CN110933011A - High-resolution blind scanning method for WFRFT (WFRFT) signals - Google Patents

High-resolution blind scanning method for WFRFT (WFRFT) signals Download PDF

Info

Publication number
CN110933011A
CN110933011A CN201911263420.8A CN201911263420A CN110933011A CN 110933011 A CN110933011 A CN 110933011A CN 201911263420 A CN201911263420 A CN 201911263420A CN 110933011 A CN110933011 A CN 110933011A
Authority
CN
China
Prior art keywords
channel
modulation order
wfrft
calculating
data
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.)
Granted
Application number
CN201911263420.8A
Other languages
Chinese (zh)
Other versions
CN110933011B (en
Inventor
刘芳
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.)
Shenyang Ligong University
Original Assignee
Shenyang Ligong 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 Shenyang Ligong University filed Critical Shenyang Ligong University
Priority to CN201911263420.8A priority Critical patent/CN110933011B/en
Publication of CN110933011A publication Critical patent/CN110933011A/en
Application granted granted Critical
Publication of CN110933011B publication Critical patent/CN110933011B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/2601—Multicarrier modulation systems
    • H04L27/2626—Arrangements specific to the transmitter only
    • H04L27/2627—Modulators
    • H04L27/2628—Inverse Fourier transform modulators, e.g. inverse fast Fourier transform [IFFT] or inverse discrete Fourier transform [IDFT] modulators
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/26—Systems using multi-frequency codes
    • H04L27/2601—Multicarrier modulation systems
    • H04L27/2647—Arrangements specific to the receiver only
    • H04L27/2649—Demodulators
    • H04L27/265—Fourier transform demodulators, e.g. fast Fourier transform [FFT] or discrete Fourier transform [DFT] demodulators

Landscapes

  • Physics & Mathematics (AREA)
  • Discrete Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Mathematical Physics (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Digital Transmission Methods That Use Modulated Carrier Waves (AREA)

Abstract

A high resolution blind scanning method of WFRFT signal belongs to the technical field of receiving method of WFRFT communication system, the method comprises establishing rule relation of modulation order error and error rate under theoretical condition, determining minimum main value window; setting a left modulation order and a right modulation order in each channel, further performing WFRFT inverse processing of two branches on a received signal by each channel, calculating a peak-to-average ratio to obtain a theoretical boundary value, calculating a mapping channel, and further calculating a demodulation order corresponding to the channel; calculating an estimated modulation order; and performing WFRFT inverse processing by using the estimated modulation order and the received signal, and obtaining demodulation data. The invention solves the scanning problem under the unknown modulation order condition and the fuzzy modulation order condition in the severe environment and the fuzzy resolution problem of the successful channel in the multi-channel scanning.

Description

High-resolution blind scanning method for WFRFT (WFRFT) signals
Technical Field
The invention belongs to the technical field of receiving methods of WFRFT communication systems, and particularly relates to a blind scanning receiving method under the condition of unknown modulation orders.
Background
Weighted Fractional Fourier Transform (WFRFT) is a Transform domain signal processing means in wireless communication systems. The modulation order (parameter) in the general WFRFT system is known only to own users and is unknown to other users. Therefore, considering the uncertain modulation order under unknown conditions or severe environment conditions, the setting of the demodulation order at the receiving end cannot meet the requirement of correctly recovering the original data, so blind scanning processing is required. The current scanning methods are all scanning in one period of modulation order at intervals of 0.01, so the scanning times are 400 times, obviously, for a high-speed processor, 400 times of WFRFT inverse processing are not a problem, but how to distinguish exact successful channels from the demodulation results of 400 channels becomes a difficult problem. If the successful channel cannot be distinguished, the subsequent analysis, analysis and other processing are required to be carried out on the 400 groups of data all the time, and the channel which is real data cannot be distinguished after the analysis. If 400 channels of data processing are required for each cycle, a great complexity and ambiguity resolution are involved for a continuous multi-cycle or real-time data transmission system. Therefore, the blind scanning method with high resolution capability is researched to become the key of the WFRFT signal processing field.
Disclosure of Invention
The invention provides a high-resolution blind scanning method of a WFRFT signal, which discusses the shunt relevant characteristics of a left modulation order and a right modulation order by establishing a rule between a modulation order error and a theoretical bit error rate, gives a rectangular relevant interval, obtains an estimated modulation order by utilizing a rectangular relevant interval boundary and a relevant mapping channel, and further recovers real data to achieve the aim of high-resolution blind scanning.
The technical scheme is as follows:
in a high-resolution blind scanning method of WFRFT signals, firstly, a modulation order error and bit error rate rule relation under a theoretical condition is established, and a minimum main value window is determined.
Then, a multi-channel demodulation order is established in a main value window, a left modulation order and a right modulation order are set in each channel, each channel further carries out WFRFT inverse processing of two branches on the received signal, correlation operation is carried out by using the inverse processing results of the two branches in each channel, and the peak-to-average ratio is calculated.
Further, a rectangular correlation interval is established by using the theoretical correlation degree, and a theoretical boundary value is obtained.
And then, calculating a mapping channel by using the peak-to-average ratios of the plurality of channels, and further calculating a demodulation order corresponding to the channel.
Next, an estimated modulation order is calculated using the above calculation result.
And finally, performing WFRFT inverse processing by using the estimated modulation order and the received signal, and obtaining demodulation data.
Further, a method for high resolution blind scanning of WFRFT signal according to claim 1 is specifically as follows:
establishing a regular relation between modulation order error delta β and an error rate under a theoretical condition, setting a minimum main value window K to be 2, and setting a step amount to be lambda to be 0.01;
in a minimum principal value period, namely 0-2 intervals, carrying out multichannel scanning by taking lambda as a stepping quantity, wherein the scanning upper limit is N:
Figure BDA0002312203310000031
define demodulation order set βiFormula (7), wherein i ∈ [1N ]]，
βi＝i·λ (7)
Assuming that the estimated modulation order is α ', the error between the demodulation order of each channel and α' is:
Δβi＝α'-βi(8)
β will be mixediIs subjected to periodic continuation to obtain
Figure BDA0002312203310000032
Then, the reverse rotation and the translation are carried out to obtain
Figure BDA0002312203310000033
And
Figure BDA0002312203310000034
at each passage βiOn the basis, the right modulation order β is carried outiRLeft modulation order βiLAnd (3) calculating:
Figure BDA0002312203310000035
Figure BDA0002312203310000036
using two branches β per channeliRAnd βiLPerforming WFRFT with the received signals S (n), respectivelyAnd (3) reverse treatment:
Figure BDA0002312203310000037
Figure BDA0002312203310000038
two-branch inverse processing result S in each channeliR(n) and SiL(n) performing correlation operation to obtain correlation result C of each channeli(n), wherein fft (-), ifft (-) are fast fourier transform and inverse transform processing functions;
Figure BDA0002312203310000041
by Ci(n) calculating the Peak-to-average ratio PiWhere max (·) is a maximum calculation function;
Figure BDA0002312203310000042
Figure BDA0002312203310000043
Figure BDA0002312203310000044
ΔβRto the right boundary of the rectangular correlation interval, Δ βLIs the left boundary of the rectangular correlation interval;
using peak-to-average ratio P of N channelsiComparing with a threshold G, and further calculating to obtain a continuous sequence R (j), wherein mod (·) is a modular operation function;
Figure BDA0002312203310000045
and (3) performing minimum value calculation on the continuous sequence R (j) by using a minimum value calculation function min (·), and performing minimum periodic processing to obtain a mapping channel H corresponding to a rectangular correlation interval:
H＝mod(min[R(j)],N) (18)
using the mapping channel H, the demodulation order β corresponding to the channel is calculatedH：
Figure BDA0002312203310000051
By βHAnd the right boundary Δ β of the rectangular intervalRAnd, in conjunction with equation (8), an estimated modulation order α' may be calculated:
Figure BDA0002312203310000052
wherein m is an integer and is more than or equal to 0, and m is selected to ensure that α' is the minimum positive value in [04 ];
using α' obtained by estimation and the received signal S (n) to perform WFRFT inverse processing:
Figure BDA0002312203310000053
calculating to obtain data D ' (n) after WFRFT inverse processing as a formula (22), if the modulation order α of the transmitting end is in a range of 0-2, the demodulated data D ' (n) is real data x (n), and if the modulation order α of the transmitting end is in a range of 2-4, the demodulated data D ' (n) is inverted data x (-n) of the real data;
Figure BDA0002312203310000054
the data D ' (n) and the data D ' (-n) obtained by inverting the data D ' (n) are outputted simultaneously.
The invention has the advantages and effects that:
a high-resolution blind scanning method for WFRFT signals aims to solve the problems of scanning under unknown modulation order conditions and fuzzy modulation order conditions in severe environments and the problem of fuzzy resolution of successful channels in the conventional multi-channel scanning. A high-resolution blind scanning method for WFRFT signals not only can not increase the complexity of a system, but also can accurately estimate the modulation order and correctly output the original data, thereby achieving the purpose of high-resolution blind scanning. The blind scanning method is not only suitable for a 4-WFRFT communication system, but also suitable for a multi-item WFRFT communication system, and is compatible with the conditions of fixed single parameters and variable single parameters.
Drawings
Fig. 1 is a diagram of the relationship between modulation order error and bit error rate rule in the high-resolution blind scanning method of WFRFT signal of the present invention.
Fig. 2 is a diagram of an implementation scheme of a high-resolution blind scanning method for a WFRFT signal according to the present invention.
Detailed Description
The invention is further explained below with reference to the figures and the examples.
Let the data information to be transmitted in the digital communication system be x (n), and the length of data transmitted per period be L, for which n belongs to [1L ]. Defining 4 kinds of state functions of X (n), X (-n) and X (-n) as 0,1,2 and 3 times Fourier transform results of X (n), respectively. Since all the multiple WFRFT systems can be converted into corresponding 4 WFRFT systems, the implementation of the 4-WFRFT system can be universally applied to the multiple WFRFT systems.
At the transmitting end of the communication, the modulation order (parameter) of the WFRFT process is defined α, and the weighting coefficient ω can be established by αl(α) (l is 0,1,2,3), ω is determined as shown in formula (1)lThe modulation order α of (α) is 4 cycles as in the fourier transform, for which [04) is set as a main cycle, and all modulation orders can be equivalent to one [04) cycle.
Figure BDA0002312203310000061
Using established omegal(α) the data x (n) to be transmitted is processed with WFRFT of α order, as shown in formula (2), wherein Fα(. cndot.) is a WFRFT processing function of order α.
S(n)＝Fα(x(n))＝ω0(α)x(n)+ω1(α)X(n)+ω2(α)x(-n)+ω3(α)X(-n) (2)
If the demodulation order of the receiving end is β, the WFRFT inverse transform of β order is carried out on the received signal S (n):
Figure BDA0002312203310000071
setting:
Δβ＝α-β (4)
it can be seen that equation (3) can be written as equation (5) only when Δ β → 0, i.e. β ═ α, which indicates that the original data x (n) can be correctly recovered.
SΔ(n)＝FΔβ(x(n))≈x(n) (5)
For this reason, considering the uncertain modulation order under unknown conditions or severe environment conditions, the setting of the receiving end β cannot satisfy the condition of β ═ α, so that the modulation order β needs to be scanned blindly, so that Δ β → 0 can receive the data x (n) correctly, and a high-resolution blind scanning method for the WFRFT signal is proposed.
In a high-resolution blind scanning method for a WFRFT signal, a theoretical modulation order error Δ β is first established in a regular relationship with an error rate, and as shown in fig. 1, as Δ β increases, the error rate does not tend to increase linearly, but changes cyclically, and the cycle period also tends to be 4, and in one cycle, the minimum main value window K is set to 2, and then the step amount is set to λ 0.01, taking Δ β as a symmetry axis to be symmetric.
Based on this, in a minimum principal value period, namely 0-2 intervals, with lambda as the stepping quantity, multi-channel scanning is carried out, the scanning upper limit is N:
Figure BDA0002312203310000081
second, define the solutionOrder-adjusting group βiFormula (7), wherein i ∈ [1N ]]There are 201 channels in total.
βi＝i·λ (7)
Further, assuming that the estimated modulation order is α ', the error between the demodulation order of each channel and α' is:
Δβi＝α'-βi(8)
further, β will be addediIs subjected to periodic continuation to obtain
Figure BDA0002312203310000084
Then, the reverse rotation and the translation are carried out to obtain
Figure BDA0002312203310000085
And
Figure BDA0002312203310000086
as can be seen from FIG. 1, the following steps are carried out
Figure BDA0002312203310000087
And a variation of α that is,
Figure BDA0002312203310000088
and
Figure BDA0002312203310000089
has the lowest correlation characteristic, for which β exists at each channeliOn the basis, the right modulation order β is carried outiRLeft modulation order βiLAnd (3) calculating:
Figure BDA0002312203310000082
Figure BDA0002312203310000083
in channel 201, two branches β for each channel are utilizediRAnd βiLPerforming WFRFT inverse processing on the received signals S (n):
Figure BDA0002312203310000091
Figure BDA0002312203310000092
then, the two-branch inverse processing result S in each channeliR(n) and SiL(n) performing correlation operation to obtain correlation result C of each channeli(n), where fft (-), ifft (-) are fast fourier transform and inverse transform processing functions.
Figure BDA0002312203310000093
Further, use of Ci(n) calculating the Peak-to-average ratio PiWhere max (·) is a maximum calculation function.
Figure BDA0002312203310000094
As can be seen in fig. 1, within the main value window of α ═ 0, following βiWhen scanning to
Figure BDA0002312203310000095
In the interval, the interval with the maximum two-branch correlation degree appears, the interval presents a rectangular distribution and is called a rectangular correlation interval for this reason, the rectangular correlation interval range related to delta β can be obtained through calculation, as shown in formulas (15) and (16), delta βRTo the right boundary of the rectangular correlation interval, Δ βLThe left border of the rectangular correlation interval.
Figure BDA0002312203310000101
Figure BDA0002312203310000102
As can be seen in FIG. 1, a shift with the main value window may be equivalent to a change in the α 'value, regardless of the α' valueThe values, within each shifted main value window, exhibit a rectangular correlation interval with respect to Δ β and the peak, and the right boundary Δ βRAnd a left boundary Δ βLThe results of equations (15) and (16) are always satisfied.
Then, the peak-to-average ratio P of N channels is usediAnd comparing with a threshold G, and further calculating to obtain a continuous sequence R (j), wherein mod (-) is a modulus operation function.
Figure BDA0002312203310000103
And then, performing minimum value calculation on the continuous sequence R (j) by using a minimum value calculation function min (-) and performing minimum periodic processing to obtain a mapping channel H corresponding to the rectangular correlation interval:
H＝mod(min[R(j)],N) (18)
using the mapping channel H, the demodulation order β corresponding to the channel is calculatedH：
Figure BDA0002312203310000104
By βHAnd the right boundary Δ β of the rectangular intervalRAnd, in conjunction with equation (8), an estimated modulation order α' may be calculated:
Figure BDA0002312203310000111
where m is an integer and m is greater than or equal to 0, m is selected such that α' is the smallest positive value within [04 ], since the true modulation order α is 4 cycles, whatever the α value, it can be equivalent to be within [04 ].
Then, WFRFT inverse processing is performed using the estimated α' and the received signal s (n):
Figure BDA0002312203310000112
finally, the data D ' (n) after WFRFT inverse processing is calculated and obtained is formula (22), it can be seen that if the modulation order α of the transmitting end is in the interval of 0-2, the demodulated data D ' (n) is the real data x (n), and if the modulation order α of the transmitting end is in the interval of 2-4, the demodulated data D ' (n) is the inverse data x (-n) of the real data.
Figure BDA0002312203310000113
Because it cannot be determined whether the original modulation order is within 0-2 or within 2-4, the data D ' (n) and the data D ' (-n) after D ' (n) inversion are output simultaneously, and the complexity of 2-path data analysis processing is far better than that of 400-path data analysis processing.
A high-resolution blind scanning method for WFRFT signals carries out modulation order estimation and communication data reception under the condition of unknown modulation order (parameter), so that the same scanning conclusion can be reached no matter whether the modulation order is in a fixed form or a dynamic change form. In addition, since all the WFRFT systems can be converted into corresponding 4-term WFRFT systems, a high-resolution blind scanning method for WFRFT signals is not only suitable for 4-term WFRFT systems, but also suitable for multi-term WFRFT systems.

Claims (2)

1. A high resolution blind scanning method for WFRFT signals is characterized in that: firstly, establishing a regular relation between a modulation order error and an error rate under a theoretical condition, and determining a minimum main value window; establishing a multi-channel demodulation order in a main value window, setting a left modulation order and a right modulation order in each channel, further performing WFRFT inverse processing of two branches on a received signal by each channel, performing correlation operation by using the inverse processing results of the two branches in each channel, and calculating a peak-to-average ratio; establishing a rectangular correlation interval by using the theoretical correlation degree, and obtaining a theoretical boundary value; calculating a mapping channel by using the peak-to-average ratios of a plurality of channels, and further calculating a demodulation order corresponding to the channel; calculating an estimated modulation order by using the calculation result; and performing WFRFT inverse processing by using the estimated modulation order and the received signal, and obtaining demodulation data.
2. The method of claim 1, wherein the method comprises the following steps:
establishing a regular relation between modulation order error delta β and an error rate under a theoretical condition, setting a minimum main value window K to be 2, and setting a step amount to be lambda to be 0.01;
in a minimum principal value period, namely 0-2 intervals, carrying out multichannel scanning by taking lambda as a stepping quantity, wherein the scanning upper limit is N:
Figure FDA0002312203300000011
define demodulation order set βiFormula (7), wherein i ∈ [1N ]]，
βi＝i·λ (7)
Assuming that the estimated modulation order is α ', the error between the demodulation order of each channel and α' is:
Δβi＝α'-βi(8)
β will be mixediIs subjected to periodic continuation to obtain
Figure FDA0002312203300000021
Then, the reverse rotation and the translation are carried out to obtain
Figure FDA0002312203300000022
And
Figure FDA0002312203300000023
at each passage βiOn the basis, the right modulation order β is carried outiRLeft modulation order βiLAnd (3) calculating:
Figure FDA0002312203300000024
Figure FDA0002312203300000025
using two branches β per channeliRAnd βiLPerforming WFRFT inverse processing on the received signals S (n):
Figure FDA0002312203300000026
Figure FDA0002312203300000027
two-branch inverse processing result S in each channeliR(n) and SiL(n) performing correlation operation to obtain correlation result C of each channeli(n), wherein fft (-), ifft (-) are fast fourier transform and inverse transform processing functions;
Figure FDA0002312203300000028
by Ci(n) calculating the Peak-to-average ratio PiWhere max (·) is a maximum calculation function;
Figure FDA0002312203300000031
Figure FDA0002312203300000032
Figure FDA0002312203300000033
ΔβRto the right boundary of the rectangular correlation interval, Δ βLIs the left boundary of the rectangular correlation interval;
using peak-to-average ratio P of N channelsiComparing with a threshold G, and further calculating to obtain a continuous sequence R (j), wherein mod (·) is a modular operation function;
Figure FDA0002312203300000034
and (3) performing minimum value calculation on the continuous sequence R (j) by using a minimum value calculation function min (·), and performing minimum periodic processing to obtain a mapping channel H corresponding to a rectangular correlation interval:
H＝mod(min[R(j)],N) (18)
using the mapping channel H, the demodulation order β corresponding to the channel is calculatedH：
Figure FDA0002312203300000035
By βHAnd the right boundary Δ β of the rectangular intervalRAnd, in conjunction with equation (8), an estimated modulation order α' may be calculated:
Figure FDA0002312203300000041
wherein m is an integer and is more than or equal to 0, and m is selected to ensure that α' is the minimum positive value in [04 ];
using α' obtained by estimation and the received signal S (n) to perform WFRFT inverse processing:
Figure FDA0002312203300000042
calculating to obtain data D ' (n) after WFRFT inverse processing as a formula (22), if the modulation order α of the transmitting end is in a range of 0-2, the demodulated data D ' (n) is real data x (n), and if the modulation order α of the transmitting end is in a range of 2-4, the demodulated data D ' (n) is inverted data x (-n) of the real data;
Figure FDA0002312203300000043
the data D ' (n) and the data D ' (-n) obtained by inverting the data D ' (n) are outputted simultaneously.
CN201911263420.8A 2019-12-11 2019-12-11 High-resolution blind scanning method for WFRFT (WFRFT) signals Active CN110933011B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201911263420.8A CN110933011B (en) 2019-12-11 2019-12-11 High-resolution blind scanning method for WFRFT (WFRFT) signals

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201911263420.8A CN110933011B (en) 2019-12-11 2019-12-11 High-resolution blind scanning method for WFRFT (WFRFT) signals

Publications (2)

Publication Number Publication Date
CN110933011A true CN110933011A (en) 2020-03-27
CN110933011B CN110933011B (en) 2022-06-10

Family

ID=69859723

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201911263420.8A Active CN110933011B (en) 2019-12-11 2019-12-11 High-resolution blind scanning method for WFRFT (WFRFT) signals

Country Status (1)

Country Link
CN (1) CN110933011B (en)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103441822A (en) * 2013-09-16 2013-12-11 哈尔滨工业大学 Signal modulation method based on weighted-type fractional Fourier transform and energy spreading transform
WO2017054632A1 (en) * 2015-09-29 2017-04-06 华为技术有限公司 Signal sending method, signal receiving method, transmitting terminal and receiving terminal
CN107682297A (en) * 2017-09-06 2018-02-09 西北工业大学 A kind of mobile underwater sound communication method
CN108920419A (en) * 2018-06-20 2018-11-30 沈阳理工大学 Scan method is classified based on one-parameter Fractional Fourier inverse transformation

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103441822A (en) * 2013-09-16 2013-12-11 哈尔滨工业大学 Signal modulation method based on weighted-type fractional Fourier transform and energy spreading transform
WO2017054632A1 (en) * 2015-09-29 2017-04-06 华为技术有限公司 Signal sending method, signal receiving method, transmitting terminal and receiving terminal
CN107682297A (en) * 2017-09-06 2018-02-09 西北工业大学 A kind of mobile underwater sound communication method
CN108920419A (en) * 2018-06-20 2018-11-30 沈阳理工大学 Scan method is classified based on one-parameter Fractional Fourier inverse transformation

Also Published As

Publication number Publication date
CN110933011B (en) 2022-06-10

Similar Documents

Publication Publication Date Title
CN1070325C (en) Method and apparatus of estimating channel quality in a receiver
CN1780276B (en) Combined time synchronizing and frequency bias evaluation and evaluating device for orthogonal frequency division duplex system
DE60013129T2 (en) METHOD AND DEVICE FOR OBTAINING SYMBOL ASSAY AND FREQUENCY SYNCHRONIZATION OF AN ORTHOGONAL FREQUENCY MULTIPLEX SIGNAL
CN1221096C (en) Channel estimation method for orthogonal frequency-division multiplexing communication system
CN107154908A (en) The generation method of leading symbol
CN1061186C (en) Demodulator for manchester-coded FM signals
JP2004072724A (en) Method and instrument for measuring sinr for ofdm communication system
CN107682297A (en) A kind of mobile underwater sound communication method
KR20010022578A (en) Method and device for combined measurement of the beginning of a data block and carrier frequency shift in a multicarrier transmission system in f classes
CN101909024B (en) Method and device for estimating maximum Doppler frequency offset
US6249213B1 (en) Method for transmitting information over an alternating current power line through a plurality of frequency orthogonal subchannels
CN1420647A (en) Receiver of quadrature frequency division multiplexing system
CN1209001A (en) Equalizing method and equalizer for OFDM receiver
CN1581741A (en) Sudden signal receiver
CN104836769A (en) Combined timing and frequency synchronization method based on conjugated structure preamble
CN108737317B (en) Generalized mixed carrier frequency-selective channel transmission method
CN108562883A (en) A kind of maximum likelihood distance estimating algorithm of overloading wave radar system
JPH10150428A (en) Receiver employing orthogonal frequency division multiplexing and its timing synchronization method
CN1219021A (en) Method and system for timed retoring and channel estimation in discrete multione modem
CN1224246C (en) Facilitating motion estimation
CN1329786A (en) Synchronization tracking method
CN105162527A (en) Underwater communication hybrid carrier method based on weighted fractional order Fourier transform
CN110933011B (en) High-resolution blind scanning method for WFRFT (WFRFT) signals
DE3750152T2 (en) Data transmission system with correlation receiver.
CN106254289A (en) A kind of frequency offset estimation methods, transmitter, receiver and communication system

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