CN117640314A - Communication method and device - Google Patents

Disclosure of Invention

The application provides a communication method and a communication device, which are used for improving demodulation performance of a receiving end.

In a first aspect, the present application provides a communication method, which may be applied to a receiving end, a processor, a chip or a functional module in the receiving end. The method may include: after receiving a first reference signal sent by a sending end, a receiving end determines a frequency offset estimation value according to the first reference signal, and further receives a signal sent by the sending end on the first channel based on a frequency offset correction result after performing frequency offset correction according to the frequency offset estimation value. The first reference signal may be used for frequency offset estimation, the frequency domain range of the first reference signal is greater than the frequency domain range of the first channel, and the frequency domain range of the first reference signal includes the frequency domain range of the first channel.

By the method, the receiving end carries out frequency offset correction after carrying out frequency offset estimation based on the first reference signal so as to reduce or eliminate the frequency offset, so that when the first channel receives the signal sent by the sending end, interference signals of other channels are not received, and the demodulation performance of the receiving end is improved. Meanwhile, since the frequency domain range of the first reference signal is larger than that of the first channel, that is, the frequency domain range of the first reference signal is larger and the frequency domain range of the first channel is smaller, the resource overhead can be saved.

In one possible design, the first reference signal may be a signal whose frequency varies linearly with time. Therefore, the first reference signal can be sent, and the frequency offset estimation is realized.

In one possible design, the method may include the receiving end determining the frequency offset estimation value according to the first reference signal: the receiving end can carry out filtering processing on the first reference signal to obtain a filtered reference signal, and carry out envelope detection on the filtered reference signal to obtain a first envelope signal; and the receiving end determines the frequency offset estimation value according to the time difference between the amplitude peaks of the first envelope signal. Therefore, the receiving end can accurately determine the frequency offset estimated value based on the time difference between the amplitude peaks of the envelope signals obtained by the first reference signals, and can accurately correct the frequency offset of carrier frequency signals generated by the local crystal oscillator of the receiving end.

In one possible design, the receiving end determines the frequency offset estimation value according to a time difference between amplitude peaks of the first envelope signal, and the method may be: the receiving end may determine a first frequency according to a time difference between amplitude peaks of the first envelope signal, a transmission duration of the first reference signal, a lowest frequency of the first reference signal, and a slope of the first reference signal, and determine the frequency offset estimation value according to the first frequency and the second frequency. Wherein, the first frequency is the frequency with frequency deviation; the second frequency is a frequency without frequency offset. Based on the method, the receiving end can accurately determine the frequency offset estimation value according to the first frequency with the frequency offset and the second frequency without the frequency offset, and further can accurately correct the frequency offset of the carrier frequency signal generated by the local crystal oscillator of the receiving end.

In one possible design, the first frequency may conform to the following formula:

wherein T is _interval Is the time difference, f, between the amplitude peaks of the first envelope signal _low For frequency sweep signalThe lowest frequency of the numbers, alpha is the slope of the first reference signal, T is the transmission duration of the first reference signal, and f is the first frequency.

In one possible design, the first frequency may conform to the following formula:

wherein T is _interval Is the time difference, f, between the amplitude peaks of the first envelope signal _low For the lowest frequency of the sweep signal, α is the slope of the first reference signal, T is the transmission duration of the first reference signal, f is the first frequency, and Δ is the time domain interval between the frequency rising portion and the frequency falling portion of the sweep signal.

In one possible design, the first reference signal may be at least one ON-OFF keying (OOK) modulated sequence carried ON at least one sub-band, each of which may include at least one sub-carrier, and each of which may carry at least one OOK modulated sequence. The first reference signal can be sent through the OOK modulated sequence, and frequency offset estimation is further achieved.

In one possible design, the method may include the receiving end determining the frequency offset estimation value according to the first reference signal: the receiving end carries out filtering processing on the first reference signal to obtain a filtered reference signal, and carries out envelope detection on the filtered reference signal to obtain a second envelope signal; further, the receiving end demodulates the second envelope signal to obtain a demodulated signal, and determines a first sub-band corresponding to the demodulated signal; finally, the receiving end may determine the frequency offset estimation value according to the first sub-band and the second sub-band, where the second sub-band is a sub-band where no frequency offset exists, and the at least one sub-band includes the second sub-band. Based on the frequency offset estimation value can be accurately determined by the receiving end according to the deviation between the first sub-band and the second sub-band, and the frequency offset of the carrier frequency signal generated by the local crystal oscillator of the receiving end can be accurately corrected.

In one possible design, the receiving end may further receive a second reference signal sent by the sending end, where the second reference signal may be used for frequency offset estimation; the receiving end determines the frequency offset estimation value according to the first reference signal, and the method can be as follows: the receiving end determines the frequency offset estimation value according to the first reference signal and the second reference signal. Thus, the receiving end can accurately perform frequency offset estimation through the received two reference signals.

In one possible design, the receiving end determines the frequency offset estimation value according to the first reference signal and the second reference signal, and the method may be: after the receiving end determines the first time difference, the frequency offset estimation value is determined according to the first time difference and the second time difference. Wherein the first time difference is a time difference between the receiving end receiving the first reference signal and the receiving end receiving the second reference signal; the second time difference is a time difference between the sending end sending the first reference signal and the second reference signal. By the method, the receiving end can accurately determine the frequency offset estimated value through the deviation between the receiving time difference and the sending time difference between the two reference signals, and can accurately correct the frequency offset of the carrier frequency signal generated by the local crystal oscillator of the receiving end.

In one possible design, the receiving end may also receive the second time difference sent by the sending end. And the receiving end can combine the first time difference to perform frequency offset estimation.

In a second aspect, the present application provides a communication method, which may be applied to a transmitting end, a processor, a chip or a functional module in the transmitting end. The method may include: the transmitting end transmits a first reference signal to the receiving end and transmits a signal to the receiving end on the first channel. Wherein the first reference signal may be used for frequency offset estimation; the frequency domain range of the first reference signal is greater than the frequency domain range of the first channel, and the frequency domain range of the first reference signal includes the frequency domain range of the first channel.

By the method, the receiving end can perform frequency offset estimation based on the first reference signal so as to reduce or eliminate the frequency offset, so that when the first channel receives the signal sent by the sending end, interference signals of other channels are not received, and the demodulation performance of the receiving end is improved. Meanwhile, since the frequency domain range of the first reference signal is larger than that of the first channel, that is, the frequency domain range of the first reference signal is larger and the frequency domain range of the first channel is smaller, the resource overhead can be saved.

In one possible design, the first reference signal may be a signal whose frequency varies linearly with time. Therefore, the first reference signal can be sent, and the frequency offset estimation is realized.

In one possible design, the first reference signal may be at least one OOK modulated sequence carried on at least one subband, each of the at least one subband may include at least one subcarrier, and each of the at least one subband may carry at least one OOK modulated sequence. Therefore, the first reference signal can be sent through the OOK modulated sequence, and the frequency offset estimation is realized.

In one possible design, the transmitting end may send a second reference signal to the receiving end, where the second reference signal is used for frequency offset estimation. So that the receiving end can perform frequency offset estimation according to the first reference signal and the second reference signal.

In one possible design, the transmitting end may send a second time difference to the receiving end, where the second time difference is a time difference between the transmitting end sending the first reference signal and the second reference signal. So that the receiving end combines the time difference between the first reference signal and the second reference signal received by the receiving end to realize frequency offset estimation.

In a third aspect, the present application also provides a communication device, which may be a receiving end, having a function of implementing the method in the above-mentioned first aspect or each possible design example of the first aspect. The functions may be implemented by hardware, or may be implemented by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the functions described above.

In one possible design, the structure of the communication device includes a transceiver unit and a processing unit, where these units may perform corresponding functions in the foregoing first aspect or each possible design example of the first aspect, and detailed descriptions in method examples are specifically referred to herein and are not repeated herein.

In one possible design, the structure of the communication device includes a transceiver and a processor, and optionally further includes a memory, where the transceiver is configured to receive signals and to perform communication interaction with other devices in the communication system, and the processor is configured to support the communication device to perform the corresponding function in the foregoing first aspect or each possible design example of the first aspect. The memory is coupled to the processor that holds the program instructions and data necessary for the communication device.

Alternatively, the transceiver may include a receiver that may include a first intermediate frequency filter and a second intermediate frequency filter, the frequency domain range of the first intermediate frequency filter being smaller than the frequency domain range of the second intermediate frequency filter, wherein the first intermediate frequency filter may be used to filter a received reference signal (e.g., a first reference signal) and the second intermediate frequency filter may be used to filter a received signal of the first channel.

In a fourth aspect, the present application also provides a communication apparatus, which may be a transmitting end, having a function of implementing the method in the above-described second aspect or each possible design example of the second aspect. The functions may be implemented by hardware, or may be implemented by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the functions described above.

In one possible design, the structure of the communication device includes a transceiver unit and a processing unit, where these units may perform corresponding functions in the foregoing second aspect or each possible design example of the second aspect, and detailed descriptions in method examples are specifically referred to herein and are not repeated herein.

In one possible design, the structure of the communication apparatus includes a transceiver and a processor, and optionally further includes a memory, where the transceiver is configured to receive signals and to interact with other devices in the communication system, and the processor is configured to support the communication apparatus to perform the corresponding function in the second aspect or each possible design example of the second aspect. The memory is coupled to the processor that holds the program instructions and data necessary for the communication device.

In a fifth aspect, embodiments of the present application provide a communication system that may include the above-mentioned receiving end, transmitting end, and the like.

In a sixth aspect, embodiments of the present application provide a computer readable storage medium storing program instructions that, when run on a computer, cause the computer to perform the method described in the first aspect of the embodiments of the present application and any one of the possible designs thereof, or in the second aspect and any one of the possible designs thereof. By way of example, computer-readable storage media can be any available media that can be accessed by a computer. Taking this as an example but not limited to: the computer readable medium may include non-transitory computer readable media, random-access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (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.

In a seventh aspect, embodiments of the present application provide a computer program product comprising computer program code or instructions which, when run on a computer, cause the method described in the first aspect or any one of the possible designs of the second aspect or the second aspect to be performed.

In an eighth aspect, the present application further provides a chip comprising a processor coupled to a memory for reading and executing program instructions stored in the memory, to cause the chip to implement the method described in the first aspect or any one of the possible designs of the first aspect or the second aspect or any one of the possible designs of the second aspect.

The technical effects of each of the third to eighth aspects and the technical effects that may be achieved by each of the aspects are referred to the above description of each of the possible aspects of the first aspect or the first aspect, or the technical effects that may be achieved by each of the possible aspects of the second aspect or the second aspect, and the detailed description is not repeated here.

Detailed Description

The present application will be described in further detail with reference to the accompanying drawings.

The embodiment of the application provides a communication method and a communication device, which are used for improving the demodulation performance of a receiving end. The method and the device described in the present application are based on the same technical concept, and because the principles of solving the problems by the method and the device are similar, the implementation of the device and the method can be referred to each other, and the repetition is not repeated.

In the description of this application, the words "first," "second," and the like are used solely for the purpose of distinguishing between descriptions and not necessarily for the purpose of indicating or implying a relative importance or order.

In the description herein, "at least one species" means one species or a plurality of species, and a plurality of species means two species or more than two species. "at least one of the following" or similar expressions thereof, means any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c may represent: a, b, c, a and b, a and c, b and c, or a and b and c, wherein a, b, c may be single or plural.

In the description of the present application, "and/or", describing the association relationship of the association object, it means that there may be three relationships, for example, a and/or B may mean: a alone, a and B together, and B alone, wherein A, B may be singular or plural. "/" means "OR", e.g., a/b means a or b.

The communication method provided by the embodiment of the application can be applied to various communication systems. For example, the communication method of the embodiment of the present application may be applied to a third generation (3th generation,3G) communication system, a fourth generation (4th generation,4G) communication system, a fifth generation (5th generation,5G) communication system, a sixth generation (6th generation,6G) communication system in the future, or other systems. The communication method of the embodiment of the application can also be applied to short-distance wireless communication systems such as side links (sidelink), wireless fidelity (wireless fidelity, wifi), bluetooth and the like.

Fig. 1a and 1b illustrate exemplary architectures of possible communication systems to which the communication method provided in the present application is applicable.

The architecture of the communication system shown in fig. 1a may comprise network devices and terminal devices. The network device may send a downlink signal to the terminal device, and the network device and the terminal device may support an envelope detection modulation technique.

The architecture of the communication system shown in fig. 1b may comprise at least two terminal devices, e.g. terminal device 1 and terminal device 2 in fig. 1b, which mutually transmit signals, e.g. two terminal devices can mutually transmit signals via a side-link. At least two terminal devices may each support an envelope detection modulation technique.

The network device may be a device providing access to the terminal device. The network device may be a radio access network (radio access network, RAN) device, such as a base station. The network device may also refer to a device that communicates with the terminal device over the air. The network device may include an evolved Node B, an eNB, or an e-NodeB in a long term evolution (long term evolution, LTE) system or an LTE-advanced (long term evolution-advanced, LTE-a) system. The network device may also be a new radio controller (new radio controller, NR controller), may be a base station (gnnode B, gNB) in a 5G system, may be a centralized network element (centralized unit), may be a new radio base station, may be a remote radio module, may be a micro base station (also referred to as a small station), may be a relay (relay), may be a distributed network element (distributed unit), may be a macro base station in various forms, may be a transmission receiving point (transmission reception point, TRP), a transmission measurement function (transmission measurement function, TMF) or a transmission point (transmission point, TP), or any other wireless access device, and embodiments of the present application are not limited thereto. The network device may also include at least one of: a radio network controller (radio network controller, RNC), a Node B (NB), a base station controller (base station controller, BSC), a base transceiver station (base transceiver station, BTS), a home base station (e.g., home evolved NodeB, or home Node B, HNB), a Base Band Unit (BBU), a radio remote unit (remote radio unit, RRU), a wifi Access Point (AP), or a baseband pool (BBU pool) in a cloud radio access network (cloud radio access netowrk, CRAN), etc. The embodiments of the present application do not limit the specific technology and specific device configuration used by the network device. For example, the network device may correspond to an eNB in a 4G system and to a gNB in a 5G system.

In this application, the network device may also be a functional module, a chip, or a chip system. Alternatively, the functional module, chip or chip system may be provided within the network device.

The terminal device may also be referred to as a User Equipment (UE), a Mobile Station (MS), a Mobile Terminal (MT), etc., and is a device that provides voice and/or data connectivity to a user. For example, the terminal device may include a handheld device, an in-vehicle device, or the like having a wireless connection function. Currently, the terminal device may be: a mobile phone, a tablet, a notebook, a palm, a mobile internet device (mobile internet device, MID), a wearable device, a Virtual Reality (VR) device, an augmented reality (augmented reality, AR) device, an XR device, an MR device, a wireless terminal in industrial control (industrial control), a wireless terminal in unmanned (self-driving), a wireless terminal in teleoperation (remote medical surgery), a wireless terminal in smart grid (smart grid), a wireless terminal in transportation security (transportation safety), a wireless terminal in smart city, or a wireless terminal in smart home (smart home), and the like.

The terminal device may also be a device-to-device (D2D) terminal device, a vehicle networking V2X communication terminal device, an intelligent vehicle, a vehicle-to-machine system (TBOX), a machine-to-machine/machine-type communication (M2M/MTC) terminal device, an internet of things (internet of things, ioT) terminal device. For example, the terminal device may be a vehicle, a ship, or an aircraft, or a terminal roadside unit, or a communication module or chip built in the vehicle or the roadside unit. For example, the terminal device may be a vehicle-mounted module. The terminal device may also be a Road Side Unit (RSU). While the various terminal devices described above, if located on a vehicle, such as placed in a vehicle or installed in a vehicle, may be considered as in-vehicle terminal devices, such as also known as in-vehicle units (OBUs).

By way of example, and not limitation, in embodiments of the present application, the terminal device may also be a wearable device. The wearable device can also be called as a wearable intelligent device or an intelligent wearable device, and is a generic name for intelligently designing daily wear and developing wearable devices, such as glasses, gloves, watches, clothes, shoes, and the like, by applying wearable technology. The wearable device is a portable device that is worn directly on the body or integrated into the clothing or accessories of the user. The wearable device is not only a hardware device, but also can realize a powerful function through software support, data interaction and cloud interaction. The generalized wearable intelligent device includes full functionality, large size, and may not rely on the smart phone to implement complete or partial functionality, such as: smart watches or smart glasses, etc., and focus on only certain types of application functions, and need to be used in combination with other devices, such as smart phones, for example, various smart bracelets, smart helmets, smart jewelry, etc. for physical sign monitoring.

The terminal equipment can also be intelligent equipment such as recreation equipment and intelligent electrical equipment or unmanned aerial vehicle.

In the present application, the terminal device may be, for example, the terminal device itself, or a module for realizing the functions of the terminal device, such as a chip or a chip system, which may be provided in the terminal device.

For ease of understanding, some technical terms related to the embodiments of the present application are explained below:

1) Envelope detection receiver

In some modulation schemes in communication systems, some signals may be received by an envelope detection receiver, such as amplitude modulation (amplitude modulation, AM) broadcast, or the like.

The general wireless communication system needs to use carrier frequency, and the carrier frequency of the transmission signal is assumed to be f _c The carrier signal can be expressed as cos (2pi.f _c t+φ ₀ )，φ ₀ Is the initial phase of the carrier frequency. If the signal to be transmitted is modulated in amplitude, it is assumed that the signal to be transmitted is s _AM (t), then the actually transmitted signal can be denoted as s _AM (t)·cos(2πf _c t+φ ₀ ) The waveform of the modulated signal may be a modulated waveform as shown in fig. 2.

At the receiving end, the modulated signal, i.e. s, needs to be demodulated _AM (t) this can be achieved by envelope detection. Envelope detection is to extract the envelope of the waveform of the Radio Frequency (RF) signal, such as the RF signal in FIG. 2, by using a detection circuit The envelope is shown by the outline curve, from which it can be seen that the envelope is the modulated signal s _AM (t)。

The envelope detection has the advantages of simplicity and low power consumption, and can be used on some communication equipment with requirements on cost or power consumption, such as Internet of things equipment.

Modulation techniques that may use envelope detection may include the following modulation schemes: amplitude Modulation (AM), ON-OFF-keying (ON-OFF-keying), amplitude keying (amplitude shift keying, ASK), etc.

2) OOK modulation

OOK modulation is a simple modulation scheme. This modulation scheme uses whether or not to transmit a signal to convey information.

OOK modulation, first generates a baseband waveform using a switch non-return-to-zero line code (ON-OFF NRZ line code) according to information to be modulated. The ON-OFF NRZ line code uses a high level to represent information bit (bit) "1", and uses a zero level to represent information bit "0", as shown in fig. 3, for example. The signal generated based on the above operations may be represented as s _nrz (t)。

Then, using carrier signal and s _nrz (t) multiplying to generate an OOK signal. Assuming that the carrier frequency of the transmitted signal is f _c The carrier signal can be expressed as cos (2pi.f _c t+φ ₀ )，φ ₀ Is the initial phase of the carrier frequency. The OOK signal generated may conform to the formula: s is(s) _OOK (t)＝s _nrz (t)cos(2πf _c t+φ ₀ ) The waveforms can be seen from the lower waveforms in fig. 3. It is understood that OOK modulation transmits a signal when information to be transmitted is '1', and does not transmit a signal when information to be transmitted is '0'.

At the receiving end, the receiver only needs to judge whether one symbol has energy or not to judge whether the transmitted signal is '0' or '1', thereby completing demodulation.

3) OOK envelope detection receiver

OOK modulation may also be demodulated with an envelope detector.

In FIG. 4, a conventional OOK connection is shownAnd the structure of the receiver. Here, it is assumed that the OOK signal is at the radio frequency (f _RF =3.5 GHz). At the receiving end, the radio frequency is first filtered by a radio frequency band pass filter (Radio frequency bandpass filter, RF BPF), the out-of-band signal is suppressed, and then the filtered signal is amplified using a radio frequency amplifier, such as a radio frequency low noise amplifier (RF low noise amplifier, RF LNA). Thereafter, a local carrier signal is generated by a Local Oscillator (LO), mixed with the amplified radio frequency signal, and the frequency of the signal is shifted to an intermediate frequency (intermediate frequency, IF). In this example, as shown in FIG. 4, assume that the intermediate frequency is f _IF =50 MHz. After amplifying and bandpass filtering the signal at the intermediate frequency, an OOK signal at the intermediate frequency can be obtained. Finally, after envelope detection by an envelope detector (envelope detector), an envelope waveform of the signal can be obtained, and OOK demodulation can be performed by the amplitude of the envelope waveform.

Shown in fig. 4 is a receiver architecture for down-converting a radio frequency signal to an intermediate frequency. The reason why the rf needs to be down-converted to the if frequency is that the receiving end needs to filter the target signal, filter the signals of other channels, and receive the signal of the target channel. The filter is difficult to realize in the radio frequency band, and is easy to realize in the intermediate frequency band. Receiver architectures in which intermediate frequencies exist are commonly employed in wireless communication systems.

The envelope signal of the OOK signal is a modulated ON-OFF NRZ baseband waveform, and demodulation of the OOK signal can be performed by the envelope signal.

4) Orthogonal frequency division multiplexing (orthogonal frequency division multiplexing, OFDM)

OFDM modulation is another widely used modulation technique, which is generally applied in a mobile broadband system, and provides a high transmission rate using a high communication bandwidth.

In OFDM modulation, the system bandwidth may be divided into multiple parallel subcarriers, and data is modulated on each subcarrier, each subcarrier having a different frequency, for transmission. In the transmitting and receiving processes of OFDM, firstly, the data to be transmitted is modulated and mapped into one Plural symbols, which may be written asa is the amplitude of the symbol, < >>For the phase of the symbols, the modulation may optionally be a quadrature amplitude modulation (quadrature amplitude modulation, QAM) mapping to map the information into one QAM symbol (QAM symbol is also a complex symbol). Then, each QAM symbol is mapped to a different subcarrier by serial-to-parallel conversion. Symbols on different subcarriers are input into an inverse fast fourier transform (inverse fast fourier transform, IFFT), and are subjected to an inverse fast fourier operation to be converted into a time-domain sequence.

In conventional OFDM symbol processing, the tail portion of the time domain sequence is copied to the front end of the signal, referred to as the Cyclic Prefix (CP). The main function of the cyclic prefix is to combat multipath propagation delays in the wireless channel. After the cyclic prefix addition is completed, the transmitter may digital-to-analog convert the signal (digital to analog conversion) and up-convert it for transmission.

5) Transmitting OOK signals using an OFDM system

In current cellular mobile communication networks, OFDM modulation techniques are typically used. The main purpose of cellular mobile communication networks is to provide mobile broadband services (mobile broad band, MBB), such as high-speed internet surfing, video browsing, file downloading, etc. using terminal equipment such as cell phones, tablets, etc.

However, in recent years, services provided by cellular mobile communication networks have tended to be diversified, and many terminal devices, such as internet of things devices, wearable devices (smart watches), low-power wake-up links (low power wake up radio), and the like, require low communication rates, but have high requirements for low cost and low power consumption of receivers. OFDM is not a suitable modulation scheme for these terminal devices because OFDM receivers require accurate time-frequency synchronization and complex signal processing, requiring high cost and power consumption. The industry considers that using a simpler modulation scheme to serve these devices, e.g., OOK is a better choice.

In order to achieve the purpose of serving different types of terminal equipment, one way is to set two sets of transmitters on a base station of a mobile communication network, one set of transmitters is used for sending OFDM signals to serve mobile broadband users, and the other set of transmitters is used for sending OOK signals to serve low-rate users. But this requires hardware upgrades to existing network equipment, i.e. adding a set of OOK transmitters on the basis of existing OFDM transmitters. This can be costly for the deployer of the network.

Alternatively, the transmitter may still use an existing OFDM transmitter architecture, but may generate other modulated waveforms at certain frequency bands by some means of signal processing. For example, an OFDM transmitter may generate OOK modulated waveforms over certain frequency bands.

For example, as shown in fig. 5, where 37 OFDM symbols are transmitted, each OFDM symbol shows 22 subcarriers, and assuming that the diagonally filled subcarriers are used to serve mobile broadband traffic and the middle 5 subcarriers (subcarriers 8-12) are used to serve low-speed traffic, the time domain waveform of the OFDM symbol is actually an OOK signal after the 5 subcarriers are filtered out by a filter when the symbol of "ON" needs to be transmitted, 5 subcarriers modulate the signal to be transmitted, such as the black OFDM symbol in fig. 5, and when the symbol of "OFF" needs to be transmitted, no data is modulated, such as the white OFDM symbol in fig. 5. In this way, only a software upgrade is required for the transmitter, and waveforms of other modulation techniques can be generated by the OFDM transmitter.

6) Frequency offset problem with intermediate frequency receiver

In the receiver architecture shown in fig. 4 described above, a local crystal oscillator is required to down-convert the rf signal to an intermediate frequency. However, some terminal devices, in consideration of cost or power consumption, use local oscillators with poor stability. At this time, the carrier signal generated by the crystal oscillator may deviate from the ideal frequency, and sometimes the frequency deviation is larger. Thus, the waveform of the target channel (i.e., the channel requiring the received signal) cannot be accurately converted to the passband of the filter, resulting in loss of signal energy, and thus the signal transmitted in the adjacent band may be converted to the passband of the filter, resulting in interference, thereby affecting demodulation performance.

For example, as shown in fig. 6, the black part shown in fig. 6 is the spectrum of a signal to be received (which may be understood as a signal of a target channel, which may also be referred to as a target signal), and the white part is a signal transmitted on an adjacent channel. In fig. 6 (a), when the frequency offset generated by the local crystal oscillator is small, after down-conversion, the spectrum of the target channel will be accurately migrated to the set intermediate frequency, the spectrum of the signal accurately falls into the bandwidth range of the intermediate frequency filter, after filtering, the signal of the target channel will be reserved, and the signal on the adjacent channel will be filtered.

However, if the local crystal oscillator generates a larger frequency offset, the frequency deviation will be generated after the down-conversion. As shown in fig. 6 (b), in the case of a large frequency offset, the frequency spectrum of the target channel cannot be accurately shifted to the intermediate frequency, and the filter will filter out part of the target signal, and in addition, part of the signal on the adjacent channel will pass through the filter and enter the subsequent processing of the receiver, so as to cause interference.

One current solution to the frequency offset problem is to increase the bandwidth of the transmitted signal (which may also be understood as the bandwidth of the target channel) beyond the bandwidth of the intermediate frequency filter. Therefore, even if a scene of larger frequency offset exists, the frequency spectrum of the adjacent band signal still does not enter the passband range of the filter, and the adjacent band interference is not caused. For example, as shown in fig. 7, the bandwidth of the target channel may be set larger, and the filter bandwidth of the receiver may be smaller than the bandwidth of the target channel. In this way, even in the presence of a frequency offset, the signal still being the target channel is received within the bandwidth of the filter, without receiving an interfering signal on the adjacent band. However, the above method can solve the interference problem caused by frequency offset, but causes waste of spectrum resources and the like.

Based on the above, the embodiment of the application provides a communication method to solve the frequency offset problem of the receiving end, reduce interference and improve demodulation performance.

In the following embodiments, the communication method provided in the embodiments of the present application will be described in detail by taking a transmitting end and a receiving end as examples, and it should be understood that the operations performed by the transmitting end may also be implemented by a processor in the transmitting end, or a chip system, or a functional module, etc., and the operations performed by the receiving end may also be implemented by a processor in the receiving end, or a chip system, or a functional module, etc., which are not limited in this application.

Alternatively, the transmitting end may be a network device, and the receiving end may be a terminal device. Alternatively, the transmitting end may be a terminal device, and the receiving end may be a terminal device, which is not limited in this application.

Based on the above description, the embodiment of the application provides a communication method, as shown in fig. 8, a flow of the method may include:

801: the transmitting end transmits a first reference signal to the receiving end.

Wherein the first reference signal may be used for frequency offset estimation; the frequency domain range of the first reference signal is greater than the frequency domain range of the first channel, and the frequency domain range of the first reference signal includes the frequency domain range of the first channel.

Correspondingly, the receiving end receives the first reference signal sent by the sending end.

The frequency domain range may also be described as a bandwidth, which is not limited in this application.

802: and the receiving end determines a frequency offset estimation value according to the first reference signal.

803: and the receiving end corrects the frequency offset according to the frequency offset estimation value.

For example, the performing, by the receiving end, frequency offset correction according to the frequency offset estimation value may specifically be: the receiving end compensates the frequency of a carrier signal generated by a local crystal oscillator of the receiver based on the frequency offset estimation value; or the receiving end adjusts the frequency multiplication coefficient of the frequency multiplication circuit of the receiver based on the frequency offset estimation value; or the receiving end generates a frequency offset compensation signal according to the frequency offset estimation value.

804: and the receiving end receives the signal sent by the sending end on the first channel based on the result of frequency offset correction.

Correspondingly, the transmitting end transmits signals to the receiving end in the first channel.

Optionally, under the condition that the receiving end compensates the frequency of the carrier signal generated by the local crystal oscillator based on the frequency offset estimation value or adjusts the frequency multiplication coefficient of the frequency multiplication circuit of the receiver, the frequency offset correction result is that the frequency offset of the receiving end is corrected, so that the receiving end can receive the signal sent by the sending end on the first channel under the condition of no frequency offset or smaller frequency offset.

Optionally, when the receiving end receives the signal sent by the sending end on the first channel based on the result of frequency offset correction under the condition that the receiving end generates the frequency offset compensation signal based on the frequency offset estimation value, the receiving end may multiply the received signal with the frequency offset compensation signal to obtain a signal without frequency offset or with smaller frequency offset (may be referred to as a correction signal). Wherein the multiplication of the received signal and the frequency offset compensation signal may be implemented by a multiplication circuit.

By the method, the receiving end carries out frequency offset correction after carrying out frequency offset estimation based on the first reference signal so as to reduce or eliminate the frequency offset, so that when the first channel receives the signal sent by the sending end, interference signals of other channels are not received, and the demodulation performance of the receiving end is improved. Meanwhile, since the frequency domain range of the first reference signal is larger than that of the first channel, that is, the frequency domain range of the first reference signal is larger and the frequency domain range of the first channel is smaller, the resource overhead can be saved.

Specifically, the frequency deviation (referred to as frequency offset) of the crystal oscillator in the receiver is mainly affected by the frequency drift. The frequency drift refers to that the frequency generated by the crystal oscillator deviates from the designed frequency in a period of time due to environmental influences such as temperature. This amount of deviation is itself relatively stable over a period of time, e.g., a few seconds, with less variation in the magnitude of the frequency deviation. Based on the method, the receiving end estimates the frequency offset and compensates the frequency of the carrier signal generated by the crystal oscillator, so that the frequency offset can be corrected to be smaller, and the signal interference of the adjacent band is reduced. After one frequency offset correction, the frequency offset can be kept small for a period of time, and the frequency offset of the receiver is kept low by frequency offset estimation and frequency offset correction because the size of the frequency drift is stable for a period of time. Alternatively, the receiving end may periodically perform frequency offset estimation and frequency offset correction to maintain the frequency offset of the receiver at a low level.

In an alternative embodiment, the first reference signal may be sent periodically or aperiodically. For example, fig. 9 shows a schematic diagram of periodic transmission of the first reference signal. For example, as shown in fig. 9, the frequency domain range of the first reference signal is W1, the frequency domain range of the first channel is W2, it can be seen that W1 is greater than W2, and W1 includes W2. The frequency domain range of the first reference signal used for frequency offset estimation is larger, and larger frequency offset can be accommodated, so that frequency offset estimation can be accurately realized.

Illustratively, the frequency domain range of the first channel may be greater than or equal to the frequency domain range of the intermediate frequency filter of the receiver, which may save resource overhead. For example, wf is exemplarily shown in fig. 9 as a frequency domain range of the receiver intermediate frequency filter, and Wf is exemplarily shown in fig. 9 as being smaller than W2.

In connection with the example shown in fig. 9, at time t1, there is a large frequency offset of the receiver, and as shown in fig. 9, the frequency domain range Wf of the intermediate frequency filter of the receiver is located above the frequency domain range W1 of the first reference signal, but because the frequency domain range of the first reference signal is large, the receiving end still does not receive the interference signal of the adjacent band even if there is a large frequency offset. After the receiving end carries out frequency offset estimation according to the first reference signal, the frequency of the carrier signal generated by the local crystal oscillator can be adjusted, so that the frequency offset of the receiver can be corrected, as shown by time t2 in fig. 9, and after the frequency offset correction, the frequency domain range Wf of the intermediate frequency filter of the receiver is basically matched with the frequency domain range of the first channel. Although the frequency domain range of the first channel is W2 and is reduced relative to the frequency domain range W1 of the first reference signal, the frequency offset of the receiver is corrected, so that the problem of adjacent band interference is not generated. After the correction of the frequency offset is completed, the receiver may keep the frequency offset smaller for a period of time, for example, at the time of t3 and t4, and the receiving end basically stays within the frequency domain of the first channel although some frequency drift occurs. The frequency offset is larger at time t5, but the time of the first reference signal transmission is also entered, so the frequency offset can be compensated (time t 6) after the previous steps are repeated and the frequency offset estimation and correction are performed, and the signal can be transmitted by using a narrower frequency domain range W2.

According to the method, the receiving end carries out frequency offset correction after carrying out frequency offset estimation based on the first reference signal, so that the frequency offset can be reduced or eliminated, interference signals of other channels are not received when the first channel receives signals sent by the sending end, and the demodulation performance of the receiving end is improved. Meanwhile, compared with the situation that the frequency domain ranges of the first reference signal and the first channel are large, the resource expense can be saved.

Alternatively, the first reference signal may be implemented in two ways:

the mode a1, the first reference signal may be a signal whose signal frequency varies linearly with time.

For example, the signal whose frequency varies linearly with time may include a swept frequency signal or the like. In the following description, in the mode a1, the first reference signal is illustrated with a sweep signal, and it should be understood that this is not a limitation of the present application.

In one example, the swept signal may be a low to high to low frequency signal or the swept signal may be a high to low to high signal. For example, fig. 10 shows a schematic diagram of the first reference signal being a frequency sweep signal, where the frequency of the frequency sweep signal in fig. 10 ranges from low to high to low, and the frequency domain of the frequency sweep signal ranges from W1. Alternatively, the time domain waveform of the sweep signal shown in fig. 10 may be as shown in fig. 11, and it can be seen from fig. 11 that the frequency domain of the sweep signal is from low to high and then from high to low.

Alternatively, the swept frequency signal may conform to the following equation one:

wherein s is _fmcw,n+1 (t) is the sweep frequency signal at time t, f _low The method is characterized in that alpha is the slope of the frequency sweep signal, T is the duration of the frequency sweep signal, n is the waveform sequence of the frequency sweep signal, rising period of the frequency sweep signal is the rising period of the frequency sweep signal, and falling period of the frequency sweep signal is the falling period of the frequency sweep signal.

For another example, fig. 12 shows another schematic diagram in which the first reference signal is a frequency sweep signal, in fig. 12, the frequency of the frequency sweep signal ranges from low to high to low, and the frequency domain of the frequency sweep signal ranges from W1, which is different from the frequency sweep signal in fig. 10 in that there is a time domain interval Δ between the frequency rising portion and the frequency falling portion of the frequency sweep signal in fig. 12.

In the mode a1, the receiving end determines the frequency offset estimation value according to the first reference signal, and the method may be: the receiving end carries out filtering processing on the first reference signal to obtain a filtered reference signal; the receiving end carries out envelope detection on the filtered reference signal to obtain a first envelope signal; and the receiving end determines a frequency offset estimation value according to the time difference between amplitude peaks of the first envelope signal.

For example, in the case where the sweep signal is transmitted as the first reference signal, when the receiving end filters the sweep signal, the frequency of the sweep signal may intersect the filtering frequency of the filter of the receiving end at two times, as shown in the left-hand diagrams of fig. 13 and 14. During the crossing time, more energy passes through the filter, and at other times, the output energy of the filter is lower because no swept signal passes through the filter.

A schematic diagram of the intersection of the swept frequency and the filtered frequency for both cases where frequency offset 1 is present and where frequency offset 2 is present is shown in fig. 13. A schematic diagram of the intersection of the swept frequency and the filtered frequency in the presence of frequency offset 1 is shown in fig. 14. It can also be seen from fig. 13 that, with different frequency offsets, the intersecting time intervals are different, and there is a correspondence between the intervals between the intersecting times and the magnitudes of the frequency offsets. For example, in the case that the frequency after the frequency offset is large relative to the frequency without the frequency offset, the larger the intersecting time interval is, the larger the frequency offset is; under the condition that the frequency after the frequency offset is smaller than the frequency without the frequency offset, the larger the intersecting time interval is, the smaller the frequency offset is.

Further, after the receiving end obtains the first envelope signal, the first envelope signal has two amplitude peaks (i.e. two peaks), for example, as shown in the right-hand diagrams in fig. 13 and 14. Furthermore, the receiving end can detect the time difference between the amplitude peaks of the first envelope signal, and the frequency offset estimation value can be determined through the time difference.

Optionally, the receiving end determines the frequency offset estimation value according to the time difference between amplitude peaks of the first envelope signal, and the method may be: the receiving end can determine a first frequency according to the time difference between amplitude peaks of the first envelope signal, the sending duration of the first reference signal, the lowest frequency of the first reference signal and the slope of the first reference signal, wherein the first frequency is the frequency with frequency deviation; then, the receiving end determines a frequency offset estimation value according to the first frequency and the second frequency, wherein the second frequency is the frequency without frequency offset. The difference between the first frequency and the second frequency is an estimated frequency offset value.

In one example, the first frequency may satisfy the following equation two:

wherein T is _interval Is the time difference, f, between the amplitude peaks of the first envelope signal _low For the lowest frequency of the sweep frequency signal, alpha is the slope of the first reference signal, T is the transmission duration of the first reference signal, and f is the first frequency.

In another example, the first frequency may also satisfy the following equation three:

wherein T is _interval Is the time difference, f, between the amplitude peaks of the first envelope signal _low For the lowest frequency of the sweep signal, α is the slope of the first reference signal, T is the transmission duration of the first reference signal, f is the first frequency, and Δ is the time domain interval between the frequency rising portion and the frequency falling portion of the sweep signal.

Alternatively, the second frequency may be predefined. Alternatively, the transmitting end broadcasts the second frequency, and the receiving end may receive the second frequency.

The mode a2, the first reference signal may be at least one OOK modulated sequence carried on at least one subband, each of the at least one subband including at least one subcarrier, each of the at least one subband carrying at least one OOK modulated sequence.

In this mode a2, the first reference signal may be a signal transmitted by the transmitting end based on the OFDM transmitter. For example, the transmitting end may carry different OOK modulated sequences on different subbands by the OFDM transmitter.

Optionally, the receiving end determines the frequency offset estimation value according to the first reference signal, and the method may be: firstly, a receiving end carries out filtering processing on a first reference signal to obtain a filtered reference signal; the receiving end carries out envelope detection on the filtered reference signal to obtain a second envelope signal; then, the receiving end demodulates the second envelope signal to obtain a demodulated signal, and determines a first sub-band corresponding to the demodulated signal; the receiving end determines a frequency offset estimation value according to a first sub-band and a second sub-band, wherein the second sub-band is a sub-band without frequency offset, and the at least one sub-band comprises the second sub-band. The demodulated signal is the OOK modulated sequence carried on the first subband.

Optionally, the frequency difference between the first sub-band and the second sub-band is a frequency offset estimation value.

In this way, as different sub-bands modulate different sequences, when the receiving end is in different frequency offsets, different OOK modulated sequences can be demodulated, and the size of the frequency offset can be judged.

For example, as shown in fig. 15, it is assumed that OFDM symbols 0 to 3 are used for transmitting the first reference signal, and OFDM symbols 4 to 36 are used for transmitting the signal of the first channel. The frequency domain range of 15 subcarriers (subcarriers 3 to 17) is occupied at the time of the first reference signal transmission, and the frequency domain range of 5 subcarriers (subcarriers 8 to 12) is occupied at the time of the signal transmission of the first channel.

ON the time-frequency resources where the first reference signal is transmitted, each sub-band carries a different OOK modulated sequence, for example sub-carrier 3, the modulated sequence being "OFF ON", or written as "0001" in the form of a bit string, and sub-carrier 4, the modulated sequence being "0010", the other sub-carriers being similar.

When the receiver has no frequency offset, the filter may operate at an intermediate frequency point, for example, subcarrier 10 (i.e., the second subband) in fig. 15, where the bit sequence obtained after envelope detection and demodulation by the receiving end is "1000". Optionally, when there is no frequency offset, the sequence obtained by demodulation at the receiving end is predefined. If there is a frequency offset, the filter will filter out the signals of other subcarriers, and it is assumed that the sequence obtained after demodulation at the receiving end is "1011", so that it can be determined that the currently demodulated subband corresponds to subcarrier 13 (i.e., the first subband). Therefore, the receiving end can judge that the frequency deviation of 3 subcarriers exists currently, namely the receiving end can determine the frequency deviation estimated value.

In this manner a2, in a possible example, when the transmitting end transmits the first reference signal, a signal similar to the frequency sweep signal may be generated based on the OFDM transmitter, for example, the schematic diagram of the first reference signal shown in fig. 16. The first reference signal shown in fig. 16 occupies a length of 15 OFDM symbols, where OFDM symbol 0 modulates a sequence on subcarrier 0, OFDM symbol 1 modulates a sequence on subcarrier 1, and so on until OFDM symbol 7 modulates a sequence on subcarrier 7, further between OFDM symbol 7 and OFDM symbol 14, the subcarrier numbers of the modulated sequences decrease one by one. By the above method, as shown in fig. 17, compared to the sweep signal in the above mode a1, the instantaneous frequency of the first reference signal in the mode a2 is demodulated, rather than ramped.

Similarly, after the receiving end performs the filtering process and the envelope detection process on the first reference signal, two amplitude peaks still exist in the obtained envelope signal, for example, as shown in fig. 18. Furthermore, the receiving end can determine the frequency offset estimation value according to the distance between the two amplitude peaks. The method of determining the frequency offset estimation value by the receiving end according to the distance between two amplitude peaks is similar to the method of determining the frequency offset estimation value by the receiving end according to the time difference between the amplitude peaks of the first envelope signal in the above-mentioned mode a1, which will not be described in detail herein.

The foregoing describes two implementations of the first reference signal and a method for implementing frequency offset estimation based on the corresponding first reference signal. Alternatively, the transmitting end may transmit a plurality of reference signals for frequency offset estimation to the receiving end, and perform frequency offset estimation based on a time difference between the plurality of reference signals. The following is an expanded introduction:

for example, the reference signal sent by the sending end may use a sequence with good autocorrelation characteristics, such as an M sequence or a Gold sequence. The reference signal may be OOK modulated or ASK modulated. The frequency domain range of the plurality of reference signals is larger than the frequency domain range of the first channel, and comprises the frequency domain range of the first channel.

Taking the sending end to send two reference signals as an example, besides the first reference signal, the sending end can also send a second reference signal to the receiving end, and correspondingly, the receiving end can also receive the second reference signal sent by the sending end, wherein the second reference signal is used for frequency offset estimation.

Accordingly, the receiving end can determine the frequency offset estimation value according to the first reference signal and the second reference signal.

Optionally, the receiving end determines the frequency offset estimation value according to the first reference signal and the second reference signal, and the method may be: the receiving end determines a first time difference, wherein the first time difference is the time difference between the receiving end receiving the first reference signal and the receiving end receiving the second reference signal; the receiving end determines a frequency offset estimation value according to the first time difference and the second time difference, wherein the second time difference is the time difference between the sending end sending the first reference signal and the second reference signal.

For example, when the transmitting end transmits at least two reference signals, the receiving end may be informed of a time difference between transmitting the at least two reference signals. For example, in the case that the transmitting end transmits the first reference signal and the second reference signal to the receiving end, the transmitting end may also transmit the second time difference to the receiving end.

Optionally, the transmitting end may send the sequence of at least two reference signals to the receiving end, so that the receiving end may store the sequence locally, so as to facilitate operations such as correlation with the received reference signals.

After receiving the first reference signal, the receiving end performs down-conversion processing on the received first reference signal, performs filtering processing on the received first reference signal, performs envelope detection on the filtered signal, and performs correlation processing on the envelope signal obtained by the envelope detection and a corresponding sequence stored locally, so that the time for receiving the first reference signal can be obtained. Similarly, after the receiving end receives the second reference signal, the receiving end can obtain the time of receiving the second reference signal. The receiving end can determine the time difference between the first reference signal and the second reference signal according to the clock signal generated by the frame, namely, determine the first time difference. The receiving end can determine the frequency offset estimation value according to the first time difference and the second time difference.

The first time difference is obtained by timing according to the crystal oscillator of the receiving end; and the second time difference is obtained by timing according to the crystal oscillator of the transmitting end. If both crystal oscillators are accurate, the first time difference can be equal to the second time difference; if there is a difference between the two crystal oscillators, typically, the crystal oscillation deviation of the receiving end is larger, the first time difference is not equal to the second time difference.

Alternatively, according to the formulaThe normalized crystal oscillator frequency difference can be calculated, wherein sigma is the normalized crystal oscillator frequency difference, T ₂ For a second time difference, T ₁ Is the first time difference. Further, the frequency offset estimation value Δf may be according to Δf=f _c Sigma, where f _c Is the target frequency for down-conversion.

For example, fig. 19 shows a schematic diagram in which a transmitting end transmits a first reference signal and a second reference signal, i.e., two reference signals, to a receiving end. Assuming that the two reference signals are OOK modulated, both reference signals modulate the sequence "1010", it should be understood that this is only an example and is not limiting of the present application.

Before transmitting the two reference signals, the transmitting end informs the receiving end of the time difference between the two transmission of the reference signals, and in the example shown in fig. 19, the two reference signals are separated by 36 OFDM symbols. In addition, the transmitting end informs the receiving end that the sequence of the reference signal transmitted twice is '1010'.

After receiving the signal, the receiving end performs down-conversion processing, filtering processing, and performing envelope detection on the filtered signal, and then the receiving end searches the sequence 1010 in the envelope signal, for example, the receiving end performs sliding correlation operation through a local correlator to realize the sequence 1010 in the envelope signal. When the receiver finds two reference signals, it can determine the time of reception and calculate the time difference between the two. Because the local time is calculated by the clock signal generated by the local oscillator, if the local oscillator has frequency drift, the time difference calculated locally and the time difference notified by the transmitting end will have difference. For example, the sending end informs that the time difference between the two reference signals is 36 OFDM symbols, but the receiving end calculates that the time difference is 37 OFDM symbols, which indicates that the frequency of the crystal oscillator of the receiving end is higher than that of the crystal oscillator of the sending end, and the normalized crystal oscillator frequency difference can be (37-36)/36. Thus, the receiving end can calculate the frequency offset existing in the local crystal oscillator.

By the method, the receiving end can determine the frequency offset estimation value, and further compensate the frequency of the carrier signal local to the receiving end so as to reduce or eliminate the frequency offset.

As a possible example, to make the frequency offset estimation more accurate, the receiving end may implement signal reception and frequency offset estimation based on the receiver shown in fig. 20. In this case, two intermediate frequency filters, such as BPF1 and BPF2 in fig. 20, may be provided, and the frequency ranges of BPF1 and BPF2 are different. Optionally, the frequency range of BPF1 is smaller than the frequency range of BPF 2. The BPF1 is used to receive a reference signal (e.g., the first reference signal described above). The BPF2 is for receiving a signal of the first channel. The output of the envelope detection module is used for frequency offset estimation, and the carrier signal of the local crystal oscillator is adjusted according to the result of the frequency offset estimation module so as to compensate the existing frequency offset. Thus, the reference signal is received by the intermediate frequency filter with a smaller frequency range, other interference signals received by the intermediate frequency filter can be avoided, and the accuracy of frequency offset estimation is improved.

Based on the above embodiments, the present embodiment also provides a communication apparatus, and referring to fig. 21, a communication apparatus 2100 may include a transceiver unit 2101 and a processing unit 2102. The transceiver 2101 is configured to receive information (signals, messages, or data) or transmit information (signals, messages, or data) from the communication device 2100, and the processing unit 2102 is configured to control and manage operations of the communication device 2100. The processing unit 2102 may also control the steps performed by the transceiver unit 2101.

The communication apparatus 2100 may specifically be a receiving terminal, a processor in the receiving terminal, or a chip system, or a functional module, or the like in the above-described embodiments; alternatively, the communication apparatus 2100 may specifically be a transmitting end, a processor of the transmitting end, or a chip system, or a functional module, or the like in the above embodiments.

In one embodiment, when the communication apparatus 2100 is configured to implement the function of the receiving end in the embodiment shown in fig. 8, the method specifically may include: the transceiver unit 2101 may be configured to receive a first reference signal sent by a transmitting end, where the first reference signal is used for frequency offset estimation, a frequency domain range of the first reference signal is greater than a frequency domain range of a first channel, and the frequency domain range of the first reference signal includes the frequency domain range of the first channel; the processing unit 2102 may be configured to determine a frequency offset estimation value according to the first reference signal, and perform frequency offset correction according to the frequency offset estimation value; the transceiver unit 2101 may be further configured to receive a signal sent by the transmitting end on the first channel based on a result of frequency offset correction.

In an alternative embodiment, the first reference signal may be a signal whose frequency varies linearly with time.

Illustratively, the processing unit 2102, when determining the frequency offset estimate from the first reference signal, is configured to: filtering the first reference signal to obtain a filtered reference signal; performing envelope detection on the filtered reference signal to obtain a first envelope signal; and determining the frequency offset estimation value according to the time difference between amplitude peaks of the first envelope signal.

Optionally, the processing unit 2102 is configured to, when determining the frequency offset estimation value according to a time difference between amplitude peaks of the first envelope signal: determining a first frequency according to the time difference between amplitude peaks of the first envelope signal, the sending duration of the first reference signal, the lowest frequency of the first reference signal and the slope of the first reference signal, wherein the first frequency is the frequency with frequency deviation; and determining the frequency offset estimation value according to the first frequency and the second frequency, wherein the second frequency is the frequency without frequency offset.

In another alternative embodiment, the first reference signal may be at least one OOK modulated sequence carried on at least one sub-band, each of the at least one sub-band including at least one sub-carrier, each of the at least one sub-band carrying at least one OOK modulated sequence.

Illustratively, the processing unit 2102, when determining the frequency offset estimate from the first reference signal, is configured to: filtering the first reference signal to obtain a filtered reference signal; performing envelope detection on the filtered reference signal to obtain a second envelope signal; demodulating the second envelope signal to obtain a demodulated signal; determining a first sub-band corresponding to the demodulated signal; and determining the frequency offset estimation value according to the first sub-band and a second sub-band, wherein the second sub-band is a sub-band without frequency offset, and the at least one sub-band comprises the second sub-band.

In an example, the transceiver unit 2101 may be further configured to receive a second reference signal sent by the sending end, where the second reference signal is used for frequency offset estimation; further, the processing unit 2102 is configured to, when determining the frequency offset estimation value according to the first reference signal: and determining the frequency offset estimation value according to the first reference signal and the second reference signal.

Optionally, the processing unit 2102 is configured to, when determining the frequency offset estimation value according to the first reference signal and the second reference signal: determining a first time difference, wherein the first time difference is a time difference between the receiving of the first reference signal and the receiving of the second reference signal by the receiving and transmitting unit 2101; and determining the frequency offset estimation value according to the first time difference and the second time difference, wherein the second time difference is the time difference between the sending end sending the first reference signal and the second reference signal.

In a possible manner, the transceiver unit 2101 may also be configured to receive the second time difference sent by the sender.

In another embodiment, when the communication apparatus 2100 is configured to implement the function of the transmitting end in the embodiment shown in fig. 8, the method specifically may include: the transceiver unit 2101 may be configured to send a first reference signal to a receiving end, where the first reference signal is used for frequency offset estimation; the frequency domain range of the first reference signal is greater than the frequency domain range of the first channel, and the frequency domain range of the first reference signal comprises the frequency domain range of the first channel; and transmitting a signal to the receiving end on the first channel; the processing unit 2102 may be configured to control the transceiver unit 2101 to perform a transceiver operation.

In an alternative embodiment, the first reference signal may be a signal whose frequency varies linearly with time.

In another alternative embodiment, the first reference signal may be at least one on-off keying OOK modulated sequence carried on at least one sub-band, each of the at least one sub-band including at least one sub-carrier, each of the at least one sub-band carrying one OOK modulated sequence.

Illustratively, the transceiver unit 2101 may be further configured to send a second reference signal to the receiving end, where the second reference signal is used for frequency offset estimation.

Optionally, the transceiver unit 2101 may be further configured to send a second time difference to the receiving end, where the second time difference is a time difference between sending the first reference signal and sending the second reference signal.

It should be noted that, in the embodiment of the present application, the division of the units is schematic, which is merely a logic function division, and other division manners may be implemented in actual practice. The functional units in the embodiments of the present application may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit. The integrated units may be implemented in hardware or in software functional units.

The integrated units, if implemented in the form of software functional units and sold or used as stand-alone products, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application may be embodied in essence or a part contributing to the prior art or all or part of the technical solution, in the form of a software product stored in a storage medium, including several instructions to cause a computer device (which may be a personal computer, a server, or a network device, etc.) or a processor (processor) to perform all or part of the steps of the methods described in the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a read-only memory (ROM), a random access memory (random access memory, RAM), a magnetic disk, or an optical disk, or other various media capable of storing program codes.

Based on the above embodiments, the present application also provides a communication device, and referring to fig. 22, the communication device 2200 may include a transceiver 2201 and a processor 2202. Optionally, the communication device 2200 may further include a memory 2203 therein. The memory 2203 may be provided inside the communication device 2200 or may be provided outside the communication device 2200. Wherein the processor 2202 may control the transceiver 2201 to receive and transmit signals, information, messages or data, etc.

In particular, the processor 2202 may be a central processing unit (central processing unit, CPU), a network processor (network processor, NP) or a combination of CPU and NP. The processor 2202 may further comprise a hardware chip. The hardware chip may be an application-specific integrated circuit (ASIC), a programmable logic device (programmable logic device, PLD), or a combination thereof. The PLD may be a complex programmable logic device (complex programmable logic device, CPLD), a field-programmable gate array (field-programmable gate array, FPGA), general-purpose array logic (generic array logic, GAL), or any combination thereof.

Wherein the transceiver 2201, the processor 2202 and the memory 2203 are interconnected. Optionally, the transceiver 2201, the processor 2202 and the memory 2203 are connected to each other by a bus 2204; the bus 2204 may be a peripheral component interconnect standard (Peripheral Component Interconnect, PCI) bus or an extended industry standard architecture (Extended Industry Standard Architecture, EISA) bus, among others. The buses may be classified as address buses, data buses, control buses, etc. For ease of illustration, only one thick line is shown in fig. 22, but not only one bus or one type of bus.

In an alternative embodiment, the memory 2203 is configured to store a program or the like. In particular, the program may include program code including computer-operating instructions. The memory 2203 may include RAM, and may also include non-volatile memory (non-volatile memory), such as one or more magnetic disk memory. The processor 2202 executes the application program stored in the memory 2203 to realize the functions described above, thereby realizing the functions of the communication device 2200.

Illustratively, the communication apparatus 2200 may be a network device in the above-described embodiment; but also the first terminal device in the above embodiment.

In one embodiment, the transceiver 2201 may implement the transceiving operation performed by the receiving end in the embodiment shown in fig. 8 when the communication device 2200 implements the function of the receiving end in the embodiment shown in fig. 8; the processor 2202 may implement operations other than the transceiving operations performed by the receiving end in the embodiment illustrated in fig. 8. Specific details of the foregoing are set forth in the embodiment of fig. 8, and will not be described in detail herein. Alternatively, the transceiver 2201 may include a receiver as shown in fig. 18.

In another embodiment, the transceiver 2201 may implement the transceiving operation performed by the transmitting end in the embodiment shown in fig. 8 when the communication device 2200 implements the function of the transmitting end in the embodiment shown in fig. 8; the processor 2202 may implement operations other than the transceiving operations performed by the transmitting end in the embodiment illustrated in fig. 8. Specific details of the foregoing are set forth in the embodiment of fig. 8, and will not be described in detail herein.

Based on the above embodiments, the embodiments of the present application provide a communication system, which may include a transmitting end, a receiving end, and the like, to which the above embodiments relate.

The embodiment of the application also provides a computer readable storage medium, which is used for storing a computer program, and when the computer program is executed by a computer, the computer can implement the communication method provided by the embodiment of the method.

The embodiment of the application also provides a computer program product, which is used for storing a computer program, and when the computer program is executed by a computer, the computer can implement the communication method provided by the embodiment of the method.

The embodiment of the application also provides a chip, which comprises a processor, wherein the processor is coupled with the memory and is used for calling the program in the memory so that the chip can realize the communication method provided by the embodiment of the method.

The embodiment of the application also provides a chip which is coupled with the memory and is used for realizing the communication method provided by the embodiment of the method.

It will be appreciated by those skilled in the art that embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to the application. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present application without departing from the scope of the application. Thus, if such modifications and variations of the present application fall within the scope of the claims and the equivalents thereof, the present application is intended to cover such modifications and variations.