CN107529354B

CN107529354B - Data transmission method and transmission device

Info

Publication number: CN107529354B
Application number: CN201580078520.7A
Authority: CN
Inventors: 刘晟
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2015-03-31
Filing date: 2015-03-31
Publication date: 2020-02-14
Anticipated expiration: 2035-03-31
Also published as: WO2016154951A1; CN107529354A

Abstract

The embodiment of the invention provides a data transmission method applied to a Wireless Local Area Network (WLAN), which comprises the following steps: generating a physical layer packet, wherein the physical layer packet comprises a traditional signaling field L-SIG and a first Orthogonal Frequency Division Multiplexing (OFDM) symbol behind the L-SIG, the L-SIG and the OFDM symbol comprise a plurality of data subcarriers in a frequency domain, and signals on the data subcarriers of the OFDM symbol are obtained by multiplying signals on the data subcarriers at the positions corresponding to the L-SIG by elements at the positions corresponding to the characteristic sequences; transmitting a physical layer packet containing the L-SIG and the OFDM symbol. The embodiment of the invention also provides a corresponding data transmission device. By applying the method and the device provided by the embodiment of the invention, the identification of 11ax physical layer packets and the enhancement of L-SIG detection performance can be realized.

Description

Data transmission method and transmission device

Technical Field

The present invention belongs to the field of communication technology, and in particular, to a data transmission method and a data transmission device.

Background

The existing Wireless Local Area Network (WLAN) standard based on OFDM (Orthogonal Frequency Division Multiplexing, chinese) technology is composed of versions of 802.11a, 802.11n, 802.11ac, etc. which are evolved gradually, the current IEEE (Institute of electrical and Electronic Engineers, chinese) 802.11 organization has started standardization work of a new generation WLAN standard 802.11ax called HEW (High Efficiency WLAN), and by introducing OFDMA (Orthogonal Frequency-Division Multiplexing Access, Orthogonal Frequency Division Multiplexing multiple Access) technology, 802.11ax can further improve the transmission performance of WLAN in a dense user scene.

However, existing WLAN devices do not effectively distinguish between 802.11ax packets, 802.11ac packets, and 802.11n packets.

Disclosure of Invention

In view of this, the present invention provides a method and an apparatus for data transmission in a wireless local area network, which are used to solve the problem that the existing WLAN device cannot effectively distinguish 802.11ax packets, 802.11ac packets, and 802.11n packets.

In a first aspect, an embodiment of the present invention provides a data transmission method applied to a wireless local area network WLAN, including:

generating a physical layer packet, wherein the physical layer packet includes a legacy signaling field L-SIG and a first Orthogonal Frequency Division Multiplexing (OFDM) symbol after the L-SIG, the L-SIG and the OFDM symbol include a plurality of data subcarriers in a frequency domain, and a signal on a data subcarrier of the OFDM symbol is obtained by multiplying a signal on a data subcarrier at a position corresponding to the L-SIG by an element at a position corresponding to a characteristic sequence;

transmitting the physical layer packet containing the L-SIG and the OFDM symbol.

In a first possible implementation manner of the first aspect, the signal on the L-SIG data subcarrier is a binary phase shift keying BPSK modulation symbol.

With reference to the first aspect or the first possible implementation manner of the first aspect, in a second possible implementation manner of the first aspect, the number of the L-SIG and the data subcarriers of the OFDM symbol is 48 or 52.

With reference to the first aspect and the foregoing implementation manner, in a third possible implementation manner of the first aspect, the feature sequence is a sequence consisting of +1 and-1, and a protocol version corresponding to the feature sequence is an 802.11ax protocol or a subsequent evolution protocol.

With reference to the first aspect or the third possible implementation manner of the first aspect, in a fourth possible implementation manner of the first aspect, the length of the signature sequence is the same as the number of data subcarriers of the L-SIG.

In a second aspect, an embodiment of the present invention provides a data transmission method applied to a wireless local area network WLAN, including:

receiving a physical layer packet;

analyzing the physical layer packet specifically includes: multiplying the signals on the data subcarriers of the first orthogonal frequency division multiplexing OFDM symbol after the traditional signaling field L-SIG in the physical layer packet by each element of the characteristic sequence one by one, and performing cross-correlation processing on the signals obtained after multiplication and the signals on the data subcarriers of the L-SIG;

determining a protocol version of the physical layer packet specifically includes: and if the result of the cross-correlation processing exceeds a first threshold, determining that the physical layer packet is a physical layer packet of a protocol version corresponding to the characteristic sequence.

With reference to the second aspect, in a first possible implementation manner of the second aspect, the number of data subcarriers of the L-SIG and a first OFDM symbol after the L-SIG is 48 or 52.

With reference to the second aspect, in a second possible implementation manner of the second aspect, the feature sequence is a sequence consisting of +1 and-1, and a protocol version corresponding to the feature sequence is an 802.11ax protocol or a subsequent evolution protocol.

With reference to the second aspect or the second possible implementation manner of the second aspect, in a third possible implementation manner of the second aspect, the length of the signature sequence is the same as the number of data subcarriers of the L-SIG.

In a third aspect, an embodiment of the present invention provides a data transmission apparatus applied to a wireless local area network WLAN, including:

a processing unit, configured to generate a physical layer packet, where the physical layer packet includes a legacy signaling field L-SIG and a first orthogonal frequency division multiplexing, OFDM, symbol after the L-SIG, where the L-SIG and the OFDM symbol include a plurality of data subcarriers in a frequency domain, and a signal on a data subcarrier of the OFDM symbol is obtained by multiplying a signal on a data subcarrier at a position corresponding to the L-SIG by an element at a position corresponding to a signature sequence;

a transceiving unit configured to transmit the physical layer packet including the L-SIG and the OFDM symbol. With reference to the third aspect, in a first possible implementation manner of the third aspect, the signal on the L-SIG data subcarrier in the physical layer packet generated by the processing unit is a binary phase shift keying BPSK modulation symbol.

With reference to the third aspect and the first possible implementation manner of the third aspect, in a second possible implementation manner of the third aspect, the number of data subcarriers of the L-SIG and the OFDM symbol in the physical layer packet generated by the processing unit is 48 or 52.

With reference to the third aspect and the foregoing implementation manner of the third aspect, in a third possible implementation manner of the third aspect, the feature sequence is a sequence composed of +1 and-1, and a protocol version corresponding to the feature sequence is an 802.11ax protocol or a subsequent evolution protocol.

With reference to the third aspect or the third possible implementation manner of the third aspect, in a fourth possible implementation manner of the third aspect, the length of the signature sequence is the same as the number of data subcarriers of the L-SIG.

In a fourth aspect, an embodiment of the present invention provides a data transmission apparatus applied to a wireless local area network WLAN, including:

a transceiving unit for receiving a physical layer packet;

a processing unit, configured to parse the physical layer packet, and specifically include: multiplying the signals on the data subcarriers of the first orthogonal frequency division multiplexing OFDM symbol after the traditional signaling field L-SIG in the physical layer packet by each element of the characteristic sequence one by one, and performing cross-correlation processing on the signals obtained after multiplication and the signals on the data subcarriers of the L-SIG;

a processing unit, configured to determine a protocol version of the physical layer packet, and specifically include: and if the result of the cross-correlation processing exceeds a first threshold, determining that the physical layer packet is a physical layer packet of a protocol version corresponding to the characteristic sequence.

With reference to the fourth aspect, in a first possible implementation manner of the fourth aspect, the number of data subcarriers of the L-SIG and the first OFDM symbol after the L-SIG in the data packet parsed by the processing unit is 48 or 52.

With reference to the fourth aspect, in a second possible implementation manner of the fourth aspect, the feature sequence is a sequence consisting of +1 and-1, and a protocol version corresponding to the feature sequence is an 802.11ax protocol or a subsequent evolution protocol.

With reference to the fourth aspect or the second possible implementation manner of the fourth aspect, in a third possible implementation manner of the fourth aspect, the length of the signature sequence is the same as the number of data subcarriers of the L-SIG.

In the data transmission process of the wireless local area network, the signal on the data subcarrier of the first OFDM symbol after the L-SIG is obtained by multiplying the signal on the data subcarrier corresponding to the L-SIG and the element corresponding to the characteristic sequence, and the signal is not periodically repeated in the L-SIG in both the time domain and the frequency domain, so that the problem of misjudgment caused by the influence of periodic interference signals is solved. Meanwhile, for the protocol of the version after 802.11ax (i.e. the protocol of the subsequent version), only the characteristic sequence different from the specific characteristic sequence of 802.11ax needs to be adopted. Preferably, the characteristic sequence with small cross-correlation with the specific characteristic sequence of 802.11ax can be adopted, so that the automatic detection of a new version protocol can be realized in the same way, and the compatibility problem among different standards is solved. Therefore, the embodiment of the invention ensures the identification of 11ax physical layer packets and the enhancement of the detection performance of the L-SIG.

Drawings

Fig. 1 is an application scenario diagram of an embodiment of the present invention.

Fig. 2 is a block diagram of a physical layer packet in the existing WLAN standard.

Fig. 3 is a constellation diagram for BPSK and QBPSK modulation.

Fig. 4 is a physical layer packet structure diagram of 802.11 ax.

Fig. 5 is a block diagram of a WLAN physical layer packet in embodiment 1 of the present invention.

FIG. 6 is a flowchart of the method of embodiment 1 of the present invention.

FIG. 7 is a generation process of a scrambled RL-SIG field.

Fig. 8 is a schematic diagram of automatic detection of 802.11ax physical layer packets in embodiment 1 of the present invention.

Fig. 9 is a logical structure diagram of a station in embodiment 2 of the present invention.

Fig. 10 is a logical structure diagram of a station according to embodiment 3 of the present invention.

Fig. 11 is a physical structure diagram of a transmitting station in embodiment 4 of the present invention.

Fig. 12 is a physical structure diagram of a receiving station in embodiment 4 of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention are described in further detail below with reference to the accompanying drawings. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. It will be understood by those skilled in the art, however, that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, components, circuits, and the like have not been described in detail so as not to unnecessarily obscure the embodiments. It is to be understood that the embodiments described below are only some of the embodiments of the present invention, and not all of them. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The embodiment of the invention can be applied to the WLAN, and the standard adopted by the WLAN is IEEE802.11 series at present. The WLAN may include a plurality of Basic Service Sets (BSS), where a network node in a BSS is a Station (STA), and the Station includes an Access Point (AP) and a Non-Access Point (Non-AP STA). Each basic service set may include one AP and a plurality of Non-AP STAs associated with the AP.

And the access point type station is also called as a wireless access point or a hot spot, and the like. The AP is an access point for a mobile subscriber to enter a wired network, and is mainly deployed in a home, a building, and a campus, and typically has a coverage radius of several tens of meters to hundreds of meters, and may be deployed outdoors. The AP acts as a bridge connecting the network and the wireless network, and mainly functions to connect the wireless network clients together and then to access the wireless network to the ethernet. Specifically, the AP may be a terminal device or a network device with a WiFi (Wireless Fidelity, chinese) chip. Optionally, the AP may be a device supporting 802.11ax standard, and further optionally, the AP may be a device supporting multiple WLAN standards such as 802.11ac, 802.11n, 802.11g, 802.11b, and 802.11 a.

A Non-Access Point (Non-AP STA) may be a wireless communication chip, a wireless sensor, or a wireless communication terminal. For example: the mobile phone supporting the WiFi communication function, the tablet computer supporting the WiFi communication function, the set top box supporting the WiFi communication function, the smart television supporting the WiFi communication function, the smart wearable device supporting the WiFi communication function, the vehicle-mounted communication device supporting the WiFi communication function and the computer supporting the WiFi communication function. Optionally, the station may support an 802.11ax system, and further optionally, the station supports multiple WLAN systems such as 802.11ac, 802.11n, 802.11g, 802.11b, and 802.11 a.

Fig. 1 is a system diagram of a typical WLAN deployment scenario, including an AP in communication with STA1, STA2, and STA3, and 3 STAs.

For better understanding of the physical layer packet structure of 802.11ax, fig. 2 shows the physical layer packet structures of 802.11a, 802.11n and 802.11ac in the prior art, wherein the initial parts of them are all traditional preambles (i.e. fields composed of traditional Short Training field (L-STF), traditional Long Training field (L-LTF) and traditional signaling field (L-SIG). The 802.11a physical layer packets are followed by the legacy preamble as the data field, and the 802.11n and 802.11ac physical layer packets are between the legacy preamble and the data field, with the addition of a protocol specific preamble. The protocol specific preamble of the 802.11n physical layer packet is composed of a High throughput signaling field (HT-SIG for short), a High throughput short Training field (HT-STF for short) and a High throughput long Training field (HT-LTF for short); the protocol specific preamble of the 802.11ac physical layer packet consists of a Very High Throughput signaling A field (VHT-SIG-A for Short), a Very High Throughput Short Training field (VHT-STF for Short), a Very High Throughput Long Training field (VHT-LTF for Short), and a Very High Throughput signaling B field (VHT-SIG-B for Short).

In the WLAN standards based on the OFDM technology, such as 802.11a, 802.11n, 802.11ac, etc., the basic unit of each physical layer packet is an OFDM symbol, and each OFDM symbol includes a Cyclic Prefix (CP) with a length of 4 microseconds, typically 0.8 microseconds. As shown in fig. 2, the L-SIG has only one OFDM symbol, and the HT-SIG and VHT-SIG-a each include two OFDM symbols, each OFDM symbol includes 64 subcarriers in the frequency domain, where 48 data subcarriers are used for carrying modulation symbols of corresponding physical layer control information. In 802.11n, the modulation symbols carried on the data subcarriers of two OFDM symbols of HT-SIG are modulated by Quadrature Binary Phase Shift Keying (QBPSK); wherein, QBPSK modulation is rotated by 90 degrees compared with the general Binary Phase Shift Keying (BPSK for short) constellation, the BPSK and QBPSK modulated constellation is shown in fig. 3, where the drawing on the left side of fig. 3 is BPSK modulation, and the drawing on the right side of fig. 3 is QBPSK modulation.

Since the two OFDM symbols of 802.11a following the L-SIG do not employ QBPSK modulation, the receiver of 802.11n can distinguish the physical layer packets of 802.11n and 802.11a according to the characteristics of the first OFDM symbol following the L-SIG of the received WLAN physical layer packet, i.e., whether the modulation symbols carried on its 48 data subcarriers are QBPSK modulated. In 802.11ac, the modulation symbols carried on the data subcarriers of the second OFDM symbol of VHT-SIG-a are also QBPSK modulated, but the modulation symbols carried on the data subcarriers of the first OFDM symbol are BPSK modulated, so that the 802.11n receiver does not treat the physical layer packet of 802.11ac as a physical layer packet of 802.11n, whereas the 802.11ac receiver can distinguish the physical layer packets of 802.11ac and 802.11a according to whether the modulation symbols carried on the 48 data subcarriers of the first OFDM symbol after the received WLAN physical layer packet L-SIG are QBPSK modulated, and distinguish the physical layer packets of 802.11ac and 802.11n according to whether the modulation symbols carried on the 48 data subcarriers of the second OFDM symbol after the received WLAN physical layer packet L-SIG are BPSK modulated.

Fig. 4 shows an 802.11ax physical layer packet structure, where the first part is also a legacy preamble, that is, a field composed of L-STF, L-LTF, and L-SIG, and the last part is a data field, a 802.11ax protocol-specific preamble, that is, an HEW preamble, is located between the legacy preamble and the data field, a first field of the HEW preamble is a high efficiency signaling a field (in english: high efficiency Signal-a field, for short, HE-SIG-a), the HE-SIG-a is composed of at least one OFDM symbol with a length of 4 microseconds, a first OFDM symbol after L-SIG is an OFDM symbol with a length of 4 microseconds, and a second OFDM symbol after L-SIG is a first OFDM symbol of HE-SIG-a.

To achieve automatic detection of 802.11ax physical layer packets, it is first avoided that a receiver of 802.11n or 802.11ac misinterprets an 802.11ax physical layer packet as an 802.11n or 802.11ac physical layer packet, for which purpose the first and second OFDM symbols after the 802.11ax physical layer packet L-SIG are both BPSK modulated, as shown in fig. 4. Meanwhile, in order for the 802.11ax receiver to correctly identify the 802.11ax physical layer packet and reduce the false positive probability, two different solutions have been proposed in the prior art.

As described above, the length of the L-SIG is one OFDM symbol, and in a first existing scheme, a first OFDM symbol after the L-SIG is a repetition of the L-SIG, that is, the first OFDM symbol after the L-SIG is the same as the OFDM symbol of the L-SIG, and is referred to as RL-SIG (english: Repeated L-SIG). The 802.11ax receiver can correctly identify the 802.11ax physical layer packet according to the repeated characteristic, and meanwhile, because the RL-SIG is the repetition of the L-SIG, the receiver can combine the signals on the data subcarriers of the two OFDM symbols, thereby obtaining the gain of 3dB Signal to noise power Ratio (SNR) and improving the reliability of the L-SIG transmission.

The first OFDM symbol after L-SIG in the second prior art scheme is a signature symbol (english): SignatureSymbol), among the information bits carried by the OFDM symbol, a signature sequence of 802.11ax is used to identify the physical layer packet of 802.11ax, for example, if the OFDM symbol includes 48 data subcarriers, if convolutional coding with a coding rate of 1/2 is adopted, because each data subcarrier carries BPSK modulation symbols, 48 × 1/2 ═ 24 bits can be transmitted, 18 information bits can be transmitted in total by subtracting the 6 tail bits generated by convolutional coding, and a signature sequence with a length of 10 bits can be used to identify the physical layer packet of 802.11 ax. The probability of a non-802.11 ax physical layer packet transmitting the signature sequence in the first OFDM symbol right after L-SIG is 1/2¹⁰0.1%, the probability of misinterpreting physical layer packets other than 802.11ax as physical layer packets of 802.11ax can be further reduced by using a longer (no more than 18 bits) signature sequence.

However, both prior art solutions have certain problems. Among them, the main problems of the first existing solution are: the 5GHz frequency band where the WLAN is located is an unlicensed frequency spectrum, other devices except the WLAN may use the frequency band, or out-of-band leakage of other wireless devices may enter the frequency band, and many of these interference signals have periodicity, and the first existing scheme is easily affected by the periodic interference signals by using the repetition characteristics of RL-SIG and L-SIG, so as to increase the risk of misinterpreting a physical layer packet other than 802.11ax as a physical layer packet of 802.11 ax; in addition, the first existing scheme does not consider the support of the new version protocol after 802.11ax, that is, the new version protocol needs to redesign a new way to automatically detect the physical layer packet of the new version protocol, and in contrast, the second existing scheme only needs to allocate a signature sequence different from the 802.11ax to the new version protocol to distinguish the 802.11ax from the new version protocol. However, compared with the first prior art, the second prior art cannot obtain the SNR gain caused by combining the L-SIG and the RL-SIG, and cannot ensure reliable transmission of the L-SIG outdoors and under low SNR.

Example 1

Embodiment 1 of the present invention provides a data transmission method applied to a WLAN, where the method may be applied to a station, for example: AP and STA1 in fig. 1-STA3, which may support next generation WLAN standards such as: 802.11ax format. Fig. 6 is an interaction diagram of the data transmission method, and the specific steps are as follows:

step 1: generating a physical layer packet, wherein the physical layer packet comprises a legacy signaling field L-SIG and a first Orthogonal Frequency Division Multiplexing (OFDM) symbol after the L-SIG, the L-SIG and the OFDM symbol comprise a plurality of data subcarriers in a frequency domain, and a signal on the data subcarrier of the OFDM symbol is obtained by multiplying a signal on the data subcarrier at a position corresponding to the L-SIG by an element at a position corresponding to a characteristic sequence.

Step 2: and transmitting a physical layer packet, wherein the first station transmits the physical layer packet containing the L-SIG and the OFDM symbol.

And step 3: a physical layer packet is received.

And 4, step 4: analyzing the physical layer packet specifically includes: and multiplying the signals on the data subcarriers of the first orthogonal frequency division multiplexing OFDM symbol after the traditional signaling field L-SIG in the physical layer packet by each element of the characteristic sequence one by one, and performing cross-correlation processing on the signals obtained after multiplication and the signals on the data subcarriers of the L-SIG.

And 5: determining a protocol version of a physical layer packet, specifically comprising: and if the result of the cross-correlation processing exceeds a first threshold, the second station determines that the physical layer packet is a physical layer packet of a protocol version corresponding to the characteristic sequence.

It should be noted that the cross-correlation processing in step 104 is a common means in signal processing, and is a signal processing method for determining the similarity between two signals. The first threshold in step 105 is determined by a compromise between the false positive probability and the false negative probability, for example, if the maximum value of the cross-correlation is 1, the threshold may be 0.95.

It should be noted that a possible physical layer packet structure conforming to the next generation WLAN protocol (e.g. 802.11ax) proposed by the present invention is shown in fig. 5, where the initial part is a legacy preamble, i.e. a field composed of L-STF, L-LTF and L-SIG, and the L-SIG is followed by the first OFDM symbol after the L-SIG, which is called a scrambled RL-SIG field, which is an OFDM symbol with a length of 4 microseconds, and a CP of 0.8 microseconds. The scrambled RL-SIG field is added with a tag specific to the protocol version by using the embodiment of the present invention, and the transmitted information bits are the same as the information bits transmitted by the L-SIG field, and the modulation symbols carried on the data subcarriers are BPSK modulated. The scrambled RL-SIG field is followed by the next generation WLAN protocol version specific preamble, which is preceded by an OFDM symbol (i.e., the second OFDM symbol after L-SIG) with a 4 microsecond CP of 0.8 microseconds, and the modulation symbols carried on the data subcarriers of the OFDM symbol are also BPSK modulated. The next generation WLAN protocol version specific preamble is followed by a data field.

It should be noted that, in step 101, the process of the first station generating the first OFDM symbol (i.e., scrambled RL-SIG) after the L-SIG in the physical layer packet is shown in fig. 7.

Optionally, the signal on the L-SIG data subcarrier is a binary phase shift keying BPSK modulation symbol, and the number of the L-SIG and the data subcarriers of the OFDM symbol is 48 or 52.

Optionally, the feature sequence is a sequence formed by +1 and-1, and a protocol version corresponding to the feature sequence includes an 802.11ax protocol or a subsequent evolution protocol.

Optionally, the length of the signature sequence is the same as the number of data subcarriers of the L-SIG.

Specifically, the generation process of the scrambled RL-SIG in the physical layer packet includes the following steps.

Step a: the information bits of the L-SIG are first channel coded, typically using convolutional coding at a coding rate of 1/2.

Step b: the encoded bit sequence is sequentially subjected to a BPSK constellation mapping module to generate K BPSK modulation symbols and respectively correspond to K data subcarriers, typically, K is 48 or 52, when K is 48, the information bit length of L-SIG after 6-bit tail bits are subtracted is 48/2-6-18 bits, and when K is 52, the information bit length of L-SIG after 6-bit tail bits are subtracted is 52/2-6-20 bits.

Step c-1: the generated K BPSK modulation symbols directly form a time domain signal with a length of 3.2 microseconds through 64-point Inverse Fast Fourier Transform (IFFT), and then add a CP of 0.8 microseconds, that is, generate an L-SIG field with a length of 4 microseconds.

Step c-2: multiplying L (L is not more than K) of the generated K BPSK modulation symbols with each element of a protocol version specific characteristic sequence with the length of L respectively, wherein each element of the characteristic sequence is +1 or-1, then forming a time domain signal with the length of 3.2 microseconds through a 64-point IFFT, and adding a CP of 0.8 microseconds to generate a scrambled RL-SIG field with the length of 4 microseconds.

It should be noted that the process of the second station parsing the physical layer packet and determining the protocol version of the physical layer packet in steps 104 and 105 is shown in fig. 8, and specifically, the steps are as follows:

step a: after receiving a time domain signal of a first OFDM symbol after L-SIG of a WLAN physical layer packet, the second station removes the CP, and transforms the time domain signal to a frequency domain through Fast Fourier Transform (FFT) with 64 points.

Step b: the respective elements of the 802.11ax specific signature sequence are multiplied with the signals on the corresponding L data subcarriers.

Step c: and repeatedly detecting signals on K data subcarriers of the OFDM symbol and signals on K data subcarriers of the L-SIG, namely judging whether the signals on the K data subcarriers of the OFDM symbol are the same as the signals on the K data subcarriers of the L-SIG or not, and if the signals on the K data subcarriers of the OFDM symbol are successful, determining that the physical layer packet is an 802.11ax physical layer packet. Typically, the duplicate detection may be implemented by cross-correlating signals on K data subcarriers of the OFDM symbol with signals on K data subcarriers of the L-SIG, and if a result of the cross-correlation process exceeds a predetermined threshold, the second station determines that the physical layer packet is an 802.11ax physical layer packet. And simultaneously, after signals on K data subcarriers of the OFDM symbol are combined with signals on K data subcarriers of the L-SIG, BPSK demodulation and channel decoding are carried out, and information bits of the L-SIG are obtained.

It should be noted that, since the BPSK symbol is either +1 or-1, and the protocol version specific signature sequence is composed of +1 and-1, therefore, the signals obtained by multiplying L of the K generated BPSK modulation symbols by the elements of the protocol version-specific signature sequence are still BPSK modulated, and thus, in the physical layer packet structure shown in fig. 5, the modulation symbols carried on the data subcarriers of the first OFDM symbol after L-SIG (i.e., the scrambled RL-SIG) are still BPSK modulated, while the modulation symbols carried on the data subcarriers of the second OFDM symbol after L-SIG (i.e. the first OFDM symbol of the protocol version specific preamble) are also BPSK modulated, it is therefore possible to avoid the receiver of 802.11n or 802.11ac misjudging the physical layer packet as a physical layer packet of 802.11n or 802.11 ac.

It should be noted that, in the embodiment of the present invention, the first station plays a role of a transmitter, and the second station plays a role of a receiver. Both the first station and the second station may be access points AP or stations STA of the WLAN.

Example 2

Correspondingly, fig. 9 is a schematic block diagram of a data transmission apparatus in a wireless local area network according to embodiment 2 of the present invention. The data transmission means are for example stations or dedicated circuits or chips implementing the relevant functions. The data transmission apparatus 1100 shown in fig. 9 includes a processing unit 1101 and a transceiving unit 1102. For example, the channel indication apparatus 1100 may be an AP or STA1-STA3 shown in fig. 1. The station in embodiment 2 plays the role of a sender.

A processing unit 1101, configured to generate a physical layer packet, where the physical layer packet includes a legacy signaling field L-SIG and a first orthogonal frequency division multiplexing OFDM symbol after the L-SIG, where the L-SIG and the OFDM symbol include a plurality of data subcarriers in a frequency domain, and a signal on a data subcarrier of the OFDM symbol is obtained by multiplying a signal on a data subcarrier at a position corresponding to the L-SIG by an element at a position corresponding to a signature sequence;

a transceiving unit 1102 configured to transmit the physical layer packet including the L-SIG and the OFDM symbol.

Optionally, the signal on the L-SIG data subcarrier in the physical layer packet generated by the processing unit is a binary phase shift keying BPSK modulation symbol.

Optionally, the number of data subcarriers of the OFDM symbol and L-SIG in the physical layer packet generated by the processing unit is 48 or 52.

Optionally, the feature sequence is a sequence formed by +1 and-1, and a protocol version corresponding to the feature sequence is an 802.11ax protocol or a subsequent evolution protocol.

In the data transmission process of the wireless local area network, the processing unit multiplies the signal on the data subcarrier at the position corresponding to the L-SIG by the element at the position corresponding to the characteristic sequence to obtain the signal on the data subcarrier of the first OFDM symbol after the L-SIG. Meanwhile, for the protocol of the version after 802.11ax (i.e. the protocol of the subsequent version), only the characteristic sequence different from the specific characteristic sequence of 802.11ax needs to be adopted. Preferably, the characteristic sequence with small cross-correlation with the specific characteristic sequence of 802.11ax can be adopted, so that the automatic detection of a new version protocol can be realized in the same way, and the compatibility problem among different standards is solved. Therefore, the embodiment of the invention ensures the identification of 11ax physical layer packets and the enhancement of the detection performance of the L-SIG.

Example 3

Correspondingly, fig. 10 is a schematic block diagram of a data transmission apparatus in a wireless local area network according to embodiment 3 of the present invention. The data transmission means are for example stations or dedicated circuits or chips implementing the relevant functions. The data transmission apparatus 1200 shown in fig. 10 includes a processing unit 1201 and a transceiving unit 1202. For example, the channel indication apparatus 1200 may be an AP or STA1-STA3 shown in fig. 1. The station in embodiment 3 plays the role of a receiver.

A transceiving unit 1201, configured to receive a physical layer packet;

the processing unit 1202 is configured to parse the physical layer packet, and specifically includes: multiplying the signals on the data subcarriers of the first orthogonal frequency division multiplexing OFDM symbol after the traditional signaling field L-SIG in the physical layer packet by each element of the characteristic sequence one by one, and performing cross-correlation processing on the signals obtained after multiplication and the signals on the data subcarriers of the L-SIG;

a processing unit 1202, configured to determine a protocol version of the physical layer packet, specifically including: and if the result of the cross-correlation processing exceeds a first threshold, determining that the physical layer packet is a physical layer packet of a protocol version corresponding to the characteristic sequence.

Optionally, the number of data subcarriers of the L-SIG in the data packet parsed by the processing unit and the first orthogonal frequency division multiplexing OFDM symbol after the L-SIG is 48 or 52.

In the data transmission process of the wireless local area network, a processing unit multiplies signals on data subcarriers of a first orthogonal frequency division multiplexing OFDM symbol after a traditional signaling field L-SIG in a physical layer packet received by a transceiving unit by each element of a characteristic sequence one by one, and performs cross-correlation processing on the signals obtained after multiplication and the signals on the data subcarriers of the L-SIG; and if the result of the cross-correlation processing exceeds a first threshold, determining that the physical layer packet is a physical layer packet of a protocol version corresponding to the characteristic sequence. By the mode, the identification of 11ax physical layer packets and the enhancement of the detection performance of the L-SIG are ensured.

Example 4

Accordingly, another embodiment provides a data transmission apparatus comprising a processor for generating or processing (transmitting or receiving) a new 11ax physical layer packet (as shown in fig. 5). For a specific transmission method, reference may be made to the methods described in the foregoing embodiments (as shown in fig. 6), and details are not repeated here. The processor may be a general purpose processor, a digital signal processor, an application specific integrated circuit, a field programmable gate array or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or the like that implement or perform the methods, steps, and logic blocks disclosed in embodiments of the present invention. A general purpose processor may be a microprocessor or any conventional processor or the like. The steps of a method disclosed in connection with the embodiments of the present invention may be directly implemented by a hardware processor, or may be implemented by a combination of hardware and software modules in the processor. It is easy to understand that, the processing device for resource indication may be located at the access point when specifically transmitting the frame including the resource indication field; and may be located at the station when receiving the frame including the resource indicator field.

Fig. 11 is a block diagram of a transmitting station of another embodiment of the present invention. The transmission point of fig. 11 comprises an interface 101, a processing unit 102 and a memory 103. The processing unit 102 controls the operation of the transmitting station 100. Memory 103 may include both read-only memory and random access memory, and provides instructions and data to processing unit 102. A portion of the memory 103 may also include non-volatile row random access memory (NVRAM). The various components of the transmitting station 100 are coupled together by a bus system 109, wherein the bus system 109 comprises, in addition to a data bus, a power bus, a control bus and a status signal bus. For clarity of illustration, however, the various buses are labeled in the figure as bus system 109.

The method for transmitting the foregoing frames according to the embodiments of the present invention may be applied to the processing unit 102, or implemented by the processing unit 102. In implementation, the steps of the above method may be performed by integrated logic circuits of hardware or instructions in the form of software in the processing unit 102. The processing unit 102 may be a general purpose processor, a digital signal processor, an application specific integrated circuit, a field programmable gate array or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof, configured to implement or perform the methods, steps, and logic blocks disclosed in embodiments of the present invention. A general purpose processor may be a microprocessor or any conventional processor or the like. The steps of a method disclosed in connection with the embodiments of the present invention may be directly implemented by a hardware processor, or may be implemented by a combination of hardware and software modules in the processor. The software module may be located in ram, flash memory, rom, prom, or eprom, registers, etc. storage media as is well known in the art. The storage medium is located in the memory 103, and the processing unit 102 reads the information in the memory 103 and completes the steps of the above method in combination with the hardware thereof.

Fig. 12 is a block diagram of a receiving station of another embodiment of the present invention. The receiving station of fig. 12 comprises an interface 111, a processing unit 112 and a memory 113. The processing unit 112 controls the operation of the receiving station 110. Memory 113 may include both read-only memory and random access memory, and provides instructions and data to processing unit 112. A portion of the memory 113 may also include non-volatile row random access memory (NVRAM). The various components of the receiving station 110 are coupled together by a bus system 119, wherein the bus system 119 includes a power bus, a control bus, and a status signal bus in addition to a data bus. But for clarity of illustration the various buses are labeled in the figure as the bus system 119.

The method for receiving the foregoing frames according to the embodiments of the present invention may be applied to the processing unit 112, or implemented by the processing unit 112. In implementation, the steps of the above method may be performed by integrated logic circuits of hardware or instructions in the form of software in the processing unit 112. The processing unit 112 may be a general purpose processor, a digital signal processor, an application specific integrated circuit, a field programmable gate array or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or the like that implement or perform the methods, steps, and logic blocks disclosed in embodiments of the present invention. A general purpose processor may be a microprocessor or any conventional processor or the like. The steps of a method disclosed in connection with the embodiments of the present invention may be directly implemented by a hardware processor, or may be implemented by a combination of hardware and software modules in the processor. The software module may be located in ram, flash memory, rom, prom, or eprom, registers, etc. storage media as is well known in the art. The storage medium is located in the memory 113, and the processing unit 112 reads the information in the memory 113 and performs the steps of the above method in combination with the hardware thereof.

Specifically, memory 113 stores instructions that cause processing unit 112 to: determining resource state information which indicates the busy-idle state of sub-resources of channel resources for data transmission between the access point and the site; and sending the resource state information to the access point so that the access point can allocate the resources according to the resource state information.

It should be appreciated that reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In various embodiments of the present invention, the sequence numbers of the above-mentioned processes do not mean the execution sequence, and the execution sequence of each process should be determined by its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

Additionally, the terms "system" and "network" are often used interchangeably herein. The term "and/or" herein is merely an association describing an associated object, meaning that three relationships may exist, e.g., a and/or B, may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.

It should be understood that in the present embodiment, "B corresponding to a" means that B is associated with a, from which B can be determined. It should also be understood that determining B from a does not mean determining B from a alone, but may be determined from a and/or other information.

Those of ordinary skill in the art will appreciate that the elements and algorithm steps of the examples described in connection with the embodiments disclosed herein may be embodied in electronic hardware, computer software, or combinations of both, and that the components and steps of the examples have been described in a functional general in the foregoing description for the purpose of illustrating clearly the interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.

In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may also be an electric, mechanical or other form of connection.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment of the present invention.

In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.

From the above description of the embodiments, it is clear to those skilled in the art that the present invention can be implemented by hardware, firmware, or a combination thereof. When implemented in software, the functions described above may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage media may be any available media that can be accessed by a computer. Taking this as an example but not limiting: computer-readable media can include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. Furthermore, the method is simple. Any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, a server, or other remote sources using a coaxial cable, a fiber optic cable, a twisted pair, a Digital STA Line (DSL), or a wireless technology such as infrared, radio, and microwave, the coaxial cable, the fiber optic cable, the twisted pair, the DSL, or the wireless technology such as infrared, radio, and microwave are included in the fixation of the medium. Disk and disc, as used herein, includes Compact Disc (CD), laser disc, optical disc, Digital Versatile Disc (DVD), floppy Disk and blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

In short, the above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A data transmission method applied to a Wireless Local Area Network (WLAN), comprising:

transmitting a physical layer packet containing the L-SIG and the OFDM symbol;

the protocol version corresponding to the characteristic sequence is an 802.11ax protocol or a subsequent evolution protocol.

2. The method of claim 1, wherein the signal on the L-SIG data subcarrier is a Binary Phase Shift Keying (BPSK) modulation symbol.

3. The method of claim 1 or 2, wherein the number of data subcarriers of the L-SIG and the OFDM symbol is 48 or 52.

4. The method of claim 1 or 2, wherein the signature sequence is a sequence consisting of +1 and-1.

5. The method of claim 4, wherein the signature sequence has a length equal to a number of data subcarriers of the L-SIG.

6. A data transmission method applied to a Wireless Local Area Network (WLAN), comprising:

receiving a physical layer packet;

multiplying the signals on the data subcarriers of the first orthogonal frequency division multiplexing OFDM symbol after the traditional signaling field L-SIG in the physical layer packet one by one with each element of the characteristic sequence, and performing cross-correlation processing on the signals obtained after multiplication and the signals on the data subcarriers of the L-SIG;

determining a protocol version of the physical layer packet specifically includes: if the result of the cross-correlation processing exceeds a first threshold, determining that the physical layer packet is a physical layer packet of a protocol version corresponding to the characteristic sequence;

7. The method of claim 6, wherein the number of data subcarriers of the L-SIG and the first Orthogonal Frequency Division Multiplexing (OFDM) symbol after the L-SIG is 48 or 52.

8. The method of claim 6, wherein the signature sequence is a sequence consisting of +1 and-1.

9. The method of claim 6 or 8, wherein the length of the signature sequence is the same as the number of data subcarriers of the L-SIG.

10. A data transmission apparatus for a wireless local area network WLAN, comprising:

a transceiving unit configured to transmit a physical layer packet including the L-SIG and the OFDM symbol;

11. The apparatus of claim 10, wherein the signal on the L-SIG data subcarrier in the physical layer packet generated by the processing unit is a Binary Phase Shift Keying (BPSK) modulation symbol.

12. The apparatus according to claim 10 or 11, wherein the number of data subcarriers of the OFDM symbol and L-SIG in the physical layer packet generated by the processing unit is 48 or 52.

13. The apparatus of claim 10 or 11, wherein the signature sequence is a sequence consisting of +1 and-1.

14. The apparatus of claim 13, wherein the signature sequence has a length that is the same as a number of data subcarriers of the L-SIG.

15. A data transmission apparatus for a wireless local area network WLAN, comprising:

a transceiving unit for receiving a physical layer packet;

the processing unit is used for analyzing the physical layer packet and specifically comprises the steps of multiplying signals on data subcarriers of a first orthogonal frequency division multiplexing OFDM symbol after a traditional signaling field L-SIG in the physical layer packet by each element of a characteristic sequence one by one, and performing cross-correlation processing on the signals obtained after multiplication and the signals on the data subcarriers of the L-SIG;

a processing unit, configured to determine a protocol version of the physical layer packet, and specifically include: if the result of the cross-correlation processing exceeds a first threshold, determining that the physical layer packet is a physical layer packet of a protocol version corresponding to the characteristic sequence;

16. The apparatus of claim 15, wherein the number of data subcarriers of the L-SIG and the first OFDM symbol after the L-SIG in the parsed data packet by the processing unit is 48 or 52.

17. The apparatus of claim 15, wherein the signature sequence is a sequence consisting of +1 and-1.

18. The apparatus of claim 15 or 17, wherein the length of the signature sequence is the same as the number of data subcarriers of the L-SIG.