CN114697180B - Uplink random access signal synchronous detection method applied to next generation Internet of things communication system - Google Patents
Uplink random access signal synchronous detection method applied to next generation Internet of things communication system Download PDFInfo
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- H—ELECTRICITY
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- H04L27/26—Systems using multi-frequency codes
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- H04W74/0833—Non-scheduled or contention based access, e.g. random access, ALOHA, CSMA [Carrier Sense Multiple Access] using a random access procedure
Abstract
The invention discloses an uplink random access signal synchronous detection method applied to a next generation internet of things communication system, which comprises the following steps that firstly, an access signal sequence is subjected to multiplexing fast Fourier transform operation to obtain a frequency domain received signal sequence; step two, carrying out differential calculation of a point of separation on each time domain symbol on the frequency domain received signal sequence, accumulating the calculation result and a locally stored historical signal, accumulating differential calculation results of a point of separation of all the receiving antenna sequences under the current time domain symbol, and then carrying out local storage; traversing the local pre-stored u-value related sequence, carrying out matching multiplication with the final frequency domain sequence and carrying out coherent accumulation; and step four, setting a threshold, and obtaining a corresponding u value and a cyclic displacement value according to the phase information of the corresponding peak position when the coherent accumulation result of the step three exceeds the threshold. The method reduces the demands on FFT and IFFT modules, reduces the calculation complexity and saves the resources.
Description
Technical Field
The invention relates to a synchronous detection method of a communication system, in particular to a synchronous detection method of an uplink random access signal applied to a communication system of the next generation of internet of things.
Background
The existing uplink random access channel detection flow is as follows: generally, a method based on coherent detection is adopted, for a Preamble (Preamble) signal sequence, first, after removing a Cyclic Prefix (CP), a Fast Fourier Transform (FFT) with a point length of N (Preamble time domain symbol sequence length) is executed, and 24576points are given to a Preamble signal of 2.5KHz. The FFT is performed for each repetition.
After the FFT is completed, the frequency domain received signal is extracted from the corresponding frequency domain position. Considering that the transmitting end may contain multiple groups of different base sequences and cyclic shifts, it is necessary to traverse all possible base sequences corresponding to u values and cyclic shift values C v Corresponding cyclic shifts. Considering that a coherent detection mode is adopted, different cyclic shifts can be reflected in different time domain peak positions after Inverse Fast Fourier Transform (IFFT), so that only a matched filter is needed for the transmission sequences of different u-value base sequences, and the matched filter (IMF) is needed for the sequences after FFT, namely, the frequency domain point is multiplied by the local sequenceConjugation.
After performing matched filtering, an IFFT operation is performed on each filtered result, one IFFT process being performed each time. After performing the IFFT, a peak value is generated for the transmission sequence of u selected by the transmitting end, and the position of the peak value is selected by C v And the delay value generated by the air interface channel.
The results of multiple sets of repeated IFFT-windows are accumulated, taking into account the reduction of channel correlation due to frequency offset and channel variations, and thus coherent accumulation or modulo incoherent accumulation may be chosen here. And after the accumulation is finished, the peak amplitude is obtained, and judgment is carried out. And determining that a plurality of Preamble accesses exist in the current resource according to the positions and the number of the peaks, and estimating the time delay and the base sequence of the accesses.
The traditional detection method based on the frequency domain coherent detection has the advantages of mature framework and good performance of a coherent detection algorithm. However, the main disadvantage is that a special FFT module circuit needs to be configured for Preamble detection, since the carrier spacing selected by the Preamble sequence differs greatly from the data channel, especially in the case of 2.5kHz and 5kHz. These circuits can only perform Preamble detection. Meanwhile, for 5 GNRs, since the carrier intervals vary greatly, designing a special Preamble detector (FFT) for different carrier intervals will greatly increase the complexity of the design.
In addition, since 5G NR uses more time-frequency resources as the Preamble resources, the conventional method based on coherent detection needs to perform a large number of IFFT operations, which also increases implementation complexity.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide an uplink random access signal synchronous detection method applied to a next generation internet of things communication system, which reduces the demands on FFT and IFFT modules, reduces the computation complexity and saves resources.
The technical scheme of the invention is as follows: an uplink random access signal synchronous detection method applied to a next generation internet of things communication system comprises the following steps: step one, multiplexing fast Fourier transform operation is carried out on an access signal sequence to obtain a frequency domain receiving signal sequence; step two, carrying out differential calculation of one point apart on each time domain symbol on the frequency domain received signal sequence obtained in the step one, accumulating the calculation result and a locally stored historical signal, accumulating differential calculation results of one point apart of all the received antenna sequences under the current time domain symbol, then carrying out local storage, and repeating the step for all the time domain symbols; step three, reading a locally stored final frequency domain sequence after repeating the step two, traversing a locally pre-stored u-value related sequence, carrying out matched multiplication with the final frequency domain sequence, and carrying out coherent accumulation; setting a threshold, and obtaining a corresponding u value and a cyclic displacement value according to the phase information of the corresponding peak position when the coherent accumulation result in the third step exceeds the threshold;
the multiplexing fast fourier transform operation includes step1, removing a cyclic prefix, which is determined based on a cyclic prefix length of a data channel sequence in the access signal sequence, and performing fast fourier transform on a signal falling within a fast fourier transform window; step2, extracting frequency domain signals in the inverse process of frequency domain mapping of the transmitted signals; step3, carrying out phase compensation on the frequency domain sequence under each OFDM symbol of the leading channel sequence in the access signal sequence; and 4, multiplying each OFDM symbol by the corresponding frequency domain linear rotation vector on the frequency domain to perform time offset compensation.
Further, the uplink random access signal synchronous detection method applied to the next generation of internet of things communication system comprises the following steps: step one, multiplexing fast Fourier transform operation is carried out on an access signal sequence to obtain a frequency domain receiving signal sequence; step two, performing second-order differential calculation on each time domain symbol on the frequency domain received signal sequence obtained in the step one, and performing coherent accumulation on calculation results; setting a threshold, and obtaining a corresponding u value and a cyclic displacement value according to phase information of a corresponding peak value position when the coherent accumulation result in the step two exceeds the threshold;
the multiplexing fast fourier transform operation includes step1, removing a cyclic prefix, which is determined based on a cyclic prefix length of a data channel sequence in the access signal sequence, and performing fast fourier transform on a signal falling within a fast fourier transform window; step2, extracting frequency domain signals in the inverse process of frequency domain mapping of the transmitted signals; step3, carrying out phase compensation on the frequency domain sequence under each OFDM symbol of the leading channel sequence in the access signal sequence; and 4, multiplying each OFDM symbol by the corresponding frequency domain linear rotation vector on the frequency domain to perform time offset compensation.
Further, the window length of the fast Fourier transform of the step1 is determined by the method according to Δf FFT Determined carrier spacing and bandwidth determination, Δf FFT The minimum value of RA carrier spacing and data channel carrier spacing configured for the cell.
Further, the compensation coefficient during phase compensation in the step3 is as follows
Wherein,for the receiver center frequency, < >>For the accumulated time of the start moment of each symbol relative to the reference moment +.>For the cyclic prefix length of each symbol.
Further, the frequency domain linear rotation vector is
Wherein,phase increment factor ρ j It is indicated that the number of the elements is,
wherein the method comprises the steps ofA cyclic prefix length for random access preamble, < >>Cyclic prefix length, N, for data channel OFDM symbols FFT For the window length of the fast fourier transform, K is a multiple of the carrier spacing of the random access channel relative to the carrier spacing of the data channel, K 1 Is the resource block position index of the data channel corresponding to the carrier starting point of random access,/for the data channel>Is the offset of the carrier starting position of random access in the resource block.
Further, when the preamble channel sequence is Format0/1/2/3, the multiplexing fast fourier transform operation further includes step5 of superposing the frequency domain signals after the fast fourier transform is processed by the plurality of fast fourier transform windows; step6, performing linear interpolation on the superimposed signals to obtain signals on carrier points with carrier intervals of 1.25KHz or 2.5KHz, wherein the frequency band linear rotation vector in the step4 is
Wherein,phase increment factor ρ j It is indicated that the number of the elements is,
ρ j_2 ＝mod(j*N FFT ，L 0 )
wherein N is FFT For the window length of the fast fourier transform, K is a multiple of the carrier spacing of the random access channel relative to the carrier spacing of the data channel, K 1 Is a resource block position index of the data channel corresponding to the carrier start point of the random access,is the offset of the carrier starting position of random access in the resource block.
Further, the u-value correlation sequence is……，L RA For accessing the length of the signal sequence.
Compared with the prior art, the invention has the advantages that:
the method adopts the FFT module multiplexing the data channel and the random access channel, combines phase and timing estimation compensation and linear interpolation operation to realize compatibility of different carrier intervals and different Preamble formats. The traditional Preamble detection scheme based on coherent detection is improved, incoherent detection is adopted, and the coherent accumulation of the differential results of a plurality of groups of time domain received signals and space domain received signals is utilized, so that the computational complexity is effectively reduced, and the detection performance is ensured. Meanwhile, under the special scene that the number of the u value sequences is large, algorithm deformation of second-order difference can be adopted to further reduce the searching and storage cost of the u values.
Drawings
Fig. 1 is a flow chart of an uplink random access signal synchronization detection method applied to a next generation internet of things communication system according to an embodiment of the present invention.
Fig. 2 is a schematic diagram of a reusable fast fourier transform architecture.
Fig. 3 is a flowchart of an uplink random access signal synchronization detection method applied to a next generation internet of things communication system according to a preferred embodiment.
Detailed Description
The invention is further illustrated, but is not limited, by the following examples.
Referring to fig. 1 and 2, the method for synchronously detecting uplink random access signals applied to a communication system of the next generation internet of things according to the present embodiment includes
Step one
Step1: removing the cyclic prefix CP and performing fast Fourier transform FFT
FFT Point number N FFT Needs to be given by the minimum value of the RA carrier spacing (considering only Preamble format a/B/C/D) and the data channel carrier spacing of the cell configuration, i.e.
Δf FFT ＝Min(Δf,Δf RC )
Whereas the frequency of the CP interception and FFT needs to be given by the channel corresponding to the large value of both.
For example, when the data channel is a carrier interval of 30KHz and the random access channel is a carrier interval of 15KHz, considering the case of the bandwidth agreement (20M case), the FFT point number corresponding to 30KHz is 1024 and the FFT point number of 15KHz is 2048. The scheme of the two multiplexing FFT modules at this time is based on the FFT point number of 15KHz, namely 2048 point FFT, and the CP extraction and FFT operation is performed with a symbol period of 30KHz and a CP length.
The received signal sequence includes a data channel sequence and a Preamble (Preamble) channel sequence. The preamble channel sequence contains Format A/B/C/D or Format0/1/2/3 compatible with LTE. Δf obtained according to the above FFT And determining a carrier interval, and obtaining a corresponding FFT window length N based on the carrier interval and the bandwidth.
The cyclic prefix CP is removed from the received signal sequence, and an FFT operation based on a window of length N is performed on the signal falling within the FFT window. Where CP is the CP length based on the data channel.
For the case that the Preamble Format is a/B/C/D, since the Preamble channel sequence is that a plurality of repeated symbols are directly connected (no cyclic prefix CP is in the middle), and meanwhile, since the formats adopt a carrier interval resource set consistent with the data channel, when the RA carrier interval is greater than or equal to the data carrier interval, the symbol length of the Preamble will be less than or equal to the symbol length of the data channel. Thus, with this operation, the previous Preamble symbol corresponds to the CP of the next Preamble (since all the Preamble symbols transmit signals in unison). Such FFT operations therefore correspond to performing FFTs on sequences delayed by different cyclic shifts under different symbols. And when the RA carrier interval is smaller than the data carrier interval, the FFT window length is calculated with the RA carrier interval as the FFT carrier interval, and the data channel carrier interval as the frequency at which the FFT is performed.
After completion of the FFT transformation, sequential frequency domain signal decimation, phase compensation and timing compensation will be performed.
Step2: frequency domain signal decimation
Wherein the frequency domain symbol extraction is performed according to the inverse of the frequency domain mapping of the transmit part. The frequency domain mapping process of the transmitting part may be described based on the following formula.
K＝Δf/Δf RA
Wherein the method comprises the steps ofFor the frequency domain sequence y u,v (n) a frequency domain sequence obtained by multiplying the power adjustment factor. According to the above, the selected frequency domain resource is +.>Starting length L RA Is from +.>The beginning Preamble time domain samples the symbol. k (k) 1 And the RB position is the RB position corresponding to the frequency domain carrier wave where the Preamble is located. In the calculation formula, the offset of BWP based on the Preamble is given>Therefore, the BWP position is determined according to the offset of the BWP in the whole resource grid area, and the BWP position is determined according to the offset of the Preamble relative to the BWP>To determine the frequency domain resource starting position of the Preamble. After the initial position of the frequency domain resource is determined, according to the actual selected frequency domain resource RB number n selected by the terminal RA To finally determine the frequency domain RB position k occupied by the Preamble 1 . Since the RB is expressed based on the carrier interval of the data channel, when the carrier interval of the random access is different from the carrier interval of the data channel, it is necessary to multiply the K factor to switch to the carrier interval of the random access. After this, the intra-RB offset selected based on the protocol is superimposed +>Finally, the position of the Preamble frequency domain transmission starting carrier is obtained.
Step3: phase compensation
The frequency domain symbol extraction is followed by a phase compensation operation. Since the uplink data channel needs to be subjected to symbol-by-symbol phase adjustment when receiving, and the operation does not need to be performed on the Preamble signal, if multiplexing uplink data and the Preamble are processed together, a frequency domain sequence phase compensation for each symbol needs to be added to the Preamble, and the compensation coefficient is formed byGiven a givenWherein
Wherein,is the receiver center frequency,/>For the accumulated time of the start moment of each symbol relative to the reference moment +.>These parameters all vary with the system parameter mu for the CP length of each symbol.
Step4: time offset compensation
The Preamble signal sequence also needs to perform a response operation since the de-CP and FFT of the reference data channel do not. However, since the corresponding CP is not inserted between the symbols of the Preamble sequence repetition, a plurality of sets of repeated transmission Preamble symbols are directly concatenated. The design has the advantages that the former Preamble symbol becomes the cyclic prefix of the latter Preamble, so that a longer cyclic prefix is realized, the length reaches one symbol, and a larger cell searching range can be realized.
For the above reasons, when implementing the decp and FFT operations using the same architecture, different starting offsets are generated for the data in the FFT window of each Preamble, that is, the value of the initial position offset is determined by the symbol. In this case, compensation for this additionally generated time offset is required. Since the offset of the time domain brings about linear phase rotation of the frequency domain, the receiver calculates the time domain offset of each OFDM symbol according to the offset determined in advance, thereby multiplying the corresponding frequency domain linear rotation vector on the frequency domain, and realizing compensation of the additional time delay. The frequency domain linear phase can be expressed as the following formula
Wherein,phase increment factor ρ j It is indicated that the number of the elements is,
wherein the method comprises the steps ofA cyclic prefix length of a random access Preamble, < >>Cyclic prefix length, k, of data channel OFDM symbols 1 Is the resource block position index of the data channel corresponding to the carrier starting point of random access,/for the data channel>Is the offset of the carrier starting position of random access in the resource block.
Step5: frequency domain interpolation (for Format0/1/2/3 only)
The above is the step under the corresponding Format a/B/C/D, and under the condition of the corresponding Format0/1/2/3, the symbol length 24576points of the Preamble is due to the carrier spacing of 2.5KHz and 5KHz, so that the FFT to be designed for this length will only be used for Preamble detection. Both the length and frequency of FFTSize are calculated depending on the carrier spacing of the data channel. Since 24576 corresponds to a carrier spacing of 2.5kHZ, only FFTs based on this length can result in a correct data channel on the 2.5kHZ carrier, whereas FFTs less than this length result in a frequency domain signal with a carrier spacing of 15kHZ or greater. For several cases of Format0/1/2/3, the data portion of the Preamble is a non-repeated 24576 (at a carrier interval of 2.5 KHz) point. The FFT according to the data channel within the length of these points corresponds to dividing the sequence of length 24576points into N-point length FFTs, i.e. a segmented FFT operation.
The principle of the transformation is as follows:
first, the original length L 0 (24576points@2.5KHz) L is performed once on the Preamble receiving signal 0 The FFT of the points corresponds to dividing the original length intoSegments, each segment having a length of N FFT Point, N for each segment FF□ According to the data of (2) at L 0 The inner position is added with 0 and then the length is L 0 Is finally repeated +.>Such FFT processing is repeated, and the frequency domain results are superimposed. Since the FFT is linear, the process can be equivalent to L of full length at a time 0 Is a FFT of (c).
Second, the FFT after each segment is subjected to single zero padding can be equivalent to the length N FFT And then linearly interpolates to 2.5KHz. Because of the FFT of zero padding of each segment, the segment number of non-zero position is circularly shifted to the right by N FFT Thus executing N FFT Before the FFT re-interpolation process, the frequency domain signal after FFT transformation needs to be multiplied by the frequency domain phase rotation according to the corresponding cyclic shift result of each segment, and the rotation value is as follows:
ρ j_2 ＝mod(j*N FFT ，L 0 )
and finally, accumulating the frequency domain interpolation results obtained by the multi-stage FFT.
Based on the principle, the equivalent treatment for Format0/1/2/3 can be obtained, and the specific process is as follows:
step1': the decp and FFT processes are as described above, wherein the FFT window length is N FFT Refer to Step1.
Step2': this frequency domain data needs to be extracted through the process described above, with reference to Step2.
Step3': the frequency domain data is phase compensated, refer to Step3.
Step4': the frequency domain data needs to be subjected to timing compensation, referring to Step4, in which the parameters of the cyclic shift are referencedρ is j_2 。
Step5': and superposing the frequency domain signals after the FFT window processing FFT.
Step6': and performing linear interpolation on the superimposed signals to obtain signals at carrier points with carrier intervals of 1.25KHz (or 2.5 KHz).
After the processing in the step one is completed to obtain a frequency domain sequence, the following optimized incoherent detection algorithm is executed.
From the RA transmission scheme, it can be known that the terminal can select a plurality of continuous frequency domain resources, and when the selection is performed, the terminal will select and transmit a continuous time domain Slot corresponding to the frequency domain resources, and when the Slot is selected, the terminal will transmit all candidate time domain positions in the Slot, and when the transmission is performed, the frequency domain positions are not changed, and all time domain sequences (including repeated sequences) are occupied. Therefore, after the terminal selects the time-frequency resource, the base station side can have time domain at most, and the space domain two-dimensional resource can be accumulated and combined. The airspace mainly comprises a plurality of receiving antenna ports, which correspond to a digital beam forming scheme, the analog beam forming scheme selects resources corresponding to corresponding SSB numbers through a terminal, and the base station correspondingly uses a receiving space filter to realize optimal receiving.
Conventional random detection algorithms based on coherent accumulation, when aiming at multiple time-frequency RA resources and multiple receiving antenna ports, cannot perform coherent accumulation combining before IFFT. This is mainly because at this stage, the base station has no channel information of the terminal, and cannot combine for multiple receiving antenna ports, and time resources of multiple random access channels, in case the channel is unknown. If the signals cannot be directly combined, the IFFT calculation needs to be performed for each resource (including time domain or space domain), and then the incoherent combination is performed after the IFFT, which results in a decrease in detection performance, and more importantly, a significant increase in computational complexity.
In this case, the scheme based on incoherent detection is adopted, so that the operation complexity of the operation can be effectively reduced, the received signal of the multi-antenna port is subjected to operations such as CP removal, FFT, frequency domain extraction, phase compensation, timing compensation, (linear interpolation) and the like under the common FFT architecture, and then the received signal sequence of the frequency domain is obtained. The sequence comprises a plurality of sets of adjacent time sequences and a plurality of sets of different receiving antennas.
For transmission as ZC sequences, a first order differential approach is used here to calculate the received phase difference between adjacent two frequency domain symbols. Because of differential operation, the adjacent two frequency domain position channels can be regarded as consistent, so that the differential correlation can eliminate the difference of the channels, and the coherent accumulation of a plurality of time domain symbols and a plurality of receiving antennas can be realized.
And accumulating the frequency domain signals on the current symbol with the history signals stored in the storage space 1, accumulating all the receiving antenna sequences under the current symbol to perform the first-order difference result, and storing the first-order difference result in the space 1.
When all time domain symbol processing is completed, the final frequency domain sequence is read out from the memory space 1, and the u, v decision is made as follows.
Considering the nature of ZC sequences, the differential correlation of two sets of ZC sequences can be written as,
from the above equation, it can be seen that the sequence after differential correlation at a distance will be out of phase by a phase difference comprising C V The constants of the information are superimposed with a primary term that varies with u.
By pre-storing the sequence in the local sequence… …. A group needs to be pre-stored for each group u, stored in the memory space 2.
In the actual implementation process, traversing and selecting different u, reading out the corresponding data in the storage space 2, multiplying the data by the final frequency domain sequence, performing coherent accumulation, comparing whether the result of coherent accumulation exceeds a threshold, and when the result exceeds the threshold, obtaining C according to the phase information of the peak position of the data V And (5) taking a value. Finally, all u and v (C V ) And (5) taking a value.
Compared with coherent detection, the optimized incoherent detection can effectively reduce the operation complexity, and the detection signal to noise ratio is improved through the coherent accumulation combination benefit brought by difference, so that the detection performance is improved. However, the u value also needs to be traversed during the final detection. When there are a maximum of 64 groups of base sequences in extreme cases, 64 groups of traversals and storages may be required, which may lead to an increase in computational overhead. An optimized implementation is therefore proposed below.
Referring to fig. 3, after the processing in the first step is completed to obtain a frequency domain sequence, a second order difference processing is adopted, and the principle is as follows.
Based on the foregoing, first order difference is considered to obtain the following difference sequence
……
And then carrying out differential with a small interval on the sequences to obtain a second-order differential, wherein the result is as follows:
……
therefore, the coherent accumulation post-decision can be performed based on the result of the second-order difference, and the value of u is judged according to the result of the phase because the phase is only related to u. Specifically, whether the threshold is exceeded is judged according to the peak value. And after the threshold is exceeded, u value judgment is carried out according to the phase value of the peak value position. When the u value decision is completed, v (C V ) Is determined by the decision(s).
Claims (7)
1. The uplink random access signal synchronous detection method applied to the next generation of internet of things communication system is characterized by comprising the following steps: step one, multiplexing fast Fourier transform operation is carried out on an access signal sequence to obtain a frequency domain receiving signal sequence; step two, carrying out differential calculation of one point apart on each time domain symbol on the frequency domain received signal sequence obtained in the step one, accumulating the calculation result and a locally stored historical signal, accumulating differential calculation results of one point apart of all the received antenna sequences under the current time domain symbol, then carrying out local storage, and repeating the step for all the time domain symbols; step three, reading a locally stored final frequency domain sequence after repeating the step two, traversing a locally pre-stored u-value related sequence, carrying out matched multiplication with the final frequency domain sequence, and carrying out coherent accumulation; setting a threshold, and obtaining a corresponding u value and a cyclic displacement value according to the phase information of the corresponding peak position when the coherent accumulation result in the third step exceeds the threshold;
the multiplexing fast fourier transform operation includes step1, removing a cyclic prefix, which is determined based on a cyclic prefix length of a data channel sequence in the access signal sequence, and performing fast fourier transform on a signal falling within a fast fourier transform window; step2, extracting frequency domain signals in the inverse process of frequency domain mapping of the transmitted signals; step3, carrying out phase compensation on the frequency domain sequence under each OFDM symbol of the leading channel sequence in the access signal sequence; and 4, multiplying each OFDM symbol by the corresponding frequency domain linear rotation vector on the frequency domain to perform time offset compensation.
2. The uplink random access signal synchronous detection method applied to the next generation of internet of things communication system is characterized by comprising the following steps: step one, multiplexing fast Fourier transform operation is carried out on an access signal sequence to obtain a frequency domain receiving signal sequence; step two, performing second-order differential calculation on each time domain symbol on the frequency domain received signal sequence obtained in the step one, and performing coherent accumulation on calculation results; setting a threshold, and obtaining a corresponding u value and a cyclic displacement value according to phase information of a corresponding peak value position when the coherent accumulation result in the step two exceeds the threshold;
the multiplexing fast fourier transform operation includes step1, removing a cyclic prefix, which is determined based on a cyclic prefix length of a data channel sequence in the access signal sequence, and performing fast fourier transform on a signal falling within a fast fourier transform window; step2, extracting frequency domain signals in the inverse process of frequency domain mapping of the transmitted signals; step3, carrying out phase compensation on the frequency domain sequence under each OFDM symbol of the leading channel sequence in the access signal sequence; and 4, multiplying each OFDM symbol by the corresponding frequency domain linear rotation vector on the frequency domain to perform time offset compensation.
3. The method for synchronously detecting uplink random access signals applied to the communication system of the next generation of the internet of things according to claim 1 or 2, wherein the window length of the fast fourier transform of the step1 is determined by the following methodDetermined carrier spacing and bandwidth determination, +.>The minimum value of RA carrier spacing and data channel carrier spacing configured for the cell.
4. The method for synchronously detecting the uplink random access signals applied to the communication system of the next generation of the internet of things according to claim 1 or 2, wherein the compensation coefficient during phase compensation in the step3 is，/>Wherein (1)>For the receiver center frequency, < >>For the accumulated time of the start moment of each symbol relative to the reference moment +.>For the cyclic prefix length of each symbol.
5. According to claimThe uplink random access signal synchronization detection method applied to the next generation internet of things communication system as set forth in claim 1 or 2, wherein the frequency domain linear rotation vector is，
Wherein,phase increment factor->It is indicated that the number of the elements is,wherein->A cyclic prefix length for random access preamble, < >>A cyclic prefix length of the data channel OFDM symbol, < >>Window length for fast fourier transform, +.>Is a multiple of the carrier spacing of the random access channel relative to the carrier spacing of the data channel, +.>Is the resource block position index of the data channel corresponding to the carrier starting point of random access,/for the data channel>Is the offset of the carrier starting position of random access in the resource block.
6. According to claimThe uplink random access signal synchronous detection method applied to the next generation internet of things communication system according to claim 1 or 2, wherein when the preamble channel sequence is Format0/1/2/3, the multiplexing fast fourier transform operation further comprises a step5 of superposing frequency domain signals after a plurality of fast fourier transform windows process fast fourier transform; step6, performing linear interpolation on the superimposed signals to obtain signals on carrier points with carrier intervals of 1.25KHz or 2.5KHz, wherein the frequency band linear rotation vector in the step4 isWherein, the method comprises the steps of, wherein,phase increment factor->Expressed as->Wherein->Window length for fast fourier transform, +.>Is a multiple of the carrier spacing of the random access channel relative to the carrier spacing of the data channel, +.>Is the resource block position index of the data channel corresponding to the carrier starting point of random access,/for the data channel>Offset in resource block for carrier start position of random access, < >>For the preamble channel sequenceThe length of the column.
7. The method for synchronously detecting the uplink random access signals applied to the communication system of the next generation of the internet of things according to claim 1, wherein the u-value related sequence is，/>,……，L RA For accessing the length of the signal sequence.
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