CN107769816B - Chirp spread spectrum communication system receiver time synchronization system and method - Google Patents

Chirp spread spectrum communication system receiver time synchronization system and method Download PDF

Info

Publication number
CN107769816B
CN107769816B CN201711060079.7A CN201711060079A CN107769816B CN 107769816 B CN107769816 B CN 107769816B CN 201711060079 A CN201711060079 A CN 201711060079A CN 107769816 B CN107769816 B CN 107769816B
Authority
CN
China
Prior art keywords
module
signal
spread spectrum
chirp
signals
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN201711060079.7A
Other languages
Chinese (zh)
Other versions
CN107769816A (en
Inventor
陆许明
徐永键
谭洪舟
郑燕平
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
SYSU HUADU INDUSTRIAL SCIENCE AND TECHNOLOGY INSTITUTE
National Sun Yat Sen University
Original Assignee
SYSU HUADU INDUSTRIAL SCIENCE AND TECHNOLOGY INSTITUTE
National Sun Yat Sen University
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by SYSU HUADU INDUSTRIAL SCIENCE AND TECHNOLOGY INSTITUTE, National Sun Yat Sen University filed Critical SYSU HUADU INDUSTRIAL SCIENCE AND TECHNOLOGY INSTITUTE
Priority to CN201711060079.7A priority Critical patent/CN107769816B/en
Publication of CN107769816A publication Critical patent/CN107769816A/en
Application granted granted Critical
Publication of CN107769816B publication Critical patent/CN107769816B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/69—Spread spectrum techniques
    • H04B1/7163—Spread spectrum techniques using impulse radio
    • H04B1/717—Pulse-related aspects
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/69—Spread spectrum techniques
    • H04B1/7163—Spread spectrum techniques using impulse radio
    • H04B1/7183—Synchronisation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/69—Spread spectrum techniques
    • H04B1/7163—Spread spectrum techniques using impulse radio
    • H04B1/719—Interference-related aspects
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L7/00—Arrangements for synchronising receiver with transmitter
    • H04L7/0079—Receiver details

Abstract

The invention provides a Chirp spread spectrum communication system receiver time synchronization system and a method, wherein a signal-to-noise ratio enhancement module of the system comprises a modulus taking module, a gain obtaining module, a delayer, a merging module and a gain obtaining module, wherein the modulus taking module eliminates phase difference among symbols, and the gain obtaining module strengthens useful signals; the combined spread spectrum modulation module uses the combined Chirp signal to perform spread spectrum modulation; after obtaining the signal which is modulated by the combined spread spectrum, received by the matched filtering and enhanced by the signal-to-noise ratio, the peak value searching of the narrow-band pulse after the matched filtering is reduced to a symbol period through a noise threshold value set in the judging module, and the peak value searching module captures the moment of the peak value in the symbol period to realize time synchronization. The invention solves the problem of misjudgment of the synchronization time caused by integral multiple symbol periods of difference between the actual synchronization and the ideal synchronization by adding the judgment module in the synchronization module, and improves the timing precision. Meanwhile, the complexity of the algorithm is reduced due to the reduction of the search range of the synchronous time.

Description

Chirp spread spectrum communication system receiver time synchronization system and method
Technical Field
The invention relates to the field of low-power-consumption wide area networks, in particular to a time synchronization system and a time synchronization method for a Chirp spread spectrum communication system receiver.
Background
Among a plurality of wireless technologies related to the internet of things, the LoRa technology in a low power consumption wide area network (LPWAN) is a hotspot in recent years, and LoRa is a long-distance wireless transmission scheme based on a spread spectrum technology popularized by Semtech corporation in the united states, and has the characteristics of low power consumption, low cost, wide coverage and large connection.
There are four main methods for the current spread spectrum technology: direct sequence spread spectrum, frequency hopping spread spectrum, time hopping spread spectrum and linear frequency modulation, and the linear pulse frequency modulation (CSS) belongs to the linear frequency modulation and is a key technology of a physical layer of an LoRa protocol. Chirp spread spectrum refers to a frequency sweep signal with a large bandwidth formed by linearly sweeping a carrier frequency of a system through a frequency range in one symbol period. CCS is adopted as a physical layer transmission technology in Chirp spread spectrum communication, and the Chirp spread spectrum communication has the advantages of low power consumption, long distance, low complexity and strong anti-interference capability.
In a digital communication system, the quality of a synchronization algorithm directly affects the reliability of the communication system, and when the performance of the synchronization algorithm is poor, the whole communication system may not work normally. After matched filtering, the main lobe width of output pulse of the Chirp signal of the Chirp system is in inverse proportion to the signal bandwidth, and the CSS communication system is wide in signal bandwidth and short in pulse duration, so that the time synchronization algorithm of the Chirp receiver is required to have good performance when the optimal sampling time of the narrow-band pulse is confirmed.
In the Chirp receiver, common time synchronization algorithms include a threshold method and a peak value searching method. The threshold method is to set a larger threshold value first, and when the output value of the matched filter is larger than the threshold value, that is, the moment is taken as the synchronization moment. In addition, when the transmission environment of the signal is severe, the peak value of the compressed pulse output by matching is smaller than the threshold value, and a packet loss phenomenon occurs at this time. Therefore, the threshold method is not applicable when the signal-to-noise ratio is low and the environment is too severe. The initial value in the peak search method takes a value greater than the noise power threshold. Is provided with two registers R1、R2，R1Storing an initial value, R2Initialized to 0 for storing more than R1Input values of I and R2The maximum value after comparison. When a symbol is sampled at N points, the peak search method needs to perform N comparisons, but at hard levelThe difficulty is great when the piece is realized. After that, some researches introduce the interference suppression technology into the CSS system, which enhances the anti-interference capability to a certain extent, but this method has a drawback that when the actual synchronous sampling differs from the ideal synchronous by an integer multiple of a symbol period, the sampling value is higher, which will bring about the erroneous judgment of the synchronous time. Therefore, in a Chirp spread spectrum communication system receiver, it is significant to find a method which has strong anti-interference capability and can solve the problem of synchronous misjudgment caused by sampling errors of integral multiple symbol periods.
Disclosure of Invention
The invention relates to a Chirp spread spectrum communication system receiver time synchronization system with strong anti-interference capability.
The invention further aims to provide a time synchronization method for a Chirp spread spectrum communication system receiver, which has low algorithm complexity and high timing precision.
In order to achieve the technical effects, the technical scheme of the invention is as follows:
a time synchronization system of a Chirp spread spectrum communication system receiver comprises a signal-to-noise ratio enhancement module, a combined Chirp modulation module, a peak value searching module and a judgment module; the signal-to-noise ratio enhancing module comprises a modulus obtaining module, a gain obtaining module, a delayer and a combination module, wherein the modulus obtaining module eliminates phase difference between symbols, and the gain obtaining module strengthens useful signals; the combined spread spectrum modulation module uses the combined Chirp signal to perform spread spectrum modulation; after obtaining the signal which is modulated by the combined spread spectrum, received by the matched filtering and enhanced by the signal-to-noise ratio, the searching of the narrow-band pulse peak value after the matched filtering is reduced to a symbol period through a noise threshold value set in a judgment module, and the peak value searching module captures the moment of the peak value in the symbol period to realize time synchronization.
Further, the combined Chirp modulation module multiplies M mapping symbols with M different Chirp spread spectrum signals respectively to realize spread spectrum; at the receiving end, the corresponding matched filter is used to carry out pulse compression on the received signals after the spread spectrum, and then the M de-spread signals are sent to a de-mapper to obtain the original sending data.
Preferably, the value of M is 4.
Furthermore, the signal-to-noise ratio enhancement module eliminates phase difference by performing a modulus operation on the narrow-band compressed pulse after passing through the matched filter, so that a useful signal in one symbol period has a similar waveform, and then the feedback module enhances the signal to suppress interference noise.
A time synchronization method for a Chirp spread spectrum communication system receiver comprises the following steps:
s1: performing a modulus operation on the narrow-band compressed pulse output after the matched filtering, and reinforcing the signal after the modulus operation through a feedback link;
s2: enabling each period symbol to have N sampling points, and respectively carrying out delay processing on 0, N, 2N and 3N sampling points on the received digital baseband signal;
s3: the delayed digital baseband signal is divided through a corresponding matched filter and then sent into a decision module;
s4: judging a signal entering a judgment module to obtain a judged output signal, namely a symbol used for peak value searching;
s5: performing modulus operation on the judged signals, eliminating the influence caused by symbol phase difference, and then combining the signals;
s6: the received digital baseband signal of S2 is used again, the received baseband signal is subjected to modulus operation, 1 sampling point is added in the delay, and signals of 4N sampling points are subtracted in the delay for combination;
s7: respectively delaying the signals in the S6 by 0, N, 2N and 3N sampling points, and then carrying out merging operation;
s8: performing normalization processing by dividing the modulus of the signal obtained in the step S5 by the signal combined in the step S7 to obtain a decision variable;
s9: introducing timing measurement through a decision variable of S8 for measuring the synchronization precision of the time synchronization algorithm;
s10: the peak value searching module searches the peak value in the symbol output after passing through the judging module, and the time corresponding to the peak value is the synchronization time.
Compared with the prior art, the technical scheme of the invention has the beneficial effects that:
the signal-to-noise ratio enhancing module comprises a modulus obtaining module, a gain obtaining module, a delayer and a combining module, wherein the modulus obtaining module eliminates phase difference between symbols, and the gain obtaining module strengthens useful signals; the combined spread spectrum modulation module uses the combined Chirp signal to perform spread spectrum modulation; after obtaining the signal which is modulated by the combined spread spectrum, received by the matched filtering and enhanced by the signal-to-noise ratio, the searching of the narrow-band pulse after the matched filtering is reduced to a symbol period through a noise threshold value set in the judging module, and the peak value searching module captures the moment of the peak value in the symbol period to realize time synchronization. The invention solves the problem of misjudgment of the synchronization time caused by integral multiple symbol periods of difference between the actual synchronization and the ideal synchronization by adding the judgment module in the synchronization module, and improves the timing precision. Meanwhile, the complexity of the algorithm is reduced due to the reduction of the synchronous time searching range.
Drawings
Fig. 1 is a block diagram of a combined Chirp spread spectrum modulation system;
fig. 2 is a synchronization module in a Chirp receiver;
FIG. 3 is a time-frequency relationship diagram of the combined Chirp signal;
FIG. 4 is a CSS communication system parameter diagram;
FIG. 5 is a diagram of a decision block in a peak search method;
FIG. 6 is a block diagram of an improved interference suppression time synchronization algorithm;
FIG. 7 is a diagram of hardware resource comparison for different algorithms;
fig. 8 is a timing metric comparison of the synchronization algorithm.
Detailed Description
The drawings are for illustrative purposes only and are not to be construed as limiting the patent;
for the purpose of better illustrating the embodiments, certain features of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product;
it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.
The technical solution of the present invention is further described below with reference to the accompanying drawings and examples.
Examples
The invention improves the time synchronization method of the Chirp spread spectrum system receiver, mainly adds a judgment module on a peak value searching method, and reduces the algorithm complexity. In addition, a combined spread spectrum modulation and signal-to-noise ratio enhancement module is also involved.
Unlike spread spectrum modulation methods, such as binary quadrature keying (BOK) and Direct Modulation (DM), which are commonly used in spread spectrum modulation, the present invention uses a combined spread spectrum signal for modulation. The idea of combined spreading is to multiply M mapping symbols with M different Chirp spread spectrum signals respectively to realize spreading. At the receiving end, the corresponding matched filter is used for carrying out pulse compression on the received signals after the spread spectrum is carried out, then M despread signals are sent to a demapper to obtain original sending data, the system link capacity is increased, the power efficiency is improved, a combined Chirp spread spectrum modulation system block diagram is shown in figure 1, and the value of M in the invention is 4.
The signal-to-noise ratio enhancing module eliminates phase difference by carrying out modulus operation on the narrow-band compressed pulse after passing through the matched filter, so that useful signals in a symbol period have similar waveforms, and then the feedback module is used for enhancing the signals, thereby achieving the purpose of suppressing interference noise.
The decision module is based on the idea that a signal is irrelevant to noise, and a noise threshold is set, so that when a sampling value obtained by integrating the signal with the noise in a synchronous symbol is smaller than the noise threshold, the sampling value is set to be zero, and the search range of a peak value search method is reduced to a symbol period. For L symbols, the traditional interference suppression synchronization algorithm needs to perform L multiplied by N times of comparison, the synchronization algorithm with the added judgment module only needs to perform L + N times of comparison on the judgment module, and under the condition of larger number of symbols, less hardware resources are consumed, and the complexity is also reduced.
The method comprises the following specific steps:
s1: signal-to-noise ratio enhancement module
S1.1, performing modulus operation on the narrow-band compressed pulse output after matched filtering;
and S1.2, the signals after modulus extraction are enhanced through a feedback link.
S2: step of decision module
S2.1, assuming that each periodic symbol has N sampling points, respectively carrying out delay processing on the received digital baseband signal by 0, N, 2N and 3N sampling points;
s2.2, the digital baseband signals after the time delay processing respectively pass through corresponding matched filters and then are sent into a judgment module;
s2.3, judging the signal entering the judgment module to obtain a judged output signal, namely a signal for peak value searching;
s2.4, performing modulus operation on the judged signals, eliminating the influence caused by symbol phase difference, and then combining the signals;
s2.5, the digital baseband signal received in the S2.1 is reused, the received baseband signal is subjected to modulus operation, 1 sampling point is added in a delaying way, and signals of 4N sampling points are subtracted in a delaying way for combination;
s2.6, similarly to the step 2.1, delaying the signals in the S2.5 by 0, N, 2N and 3N sampling points respectively, and then carrying out merging operation;
and S2.7, performing normalization processing by dividing the signal obtained in S2.4 by the signal combined in S2.6 in a modulus mode, and obtaining a decision variable.
The complete system for Chirp spread spectrum communication consists of a transmitter, a channel and a receiver. The specific steps of the system flow are as follows:
s3: the binary data is converted into complex value data after the parallel-serial conversion, the coding, the serial-parallel conversion and the QPSK modulation sequentially through a splitter (1: 2).
S4: and carrying out differential modulation on the complex value data after QPSK modulation, namely multiplying the current QPSK constellation point by the QPSK constellation point delayed by 3 symbol periods.
S5: the modulation of the combined Chirp signal is achieved by multiplying the complex symbols obtained in S4 with the corresponding spreading function in the combined Chirp signal.
S6: and pulse shaping operation is carried out on the signal after spread spectrum modulation, so that out-of-band leakage can be well inhibited, and intersymbol interference can be prevented.
S7: the digital signals are converted into analog signals through D/A conversion, and radio frequency modulation is realized through up-conversion, so that the signals can be transmitted through an antenna. After the signal is transmitted through a channel, the signal is received through a receiving end antenna, and then the digital baseband signal is obtained through down-conversion and A/D conversion.
S8: the received baseband signal is synchronized, which involves the steps of S1 and S2, and the position of the synchronization module in the Chirp receiver is shown in fig. 2.
S9: the synchronized signals are subjected to signal detection, differential demodulation, parallel-serial conversion, decoding, serial-parallel conversion and combiner to recover binary data.
Combining spread spectrum signals
The combined spread spectrum signal used by the invention contains 4 sub-Chirp signals, the sub-Chirp signals have the same signal bandwidth and code element period, the used frequency modulation slopes have two types, and the inverse number is taken for the slopes to obtain the other two types of frequencies, which is beneficial to the receiving and the generation of the signals, and the interference in a receiving end matched filter can be reduced when the compressed pulse peak value is up-sampled. The time-frequency relationship of the combined spread spectrum signal is shown in fig. 3.
The Chirp signal in one symbol period is described as follows:
Figure BDA0001454612260000061
f0is the Chirp signal center frequency, A is the amplitude of the signal, θ0Is the initial phase, T is the symbol period and μ is the chirp rate. μ T is the bandwidth that the signal "sweeps" through during the symbol period T.
At the receiving end, the impulse response h (t) of the matched filter of the Chirp signal is the inverse conjugate of the signal s (t), h (t) ks (-t), k is the gain of the matched filter, k represents the conjugate operation, and the output after matched filtering is y (t):
Figure BDA0001454612260000062
combining Chirp signals S0(t) is defined as:
Figure BDA0001454612260000063
Tn,k＝(K+1)Tsub+nTchrip(4)
in equations (3) and (4), n is a serial number of a combined Chirp signal to be transmitted, k ═ 0,1,2,3 is a sub Chirp index,
Figure BDA0001454612260000064
for complex symbols after mapping, wkξ for the central angular frequency of the k-th sub-ChirpkIs the sign of the slope of the angular frequency, Tn,kStarting time, T, for generation of sub-Chirp signalchripIs the average duration, T, of the combined Chirp signalsubThe duration of the sub-Chirp.
In the present process, μ ═ 2 pi × 7.1358 × 1012rad/s2，TsubThe specific values of the parameters of each sub-spread spectrum signal of 1.1875us are shown in fig. 4.
Signal-to-noise ratio enhancement
Assuming that the channel is stable in L symbol periods, after L consecutive symbols are pulse compressed, the useful signal is enhanced by r since there is strong correlation between the useful signali(t), i ═ {0,1, …, L-1} represents the i-th useful signal after pulse compression, r0(t)＝r1(t)＝…＝rL-1The useful signal portion after L iterations is r (t) ═ 1+ α2+α3+…+αL-1)r0(t) the corresponding noise is passed through a matched filter and is applied by ni(t), i ═ {0,1, …, L-1}, noise zero mean, variance σ2The white gaussian noise (g) is not correlated with the noise, so after L iterations, the value of n (t) is:
N(t)＝αL-1n0(t)+αL-2n1(t)+…+nL-1(t) (5)
n (t) has a mean of zero and a variance of (1+ α)2+α3+…+αL-1)2The gain of the useful signal energy is:
r(t)＝(1+α2+α4+…+α2(L-1))σ2(6)
the signal-to-noise ratio after L iterations is:
Figure BDA0001454612260000071
when α < 0 and L is infinite,
Figure BDA0001454612260000072
i.e., α approaches 1, the greater the signal-to-noise ratio, the greater the T of the combined signal after matched filteringp(d) The signal may be represented as:
Figure BDA0001454612260000073
in the above formula, Tp(d) For the d-th output value of the p-th matched filter, p ═ {0,1,2,3}, rxFor received baseband signals, mp,nThe coefficient is the nth coefficient of the pth filter, N is the number of sampling points of a sub-Chirp signal, d is the time coefficient of the starting point of a window formed by N sampling points, L is 4 in the scheme, and the signal combination value after passing through four matched filters is p (d):
Figure BDA0001454612260000074
according to the normalization processing of the signals after the matching filtering in the step 2.7, the decision variable can be obtained
Figure BDA0001454612260000081
Decision module structure
The internal structure of the decision module is shown in fig. 5, and L data symbols are sent to the decision device and compared with the noise threshold V. A block diagram of the improved interference suppression time synchronization algorithm is shown in fig. 6. The signal-to-noise ratio enhancing unit comprises a module for taking a module, feeding back, delaying, adding, a signal-to-noise ratio enhancing unit and a judging module for the received baseband signals, and a time synchronization module for forming the CSS system is searched by a peak value.
In order to verify the effect of the invention on time synchronization, corresponding simulation comparison is carried out with the traditional interference suppression synchronization algorithm, and the synchronization algorithm for suppressing the interference for comparison has two algorithms, namely an algorithm A and an algorithm B. The quality of the scheme effect adopts timing measurement as a judgment standard, the timing measurement is defined as a square value of a decision variable, and the larger the timing measurement value is, the better the effect is. The comparison of the hardware resources of the present invention with the other two interference suppression algorithms is shown in fig. 7, and the relationship between the timing metric and the signal-to-noise ratio is shown in fig. 8.
In fig. 7, because complex conjugate matching is adopted, 8 matched filters are required for all three algorithms, and compared with the other two algorithms, the algorithm of the invention has more comparators but does not need multipliers. Therefore, the synchronization algorithm provided by the invention is superior to the other two interference suppression algorithms in terms of using hardware resources and timing measurement through corresponding required hardware resources and simulation.
The same or similar reference numerals correspond to the same or similar parts;
the positional relationships depicted in the drawings are for illustrative purposes only and are not to be construed as limiting the present patent;
it should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

Claims (4)

1. A Chirp spread spectrum communication system receiver time synchronization system is characterized by comprising a signal-to-noise ratio enhancement module, a combined Chirp modulation module, a peak value searching module and a judgment module; the signal-to-noise ratio enhancing module comprises modulus taking, gain obtaining, time delay and combination, wherein the modulus taking eliminates the phase difference between symbols, and the gain obtaining strengthens useful signals; the combined spread spectrum modulation module uses the combined Chirp signal to perform spread spectrum modulation; after obtaining a signal which is subjected to combined spread spectrum modulation, matched filtering reception and signal-to-noise ratio enhancement, searching and reducing the peak value of the narrowband pulse subjected to matched filtering to a symbol period through a noise threshold value set in a judgment module, and realizing time synchronization at the moment when the peak value is captured in the symbol period by a peak value searching module;
the combined Chirp modulation module multiplies M mapping symbols with M different Chirp spread spectrum signals respectively to realize spread spectrum; at the receiving end, the corresponding matched filter is used to carry out pulse compression on the received signals after the spread spectrum, and then the M de-spread signals are sent to a de-mapper to obtain the original sending data.
2. The receiver time synchronization system of a Chirp spread spectrum communication system according to claim 1, wherein the value of M is 4.
3. The receiver time synchronization system of a Chirp spread spectrum communication system according to claim 2, wherein the snr enhancement module removes the phase difference by performing a modulo operation on the narrow band compressed pulse after passing through the matched filter, so that the useful signal in one symbol period has a similar waveform, and then performs a signal enhancement by the feedback module to achieve interference noise suppression.
4. A method for synchronizing a receiver time synchronization system of a Chirp spread spectrum communication system as set forth in claim 1, comprising the steps of:
s1: performing a modulus operation on the narrow-band compressed pulse output after the matched filtering, and enhancing the signal through a feedback link after the modulus operation;
s2: enabling each period symbol to have N sampling points, and respectively carrying out delay processing on 0, N, 2N and 3N sampling points on the received digital baseband signal;
s3: the delayed digital baseband signals are respectively passed through corresponding matched filters and then sent into a decision module;
s4: judging a signal entering a judgment module to obtain a judged output signal, namely a symbol used for peak value searching;
s5: performing modulus operation on the judged signals, eliminating the influence caused by symbol phase difference, and then combining the signals;
s6: the digital baseband signal received in the step S2 is used again, the received baseband signal is subjected to modulus operation, 1 sampling point is added in the delay, and signals of 4N sampling points are subtracted in the delay for combination;
s7: respectively delaying the signals in the S6 by 0, N, 2N and 3N sampling points, and then carrying out merging operation;
s8: performing normalization processing by dividing the modulus of the signal obtained in the step S5 by the signal combined in the step S7 to obtain a decision variable;
s9: introducing a timing metric for representing the synchronization precision of the time synchronization algorithm through a decision variable of S8;
s10: and the peak value searching module searches the peak value of the symbol output by the judging module, and the time corresponding to the peak value is the synchronization time.
CN201711060079.7A 2017-11-01 2017-11-01 Chirp spread spectrum communication system receiver time synchronization system and method Active CN107769816B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201711060079.7A CN107769816B (en) 2017-11-01 2017-11-01 Chirp spread spectrum communication system receiver time synchronization system and method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201711060079.7A CN107769816B (en) 2017-11-01 2017-11-01 Chirp spread spectrum communication system receiver time synchronization system and method

Publications (2)

Publication Number Publication Date
CN107769816A CN107769816A (en) 2018-03-06
CN107769816B true CN107769816B (en) 2020-10-09

Family

ID=61272015

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201711060079.7A Active CN107769816B (en) 2017-11-01 2017-11-01 Chirp spread spectrum communication system receiver time synchronization system and method

Country Status (1)

Country Link
CN (1) CN107769816B (en)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111953624A (en) * 2019-05-17 2020-11-17 中兴通讯股份有限公司 Echo time delay estimation method and device
CN111478754B (en) * 2019-09-20 2023-03-21 上海磐启微电子有限公司 Signal modulation method
CN112134820B (en) * 2020-08-24 2022-01-14 北京智芯微电子科技有限公司 Modulation method, modulator, demodulation method, demodulator, communication method and system
CN112332885B (en) * 2020-11-10 2022-05-24 普联技术有限公司 Periodic signal peak searching method, device, equipment and readable storage medium
CN112671680B (en) * 2021-01-20 2023-01-31 哈尔滨工业大学 LoRa demodulation method based on multiple bandwidth sampling for improving error code performance
CN114001892B (en) * 2021-10-28 2023-12-05 北京机电工程研究所 Time synchronization method between free jet test measurement systems
CN115842567B (en) * 2023-02-22 2023-05-02 四川思凌科微电子有限公司 Dynamic threshold synchronization method and device based on CHIRP communication

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BRPI9909023B1 (en) * 1998-03-23 2017-03-28 Samsung Electronics Co Ltd power control device and method of controlling a common reverse link channel in a cdma communication system
CN101252566B (en) * 2008-04-14 2012-04-25 哈尔滨工业大学 Method and apparatus for generating and receiving frequency domain direct enlarging - fractional number field frequency-hopping mixing signal
US8165172B2 (en) * 2008-06-06 2012-04-24 Maxim Integrated Products, Inc. Robust wideband symbol and frame synchronizer for power-line communication
EP2182349A1 (en) * 2008-10-28 2010-05-05 Axsensor AB Method for determining the starting instant of a periodically oscillating signal response
CN104092642B (en) * 2014-07-30 2017-07-28 东南大学 A kind of carrier phase synchronization method and device being used in non-coherent demodulation circuit
CN104199016B (en) * 2014-09-12 2016-09-07 四川九洲电器集团有限责任公司 Wireless distance finding method based on CSS technology and CSS wireless terminal

Also Published As

Publication number Publication date
CN107769816A (en) 2018-03-06

Similar Documents

Publication Publication Date Title
CN107769816B (en) Chirp spread spectrum communication system receiver time synchronization system and method
Kim et al. An efficient frequency offset estimator for OFDM systems and its performance characteristics
CN108365945B (en) Differential chaotic shift keying modem and method based on two-way index modulation
EP3329601B1 (en) Method and apparatus for communicating data in a digital chaos cooperative network
CN101056294B (en) Super broad band communication system and method for using in super broad band communication
WO2019153591A1 (en) Phase splitting differential chaos shift keying communication method based on hybrid system
CN102739590A (en) CP-EBPSK communication system for pseudorandom sequence phase modulation and communication method thereof
WO2022213764A1 (en) M-fsk modulation-based receiver and reception method therefor
KR20070024617A (en) A transmitter and receiver for ultra-wideband ofdm signals employing a low-complexity cdma layer for bandwidth expansion
CN104836773A (en) Bipolar binary shift pulse keying modulation and demodulation method
CN102025669A (en) Short-wave data transmission method based on dual multisystem quasi-orthogonal spread-spectrum composite phase modulation
CN108696467B (en) Noise suppression method for improving reliability of differential chaos keying communication system
WO2015176597A1 (en) Ebpsk-based communication method and system
CN111901269A (en) Gaussian frequency shift keying modulation method, device and system with variable modulation index
KR101254210B1 (en) Offset phase rotation shift keying modulation apparatus and method, phase silence rotation shift keying modulation apparatus and method, and phase silence rotation shift keying demodulation apparatus and method
CN102332937B (en) OPPM-UWB (overlapping pulse position modulation-ultra wide band) communication method on basis of time reversal technology
CN112994833B (en) WFRFT-based transparent transponder user cooperation physical layer secure transmission method
CN101741405B (en) Receiving method suitable for impulse radio ultra wide band system
CN111431833B (en) Underwater current field communication method based on serial combination
CN110049545B (en) Synchronization method of G bit-level broadband received signal
Ying et al. Block-coded modulation and noncoherent detection for impulse radio UWB
CN111868545B (en) Satellite communication navigation signal generation method and device and satellite communication navigation signal receiving method and device
An et al. A turbo coded LoRa-index modulation scheme for IoT communication
CN101945068A (en) Detection method of receiver of single-carrier frequency domain equalizing system with low transmission power
Erseghe A low-complexity impulse radio receiver based upon Gaussian mixtures

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant