Filtering implementation method, device and system based on orthogonal frequency division multiplexing

Abstract

The invention provides a filtering implementation method, device and system based on orthogonal frequency division multiplexing. The method comprises the steps that a sending end obtains data to be transmitted; based on each sub-band, according to a modulation mode and a resource mapping mode corresponding to a transmission rate of an orthogonal frequency division multiplexing filtering (F-OFDM) system, performing resource mapping on data of the sub-band to obtain mapped data; according to the frequency domain occupation position of the sub-band, carrying out frequency shifting on the time domain filtering coefficient of the baseband filter to generate a time domain coefficient of the sub-band filter; performing frequency domain filtering processing on the mapped sub-band data by adopting a time domain coefficient of a sub-band filter to obtain the sub-band data; and sending the sub-band data of each sub-band. According to the method, the defects of filter research of the conventional narrowband orthogonal frequency division multiplexing filtering system can be overcome, and discrete narrowband spectrum resources can be effectively utilized.

Description

Technical Field

[0001] The present invention relates to the field of communication technology, and in particular to a filtering implementation method, device and system based on orthogonal frequency division multiplexing. Background Art

[0002] The F-OFDM (Filtered Orthogonal Frequency Division Multiplexing) waveform is an orthogonal multi-carrier technology that is based on the OFDM (Orthogonal Frequency Division Multiplexing) waveform and performs filtering operations on the sub-bands at both the transmitting and receiving ends. It not only takes into account the technical advantages of OFDM, but also meets the requirements of 5G (5th Generation Mobile Communication Technology) for physical layer waveforms.

[0003] The basic principle of F-OFDM is to divide the frequency band of the system into multiple sub-bands, and then perform symbol modulation, OFDM modulation, add CP (Cyclic Prefix) and other operations respectively. The main difference between it and the OFDM system is that: each sub-band at the transmitting end is filtered by a sub-band filter to achieve coupled transmission of sub-band signals; the receiving end filters the received coupled signals through a matched filter to decouple them into corresponding sub-band signals. Each sub-band of the F-OFDM system can be considered to be non-overlapping, so it has very small spectrum leakage. While improving the system spectrum efficiency, it can also use scattered spectrum to achieve the purpose of coexistence with other waveforms. F-OFDM can dynamically configure bandwidth, CP length, subcarrier spacing, FFT (Fast Fourier Transformation) points and other appropriate waveform parameters for each sub-band according to the actual needs of the business, which improves the flexibility and scalability of the 5G communication system.

[0004] Existing research on F-OFDM system filter design is based on broadband F-OFDM systems in the public network frequency band. Research on narrowband F-OFDM system filter design is still very lacking, resulting in the inability to fully utilize discrete narrowband spectrum. Summary of the invention

[0005] In order to overcome the above-mentioned lack of research on narrowband F-OFDM system filter design, which leads to the defect that discrete narrowband spectrum cannot be fully utilized, in a first aspect, the present invention provides a filtering implementation method based on orthogonal frequency division multiplexing, the method comprising:

[0006] Acquire data to be transmitted, the data corresponding to data of multiple sub-bands;

[0007] Based on each sub-band, according to the modulation mode and resource mapping mode corresponding to the transmission rate of the F-OFDM system, resource mapping is performed on the data of the sub-band to obtain mapped data; according to the frequency domain occupied position of the sub-band, the time domain filter coefficient of the baseband filter is frequency shifted to generate the time domain coefficient of the sub-band filter; using the time domain coefficient of the sub-band filter, frequency domain filtering is performed on the mapped sub-band data to obtain sub-band data;

[0008] Subband data for each subband is sent.

[0009] Optionally, the process of determining the modulation mode and resource mapping mode corresponding to the transmission rate of the F-OFDM system includes:

[0010] Calculate the modulation mode according to the transmission rate, symbol transmission rate and channel coding rate required by the F-OFDM system, wherein the modulation mode includes 256QAM, 64QAM, 16QAM and QPSK;

[0011] When the modulation mode is 256QAM, determining the resource mapping mode to be the first mode;

[0012] When the modulation mode is 64QAM, determining the resource mapping mode to be the second mode;

[0013] When the modulation mode is 16QAM, determining the resource mapping mode to be the third mode;

[0014] When the modulation mode is QPSK, determining the resource mapping mode to be the fourth mode;

[0015] The first mode, the second mode, the third mode and the fourth mode correspond to different DMRS configurations respectively.

[0016] Optionally, in the first mode: if a single subband is used for data transmission, then in the single subband, there is one subcarrier on each side edge of the odd-numbered symbol that does not perform data transmission or pilot transmission, one carrier on the secondary edge uses 64QAM modulation for data transmission, and the remaining subcarriers use 256QAM modulation for data transmission, and two subcarriers on each side edge of the even-numbered symbol do not perform data transmission or pilot transmission, and the remaining subcarriers transmit DMRS pilots for channel estimation; if multiple subbands are merged for data transmission, then in the merged subband, two subcarriers on each side edge of the odd-numbered symbol use 64QAM modulation for data transmission, and the remaining subcarriers use 256QAM modulation for data transmission, one subcarrier on each side edge of the even-numbered symbol does not perform data transmission or pilot transmission, the three subcarriers located in the middle use 256QAM modulation for data transmission, and the remaining subcarriers transmit DMRS pilots for channel estimation;

[0017] In the second mode: if a single subband is used for data transmission, then in the single subband, one subcarrier on each side edge of the odd-numbered symbol uses 16QAM modulation for data transmission, and the remaining subcarriers use 64QAM modulation for data transmission, and one subcarrier on each side edge of the even-numbered symbol does not perform data transmission or pilot transmission, and the remaining subcarriers transmit DMRS pilots for channel estimation; if multiple subbands are merged for data transmission, then in the merged subband, one subcarrier on each side edge of the odd-numbered symbol uses 16QAM modulation for data transmission, and the remaining subcarriers use 64QAM modulation for data transmission, one subcarrier on each side edge of the even-numbered symbol does not perform data transmission or pilot transmission, the three subcarriers located in the middle use 64QAM modulation for data transmission, and the remaining subcarriers transmit DMRS pilots for channel estimation;

[0018] In the third mode: if a single subband is used for data transmission, then in the single subband, all subcarriers of the odd-numbered symbols use 16QAM modulation for data transmission, and one subcarrier on each side edge of the even-numbered symbol does not perform data transmission or pilot transmission, and the remaining subcarriers transmit DMRS pilots for channel estimation; if multiple subbands are combined for data transmission, then in the combined subband, all subcarriers of the odd-numbered symbols use 16QAM modulation for data transmission; one subcarrier on each side edge of the even-numbered symbol does not perform data transmission or pilot transmission, and the three subcarriers located in the middle use 16QAM modulation for data transmission, and the remaining subcarriers transmit DMRS pilots for channel estimation;

[0019] In the fourth mode: if a single subband is used for data transmission, then in the single subband, all subcarriers of the odd-numbered symbols use QPSK modulation for data transmission, and there is one subcarrier on each side edge of the even-numbered symbols without data transmission or pilot transmission, and the remaining subcarriers transmit DMRS pilots for channel estimation; if multiple subbands are merged for data transmission, then in the merged subband, all subcarriers of the odd-numbered symbols use QPSK modulation for data transmission, and there is one subcarrier on each side edge of the even-numbered symbols without data transmission or pilot transmission, the three subcarriers located in the middle use QPSK modulation for data transmission, and the remaining subcarriers transmit DMRS pilots for channel estimation.

[0020] Optionally, the process of acquiring the time domain filter coefficient of the baseband filter includes:

[0021] The impulse response of the linear phase filter is truncated by using a Kaiser window as a truncation window to obtain a time domain filter coefficient of a baseband filter. The time domain filter coefficient includes the length of the baseband filter and the shape parameter of the Kaiser window function.

[0022] Optionally, after the Kaiser window is used as the truncation window to truncate the impulse response of the linear phase filter to obtain the time domain filter coefficient of the baseband filter, the method further includes:

[0023] Based on the error vector magnitude (EVM) performance requirement of the F-OFDM system, the time domain filter coefficients on both sides of the time domain filter coefficients of the baseband filter are intercepted;

[0024] Different modulation modes have different EVM performance requirements.

[0025] Optionally, frequency shifting the time domain filter coefficients of the baseband filter according to the frequency domain occupied position of the subband to generate the time domain coefficients of the subband filter includes:

[0026] Calculate the center frequency of the sub-band according to the frequency domain occupied position of the sub-band, the time domain filter coefficient of the baseband filter and the center frequency calculation formula of the sub-band;

[0027] The time domain coefficient of the sub-band filter is calculated according to the center frequency of the sub-band and the time domain coefficient calculation formula of the sub-band.

[0028] Optionally, assume that the frequency domain occupied positions of each subband are the first subband and the second subband respectively, the total number of subcarriers on the first subband is M1, and the number of all subcarriers is [K min ,K max], the number of protection carriers with a frequency interval of the first subband being the spacing is N1, the total number of subcarriers on the second subband is M2, and the number of protection carriers with a frequency interval of the second subband being the spacing is N2; when the subband is the first subband, the calculation formula for the center frequency of the subband is as follows:

[0029]

[0030] When the sub-band is the second sub-band, the calculation formula of the center frequency of the sub-band refers to the following formula:

[0031] F2=(K max +N1)*Δf1+(N2+M2 / 2+0.5)*Δf2, where K max +N1 is an even number, F1 is the center frequency of the first sub-band, F2 is the center frequency of the second sub-band, Δf1 and Δf2 are the bandwidths;

[0032] When the sub-band is the first sub-band, the time domain coefficient calculation formula of the sub-band refers to the following formula:

[0033]

[0034] When the sub-band is the first sub-band, the time domain coefficient calculation formula of the sub-band refers to the following formula:

[0035] Where f1(n) is the time domain coefficient of the first subband, f2(n) is the time domain coefficient of the second subband, f(n) is the value of the original signal at the nth sampling point, j is the imaginary unit, and L is the total number of sampling points.

[0036] Optionally, the using the time domain coefficient of the sub-band filter to perform frequency domain filtering on the mapped sub-band data to obtain the sub-band data includes:

[0037] Segmenting the mapped data to obtain a plurality of data signal segments;

[0038] Converting the time domain coefficients of the subband filter into frequency domain coefficients, and converting each of the data signal segments into a frequency domain data signal;

[0039] Multiply each frequency domain data signal by the corresponding frequency domain coefficient in the frequency domain to obtain each filtered frequency domain data signal;

[0040] Each filtered frequency domain data signal is connected to obtain sub-band data.

[0041] Optionally, segmenting the mapped data to obtain a plurality of data signal segments includes:

[0042] Performing a 0-padding operation before the mapped data to obtain 0-padding data;

[0043] Divide the data padded with 0 into a plurality of data segments of length M;

[0044] Starting from the second data segment with a length of M, the last L-1 data signals of the previous data segment are added before each data segment with a length of M to obtain multiple data signal segments with a length of M+L-1.

[0045] Optionally, the connecting each filtered frequency domain data signal to obtain sub-band data includes:

[0046] In each of the filtered frequency domain data signals, starting from the second filtered frequency domain data signal, discard L-1 data before each filtered frequency domain data signal to obtain a plurality of data segments with a length of M;

[0047] The multiple data segments with a length of M are connected to obtain sub-band data.

[0048] In a second aspect, the present invention further provides a communication device, comprising:

[0049] A processing module is used to obtain data to be transmitted, the data corresponding to multiple sub-bands; based on each sub-band, according to the modulation mode and resource mapping mode corresponding to the transmission rate of the F-OFDM system, perform resource mapping on the data of the sub-band to obtain mapped data; according to the frequency domain occupied position of the sub-band, perform frequency shift on the time domain filter coefficient of the baseband filter to generate the time domain coefficient of the sub-band filter; use the time domain coefficient of the sub-band filter to perform frequency domain filtering on the mapped sub-band data to obtain sub-band data;

[0050] The communication module is used to send sub-band data of each sub-band.

[0051] In a third aspect, the present invention further provides a filtering implementation method based on orthogonal frequency division multiplexing, comprising:

[0052] Acquire received data; the data corresponds to received data of multiple sub-bands;

[0053] Based on each sub-band, performing matched filtering and demapping processing on the received data of the sub-band to obtain original data;

[0054] The received data is obtained by performing resource mapping on the data of the subband based on each subband at the transmitting end according to the modulation mode and resource mapping mode corresponding to the transmission rate of the F-OFDM system, and obtaining the mapped data; performing frequency shifting on the time domain filter coefficient of the baseband filter according to the frequency domain occupied position of the subband to generate the time domain coefficient of the subband filter; and performing frequency domain filtering on the mapped subband data using the time domain coefficient of the subband filter to obtain the subband data and then sending it.

[0055] Optionally, performing matched filtering on the received data of the subband includes:

[0056] According to the frequency domain occupied position of the sub-band, using the matched filter of the sub-band to perform matched filtering processing on the received data of the sub-band;

[0057] When the sub-band is the first sub-band, the matched filter of the sub-band refers to the following formula:

[0058] g1(n)=f1 * (Ln-1),n∈[0,L-1],

[0059] When the sub-band is the first sub-band, the matched filter refers to the following formula:

[0060] Where g1(n) is the matched filter of the first subband, g2(n) is the matched filter of the second subband, and f1 * is the conjugate of the time domain coefficient of the first subband, is the conjugate of the time domain coefficient of the second subband, n is the value at the nth sampling point, and L is the total number of sampling points.

[0061] In a fourth aspect, the present invention further provides a communication device, comprising:

[0062] A communication device, configured to obtain received data; the data corresponding to received data of a plurality of sub-bands;

[0063] A processing device, configured to perform matched filtering and demapping processing on the received data of each sub-band to obtain original data;

[0064] The received data is obtained by performing resource mapping on the data of the subband based on each subband at the transmitting end according to the modulation mode and resource mapping mode corresponding to the transmission rate of the F-OFDM system, and obtaining the mapped data; performing frequency shifting on the time domain filter coefficient of the baseband filter according to the frequency domain occupied position of the subband to generate the time domain coefficient of the subband filter; and performing frequency domain filtering on the mapped subband data using the time domain coefficient of the subband filter to obtain the subband data and then sending it.

[0065] In a fifth aspect, the present invention further provides a communication system, comprising a transmitting end and a receiving end; the transmitting end is used to implement the filtering implementation method based on orthogonal frequency division multiplexing described in the first aspect above, and the receiving end is used to implement the filtering implementation method based on orthogonal frequency division multiplexing described in the third aspect above.

[0066] In a sixth aspect, the present invention further provides an electronic device, comprising: at least one processor and a memory; the memory and the processor are connected via a bus;

[0067] The memory is used to store one or more programs;

[0068] When the one or more programs are executed by the at least one processor, the filtering implementation method based on orthogonal frequency division multiplexing described in any one of the first aspects above is implemented, or the filtering implementation method based on orthogonal frequency division multiplexing described in any one of the third aspects above is implemented.

[0069] In a seventh aspect, the present invention further provides a readable storage medium having an execution program stored thereon, which, when executed, implements the filtering implementation method based on orthogonal frequency division multiplexing described in any one of the first aspect above, or implements the filtering implementation method based on orthogonal frequency division multiplexing described in any one of the third aspect above.

[0070] Compared with the prior art, the present invention has the following beneficial effects:

[0071] The present invention provides a filtering implementation method based on orthogonal frequency division multiplexing, comprising: a transmitting end obtains data to be transmitted, the data corresponding to data of multiple sub-bands; based on each sub-band, according to the modulation mode and resource mapping mode corresponding to the transmission rate of the F-OFDM system, resource mapping is performed on the data of the sub-band to obtain mapped data; according to the frequency domain occupied position of the sub-band, the time domain filter coefficient of the baseband filter is frequency shifted to generate the time domain coefficient of the sub-band filter; the time domain coefficient of the sub-band filter is used to perform frequency domain filtering processing on the mapped sub-band data to obtain sub-band data; the sub-band data of each sub-band is sent, and correspondingly, the receiving end obtains the received data; the data corresponds to the received data of multiple sub-bands; based on each sub-band, the received data of the sub-band is matched filtered and de-mapped to obtain the original data. The present invention can reduce the influence of filtering on data transmission performance while reducing the complexity of filtering implementation through flexible resource mapping combined with multiple modulation modes, and can effectively reduce the implementation complexity of the filtering process by designing the time domain coefficients and frequency domain filtering of the sub-band filter, which can make up for the shortcomings of the current research on filters of narrow-band orthogonal frequency division multiplexing filtering systems and can effectively utilize discrete narrow-band spectrum resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] Figure 1It is a flow chart of a filtering implementation method based on orthogonal frequency division multiplexing of the present invention;

[0073] Figure 2 It is a schematic diagram of the sending end process of the present invention;

[0074] Figure 3 A schematic diagram of the time domain filter coefficients of the filter of the present invention;

[0075] Figure 4 It is a schematic diagram of frequency domain filtering operation data segmentation of the present invention;

[0076] Figure 5 A schematic diagram of frequency domain filtering operation data merging of the present invention;

[0077] Figure 6 A schematic diagram of the filtering process of the present invention;

[0078] Figure 7 It is a schematic diagram of the structure of the communication system of the present invention;

[0079] Figure 8 It is a schematic diagram of the structure of the communication device of the present invention;

[0080] Fig. 9 It is a schematic structural diagram of the electronic device of the present invention. DETAILED DESCRIPTION

[0081] The specific implementation modes of the present invention are further described in detail below with reference to the accompanying drawings.

[0082] Embodiment 1:

[0083] The present invention provides a filtering implementation method based on orthogonal frequency division multiplexing, the flow chart of which is as follows: Figure 1 As shown, including:

[0084] Step 101: The transmitting end obtains data to be transmitted, and the data corresponds to data of multiple sub-bands.

[0085] Step 102: The transmitter performs resource mapping on the subband data based on each subband according to the modulation mode and resource mapping mode corresponding to the transmission rate of the F-OFDM system to obtain mapped data; frequency-shifts the time domain filter coefficients of the baseband filter according to the frequency domain occupied position of the subband to generate the time domain coefficients of the subband filter; and uses the time domain coefficients of the subband filter to perform frequency domain filtering on the mapped subband data to obtain the subband data.

[0086] Step 103: the transmitting end sends sub-band data of each sub-band, and correspondingly, the receiving end obtains received data; the data corresponds to received data of multiple sub-bands.

[0087] The received data is obtained by performing resource mapping on the sub-band data based on each sub-band by the transmitter according to the modulation mode and resource mapping mode corresponding to the transmission rate of the F-OFDM system, and obtaining the mapped data; performing frequency shift on the time domain filter coefficient of the baseband filter according to the frequency domain occupied position of the sub-band to generate the time domain coefficient of the sub-band filter; using the time domain coefficient of the sub-band filter, performing frequency domain filtering on the mapped sub-band data, and obtaining the sub-band data before sending.

[0088] Step 104: The receiving end performs matched filtering and demapping processing on the received data of each sub-band to obtain original data.

[0089] The embodiments of the present invention can reduce the complexity of filtering implementation and the impact of filtering on data transmission performance through flexible resource mapping combined with multiple modulation methods. By designing the time domain coefficients and frequency domain filtering of the subband filter, the implementation complexity of the filtering process can be effectively reduced, which can make up for the shortcomings of the current research on narrowband F-OFDM system filters and effectively utilize discrete narrowband spectrum resources.

[0090] In one usage scenario, a narrowband communication system refers to a communication system with a continuous available bandwidth below 4 MHz (megahertz). The frequency band location of the communication system can be located in, but not limited to, the 230 MHz frequency band. Subbands 1 to n in the narrowband communication system correspond to the discrete spectrum requirements of the communication system.

[0091] The sending process is as follows Figure 2 As shown, it mainly includes modules such as bit coding, modulation, resource mapping, OFDM modulation and filtering, and its receiving end process is the inverse process of the sending end process.

[0092] Considering the characteristics of narrowband resources, there may be large interference, so in the embodiment of the present invention, a design method of multiple resource modes can be adopted to determine the modulation mode order and resource mapping mode adopted according to the system transmission rate requirements. In one implementation, the process of determining the modulation mode and resource mapping mode corresponding to the transmission rate of the F-OFDM system in step 102 includes:

[0093] Calculate the modulation mode according to the transmission rate, symbol transmission rate and channel coding rate required by the F-OFDM system. The modulation modes include 256QAM (Quadrature Amplitude Modulation), 64QAM, 16QAM and QPSK (Quadrature Phase Shift Keying).

[0094] When the modulation mode is 256QAM, the resource mapping mode is determined to be the first mode (hereinafter referred to as mode 1);

[0095] When the modulation mode is 64QAM, the resource mapping mode is determined to be the second mode (hereinafter referred to as mode 2);

[0096] When the modulation mode is 16QAM, the resource mapping mode is determined to be the third mode (hereinafter referred to as mode 3);

[0097] When the modulation mode is QPSK, determining the resource mapping mode to be the fourth mode (hereinafter referred to as mode 4);

[0098] The first mode, the second mode, the third mode and the fourth mode correspond to different DMRS (Demodulation Reference Signal, modulation reference signal) configurations respectively.

[0099] The modulation method is also called the modulation order or data modulation method, which can be calculated by the following formula:

[0100] Where P is the channel coding rate of the communication system, R is the transmission rate required by the communication system, and N is the symbol transmission rate. The resource mapping modes corresponding to different modulation methods are shown in Table 1:

[0101] Table 1

[0102] Modulation Resource Mapping Mode Number 256QAM Mode 1 64QAM Mode 2 16QAM Mode 3 QPSK Mode 4

[0103] Each resource mapping mode is described below:

[0104] Assuming that each time slot has M OFDM symbols (M is an even number), the 1st, 3rd...M-3, M-1st symbols are mainly used for data transmission of different modulation modes, and the 2nd, 4th...M-2, M symbols are mainly used for transmitting DMRS pilot for channel estimation.

[0105] In the first mode:

[0106] If a single subband is used for data transmission, then in the single subband, there is one subcarrier on each side edge of the odd-numbered symbol that does not perform data transmission or pilot transmission, one carrier on the secondary edge uses 64QAM modulation for data transmission, and the remaining subcarriers use 256QAM modulation for data transmission, and there are two subcarriers on each side edge of the even-numbered symbol that do not perform data transmission or pilot transmission (the design of subcarriers that do not perform data transmission or pilot transmission can ensure that the data subcarriers with the same symbol as DMRS will not interfere with the reference signal subcarriers. This effect also exists in subsequent similar designs and is not pointed out one by one). The remaining subcarriers transmit DMRS pilots for channel estimation; that is, for a single subband, the 1st, 3rd...M-3, and M-1st symbols use the same resource mapping method: one subcarrier is left blank at the edges of both sides for no data or pilot transmission, one subcarrier at the secondary edge uses 64QAM modulation for data transmission, and the remaining subcarriers use 256QAM modulation for data transmission; the 2nd, 4th...M-2, and M symbols use the same resource mapping method: two subcarriers are left blank at the edges of both sides for no data or pilot transmission, and the remaining subcarriers are used to transmit DMRS pilots for channel estimation.

[0107] If multiple subbands are combined for data transmission, then in the combined subband, two subcarriers on both sides of the odd-numbered symbol use 64QAM modulation for data transmission, and the remaining subcarriers use 256QAM modulation for data transmission, one subcarrier on both sides of the even-numbered symbol does not transmit data or pilot, the three subcarriers in the middle use 256QAM modulation for data transmission, and the remaining subcarriers transmit DMRS pilots for channel estimation; that is, for multi-subband combined transmission, the 1st, 3rd...M-3, M-1st symbols use the same resource mapping method: two subcarriers on both sides of the edge use 64QAM modulation for data transmission, and the other subcarriers use 256QAM modulation for data transmission; the 2nd, 4th...M-2, M symbols use the same resource mapping method: one subcarrier on each side edge is left empty for no data or pilot transmission, the three middle subcarriers use 256QAM modulation for data transmission, and the remaining subcarriers are used to transmit DMRS pilots for channel estimation.

[0108] In the second mode:

[0109] If a single subband is used for data transmission, then in the single subband, one subcarrier on each side edge of the odd-numbered symbol uses 16QAM modulation for data transmission, and the remaining subcarriers use 64QAM modulation for data transmission, one subcarrier on each side edge of the even-numbered symbol does not perform data transmission or pilot transmission, and the remaining subcarriers transmit DMRS pilots for channel estimation; that is, for a single subband, the 1st, 3rd...M-3, and M-1st symbols use the same resource mapping method: one subcarrier on each side edge uses 16QAM modulation for data transmission, and the remaining subcarriers use 64QAM modulation for data transmission; the 2nd, 4th...M-2, and M symbols use the same resource mapping method: one subcarrier on each side edge is left empty for no data or pilot transmission, and the remaining subcarriers are used to transmit DMRS pilots for channel estimation.

[0110] If multiple subbands are combined for data transmission, then in the combined subband, one subcarrier on each side edge of the odd-numbered symbol uses 16QAM modulation for data transmission, and the remaining subcarriers use 64QAM modulation for data transmission, one subcarrier on each side edge of the even-numbered symbol does not transmit data or pilot, the three subcarriers located in the middle use 64QAM modulation for data transmission, and the remaining subcarriers transmit DMRS pilots for channel estimation; that is, for multi-subband combined transmission, the 1st, 3rd...M-3, M-1st symbols use the same resource mapping method: one subcarrier on each side edge uses 16QAM modulation for data transmission, and the remaining subcarriers use 64QAM modulation for data transmission; the 2nd, 4th...M-2, M symbols use the same resource mapping method: one subcarrier on each side edge is left empty for no data or pilot transmission, the three middle subcarriers use 64QAM modulation for data transmission, and the remaining subcarriers are used to transmit DMRS pilots for channel estimation.

[0111] In the third mode:

[0112] If a single subband is used for data transmission, then in the single subband, all subcarriers of the odd-numbered symbols use 16QAM modulation for data transmission, and there is one subcarrier on each side edge of the even-numbered symbols that does not perform data transmission or pilot transmission, and the remaining subcarriers transmit DMRS pilots for channel estimation. In addition to this example, there is another possible example in which all subcarriers of the even-numbered symbols transmit DMRS pilots for channel estimation; that is, for a single subband, the 1st, 3rd...M-3, M-1 symbols use the same resource mapping method: all subcarriers use 16QAM modulation for data transmission; the 2nd, 4th...M-2, M symbols use the same resource mapping method: there is one subcarrier on each side edge of the 2nd, 4th...M-2, M symbols that does not perform data transmission or pilot transmission, and the remaining subcarriers transmit DMRS pilots for channel estimation. Accordingly, in addition to this example, there is another possible example in which all subcarriers are used to transmit DMRS pilots for channel estimation.

[0113] If multi-subband merging is used for data transmission, then in the merged subband, all subcarriers of the odd-numbered symbols use 16QAM modulation for data transmission; one subcarrier on each side edge of the even-numbered symbol does not perform data transmission or pilot transmission, the three subcarriers in the middle use 16QAM modulation for data transmission, and the remaining subcarriers transmit DMRS pilots for channel estimation; that is, for multi-subband combined transmission, the 1st, 3rd...M-3, M-1st symbols use the same resource mapping method: all subcarriers use 16QAM modulation for data transmission; the 2nd, 4th...M-2, M symbols use the same resource mapping method: one subcarrier on each side edge is left empty for data or pilot transmission, the three middle subcarriers use 16QAM modulation for data transmission, and the remaining subcarriers are used to transmit DMRS pilots for channel estimation.

[0114] In the fourth mode:

[0115] If a single subband is used for data transmission, then in the single subband, all subcarriers of the odd-numbered symbols use QPSK modulation for data transmission, and there is one subcarrier on each side edge of the even-numbered symbols that does not perform data transmission or pilot transmission, and the remaining subcarriers transmit DMRS pilots for channel estimation. In addition to this example, there is another possible example in which all subcarriers of the even-numbered symbols transmit DMRS pilots for channel estimation; that is, for a single subband, the 1st, 3rd...M-3, M-1 symbols use the same resource mapping method: all subcarriers use QPSK modulation for data transmission; the 2nd, 4th...M-2, M symbols use the same resource mapping method: there is one subcarrier on each side edge of the 2nd, 4th...M-2, M symbols that does not perform data transmission or pilot transmission, and the remaining subcarriers transmit DMRS pilots for channel estimation. Accordingly, in addition to this example, there is another possible example in which all subcarriers are used to transmit DMRS pilots for channel estimation.

[0116] If multi-subband merging is used for data transmission, then in the merged subband, all subcarriers of the odd-numbered symbols use QPSK modulation for data transmission, one subcarrier on each side edge of the even-numbered symbols does not perform data transmission or pilot transmission, the three subcarriers in the middle use QPSK modulation for data transmission, and the remaining subcarriers transmit DMRS pilots for channel estimation; that is, for multi-subband combined transmission, the 1st, 3rd...M-3, M-1st symbols use the same resource mapping method: all subcarriers use QPSK modulation for data transmission; the 2nd, 4th...M-2, M symbols use the same resource mapping method: one subcarrier on each side edge is left empty for data or pilot transmission, the three middle subcarriers use QPSK modulation for data transmission, and the remaining subcarriers are used to transmit DMRS pilots for channel estimation.

[0117] The embodiment of the present invention considers a flexible resource mapping scheme for mixed data transmission of different modulation orders under DMRS configuration for the case of single subband and multi-subband combined transmission, and is more suitable for the design of narrowband F-OFDM system filters. It can be understood that the DMRS configuration mentioned above is only one of the DMRS configuration situations, which is mainly used in scenarios where the channel changes rapidly. For scenarios where the channel changes slowly, the number of DMRS configurations will be reduced at intervals, and more resource blocks for data transmission will be added, thereby achieving a higher transmission rate. For multi-subband combined transmission, that is, when the protection interval between two subbands is 0, multiple subbands can be regarded as one large subband.

[0118] The process of acquiring the time domain filter coefficients of the baseband filter in the above step 102 includes:

[0119] The Kaiser window is used as the truncation window to truncate the impulse response of the linear phase filter to obtain the time domain filter coefficient of the baseband filter. The time domain filter coefficient includes the length of the baseband filter and the shape parameters of the Kaiser window function (also called the control window function).

[0120] For example, the frequency domain response H of the ideal filter given by the system d (e jω ) is transformed into a Sinc function h through IDFT (Inverse Discrete Fourier Transform) d (n), add the window function ω(n) to the infinite-length impulse response to perform a finite-length truncation to obtain an approximation to h d (n) is the time domain unit impulse response h(n) of the FIR filter.

[0121] In view of the problem that the current F-OFDM sub-band filter cannot flexibly adjust the filter parameters according to the communication scenario, the present invention adopts the design of a sub-band filter based on a Kaiser window. By adjusting the two parameters of the filter length N and the parameter β of the Kaiser window function shape, the balance between the main lobe width and the side lobe amplitude can be adjusted, thereby reducing narrowband interference in the communication system.

[0122] The time domain expression of the subband filter using the Kaiser window as the truncation window is:

[0123]

[0124] Where f(n) represents the time domain of the subband filter, n is the nth sampling point, and f d (n) represents an ideal linear phase filter, and I0 represents a modified Bessel function.

[0125] Assume that the subband filter parameters given by the F-OFDM system are: the passband cutoff frequency is f p , the stop band cutoff frequency is f s , the passband ripple is δ p , the stopband attenuation is δ s , the passband ripple amplitude A can be calculated p , and the stopband attenuation A s :

[0126] A p =-20lg(1-δ p )(dB)

[0127] A s =-20lg(δ s )(dB)

[0128] dB stands for decibel, and the shape parameter β can be obtained from the stopband attenuation:

[0129]

[0130] According to the relationship between the filter length and the transition band and stop band attenuation, the length N of the Kaiser window can be obtained:

[0131]

[0132] In this way, all the parameters in the above time domain expression can be obtained, where Δω is a parameter related to the impulse response adding window function ω(n).

[0133] After completing the above filter coefficient design process, in order to further reduce the complexity and calculation amount of the filtered signal under high sampling rate, considering that the time domain filter coefficients on both sides are very small for the overall filter coefficient, the filter time domain filter coefficient can be truncated and the smaller time domain filter coefficient on the side can be discarded, thereby achieving the purpose of reducing the filtering calculation amount. The truncation process of the time domain filter coefficient is as follows: Figure 3 As shown, Figure 3 The circled parts on both sides are discarded parts. For example, the Kaiser window is used as the truncation window to truncate the impulse response of the linear phase filter. After obtaining the time domain filter coefficient of the baseband filter, the time domain filter coefficients on both sides of the time domain filter coefficient of the baseband filter can be intercepted based on the EVM (Error Vector Magnitude) performance requirements of the F-OFDM system; the EVM performance requirements corresponding to different modulation modes are different. When intercepting, it is necessary to consider the EVM performance of the communication system, and discard as many time domain filter coefficients as possible on the basis of meeting the performance requirements of Table 2. EVM performance may be related to the communication scenario and channel conditions.

[0134] Table 2

[0135] Modulation EVM Requirements QPSK 16％ 16QAM 11％ 64QAM 6.5％ 256QAM 2％ 1024QAM (optional) 1% (optional)

[0136] The baseband filter means that the center frequency of the filter is 0, so after the time domain filter coefficients of the baseband filter are generated, the filter coefficients can be frequency-shifted according to the positions of each sub-band in the F-OFDM system. For example, in the above step 102, the time domain filter coefficients of the baseband filter are frequency-shifted according to the frequency domain occupied position of the sub-band, and when the time domain coefficients of the sub-band filter are generated, the center frequency of the sub-band can be calculated according to the frequency domain occupied position of the sub-band, the time domain filter coefficients of the baseband filter and the calculation formula of the center frequency of the sub-band; the time domain coefficients of the sub-band filter are calculated according to the center frequency of the sub-band and the calculation formula of the time domain coefficients of the sub-band.

[0137] Assume that the F-OFDM system has two subbands, and the frequency domain occupied positions of each subband are the first subband and the second subband respectively. The total number of subcarriers in the first subband is M1, and the number of all subcarriers is [K min ,K max ], the number of guard carriers with a frequency interval of the first subband is N1, the total number of subcarriers on the second subband is M2, and the number of guard carriers with a frequency interval of the second subband is N2; for example, the number of all subcarriers can be 2048 subcarriers, K min and K max The value range is an integer in the range of [-1023,1024].

[0138] When the sub-band is the first sub-band, the calculation formula of the sub-band center frequency is as follows:

[0139]

[0140] When the sub-band is the second sub-band, the calculation formula of the center frequency of the sub-band refers to the following formula:

[0141] F2=(K max +N1)*Δf1+(N2+M2 / 2+0.5)*Δf2, where K max +N1 is an even number, F1 is the center frequency of the first sub-band, F2 is the center frequency of the second sub-band, Δf1 and Δf2 are the bandwidths;

[0142] When the sub-band is the first sub-band, the time domain coefficient calculation formula of the sub-band refers to the following formula:

[0143]

[0144] When the sub-band is the first sub-band, the time domain coefficient calculation formula of the sub-band refers to the following formula:

[0145] Where f1(n) is the time domain coefficient of the first subband, f2(n) is the time domain coefficient of the second subband, f(n) is the value of the original signal at the nth sampling point, j is the imaginary unit, and L is the total number of sampling points.

[0146] Correspondingly, when the receiving end performs matched filtering on the received data of the sub-band, the matched filter of the sub-band can be used to perform matched filtering on the received data of the sub-band according to the frequency domain occupancy position of the sub-band, that is, when the receiving end filter is selected, the matched filter of the transmitting end is used to filter the received signal.

[0147] When the sub-band is the first sub-band, the matched filter of the sub-band refers to the following formula:

[0148] g1(n)=f1 * (Ln-1),n∈[0,L-1],

[0149] When the sub-band is the first sub-band, the matched filter refers to the following formula:

[0150] Where g1(n) is the matched filter of the first subband, g2(n) is the matched filter of the second subband, and f1 * is the conjugate of the time domain coefficient of the first subband, is the conjugate of the time domain coefficient of the second subband, n is the value at the nth sampling point, and L is the total number of sampling points.

[0151] The receiving system uses a sub-band matching filter to filter out frequency signals belonging to other sub-bands outside the sub-band, suppress signal interference from other sub-bands, maximize the signal-to-noise ratio of the received signal, and maximize the effectiveness of information transmission in the communication system.

[0152] In order to reduce the complexity of filtering implementation, frequency domain coefficients can be used instead of time domain convolution for filtering operations. For example, in the above step 103, the time domain coefficients of the subband filter are used to perform frequency domain filtering on the mapped subband data. When the subband data is obtained, the mapped data can be segmented to obtain multiple data signal segments; the time domain coefficients of the subband filter are converted into frequency domain coefficients, and each data signal segment is converted into a frequency domain data signal respectively; each frequency domain data signal is frequency-domain multiplied with the corresponding frequency domain coefficient to obtain each filtered frequency domain data signal; each filtered frequency domain data signal is connected to obtain subband data.

[0153] In one implementation, see Figure 4 As shown, segmenting the mapped data to obtain multiple data signal segments includes: performing a 0-filling operation before the mapped data to obtain 0-filled data; dividing the 0-filled data into multiple data segments of length M; starting from the second data segment of length M, adding the last L-1 data signals of the previous data segment before each data segment of length M to obtain multiple data signal segments of length M+L-1. Correspondingly, as Figure 5 As shown, each filtered frequency domain data signal is connected to obtain sub-band data, including: in each filtered frequency domain data signal, starting from the second filtered frequency domain data signal, the L-1 data before each filtered frequency domain data signal are discarded to obtain multiple data segments with a length of M; and multiple data segments with a length of M are connected to obtain sub-band data.

[0154] The filtering process may include the following steps: (1) performing a zero-padding operation on the transmitted data X(n), i.e., adding L-1 zeros before the data segment, and then performing a segmentation operation on the transmitted data, dividing the transmitted data signal into M small data segments, each of which includes the following data: x1(n), x2(n), x3(n)..., x k (n), where the data length of the last data segment can be less than or equal to M. If the data length of the last data segment is less than M, a zero padding operation can be performed after the data segment to make its length reach M (so that the last data segment includes L-1 data signals and data x k (n)), and then add the last L-1 data signals corresponding to the previous data segment to each small data segment, so that each small data signal segment after segmentation becomes a data signal segment with a length of M+L-1. The segmentation process is as follows Figure 4 As shown. (2) The time domain filter coefficients are converted into frequency filter coefficients through FFT transformation. The data signal after the segmentation operation is also converted into the corresponding frequency domain data signal through FFT transformation. Then, each small segment of the frequency domain data signal is multiplied by the corresponding frequency domain filter coefficient to replace the time domain convolution for filtering operation. (3) Each small data signal segment is connected in sequence. Before connection, the first L-1 data in each small segment of data information needs to be discarded. If the length of the last small data segment is less than M, the front is padded with 0, and the corresponding data needs to be discarded when it is discarded. The data merging process is as follows. Figure 5 As shown. Let x i (n) represents the i-th small data segment obtained after the transmitted data signal is segmented. The overall process of the frequency domain filtering operation can be expressed as follows: i (n) = IFFT M+L-1 (FFT M+L-1 {x i [n]}×FFT M+L-1 {h[n]}), y i (n) is the signal after filtering, IFFT M+L-1 is the inverse fast Fourier transform, FFT M+L-1 is the fast Fourier transform, x i [n] are the time domain signal samples and h[n] are the filter coefficients.

[0155] like Figure 6 As shown, the low-complexity narrowband filtering process proposed in the embodiment of the present invention includes the following steps:

[0156] Step 1: Design the time domain coefficients of the baseband filter according to the system subband filter design indicators;

[0157] Step 2: The time domain filter coefficients of the filter designed above are truncated, and the smaller time domain filter coefficients at the side are discarded. On the basis of controlling the EVM limit of the communication system, more filter coefficients are discarded;

[0158] Step 3: Design the time domain filter coefficients of the multiple sub-bands according to the frequency domain occupied positions of the multiple sub-bands;

[0159] Step 4: Convert the above-obtained time domain data and time domain filter coefficients to the frequency domain, and complete the filtering process by multiplying in the frequency domain, thereby further reducing the implementation complexity of the filtering process.

[0160] In the communication system, the design of the transmitter and receiver filters is crucial to the performance of the F-OFDM system, and FIR (Finite Impulse Response) filters are commonly used in communication systems for filtering. The design steps of FIR filters mainly include determining the filter design indicators and design methods. The filter design indicators are determined by the filtering requirements, and the filter design methods mainly include window design method, frequency sampling method, equal ripple design method, etc.

[0161] Taking the window function design method as an example, the general design process of the window function method is: through the systematic analysis of the index parameters of the filter, the frequency response H of the ideal filter is obtained. d (e jω ), but the frequency domain response of the rational filter cannot be realized due to practical factors. Therefore, an FIR filter is designed and its frequency response H(e jω ) approaches H d (e jω ), the most direct method of this approximation is to use the unit impulse response h(n) of the FIR filter in the time domain to approximate the ideal unit impulse response h d (n). In the time domain, the infinite impulse response is cut into finite lengths. As long as the window length is long enough, a reasonable FIR filter can be designed. d (e iw )'s IDTFT derives h d (n)

[0162]

[0163] ω is the normalized angular frequency, due to H d (e jω ) is a rectangular frequency characteristic, so after IDFT h d (n) is infinite in the time domain and is non-causal. However, the FIR filter is finite in length, so a finite h(n) must be used to approximate the infinite h d(n), the simplest method is to intercept the most important part of h(n) and convert the infinite length h d (n) is truncated to a finite length sequence of length N, which is equivalent to h d A rectangular window of length N is applied to (n). More generally, a window function ω(n) of length N can be used to intercept h d (n), i.e.

[0164] h(n)=ω(n)*h d (n)

[0165] For F-OFDM systems, it is also critical to reduce the implementation complexity of the filtering process. The computational complexity of the FIR filter is mainly affected by the following factors:

[0166] ① The order of the filter: The higher the order, the higher the computational complexity.

[0167] ② Sampling rate: The higher the sampling rate, the higher the computational complexity.

[0168] ③ Transition bandwidth and cutoff frequency: The stricter the frequency response requirements, the higher the calculation complexity.

[0169] The quantification of computational complexity can be evaluated by the number of multipliers or the number of adders (or accumulators). In FIR filter design, the technology of reducing computational complexity has an important impact on filter performance and practical application. When evaluating common technologies for reducing computational complexity, it is mainly necessary to consider the accuracy evaluation of the algorithm, the comparative analysis of computational complexity, and the performance of different technologies in practical applications.

[0170] Existing research on F-OFDM system filter design is based on broadband F-OFDM systems in the public network frequency band, and research on narrowband F-OFDM system filter design is still very lacking.

[0171] The present invention proposes a low-complexity filtering method suitable for narrowband F-OFDM systems. The filtering design scheme can reduce the complexity of filtering implementation while adapting to different discrete spectrum requirements. The flexible resource mapping scheme proposed on this basis can maximize the effectiveness of information transmission in the communication system. The invention makes up for the shortcomings of existing research on narrowband F-OFDM system filters, making it possible to effectively utilize discrete narrowband spectrum resources. Specifically, through the reasonable design of subband filter coefficients and frequency domain filtering, the implementation complexity of the filtering process is effectively reduced; and based on the characteristic that the subband filter of the narrowband F-OFDM system has a large interference on the available subband edge subcarrier data transmission, a flexible resource mapping method combining multiple modulation methods is designed, thereby reducing the complexity of filtering implementation and the impact of filtering on data transmission performance. The filtering process is designed by means of window function design method, filter coefficient truncation, etc., and under the premise of ensuring the reliability of the communication system, the out-of-band leakage of the filtered signal of the narrowband F-OFDM system is effectively reduced, and the problem of large filtering complexity caused by high sampling rate is solved.

[0172] In the embodiment of the present invention, a low-complexity filtering implementation scheme is proposed to address the problem of strictly controlling out-of-band power and reducing implementation complexity in the case of multiple sub-bands in a narrowband F-OFDM system. In order to reduce the impact of the narrowband F-OFDM system filter on data transmission, a resource allocation scheme corresponding to different modulation modes is proposed to ensure the reliability of information transmitted by the communication system. The present invention combines narrowband filtering implementation with resource mapping schemes, while improving the utilization of time-frequency resources, ensuring the reliability and effectiveness of data transmission in the communication system, and has a relatively superior performance in communication system performance.

[0173] Embodiment 2:

[0174] Based on the same inventive concept, the present invention also provides a communication system, the structural diagram of which is shown in FIG. Figure 7 As shown, it includes: a transmitting end and a receiving end; the transmitting end is used to implement the filtering implementation method based on orthogonal frequency division multiplexing of the above embodiment, and the receiving end is used to implement the filtering implementation method based on orthogonal frequency division multiplexing of the above embodiment.

[0175] Embodiment 3:

[0176] Based on the same inventive concept, the present invention also provides a communication device, the structural diagram of which is shown in FIG. Figure 8 As shown, it includes: a communication module and a processing module.

[0177] In one implementation, the communication device is applied to a transmitting end, wherein:

[0178] The processing module is used to obtain data to be transmitted, where the data corresponds to data of multiple sub-bands; based on each sub-band, according to the modulation mode and resource mapping mode corresponding to the transmission rate of the F-OFDM system, resource mapping is performed on the data of the sub-band to obtain the mapped data; according to the frequency domain occupied position of the sub-band, the time domain filter coefficient of the baseband filter is frequency shifted to generate the time domain coefficient of the sub-band filter; the time domain coefficient of the sub-band filter is used to perform frequency domain filtering on the mapped sub-band data to obtain the sub-band data;

[0179] The communication module is used to send sub-band data of each sub-band.

[0180] In a possible implementation manner, the processing module is further configured to:

[0181] Calculate the modulation mode according to the transmission rate, symbol transmission rate and channel coding rate required by the F-OFDM system. The modulation modes include 256QAM, 64QAM, 16QAM and QPSK.

[0182] When the modulation mode is 256QAM, determining the resource mapping mode to be the first mode;

[0183] When the modulation mode is 64QAM, determining the resource mapping mode to be the second mode;

[0184] When the modulation mode is 16QAM, determining the resource mapping mode to be the third mode;

[0185] When the modulation mode is QPSK, determining the resource mapping mode to be the fourth mode;

[0186] The first mode, the second mode, the third mode and the fourth mode correspond to different DMRS configurations respectively.

[0187] In a possible implementation, in the first mode: if a single subband is used for data transmission, then in the single subband, one subcarrier on each side edge of the odd-numbered symbol does not perform data transmission or pilot transmission, one carrier on the secondary edge uses 64QAM modulation for data transmission, and the remaining subcarriers use 256QAM modulation for data transmission, and two subcarriers on each side edge of the even-numbered symbol do not perform data transmission or pilot transmission, and the remaining subcarriers transmit DMRS pilots for channel estimation; if multiple subbands are combined for data transmission, then in the combined subband, two subcarriers on each side edge of the odd-numbered symbol use 64QAM modulation for data transmission, and the remaining subcarriers use 256QAM modulation for data transmission, one subcarrier on each side edge of the even-numbered symbol does not perform data transmission or pilot transmission, the three subcarriers located in the middle use 256QAM modulation for data transmission, and the remaining subcarriers transmit DMRS pilots for channel estimation;

[0188] In the second mode: if a single subband is used for data transmission, then in the single subband, one subcarrier on each side edge of the odd-numbered symbol uses 16QAM modulation for data transmission, and the remaining subcarriers use 64QAM modulation for data transmission, one subcarrier on each side edge of the even-numbered symbol does not perform data transmission or pilot transmission, and the remaining subcarriers transmit DMRS pilots for channel estimation; if multiple subbands are combined for data transmission, then in the combined subband, one subcarrier on each side edge of the odd-numbered symbol uses 16QAM modulation for data transmission, and the remaining subcarriers use 64QAM modulation for data transmission, one subcarrier on each side edge of the even-numbered symbol does not perform data transmission or pilot transmission, the three subcarriers located in the middle use 64QAM modulation for data transmission, and the remaining subcarriers transmit DMRS pilots for channel estimation;

[0189] In the third mode: if a single subband is used for data transmission, then in the single subband, all subcarriers of the odd-numbered symbols use 16QAM modulation for data transmission, and one subcarrier on each side edge of the even-numbered symbols does not perform data transmission or pilot transmission, and the remaining subcarriers transmit DMRS pilots for channel estimation; if multiple subbands are combined for data transmission, then in the combined subband, all subcarriers of the odd-numbered symbols use 16QAM modulation for data transmission; one subcarrier on each side edge of the even-numbered symbols does not perform data transmission or pilot transmission, and the three subcarriers located in the middle use 16QAM modulation for data transmission, and the remaining subcarriers transmit DMRS pilots for channel estimation;

[0190] In the fourth mode: if a single subband is used for data transmission, then in the single subband, all subcarriers of the odd-numbered symbols use QPSK modulation for data transmission, and there is one subcarrier on each side edge of the even-numbered symbols without data transmission or pilot transmission, and the remaining subcarriers transmit DMRS pilots for channel estimation; if multiple subbands are merged for data transmission, then in the merged subband, all subcarriers of the odd-numbered symbols use QPSK modulation for data transmission, and there is one subcarrier on each side edge of the even-numbered symbols without data transmission or pilot transmission, the three subcarriers located in the middle use QPSK modulation for data transmission, and the remaining subcarriers transmit DMRS pilots for channel estimation.

[0191] In a possible implementation manner, the processing module is further configured to:

[0192] The Kaiser window is used as a truncation window to truncate the impulse response of the linear phase filter to obtain the time domain filter coefficient of the baseband filter. The time domain filter coefficient includes the length of the baseband filter and the shape parameter of the Kaiser window function.

[0193] In a possible implementation manner, the processing module is further configured to:

[0194] Based on the error vector magnitude (EVM) performance requirement of the F-OFDM system, the time domain filter coefficients on both sides of the time domain filter coefficients of the baseband filter are intercepted;

[0195] Different modulation modes have different EVM performance requirements.

[0196] In a possible implementation manner, the processing module is specifically configured to:

[0197] Calculate the center frequency of the sub-band according to the frequency domain occupied position of the sub-band, the time domain filter coefficient of the baseband filter and the calculation formula of the center frequency of the sub-band;

[0198] The time domain coefficients of the subband filter are calculated according to the center frequency of the subband and the time domain coefficient calculation formula of the subband.

[0199] In a possible implementation manner, it is assumed that the frequency domain occupied positions of each subband are the first subband and the second subband, the total number of subcarriers on the first subband is M1, and the number of all subcarriers is [K min ,K max ], the number of guard carriers with a frequency interval of the first subband is N1, the total number of subcarriers on the second subband is M2, and the number of guard carriers with a frequency interval of the second subband is N2; when the subband is the first subband, the calculation formula for the center frequency of the subband is as follows:

[0200]

[0201] When the sub-band is the second sub-band, the calculation formula of the sub-band center frequency refers to the following formula:

[0202] F2=(K max +N1)*Δf1+(N2+M2 / 2+0.5)*Δf2, where K max +N1 is an even number, F1 is the center frequency of the first sub-band, F2 is the center frequency of the second sub-band, Δf1 and Δf2 are the bandwidths;

[0203] When the sub-band is the first sub-band, the calculation formula of the sub-band time domain coefficient is as follows:

[0204]

[0205] When the sub-band is the first sub-band, the calculation formula of the sub-band time domain coefficient is as follows:

[0206] Where f1(n) is the time domain coefficient of the first subband, f2(n) is the time domain coefficient of the second subband, f(n) is the value of the original signal at the nth sampling point, j is the imaginary unit, and L is the total number of sampling points.

[0207] In a possible implementation manner, the processing module is specifically configured to:

[0208] Segmenting the mapped data to obtain multiple data signal segments;

[0209] Converting the time domain coefficients of the subband filter into frequency domain coefficients, and converting each data signal segment into a frequency domain data signal respectively;

[0210] Multiply each frequency domain data signal by the corresponding frequency domain coefficient in the frequency domain to obtain each filtered frequency domain data signal;

[0211] Each filtered frequency domain data signal is connected to obtain sub-band data.

[0212] In a possible implementation manner, the processing module is specifically configured to:

[0213] Perform a 0-filling operation before the mapped data to obtain the 0-filled data;

[0214] Divide the data after the zero padding into multiple data segments of length M;

[0215] Starting from the second data segment with a length of M, the last L-1 data signals of the previous data segment are added before each data segment with a length of M to obtain multiple data signal segments with a length of M+L-1.

[0216] In a possible implementation manner, the processing module is specifically configured to:

[0217] In each filtered frequency domain data signal, starting from the second filtered frequency domain data signal, L-1 data before each filtered frequency domain data signal are discarded to obtain a plurality of data segments with a length of M;

[0218] Connect multiple data segments of length M to obtain sub-band data.

[0219] In one implementation, the communication device is applied to a receiving end, wherein:

[0220] A communication device for acquiring received data; the data corresponds to received data of a plurality of sub-bands;

[0221] A processing device, for performing matched filtering and demapping processing on the received data of the sub-band based on each sub-band to obtain original data;

[0222] The received data is obtained by performing resource mapping on the sub-band data based on each sub-band by the transmitter according to the modulation mode and resource mapping mode corresponding to the transmission rate of the F-OFDM system, and obtaining the mapped data; performing frequency shift on the time domain filter coefficient of the baseband filter according to the frequency domain occupied position of the sub-band to generate the time domain coefficient of the sub-band filter; using the time domain coefficient of the sub-band filter, performing frequency domain filtering on the mapped sub-band data, and obtaining the sub-band data before sending.

[0223] In a possible implementation manner, the processing module is specifically configured to:

[0224] According to the frequency domain occupied position of the sub-band, the matched filter of the sub-band is used to perform matched filtering processing on the received data of the sub-band;

[0225] When the sub-band is the first sub-band, the matched filter of the sub-band refers to the following formula:

[0226] g1(n)=f1 * (Ln-1),n∈[0,L-1],

[0227] When the subband is the first subband, the matched filter refers to the following formula:

[0228] Where g1(n) is the matched filter of the first subband, g2(n) is the matched filter of the second subband, and f1 * is the conjugate of the time domain coefficient of the first subband, is the conjugate of the time domain coefficient of the second subband, n is the value at the nth sampling point, and L is the total number of sampling points.

[0229] Embodiment 4:

[0230] like Fig. 9 As shown, the present invention also provides an electronic device, which may be a computer device, a single-chip device, an intelligent mobile device, etc. The electronic device in this embodiment may include a processor, a memory, a transceiver component, etc. The memory, the processor, and the transceiver component are connected via a bus; the memory may be used to store an execution program, and an exemplary execution program may include instructions; the processor is used to execute the instructions stored in the memory. The memory may also be used to store data, which may be called and / or modified when the instructions are executed.

[0231] The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, which is suitable for implementing one or more instructions, and is specifically suitable for loading and executing one or more instructions in a storage medium to implement a corresponding method flow or a corresponding function, so as to implement the steps of a filtering implementation method based on orthogonal frequency division multiplexing in the above embodiment. Embodiment 5:

[0232] Based on the same inventive concept, the present invention also provides a readable storage medium, specifically an electronic device readable storage medium (Memory), which is a memory device in an electronic device for storing programs and data. It can be understood that the storage medium here can include both built-in storage media in electronic devices and, of course, extended storage media supported by electronic devices. The storage medium provides a storage space, which stores the operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by a processor are also stored in the storage space, and these instructions can be one or more execution programs (including program codes). It should be noted that the storage medium here can be a high-speed RAM memory or a non-volatile memory, such as at least one disk memory. The processor loads and executes one or more instructions stored in the storage medium, which can implement the steps of a filtering implementation method based on orthogonal frequency division multiplexing in the above embodiment.

[0233] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0234] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0235] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0236] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0237] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit its protection scope. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that after reading the present invention, those skilled in the art can still make various changes, modifications or equivalent substitutions to the specific implementation methods of the application, but these changes, modifications or equivalent substitutions are all within the protection scope of the claims to be approved.

Claims

1. A filtering implementation method based on orthogonal frequency division multiplexing, characterized in that: include: Acquire data to be transmitted, the data corresponding to data of multiple sub-bands; Based on each sub-band, according to the modulation mode and resource mapping mode corresponding to the transmission rate of the orthogonal frequency division multiplexing filtering F-OFDM system, resource mapping is performed on the data of the sub-band to obtain mapped data; according to the frequency domain occupied position of the sub-band, the time domain filter coefficient of the baseband filter is frequency shifted to generate the time domain coefficient of the sub-band filter; using the time domain coefficient of the sub-band filter, frequency domain filtering is performed on the mapped sub-band data to obtain sub-band data; Subband data for each subband is sent.

2. The method according to claim 1, characterized in that The process of determining the modulation mode and resource mapping mode corresponding to the transmission rate of the F-OFDM system includes: Calculate the modulation mode according to the transmission rate, symbol transmission rate and channel coding rate required by the F-OFDM system, wherein the modulation mode includes 256 quadrature amplitude modulation QAM, 64QAM, 16QAM and quadrature phase shift keying QPSK; When the modulation mode is 256QAM, determining the resource mapping mode to be the first mode; When the modulation mode is 64QAM, determining the resource mapping mode to be the second mode; When the modulation mode is 16QAM, determining the resource mapping mode to be the third mode; When the modulation mode is QPSK, determining the resource mapping mode to be the fourth mode; The first mode, the second mode, the third mode and the fourth mode correspond to different DMRS configurations respectively.

3. The method according to claim 2, characterized in that In the first mode: if a single subband is used for data transmission, then in the single subband, there is one subcarrier on each side edge of the odd-numbered symbol for no data transmission or pilot transmission, one carrier on the secondary edge uses 64QAM modulation for data transmission, and the remaining subcarriers use 256QAM modulation for data transmission, and two subcarriers on each side edge of the even-numbered symbol for no data transmission or pilot transmission, and the remaining subcarriers transmit DMRS pilots for channel estimation; if multiple subbands are merged for data transmission, then in the merged subband, two subcarriers on each side edge of the odd-numbered symbol use 64QAM modulation for data transmission, and the remaining subcarriers use 256QAM modulation for data transmission, one subcarrier on each side edge of the even-numbered symbol for no data transmission or pilot transmission, the three subcarriers located in the middle use 256QAM modulation for data transmission, and the remaining subcarriers transmit DMRS pilots for channel estimation; In the second mode: if a single subband is used for data transmission, then in the single subband, one subcarrier on each side edge of the odd-numbered symbol uses 16QAM modulation for data transmission, and the remaining subcarriers use 64QAM modulation for data transmission, and one subcarrier on each side edge of the even-numbered symbol does not perform data transmission or pilot transmission, and the remaining subcarriers transmit DMRS pilots for channel estimation; if multiple subbands are merged for data transmission, then in the merged subband, one subcarrier on each side edge of the odd-numbered symbol uses 16QAM modulation for data transmission, and the remaining subcarriers use 64QAM modulation for data transmission, one subcarrier on each side edge of the even-numbered symbol does not perform data transmission or pilot transmission, the three subcarriers located in the middle use 64QAM modulation for data transmission, and the remaining subcarriers transmit DMRS pilots for channel estimation; In the third mode: if a single subband is used for data transmission, then in the single subband, all subcarriers of the odd-numbered symbols use 16QAM modulation for data transmission, and one subcarrier on each side edge of the even-numbered symbol does not perform data transmission or pilot transmission, and the remaining subcarriers transmit DMRS pilots for channel estimation; if multiple subbands are combined for data transmission, then in the combined subband, all subcarriers of the odd-numbered symbols use 16QAM modulation for data transmission; one subcarrier on each side edge of the even-numbered symbol does not perform data transmission or pilot transmission, and the three subcarriers located in the middle use 16QAM modulation for data transmission, and the remaining subcarriers transmit DMRS pilots for channel estimation; In the fourth mode: if a single subband is used for data transmission, then in the single subband, all subcarriers of the odd-numbered symbols use QPSK modulation for data transmission, and there is one subcarrier on each side edge of the even-numbered symbols without data transmission or pilot transmission, and the remaining subcarriers transmit DMRS pilots for channel estimation; if multiple subbands are merged for data transmission, then in the merged subband, all subcarriers of the odd-numbered symbols use QPSK modulation for data transmission, and there is one subcarrier on each side edge of the even-numbered symbols without data transmission or pilot transmission, the three subcarriers located in the middle use QPSK modulation for data transmission, and the remaining subcarriers transmit DMRS pilots for channel estimation.

4. The method according to any one of claims 1 to 3, characterized in that: The process of acquiring the time domain filter coefficients of the baseband filter includes: The Kaiser window is used as a truncation window to truncate the impulse response of the linear phase filter to obtain the time domain filter coefficient of the baseband filter. The time domain filter coefficient includes the length of the baseband filter and the shape parameter of the Kaiser window function.

5. The method according to claim 4, characterized in that After the Kaiser window is used as the truncation window to truncate the impulse response of the linear phase filter to obtain the time domain filter coefficient of the baseband filter, the method further includes: Based on the error vector magnitude (EVM) performance requirement of the F-OFDM system, the time domain filter coefficients on both sides of the time domain filter coefficients of the baseband filter are intercepted; Different modulation modes have different EVM performance requirements.

6. The method according to claim 5, characterized in that The step of frequency-shifting the time-domain filter coefficients of the baseband filter according to the frequency-domain occupied position of the subband to generate the time-domain coefficients of the subband filter comprises: Calculate the center frequency of the sub-band according to the frequency domain occupied position of the sub-band, the time domain filter coefficient of the baseband filter and the center frequency calculation formula of the sub-band; The time domain coefficient of the sub-band filter is calculated according to the center frequency of the sub-band and the time domain coefficient calculation formula of the sub-band.

7. The method according to claim 6, characterized in that Assume that the frequency domain occupied positions of each subband are the first subband and the second subband respectively, the total number of subcarriers on the first subband is M1, and the number of all subcarriers is [K min ,K max ], the number of protection carriers with a frequency interval of the first subband being the spacing is N1, the total number of subcarriers on the second subband is M2, and the number of protection carriers with a frequency interval of the second subband being the spacing is N2; when the subband is the first subband, the calculation formula for the center frequency of the subband is as follows: When the sub-band is the second sub-band, the calculation formula of the center frequency of the sub-band refers to the following formula: F2=(K max +N1)*Δf1+(N2+M2 / 2+0.5)*Δf2, where K max +N1 is an even number, F1 is the center frequency of the first sub-band, F2 is the center frequency of the second sub-band, Δf1 and Δf2 are the bandwidths; When the sub-band is the first sub-band, the time domain coefficient calculation formula of the sub-band refers to the following formula: When the sub-band is the first sub-band, the time domain coefficient calculation formula of the sub-band refers to the following formula: Where f1(n) is the time domain coefficient of the first subband, f2(n) is the time domain coefficient of the second subband, f(n) is the value of the original signal at the nth sampling point, j is the imaginary unit, and L is the total number of sampling points.

8. The method according to claim 1, characterized in that The using the time domain coefficient of the sub-band filter to perform frequency domain filtering on the mapped sub-band data to obtain the sub-band data includes: Segmenting the mapped data to obtain a plurality of data signal segments; Converting the time domain coefficients of the subband filter into frequency domain coefficients, and converting each of the data signal segments into a frequency domain data signal; Multiply each frequency domain data signal by the corresponding frequency domain coefficient in the frequency domain to obtain each filtered frequency domain data signal; Each filtered frequency domain data signal is connected to obtain sub-band data.

9. The method according to claim 8, characterized in that The segmenting the mapped data to obtain a plurality of data signal segments comprises: Performing a 0-padding operation before the mapped data to obtain 0-padding data; Divide the data padded with 0 into a plurality of data segments of length M; Starting from the second data segment with a length of M, the last L-1 data signals of the previous data segment are added before each data segment with a length of M to obtain multiple data signal segments with a length of M+L-1.

10. The method according to claim 9, characterized in that The step of connecting each filtered frequency domain data signal to obtain sub-band data comprises: In each of the filtered frequency domain data signals, starting from the second filtered frequency domain data signal, discard L-1 data before each filtered frequency domain data signal to obtain a plurality of data segments with a length of M; The multiple data segments with a length of M are connected to obtain sub-band data.

11. A communication device, characterized in that: include: A processing module, used for acquiring data to be transmitted, wherein the data corresponds to data of multiple sub-bands; Based on each sub-band, according to the modulation mode and resource mapping mode corresponding to the transmission rate of the orthogonal frequency division multiplexing filtering F-OFDM system, resource mapping is performed on the data of the sub-band to obtain mapped data; according to the frequency domain occupied position of the sub-band, the time domain filter coefficient of the baseband filter is frequency shifted to generate the time domain coefficient of the sub-band filter; using the time domain coefficient of the sub-band filter, frequency domain filtering is performed on the mapped sub-band data to obtain sub-band data; The communication module is used to send sub-band data of each sub-band.

12. A filtering implementation method based on orthogonal frequency division multiplexing, characterized in that: include: Get the received data; The data corresponds to received data of multiple sub-bands; Based on each sub-band, performing matched filtering and demapping processing on the received data of the sub-band to obtain original data; The received data is obtained by performing resource mapping on the data of the subband based on each subband by the transmitter according to the modulation mode and resource mapping mode corresponding to the transmission rate of the orthogonal frequency division multiplexing filtering F-OFDM system, and obtaining the mapped data; performing frequency shifting on the time domain filter coefficient of the baseband filter according to the frequency domain occupied position of the subband to generate the time domain coefficient of the subband filter; and performing frequency domain filtering on the mapped subband data using the time domain coefficient of the subband filter to obtain the subband data and then sending it.

13. The method according to claim 12, characterized in that The performing matched filtering on the received data of the sub-band comprises: According to the frequency domain occupied position of the sub-band, using the matched filter of the sub-band to perform matched filtering processing on the received data of the sub-band; When the sub-band is the first sub-band, the matched filter of the sub-band refers to the following formula: g1(n)=f1 * (Ln-1),n∈[0,L-1], When the sub-band is the first sub-band, the matched filter refers to the following formula: Where g1(n) is the matched filter of the first subband, g2(n) is the matched filter of the second subband, and f1 * is the conjugate of the time domain coefficient of the first subband, is the conjugate of the time domain coefficient of the second subband, n is the value at the nth sampling point, and L is the total number of sampling points.

14. A communication device, characterized in that: include: A communication device, configured to obtain received data; the data corresponding to received data of a plurality of sub-bands; A processing device, configured to perform matched filtering and demapping processing on the received data of each sub-band to obtain original data; The received data is obtained by performing resource mapping on the data of the subband based on each subband by the transmitter according to the modulation mode and resource mapping mode corresponding to the transmission rate of the orthogonal frequency division multiplexing filtering F-OFDM system, and obtaining the mapped data; performing frequency shifting on the time domain filter coefficient of the baseband filter according to the frequency domain occupied position of the subband to generate the time domain coefficient of the subband filter; and performing frequency domain filtering on the mapped subband data using the time domain coefficient of the subband filter to obtain the subband data and then sending it.

15. A communication system, characterized in that: It includes a transmitting end and a receiving end; the transmitting end is used to implement the filtering implementation method based on orthogonal frequency division multiplexing as described in any one of claims 1-10 above, and the receiving end is used to implement the filtering implementation method based on orthogonal frequency division multiplexing as described in any one of claims 12-13 above.

16. An electronic device, characterized in that: include: at least one processor and memory; The memory and the processor are connected via a bus; The memory is used to store one or more programs; When the one or more programs are executed by the at least one processor, the filtering implementation method based on orthogonal frequency division multiplexing described in any one of claims 1-10 is implemented, and the terminal is used to implement the filtering implementation method based on orthogonal frequency division multiplexing described in any one of claims 12-13.

17. A readable storage medium, characterized in that: An execution program is stored thereon to implement the filtering implementation method based on orthogonal frequency division multiplexing as described in any one of claims 1-10 above, and the terminal is used to implement the filtering implementation method based on orthogonal frequency division multiplexing as described in any one of claims 12-13 above.

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