Signal identification method and communication device

Abstract

To solve the problem that frame overlap in signal transmission processing causes a receiving end device to be unable to accurately synchronize to a target frame, resulting in data packet loss, a signal identification method and a communication apparatus are provided, which can be applied to systems such as UWB-based wireless personal area network systems, Wi-Fi systems, and detection systems. The method includes: a first device performs channel estimation based on an L-LTF sequence corresponding to a received signal frame to obtain a first channel estimate, and determines whether the L-LTF sequence corresponding to the signal frame is a target L-LTF sequence based on the first channel estimate and mark information of N subcarrier elements, where the first channel estimate includes channel estimates corresponding to M subcarrier elements in the L-LTF sequence corresponding to the signal frame, and the mark information of the N subcarrier elements includes sequence numbers of the N subcarrier elements and amplitude and / or phase change values ​​corresponding to the N subcarrier elements, where M and N are positive integers, M>1, 1≦N≦M.

Description

[Technical Field]

[0001] The present application relates to the field of communications, and in particular to a signal identification method and a communications device. [Background technology]

[0002] This application claims priority to Chinese Patent Application No. 202210950021.4, entitled "SIGNAL IDENTIFICATION METHOD AND COMMUNICATION APPARATUS," filed with the State Intellectual Property Office of China on August 9, 2022, which is incorporated herein by reference in its entirety.

[0003] In wireless fidelity (Wi-Fi) systems, data transmission is completed based on the carrier sense multiple access with collision avoidance (CSMA / CA) protocol, and a listen-before-talk (LBT) mechanism is introduced to implement channel monitoring. In particular, before each data transmission, a node must first monitor whether the channel is idle. If the channel is not idle, the node will not send data. A node can only send data when it determines that the channel is idle, so that data being transmitted by another node cannot be interrupted.

[0004] Channel idle detection can be implemented in two ways: one is energy detection (ED), which performs energy evaluation on the received signal, and if the energy value is greater than the ED threshold, it indicates that the channel is occupied by a user; the other is carrier sense (CS), which performs correlation operation by using a known sequence and the preamble sequence of the radio frame physical layer header of the received signal, and if there is correlation, a threshold lower than the ED threshold is used to determine whether the channel is idle; if the threshold exceeds the CS threshold, it indicates that the channel is occupied by a user; or if there is no correlation, ED is used to determine whether the channel is idle.

[0005] However, when the above channel detection mechanism with random backoff feature is used between intra-frequency cells and / or within the same cell, if a transmitting end device cannot find a signal sent by another transmitting end device through detection, there will be a channel busy / idle false determination. Therefore, there may be two transmitting end devices sending Wi-Fi frames on the air interface, which causes a target frame to overlap with another non-target frame. However, the receiving end device cannot guarantee that the target frame that overlaps with the non-target frame will be analyzed, resulting in data packet loss. Summary of the Invention

[0006] The present application provides a signal identification method and a communication device, so that the problem that frame duplication in signal transmission processing causes data packet loss because the receiving end device cannot accurately synchronize with the target frame can be solved.

[0007] To achieve the above objectives, the present application uses the following technical solutions:

[0008] According to a first aspect, a signal identification method is provided. The method can be implemented by a first device, or by a component of the first device, such as a processor, chip, or chip system of the first device, or by a logic module or software that can implement all or some of the functions of the first device. For the purpose of explanation, the following uses an example in which the method is implemented by the first device. The signal identification method includes: A first device receives a signal frame, and the first device performs channel estimation based on a legacy long training field (L-LTF) sequence corresponding to the signal frame to obtain a first channel estimate, where the first channel estimate includes channel estimates corresponding to M subcarrier elements in the L-LTF sequence corresponding to the signal frame, and the first device determines whether the L-LTF sequence corresponding to the signal frame is a target L-LTF sequence based on the first channel estimate and mark information of the N subcarrier elements, where the mark information of the N subcarrier elements includes sequence numbers of the N subcarrier elements and amplitude and / or phase change values ​​corresponding to the N subcarrier elements, where M and N are positive integers, M>1, 1≦N≦M.

[0009] Based on the signal identification method according to the first aspect, a first device can identify the L-LTF sequence corresponding to a currently received signal frame by using a channel estimate of the L-LTF sequence corresponding to the currently received signal frame and mark information of marked subcarrier elements in the target L-LTF sequence. The first device can determine whether the current L-LTF sequence is a target L-LTF sequence marked in a specific marking scheme, thereby more quickly or earlier identifying whether the current signal frame is a target frame. In the event of signal overlap, reception of non-target frames can be terminated in time and reception of the target frame can be resumed in advance, which reduces signal packet loss rates and improves signal reception reliability. Furthermore, a more reliable channel busy / idle determination can also be made based on whether the current signal frame is a target frame. In this way, signals can be sent in time, thereby improving spectrum utilization.

[0010] In a possible design solution, the first device's determining whether an L-LTF sequence corresponding to a signal frame is a target L-LTF sequence based on a first channel estimate and mark information of N subcarrier elements may include: the first device determining a first subcarrier element and a second subcarrier element based on sequence numbers of the N subcarrier elements, where the first subcarrier element is a subcarrier element whose subcarrier element sequence number corresponds to the sequence number of the N subcarrier elements in the L-LTF sequence corresponding to the signal frame, and the second subcarrier element is a subcarrier element whose subcarrier element sequence number is adjacent to the sequence number of the N subcarrier elements in the L-LTF sequence corresponding to the signal frame, and the first device determining whether the L-LTF sequence corresponding to the signal frame is a target L-LTF sequence based on a channel estimate corresponding to the first subcarrier element, a channel estimate corresponding to the second subcarrier element, and amplitude and / or phase change values ​​corresponding to the N subcarrier elements in the first channel estimate. In this way, the first device can identify the L-LTF sequence by using, based on the Wi-Fi channel characteristics, a channel estimate of a subcarrier element (second subcarrier element) whose subcarrier element sequence number is adjacent to the sequence number of the N subcarrier elements and a channel estimate of an unmarked subcarrier element (first subcarrier element) whose subcarrier element sequence number corresponds to the sequence number of the N subcarrier elements, and thus it can be determined whether the current L-LTF sequence is a target L-LTF sequence marked with a particular marking scheme, and whether the current signal frame is a target frame can be identified more quickly or earlier.

[0011] In a possible design solution, the first device's determining whether an L-LTF sequence corresponding to a signal frame is a target L-LTF sequence based on a channel estimate corresponding to a first subcarrier element, a channel estimate corresponding to a second subcarrier element, and amplitude and / or phase change values ​​corresponding to N subcarrier elements in the first channel estimate may include: the first device determines a second channel estimate based on the channel estimate corresponding to the first subcarrier element, a channel estimate corresponding to the second subcarrier element, and amplitude and / or phase change values ​​corresponding to the N subcarrier elements, and when an absolute value of the second channel estimate is smaller than a first threshold, the first device determines that the L-LTF sequence corresponding to the signal frame is the target L-LTF sequence, or when the absolute value of the second channel estimate is equal to or greater than the first threshold, the first device determines that the L-LTF sequence corresponding to the signal frame is not the target L-LTF sequence.

[0012] The second channel estimate is obtained by the first relation

[0013]

number

[0014] When the sequence number of the i-th subcarrier element in the second subcarrier element is different from the sequence numbers of the subcarrier elements in the N subcarrier elements, F_f 12 (i)=f 12 (i) or the sequence number of the i-th subcarrier element in the second subcarrier element is the same as the sequence number of the subcarrier element in the N subcarrier elements;

[0015]

number

[0016] where f2 is the second channel estimate and f 11 (i) is the channel estimate corresponding to the i-th subcarrier element in the first subcarrier element, and T color (i) is the amplitude and / or phase change value corresponding to the i-th subcarrier element among the N subcarrier elements, and f 12 (i) is the channel estimate corresponding to the i-th subcarrier element in the second subcarrier element, and T color (·) is the amplitude and / or phase change value corresponding to a subcarrier element in the N subcarrier elements whose sequence number is the same as the sequence number of the i-th subcarrier element in the second subcarrier elements, where the sequence number of the i-th subcarrier element in the first subcarrier elements is the same as the sequence number of the i-th subcarrier element in the N subcarrier elements, and the i-th subcarrier element in the second subcarrier elements is the subcarrier element whose sequence number is adjacent to the sequence number of the i-th subcarrier element in the N subcarrier elements, where i is a positive integer and 1≦i≦N. In this way, the first device identifies the L-LTF sequence by unmarking the channel estimate corresponding to the first subcarrier element, performing a negation process, and then summing the channel estimate corresponding to the second subcarrier element. This method is simple, and in scenarios where the channel condition is good or the noise is small, the identification of the L-LTF sequence can be completed quickly, thereby improving the identification rate.

[0017] In another possible design solution, the first device's determining whether an L-LTF sequence corresponding to a signal frame is a target L-LTF sequence based on a channel estimate corresponding to a first subcarrier element, a channel estimate corresponding to a second subcarrier element, and amplitude and / or phase change values ​​corresponding to N subcarrier elements in the first channel estimate may include: the first device determines a second channel estimate and a third channel estimate based on the channel estimate corresponding to the first subcarrier element, a channel estimate corresponding to the second subcarrier element, and amplitude and / or phase change values ​​corresponding to the N subcarrier elements, and the first device determines whether the L-LTF sequence corresponding to the signal frame is a target L-LTF sequence based on the second channel estimate and the third channel estimate.

[0018] The second channel estimate is calculated using the second relationship

[0019]

number

[0020] and the third channel estimate satisfies the third relationship

[0021]

number

[0022] When the sequence number of the i-th subcarrier element in the second subcarrier element is different from the sequence numbers of the subcarrier elements in the N subcarrier elements, F_f 12 (i)=f 12 (i) or the sequence number of the i-th subcarrier element in the second subcarrier element is the same as the sequence number of the subcarrier element in the N subcarrier elements;

[0023]

number

[0024] where f2 is the second channel estimate, f3 is the third channel estimate, and f 11 (i) is the channel estimate corresponding to the i-th subcarrier element in the first subcarrier element, and T color (i) is the amplitude and / or phase change value corresponding to the i-th subcarrier element among the N subcarrier elements, and f 12 (i) is the channel estimate corresponding to the i-th subcarrier element in the second subcarrier element, and T color where (·) is the amplitude and / or phase change value corresponding to a subcarrier element in the N subcarrier elements whose sequence number is the same as the i-th subcarrier element in the second subcarrier elements, where the sequence number of the i-th subcarrier element in the first subcarrier elements is the same as the i-th subcarrier element in the N subcarrier elements, and the i-th subcarrier element in the second subcarrier elements is the subcarrier element whose sequence number is adjacent to the i-th subcarrier element in the N subcarrier elements, where i is a positive integer and 1≦i≦N. In this way, based on the identification based on the second channel estimate, the first device may further determine whether the sum of the channel estimate obtained after the channel estimate corresponding to the first subcarrier element is demarked and the channel estimate corresponding to the second subcarrier element is the sum of the amplitudes in the same direction. Identification by combining the second channel estimate and the third channel estimate can improve the identification accuracy. In scenarios with poor channel conditions or high noise, L-LTF sequence identification may also be implemented, thereby further improving signal identification reliability.

[0025] In a possible design solution, the first device's determining whether an L-LTF sequence corresponding to a signal frame is a target L-LTF sequence based on the second channel estimate and the third channel estimate may include: determining that the L-LTF sequence corresponding to the signal frame is the target L-LTF sequence when the ratio between the absolute value of the second channel estimate and the absolute value of the third channel estimate is smaller than a second threshold; or determining that the L-LTF sequence corresponding to the signal frame is not the target L-LTF sequence when the ratio between the absolute value of the second channel estimate and the absolute value of the third channel estimate is equal to or greater than the second threshold. In this way, the first device may identify the L-LTF sequence based on the ratio between the absolute value of the second channel estimate and the absolute value of the third channel estimate. By ensuring the reliability of signal identification, the identification method may be simplified and the signal identification rate may be improved.

[0026] According to a second aspect, a signal identification method is provided. The method may be performed by a second device, or may be performed by a component of the second device, such as a processor, chip, or chip system of the second device, or may be performed by a logic module or software that can implement all or some of the functions of the second device. For the purpose of explanation, the following uses an example in which the method is performed by the second device. The signal identification method includes: the second device marks the amplitude and / or phase of N subcarrier elements in a legacy long training field (L-LTF) sequence corresponding to a signal frame, where the L-LTF sequence corresponding to the signal frame includes M subcarrier elements, M and N are positive integers, M>1, 1≦N≦M, and the second device sends the signal frame to the first device.

[0027] According to the signal identification method of the second aspect, the second device may mark the L-LTF sequence by implementing specific amplitude and / or phase changes on specific subcarrier elements in the L-LTF sequence so that the L-LTF sequence having a specific marking scheme can be used to form a signal frame for transmitting service data. This can ensure that the peak-to-average power ratio and fine frequency offset estimation of the signal are essentially unaffected, and can also improve the degree and rate of signal identification.

[0028] In a possible design solution, when the N subcarrier elements include subcarriers with consecutive sequence numbers, the amplitude and / or phase change values ​​of the subcarrier elements with adjacent sequence numbers are different. Thus, when the sequence numbers of the subcarrier elements selected for marking are consecutive, the subcarrier elements with adjacent sequence numbers need to be marked in different ways to improve signal identification accuracy.

[0029] According to a third aspect, there is provided a communications device, the communications device including a processing module and a transceiver module. The transceiver module is configured to receive a signal frame, the processing module is configured to perform channel estimation based on a legacy long training field (L-LTF) sequence corresponding to the signal frame to obtain a first channel estimate, where the first channel estimate includes channel estimates corresponding to M subcarrier elements in the L-LTF sequence corresponding to the signal frame, and the processing module is further configured to determine whether the L-LTF sequence corresponding to the signal frame is a target L-LTF sequence based on the first channel estimate and mark information of the N subcarrier elements, where the mark information of the N subcarrier elements includes sequence numbers of the N subcarrier elements and amplitude and / or phase change values ​​corresponding to the N subcarrier elements, where M and N are positive integers, M>1, 1≦N≦M.

[0030] In a possible design solution, the processing module being further configured to determine whether an L-LTF sequence corresponding to a signal frame is a target L-LTF sequence based on a first channel estimate and mark information of the N subcarrier elements may include: the processing module being configured to determine a first subcarrier element and a second subcarrier element based on sequence numbers of the N subcarrier elements, where the first subcarrier element is a subcarrier element whose subcarrier element sequence number corresponds to the sequence number of the N subcarrier elements in the L-LTF sequence corresponding to the signal frame, and the second subcarrier element is a subcarrier element whose subcarrier element sequence number is adjacent to the sequence number of the N subcarrier elements in the L-LTF sequence corresponding to the signal frame, and the processing module being further configured to determine whether the L-LTF sequence corresponding to the signal frame is a target L-LTF sequence based on a channel estimate corresponding to the first subcarrier element, a channel estimate corresponding to the second subcarrier element, and amplitude and / or phase change values ​​corresponding to the N subcarrier elements in the first channel estimate.

[0031] In a possible design solution, the processing module being further configured to determine whether an L-LTF sequence corresponding to a signal frame is a target L-LTF sequence based on a channel estimate corresponding to a first subcarrier element, a channel estimate corresponding to a second subcarrier element, and amplitude and / or phase change values ​​corresponding to N subcarrier elements in the first channel estimate includes: the processing module is configured to determine a second channel estimate based on a channel estimate corresponding to the first subcarrier element, a channel estimate corresponding to the second subcarrier element, and amplitude and / or phase change values ​​corresponding to the N subcarrier elements, and the processing module is further configured to determine that the L-LTF sequence corresponding to the signal frame is the target L-LTF sequence when an absolute value of the second channel estimate is smaller than a first threshold, or the processing module is further configured to determine that the L-LTF sequence corresponding to the signal frame is not the target L-LTF sequence when the absolute value of the second channel estimate is equal to or greater than the first threshold.

[0032] The second channel estimate is obtained by the first relation

[0033]

number

[0034] When the sequence number of the i-th subcarrier element in the second subcarrier element is different from the sequence numbers of the subcarrier elements in the N subcarrier elements, F_f 12 (i)=f 12 (i) or the sequence number of the i-th subcarrier element in the second subcarrier element is the same as the sequence number of the subcarrier element in the N subcarrier elements;

[0035]

number

[0036] where f2 is the second channel estimate and f 11 (i) is the channel estimate corresponding to the i-th subcarrier element in the first subcarrier element, and T color (i) is the amplitude and / or phase change value corresponding to the i-th subcarrier element among the N subcarrier elements, and f 12 (i) is the channel estimate corresponding to the i-th subcarrier element in the second subcarrier element, and T color (·) is an amplitude and / or phase change value corresponding to a subcarrier element in the N subcarrier elements whose sequence number is the same as the sequence number of the i-th subcarrier element in the second subcarrier elements, the sequence number of the i-th subcarrier element in the first subcarrier elements is the same as the sequence number of the i-th subcarrier element in the N subcarrier elements, and the i-th subcarrier element in the second subcarrier elements is a subcarrier element whose sequence number is adjacent to the sequence number of the i-th subcarrier element in the N subcarrier elements, where i is a positive integer and 1≦i≦N.

[0037] In another possible design solution, the processing module being further configured to determine whether the L-LTF sequence corresponding to the signal frame is a target L-LTF sequence based on a channel estimate corresponding to the first subcarrier element, a channel estimate corresponding to the second subcarrier element, and amplitude and / or phase change values ​​corresponding to the N subcarrier elements in the first channel estimate may include: the processing module is configured to determine a second channel estimate and a third channel estimate based on the channel estimate corresponding to the first subcarrier element, a channel estimate corresponding to the second subcarrier element, and amplitude and / or phase change values ​​corresponding to the N subcarrier elements, and the processing module is further configured to determine whether the L-LTF sequence corresponding to the signal frame is a target L-LTF sequence based on the second channel estimate and the third channel estimate.

[0038] The second channel estimate is calculated using the second relationship

[0039]

number

[0040] and the third channel estimate satisfies the third relationship

[0041]

number

[0042] When the sequence number of the i-th subcarrier element in the second subcarrier element is different from the sequence numbers of the subcarrier elements in the N subcarrier elements, F_f 12 (i)=f 12 (i) or the sequence number of the i-th subcarrier element in the second subcarrier element is the same as the sequence number of the subcarrier element in the N subcarrier elements;

[0043]

number

[0044] where f2 is the second channel estimate, f3 is the third channel estimate, and f 11 (i) is the channel estimate corresponding to the i-th subcarrier element in the first subcarrier element, and T color (i) is the amplitude and / or phase change value corresponding to the i-th subcarrier element among the N subcarrier elements, and f 12 (i) is the channel estimate corresponding to the i-th subcarrier element in the second subcarrier element, and T color (·) is an amplitude and / or phase change value corresponding to a subcarrier element in the N subcarrier elements whose sequence number is the same as the sequence number of the i-th subcarrier element in the second subcarrier elements, the sequence number of the i-th subcarrier element in the first subcarrier elements is the same as the sequence number of the i-th subcarrier element in the N subcarrier elements, and the i-th subcarrier element in the second subcarrier elements is a subcarrier element whose sequence number is adjacent to the sequence number of the i-th subcarrier element in the N subcarrier elements, where i is a positive integer and 1≦i≦N.

[0045] In a possible design solution, the processing module being further configured to determine whether the L-LTF sequence corresponding to the signal frame is a target L-LTF sequence based on the second channel estimate and the third channel estimate may include: the processing module being configured to determine that the L-LTF sequence corresponding to the signal frame is the target L-LTF sequence when a ratio between the absolute value of the second channel estimate and the absolute value of the third channel estimate is smaller than a second threshold, or the processing module being configured to determine that the L-LTF sequence corresponding to the signal frame is not the target L-LTF sequence when the ratio between the absolute value of the second channel estimate and the absolute value of the third channel estimate is greater than or equal to the second threshold.

[0046] Optionally, the transceiver module may include a receiving module and a sending module, the sending module configured to implement a sending function of the communication device according to the third aspect, and the receiving module configured to implement a receiving function of the communication device according to the third aspect.

[0047] Optionally, the communication device according to the third aspect may further include a storage module for storing a program or instruction, and when the processing module executes the program or instruction, the communication device according to the third aspect may be enabled to perform the method according to the first aspect.

[0048] It should be noted that the communication device according to the third aspect may be a terminal device or a network device, or may be a chip (system) or another part or component that may be disposed in a terminal device or a network device, or may be a device that includes a terminal device or a network device, which is not limited in this application.

[0049] Furthermore, for the technical effects of the communication device according to the third aspect, please refer to the technical effects of the method according to the first aspect, and the details will not be described again here.

[0050] According to a fourth aspect, there is provided a communications apparatus, the communications apparatus including: a processing module and a transceiver module; the processing module is configured to mark amplitude and / or phase of N subcarrier elements in a legacy long training field (L-LTF) sequence corresponding to a signal frame, where the L-LTF sequence corresponding to the signal frame includes M subcarrier elements, M and N are positive integers, M>1, 1≦N≦M; and the transceiver module is configured to send the signal frame to a first device.

[0051] In a possible design solution, when the N subcarrier elements include subcarriers with consecutive sequence numbers, the amplitude and phase change values ​​of the subcarrier elements with adjacent sequence numbers are different.

[0052] Optionally, the transceiver module may include a receiving module and a sending module, the sending module configured to implement a sending function of the communication device according to the fourth aspect, and the receiving module configured to implement a receiving function of the communication device according to the fourth aspect.

[0053] Optionally, the communication device according to the fourth aspect may further include a storage module for storing a program or instruction, and when the processing module executes the program or instruction, the communication device according to the fourth aspect may be enabled to perform the method according to the second aspect.

[0054] It should be noted that the communication device according to the fourth aspect may be a terminal device or a network device, or may be a chip (system) or another part or component that may be disposed in a terminal device or a network device, or may be a device that includes a terminal device or a network device, which is not limited in this application.

[0055] Furthermore, for the technical effects of the communication device according to the fourth aspect, please refer to the technical effects of the method according to the second aspect, and the details will not be described again here.

[0056] According to a fifth aspect, there is provided a communications device, the communications device including a processor coupled to a memory, the processor configured to execute a computer program stored in the memory, such that the communications device performs a method according to any one of the possible implementations of the first and second aspects.

[0057] In a possible design solution, the communication device according to the fifth aspect may further include a transceiver. The transceiver may be a transceiver circuit or an interface circuit. The transceiver may be used by the communication device according to the fifth aspect to communicate with another communication device.

[0058] In the present application, the communication apparatus according to the fifth aspect may be a first device according to the first aspect or a second device according to the second aspect, or a chip (system) or another part or component that may be disposed in the first device or the second device, or an apparatus including the first device or the second device.

[0059] Furthermore, for the technical effects of the communication device according to the fifth aspect, please refer to the technical effects of the method according to any one of the possible implementations of the first aspect and the second aspect, and the details will not be described again here.

[0060] According to a sixth aspect, there is provided a communication system including a first device and a second device, the first device configured to implement the signal identification method according to the first aspect, and the second device configured to implement the signal identification method according to the second aspect.

[0061] According to a seventh aspect, there is provided a computer-readable storage medium, the computer-readable storage medium including a computer program or instructions that, when run on a computer, enables the computer to perform a method according to any one of the possible implementations of the first and second aspects.

[0062] According to an eighth aspect, there is provided a computer program product, the computer program product comprising a computer program or instructions which, when run on a computer, enable the computer to perform a method according to any one of the possible implementations of the first and second aspects. [Brief explanation of the drawings]

[0063] [Figure 1] FIG. 1 is a diagram of a signal collision scenario according to an embodiment of the present application. [Figure 2] FIG. 10 is another diagram of a signal collision scenario according to an embodiment of the present application. [Figure 3] FIG. 10 is yet another diagram of a signal collision scenario according to an embodiment of the present application. [Figure 4] FIG. 1 is a structural diagram of an overlap between a target frame and a non-target frame according to an embodiment of the present application. [Figure 5] 1 is a structural diagram of a Wi-Fi frame in an 802.11ac protocol according to an embodiment of the present application; [Figure 6] FIG. 1 is a structural diagram of distinguishing intra-frequency cells based on BSS color according to an embodiment of the present application; [Figure 7] 1 is a diagram of an architecture of a Wi-Fi communication system according to one embodiment of the present application. [Figure 8] 1 is a schematic flowchart of a signal identification method according to an embodiment of the present application; [Figure 9] 1 is a structural diagram of an OFDM training structure defined in the 802.11 2012 standard protocol according to an embodiment of the present application; [Figure 10] FIG. 2 is a diagram illustrating the change of an unmarked first channel estimate value and a marked first channel estimate value according to an embodiment of the present application; [Figure 11] FIG. 10 is another variation diagram of the unmarked first channel estimate value and the marked first channel estimate value according to an embodiment of the present application; [Figure 12] FIG. 10 is yet another variation diagram of the unmarked first channel estimate value and the marked first channel estimate value according to an embodiment of the present application; [Figure 13] FIG. 10 is yet another variation diagram of the unmarked first channel estimate value and the marked first channel estimate value according to an embodiment of the present application; [Figure 14] FIG. 1 is a diagram of a scenario for differentiating intra-frequency cells according to an embodiment of the present application. [Figure 15] FIG. 1 is a diagram of a scenario for distinguishing different users in the same cell according to an embodiment of the present application. [Figure 16] FIG. 1 is a diagram of a scenario of parallel transmission in intra-frequency cells according to an embodiment of the present application. [Figure 17] FIG. 1 is a structural diagram of signal alternation in intra-frequency cells according to an embodiment of the present application; [Figure 18] FIG. 1 is a structural diagram of parallel transmission of signals in intra-frequency cells according to an embodiment of the present application; [Figure 19] 1 is a diagram of the structure of a communication device according to an embodiment of the present application; [Figure 20] FIG. 1 is a diagram of the structure of another communication device according to an embodiment of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0064] For ease of understanding, the following first describes related art in the embodiments of the present application.

[0065] CSMA / CA requires a node to perform a random backoff process before each transmission. For example, the node randomly generates a random backoff count value based on specified parameters, such as a contention window value. In the random backoff process, the node senses the channel at every 9 microsecond (μs) slot. If the channel is sensed as idle, the node performs one backoff, i.e., decrements the counter by 1. If the channel is sensed as busy, the node pauses the counter until the counter value reaches 0, and then the node can send data.

[0066] CSMA / CA uses two methods of channel idle detection:

[0067] (1) Energy Detection (ED): The receiving end performs energy evaluation on the received signal. If the energy value is greater than the ED threshold, e.g., -62 decibels relative to one milliwatt (dBm) / 20 megahertz (MHz), it indicates that the channel is occupied by a user and the channel is busy. If the energy value is less than the ED threshold, it indicates that the channel is not occupied by a user and the channel is idle.

[0068] (2) Carrier Sense (CS): The receiving end performs a correlation operation by using a known sequence and a fixed sequence of the radio frame physical layer header of the received signal (i.e., preamble), and if there is a correlation, a threshold lower than the ED threshold is used to determine whether the channel is idle, which indicates that the channel is occupied by a user if the threshold is greater than the CS threshold (e.g., -82 dBm / 20 MHz), or if there is no correlation, the ED threshold is used to determine whether the channel is idle.

[0069] However, there is a possibility of signal collision based on the above random backoff detection mechanism, which causes a target frame to overlap with another non-target frame. However, the receiving end device cannot guarantee that the target frame that overlaps with the non-target frame will be analyzed, resulting in data packet loss.

[0070] The following provides an explanation with reference to diagrams of three possible scenarios in which signal collisions occur.

[0071] Scenario 1: As shown in FIG. 1, different channels are deployed interdependently, and intra-frequency cells use the same channel. The intra-frequency cells are separated by two or more other frequency cells. This scenario is typically deployed in a campus office scenario. Channel 1 is used as an example. Access points (AP) 1 and AP 2 use channel 1 to transmit data. The cell where AP 1 is located and the cell where AP 2 is located are intra-frequency cells. In this case, AP 1 needs to transmit downlink services to station (STA) 1, and STA 2 in the cell where AP 2 is located needs to transmit uplink services to AP 2. However, the received signal strength indicator (RSSI) between STA 2 and AP 1 is less than -82 dBm, and STA 2 and AP 1 cannot know who is transmitting signals. In this case, regardless of whether STA 2 and AP 1 perform ED detection or CS detection, both STA 2 and AP 1 determine the channel to be idle, and both STA 2 and AP 1 transmit signals on the air interface. That is, when AP1 sends a signal, STA2 also sends a signal, so intra-frequency parallel interference occurs, signal collision occurs, and data packet loss occurs.

[0072] Scenario 2: As shown in Figure 2, STA1 and STA2 are located in the cell where AP1 is located, and there is an obstacle between STA1 and STA2. If there is a thick wall between STA1 and STA2, the signal energy loss between STA1 and STA2 is large, and STA1 and STA2 cannot know who is sending the signal. In this case, if both STA1 and STA2 send services to AP1, signal collision will also occur. In this case, STA1 and STA2 are hidden nodes of each other, and STA1 and STA2 cannot discover each other through sensing to determine that the channel is idle. Therefore, signal collision occurs, causing data packet loss.

[0073] Scenario 3: As shown in Figure 3, when a data packet of transmitter 2 arrives, transmitter 1 has already sent out a data packet, and transmitter 2 needs to perform channel idle detection before sending out the data packet. However, transmitter 2 has already missed the preamble synchronization header. In this case, when performing channel detection in a distributed inter-frame spacing (DIFS), transmitter 2 does not correlate the preamble and therefore uses an ED threshold (e.g., -62 dBm) to determine whether the channel is idle. When the energy value of the detected signal is less than -62 dBm, the channel is determined to be idle. As a result, there is a false positive, and thus a collision occurs.

[0074] All three scenarios above have a signal collision problem. Signal collision means that two frames received by the receiving end overlap each other, which is sometimes called a message-in-message (MIM). As shown in FIG. 4, the target frame overlaps with an interfering frame (sometimes called a non-target frame), and the signal power of the target frame is much greater than that of the interfering frame. Because the receiving end first synchronizes with the interfering frame, the receiving end has already entered the receiving procedure at time t1, and frame synchronization can only be performed again after the decoding of the entire interfering frame is completed. In this case, the preamble of the target frame has already been missed, and the target frame cannot be locked, which causes data packet loss. The interfering frame is also interfered with by the target frame with high power and cannot be correctly decoded. Therefore, data packet loss is caused.

[0075] Currently, MIM can be solved by using the capture effect. In the process of synchronizing to a non-target frame, signal energy changes can be detected. If it is detected that the signal power change has reached a certain threshold (requiring a power difference between frames to be greater than 10 dB), reception of the currently acquired signal frame can be stopped, and the signal frame is reacquired or resynchronized over the air interface. As shown in FIG. 4, if a receiver machine receives an interfering frame at instant t1 and detects a power change ΔP after Δt, the receiver machine immediately stops receiving the interfering frame and reacquires or resynchronizes the physical layer header of the air interface signal.

[0076] However, when the target frame is acquired by using the capture effect, there are three problems:

[0077] (1) The power difference between the received target and non-target frames must be at least 10 dB, and signals with a power difference between 0 dB and 10 dB cannot be distinguished.

[0078] (2) In the Wi-Fi frame of the 802.11n / ac / ax protocol, there is a high throughput (HT) / very high throughput (VHT) / high efficiency short training field (HE-STF), which is used for second-order automatic gain control (AGC). When a power change occurs in the above subfield, the receiver machine cannot determine the power change, and therefore the power acquisition function cannot be used.

[0079] For example, Figure 5 shows the structure of a Wi-Fi frame in the 802.11ac protocol. As shown in Figure 5, the Wi-Fi frame structure includes an 8 μs legacy short training field (L-STF), an 8 μs legacy long training field (L-LTF), a 4 μs legacy signal field (L-SIG), an 8 μs VHT-SIG-A, a 4 μs VHT-STF, each VHT-LTF with a VHT-LTF symbol length of 4 μs, a 4 μs VHT-SIG-B, and a data portion. When a target frame arrives during the VHT-STF period of a non-target frame, the receiver machine cannot determine the power change. If the frame length is 1 ms and the VHT-STF period is 4 μs, the receiver machine has a 4% chance of being affected. In industrial scenarios, the data packet length is approximately 300 μs, and the packet loss rate is at most 1%. Therefore, a large impact is caused.

[0080] Note that each subfield in a Wi-Fi frame is sometimes referred to as a field.

[0081] (3) Currently, in most receivers, the processing priority of L-SIG, VHT-SIG-A, HT-SIG, and HE-SIG-A in a frame is high, and the reset time after encountering a large signal target frame is long. Therefore, the physical layer synchronization header of the large signal target frame is missed, causing packet loss in the target frame.

[0082] Furthermore, a basic service set (BSS) Color field is introduced in the 802.11ax protocol. In the air interface data transmission process, the BSS Color field is carried in a high efficiency (HE) format in the form of 6 bits in a high efficiency signal field A (HE-SIG-A) in the physical layer header of a physical layer (PHY) protocol data unit (PPDU). BSS Color fields with different values ​​may represent different cells in the intra-frequency cells, and the receiver machine may determine whether the received BSS Color matches the pre-negotiated BSS Color based on the received BSS Color, and may reacquire the Wi-Fi frame from the air interface if the received BSS Color does not match the pre-negotiated BSS Color.

[0083] As shown in FIG. 6, when STA1 receives service data from AP1, the cell in which AP1 is located and the cell in which AP2 is located are intra-frequency cells, and the BSS color field in the signal sent by AP1 is different from the BSS color field in the signal sent by AP2. For example, the BSS color field in the signal frame sent by AP1 is blue, and the BSS color field in the signal frame sent by AP2 is green. When STA1 receives service data from AP1, STA1 can determine whether to continue receiving the signal frame by identifying whether the BSS color field in the received signal frame is blue. If STA1 determines that it should not continue receiving the signal frame, STA1 abandons the currently received signal frame and reacquires the blue BSS color on the air interface.

[0084] However, the BSS color can only be used by terminal devices in the 802.11ax protocol and can be used to distinguish between users in different cells, not between users in the same cell. Furthermore, in the receiver, cells can only be identified after parsing of the HE-SIG-A is completed, and duplicated frames earlier than the HE-SIG-A cannot be identified. Therefore, the MIM problem cannot be avoided by using the BSS color, resulting in data packet loss.

[0085] Therefore, the embodiment of the present application provides a signal identification method to solve the problem of data packet loss caused by frame duplication in signal transmission processing, which prevents the receiving end device from accurately synchronizing with the target frame. The signal identification method is applicable to scenarios with high requirements for the reliability and sensitivity of Wi-Fi signals, such as industrial scenarios such as the control of wireless workshop reconstruction devices, automated guided vehicles (AGVs), steel unmanned aerial vehicles, and vehicle manufacturers' mechanical arm devices; and home game scenarios such as real-time battle mobile phone precision control games and virtual reality (VR) / augmented reality (AR) real-time immersive games. It should be noted that the signal frame in the embodiment of the present application is a Wi-Fi frame.

[0086] The following describes the technical solutions of the present application with reference to the accompanying drawings.

[0087] The technical solutions in the embodiments of the present application may be applied to various communication systems, for example, Wi-Fi systems, vehicle-to-everything (V2X) communication systems, device-to-device (D2D) communication systems, vehicular Internet communication systems, as well as future communication systems, such as fourth-generation (4G) mobile communication systems, such as long-term evolution (LTE) systems, LTE frequency division duplex (FDD) systems, LTE time division duplex (TDD) systems, and worldwide interoperability for microwave access (WiMAX) communication systems, fifth-generation (5G) mobile communication systems, such as new radio (NR) systems, and sixth-generation (6G) mobile communication systems.

[0088] Various aspects, embodiments, or features are presented in this application by describing systems that may include multiple devices, components, modules, etc. It is to be appreciated and understood that each system may include other devices, components, modules, etc. and / or may not include all of the devices, components, modules, etc. discussed with reference to the accompanying drawings. Furthermore, combinations of these solutions may be used.

[0089] Furthermore, in the embodiments of this application, terms such as "example" and "for example" are used to denote providing an example, illustration, or explanation. Any embodiment or design scheme described in this application as an "example" should not be described as preferred or having more advantages over another embodiment or design solution. Rather, the term "example" is used to present a concept in a particular way.

[0090] In embodiments of the present application, sometimes a subscript, e.g., W1, may be mistakenly written in a non-subscript form, e.g., W1. When the difference is not emphasized, the meaning expressed is consistent.

[0091] The network architectures and service scenarios described in the embodiments of the present application are intended to more clearly explain the technical solutions in the embodiments of the present application, and do not constitute limitations on the technical solutions provided in the embodiments of the present application. Those skilled in the art may know that: with the development of network architectures and the emergence of new service scenarios, the technical solutions provided in the embodiments of the present application can also be applied to similar technical problems.

[0092] To facilitate understanding of the embodiments of the present application, the Wi-Fi communication system shown in Figure 7 is first used as an example to describe in detail the communication system to which the embodiments of the present application are applicable. For example, Figure 7 is a diagram of the architecture of a Wi-Fi communication system according to one embodiment of the present application.

[0093] As shown in Figure 7, the Wi-Fi communication system includes one or more network devices, such as network device 1 and network device 2, and one or more terminal devices, such as terminal device 1 and terminal device 2. Communication between the network devices may be implemented, communication between the network devices and the terminal devices may also be implemented, and communication between the terminal devices may also be implemented. Figure 7 shows an example of two network devices and two terminal devices. The number of network devices and the number of terminal devices are not limited in this embodiment of the present application.

[0094] The cell in which network device 1 is located and the cell in which network device 2 is located are intra-frequency cells. In the scenario shown in FIG. 1, network device 1 is AP1, and network device 2 is AP2. The cell in which AP1 is located and the cell in which AP2 is located are intra-frequency cells, and both AP1 and AP2 use channel 1 to send signals. Terminal device 1 and terminal device 2 may be located in the same cell or in different cells. For example, terminal device 1 and terminal device 2 are located in the cell in which AP1 is located, or terminal device 1 is located in the cell in which AP1 is located, and terminal device 2 is located in the cell in which AP2 is located.

[0095] In the Wi-Fi communication system provided in this embodiment of the present application, when one device (including a network device or a terminal device) sends data to another device (including a network device or a terminal device), the device that sends the data is a transmitting end, and the device that receives the data is a receiving end. The receiving end is configured to implement functions such as signal acquisition and processing, and the transmitting end is configured to implement functions such as signal generation and sending.

[0096] In some possible cases, a transmitting end may be used as a receiving end to implement functions such as signal acquisition and processing, and a receiving end may be used as a transmitting end to implement functions such as signal generation and transmission. In other words, one physical device may be a transmitting end, or a receiving end, or both a transmitting end and a receiving end.

[0097] The technical solutions provided in the present application are applicable to wireless local area network (WLAN) scenarios, for example, to Institute of Electrical and Electronics Engineers (IEEE) 802.11 system standards, such as the 802.11a / b / g standard, the 802.11n standard, the 802.11ac standard, the 802.11ax standard, or a next-generation standard of the 802.11ax standard, for example, the 802.11be standard, Wi-Fi 7, or extremely high throughput (EHT), or in another example, the next-generation standard of 802.11be, Wi-Fi 8, or a next-generation standard of Wi-Fi 8.

[0098] The embodiments of the present application are primarily described using an example of a deployed WLAN network, particularly a network using the IEEE 802.11 system standard. Those skilled in the art will readily understand that aspects related to the present application can be extended to other networks using various standards or protocols, such as BLUETOOTH, high performance radio LAN (HIPERLAN) (a wireless standard similar to the IEEE 802.11 standard and primarily used in Europe), wide area networks (WANs), personal area networks (PANs), or other networks now known or developed in the future. Therefore, various aspects provided in the present application are applicable to any suitable wireless network, regardless of the coverage and wireless access protocol used.

[0099] In an embodiment of the present application, the network device is located on the network side of a Wi-Fi communication system and is a device having a wireless transceiver function, or a chip or chip system that can be disposed in the device. The network device includes, but is not limited to, an AP, for example, a home gateway, a router, a server, a switch, or a bridge in a wireless fidelity (Wi-Fi) system, an evolved NodeB (eNB), a radio network controller (RNC), a NodeB (NB), a base station controller (BSC), a base transceiver station (BTS), a home base station (e.g., a home evolved NodeB, HNB), a baseband unit (BBU), a wireless relay node, a wireless backhaul node, a transmission point (transmit reception point, TRP, or transmission point, TP), etc. Alternatively, the network device may be a gNB or a transmission point (TRP or TP) in a 5G system, for example, a new radio (NR) system, or may be one antenna panel or a group of antenna panels (including multiple antenna panels) of a base station in a 5G system, or may be a network node, for example, a baseband unit (BBU) or distributed unit (DU) constituting a gNB or a transmission point, a road side unit (RSU) having base station functionality, etc.

[0100] The terminal device is a terminal that accesses a Wi-Fi communication system and has a wireless transceiver function, or a chip or chip system that can be disposed in a terminal. The terminal device may also be called a non-access point station (non-AP station, non-AP STA), STA, user equipment, access terminal, subscriber unit, subscriber station, mobile station, remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent, or user equipment. The terminal device in the embodiment of the present application may be a mobile phone, a tablet computer (Pad), a computer with a wireless transceiver function, a VR terminal device, an AR terminal device, a wireless terminal in industrial control, a wireless terminal in autonomous driving, a wireless terminal in remote medical care, a wireless terminal in a smart grid, a wireless terminal in transportation safety, a wireless terminal in a smart city, a wireless terminal in a smart home, an in-vehicle terminal, an RSU with a terminal function, etc. The terminal device in this application may alternatively be an on-board module, an on-board assembly, an on-board component, an on-board chip, or an on-board unit that is incorporated into the vehicle as one or more components or units, and the vehicle implements the signal identification method provided in this application using the on-board module, on-board assembly, on-board component, on-board chip, or on-board unit that is incorporated into the vehicle.

[0101] It should be noted that the signal identification method provided in the embodiments of the present application can be applied to any two nodes shown in Figure 7, for example, between a network device and a terminal device, between network devices, and between terminal devices. For specific implementation, please refer to the following method embodiments. Details will not be described again here.

[0102] It should be noted that the solutions in the embodiments of the present application may alternatively be applied to another communication system, and the corresponding names may alternatively be replaced with the names of corresponding functions in another communication system.

[0103] It should be understood that Figure 7 is merely a simplified diagram used as an example for ease of understanding, and the communication system may further include other network devices and / or other terminal devices not depicted in Figure 7.

[0104] The following describes in detail the signal identification method provided in the embodiments of the present application with reference to FIGS.

[0105] For example, Figure 8 is a schematic flowchart of a signal identification method according to one embodiment of the present application. The signal identification method is applicable to communication between any two nodes in Figure 1, Figure 2, or Figure 7.

[0106] As shown in FIG. 8, the signal identification method may include the following steps.

[0107] S801: A second device marks the amplitude and / or phase of N subcarrier elements in an L-LTF sequence corresponding to a signal frame.

[0108] The second device may be any terminal device or any network device shown in Figure 7. The L-LTF sequence corresponding to the signal frame includes M subcarrier elements, the L-LTF sequence is a frequency domain sequence, each signal frame corresponds to two identical L-LTF sequences, M and N are positive integers, M>1, 1≦N≦M.

[0109] In this embodiment of the present application, marking subcarrier elements in an L-LTF sequence may also be referred to as coloring the subcarrier elements, or marking or coloring the L-LTF sequence, and refers to changing the amplitude and / or phase of the subcarrier elements. For example, different devices may select different subcarrier elements in an L-LTF sequence to make the same or different amplitude and / or phase changes, or select the same subcarrier elements to use the same or different amplitude and / or phase changes; that is, the devices may have different marking or coloring schemes for the L-LTF sequence, such that the signal frames sent by the devices correspond to different L-LTF sequences, and the L-LTF sequences may be used to distinguish the signals sent by the devices.

[0110] For example, the second device selects the amplitude and / or phase of N subcarrier elements from the M subcarrier elements for marking, i.e., the second device selects N subcarrier elements, changes the amplitude and / or phase values ​​of the N subcarrier elements, and marks the changed N subcarrier elements to obtain a marked or colored L-LTF sequence. For example, the marking or coloring process of a single subcarrier element is performed using the formula x ltf [m]=T Color [m]*s LTF [m], where: m is the sequence number of the subcarrier element, and x ltf [m] is the value of the mth subcarrier element marked, and T Color [m] is the amplitude and / or phase change value of the mth subcarrier element, and s LTF[m] is the value of the mth unmarked subcarrier element, m is a positive integer, 0≦m≦M−1. The second device performs marking or coloring processing on all subcarrier elements in the entire L-LTF sequence, and the amplitude and / or phase of selected N subcarrier elements are changed, i.e., T Color [m]≠1 and the phase and / or amplitude of the remaining subcarrier elements are unchanged, i.e., T Color It can be seen that [m] = 1. Alternatively, for N marked subcarrier elements in the L-LTF sequence, T Color For [m] ≠ 1 and unmarked subcarrier elements, T Color It can be seen that [m]=1.

[0111] A 20 MHz bandwidth is used as an example. The L-LTF sequence defined in the standard protocol includes 64 subcarrier elements, and the value of each subcarrier element in the sequence is 1, 0, or -1. For example, the following L[1,64] is an unmarked L-LTF sequence assigned to the second device.

[0112] L[1,64]={0,0,0,0,0,0,1,1,-1,-1,1,1,-1,1,-1,1,-1,1,-1,1,1,1,1,1,1,-1,-1,1,1,-1,1,-1,1,-1,1,1,1,1,0,1,-1,-1,1,1,-1,1,-1,1,-1,-1,1,-1,1,-1,1,1,-1,1,1,1,0,0,0,0,0}, and the sequence numbers of the subcarrier elements in the unmarked L-LTF sequence are from 1 to 64. It can be understood that the amount of subcarrier elements in the L-LTF sequence can be determined based on the bandwidth. In this embodiment of the present application, the above unmarked L-LTF sequence, L[1,64], is used for description.

[0113] The amplitude of the seventh subcarrier element, which has a value of 1, is changed, for example, the amplitude is doubled, i.e., T Color If [7]=2, the value of the marked 7th subcarrier element is changed to 2. Alternatively, the phase of the 7th subcarrier element is changed, for example, the phase is rotated by 180°, i.e., T Color [7]=e jπ , then the value of the marked 7th subcarrier element is changed to −1. Alternatively, the amplitude and phase of the 7th subcarrier element are changed, for example, the amplitude is amplified by a factor of 2 and the phase is rotated by 180°, i.e., T Color [7]=2e jπ If so, the value of the marked 7th subcarrier element is changed to −2.

[0114] If possible, the N subcarrier elements may be subcarrier elements with non-consecutive sequence numbers among the M subcarrier elements, for example, subcarrier elements with sequence numbers 8, 21, 23, 28, 32, and 50 in L[1,64], i.e., N=6. In this case, the amplitude and phase changes of the N subcarrier elements may be the same or different, or may be partially the same or partially different, which is not particularly limited in this embodiment of the present application.

[0115] In another possible case, the N subcarrier elements may alternatively include subcarrier elements with adjacent sequence numbers. For example, N=5 and the subcarrier elements may include subcarrier elements with sequence numbers 11, 12, 13, 26, and 51 in L[1,64], or subcarrier elements with sequence numbers 11, 12, 13, 14, and 15 in L[1,64]. In this case, the amplitude and phase change values ​​of two subcarrier elements with adjacent sequence numbers are different. In other words, when the amplitude and phase of two subcarrier elements with adjacent sequence numbers are changed together, the amplitude and phase change values ​​may not be the same, but the two subcarrier elements with adjacent sequence numbers may have the same amplitude but different phases, or different amplitudes but the same phase, to facilitate subsequent identification. For example, the amplitude and phase change values ​​of subcarrier elements with sequence numbers 11 and 12 may be different, and the amplitude and phase change values ​​of subcarrier elements with sequence numbers 12 and 13 may be different, but the amplitude and phase change values ​​of subcarrier elements with sequence numbers 11 and 13 may be the same.

[0116] Note that the second device may also mark subcarrier elements throughout the entire L-LTF sequence, i.e., vary the amplitude and / or phase of M subcarrier elements. In this case, the amplitude and phase change values ​​of two subcarrier elements with adjacent sequence numbers may not be the same. When the channel condition is good, the second device may also mark only one subcarrier element in the L-LTF sequence.

[0117] It can be understood that during practical application, when subcarrier elements are selected for marking, subcarrier elements with a value of 0 should be avoided as much as possible, and it should be ensured that the peak to average power ratio (PAPR) of the signal of the selected subcarrier elements after the marking process is sufficiently small. Furthermore, in extreme cases, the amplitude and phase changes of the subcarrier elements may exceed TColor [m]=0 may be possible.

[0118] Furthermore, the second device performs a frequency domain to time domain transformation on the marked L-LTF sequence and adds a cyclic prefix (CP) to the L-LTF sequence to form an L-LTF in the transmitted signal frame, which includes two identical orthogonal frequency division multiplexing (OFDM) symbols.

[0119] For example, Figure 9 is a structural diagram of the OFDM training structure defined in the 802.11 2012 standard protocol. As shown in Figure 9, the OFDM training structure includes an 8 μs L-STF, an 8 μs L-LTF, a 4 μs signaling field, and a data portion. The L-LTF includes a 1.6 μs CP (i.e., GI2) and two 3.2 μs OFDM symbols (i.e., T1 and T2). T1 and T2 are two repeated signals obtained by performing a frequency-domain to time-domain transformation on the L-LTF sequence. In other words, T1 and T2 are obtained by performing a frequency-domain to time-domain transformation on the same L-LTF sequence twice. It can also be understood that T1 and T2 are obtained by performing a frequency-domain to time-domain transformation on two identical L-LTF sequences. For the formation of separate time-domain waveforms of signal frames, please refer to existing implementation processes. Details will not be described in this embodiment of the present application.

[0120] It can be seen that the L-LTF is used for fine frequency offset estimation and channel estimation. In this embodiment of the present application, after the L-LTF sequence forming the L-LTF is colored or marked, the marked L-LTF sequence undergoes two conversions from the frequency domain to the time domain to form two repeated OFDM symbols, namely, T1 and T2. Therefore, the fine frequency offset estimation process is not affected. Furthermore, when the amount of marked subcarrier elements is not large or the marking scheme is the same, the formed L-LTF has little effect on the PAPR of the signal. Furthermore, when the marked subcarrier elements are selected, the appropriate subcarrier elements can be found through search, and therefore the impact on the PAPR can be reduced by 1 dB to 2 dB.

[0121] It should be noted that for each transmitting end device, the unmarked L-LTF sequence used by the transmitting end device to send service data is fixed, and for the receiving end, the receiving end also stores the unmarked L-LTF sequence of each transmitting end device. Furthermore, the unmarked L-LTF sequences assigned to different transmitting end devices may be the same or different.

[0122] S802: The second device sends a signal frame to the first device. In response, the first device receives a signal frame from the second device.

[0123] The first device may be any terminal device or any network device shown in Figure 7. The signal frame includes an L-LTF obtained by performing a frequency domain to time domain transformation on the marked L-LTF sequence. For the structure of the time domain waveform of the signal frame, please refer to the structure shown in Figure 5 or Figure 9. The details will not be described again here.

[0124] Correspondingly, the first device receives the signal frame. After capturing the signal frame on the air interface, the first device synchronizes with the signal frame and enters the reception procedure. However, the currently synchronized and received signal frame may be a signal frame sent by another device, i.e., the signal frame may not be the signal frame sent by the second device in S802. For example, there is the MIM problem shown in FIG. 4. Therefore, in order to quickly identify whether the current signal frame is the target frame, the first device needs to determine whether the currently received signal frame is the target service sent by the target device, i.e., whether the currently received signal frame is the signal frame sent by the second device. If the currently received signal frame is not the target frame, reception may be stopped in time, and re-acquisition of the target frame may be performed on the air interface. For specific implementation processes, please refer to the following related descriptions in S803 and S804.

[0125] It can be understood that the transmitted signal frame is altered in the transmission process, e.g., signal attenuation, i.e., the received and transmitted signal frames have a power difference, but the information carried in the received and transmitted signal frames is unchanged.

[0126] S803: The first device performs channel estimation based on the L-LTF sequence corresponding to the signal frame to obtain a first channel estimate.

[0127] The first channel estimate includes channel estimates corresponding to M subcarrier elements in the L-LTF sequence corresponding to the currently received signal frame, i.e., M channel estimates corresponding to the M subcarrier elements.

[0128] For example, in the process of receiving a signal frame, the first device parses the L-LTF in the signal frame to obtain the L-LTF sequence in the signal frame, for example, by performing a conversion process from the time domain to the frequency domain. Due to signal attenuation, the value of the subcarrier element in the received L-LTF sequence is different from the value of the subcarrier element in the sent L-LTF sequence. Therefore, the value of a single subcarrier element in the L-LTF sequence obtained by the first device through parsing can be expressed as y ltf [m]=H1[m]*x ltf [m]=H1[m]*T Color [m]*s LTF [m], where: H1[m] is the original channel estimate for the mth subcarrier element, which can be understood as the channel estimate corresponding to the unmarked subcarrier element or the ratio of the received signal to the sent signal.

[0129] It can be understood that before parsing the L-LTF, the first device first parses the L-STF. The L-STF can be used to implement functions such as signal detection, coarse frequency offset estimation, and symbol timing. For specific implementation processes, please refer to existing related descriptions. Details will not be described again here.

[0130] Furthermore, the first device then performs channel estimation by using the L-LTF sequence obtained through parsing to obtain a first channel estimate, where the process of obtaining a channel estimate of an arbitrary subcarrier element in the first channel estimate can be expressed as:

[0131]

number

[0132] This can be implemented by using

[0133] That is, the channel estimate corresponding to an arbitrary subcarrier element (m-th subcarrier element) in the first channel estimate is H2[m]=H1[m]*T Color [m] is.

[0134] It can be seen that if the amplitude and / or phase of a subcarrier element is changed, the same change to the amplitude and / or phase also occurs in the channel estimate corresponding to the subcarrier element, i.e., the channel estimate of the marked subcarrier element in the first channel estimate is the same as the original channel estimate.

[0135] It should be noted that the channel estimate value may be a channel estimate amplitude value, or may be a channel estimate phase value, or may be a channel estimate complex value (including a channel estimate amplitude value and a channel estimate phase value).

[0136] For example, if the second device changes the amplitude of the 28th to 31st subcarrier elements in the L-LTF sequence, the amplitude is amplified by a factor of 2, i.e., T Color

[28] =T Color

[29] =T Color

[30] =T Color

[31] =2, and the first device performs channel estimation on the L-LTF sequence, and the obtained first channel estimate is shown in FIG. 10. The channel estimates of the 28th to 31st subcarrier elements in the L-LTF sequence are also correspondingly changed to twice the original channel estimates. When the original channel estimate amplitude value of the 28th subcarrier element is 0.41501, the marked channel estimate amplitude value is 0.82984. In this case, the channel estimate is the channel estimate amplitude value.

[0137] In another example, if the second device changes the phase of the 28th to 31st subcarrier elements in the L-LTF sequence, for example, the phase is rotated by 180°, i.e., T Color

[28] =TColor

[29] =T Color

[30] =T Color

[31] =e jπ = -1, and the first device performs channel estimation on the L-LTF sequence, and the obtained first channel estimate is shown in Figure 11. The channel estimates of the 28th to 31st subcarrier elements in the L-LTF sequence are also rotated 180° compared with the original channel estimates. If the original channel estimate phase value of the 28th subcarrier element is 68.3825°, the marked channel estimate phase value is -111.6165°. In this case, the channel estimate is the channel estimate phase value.

[0138] Note that for subcarrier elements with a value of 0, the channel estimate corresponding to the subcarrier element is also 0. Therefore, in the first channel estimates shown in Figures 10 and 11, channel estimates with subcarrier elements of 0 are not shown.

[0139] 10 and 11 are used to explain the relationship between the channel estimate and the amplitude and / or phase change of the subcarrier elements. In practical application, when the amplitude and phase of subcarrier elements with consecutive sequence numbers are changed simultaneously, the amplitude and phase change values ​​need to be different. For example, when only the amplitude of the 28th to 31st subcarrier elements is changed, the amplitude change values ​​of the 28th and 29th subcarrier elements, or the 29th and 30th subcarrier elements, or the 30th and 31st subcarrier elements need to be different.

[0140] It can be understood that when the phase and amplitude are varied simultaneously, the correspondingly obtained channel estimate is a channel estimate complex value.

[0141] S804: The first device determines, based on the first channel estimate and the mark information of the N subcarrier elements, whether the L-LTF sequence corresponding to the signal frame is a target L-LTF sequence.

[0142] The mark information of the N subcarrier elements includes sequence numbers of the N subcarrier elements and amplitude and / or phase change values ​​corresponding to the N subcarrier elements, i.e., mark information of the L-LTF sequence marked by the second device. The target L-LTF sequence is the L-LTF sequence corresponding to the signal frame sent by the second device.

[0143] The mark information of the N subcarrier elements may be obtained through pre-negotiation or pre-configuration between the first device and the second device. For example, when the first device is a network device and the second device is a terminal device, or when the first device is a terminal device and the second device is a network device, when the terminal device associates with the network device, the terminal device may add the mark information of the N subcarrier elements to an association frame, or the terminal device may obtain the mark information from a beacon frame transmitted by the network device, or the network device may send the mark information of the N subcarrier elements to the terminal device by using a newly added Wi-Fi 6 trigger frame. The negotiation method of the mark information of the N subcarrier elements is not particularly limited in this embodiment of the present application.

[0144] Based on the Wi-Fi channel characteristics, the channel estimation amplitude values ​​and channel estimation phase values ​​of adjacent subcarrier elements in the unmarked L-LTF sequence are approximately consecutive or approximately equal. As shown in FIG. 12, the channel estimation amplitude value of subcarrier element 50 is 0.71571, and the channel estimation amplitude value of subcarrier element 51 is 0.706, indicating a very small difference between the channel estimation amplitude values ​​of the two subcarrier elements. This is also true for the channel estimation amplitude value of subcarrier element 49 and the channel estimation amplitude value of subcarrier element 50. As also shown in FIG. 13, the channel estimation phase value of subcarrier element 50 is −82.2295°, and the channel estimation phase value of subcarrier element 49 is −80.2438°, indicating a very small difference between the channel estimation phase values ​​of the two subcarrier elements. This is also true for the channel estimation phase value of subcarrier element 50 and the channel estimation phase value of subcarrier element 51. Therefore, the first device can determine an L-LTF sequence corresponding to a signal frame based on the channel estimation values.

[0145] 12 and 13, the channel estimation amplitude value and the channel estimation phase value of at least two subcarrier elements having consecutive sequence numbers are essentially equal. Therefore, in this embodiment of the present application, the subcarrier element whose sequence number is adjacent to the sequence number of the m-th subcarrier element may be a subcarrier element whose channel estimation amplitude value and channel estimation phase value are very small or almost equal to the channel estimation amplitude value and channel estimation phase value of the m-th subcarrier element, and whose sequence number is at least one different from the sequence number of the m-th subcarrier element. For example, the subcarrier element adjacent to subcarrier element 50 may be any subcarrier element between 48 and 52. This is not particularly limited in this embodiment of the present application. It can be understood that the channel estimation amplitude value and the channel estimation phase value of the subcarrier element whose sequence number is one different from the sequence number of the m-th subcarrier element are closest to the channel estimation amplitude value and the channel estimation phase value of the m-th subcarrier element. For ease of explanation, in the following embodiments, the subcarrier element whose sequence number is one difference from the sequence number of the m-th subcarrier element is used as the adjacent subcarrier element for explanation.

[0146] In a possible design solution, when the channel condition is good, the first device may determine, based on the first channel estimate, whether there is an abruptly changed channel estimate in the first channel estimate and determine whether the sequence number of the subcarrier element corresponding to the abruptly changed channel estimate is the same as the sequence number of the N subcarrier elements. If the sequence number of the subcarrier element corresponding to the abruptly changed channel estimate is the same as the sequence number of the N subcarrier elements, the first device may determine that the L-LTF sequence is the target L-LTF sequence and therefore continue receiving the signal frame corresponding to the L-LTF sequence. If the sequence number of the subcarrier element corresponding to the abruptly changed channel estimate is different from the sequence number of the N subcarrier elements, the first device may determine that the L-LTF sequence is not the target L-LTF sequence and therefore immediately stop and terminate reception of the current signal frame, reset all receiving modules, and re-receive the air interface signal until the target frame is received.

[0147] Alternatively, the first device may determine based on whether a channel estimate corresponding to a first subcarrier element has changed abruptly in the first channel estimate, where the first subcarrier element is a subcarrier element whose sequence number corresponds to the sequence number of the N subcarrier elements in an L-LTF sequence corresponding to the signal frame. If the channel estimate corresponding to each subcarrier element in the first subcarrier element has changed abruptly, it may be determined that the L-LTF sequence is the target L-LTF, and the first device may continue receiving the signal frame corresponding to the L-LTF sequence. If the channel estimate corresponding to each subcarrier element in the first subcarrier element has not changed abruptly or has only changed partially, it may be determined that the L-LTF sequence is not the target L-LTF, and the first device immediately stops and terminates reception of the current signal frame, resets all receiving modules, and re-receives air interface signals until the target frame is received.

[0148] For example, the sequence numbers of the N subcarrier elements are 8, 21, 23, 28, 32, and 50, i.e., N=6, and the amplitudes of the six subcarrier elements are amplified by a factor of 2 and the phases are rotated by 180°, i.e., T Color [m]=2e jπ = -2, where m = 8, 21, 23, 28, 32, 50. The first device determines the subcarrier elements with sequence numbers 8, 21, 23, 28, 32, 50 in the L-LTF sequence corresponding to the currently received signal frame as the first subcarrier elements, i.e., the first subcarrier elements are the subcarrier elements with sequence numbers {8, 21, 23, 28, 32, 50}. If the channel estimate value of the first subcarrier element in the L-LTF sequence corresponding to the currently received signal frame is suddenly and drastically changed, as shown in Figures 12 and 13, it can be determined that the L-LTF sequence corresponding to the signal frame is the target L-LTF.

[0149] In another possible design solution, the first device may determine whether the L-LTF sequence corresponding to the signal frame is a target L-LTF sequence by using the following steps 1 and 2.

[0150] Step 1: The first device may determine a first subcarrier element and a second subcarrier element based on sequence numbers of the N subcarrier elements, where the first subcarrier element is a subcarrier element in an L-LTF sequence corresponding to a signal frame, whose subcarrier element sequence number corresponds to the sequence number of the N subcarrier elements, and the second subcarrier element is a subcarrier element in an L-LTF sequence corresponding to the signal frame, whose subcarrier element sequence number is adjacent to the sequence number of the N subcarrier elements.

[0151] For example, the sequence numbers of the N subcarrier elements are 8, 21, 23, 28, 32, and 50, i.e., N=6, and the amplitudes of the six subcarrier elements are amplified by a factor of 2 and the phases are rotated by 180°, i.e., T Color [m]=2e jπ= -2, where m = 8, 21, 23, 28, 32, 50. The first device determines the subcarrier elements having sequence numbers 8, 21, 23, 28, 32, and 50 in the L-LTF sequence corresponding to the currently received signal frame as first subcarrier elements, i.e., the first subcarrier elements are the subcarrier elements having sequence numbers {8, 21, 23, 28, 32, 50}. Furthermore, the first device determines the subcarrier elements adjacent to sequence numbers 8, 21, 23, 28, 32, and 50 in the L-LTF sequence corresponding to the currently received signal frame as second subcarrier elements. The subcarrier elements adjacent to 8, 21, 23, 28, 32, and 50 in the L-LTF sequence corresponding to the currently received signal frame may be the corresponding subcarrier elements having the previous sequence number or the corresponding subcarrier elements having the next sequence number. For example, the second subcarrier elements are subcarrier elements with sequence numbers {7, 20, 22, 27, 31, 49}, or subcarrier elements with sequence numbers {9, 22, 24, 29, 33, 51}, or subcarrier elements with sequence numbers {7, 22, 24, 27, 31, 49}, which is not particularly limited in this embodiment of the present application.

[0152] Step 2: The first device may determine whether the L-LTF sequence corresponding to the signal frame is a target L-LTF sequence based on a channel estimate corresponding to the first subcarrier element, a channel estimate corresponding to the second subcarrier element, and amplitude and / or phase change values ​​corresponding to the N subcarrier elements in the first channel estimate.

[0153] If possible, the first device calculates each channel estimate in the channel estimate corresponding to the first subcarrier element as T Color [m], i.e., perform de-marking or color fading processing on the first subcarrier element based on the amplitude and / or phase change values ​​corresponding to the N subcarrier elements, which can be

[0154]

number

[0155] where m=8, 21, 23, 28, 32, 50. To determine whether the L-LTF sequence corresponding to the signal frame is the target L-LTF sequence, the first device may determine whether V1[m] corresponding to each subcarrier element in the first subcarrier elements is essentially equal to the channel estimate of each subcarrier element in the second subcarrier elements.

[0156] For example, the second subcarrier elements are subcarrier elements with sequence numbers {7, 20, 22, 27, 31, 49}, and the channel estimate of each subcarrier element in the second subcarrier elements is expressed as H2[m±1], where m±1 = 7, 20, 22, 27, 31, 49. The first device compares V1[m] with H2[m±1] to determine whether the L-LTF sequence corresponding to the signal frame is the target L-LTF sequence.

[0157] When V1[8] and H2[7], V1

[21] and H2

[20] , V1

[23] and H2

[22] , V1

[28] and H2

[27] , V1

[32] and H2

[31] , and V1

[50] and H2

[49] are essentially equal or essentially identical, the first device may determine that the L-LTF sequence corresponding to the current signal frame is the target L-LTF sequence.

[0158] When V1[8] and H2[7], V1

[21] and H2

[20] , V1

[23] and H2

[22] , V1

[28] and H2

[27] , V1

[32] and H2

[31] , and V1

[50] and H2

[49] partially match or completely differ, the first device may determine that the L-LTF sequence corresponding to the current signal frame is not the target L-LTF sequence.

[0159] In another possible case, the first device may determine a second channel estimate based on a channel estimate corresponding to the first subcarrier element, a channel estimate corresponding to the second subcarrier element, and amplitude and / or phase change values ​​corresponding to the N subcarrier elements, where the second channel estimate is determined based on a first relationship

[0160]

number

[0161] Meet the following.

[0162] When the absolute value of the second channel estimate is smaller than a first threshold, the first device may determine that the L-LTF sequence corresponding to the signal frame is a target L-LTF sequence; or When the absolute value of the second channel estimate is greater than or equal to the first threshold, the first device may determine that the L-LTF sequence corresponding to the signal frame is not the target L-LTF sequence.

[0163] When the sequence number of the i-th subcarrier element in the second subcarrier element is different from the sequence number of the subcarrier element in the N subcarrier elements, F_f 12 (i)=f 12 (i) or the sequence number of the i-th subcarrier element in the second subcarrier element is the same as the sequence number of the subcarrier element in the N subcarrier elements;

[0164]

number

[0165] where f2 is the second channel estimate and f 11 (i) is the channel estimate corresponding to the i-th subcarrier element in the first subcarrier element, and T color(i) is the amplitude and / or phase change value corresponding to the i-th subcarrier element among the N subcarrier elements, and f 12 (i) is the channel estimate corresponding to the i-th subcarrier element in the second subcarrier element, and T color (·) is an amplitude and / or phase change value corresponding to a subcarrier element among the N subcarrier elements whose sequence number is the same as the sequence number of the i-th subcarrier element among the second subcarrier elements, the sequence number of the i-th subcarrier element among the first subcarrier elements is the same as the sequence number of the i-th subcarrier element among the N subcarrier elements, and the i-th subcarrier element among the second subcarrier elements is a subcarrier element whose sequence number is adjacent to the sequence number of the i-th subcarrier element among the N subcarrier elements, where i is a positive integer and 1≦i≦N.

[0166] For example, if the sequence numbers of N subcarrier elements are 8, 21, 23, 28, 32, and 50, then T Color [m]=2e jπ = -2, the first subcarrier elements are subcarrier elements with sequence numbers {8, 21, 23, 28, 32, 50}, the second subcarrier elements are subcarrier elements with sequence numbers {7, 20, 22, 27, 31, 49}, and 1 ≤ i ≤ 6. 11 (i) is the channel estimate corresponding to the i-th subcarrier element in {8, 21, 23, 28, 32, 50}. For example, f 11 (1) is the channel estimate corresponding to subcarrier element 8, and f 11 (2) is the channel estimate corresponding to subcarrier element 21, and so on. color (i) is the amplitude and / or phase change value corresponding to the i-th subcarrier element in {8, 21, 23, 28, 32, 50}. For example, T color (1) is the amplitude and / or phase change value corresponding to subcarrier element 8, i.e., T color (1)=T color[8]=-2, and T color (2) is the amplitude and / or phase change value corresponding to the subcarrier element 21, i.e., T color (2)=T color

[21] =-2, and so on.

[0167]

number

[0168] represents the opposite number of the corresponding channel estimate obtained after the ith subcarrier element in the first subcarrier element is demarked.

[0169] In this case, the sequence numbers of the subcarrier elements in the second subcarrier element are different from the sequence numbers of the subcarrier elements in the N subcarrier elements, so

[0170]

number

[0171] where f 12 (i) is the value of the i-th subcarrier element in {7, 20, 22, 27, 31, 49}. For example, f 12 (1) is the channel estimate corresponding to subcarrier element 7, and f 12 (2) is the channel estimate corresponding to subcarrier element 20, and so on.

[0172]

number

[0173] Note that in the case of , the N subcarrier elements include subcarrier elements with consecutive sequence numbers, and therefore there is a subcarrier element with a sequence number that is the same as the sequence number of the N subcarrier elements in the second subcarrier element.

[0174]

number

[0175] It can be understood that when is close to 0, the subcarrier element can be determined to be a marked subcarrier element.

[0176]

number

[0177] The second channel estimate value f2 obtained by summing f2 should also be close to 0. The second channel estimate value f2 can be a positive value, a negative value, or a complex value.

[0178] In this case, the first device may obtain the absolute value of the second channel estimate f2, i.e., |f2|, and set a first threshold based on the channel condition. When |f2| is smaller than the first threshold, the first device may determine that the L-LTF sequence corresponding to the currently received signal frame is the target L-LTF sequence. Conversely, the L-LTF sequence is not the target L-LTF sequence.

[0179] In yet another possible design solution, the first device may also determine whether the L-LTF sequence corresponding to the signal frame is a target L-LTF sequence based on the channel estimate of the subcarrier element whose sequence number corresponds to the sequence number of the N subcarrier elements and the amplitude and / or phase change value corresponding to the N subcarrier elements in the first channel estimate. For example, the first device may compensate the first channel estimate, and then compare the channel estimate of the subcarrier element whose sequence number corresponds to the sequence number of the N subcarrier elements in the compensated first channel estimate with the values ​​of the N subcarrier elements in a known L-LTF sequence (e.g., specified in a standard or determined by the transmitting end and the receiving end through negotiation and communication) based on the amplitude and / or phase change value corresponding to the N subcarrier elements. If the difference or ratio between the two values ​​is within a threshold range, it may be determined whether the L-LTF sequence corresponding to the current signal frame is a target L-LTF sequence. That is, the first device may compare the compensated channel estimate of the subcarrier element whose sequence number corresponds to the sequence number of the N subcarrier elements with the values ​​of the N subcarrier elements in the L-LTF sequence corresponding to the signal frame sent by the second device based on the amplitude and / or phase change values ​​corresponding to the N subcarrier elements to identify whether the current signal is a target frame.

[0180] When the channel condition is poor or the signal-to-noise ratio is low, based on determining the second channel estimate, the first device may further determine a third channel estimate based on the channel estimate corresponding to the first subcarrier element, the channel estimate corresponding to the second subcarrier element, and the amplitude and / or phase variation values ​​corresponding to the N subcarrier elements, wherein the third channel estimate is determined according to a third relationship:

[0181]

number

[0182] It should be noted that the third channel estimate f3 satisfies the following: The third channel estimate f3 can be understood to be obtained by unmarking the subcarrier elements that are considered to be marked in the L-LTF sequence corresponding to the current signal frame, obtaining the original channel estimates of the marked subcarrier elements, and adding and summing the original channel estimates and the channel estimates of the adjacent subcarrier elements. Based on this scheme, the reliability and accuracy of signal identification can be further improved.

[0183] When the L-LTF sequence corresponding to the current signal frame is the target L-LTF sequence,

[0184]

number

[0185] It can be understood that L-LTF sequence corresponding to the signal frame may be determined based on the second channel estimate and the third channel estimate.

[0186] For example, the ratio of the absolute value of the second channel estimate |f2| to the absolute value of the third channel estimate |f3|

[0187]

number

[0188] When the ratio of the absolute value of the second channel estimate to the absolute value of the third channel estimate is greater than or equal to the second threshold, the first device may determine that the L-LTF sequence corresponding to the signal frame is not the target L-LTF sequence.

[0189] The second threshold is a threshold greater than 0 and less than 1. The value of the second threshold may be set based on the channel state, device computing capability, application scenario, etc., which is not particularly limited in this embodiment of the present application.

[0190] Based on the above steps S801 to S804, when it is determined that the L-LTF sequence corresponding to the signal frame is the target L-LTF sequence, the first device may determine the signal frame as a target frame and continue receiving the signal frame. Conversely, when it is determined that the L-LTF sequence corresponding to the signal frame is not the target L-LTF sequence, the first device may determine that the signal frame is a non-target frame, immediately stop and terminate reception of the current signal frame, reset all receiving modules, and re-receive the air interface signal. In this case, if the target frame overlaps with the non-target frame, the signal frame on the air interface may be re-received in time, thus the target frame may be quickly captured and the loss of the target frame may be avoided, thereby quickly synchronizing the target frame for reception.

[0191] It should be noted that when the receiving end has multiple antennas, each receiving antenna may identify a signal according to the relevant description in S803 and S804, and an "or" operation may be performed on the identification results of each receiving antenna to determine whether a target signal is received. In other words, if one antenna determines a target signal, the receiving end may indicate the signal as a target signal.

[0192] Based on the signal identification method shown in Figure 8, the second device can identify a marking scheme for the amplitude and / or phase changes of the subcarrier elements in the L-LTF sequence, and the first device can identify the marking scheme for the subcarrier elements in the L-LTF sequence corresponding to the currently received signal frame based on the marking information of the subcarrier elements in the target L-LTF sequence, and can identify whether the current L-LTF sequence is a target L-LTF sequence marked by the target device with a specific marking scheme, so as to more quickly or earlier identify whether the current signal frame is a target frame. In the event of signal overlap, reception of non-target frames is terminated in time and reception of the target frame is resumed in advance, thereby reducing the signal packet loss rate and improving signal reception reliability.

[0193] The following describes in detail the signal identification method provided in the embodiments of the present application with reference to application scenarios. For example, the signal identification method provided in the embodiments of the present application can be applied to the diagram of intra-frequency cell deployment scenario shown in FIG. 14 and can be used to identify signals in intra-frequency cells. As shown in FIG. 14, in this scenario, four channels, namely, channels 1 to 4, are deployed based on Wi-Fi. Cells of the same frequency use the same channel for transmission. There are four intra-frequency cells using the same channel. Each intra-frequency cell corresponds to one AP. For example, an intra-frequency cell using channel 1 includes cells 1 to 4 and corresponds to APs 1 to 4. Cells of different frequencies do not affect each other. For example, signals sent by cells using channels 2 to 4 do not affect signals sent by cells using channel 1.

[0194] The first device is STA1 in cell 1, and the second device is AP1 in cell 1. In the process of sending a signal to STA1, AP1 receives a signal sent by an AP or STA in any one of cells 2 to 4, and a MIM is formed continuously. In this case, STA1 can identify the L-LTF sequence corresponding to the received signal frame and determine whether the signal frame is from AP1 in order to distinguish signals from different intra-frequency cells.

[0195] For example, a 20 MHz bandwidth is used as an example. APs (AP1 to AP4) to which cells 1 to 4 belong send signals by using L[1,64] as the L-LTF sequence in S801. For the same L-LTF sequence, AP1 to AP4 mark by using the subcarrier elements shown in Table 1. Each AP selects six subcarrier elements in L[1,64] for marking, and the sequence numbers of the selected six subcarrier elements are discontinuous. The sequence numbers of the selected and marked subcarrier elements among the four APs do not overlap. For example, AP1 selects the subcarrier elements with sequence numbers {8, 21, 23, 28, 32, 50} in L[1,64] for marking, and AP2 selects the subcarrier elements with sequence numbers {13, 15, 25, 42, 44, 58} in L[1,64] for marking.

[0196] Furthermore, AP1 to AP4 all use the same marking scheme to mark selected subcarrier elements, for example, the marking scheme is amplified by a factor of 2 and phase rotated by 180°, i.e., T color [m]=2*e jπ In AP1, the value of m is 8, 21, 23, 28, 32, or 50. In this case, N=6, and the mark information of N subcarrier elements is the sequence numbers of the six subcarrier elements {8, 21, 23, 28, 32, 50} and the amplitude and / or phase change values ​​T of the six subcarrier elements. Color [m]=-2.

[0197] [Table 1]

[0198] Since the L-LTF sequence L[1,64] contains 64 subcarrier elements, it can be understood that when each AP selects the same amount of subcarrier elements for marking, the amount of intra-frequency cells in the frequency to which the AP belongs and whether the sequence numbers of the subcarrier elements selected by different APs overlap need to be taken into consideration, so that the amount of selected subcarrier elements meets the requirement.

[0199] When AP1 sends a signal frame to STA1, AP1 needs to perform a marking process on the subcarrier elements with sequence numbers {8, 21, 23, 28, 32, 50} in the L-LTF sequence by doubling the amplitude and rotating the phase by 180°, and then send the signal frame formed by the marked L-LTF sequence, i.e., the target frame, to STA1. The subcarrier elements with sequence numbers {8, 21, 23, 28, 32, 50} may be referred to as target subcarrier elements.

[0200] Furthermore, STA1 may parse the currently received signal frame to obtain an L-LTF sequence corresponding to the current signal frame, perform channel estimation by using the L-LTF sequence obtained through the parsing to obtain a first channel estimate, and determine whether the marked subcarrier elements are subcarrier elements whose sequence numbers are {8, 21, 23, 28, 32, 50} based on the mark information of AP1's six subcarrier elements and the first channel estimate.

[0201] When the channel condition is good, if possible, STA1 may determine, based on the first channel estimate, whether there is an abruptly changed channel estimate in the first channel estimate, and determine whether the sequence number of the subcarrier element corresponding to the abruptly changed channel estimate is the sequence number of the target subcarrier element. If the sequence number of the subcarrier element corresponding to the abruptly changed channel estimate is the sequence number of the target subcarrier element, for example, the abruptly changed channel estimate in the first channel estimate is shown in Figures 12 and 13, STA1 may determine that the L-LTF sequence corresponding to the current signal frame is the target L-LTF sequence. If the sequence number of the subcarrier element corresponding to the abruptly changed channel estimate is not the sequence number of the target subcarrier element, for example, STA1 determines that the sequence numbers of the subcarrier elements corresponding to the abruptly changed channel estimate in the first channel estimate are {13, 15, 25, 42, 44, 58} and do not match the subcarrier elements with sequence numbers {8, 21, 23, 28, 32, 50}, and STA1 may determine that the L-LTF sequence corresponding to the current signal frame is not the target L-LTF sequence.

[0202] Furthermore, when STA1 determines that the sequence number of the subcarrier element corresponding to the abruptly changed channel estimate value is the target subcarrier element, STA1 may further divide the abruptly changed channel estimate value by the amplitude and / or phase change value of the target subcarrier element to obtain an unmarked channel estimate value, and compare the channel estimate value with the channel estimate value of the subcarrier element adjacent to the channel estimate value, for example, the channel estimate value of the subcarrier element with sequence numbers {7, 20, 22, 27, 31, 49}, to determine whether the obtained unmarked channel estimate value is consistent with the channel estimate value of the adjacent subcarrier element. For specific identification processing, please refer to the related description in step S803. Details will not be described again here.

[0203] In another possible case, STA1 may, based on the sequence number of the target subcarrier element, determine the channel estimate of the subcarrier element whose sequence number is the same as the sequence number of the target subcarrier element (i.e., the channel estimate corresponding to the first subcarrier element), for example, {f 11 (1)=H2[8], f 11 (2) = H2

[21] , f 11 (3) = H2

[23] , f 11 (4) = H2

[28] , f 11 (5) = H2

[32] , and f 11 (6)=H2

[50] } and the channel estimate of the subcarrier element whose sequence number is adjacent to the sequence number of the target subcarrier element (i.e., the channel estimate corresponding to the second subcarrier element), e.g., {f 12 (1)=H2[7], f 12 (2)=H2

[20] , f 12 (3) = H2

[22] , f 12 (4) = H2

[27] , f 12 (5) = H2

[31] , and f 12 (6)=H2

[49] } to search for a first channel estimate. Then, a value obtained by dividing the channel estimate of a subcarrier element whose sequence number is that of the target subcarrier element by the amplitude and / or phase change value of the target subcarrier element is separately compared with the channel estimates of subcarrier elements whose sequence numbers are adjacent to the sequence number of the target subcarrier element as follows:

[0204]

number

[0205] where: T color (1)=T color (2)=T color (3)=T color (4)=T color (5)=T color(6)=T color If [m]=−2, the L-LTF sequence corresponding to the current signal frame may be determined to be the target L-LTF sequence.

[0206] Conversely, STA1 may determine that the L-LTF sequence corresponding to the current signal frame is not the target L-LTF sequence.

[0207] In yet another possible case, STA1 may derive a second channel estimate, e.g.,

[0208]

number

[0209] can be determined.

[0210] It can be understood that when the L-LTF sequence corresponding to the current signal frame is the target L-LTF sequence, that is, when the subcarrier elements whose sequence numbers are {8, 21, 23, 28, 32, 50} in the L-LTF sequence corresponding to the current signal frame are the target subcarrier elements, the second channel estimate value f2 ≈ 0. Otherwise, if the signal frame currently received by STA1 is the signal frame sent by AP2, the second channel estimate value f2 is changed to the sum of the amplitudes in the same direction, and the second channel estimate value f2 is greater than 0.

[0211] Furthermore, STA1 obtains the absolute value of the second channel estimation value f2, and when |f2| is smaller than the first threshold, STA1 may determine that the L-LTF sequence corresponding to the current signal frame is the target L-LTF sequence. Conversely, STA1 may determine that the L-LTF sequence corresponding to the current signal frame is not the target L-LTF sequence. For specific identification processing, please refer to the relevant descriptions in steps S803 and S804. Details will not be described again here.

[0212] In yet another possible case, for example, when the channel condition is poor or the signal-to-noise ratio is low, when determining the second channel estimate, STA1 may determine a third channel estimate, for example, based on the channel estimate corresponding to the first subcarrier element, the channel estimate corresponding to the second subcarrier element, and the amplitude and / or phase change value of the target subcarrier element.

[0213]

number

[0214] may further be determined.

[0215] It can be understood that if the subcarrier elements with sequence numbers {8, 21, 23, 28, 32, 50} in the L-LTF sequence corresponding to the current signal frame are the target subcarrier elements, the third channel estimate f3 needs to be the sum of positive amplitudes, for example, twice the sum of channel estimates corresponding to the subcarrier elements with sequence numbers {7, 20, 22, 27, 31, 49}. Conversely, if the signal frame currently received by STA1 is the signal frame sent by AP2, the third channel estimate f3 is changed to an inverse amplitude cancellation, for example, half the sum of channel estimates corresponding to the subcarrier elements with sequence numbers {7, 20, 22, 27, 31, 49}.

[0216] Furthermore, STA1 may make a decision by combining the second channel estimate and the third channel estimate. For example, STA1 may determine whether the absolute value of the second channel estimate |f2| is greater than the absolute value of the third channel estimate |f3|.

[0217]

number

[0218] Decisions can be made based on:

[0219]

number

[0220] When is smaller than the second threshold and the value of the second threshold is [0, 1], STA1 may determine that the L-LTF sequence corresponding to the current signal frame is the target L-LTF sequence.

[0221]

number

[0222] When is greater than the second threshold, STA1 may determine that the L-LTF sequence corresponding to the current signal frame is not the target L-LTF sequence. For specific identification processing, please refer to the relevant descriptions in steps S803 and S804. The details will not be described again here.

[0223] Based on any one of the above determination processes, STA1 may determine whether the current signal frame is a target frame based on determining whether the L-LTF sequence corresponding to the current signal frame is a target L-LTF sequence, and therefore may determine whether to continue receiving the current signal frame. For example, when STA1 determines that the L-LTF sequence corresponding to the current signal frame is not the target L-LTF sequence, STA1 immediately stops receiving the current signal frame, reacquires the air interface, and synchronizes with AP1's signal frame.

[0224] It can be understood that STA1 can also identify the signal frame sent by any one of AP2 to 4 or STA2 to 4 based on the above identification process, and AP2 to 4 or STA2 to 4 can also identify the target signal based on the above identification process. Details will not be described in this embodiment of the present application.

[0225] Note that the sequence numbers of the subcarrier elements selected for different APs for marking shown in Table 1 do not overlap with each other. To distinguish signals of more cells, subcarrier elements with some overlapping sequence numbers may be selected for marking for different APs. As shown in Table 2 below, the subcarrier elements used by AP1 and AP2 for marking each include subcarrier element 28, the subcarrier elements used by AP2 and AP3 for marking each include subcarrier elements 17, 37, and 52, and the subcarrier elements used by AP3 and AP4 for marking each include subcarrier elements 10 and 39.

[0226] [Table 2]

[0227] In order to distinguish the signals of more cells, different APs may select different amounts of subcarrier elements for marking. As shown in Table 3 below, the amount of subcarrier elements used by AP1 for marking is 3, the amount of subcarrier elements used by AP2 for marking is 4, the amount of subcarrier elements used by AP3 for marking is 6, and the amount of subcarrier elements used by AP4 for marking is 5.

[0228] [Table 3]

[0229] Furthermore, when different APs use the same marking scheme and use a large number of subcarrier elements with overlapping sequence numbers, misidentification may occur. In this case, different APs may mark subcarrier elements with different marking schemes, thus achieving higher signal discrimination, avoiding misidentification, and distinguishing more users. For example, the marking scheme of AP1 for the subcarrier elements shown in Table 1, Table 2, or Table 3 is T color [m]=-2, and the manner in which AP2 marks the subcarrier elements shown in Table 1, Table 2, or Table 3 is:

[0230]

number

[0231] and the manner in which AP3 marks the subcarrier elements shown in Table 1, Table 2, or Table 3 is:

[0232]

number

[0233] and the scheme by which AP4 marks the subcarrier elements whose sequence numbers are shown in Table 1, Table 2, or Table 3 is:

[0234]

number

[0235] Furthermore, for any AP, different marking schemes may be used for all selected subcarrier elements, or the same marking scheme may be used for some subcarrier elements, which is not particularly limited in this embodiment of the present application.

[0236] In the scenario shown in Figure 14, APs to which different cells belong may use different specific marking schemes for L-LTF sequences, and therefore, STAs may distinguish signals from different cells based on the marking schemes corresponding to the target signals.

[0237] The signal identification method provided in this embodiment of the present application can also be applied to the scenario shown in Figure 15 and can be used to distinguish signals sent by different users in the same cell. As shown in Figure 15, there are four different user equipments STA1 to STA4 in the cell to which AP1 belongs. When user equipments in the same cell send signals, there is also the problem of signal collision, so different users may also use different marking schemes for L-LTF sequences to distinguish their signals. For specific marking schemes, please refer to the marking schemes of AP1 to AP4 in the scenario of Figure 13. The details will not be described again here.

[0238] For example, STA1 and STA2 are hidden nodes described in the scenario in FIG. 2. Therefore, when STA2 sends a signal to AP1, STA1 determines that the channel is idle and therefore sends a signal to AP1, causing signal overlap. If the importance coefficient of the data sent by STA1 at the moment is higher, AP1 may identify the currently received signal based on the mark information used by STA1. For specific signal identification processing, please refer to the related descriptions in S802 and S803, or the related description of STA1 identifying the signal sent by AP1 in the scenario shown in FIG. 13. Details will not be described again here.

[0239] In another example, the signal identification method provided in this embodiment of the present application may be further applied to the scenario shown in FIG. 16. As shown in FIG. 16, Cell 1, to which AP1 belongs, and Cell 2, to which AP2 belongs, are intra-frequency cells, and the two cells are separated by a certain distance. When the RSSI between AP1 and AP2 is greater than the ED / CS threshold, AP1 and AP2 can hear each other. However, because there is a certain distance between AP1 and AP2, the strength of the signal sent by AP1 and detected by STA1 is much stronger than the strength of the signal sent by AP2 and detected by STA1. Therefore, in this case, when signal overlap occurs, STA1 can analyze the signal sent by AP1, and when AP1 sends a signal to STA1, AP2 can also send a signal to STA2, and the signal paths do not affect each other.

[0240] However, in this case, if AP2 first sends a signal to STA2, AP1 can find through sensing that AP2 is sending a signal, so AP1 determines that the channel is busy when sensing the channel, and therefore AP1 backs off and sends a signal after AP2 finishes sending a signal. As shown in Figure 17, signals in Cell 1 and signals in Cell 2 are sent alternately. In this case, only one AP sends a signal at a time, which greatly reduces air interface utilization.

[0241] Therefore, AP1 and AP2 may also mark the L-LTF sequence with different marking schemes. For specific marking schemes, please refer to the marking schemes of AP1 to AP4 in the scenario in FIG. 13. The details will not be described again here. Therefore, when receiving a signal sent by AP2, AP1 may identify the L-LTF sequence corresponding to the signal sent by AP2 and determine whether the current signal is a signal in the cell (cell 1) in which AP1 is located. If the current signal is not a signal in the cell in which AP1 is located, AP1 may determine that the channel is idle and may send a signal without backoff waiting. As shown in FIG. 18, the signal in cell 1 and the signal in cell 2 may be sent in parallel, i.e., AP2 may send a signal to STA2, and AP1 may also send a signal to STA1. Similarly, STA1 and AP2 may also determine whether a signal can be sent by detecting whether the current signal is a signal sent in the cell in which STA1 and AP2 are located. For specific signal identification processing, please refer to the relevant descriptions in S803 and S804, or the relevant descriptions of identifying the signal sent by AP1 by STA1 in the scenario shown in Figure 13. The details will not be described again here.

[0242] Note that in the scenario shown in FIG. 16, after parsing the L-LTF, the receiving end may determine whether the channel is idle, and then the receiving end may start sending data.

[0243] In the scenario shown in Figure 16, the signal identification method provided in this embodiment of the present application is used, so that smarter channel busy / idle detection can be formed, and the problem that different intra-frequency cells cannot carry out parallel data transmission due to false determination that the channel is busy caused by clear channel assessment (CCA) can be avoided, and spectrum utilization can be improved.

[0244] In the above embodiments, it may be understood that the methods and / or steps implemented by the first device may also be implemented by components (e.g., a processor, a chip, a chip system, a circuit, a logic module, or software) that may be used in the first device, and that the methods and / or steps implemented by the second device may also be implemented by components (e.g., a processor, a chip, a chip system, a circuit, a logic module, or software) that may be used in the second device.

[0245] The above mainly describes the solution provided in the present application. Correspondingly, the present application further provides a communication device. The communication device is configured to implement the method in the above method embodiment. The communication device may be the first device in the method embodiment, an apparatus including the first device, or a component that can be used in the first device, such as a chip or a chip system. Alternatively, the communication device may be the second device in the method embodiment, an apparatus including the second device, or a component that can be used in the second device, such as a chip or a chip system.

[0246] It can be understood that to implement the above functions, the communication device includes corresponding hardware structures and / or software modules for implementing each function. Those skilled in the art can easily recognize that the present application can be implemented by hardware or a combination of hardware and computer software, in combination with the example units and algorithm steps described in the embodiments disclosed herein. Whether the functions are implemented by hardware or by hardware driven by computer software depends on the specific application and design constraints of the technical solution. Those skilled in the art may use different methods to implement the described functions for each specific application, but the implementation form should not be considered to exceed the scope of the present application.

[0247] In the embodiments of the present application, the division into functional modules may be implemented on the communication device based on the above method embodiments. For example, each functional module may be obtained through division based on each corresponding function, or two or more functions may be integrated into one processing module. The integrated module may be implemented in the form of hardware or in the form of a software function module. It should be noted that in the embodiments of the present application, the division into modules is merely an example and is merely a logical function division. In actual implementation, other division methods may be used.

[0248] For example, the communication device is a terminal device or a network device in the above method embodiments. Figure 19 is a diagram of the structure of a communication device according to one embodiment of the present application. As shown in Figure 19, the communication device 1900 includes a processing module 1901 and a transceiver module 1902.

[0249] For example, the communication apparatus 1900 is the first device in the above method embodiment.

[0250] The transceiver module 1902 is configured to receive signal frames; The processing module 1901 is configured to perform channel estimation based on a legacy long training field (L-LTF) sequence corresponding to the signal frame to obtain a first channel estimate, where the first channel estimate includes a channel estimate corresponding to M subcarrier elements in the L-LTF sequence corresponding to the signal frame; The processing module 1901 is further configured to determine whether the L-LTF sequence corresponding to the signal frame is a target L-LTF sequence based on the first channel estimate and mark information of the N subcarrier elements, where the mark information of the N subcarrier elements includes sequence numbers of the N subcarrier elements and amplitude and / or phase change values ​​corresponding to the N subcarrier elements, and M and N are positive integers, where M>1, 1≦N≦M.

[0251] In a possible design solution, the processing module 1901 is further configured to determine whether an L-LTF sequence corresponding to the signal frame is a target L-LTF sequence based on a channel estimate corresponding to a first subcarrier element and amplitude and / or phase change values ​​corresponding to the N subcarrier elements, where the first subcarrier element is a subcarrier element in the L-LTF sequence corresponding to the signal frame, whose subcarrier element sequence number corresponds to the sequence number of the N subcarrier elements.

[0252] In another possible design solution, the processing module 1901 may: determine a first subcarrier element and a second subcarrier element based on sequence numbers of the N subcarrier elements, where the first subcarrier element is a subcarrier element in an L-LTF sequence corresponding to the signal frame, whose subcarrier element sequence number corresponds to the sequence number of the N subcarrier elements, and the second subcarrier element is a subcarrier element in an L-LTF sequence corresponding to the signal frame, whose subcarrier element sequence number is adjacent to the sequence number of the N subcarrier elements; Determine whether the L-LTF sequence corresponding to the signal frame is a target L-LTF sequence based on a channel estimate corresponding to the first subcarrier element, a channel estimate corresponding to the second subcarrier element, and amplitude and / or phase change values ​​corresponding to the N subcarrier elements in the first channel estimate. It is further configured as follows.

[0253] In a possible design solution, the processing module 1901 may include: determining a second channel estimate based on a channel estimate corresponding to the first subcarrier element, a channel estimate corresponding to the second subcarrier element, and amplitude and / or phase change values ​​corresponding to the N subcarrier elements, wherein the second channel estimate satisfies a first relationship

[0254]

number

[0255] where the sequence number of the i-th subcarrier element in the second subcarrier element is different from the sequence number of the subcarrier element in the N subcarrier elements, F_f 12 (i)=f 12 (i) or the sequence number of the i-th subcarrier element in the second subcarrier element is the same as the sequence number of the subcarrier element in the N subcarrier elements;

[0256]

number

[0257] where f2 is the second channel estimate and f 11 (i) is the channel estimate corresponding to the i-th subcarrier element in the first subcarrier element, and T color (i) is the amplitude and / or phase change value corresponding to the i-th subcarrier element among the N subcarrier elements, and f12 (i) is the channel estimate corresponding to the i-th subcarrier element in the second subcarrier element, and T color (·) is an amplitude and / or phase change value corresponding to a subcarrier element among the N subcarrier elements whose sequence number is the same as the sequence number of the i-th subcarrier element among the second subcarrier elements, the sequence number of the i-th subcarrier element among the first subcarrier elements is the same as the sequence number of the i-th subcarrier element among the N subcarrier elements, and the i-th subcarrier element among the second subcarrier elements is a subcarrier element whose sequence number is adjacent to the sequence number of the i-th subcarrier element among the N subcarrier elements, where i is a positive integer and 1≦i≦N; When the absolute value of the second channel estimate is smaller than the first threshold, determining that the L-LTF sequence corresponding to the signal frame is the target L-LTF sequence; or When the absolute value of the second channel estimate is greater than or equal to the first threshold, it is determined that the L-LTF sequence corresponding to the signal frame is not the target L-LTF sequence. It is further configured as follows.

[0258] In another possible design solution, the processing module 1901 may: determining a second channel estimate and a third channel estimate based on a channel estimate corresponding to the first subcarrier element, a channel estimate corresponding to the second subcarrier element, and amplitude and / or phase change values ​​corresponding to the N subcarrier elements, wherein the second channel estimate is determined based on a second relationship:

[0259]

number

[0260] and the third channel estimate satisfies the third relationship

[0261]

number

[0262] where the sequence number of the i-th subcarrier element in the second subcarrier element is different from the sequence number of the subcarrier element in the N subcarrier elements, F_f 12 (i)=f 12 (i) or the sequence number of the i-th subcarrier element in the second subcarrier element is the same as the sequence number of the subcarrier element in the N subcarrier elements;

[0263]

number

[0264] where f2 is the second channel estimate, f3 is the third channel estimate, and f 11 (i) is the channel estimate corresponding to the i-th subcarrier element in the first subcarrier element, and T color (i) is the amplitude and / or phase change value corresponding to the i-th subcarrier element among the N subcarrier elements, and f 12 (i) is the channel estimate corresponding to the i-th subcarrier element in the second subcarrier element, and T color (·) is an amplitude and / or phase change value corresponding to a subcarrier element among the N subcarrier elements whose sequence number is the same as the sequence number of the i-th subcarrier element among the second subcarrier elements, the sequence number of the i-th subcarrier element among the first subcarrier elements is the same as the sequence number of the i-th subcarrier element among the N subcarrier elements, and the i-th subcarrier element among the second subcarrier elements is a subcarrier element whose sequence number is adjacent to the sequence number of the i-th subcarrier element among the N subcarrier elements, where i is a positive integer and 1≦i≦N; Determine whether the L-LTF sequence corresponding to the signal frame is a target L-LTF sequence based on the second channel estimate and the third channel estimate. It is further configured as follows.

[0265] In a possible design solution, the processing module 1901 may include: When the ratio of the absolute value of the second channel estimate to the absolute value of the third channel estimate is smaller than a second threshold, determine that the L-LTF sequence corresponding to the signal frame is a target L-LTF sequence; or When a ratio between the absolute value of the second channel estimate and the absolute value of the third channel estimate is equal to or greater than a second threshold, it is determined that the L-LTF sequence corresponding to the signal frame is not a target L-LTF sequence. It is further configured as follows.

[0266] For example, the communication apparatus 1900 is the second device in the above method embodiment.

[0267] The processing module 1901 is configured to mark the amplitude and / or phase of N subcarrier elements in a legacy long training field L-LTF sequence corresponding to a signal frame, where the L-LTF sequence corresponding to the signal frame includes M subcarrier elements, M and N are positive integers, M>1, 1≦N≦M; The transceiver module 1902 is configured to send a signal frame to a first device.

[0268] In a possible design solution, when the N subcarrier elements include subcarriers with consecutive sequence numbers, the amplitude and phase change values ​​of the subcarrier elements with adjacent sequence numbers are different.

[0269] Optionally, in this embodiment of the present application, the transceiver module 1902 may include a receiving module and a transmitting module (not shown in FIG. 19). The transceiver module is configured to implement transmitting and receiving functions of the communication device 1900.

[0270] Optionally, the communication device 1900 may further include a storage module (not shown in FIG. 19). The storage module stores programs or instructions. When the processing module 1901 executes the programs or instructions, the communication device 1900 may perform the functions of the first device or the second device in the method shown in FIG.

[0271] It should be understood that the processing module 1901 in the communication device 1900 may be implemented by a processor or processor-related circuitry, and may be a processor or a processing unit. The transceiver module 1902 may be implemented by a transceiver or transceiver-related circuitry, and may be a transceiver or a transceiver unit.

[0272] All relevant contents of the steps in the above method embodiments can be cited in the functional descriptions of the corresponding functional modules, and will not be described in detail again here.

[0273] The communication device 1900 provided in this embodiment may implement the above-mentioned signal identification method, so please refer to the above-mentioned method embodiments for the technical effects that can be achieved by the communication device 1900. Details will not be described again here.

[0274] For example, Figure 20 is a diagram of the structure of another communication device according to an embodiment of the present application. The communication device may be a first device or a second device, or may be a chip (system) or another part or component that may be disposed in the first device or the second device. As shown in Figure 20, the communication device 2000 may include a processor 2001. Optionally, the communication device 2000 may further include a memory 2002 and / or a transceiver 2003. The processor 2001 may be coupled to the memory 2002 and the transceiver 2003 and may be connected to the memory 2002 and the transceiver 2003 through a communication bus, for example.

[0275] Each component of the communication device 2000 will be described in detail below with reference to FIG.

[0276] Processor 2001 is the control center of communication device 2000 and may be a single processor or a collective term for multiple processing elements. For example, processor 2001 may be one or more central processing units (CPUs), or application-specific integrated circuits (ASICs), or one or more integrated circuits configured to implement embodiments of the present application, such as one or more microprocessors (digital signal processors, DSPs) or one or more field programmable gate arrays (FPGAs).

[0277] Optionally, the processor 2001 may implement various functions of the communication device 2000 by running or executing software programs stored in the memory 2002 and accessing data stored in the memory 2002.

[0278] During a particular implementation, in one embodiment, the processor 2001 may include one or more CPUs, for example, CPU0 and CPU1 shown in FIG.

[0279] During a particular implementation, in one embodiment, the communications device 2000 may also include multiple processors, such as processor 2001 and processor 2004 shown in FIG. 20. Each of the processors may be a single-core processor (single CPU) or a multi-core processor (multiple CPUs). A processor herein may be one or more devices, circuits, and / or processing cores configured to process data (e.g., computer program instructions).

[0280] The memory 2002 is configured to store a software program for implementing the solution of the present application, and the processor 2001 controls the execution of the software program. For specific implementation, please refer to the above method embodiment. The details will not be described again here.

[0281] Optionally, memory 2002 may be read-only memory (ROM) or another type of static storage device capable of storing static information and instructions, random access memory (RAM) or another type of dynamic storage device capable of storing information and instructions, or may be electrically erasable programmable read-only memory (EEPROM), compact disc read-only memory (CD-ROM) or other compact disc storage, optical disc storage (including compact discs, laser discs, optical discs, digital versatile discs, Blu-ray discs, etc.), magnetic disc storage or other magnetic storage device, or any other medium that can be used to carry or store expected program code in the form of instructions or data structures and that can be accessed by a computer. However, this is not limited thereto. Memory 2002 may be integrated with processor 2001 or may exist independently and be coupled to processor 2001 through interface circuitry (not shown in FIG. 20 ) of communication device 2000. This is not particularly limited in this embodiment of the present application.

[0282] The transceiver 2003 is configured to communicate with another communication device. For example, the communication device 2000 is a terminal device, and the transceiver 2003 may be configured to communicate with a network device or another terminal device. In another example, the communication device 2000 is a network device, and the transceiver 2003 may be configured to communicate with a terminal device or another network device.

[0283] Optionally, the transceiver 2003 may include a receiver and a transmitter (not shown separately in FIG. 20), where the receiver is configured to implement a receiving function and the transmitter is configured to implement a sending function.

[0284] Optionally, the transceiver 2003 may be integrated with the processor 2001 or may exist independently and be coupled to the processor 2001 through an interface circuit (not shown in FIG. 20) of the communication device 2000. This is not particularly limited in this embodiment of the present application.

[0285] Optionally, the processor 2001 is mainly configured to process communication protocols and communication data, control the entire communication device, execute software programs, and process data of the software programs. The memory 2002 is mainly configured to store software programs and data. The transceiver 2003 may include a radio frequency circuit and an antenna. The radio frequency circuit is mainly configured to convert between baseband signals and radio frequency signals and process radio frequency signals. The antenna is mainly configured to receive and transmit radio frequency signals in the form of electromagnetic waves. The input / output device, for example, a touch screen, a display, or a keyboard, is mainly configured to receive data input by a user and output data to the user.

[0286] The processor 2001, the transceiver 2003, and the memory 2002 may be connected through a communication bus.

[0287] After the communication device is powered on, the processor 2001 can read the software program from the memory 2002, interpret and execute the instructions of the software program, and process the data of the software program. When data needs to be sent wirelessly, the processor 2001 performs baseband processing on the data to be sent and then outputs the baseband signal to the radio frequency circuit. The radio frequency circuit performs radio frequency processing on the baseband signal and then sends the radio frequency signal in the form of electromagnetic waves through an antenna. When data is sent to the communication device, the radio frequency circuit receives the radio frequency signal through the antenna, converts the radio frequency signal to a baseband signal, and outputs the baseband signal to the processor 2001. The processor 2001 converts the baseband signal to data and processes the data.

[0288] In another implementation, the radio frequency circuitry and antenna may be located independently from the processor that performs the baseband processing, e.g., in a distributed scenario, the radio frequency circuitry and antenna may be located independently and remotely from the communication device.

[0289] The processor 2001 may be configured, for example, but not limited to, to perform baseband-related processing, and the transceiver 2003 may be configured, for example, but not limited to, to perform radio frequency transmission or reception. The above components may be separately disposed on chips independent of each other, or at least some or all of the components may be disposed on the same chip. For example, the processor may be divided into an analog baseband processor and a digital baseband processor. The analog baseband processor and the transceiver may be integrated on the same chip, and the digital baseband processor may be disposed on a separate chip. With the continuous development of integrated circuit technology, an increasing number of components may be integrated on the same chip. For example, a digital baseband processor may be integrated on the same chip as multiple application processors (for example, but not limited to, a geometric processor and a multimedia processor). A chip may be referred to as a system on chip. Whether components are independently disposed on different chips or disposed on one or more chips in an integrated manner typically depends on the specific requirements of a product design. The specific implementation of the components is not limited to embodiments of the present invention.

[0290] It should be noted that the structure of the communications device 2000 shown in Figure 20 is not intended to be a limitation on the communications device. An actual communications device may include more or fewer components than those shown in the figure, may combine some components, or may have a different component arrangement.

[0291] Furthermore, for the technical effects of the communication device 2000, please refer to the technical effects of the communication method in the above method embodiments, and the details will not be described again here.

[0292] An embodiment of the present application provides a communication system, which includes the first device and the second device.

[0293] In some embodiments, the present application further provides a communications device, the communications device being configured to implement the method in any one of the above method embodiments.

[0294] In a possible implementation, the communication device further includes a memory. The memory is configured to store necessary computer programs and data. The computer programs may include instructions. The processor may call the instructions in the computer programs stored in the memory to instruct the communication device to perform the method in any one of the above method embodiments. Of course, the communication device may not include a memory.

[0295] In another possible implementation, the communication device further includes an interface circuit, which is a code / data read / write interface circuit configured to receive computer-executable instructions (wherein the computer-executable instructions may be stored in a memory and read directly from the memory or read through another component) and to transmit the computer-executable instructions to a processor.

[0296] In yet another possible implementation, the communication device further includes a communication interface, the communication interface configured to communicate with a module other than the communication device.

[0297] It can be understood that the communication device can be a chip or a chip system. When the communication device is a chip system, the communication device can include a chip, or can include a chip and another individual component. This is not particularly limited in this embodiment of the present application.

[0298] The present application further provides a computer-readable storage medium, which stores a computer program or instructions, which, when executed by a computer, implements the functions of any one of the above method embodiments.

[0299] The present application further provides a computer program product, which, when executed by a computer, implements the functions of any one of the above method embodiments.

[0300] Those skilled in the art may understand that for the purpose of convenient and concise description, the detailed operation processes of the above systems, devices and units may refer to the corresponding processes in the above method embodiments, and the details will not be described again here.

[0301] It should be understood that the term "and / or" herein describes only the association between associated objects and represents that three relationships may exist. For example, A and / or B may represent the following three cases: only A is present, both A and B are present, and only B is present, and A and B may be singular or plural. Furthermore, the character " / " herein usually indicates an "or" relationship between associated objects, but may also indicate an "and / or" relationship. For further details, please refer to the context for understanding.

[0302] As used herein, "at least one" means one or more, and "multiple" means two or more. "At least one of the following items" or similar phrases means any combination of these items, including any combination of singular or plural items. For example, at least one item of a, b, or c may refer to a, b, c, a and b, a and c, b and c, or a, b, and c, where a, b, and c may be singular or plural.

[0303] It should be understood that the sequence numbers of the above processes do not mean the execution sequence in various embodiments of the present application. The execution sequence of the processes should be determined based on the functions and internal logic of the processes, and should not be construed as any limitation on the implementation process of the embodiments of the present application.

[0304] It may be understood that the systems, devices, and methods described in this application may alternatively be implemented in other manners. For example, the device embodiments described are merely examples. For example, the division into units is merely a logical functional division, and other divisions may be used in actual implementation. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not implemented. Furthermore, the shown or described mutual couplings or direct couplings or communication connections may be implemented through some interfaces. Indirect couplings or communication connections between devices or units may be implemented in electrical, mechanical, or other forms.

[0305] The units described as separate parts may or may not be physically separate, i.e., they may be located in one place or distributed over multiple network units. The parts shown as units may or may not be physical units. Some or all of the units may be selected based on actual requirements to achieve the objectives of the solutions of the embodiments.

[0306] Furthermore, the functional units in the embodiments of the present application may be integrated into one processing unit, or each of the units may exist physically alone, or two or more units may be integrated into one unit.

[0307] All or part of the above embodiments may be implemented by software, hardware, firmware, or any combination thereof. When a software program is used to implement the embodiments, the embodiments may be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the procedures or functions according to the embodiments of the present application are generated entirely or partially. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted from a computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions may be transmitted from a website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optics, or digital subscriber line (DSL)) or wireless (e.g., infrared, radio, or microwave) transmission. The computer-readable storage medium may be any available medium accessible by a computer, or a data storage device such as a server or data center that integrates one or more available media. The available medium may be a magnetic medium (e.g., a floppy disk, a hard disk, or a magnetic tape), an optical medium (e.g., a DVD), a semiconductor medium (e.g., a solid state disk (SSD)), etc. In an embodiment of the present application, the computer may include the devices described above.

[0308] Although the present application is described with reference to embodiments, in the process of implementing the claimed application, those skilled in the art may understand and implement other variations of the disclosed embodiments by studying the accompanying drawings, the disclosed content, and the appended claims. In the claims, "comprising" does not exclude other elements or steps, and "a" or "one" does not exclude a plurality. A single processor or other unit may implement several functions recited in the claims. Although certain measures are recited in mutually different dependent claims, this does not indicate that these measures cannot be combined to produce better effects.

[0309] Although the present application is described with reference to specific features and embodiments thereof, it is clear that various modifications and combinations can be made thereto without departing from the spirit and scope of the present application. Accordingly, this specification and the accompanying drawings are merely exemplary descriptions of the present application as defined by the appended claims, and any or all modifications, variations, combinations, or equivalents encompassing the scope of the present application are to be considered. It is clear that a person skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. In this case, the present application is intended to cover these modifications and variations of the present application, provided that they fall within the scope of protection defined by the claims of the present application and their equivalent technologies.

Claims

1. 1. A method for signal identification, said method comprising: receiving, by a first device, a signal frame; performing, by the first device, channel estimation based on a legacy long training field (L-LTF) sequence corresponding to the signal frame to obtain a first channel estimate, the first channel estimate including a channel estimate corresponding to M subcarrier elements in the L-LTF sequence corresponding to the signal frame; determining, by the first device, whether the L-LTF sequence corresponding to the signal frame is a target L-LTF sequence based on the first channel estimate and mark information of N subcarrier elements, wherein the mark information of the N subcarrier elements includes sequence numbers of the N subcarrier elements and amplitude and / or phase change values ​​corresponding to the N subcarrier elements, where M and N are positive integers, M>1, 1≦N≦M; A signal identification method comprising:

2. The step of determining, by the first device, whether the L-LTF sequence corresponding to the signal frame is a target L-LTF sequence based on the first channel estimate and mark information of N subcarrier elements includes: determining, by the first device, a first subcarrier element and a second subcarrier element based on the sequence numbers of the N subcarrier elements, wherein the first subcarrier element is a subcarrier element whose subcarrier element sequence number corresponds to the sequence number of the N subcarrier elements in the L-LTF sequence corresponding to the signal frame, and the second subcarrier element is a subcarrier element whose subcarrier element sequence number is adjacent to the sequence number of the N subcarrier elements in the L-LTF sequence corresponding to the signal frame; determining, by the first device, whether the L-LTF sequence corresponding to the signal frame is the target L-LTF sequence based on a channel estimate corresponding to the first subcarrier element, a channel estimate corresponding to the second subcarrier element, and the amplitude and / or phase change values ​​corresponding to the N subcarrier elements in the first channel estimate; 10. The method of claim 1, comprising:

3. The step of determining, by the first device, whether the L-LTF sequence corresponding to the signal frame is the target L-LTF sequence based on a channel estimate corresponding to the first subcarrier element, a channel estimate corresponding to the second subcarrier element, and the amplitude and / or phase change values ​​corresponding to the N subcarrier elements in the first channel estimate, includes: determining, by the first device, a second channel estimate based on the channel estimate corresponding to the first subcarrier element, the channel estimate corresponding to the second subcarrier element, and the amplitude and / or phase change values ​​corresponding to the N subcarrier elements, wherein the second channel estimate satisfies a first relationship: [Equation 1] 【number】 Fulfilling When the sequence number of the i-th subcarrier element in the second subcarrier element is different from the sequence number of the subcarrier element in the N subcarrier elements, F_ ｆ１２ (i) = f １２ (i) or When the sequence number of the i-th subcarrier element in the second subcarrier element is the same as the sequence number of the subcarrier element in the N subcarrier elements, [Equation 2] where f ２ is the second channel estimate, and f １１ (i) is a channel estimate corresponding to the i-th subcarrier element in the first subcarrier element, and T ｃｏｌｏｒ (i) is an amplitude and / or phase change value corresponding to the i-th subcarrier element among the N subcarrier elements; １２ (i) is a channel estimate corresponding to the i-th subcarrier element in the second subcarrier element, and T ｃｏｌｏｒ (·) is an amplitude and / or phase change value corresponding to a subcarrier element in the N subcarrier elements, the sequence number of which is the same as the sequence number of the i-th subcarrier element in the second subcarrier elements, the sequence number of the i-th subcarrier element in the first subcarrier elements is the same as the sequence number of the i-th subcarrier element in the N subcarrier elements, and the i-th subcarrier element in the second subcarrier elements is a subcarrier element whose sequence number is adjacent to the sequence number of the i-th subcarrier element in the N subcarrier elements, where i is a positive integer and 1≦i≦N; determining, by the first device, that the L-LTF sequence corresponding to the signal frame is the target L-LTF sequence when the absolute value of the second channel estimate is less than a first threshold; or determining, by the first device, that the L-LTF sequence corresponding to the signal frame is not the target L-LTF sequence when the absolute value of the second channel estimate is greater than or equal to the first threshold; 3. The method of claim 2, comprising:

4. The step of determining, by the first device, whether the L-LTF sequence corresponding to the signal frame is the target L-LTF sequence based on a channel estimate corresponding to the first subcarrier element, a channel estimate corresponding to the second subcarrier element, and the amplitude and / or phase change values ​​corresponding to the N subcarrier elements in the first channel estimate, includes: determining, by the first device, a second channel estimate and a third channel estimate based on the channel estimate corresponding to the first subcarrier element, the channel estimate corresponding to the second subcarrier element, and the amplitude and / or phase change values ​​corresponding to the N subcarrier elements, wherein the second channel estimate is determined according to a second relationship: [Equation 3] and the third channel estimate satisfies a third relationship: [Equation 4] where F_f is a sequence number of the i-th subcarrier element in the second subcarrier element, and F_f is a sequence number of the i-th subcarrier element in the N subcarrier elements. １２ (i) = f １２ (i) or When the sequence number of the i-th subcarrier element in the second subcarrier element is the same as the sequence number of the subcarrier element in the N subcarrier elements, [Equation 5] where f ２ is the second channel estimate, and f ３ is the third channel estimate, and f １１ (i) is a channel estimate corresponding to the i-th subcarrier element in the first subcarrier element, and T ｃｏｌｏｒ (i) is an amplitude and / or phase change value corresponding to the i-th subcarrier element among the N subcarrier elements; １２ (i) is a channel estimate corresponding to the i-th subcarrier element in the second subcarrier element, and T ｃｏｌｏｒ (·) is an amplitude and / or phase change value corresponding to a subcarrier element in the N subcarrier elements, the sequence number of which is the same as the sequence number of the i-th subcarrier element in the second subcarrier elements, the sequence number of the i-th subcarrier element in the first subcarrier elements is the same as the sequence number of the i-th subcarrier element in the N subcarrier elements, and the i-th subcarrier element in the second subcarrier elements is a subcarrier element whose sequence number is adjacent to the sequence number of the i-th subcarrier element in the N subcarrier elements, where i is a positive integer and 1≦i≦N; determining, by the first device, whether the L-LTF sequence corresponding to the signal frame is the target L-LTF sequence based on the second channel estimate and the third channel estimate; 3. The method of claim 2, comprising:

5. The step of determining, by the first device, whether the L-LTF sequence corresponding to the signal frame is the target L-LTF sequence based on the second channel estimate and the third channel estimate includes: determining, by the first device, that the L-LTF sequence corresponding to the signal frame is the target L-LTF sequence when a ratio between the absolute value of the second channel estimate and the absolute value of the third channel estimate is smaller than a second threshold; or determining, by the first device, that the L-LTF sequence corresponding to the signal frame is not the target L-LTF sequence when a ratio between the absolute value of the second channel estimate and the absolute value of the third channel estimate is equal to or greater than the second threshold.

5. The method of claim 4, comprising:

6. 1. A method for signal identification, said method comprising: marking, by a second device, the amplitude and / or phase of N subcarrier elements in a legacy long training field (L-LTF) sequence corresponding to a signal frame, wherein the L-LTF sequence corresponding to the signal frame includes M subcarrier elements, M and N are positive integers, M>1, 1≦N≦M; sending, by the second device, the signal frame to a first device; A signal identification method comprising:

7. 7. The method of claim 6, wherein when the N subcarrier elements include subcarriers with consecutive sequence numbers, the amplitude and phase change values ​​of subcarrier elements with adjacent sequence numbers are different.

8. 1. A communications device, the device comprising: a processing module and a transceiver module; the transceiver module is configured to receive signal frames; the processing module is configured to perform channel estimation based on a legacy long training field (L-LTF) sequence corresponding to the signal frame to obtain a first channel estimate, the first channel estimate including a channel estimate corresponding to M subcarrier elements in the L-LTF sequence corresponding to the signal frame; the processing module is further configured to determine whether the L-LTF sequence corresponding to the signal frame is a target L-LTF sequence based on the first channel estimate and mark information of N subcarrier elements, the mark information of the N subcarrier elements including sequence numbers of the N subcarrier elements and amplitude and / or phase change values ​​corresponding to the N subcarrier elements, M and N are positive integers, M>1, 1≦N≦M.

9. The processing module is further configured to determine whether the L-LTF sequence corresponding to the signal frame is a target L-LTF sequence based on the first channel estimate and mark information of N subcarrier elements. the processing module is configured to determine a first subcarrier element and a second subcarrier element based on the sequence numbers of the N subcarrier elements, the first subcarrier element being a subcarrier element whose subcarrier element sequence number corresponds to the sequence number of the N subcarrier elements in the L-LTF sequence corresponding to the signal frame, and the second subcarrier element being a subcarrier element whose subcarrier element sequence number is adjacent to the sequence number of the N subcarrier elements in the L-LTF sequence corresponding to the signal frame; The processing module is further configured to determine whether the L-LTF sequence corresponding to the signal frame is the target L-LTF sequence based on a channel estimate corresponding to the first subcarrier element, a channel estimate corresponding to the second subcarrier element, and the amplitude and / or phase change values ​​corresponding to the N subcarrier elements in the first channel estimate.

9. The apparatus of claim 8, comprising:

10. The processing module is further configured to determine whether the L-LTF sequence corresponding to the signal frame is the target L-LTF sequence based on a channel estimate corresponding to the first subcarrier element, a channel estimate corresponding to the second subcarrier element, and the amplitude and / or phase change values ​​corresponding to the N subcarrier elements in the first channel estimate; The processing module is configured to determine a second channel estimate based on the channel estimate corresponding to the first subcarrier element, the channel estimate corresponding to the second subcarrier element, and the amplitude and / or phase change values ​​corresponding to the N subcarrier elements, wherein the second channel estimate satisfies a first relationship: [Equation 6] where F_f is a sequence number of the i-th subcarrier element in the second subcarrier element, and F_f is a sequence number of the i-th subcarrier element in the N subcarrier elements. １２ (i) = f １２ (i) or When the sequence number of the i-th subcarrier element in the second subcarrier element is the same as the sequence number of the subcarrier element in the N subcarrier elements, [Equation 7] where f ２ is the second channel estimate, and f １１ (i) is a channel estimate corresponding to the i-th subcarrier element in the first subcarrier element, and T ｃｏｌｏｒ (i) is an amplitude and / or phase change value corresponding to the i-th subcarrier element among the N subcarrier elements; １２ (i) is a channel estimate corresponding to the i-th subcarrier element in the second subcarrier element, and T ｃｏｌｏｒ (·) is an amplitude and / or phase change value corresponding to a subcarrier element in the N subcarrier elements, the sequence number of which is the same as the sequence number of the i-th subcarrier element in the second subcarrier elements, the sequence number of the i-th subcarrier element in the first subcarrier elements is the same as the sequence number of the i-th subcarrier element in the N subcarrier elements, and the i-th subcarrier element in the second subcarrier elements is a subcarrier element whose sequence number is adjacent to the sequence number of the i-th subcarrier element in the N subcarrier elements, where i is a positive integer and 1≦i≦N; the processing module is further configured to determine that the L-LTF sequence corresponding to the signal frame is the target L-LTF sequence when the absolute value of the second channel estimate is less than a first threshold; or The processing module is further configured to determine that the L-LTF sequence corresponding to the signal frame is not the target L-LTF sequence when an absolute value of the second channel estimate is greater than or equal to the first threshold.

10. The apparatus of claim 9, comprising:

11. The processing module is further configured to determine whether the L-LTF sequence corresponding to the signal frame is the target L-LTF sequence based on a channel estimate corresponding to the first subcarrier element, a channel estimate corresponding to the second subcarrier element, and the amplitude and / or phase change values ​​corresponding to the N subcarrier elements in the first channel estimate; The processing module is configured to determine a second channel estimate and a third channel estimate based on the channel estimate corresponding to the first subcarrier element, the channel estimate corresponding to the second subcarrier element, and the amplitude and / or phase change values ​​corresponding to the N subcarrier elements, wherein the second channel estimate is determined according to a second relationship: [Equation 8] and the third channel estimate satisfies a third relationship: [Equation 9] where F_f is a sequence number of the i-th subcarrier element in the second subcarrier element, and F_f is a sequence number of the i-th subcarrier element in the N subcarrier elements. １２ (i) = f １２ (i) or When the sequence number of the i-th subcarrier element in the second subcarrier element is the same as the sequence number of the subcarrier element in the N subcarrier elements, [Equation 10] where: f ２ is the second channel estimate, and f ３ is the third channel estimate, and f １１ (i) is a channel estimate corresponding to the i-th subcarrier element in the first subcarrier element, and T ｃｏｌｏｒ (i) is an amplitude and / or phase change value corresponding to the i-th subcarrier element among the N subcarrier elements; １２ (i) is a channel estimate corresponding to the i-th subcarrier element in the second subcarrier element, and T ｃｏｌｏｒ (·) is an amplitude and / or phase change value corresponding to a subcarrier element in the N subcarrier elements, the sequence number of which is the same as the sequence number of the i-th subcarrier element in the second subcarrier elements, the sequence number of the i-th subcarrier element in the first subcarrier elements is the same as the sequence number of the i-th subcarrier element in the N subcarrier elements, and the i-th subcarrier element in the second subcarrier elements is a subcarrier element whose sequence number is adjacent to the sequence number of the i-th subcarrier element in the N subcarrier elements, where i is a positive integer and 1≦i≦N; The processing module is further configured to determine whether the L-LTF sequence corresponding to the signal frame is the target L-LTF sequence based on the second channel estimate and the third channel estimate.

10. The apparatus of claim 9, comprising:

12. The processing module is further configured to determine whether the L-LTF sequence corresponding to the signal frame is the target L-LTF sequence based on the second channel estimate and the third channel estimate. the processing module is further configured to determine that the L-LTF sequence corresponding to the signal frame is the target L-LTF sequence when a ratio between an absolute value of the second channel estimate and an absolute value of the third channel estimate is smaller than a second threshold; or The processing module is further configured to determine whether the L-LTF sequence corresponding to the signal frame is the target L-LTF sequence based on the second channel estimate and the third channel estimate, and to determine that the L-LTF sequence corresponding to the signal frame is not the target L-LTF sequence when a ratio between an absolute value of the second channel estimate and an absolute value of the third channel estimate is equal to or greater than the second threshold. The apparatus of claim 11 , comprising:

13. 1. A communications device, the device comprising: a processing module and a transceiver module; the processing module is configured to mark the amplitude and / or phase of N subcarrier elements in a legacy long training field (L-LTF) sequence corresponding to a signal frame, the L-LTF sequence corresponding to the signal frame including M subcarrier elements, M and N being positive integers, M>1, 1≦N≦M; The communication apparatus, wherein the transceiver module is configured to transmit the signal frame to a first device.

14. 14. The apparatus of claim 13, wherein when the N subcarrier elements include subcarriers with consecutive sequence numbers, amplitude and phase change values ​​of subcarrier elements with adjacent sequence numbers are different.

15. 1. A communications device comprising: a processor, the processor coupled to a memory; the memory is configured to store a computer program; A communication device, wherein the processor is configured to execute the computer program stored in the memory to enable the communication device to perform the method of any one of claims 1 to 7.

16. 8. A computer readable storage medium storing a computer program or instructions, the computer program or instructions being enabled to perform the method of any one of claims 1 to 7 when the computer program or instructions are run on a computer.

17. 8. A computer program product comprising a computer program or instructions, which when said computer program or said instructions are run on a computer, enables said computer to carry out the method according to any one of claims 1 to 7.

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