to the third symbol of the SIG-A may include the step of determining the communication mode as a next-generation wireless LAN mode when the third symbol of the SIG-A is a Q-BPSK signal.

[0020] A communication method for a next-generation wireless LAN frame according to one embodiment may include: a step of generating a signal field of the next-generation wireless LAN frame with the same length as the signal field of a very high throughput (VHT) frame; and a step of inputting a predetermined reserved bit among the reserved bits of the signal field structure of the VHT frame as a first value.

[0021] According to one aspect, the method may further include the step of modulating the first symbol of SIG-A of the next-generation wireless LAN frame into BPSK; and the step of modulating the second symbol of SIG-A of the next-generation wireless LAN frame into Q-BPSK.

[0022] According to another aspect, the step of inputting a predetermined reserved bit as a first value among the reserved bits of the signal field structure of the VHT frame may include: a step of inputting the predetermined reserved bit as the first value in the case of a next-generation wireless LAN mode; and a step of inputting the predetermined reserved bit as a second value in the case of a VHT mode.

[0023] A communication method for a next-generation wireless LAN frame according to one embodiment may include: receiving a wireless LAN frame; verifying a predetermined reserved bit among the reserved bits of the signal field structure of a VHT frame among the wireless LAN frames; and identifying the communication mode of the wireless LAN frame according to the identified reserved bit.

[0024] According to one aspect, the step of identifying the communication mode of the wireless LAN frame according to the identified reservation bit may include: a step of determining the communication mode as a next-generation wireless LAN mode when the identified reservation bit is a first value; and a step of determining the communication mode as a VHT mode when the identified reservation bit is a second value.

[0025] A communication method for a next-generation wireless LAN frame according to one embodiment may include the step of generating a signal field of the next-generation wireless LAN frame with the same length as the signal field of the HT (high throughput) frame; and, in the case of a next-generation wireless LAN mode, the step of inputting a reserved bit of the signal field structure of the HT frame as a first value.

[0026] A communication method for a next-generation wireless LAN frame according to one embodiment may include: receiving a wireless LAN frame; verifying a reserved bit of a signal field structure of an HT frame among the wireless LAN frames; and identifying a communication mode of the wireless LAN frame according to the identified reserved bit. Effects of the invention

[0027] One embodiment enables the transmission of NGW frames that maintain compatibility with IEEE 802.11a / n / ac and enable high-performance discrimination. Brief explanation of the drawing

[0028] Figure 1 is a diagram showing a conventional wireless LAN frame structure. FIG. 2 is a diagram showing a next-generation wireless LAN frame structure according to one embodiment. Figure 3 is a diagram showing a conventional wireless LAN frame transmission method. FIG. 4 is a diagram showing a transmission method of a next-generation wireless LAN frame according to one embodiment. FIG. 5 is another example illustrating a transmission method of a next-generation wireless LAN frame according to one embodiment. FIG. 6 is a diagram illustrating a method of transmitting by including frame type information in a signal field according to one embodiment. FIG. 7 is a diagram showing a method for detecting a VHT frame according to one embodiment. FIG. 8 is another example illustrating a transmission method of a next-generation wireless LAN frame according to one embodiment. FIG. 9 is a diagram illustrating a method for detecting an HT frame according to one embodiment. FIGS. 10 to 21 are drawings illustrating a communication method of a next-generation wireless LAN frame according to an embodiment. Figure 22 is a diagram showing the physical layer structure of IEEE 802.11. FIG. 23 is a diagram showing the structure of a communication device for a next-generation wireless LAN frame according to one embodiment. Specific details for implementing the invention

[0029] Hereinafter, embodiments will be described in detail with reference to the attached drawings.

[0030] Figure 1 is a diagram showing a conventional wireless LAN frame structure.

[0031] Existing wireless LANs may include legacy standards 11a / b / g and high-throughput (HT) standards 11n and very high-throughput (VHT) from the IEEE 802.11 group. The wireless LAN PPDU (PLCP protocol data unit) frame structure can be shown in Fig. 1.

[0032] Wireless LANs can support transmission methods in Legacy, HT (High Throughput), and VHT (Very High Throughput) modes. IEEE 802.11a / g is classified as a Legacy type, IEEE 802.11n as HT mode, and IEEE 802.11ac as VHT mode.

[0033] When transmitting a PPDU, the wireless LAN system may include signal information in the header field to allow the receiving end to properly restore the PPDU. Since this signal information is very important for restoring the PPDU data, it is transmitted at the lowest MCS to be resistant to channel changes and noise. Legacy PPDU (110) can be divided into L-STF, L-LTF, L-SIG, and data. HT PPDU (120) can be divided into L-STF, L-LTF, L-SIG, HT-SIG, HT-STF, HT-LTF, and data, and VHT PPDU (130) can be divided into L-STF, L-LTF, L-SIG, VHT-SIGA, VHT-STF, VHT-LTF, VHT-SIGB, and data.

[0034] L-STF (Legacy short training field) can be used for carrier sensing to detect whether a signal is present in the channel currently in use, automatic gain control to match the wireless signal input to the antenna to the operating range of the analog circuit and the analog-to-digital converter, and for coarse carrier frequency offset correction.

[0035] L-LTF (Legacy long training field) can be used for fine carrier frequency offset correction and symbol synchronization, and for channel response estimation for demodulation of L-SIG field and HT-SIG field or VHT-SIG field. Additionally, the signal-to-noise ratio can be estimated using the principle of repeating two symbols.

[0036] By using iterative sequences such as L-STF and L-LTF, various channel characteristics such as interference, Doppler, and delay spread can be estimated.

[0037] Signal fields such as L-SIG (Legacy signal field), HT-SIG (HT signal field), and VHT-SIG (VHT signal field) may contain control information necessary for a terminal or AP receiving the PPDU to demodulate the received PPDU. Examples include packet length, MCS, bandwidth and channel encoding scheme, and supported transmission technologies such as beamforming, STBC, smoothing, MU-MIMO, and Short Guard interval mode. In the case of VHT-SIG, it is divided into the VHT-SIGA field and VHT-SIGB field to transmit public control information and dedicated information required for a specific MU group. It may also include ID information such as a group ID and a partial association ID (PAID).

[0038] In addition, L-SIG, HT-SIG, and VHT-SIG can be used as a means to indicate the type of frame. By transmitting the transmission symbols of L-SIG, HT-SIG, and VHT-SIG as BPSK or Q-BPSK (Quadrature BPSK), it is provided to the terminal receiving the frame to know what type of frame it has received. Q-BPSK is a signal obtained by rotating the BPSK signal by 90 degrees, and it is a modulation scheme that guarantees maximum orthogonality compared to BPSK.

[0039] In the case of 802.11n frames, both HT-SIG symbols are transmitted as Q-BPSK, and two symbols that are phase-rotated 90 degrees relative to the BPSK of a legacy frame are detected to be recognized as an 802.11n frame. When transmitting an 802.11n frame, the L-SIG rate is set to 6 Mbps and the length is specified to be the time the frame occupies the channel; therefore, after determining whether the rate is 6 Mbps, if it is 6 Mbps, it is possible to determine whether the HT frame detection is BPSK or Q-BPSK.

[0040] In the case of 802.11ac frames, the first symbol of the VHT-SIG is transmitted as BPSK, and the second symbol is transmitted as Q-BPSK. Since the first symbol is BPSK, 11n devices recognize it as a legacy frame, and 11ac devices recognize the second symbol as Q-BPSK and recognize it as a VHT frame.

[0041] HT-STF (HT short training field) or VHT-STF (VHT short training field) is used to improve the gain control performance of AGC, and additional gain control is absolutely necessary, especially when using beamforming technology.

[0042] HT-LTF (HT long training field) or VHT-LTF (VHT long training field) can be used by a terminal or AP to estimate the channel. Unlike legacy standards, 11n or 11ac standards increased throughput by increasing the number of subcarriers used; therefore, a new LTF was defined for data recovery in addition to L-LTF. In the case of VHT-LTF, it may also include pilot signals for offset correction.

[0043] The data field contains data information to be transmitted. This field can be transmitted by converting the MAC layer's MPDU into a PSDU, including the service field and tail bit.

[0044] FIG. 2 is a diagram showing a next-generation wireless LAN frame structure according to one embodiment.

[0045] Referring to 210, the frame structure of the next-generation wireless LAN transmission standard, NGW, is shown. To maintain backward compatibility with existing wireless LAN standard transmission methods, it includes L-STF, L-LTF, and L-SIG, and includes an NGW signal field and a preamble to enable the transmission of signaling information for recovering NGW DATA. After the signal field and preamble, variable-length DATA information may be included.

[0046] The DATA of the above NGW frame may include data tones and pilot tones, and the pilot can maintain Doppler robustness by using a traveling pilot to change its position for each symbol during transmission. Alternatively, a midamble of the NGW-LTF structure may be periodically included between data symbols. Since the use of midambles allows the wireless terminal to adapt more quickly to channel and phase changes, it can be used to improve performance in outdoor environments. Additionally, the length of the guard interval of the DATA frame is variable, so the length of the guard interval can be variably adjusted according to channel environment conditions by the signal field indicator to make it robust against delay spread.

[0047] Referring to 220, another example of an NGW frame structure is shown, in which NGW-SIG-A, NGW-STF, NGW-LTF, NGW-SIG-B and DATA may be included after L-STF, L-LTF, and L-SIG.

[0048] NGW-SIG-A can provide a single user with information such as packet length, MCS, bandwidth and channel encoding scheme, beamforming, STBC, smoothing, MU-MIMO, Short Guard interval mode, delay spread state, channel quality, group identification, and partial association identification that can be used to decode packets.

[0049] NGW-STF enables fine gain control when using beamforming or multi-antenna transmission methods. NGW-LTF can be used for channel estimation and phase tracking for NGW data frame recovery.

[0050] DATA may include data values ​​transmitted in a manner consistent with the above signal information. The DATA field may include a periodic pilot sequence as a reference signal for tracking and compensating for phase, signal magnitude, residual frequency offset, etc., when restoring the transmitted data according to the information specified in the signal field. The pilot sequence may operate in either a traveling pilot mode or a fixed point pilot mode depending on the pilot sequence mode information specified in the signal field. In fixed pilot mode, the pilot's position is fixed and exists at the same location for every data symbol, whereas in traveling pilot mode, the pilot's position rotates periodically for every symbol and returns to its original position after a certain number of symbols. When using a traveling pilot, it can help overcome channel changes even if the channel state changes significantly due to Doppler shift or delay spread.

[0051] Figure 3 is a diagram showing a conventional wireless LAN frame transmission method.

[0052] Legacy (310) frame transmission method can transmit the first symbol of the signal field in QPSK and the second symbol in QPSK modulation.

[0053] The HT (320) frame transmission method can transmit the first symbol of the signal field in Q-BPSK and the second symbol in Q-BPSK modulation.

[0054] The VHT (330) frame transmission method can transmit the first symbol of the signal field in BPSK and the second symbol in Q-BPSK modulation.

[0055] FIG. 4 is a diagram showing a transmission method of a next-generation wireless LAN frame according to one embodiment.

[0056] Referring to the NGW (Type-1a) (410) frame transmission method, the first symbol of NGW-SIG-A can be modulated into BPSK and the second symbol into Q-BPSK. As explained in FIG. 3, since it is the same modulation method as VHT-SIG-A, the information of NGW-SIG-A can be made compatible with the VHT device, thereby enabling spoofing or power saving of the VHT device. Spoofing refers to a function that prevents terminals using the existing standard from accessing the channel for a period calculated by the rate and length information listed in the signal field, by recognizing that they have received the existing frame. Power saving refers to a function that stops subsequent processing and enters power saving mode based on the ID information in the signal field if the receiving terminal is not receiving the frame. When this frame is received, the NGW-STF is transmitted as BPSK rotated 135 degrees counterclockwise from the X-axis, making it 90 degrees different from the existing VHT-STF so that the receiving end can determine the packet type. In VHT-STF, BPSK signals are mapped to positions (1, 1) and (-1, -1) and transmitted, whereas in NGW-STF, BPSK signals are mapped to positions (-1, 1) and (1, -1) and transmitted, so the two signals have a phase difference of 90 degrees. Based on the BPSK and Q-BPSK signals in the signal field preceding VHT-STF or NGW-STF, it is recognized as a VHT or NGW frame, and the frame mode is recognized by recognizing the phase of the subsequent STF signal. The VHT device performs spoofing based on the signal field information recognized as L-SIG and VHT-SIG-A, and the NGW device simultaneously performs frame type detection and automatic gain control in NGW-STF.

[0057] The NGW (Type-1b) (420) frame transmission method can be distinguished from legacy frame formats by transmitting both symbols of NGW-SIG-A in BPSK modulation and transmitting NGW-STF in Q-BPSK. In this way, when both symbols following L-SIG are transmitted in BPSK, legacy terminals, HT terminals, and VHT terminals can recognize this frame as a legacy frame. The NGW terminal can determine whether this frame is a legacy frame or an NGW frame by distinguishing between BPSK and Q-BPSK at the NGW-STF location. In the case of an NGW frame, NGW-STF is transmitted in Q-BPSK, and in the case of a legacy frame, it is transmitted as a BPSK signal, so the frame mode can be distinguished by the 90-degree phase difference of the above signals. The reason that only the BPSK signal needs to be considered in the case of a legacy frame is that in the case of an NGW frame, the rate is set to 6 Mbps and transmitted.

[0058] The NGW (Type 2) frame transmission method represents a method of transmitting NGW-SIG-A symbols with a length of three symbols to include more signal field information than the NGW (Type 1) method.

[0059] The NGW (Type-2a) (430) frame transmission method transmits the first symbol of NGW-SIG-A as BPSK and the second symbol as Q-BPSK so that both the VHT terminal and the NGW terminal can utilize the corresponding signal fields, and transmits the third symbol by rotating it 135 degrees counterclockwise on the X-axis so that the VHT frame and the NGW frame can be distinguished. The third symbol of NGW-SIG-A of the NGW frame has a 90-degree phase difference from VHT-STF of the VHT frame, so the VHT frame and the NGW frame can be distinguished from the received frame.

[0060] The NGW (Type-2b) (440) frame transmission method can distinguish between Legacy frames and NGW frames by transmitting the first and second symbols of NGW-SIG-A as BPSK and the third symbol as Q-BPSK. When transmitted in this way, since the first and second symbols of NGW-SIG-A are BPSK, legacy terminals, HT terminals, and VHT terminals determine that this frame is a legacy frame and spoof based on the rate and length information of the signal field. On the other hand, the NGW terminal detects that the first and second symbols are BPSK and the third symbol is Q-BPSK and determines that it is an NGW frame. Since the NGW terminal only needs to determine whether it is a legacy frame or an NGW frame when the rate is 6 Mbps, it only needs to determine whether it is BPSK or Q-BPSK at the third symbol position of NGW-SIG-A.

[0061] A communication method for a next-generation wireless LAN frame according to one embodiment can determine the type of frame by modulating and transmitting symbols. Additionally, regarding the communication method for a next-generation wireless LAN frame, a method of transmitting including frame type information in a signal field is described with reference to FIGS. 5 and FIGS. 7.

[0062] FIG. 5 is another example illustrating a transmission method of a next-generation wireless LAN frame according to one embodiment.

[0063] Figure 5 illustrates a method of transmitting by including frame type information in the signal field, wherein the modulation method of the signal field is maintained the same as that of a VHT mode frame, but the Reserved bit is used to enable the NGW device to recognize that it is in NGW frame mode.

[0064] As described in FIG. 3, the Legacy (510) frame transmission method can transmit the first symbol of the signal field in QPSK and the second symbol in QPSK modulation. The HT (520) frame transmission method can transmit the first symbol of the signal field in Q-BPSK and the second symbol in Q-BPSK modulation. The VHT (530) frame transmission method can transmit the first symbol of the signal field in BPSK and the second symbol in Q-BPSK modulation.

[0065] In the NGW (Type-3) (540) frame transmission method, the modulation method of the signal field can be maintained the same as that of the VHT mode frame as described in 530. At this time, the VHT frame can be distinguished using the Reserved bit. The method of distinguishing between VHT mode and NGW using the Reserved bit will be explained in detail in FIGS. 6 and 7.

[0066] FIG. 6 is a diagram illustrating a method of transmitting by including frame type information in a signal field according to one embodiment.

[0067] FIG. 6a illustrates a method for transmitting an NGW (Type-3a) frame, wherein the NGW frame of the NGW (Type-3a) can have the same signal field structure as the VHT frame format. The VHT frame has 3 Reserved bits, and the NGW mode and VHT mode can be distinguished by using at least one of these Reserved bits. Accordingly, frame format information can be defined using at least one bit value among the Reserved bits (611, 612, 613). For example, if the Reserved bit is 0, it can be defined as NGW mode and if the Reserved bit is 1, as VHT mode; or if the Reserved bit is 1, it can be defined as NGW mode and if the Reserved bit is 0, as VHT mode.

[0068] Since the NGW (Type-3a) frame transmission method can be transmitted by modulating the first symbol of NGW-SIG-A to BPSK and the second symbol to Q-BPSK, Legacy terminals and HT terminals can be recognized as Legacy mode, and VHT terminals can be recognized as VHT mode. The NGW can determine the NGW mode using the Reserved bit.

[0069] FIG. 6b illustrates a method for transmitting an NGW (Type-3b) frame. NGW (Type-3b) is a frame format in which other signal information (signal information 1, 2, 3, 4) is newly defined, excluding the location of the Reserved bits (651, 652, 653). A device receiving the frame can distinguish the frame mode using at least one bit value among the Reserved bits (651, 652, 653), as in NGW (Type-3a). For example, if the Reserved bit is 0, it can be defined as NGW mode and if the Reserved bit is 1, as VHT mode; or if the Reserved bit is 1, it can be defined as NGW mode and if the Reserved bit is 0, as VHT mode.

[0070] The NGW (Type-3b) frame transmission method modulates the first symbol of NGW-SIG-A to BPSK and the second symbol to Q-BPSK for transmission, so it will be recognized as Legacy mode by Legacy terminals and HT terminals, and as VHT mode by VHT terminals, and in the case of NGW, the NGW mode can be determined using the Reserved bit.

[0071] FIG. 7 is a diagram showing a method for detecting a VHT frame according to one embodiment.

[0072] FIG. 7 is a diagram illustrating NGW-SIG-A of an NGW (Type-3b) frame to explain an example of detecting a frame mode. The NGW (Type-3b) frame is a frame format newly defined for NGW, where signal information (signal information 1, 2, 3, 4) other than the Reserved bit positions is used. A device receiving the frame can distinguish the frame mode by using at least one bit value among the Reserved bits to provide frame format information, such as in NGW (Type-3a).

[0073] Referring to FIG. 7a, for example, NGW (Type-3b1) (700) can detect a frame mode (710) using the value of the first Reserved bit (710) among the Reserved bits (710, 711, 712). Referring to FIG. 7b, for example, NGW (Type-3b2) (720) can detect a frame mode (731) using the bit value of the second Reserved bit (731) among the Reserved bits (730, 731, 732). Referring to FIG. 7c, for example, NGW (Type-3b3) (740) can detect a frame mode (752) using the bit value of the third Reserved bit (752) among the Reserved bits (750, 751, 752).

[0074] The modulation method of the above NGW (Type-3a) and NGW (Type-3b) signal fields is maintained identically to that of the VHT mode frame, but the Reserved bit is used to enable the NGW device to recognize that it is in the NGW frame mode. In the case of the Legacy signal field, the error detection performance of the parity bit is poor, and the reserved bit is already used for other purposes, making it difficult to use for frame mode detection. However, in the case of HT-SIG or VHT-SIG, it has a CRC field and has excellent error detection performance, so it can be used for frame mode detection.

[0075] FIG. 8 is another example illustrating a transmission method of a next-generation wireless LAN frame according to one embodiment.

[0076] Legacy (810) frames can transmit the first symbol of the signal field in QPSK and the second symbol in QPSK modulation. HT (820) frames can transmit the first symbol of the signal field in Q-BPSK and the second symbol in Q-BPSK modulation. VHT (830) frames can transmit the first symbol of the signal field in BPSK and the second symbol in Q-BPSK modulation.

[0077] The NGW (Type-4) (840) frame transmission method transmits both symbols using Q-BPSK modulation, just like HT-SIG, so that HT devices and VHT devices can recognize this frame as an HT frame, and Legacy devices can recognize it as a Legacy frame. The NGW device can determine whether it is an NGW frame or not by using the Reserved bit. For example, if the Reserved bit is 0, it is an NGW frame, and if the Reserved bit is 1, it is recognized as an HT frame.

[0078] FIG. 9 is a diagram illustrating a method for detecting an HT frame according to an embodiment.

[0079] In FIG. 9a, the NGW (Type-4a) (910) frame transmission method can identify an NGW frame using a Reserved bit (911). The NGW (Type-4a) transmits both symbols in the same way as HT-SIG using Q-BPSK modulation, so that the HT device and VHT device recognize the frame as an HT frame, and the Legacy device recognizes the frame as a Legacy frame. The NGW (Type-4a) device can determine whether it is an NGW frame or not by using the Reserved bit (911). For example, if the Reserved bit (911) is 0, it is an NGW frame, and if the Reserved bit (911) is 1, it can be recognized as an HT frame.

[0080] In FIG. 9b, the NGW (Type-4b) (950) is a frame format newly defined for NGW, with signal information (signal information 1, 2, 3) other than the Reserved bit position. As described in FIG. 9a, the NGW (Type-4b) (950) frame transmission method transmits both symbols using the Q-BPSK modulation method, just like HT-SIG, so that HT devices and VHT devices can recognize the frame as an HT frame, and Legacy devices can recognize it as a Legacy frame. The NGW (Type-4b) device can determine whether it is an NGW frame or not by using the Reserved bit (951). For example, if the Reserved bit (951) is 0, it is an NGW frame, and if the Reserved bit (951) is 1, it can be recognized as an HT frame.

[0081] FIG. 10 is a diagram illustrating a communication method of a next-generation wireless LAN frame according to one embodiment.

[0082] FIG. 10 illustrates a method for transmitting an NGW (Type-1a) frame, and the method for transmitting a next-generation wireless LAN frame can be performed by a communication device for next-generation wireless LAN frames. A next-generation wireless LAN frame can be transmitted by a transmitting unit of a communication device for next-generation wireless LAN frames, and a next-generation wireless LAN frame can be received by a receiving unit, and can be applied to the following embodiments.

[0083] In step (1010), the transmitter can modulate the first symbol of SIG-A of the next-generation wireless LAN frame into BPSK.

[0084] In step (1020), the transmitter can modulate the second symbol of SIG-A of the next-generation wireless LAN frame into Q-BPSK.

[0085] In step (1030), the transmitter can modulate the STF signal of the next-generation wireless LAN frame to have a phase difference of 90 degrees with the VHT-STF. Since the NGW-STF signal can be transmitted with the BPSK signal mapped to the (-1, 1) and (1, -1) positions, and the VHT-STF can be transmitted with the BPSK signal mapped to the (1, 1) and (-1, -1) positions, the NGW-STF and VHT-STF signals can be modulated to have a phase difference of 90 degrees.

[0086] A communication device for a next-generation wireless LAN frame according to one embodiment can recognize a frame mode by recognizing a VHT or NGW frame based on BPSK and Q-BPSK signals in a signal field, and then recognizing the phase of an STF signal.

[0087] FIG. 11 is a diagram illustrating a communication method of a next-generation wireless LAN frame according to one embodiment.

[0088] FIG. 11 illustrates a method for receiving an NGW (Type-1a) frame, and the method for receiving a next-generation wireless LAN frame can be performed by a communication device for the next-generation wireless LAN frame.

[0089] In step (1110), the receiver can receive a communication signal.

[0090] In step (1120), the receiver can verify the first and second symbols of the SIG-A of the communication signal.

[0091] In step (1130), the receiver can check the STF signal of the communication signal if the first symbol is BPSK and the second symbol is a Q-BPSK signal.

[0092] In step (1140), the receiver can identify the communication mode of the wireless LAN frame according to the STF signal. At this time, if the NGW-STF signal has a phase difference of 90 degrees with the VHT-STF, the receiver can determine the communication mode as the next-generation wireless LAN mode. If the STF signal has no phase difference with the VHT-STF, the receiver can determine the communication mode as the VHT mode.

[0093] FIG. 12 is another example illustrating a communication method of a next-generation wireless LAN frame according to one embodiment.

[0094] FIG. 12 illustrates a method for transmitting an NGW (Type-1b) frame, wherein in step (1210), the transmitter can modulate the first symbol of SIG-A of the next-generation wireless LAN frame into BPSK.

[0095] In step (1220), the transmitter can modulate the second symbol of SIG-A of the next-generation wireless LAN frame into BPSK.

[0096] In step (1230), the transmitter can modulate the STF signal of the next-generation wireless LAN frame into Q-BPSK.

[0097] FIG. 13 is another example illustrating a communication method of a next-generation wireless LAN frame according to one embodiment.

[0098] FIG. 13 illustrates a method for receiving an NGW (Type-1b) frame, in which the receiver can receive a communication signal in step (1310).

[0099] In step (1320), the receiver can identify the first and second symbols of the SIG-A of the communication signal.

[0100] In step (1330), the receiver can check the STF signal of the communication signal if the first symbol is a BPSK signal and the second symbol is a BPSK signal.

[0101] In step (1340), the communication mode of the wireless LAN frame can be identified according to the STF signal. At this time, if the STF signal is a Q-BPSK signal, the communication mode can be determined as a next-generation wireless LAN mode. If the STF signal is a BPSK signal, the communication mode can be determined as a legacy mode.

[0102] FIG. 14 is another example illustrating a communication method of a next-generation wireless LAN frame according to one embodiment.

[0103] FIG. 14 illustrates a method for transmitting an NGW (Type-2a) frame, wherein in step (1410), the transmitter can modulate the first symbol of SIG-A of the next-generation wireless LAN frame into BPSK.

[0104] In step (1420), the transmitter can modulate the second symbol of SIG-A of the next-generation wireless LAN frame into Q-BPSK.

[0105] In step (1430), the transmitter can modulate the third symbol of SIG-A of the next-generation wireless LAN frame to have a 90-degree phase difference with VHT-STF. At this time, the STF signal can be mapped to BPSK signals at positions (-1, 1) and (1, -1).

[0106] FIG. 15 is another example illustrating a communication method of a next-generation wireless LAN frame according to one embodiment.

[0107] FIG. 15 illustrates a method for receiving an NGW (Type-2a) frame, wherein in step (1510), the receiver can receive a communication signal.

[0108] In step (1520), the receiver can identify the first and second symbols of the SIG-A of the communication signal.

[0109] In step (1530), the receiver can identify the third symbol of SIG-A if the first symbol is a BPSK signal and the second symbol is a Q-BPSK signal.

[0110] In step (1540), the receiver can identify the communication mode of the wireless LAN frame based on the third symbol. If the third symbol has a 90-degree phase difference from VHT-STF, the communication mode can be determined as the next-generation wireless LAN mode. Additionally, if the third symbol has no phase difference from VHT, the communication mode can be determined as the VHT mode.

[0111] FIG. 16 is another example illustrating a communication method of a next-generation wireless LAN frame according to one embodiment.

[0112] FIG. 16 illustrates a method for transmitting an NGW (Type-2b) frame, wherein in step (1610), the transmitter can modulate the first symbol of SIG-A of the next-generation wireless LAN frame into BPSK.

[0113] In step (1620), the transmitter can modulate the second symbol of SIG-A of the next-generation wireless LAN frame into BPSK.

[0114] In step (1630), the transmitter can modulate the third symbol of SIG-A of the next-generation wireless LAN frame into Q-BPSK.

[0115] FIG. 17 is another example illustrating a communication method of a next-generation wireless LAN frame according to one embodiment.

[0116] FIG. 17 illustrates a method for receiving an NGW (Type-2b) frame, in which the receiver can receive a communication signal at step (1710).

[0117] In step (1720), the receiver can identify the first and second symbols of the SIG-A of the communication signal.

[0118] In step (1730), the receiver can identify the third symbol of SIG-A if the first symbol is a BPSK signal and the second symbol is a BPSK signal.

[0119] In step (1740), the receiver can identify the communication mode of the wireless LAN frame according to the third symbol of SIG-A. If the third symbol of SIG-A is a Q-BPSK signal, the communication mode can be determined as a next-generation wireless LAN mode. If the third symbol of SIG-A is a BPSK signal, the communication mode can be determined as a legacy mode.

[0120] FIG. 18 is another example illustrating a communication method of a next-generation wireless LAN frame according to one embodiment.

[0121] Figure 18 illustrates a method for transmitting NGW (Type-3a) and NGW (Type-3b) frames.

[0122] In step (1810), the transmitter can generate a signal field of a next-generation wireless LAN frame with the same length as the signal field of a VHT frame. At this time, the signal field of the next-generation wireless LAN frame can be generated identically to the signal field structure of the VHT frame, or differently from the signal field structure of the VHT frame.

[0123] In step (1820), the transmitter may input one of the reserved bits of the signal field structure of the VHT frame as the first value. For example, a predetermined reserved bit of the signal field structure of the VHT frame may be input as the first value. At this time, in the case of next-generation wireless LAN mode, a predetermined reserved bit may be input as the first value, and in the case of VHT mode, a predetermined reserved bit may be input as the second value.

[0124] In step (1830), the transmitter can modulate the first symbol of NGW-SIG-A of the next-generation wireless LAN frame into BPSK, and in step (1840), the transmitter can modulate the second symbol of NGW-SIG-A of the next-generation wireless LAN frame into Q-BPSK.

[0125] FIG. 19 is another example illustrating a communication method of a next-generation wireless LAN frame according to one embodiment.

[0126] FIG. 19 illustrates a method for receiving NGW (Type-3a) and NGW (Type-3b) frames, wherein in step (1910), the receiver can receive wireless LAN frames.

[0127] In step (1920), the receiver can check the reserved bits among the reserved bits of the signal field structure of the VHT frame among the wireless LAN frames.

[0128] In step (1930), the receiver can identify the communication mode of the wireless LAN frame according to the identified reserved bit. At this time, if the identified reserved bit is a first value, the communication mode can be determined as a next-generation wireless LAN mode, and if the identified reserved bit is a second value, the communication mode can be determined as a VHT mode. For example, if the identified reserved bit is 0, it can be determined as a next-generation wireless LAN mode, and if the identified reserved bit is 1, it can be determined as a VHT mode.

[0129] FIG. 20 is another example illustrating a communication method of a next-generation wireless LAN frame according to one embodiment.

[0130] Figure 20 illustrates a method for transmitting NGW (Type-4a) and NGW (Type-4b) frames.

[0131] In step (2010), the transmitter can generate a signal field of a next-generation wireless LAN frame with the same length as the signal field of an HT frame. In the case of next-generation wireless LAN mode, a predetermined reserved bit can be input as the first value, and in the case of HT mode, a predetermined reserved bit can be input as the second value. Additionally, the signal field of a next-generation wireless LAN frame can be generated differently from the signal field structure of an HT frame.

[0132] In step (2020), the transmitter can input a reserved bit of the signal field structure of the HT frame as the first value.

[0133] In step (2030), the transmitter can modulate the first symbol of NGW-SIG-A of the next-generation wireless LAN frame into Q-BPSK, and in step (2040), the transmitter can modulate the second symbol of NGW-SIG-A of the next-generation wireless LAN frame into Q-BPSK.

[0134] FIG. 21 is a diagram illustrating a communication method of a next-generation wireless LAN frame according to one embodiment.

[0135] FIG. 21 illustrates a method for receiving NGW (Type-4a) and NGW (Type-4b) frames, wherein in step (2110), the receiver can receive wireless LAN frames.

[0136] In step (2120), the receiver can check the reserved bits of the signal field structure of the HT frame among the wireless LAN frames.

[0137] In step (2130), the receiver can identify the communication mode of the wireless LAN frame according to the identified reserved bit. If the identified reserved bit is a first value, the communication mode can be determined as a next-generation wireless LAN mode, and if the identified reserved bit is a second value, the communication mode can be determined as an HT mode.

[0138] A communication device for next-generation wireless LAN frames according to one embodiment can transmit NGW frames capable of high efficiency and high performance identification while maintaining compatibility with IEEE 802.11a / n / ac.

[0139] Figure 22 is a diagram showing the physical layer structure of IEEE 802.11.

[0140] The physical layer structure of IEEE 802.11 may consist of the PLME (Physical Layer Management Entity), PLCP (Physical Layer Convergence Entity) sublayer, and PMD (Physical Medium Dependent) sublayer. The PLME acts as an interface between the MLME (MAC Layer Management Entity) and the physical layer, providing management functions for the physical layer. The PLCP sublayer acts between the MAC sublayer and the PMD sublayer; depending on signals generated by the control of the MAC layer, it can transmit MPDUs (MAC Protocol Data Units) received from the MAC sublayer or transmit frames coming from the PMD sublayer to the MAC sublayer. As a sublayer of the PLCP, the PMD sublayer supports the physical layer to enable transmission and reception between two terminals over the wireless medium. The MPDU transmitted by the MAC sublayer is called a PSDU (Physical Service Data Unit) by the PLCP sublayer. In this case, an A-MPDU, which is an aggregation of multiple MPDUs, may be transmitted.

[0141] The PLCP sublayer may append fields containing information required by the physical layer transceiver during the process of receiving the PSDU from the MAC sublayer and transmitting it to the PMD sublayer. In this case, the added fields may include a PLCP preamble, a PLCP header, and tail bits to initialize the convolution encoder to the PSDU. The PLCP preamble may consist of a periodic and repetitive sequence to enable the receiver to synchronize, control gain, or determine channel conditions in order to successfully restore the PSDU. The PLCP header may contain information necessary to restore the PSDU. For example, the PLCP header may include packet length, bandwidth, MCS, and the technology used for transmission. The data field may include a service field containing an initialization sequence to initialize the scrambler, and an encoded sequence with tail bits appended. The data field may be modulated and encoded according to the transmission type included in the PLCP header and transmitted. The PLCP sublayer of the transmitting side generates a PPDU and transmits it through the PMD sublayer, and the receiving side receives the PPDU, performs synchronization and gain control using the PLCP preamble, obtains channel state information, and can recover the packet by obtaining the information necessary for packet recovery through the PLCP header.

[0142] The IEEE 802.11ac standard supports the 20MHz or 40MHz bandwidth modes supported by the IEEE 802.11n standard, as well as an 80MHz bandwidth. It also enables transmission using two non-contiguous 80MHz bands simultaneously (non-contiguous 160MHz) or continuous 160MHz bandwidth signal transmission (contiguous 160MHz). An AP supporting the IEEE 802.11ac standard can transmit packets simultaneously to at least one terminal using MU-MIMO (Multi-user MIMO) transmission technology. In the Basic Service Set of a wireless LAN, an AP can simultaneously transmit data separated into different spatial streams to groups containing at least one of the multiple terminals associated with it. Additionally, an AP can transmit data to only one terminal using the SU-MIMO (Single-user MIMO) method. If beamforming technology is supported between an AP and a terminal within a network, it is possible to transmit signals with high gain to a single terminal or group of terminals targeting a specific objective. To support MU-MIMO transmission, a Group ID is assigned to the terminal group, and the AP transmits a Group ID Management Frame to assign and distribute these IDs. A single terminal can be assigned multiple Group IDs. The features supported by wireless LAN terminals or APs may vary depending on the vendor implementing the system and manufacturing the chips. Standards specify optional implementations in addition to mandatory ones, and the supported features may differ depending on the version of the standard implemented.For example, convolutional encoding technology is a mandatory implementation, but LDPC (Low Density Parity Check) technology is an optional implementation, and beamforming, MU-MIMO, and 160 MHz bandwidth support are optional implementations.

[0143] FIG. 23 is a diagram showing the structure of a communication system of a next-generation wireless LAN frame according to one embodiment.

[0144] The wireless communication device of the present invention comprises a transmitting and receiving antenna, a front-end module (FEM), a transmitter, a receiver, an analog-to-digital converter (ADC), a digital-to-analog converter (DAC), a baseband processor, a host interface, a radio interface, a processor, memory, and an input / output interface. Signals may be transmitted and received through one or more antennas. The front-end module is responsible for the interface between the transmitting and receiving antenna and the RF transceiver. The front-end module may include various external components not included in the RF transceiver, or components for performance enhancement and functional expansion. For example, it may include an external transmitting power amplifier, an external receiving low-noise amplifier, a switch, etc. The transmitter performs the function of modulating and transmitting packets to be transmitted, and the receiver performs the function of demodulating received packets. The analog-to-digital converter and the digital-to-analog converter convert the signal format between analog signals and digital signals. The baseband processor performs functions such as generating frames according to the transmission frame format or extracting information from received frames, encoding and decoding, and compensating for signals distorted by channels or analog components. The radio interface serves as an interface between the wireless communication modem and the host. The processor can be configured to generate and transmit PPDU formats, and can be configured to receive transmitted PPDUs, interpret field information from the received packets to obtain control information, and use this information to recover data. The processor or transceiver may include an ASIC (Application Specific Integrated Circuit), logic circuits, or data processing units.Memory may include ROM (Read Only Memory), RAM (Read Access Memory), flash memory, memory cards, and storage devices. Input devices may be keyboards, keypads, microphones, cameras, etc., and output devices may be display means, speakers, etc. When the embodiments described above in the specification of the present invention are implemented in software or hardware, the processes and functions that perform the above-described functions may be implemented as modules. These modules may be implemented or executed in the form of chips, logic circuits, data processing devices, or processors. Explanation of the symbols

[0145] 210, 220: NGW Frame

Claims

Claim 1 A method for transmitting a Physical Layer Protocol Data Unit (PPDU) in a wireless local area network (WLAN), wherein the PPDU comprises a first field and a second field following the first field, and the second field comprises a first symbol and a second symbol, and the method comprises the step of transmitting the first field in a first modulation manner; and the step of transmitting the first symbol and the second symbol of the second field in the first modulation manner, wherein the version of the PPDU is indicated using a 3-bit PHY Version Identifier bit value included in the second field. Claim 2 In claim 1, the PPDU transmission method, wherein the first modulation method is a BPSK (binary phase-shift keying) method. Claim 3 A PPDU transmission method according to claim 1, wherein the first symbol of the second field corresponds to the NGW-SIG-A field. Claim 4 A PPDU transmission method according to paragraph 3, wherein the PPDU includes an L-SIG (Legacy-Signal) field prior to the first symbol of the second field. Claim 5 A device for transmitting a Physical Layer Protocol Data Unit (PPDU) in a Wireless Local Area Network (WLAN), comprising a transceiver and a processor, wherein the processor transmits the first field in a first modulation manner and transmits the first symbol of the second field and the second symbol in the first modulation manner, the PPDU includes the first field and the second field following the first field, the second field includes the first symbol and the second symbol, and the version of the PPDU is indicated using a 3-bit PHY Version Identifier bit value included in the second field. Claim 6 In paragraph 5, the device wherein the first modulation method is a BPSK (binary phase-shift keying) method. Claim 7 In paragraph 5, the device in which the first symbol of the second field corresponds to the NGW-SIG-A field. Claim 8 In claim 7, the above PPDU is a device comprising an L-SIG (Legacy-Signal) field prior to the first symbol of the second field. Claim 9 delete Claim 10 delete Claim 11 delete Claim 12 delete

Images