CN108234374B

CN108234374B - Uplink multi-carrier transmitting device, system and method

Info

Publication number: CN108234374B
Application number: CN201611154301.5A
Authority: CN
Inventors: 何轲
Original assignee: Leadcore Technology Co Ltd; Datang Semiconductor Design Co Ltd
Current assignee: Leadcore Technology Co Ltd; Datang Semiconductor Design Co Ltd
Priority date: 2016-12-14
Filing date: 2016-12-14
Publication date: 2020-09-25
Anticipated expiration: 2036-12-14
Also published as: CN108234374A

Abstract

The invention provides an uplink multi-carrier transmitting device, a system and a method, which are suitable for a multi-carrier signal format of an NB-IoT protocol, meet the frame structure and the OFDM symbol duration specified by the protocol, simultaneously perform interpolation of corresponding multiple and increase corresponding control logic on the IFFT operation result through IFFT operation with lower point number and different clock domains, thereby replacing the IFFT calculation amount of 128 points in the traditional method, greatly reducing the design complexity of a terminal chip, reducing the realization area, power consumption and cost, and further meeting the design requirements of low cost and low power consumption of the NB-IoT. In addition, the receiving end of the transmitted signal can adopt the traditional method to receive and demodulate, and does not need to make any adjustment and change, thereby reducing the calculation degree and ensuring better applicability and compatibility.

Description

Uplink multi-carrier transmitting device, system and method

Technical Field

The present invention relates to the field of wireless communication technologies, and in particular, to an uplink multi-carrier transmitting apparatus, system, and method.

Background

The cellular-based narrowband Internet of Things (NB-IoT) protocol is the latest narrowband Internet of Things protocol specifically for the Internet of Things recently proposed by the 3GPP (third generation partnership project) standardization organization. The protocol is based on a mature GSM network, a UMTS network or an LTE network, and on the basis, the protocol layer and the physical layer are greatly cut in function and performance aiming at the communication characteristics of the physical network, so that the NB-IoT terminal can better realize the aims of wide coverage, low power consumption, low cost, large connection and the like.

For an uplink multi-carrier transmission mode of a narrowband internet of things protocol, in order to ensure that a symbol length and a frame structure of an OFDM (orthogonal frequency Division Multiplexing) meet NB-IoT protocol specifications, and simultaneously considering design requirements of the NB-IoT protocol on low power consumption and low complexity, current baseband processing generally uses 1.92MHz to sample each subcarrier, and needs to be subjected to 128-point IFFT (Inverse Fast fourier transform) operation. Since the NB-IoT protocol specifies that the occupied bandwidth is 180kHz, and the number of available subcarriers is at most 12, performing 128-point IFFT operation causes a large waste of computing resources, and increases the chip implementation area, power consumption, and cost of the NB-IoT protocol uplink.

Disclosure of Invention

The invention aims to provide an uplink multi-carrier transmitting device and method, aiming at the transmitting format of a narrowband Internet of things protocol uplink multi-carrier, the narrowband Internet of things protocol is satisfied, and meanwhile, the calculation complexity is reduced as much as possible, so that the resource area, the power consumption and the cost required by a terminal chip are reduced.

In order to achieve the above object, the present invention provides an uplink multicarrier transmitting apparatus, comprising:

a Q point IFFT module, which is used for carrying out Q point IFFT operation processing on the sampling signal, wherein Q is the power of 2 and is less than 128;

the R-time-domain up-sampling module is used for performing R-time-domain up-sampling processing on the signal output by the Q-point IFFT module, and the product of R and Q is equal to 128;

a cyclic prefix adding module, configured to add a cyclic prefix to the signal output by the R-fold time-domain upsampling module;

the frequency offset adjusting module is used for carrying out frequency offset processing on the signal output by the cyclic prefix adding module;

and the beam forming filter is used for filtering and waveform adjusting the signals output by the frequency offset adjusting module so as to form transmitting signals.

Further, the uplink multi-carrier transmitting apparatus further includes a sampling module, configured to sample a baseband signal according to one R times of a frequency of a signal output by the time domain up-sampling module, so as to form the sampling signal.

Further, the frequency of the signal output by the R-time domain up-sampling module is 1.92MHz, when Q is 4, the frequency of the sampling signal is 60kHz, and R is 32; when Q is 8, the frequency of the sampling signal is 120kHz, and R is 16; when the Q is 16, the frequency of the sampling signal is 240kHz, and R is 8; when the Q is 32, the frequency of the sampling signal is 480kHz, and R is 4; when Q is 64, the frequency of the sampling signal is 960kHz, and R is 2.

Further, the cyclic prefix adding module adds 10 or 9 pieces of length data to the signal output by the R-time domain up-sampling module as the cyclic prefix, so as to satisfy the specification of the narrowband internet of things protocol on OFDM symbols and frame lengths.

Further, when the original OFDM symbol length of the signal output by the R-fold time-domain up-sampling module is 0, the cyclic prefix adding module adds 10 pieces of length data to the signal output by the R-fold time-domain up-sampling module as the cyclic prefix; and when the original OFDM symbol length of the signal output by the R-time domain up-sampling module is 1-6, the cyclic prefix adding module adds 9 length data to the signal output by the R-time domain up-sampling module to serve as the cyclic prefix.

Further, the frequency offset adjusting module performs frequency offset processing of 1/2 subcarrier on the signal output by the cyclic prefix adding module.

The present invention also provides a multicarrier communication system comprising: the uplink multi-carrier transmitting device and the receiving device for receiving the transmitting signal of the uplink multi-carrier transmitting device are provided.

Further, the receiving apparatus includes:

the timing adjusting module is used for searching frame headers of the received transmitting signals and performing timing processing;

a cyclic prefix removing module, configured to remove a cyclic prefix from the signal output by the timing adjusting module;

and the 128-point FFT module is used for carrying out 128-point FFT on the signal output by the cyclic prefix removing module so as to obtain channel data or a reference signal.

The invention also provides an uplink multi-carrier transmission method, which comprises the following steps:

performing Q-point IFFT operation processing on the sampling signal, wherein Q is a power of 2 and is less than 128;

performing R-time domain up-sampling processing on the signal subjected to the Q-point IFFT operation processing, wherein the product of R and Q is equal to 128;

adding a cyclic prefix to the signal subjected to the R-time domain up-sampling processing;

carrying out frequency offset processing on the signal added with the cyclic prefix;

and filtering and waveform adjusting the signals after the frequency offset processing to form transmitting signals.

Further, the baseband signal is sampled according to the frequency which is one R times of the frequency of the output signal after the time domain up-sampling processing, so as to form the sampling signal.

Further, the frequency of the signal after the time domain up-sampling process of the R times is 1.92MHz, when Q is 4, the frequency of the sampling signal is 60kHz, and R is 32; when Q is 8, the frequency of the sampling signal is 120kHz, and R is 16; when the Q is 16, the frequency of the sampling signal is 240kHz, and R is 8; when the Q is 32, the frequency of the sampling signal is 480kHz, and R is 4; when Q is 64, the frequency of the sampling signal is 960kHz, and R is 2.

Furthermore, 10 or 9 pieces of length data are added to the signal subjected to the R-time domain up-sampling processing as the cyclic prefix, so as to meet the requirements of the narrowband internet of things protocol on OFDM symbols and frame lengths.

Further, when the original OFDM symbol length of the signal subjected to the time domain up-sampling processing of R times is 0, adding 10 length data to the signal subjected to the time domain up-sampling processing of R times as the cyclic prefix; and when the original OFDM symbol length of the signal subjected to the R-time domain up-sampling processing is 1-6, adding 9 length data to the signal subjected to the R-time domain up-sampling processing to be used as the cyclic prefix.

Further, the frequency offset processing of 1/2 subcarrier is carried out on the signal added with the cyclic prefix.

The invention also provides a multi-carrier communication method, which adopts the uplink multi-carrier transmitting device to generate a transmitting signal to send outwards, or generates the transmitting signal to send outwards through the uplink multi-carrier transmitting method.

Further, the multicarrier communication method further comprises the steps of:

receiving the transmitting signal, searching a frame header of the transmitting signal and performing timing processing;

removing the cyclic prefix in the timed signal;

and performing 128-point FFT (fast Fourier transform) on the signal with the cyclic prefix removed to obtain channel data or a reference signal.

Compared with the prior art, the technical scheme of the invention has the following beneficial effects:

1. according to the technical scheme, interpolation is added and lower-point IFFT operation is used during terminal uplink baseband processing, 128-point IFFT operation in the traditional method is replaced, the number and storage space of multipliers are reduced, and the calculation complexity is reduced, so that the area, power consumption and cost required by chip uplink design are reduced, and the requirements of NB-IoT equipment on low power consumption and low cost are better met.

2. When the technical scheme of the invention is used for multi-carrier communication, only the transmitting end can be improved, and the receiving end can continue to adopt the traditional method for receiving and demodulating without any adjustment and change, thereby reducing the calculation degree and ensuring better applicability and compatibility.

Drawings

Fig. 1 is a schematic diagram of a conventional approach NB-IoT terminal uplink multicarrier transmitter portion architecture;

fig. 2 is a schematic diagram of a conventional method NB-IoT base station receiver portion structure;

fig. 3 is a schematic structural diagram of an uplink multi-carrier transmitting apparatus according to an embodiment of the present invention;

fig. 4 shows 12 random data used by the uplink multi-carrier transmitting apparatus according to the embodiment of the present invention;

FIG. 5 is the data of FIG. 4 after a resource mapping process;

FIG. 6 is a graph of the magnitude of the data of FIG. 5 after being subjected to a 16-point IFFT operation;

FIG. 7 is a graph of the amplitude of the data of FIG. 6 after 8 times time domain upsampling;

FIG. 8 is a graph of the magnitude of the data of FIG. 7 after a 128-point FFT;

FIG. 9 is a plot of the magnitude of the data of FIG. 8 after nulling and reordering;

fig. 10 is a schematic diagram of the structure of a multi-carrier communication system of the present invention;

fig. 11 is a flowchart of an uplink multi-carrier transmission method according to an embodiment of the present invention;

fig. 12 is a flowchart of a multicarrier communication method according to an embodiment of the invention.

Detailed Description

According to the 3GPP protocol specification, there are two format definitions for NB-IoT uplinks: 1. single-carrier form (Single-tone form) with subcarrier spacing of both 3.75kHz and 15kHz, 2. Multi-carrier form (Multi-tone form), typically OFDM format, with subcarrier spacing of 15kHz, with a configurable number of subcarriers of 3, 6, 12 cases. While NB-IoT downlink has only one format with a subcarrier spacing of 15 kHz. The NB-IoT system bandwidth is 180kHz, i.e., there are a maximum of 12 subcarriers. The protocol defines the uplink multicarrier form and the downlink cyclic prefix length as shown in the following table:

in order to reduce the computational complexity and reduce the power consumption in the hardware implementation process, FFT (Fast Fourier Transform) with different points is used for calculation for different bandwidths and sampling frequencies. The baseband processing may sample with an integer multiple of 1.92MHz, depending on the parameters of the NB-IoT protocol. In consideration of the requirements of NB-IoT protocol for low power consumption and low computational complexity, the prior art typically uses 1.92MHz sampling and 128-point FFT for calculation, and the cyclic prefix lengths are 10(l ═ 0) and 9(l ═ 1 ~ 6), respectively. Because the number of cyclic prefixes is still integer, the length of the OFDM symbol can be guaranteed to meet the symbol length and the frame length defined by the NB-IoT protocol by using the sampling frequency. A partial structural view of a transmitter and a receiver using such a conventional method is shown in fig. 1 and 2.

Referring to fig. 1, for a terminal transmitter, channel data is subjected to DFT (Discrete Fourier Transform) processing and reference signal generation, and according to resource allocation and scheduling of the channel, the channel data enters a 128-point IFFT (Inverse Fast Fourier Transform) module 101 together to perform 128-point IFFT operation processing, so as to generate an IFFT signal (i.e., an OFDM symbol), where for 128-point IFFT operation, at most 12 subcarriers are actually useful, and the rest all need zero-filling processing; then the cyclic prefix adding module 102 adds 10 or 9 pieces of length data as cyclic prefixes to each OFDM symbol according to NB-IoT protocol specifications; then, the frequency offset adjustment module 103 performs frequency offset processing of 1/2 subcarrier; and finally processed by the beamforming filter 104 for transmission output. Referring to fig. 2, for the bs receiver, the timing adjustment module 105 finds a frame header and a timing process of the received transmission signal (i.e. OFDM symbol); then the cyclic prefix removing module 106 removes the cyclic prefix added by the cyclic prefix adding module 102 according to the NB-IoT protocol; then, the 128-point FFT module 107 performs 128-point FFT on the output of the cyclic prefix removal module 106, so as to obtain channel data or a reference signal.

Because the bandwidth occupied by the NB-IoT protocol is specified to be 180kHz, and the number of available subcarriers is at most 12, a 128-point IFFT operation performed in the conventional method causes a large waste of computing resources, and increases the chip implementation area, power consumption, and cost of the NB-IoT protocol uplink.

Aiming at the defects of the traditional method, the invention provides a novel low-cost terminal uplink design scheme supporting an NB-IoT protocol, which has the core that: the method comprises the steps of caching an operation structure into an asynchronous FIFO (First in First out queue) by adopting IFFT operation with lower point number, performing multiple interpolation on IFFT operation results through different clock domains and adding corresponding control logic, thereby replacing the IFFT calculation amount of 128 points in the traditional method, meeting the frame structure and the OFDM symbol duration specified by a protocol, reducing the calculation complexity generated by OFDM symbols and the realization area, power consumption and cost of an NB-IoT protocol uplink chip to the maximum extent, and further meeting the design requirements of low cost and low power consumption of an NB-IoT protocol multicarrier signal format.

The present invention will be described in more detail with reference to the accompanying drawings, which are included to illustrate embodiments of the present invention.

Referring to fig. 3, the present invention provides an uplink multi-carrier transmitting apparatus, which includes a sampling module 300, a Q-point IFFT module 301, an R-time domain up-sampling module 302, a cyclic prefix adding module 303, a frequency offset adjusting module 304, and a beamforming filter 305.

The sampling module 300 is configured to sample a baseband signal, perform DFT processing on channel data, and generate a reference signal according to R times of the frequency of a signal output by the time domain up-sampling module, so as to obtain modulation symbol data, perform zero-padding processing on the modulation symbol data according to a resource mapping protocol of an NB-IoT protocol, and generate Q point data (i.e., discrete sampling points) as a sampling signal transmitted to the Q point IFFT module 301; the Q-point IFFT module 301 is configured to perform Q-point IFFT operation on the sampled signal, where Q is a power of 2 and less than 128, such as 4, 8, 16, 32, or 64; the R-time domain up-sampling module 302 is configured to perform R-time domain up-sampling processing on the signal output by the Q-point IFFT module 301, where a product of R and Q is equal to 128; the cyclic prefix adding module 303 is configured to add a cyclic prefix to the signal output by the R-fold time-domain upsampling module 302; the frequency offset adjustment module 304 is configured to perform frequency offset processing on the signal output by the cyclic prefix adding module 303; the beamforming filter 305 filters and performs waveform adjustment on the signal output by the frequency offset adjustment module 304 to form a transmission signal.

Since the system bandwidth of the NB-IoT protocol specification is 180kHz, and the maximum number of available subcarriers is 12, the frequency of the sampling signal output by the sampling module 300 may be 1.92MHz/R, that is, the baseband sampling frequency adopted according to the requirement is 1.92MHz/R, and the Q-point IFFT module 301 performs Q-point IFFT operation on the sampling signal. However, if the Q-point IFFT module 301 adopts 1.92MHz/R sampling frequency and Q-point IFFT operation processing, when the NB-IoT protocol parameter set according to the conventional method is used to perform 128 times of point reduction processing, the length of the cyclic prefix is not an integer, which obviously destroys the OFDM symbol length and frame length specified by the NB-IoT protocol. Therefore, when the Q-point IFFT module 301 performs Q-point IFFT operation on the sampling signal, the R-time upsampling module 302 is required to perform upsampling and adjustment on the original data, so that the generated Q-point IFFT signal is subjected to R-time upsampling to change into a 1.92MHz sampling frequency and a 128-point IFFT signal.

Usually, a complete OFDM symbol under the NB-IoT protocol includes an original symbol portion and a cyclic prefix portion, and therefore, the cyclic prefix adding module 303 adds 10 or 9 pieces of length data to a signal (i.e., the original OFDM symbol portion) output by the R-time domain upsampling module as the cyclic prefix, so as to meet the specification of the narrowband internet of things protocol on the OFDM symbol and the frame length. Further, when the original OFDM symbol length of the signal output by the R-fold time-domain up-sampling module is 0, the cyclic prefix adding module adds 10 pieces of length data to the signal output by the R-fold time-domain up-sampling module as the cyclic prefix; and when the original OFDM symbol length of the signal output by the R-time domain up-sampling module is 1-6, the cyclic prefix adding module adds 9 length data to the signal output by the R-time domain up-sampling module to serve as the cyclic prefix.

Because all sub-channels of the OFDM system are orthogonal to each other, frequency offsets such as doppler shift and the like may be generated during transmission of a wireless channel, and frequency offsets generated due to performance differences between devices at a transmitting end and a receiving end, which all affect the orthogonality of the entire communication system, resulting in OFDM inter-symbol interference and inter-subcarrier interference, and accurate frequency offset adjustment (or correction) of a transmission signal is required in order to enable the transmission signal to be correctly and reliably received and recovered by the receiving end. The frequency offset adjustment module 304 may perform frequency offset adjustment of 1/(2N) integer times of subcarriers on the signal output by the cyclic prefix adding module 303.

The working process of the uplink multi-carrier transmitting device of the present invention is described in detail below by taking an example that Q of the Q-point IFFT module 301 is 16, and R of the R-time domain up-sampling module 302 is 8, specifically as follows:

the uplink multi-carrier transmitting device needs to carry out OFDM symbol on 12 modulation symbols. For convenience of description, the 12 modulation symbols are all real numbers (consistent with complex numbers) and are random integers, as shown in fig. 4. The sampling module 300 may perform DFT processing and reference signal generation on channel data with a lower sampling frequency of 240kHz, however, when the sampling module 300 performs 128 times of point reduction processing according to NB-IoT protocol parameters set by a conventional method, the lengths of cyclic prefixes are respectively 1.25(l is 0) and 1.125(l is 1-6), and the length of the cyclic prefix is not an integer, which obviously destroys the OFDM symbol length and the frame length specified by the NB-IoT protocol, so the sampling module 300 needs to perform zero-padding processing on the 12 modulated symbol data according to the NB-IoT protocol resource mapping protocol to generate 16-point data as an output sampling signal, as shown in fig. 5, so as to be suitable for the Q-point IFFT module 301(Q is 16). After the 16-point IFFT operation of the Q-point IFFT module 301, a 16-point IFFT signal is generated, and the amplitude diagram is shown in fig. 6. The generated 16-point IFFT signal is subjected to a zero-padded 8-time domain upsampling process by an R-time domain upsampling module 302(R ═ 8), and becomes a 1.92MHz sampling frequency and a 128-point IFFT signal, i.e., the 16-point IFFT amplitude map becomes a 128-point IFFT amplitude map, as shown in fig. 7. And then the cyclic prefix adding module 303 adds 10(l is 0) and 9(l is 1-6) length data as cyclic prefixes according to the NB-IoT protocol, so as to meet the requirements on OFDM symbols and frame lengths in the protocol, then enters the frequency offset adjusting module 304 to perform frequency offset processing of 1/2 subcarriers, and forms a required transmitting signal after uniform filtering processing by the beamforming filter 205, so as to perform transmitting output.

Accordingly, for the receiving end of the base station, after receiving and using the signal sent by the uplink multi-carrier transmitting device of the present invention, it can directly use the conventional method to search for the frame header and timing processing, then remove the cyclic prefix according to the NB-IoT protocol, and perform 128-point FFT operation on the data, and then the amplitude diagram of the real part is as shown in fig. 8, and it can be seen from observation that after the 128-point FFT operation, the data is a periodic sequence with 16 units as the period, and the 16 units are consistent with the sequence adjusted after resource mapping (i.e. the data of fig. 5). Then, the receiving end performs zeroing (i.e., removing cyclic prefix) and re-ordered de-resource mapping (including 128-point FFT operation) according to the NB-IoT protocol, and then obtains the original data, as shown in fig. 9.

By comparing the data in fig. 4 and fig. 9, it can be seen that the uplink multi-carrier transmitting apparatus provided by the present invention can correctly decode the data when the receiving end of the base station uses the conventional method to decode the OFDM symbol, that is, the receiving end does not need to make any adjustment, and can also correctly decode the data.

The following analyzes the computation complexity of the conventional NB-IoT protocol-supporting uplink multicarrier transmitter shown in fig. 1 and the NB-IoT protocol-supporting uplink multicarrier transmitting apparatus of the present invention shown in fig. 3 to illustrate the effect of the uplink multicarrier transmitting apparatus of the present invention, which is as follows:

the conventional uplink multicarrier transmitter shown in fig. 1: for a modulation operation of 1 OFDM symbol, namely a 128-point IFFT operation, the method needs to be applied

complex multiplication of Nxlog₂448, complex addition, Nxlog₂N＝896。

And the uplink multi-carrier transmitting apparatus of the present invention shown in fig. 3: for modulation operations of 1 OFDM symbol, for example, Q16, i.e., 16-point IFFT operations, a need exists

complex multiplication of Nxlog₂N/2 is 32, complex addition, Nxlog₂N＝64。

It can be seen from the above that, by adopting the uplink multi-carrier transmitting device provided by the invention, the complexity of the complex multiplication and the complex addition is 1/14 of that of the traditional uplink multi-carrier transmitter, and simultaneously, the needed stored IFFT coefficient table is only 1/8 of that of the traditional uplink multi-carrier transmitter, thereby greatly reducing the realization area, the power consumption and the cost of the NB-IoT protocol uplink chip.

Referring to fig. 10, the present invention further provides a multi-carrier communication system, which includes an uplink multi-carrier transmitting apparatus and a receiving apparatus for receiving a transmission signal of the uplink multi-carrier transmitting apparatus. The uplink multi-carrier transmitting device includes a sampling module 300, a Q-point IFFT module 301, an R-time domain up-sampling module 302, a cyclic prefix adding module 303, a frequency offset adjusting module 304, and a beamforming filter 305. The sampling module 300 is configured to sample a baseband signal, perform DFT processing on channel data, and generate a reference signal according to R times of the frequency of a signal output by the time domain up-sampling module, so as to obtain modulation symbol data, perform zero-padding processing on the modulation symbol data according to a resource mapping protocol of an NB-IoT protocol, and generate Q point data (i.e., discrete sampling points) as a sampling signal transmitted to the Q point IFFT module 301; the Q-point IFFT module 301 is configured to perform Q-point IFFT operation on the sampled signal, where Q is a power of 2 and less than 128, such as 4, 8, 16, 32, or 64; the R-time domain up-sampling module 302 is configured to perform R-time domain up-sampling processing on the signal output by the Q-point IFFT module 301, where a product of R and Q is equal to 128; the cyclic prefix adding module 303 is configured to add a cyclic prefix to the signal output by the R-fold time-domain upsampling module 302; the frequency offset adjustment module 304 is configured to perform frequency offset processing on the signal output by the cyclic prefix adding module 303; the beamforming filter 305 filters and performs waveform adjustment on the signal output by the frequency offset adjustment module 304 to form a transmission signal.

The receiving device comprises a timing adjusting module 306, a cyclic prefix removing module 307 and a 128-point FFT module, wherein the timing adjusting module 306 is used for searching a frame header of a received transmitting signal and performing timing processing; a cyclic prefix removing module 307 is configured to remove a cyclic prefix in the signal output by the timing adjusting module; the 128-point FFT module 308 is configured to perform a 128-point FFT on the signal output by the cyclic prefix removal module to obtain channel data or a reference signal.

In addition, in conjunction with the uplink multi-carrier transmitting apparatus in fig. 3, the present invention further provides an uplink multi-carrier transmitting method, please refer to fig. 11, which includes the following steps:

s1001, sampling a baseband signal to form a sampling signal;

s1002, performing Q-point IFFT operation processing on the sampling signal, wherein Q is a power of 2 and is less than 128;

s1003, performing time domain up-sampling processing on the signal subjected to Q point IFFT operation processing by R times, wherein the product of M and Q is equal to 128, and the frequency of the sampling signal is one R times of the frequency of the signal subjected to the time domain up-sampling processing by R times;

s1004, adding a cyclic prefix to the signal subjected to the R-time domain up-sampling processing;

s1005, performing frequency offset processing on the signal added with the cyclic prefix;

s1006, filtering and waveform adjusting the signal after the frequency offset processing to form a transmitting signal.

In step S1003, the frequency of the signal subjected to the R-time domain up-sampling processing may be 1.92MHz, the corresponding sampling frequency in step S1001 is 1.92MHz/R, Q in step S1002 may be 4, 8, 16, 32, or 64, when the sampling frequency in step S1001 is 60kHz, Q in step S1002 is 4, and R in step S1003 is 32; when the sampling frequency in step S1001 is 120kHz, Q in step S1002 is 8, and R in step S1003 is 16; when the sampling frequency in step S1001 is 240kHz, Q in step S1002 is 16, and R in step S1003 is 8; when the sampling frequency in step S1001 is 4800kHz, Q in step S1002 is 32, and R in step S1003 is 4; when the sampling frequency in step S1001 is 960kHz, Q in step S1002 is 64, and R in step S1003 is 2.

In step S1004, 10 or 9 pieces of length data are added to the signal subjected to the R-time domain up-sampling processing as the cyclic prefix, so as to satisfy the specification of the narrowband internet of things protocol on OFDM symbols and frame lengths. When the original OFDM symbol length of the signal subjected to the R-time domain up-sampling processing is 0, adding 10 length data to the signal subjected to the R-time domain up-sampling processing as the cyclic prefix; and when the original OFDM symbol length of the signal subjected to the R-time domain up-sampling processing is 1-6, adding 9 length data to the signal subjected to the R-time domain up-sampling processing to be used as the cyclic prefix.

In step S1005, frequency offset adjustment of 1/(2N) times of subcarriers may be performed on the signal to which the cyclic prefix is added, for example, frequency offset adjustment of 1/2 subcarriers is performed on the signal to which the cyclic prefix is added, so that the transmitted signal can be correctly received and recovered by a corresponding receiving apparatus.

Referring to fig. 12, the present invention further provides a multi-carrier communication method, including the following steps:

s2001, generating a transmission signal to transmit to the outside by using the uplink multi-carrier transmission apparatus shown in fig. 3, or generating a transmission signal to transmit to the outside by using the uplink multi-carrier transmission method shown in fig. 11.

S2002, receiving the transmitting signal, and searching a frame header of the transmitting signal and performing timing processing;

s2003, removing the cyclic prefix in the timed signal;

and S2004, performing 128-point FFT on the signal with the cyclic prefix removed to obtain original channel data or a reference signal.

In summary, the uplink multi-carrier transmitting device, system and method of the present invention are suitable for the multi-carrier signal format of NB-IoT protocol, and when the protocol specifies the frame structure and the OFDM symbol duration, the IFFT operation with lower number of points and the interpolation of corresponding multiple and corresponding control logic increase for the IFFT operation result through different clock domains are performed, thereby replacing the 128-point IFFT calculation amount in the conventional method, greatly reducing the design complexity of the terminal chip, and reducing the implementation area, power consumption and cost, thereby better meeting the design requirements of NB-IoT for low cost and low power consumption. In addition, the receiving end of the transmitted signal can adopt the traditional method to receive and demodulate, and does not need to make any adjustment and change, thereby reducing the calculation degree and ensuring better applicability and compatibility.

It will be apparent to those skilled in the art that various changes and modifications may be made in the invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims

1. An uplink multi-carrier transmitting apparatus supporting an NB-IoT protocol, comprising:

2. The uplink multicarrier transmitting apparatus according to claim 1, further comprising a sampling module, configured to sample a baseband signal by one R times a frequency of a signal output by said R time-domain up-sampling module to form said sampled signal.

3. The uplink multicarrier transmitting apparatus according to claim 2, wherein the frequency of the signal output by said R-fold time-domain up-sampling module is 1.92 MHz; when Q is 4, the frequency of the sampling signal is 60kHz, and R is 32; when Q is 8, the frequency of the sampling signal is 120kHz, and R is 16; when the Q is 16, the frequency of the sampling signal is 240kHz, and R is 8; when the Q is 32, the frequency of the sampling signal is 480kHz, and R is 4; when Q is 64, the frequency of the sampling signal is 960kHz, and R is 2.

4. The uplink multi-carrier transmitting device of claim 1, wherein the cyclic prefix adding module adds 10 or 9 length data to the signal output by the R-fold time-domain up-sampling module as the cyclic prefix so as to satisfy the requirements of narrowband internet of things protocols on OFDM symbols and frame lengths.

5. The uplink multi-carrier transmitting apparatus according to claim 4, wherein when the original OFDM symbol length of the signal output by the R times time domain up-sampling module is 0, the cyclic prefix adding module adds 10 length data to the signal output by the R times time domain up-sampling module as the cyclic prefix; and when the original OFDM symbol length of the signal output by the R-time domain up-sampling module is 1-6, the cyclic prefix adding module adds 9 length data to the signal output by the R-time domain up-sampling module to serve as the cyclic prefix.

6. The uplink multi-carrier transmitting apparatus according to claim 1, wherein the frequency offset adjusting module performs frequency offset processing on 1/2 sub-carriers of the signal output by the cyclic prefix adding module.

7. A multi-carrier communication system supporting an NB-IoT protocol, comprising: the uplink multi-carrier transmitting apparatus according to any one of claims 1 to 6 and a receiving apparatus that receives a transmission signal of the uplink multi-carrier transmitting apparatus.

8. The multi-carrier communication system of claim 7, wherein said receiving means comprises:

9. An uplink multi-carrier transmission method supporting an NB-IoT protocol, comprising:

10. The uplink multicarrier transmission method according to claim 9, wherein a baseband signal is sampled by one R times a frequency of the time-domain up-sampled signal to form the sampled signal.

11. The uplink multicarrier transmission method according to claim 10, wherein said R times frequency of the time-domain up-sampled signal is 1.92MHz, when said Q is 4, said frequency of the sampled signal is 60kHz, R is 32; when Q is 8, the frequency of the sampling signal is 120kHz, and R is 16; when the Q is 16, the frequency of the sampling signal is 240kHz, and R is 8; when the Q is 32, the frequency of the sampling signal is 480kHz, and R is 4; when Q is 64, the frequency of the sampling signal is 960kHz, and R is 2.

12. The uplink multi-carrier transmission method according to claim 9, wherein 10 or 9 length data are added to the signal after R-time domain up-sampling processing as the cyclic prefix to satisfy the specification of the narrowband internet of things protocol on OFDM symbols and frame lengths.

13. The uplink multi-carrier transmission method according to claim 12, wherein when the original OFDM symbol length of the R times time-domain up-sampled processed signal is 0, 10 length data are added to the R times time-domain up-sampled processed signal as the cyclic prefix; and when the original OFDM symbol length of the signal subjected to the R-time domain up-sampling processing is 1-6, adding 9 length data to the signal subjected to the R-time domain up-sampling processing to be used as the cyclic prefix.

14. The uplink multi-carrier transmission method according to claim 9, wherein the signal added with the cyclic prefix is subjected to frequency offset processing of 1/2 sub-carriers.

15. A multicarrier communication method supporting NB-IoT protocol, wherein the uplink multicarrier transmission apparatus in any of claims 1 to 6 is adopted to generate transmission signals to transmit outward, or the uplink multicarrier transmission method in any of claims 9 to 14 is adopted to generate transmission signals to transmit outward.

16. The multi-carrier communication method of claim 15, further comprising:

removing the cyclic prefix in the timed signal;