CN108156108A - A kind of start position of OFDM symbol determines method and apparatus - Google Patents
A kind of start position of OFDM symbol determines method and apparatus Download PDFInfo
- Publication number
- CN108156108A CN108156108A CN201711463206.8A CN201711463206A CN108156108A CN 108156108 A CN108156108 A CN 108156108A CN 201711463206 A CN201711463206 A CN 201711463206A CN 108156108 A CN108156108 A CN 108156108A
- Authority
- CN
- China
- Prior art keywords
- code
- long leading
- start position
- received signal
- sampled point
- 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
Links
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
- H04L27/2647—Arrangements specific to the receiver only
- H04L27/2655—Synchronisation arrangements
- H04L27/2662—Symbol synchronisation
- H04L27/2665—Fine synchronisation, e.g. by positioning the FFT window
Abstract
The invention discloses a kind of start positions of OFDM symbol to determine method and apparatus, for promoting the accuracy that symbol plays point location, improves the network Quality of experience of user.This method includes：Receiving terminal determines the position of the lead code starting point in received signal；The lead code includes long leading code；The K default long leading codes that the receiving terminal includes the received signal with default long leading code set carry out computing cross-correlations, obtain K operation result, and the operation result is used to characterize position of the long leading code in the lead code；The default long leading code set is stored in the receiving terminal, K is the integer not less than 2；The receiving terminal determines the start position of OFDM symbol according to the position and the K operation result of the lead code starting point；Wherein, the start position of the OFDM symbol is identical with the start position of the long leading code.
Description
Technical field
The present invention relates to field of communication technology, more particularly to a kind of Orthogonal Frequency Division Multiplexing (Orthogonal Frequency
Division Multiple, OFDM) symbol start position determines method and apparatus.
Background technology
At present, Orthogonal Frequency Division Multiple Access (Orthogonal Frequency Division MultipleAccess,
OFDMA) in communication system, communication bandwidth is divided into multiple subchannels, multiple subcarriers are included per sub-channels, then with son
Channel distributes to multiple user equipmenies for resource units, can then realize communicate while multiple user equipmenies, and pass through in this way
Orthogonality between subcarrier realizes the high superposed of subcarrier, greatly improves the availability of frequency spectrum, thus, OFDMA leads to
Letter system is widely used.
Due to the technical characterstic of OFDMA, multiple users occupy different subcarriers on frequency domain and communicate, but
It is to send signal simultaneously in time domain, then in the time domain, signal is mutual aliasing.In the communication for needing transmission lead code
In system, lead code is commonly used in carrying out frame starting point positioning, symbol plays point location and offset estimation etc..It synchronizes at present
Method includes two steps, i.e., slightly synchronous (coarse synchronization) (fine synchronous with essence
synchronization).Wherein, it slightly synchronizes delay auto-correlation computation in the time-domain signal for referring to will receive and carrys out getting frame
Point position, essence synchronize the time-domain signal for referring to receive and carry out computing cross-correlation with the lead code that receiving terminal is pre-stored to obtain
Take the start position of OFDM symbol.The start position of OFDM symbol is obtained by following computing cross-correlation formula：
Wherein, zm+qFor the time-domain expression for the baseband signal that receiving terminal receives, pqIt is pre-stored for receiving terminal entire
The signal of the long leading code of system, the length of long leading code are Q, 0≤q≤Q-1,For the conjugation of long leading code that receiving terminal is pre-stored,
Φzp(m) the received signal z obtained to sampling is representedm+qIn q-th of the m+q sampled point and pre-stored long leading code adopt
The conjugation of sampling point carries out computing cross-correlation,Result to cause above-mentioned computing cross-correlation obtains the value of the m of maximum value.Its
In, the corresponding sampled point of value of m is the start position of long leading code, that is, the start position of OFDM symbol.
Frame starting point is used to define the initial position of a wireless signal frame, in the case where frame starting point has determined, into one
Step determines the start position of OFDM symbol, could realize that the accurate of OFDM symbol is defined, and then could carry out subsequent solution in this way
Code operation.The positioning of the start position of OFDM symbol it is possible that three kinds as a result, i.e. preferable, in advance and lag.Such as Fig. 1 institutes
Show, if the start position of the OFDM symbol of positioning is desired result, i.e. the start position of OFDM symbol is just located in one
The start position of the cyclic prefix (Cyclic Prefix, CP) of OFDM symbol, then carry out fast Fourier transform (Fast
Fourier Transformation, FFT) CP can just be removed, obtain the data segment of an OFDM symbol, i.e. in Fig. 1
Shown preferable FFT windows are just fallen on the data segment 1 of OFDM symbol 1.If the start position of the OFDM symbol of positioning carries
Before, since the CP in an OFDM symbol is by the rear N of the data segment in the OFDM symbolsGIWhat a data replicated, also
To say, even if the start position of OFDM symbol of positioning shifts to an earlier date, as long as but the length of of length no more than CP in advance, then
The data that OFDM symbol after FFT transform includes remain complete, also are able to be solved subsequently through certain means
Analysis.If the start position lag of the OFDM symbol of positioning, then the data of the latter OFDM symbol will be introduced, i.e., can caused
Inter-carrier interference (Inter Carrier Interference, ICI) and intersymbol interference (Inter symbol
Interference, ISI), then the data that the OFDM symbols after FFT transform is carried out include are then incomplete, nothings
Method is normally carried out parsing, and can not be normally carried out so as to cause communication process.Therefore, sign synchronization is with detecting whether correctly directly
It is related to the follow-up sequence of operations for being directed to data message, therefore symbol starting point is located in decoding process and is one and closes very much
The step of key.
But in OFDMA system, multiple users send signal simultaneously, the channel undergone due to the signal of multiple users
Decline, transmission power and apart from the position of base station difference, can cause the signal of each user to reach the signal strength of base station and deposit
In difference, arrival time, there is also differences.Current synchronous method is easier to the signal by user when carrying out smart synchronous
Intensity is interfered, and the result of positioning is generally biased towards the stronger user of signal, that is, the symbol starting point positioned is partial to the strong use of signal
The symbol starting point at family, and so that the symbol location of the weak user of signal is inaccurate, and then the signal of the weak user of signal can not solve
Code success, it is bad so as to the network experience of the weaker user of signal.
Invention content
The embodiment of the present invention provides a kind of start position of OFDM symbol and determines method and apparatus, is risen for promoting symbol
The accuracy of point location improves the network Quality of experience of user.
In a first aspect, providing a kind of start position of OFDM symbol determines method, this method includes：
Receiving terminal determines the position of the lead code starting point in received signal；The lead code includes long leading code；
The receiving terminal is mutual with presetting the K default long leading codes progress that long leading code set includes by the received signal
Related operation, obtains K operation result, and the operation result is used to characterize position of the long leading code in the lead code；
The default long leading code set is stored in the receiving terminal, K is the integer not less than 2；
The receiving terminal determines OFDM symbol according to the position and the K operation result of the lead code starting point
Start position；Wherein, the start position of the OFDM symbol is identical with the start position of the long leading code.
Optionally, the receiving terminal includes the received signal with default lead code set all default leading
Code carries out computing cross-correlation, obtains K operation result, including：
The receiving terminal utilizes formulaComputing cross-correlation is carried out, obtains the K value of m；Institute
The value of m is stated for characterizing the m sampled point that the start position of the long leading code is located at the lead code；
Wherein, zm+qFor the time-domain expression of the m+q sampled point in the received signal,For the default length
The time-domain expression of the conjugation of k-th of q-th of sampled point for presetting long leading code in leading code set, 0≤q≤Q-1, Q are described pre-
If the length of long leading code；Φ′zpk(m) it is m-th of sampled point of the received signal and k-th of preset long leading code q-th
The computing cross-correlation of the conjugation of sampled point as a result, 0≤k≤K-1,To cause Φ 'zpk(m) value of m when obtaining maximum value.
Optionally, the receiving terminal includes the received signal with default lead code set all default leading
Code carries out computing cross-correlation, obtains K operation result, including：
The receiving terminal utilizes formulaComputing cross-correlation is carried out, is obtained
The K value of m；The start position that the value of the m is used to characterizing the long leading code is located at m-th of the lead code and samples
Point；
Wherein, Zk,m+qFor the frequency-domain expression of the m+q sampled point of signal of k-th of user in the received signal,For the frequency-domain expression of the conjugation of q-th of sampled point of k-th of default lead code in the default lead code set, 0≤
Q≤Q-1, Q are the length for presetting long leading code；HkFrequency domain for the channel response of k-th of user in the received signal
Expression formula, Nk' the frequency-domain expression for the additive white Gaussian noise AWGN of k-th of user in the received signal；Φ′zpk
(m) the conjugation cross-correlation for m+q sampled point of the received signal and k-th of q-th of sampled point for presetting long leading code
Operation result, 0≤k≤K-1,To cause Φ 'zpk(m) value of m when obtaining maximum value.
Optionally, the receiving terminal is determined according to the position and the K operation result of the lead code starting point
The start position of OFDM symbol, including：
The receiving terminal determines the average value of the K value of the m；In the corresponding lead code of the average value
The position of sampled point is start position of the long leading code in lead code；
The receiving terminal determines the received signal according to the position and the average value of the lead code starting point
Described in OFDM symbol start position.
Second aspect provides a kind of start position of OFDM symbol and determines equipment, which includes：
Determination unit, for determining the position of the lead code starting point in received signal；The lead code includes length and leads
Code；
Arithmetic element, for the received signal to be carried out with presetting the K default long leading codes that long leading code set includes
Computing cross-correlation, obtains K operation result, and the operation result is used to characterize position of the long leading code in the lead code
It puts；The default long leading code set is stored in the receiving terminal, K is the integer not less than 2；
The determination unit is additionally operable to be determined according to the position and the K operation result of the lead code starting point
The start position of OFDM symbol；Wherein, the start position of the OFDM symbol is identical with the start position of the long leading code.
Optionally,
The arithmetic element, specifically for utilizing formulaComputing cross-correlation is carried out, obtains m
K value；The start position that the value of the m is used to characterizing the long leading code is located at m-th of the lead code and samples
Point；
Wherein, zm+qFor the time-domain expression of the m+q sampled point in the received signal,For the default length
The time-domain expression of the conjugation of k-th of q-th of sampled point for presetting long leading code in leading code set, 0≤q≤Q-1, Q are described pre-
If the length of long leading code；Φ′zpk(m) it is m-th of sampled point of the received signal and k-th of preset long leading code q-th
The computing cross-correlation of the conjugation of sampled point as a result, 0≤k≤K-1,To cause Φ 'zpk(m) value of m when obtaining maximum value.
Optionally,
The arithmetic element, specifically for utilizing formulaIt carries out mutual
Operation is closed, obtains the K value of m；The start position that the value of the m is used to characterize the long leading code is located at the lead code
M-th of sampled point；
Wherein, Zk,m+qFor the frequency-domain expression of the m+q sampled point of signal of k-th of user in the received signal,For the frequency-domain expression of the conjugation of q-th of sampled point of k-th of default lead code in the default lead code set, 0≤
Q≤Q-1, Q are the length for presetting long leading code；HkFrequency domain for the channel response of k-th of user in the received signal
Expression formula, Nk' the frequency-domain expression for the additive white Gaussian noise AWGN of k-th of user in the received signal；Φ′zpk
(m) the conjugation cross-correlation for m+q sampled point of the received signal and k-th of q-th of sampled point for presetting long leading code
Operation result, 0≤k≤K-1,To cause Φ 'zpk(m) value of m when obtaining maximum value.
Optionally,
The determination unit, the average value of the K value specifically for determining the m；The average value is corresponding described
The position of sampled point in lead code is start position of the long leading code in lead code；And according to the lead code starting point
Position and the average value determine the start position of OFDM symbol described in the received signal.
The third aspect provides a kind of computer installation, and described device includes at least one processor, and the processor is used
The start position side of determining of the OFDM symbol provided such as first aspect is provided when the computer program stored in memory is performed
The step of method.
Fourth aspect provides a kind of computer readable storage medium, is stored thereon with computer program, the computer
The step of start position of the OFDM symbol provided such as first aspect determines method is realized when program is executed by processor.
In embodiments of the present invention, after the start position of lead code is determined, by received signal with being deposited in receiving terminal
Multiple mutually different default long leading codes of storage carry out computing cross-correlation, and then according to K operation result and of lead code
The start position of the point long leading code of location determination.Wherein, when determining position of the long leading code in lead code, by with it is multiple pre-
If long leading code carries out cross-correlation, multiple and different operation results can be then obtained in this way, can both obtain multiple long leading codes preceding
The result of start position in leading code, then the start position of the long leading code of the weak user of signal can also be included in determining more
, finally then can be more accurate come the start position of determining long leading code according to multiple results in a start position, i.e., symbol rises
The positioning of point position is more accurate, correspondingly, signal is decoded into power higher, the network Quality of experience of user also can higher.
Description of the drawings
It in order to illustrate the technical solution of the embodiments of the present invention more clearly, below will be to required in the embodiment of the present invention
The attached drawing used is briefly described, it should be apparent that, attached drawing described below is only some embodiments of the present invention,
For those of ordinary skill in the art, without creative efforts, it can also be obtained according to these attached drawings
Other attached drawings.
Fig. 1 is the schematic diagram of the possible outcome of the start position of OFDM symbol of the prior art；
Fig. 2 is communication system sub-carriers distribution schematic diagram provided in an embodiment of the present invention；
Fig. 3 is the flow diagram that user equipment provided in an embodiment of the present invention carries out uplink communication with base station；
Fig. 4 is that the start position of OFDM symbol provided in an embodiment of the present invention determines the flow diagram of method；
Fig. 5 is the data generation of user equipment provided in an embodiment of the present invention and transmission flow schematic diagram；
Fig. 6 is process flow schematic diagram of the base station provided in an embodiment of the present invention to received signal；
Fig. 7 is a kind of structure diagram of lead code provided in an embodiment of the present invention；
Fig. 8 and Fig. 9 is the difference power of two user equipmenies provided in an embodiment of the present invention difference location algorithm when being 0
Comparative result schematic diagram；
Figure 10 and Figure 11 be two user equipmenies provided in an embodiment of the present invention difference power be -3db when difference positioning calculate
The Comparative result schematic diagram of method；
Figure 12 and Figure 13 be two user equipmenies provided in an embodiment of the present invention difference power be -6db when difference positioning calculate
The Comparative result schematic diagram of method；
Figure 14 and Figure 15 be two user equipmenies provided in an embodiment of the present invention difference power be -9db when difference positioning calculate
The Comparative result schematic diagram of method；
Figure 16 is that the start position of OFDM symbol provided in an embodiment of the present invention determines a kind of structure diagram of equipment；
Figure 17 is a kind of structure diagram of computer installation provided in an embodiment of the present invention.
Specific embodiment
Purpose, technical scheme and advantage to make the embodiment of the present invention are clearer, below in conjunction with the embodiment of the present invention
In attached drawing, the technical solution in the embodiment of the present invention is clearly and completely described.
Hereinafter, the part term in the embodiment of the present invention is explained, in order to which those skilled in the art manage
Solution.
User equipment refers to the equipment for providing a user voice and/or data connectivity, such as can include having nothing
The portable equipment of line linkage function or the processing equipment for being connected to radio modem.The user equipment can be through wireless
Access net (Radio Access Network, RAN) communicates with core net, and voice and/or data are exchanged with RAN.The use
Family equipment can include UE, wireless terminal device, mobile terminal device, subscriber unit (Subscriber Unit), subscriber station
(Subscriber Station), movement station (Mobile Station), mobile station (Mobile), distant station (Remote
Station), access point (Access Point, AP), remote terminal equipment (Remote Terminal), access terminal equipment
(Access Terminal), subscriber terminal equipment (User Terminal), user agent (User Agent) or user's dress
Standby (User Device) etc..For example, mobile phone (or being " honeycomb " phone) can be included, there is mobile terminal device
Computer, portable, pocket, hand-held, built-in computer or vehicle-mounted mobile device.For example, personal communication industry
Business (Personal Communication Service, PCS) phone, wireless phone, Session initiation Protocol (SIP) phone, nothing
Line local loop (Wireless Local Loop, WLL) is stood, personal digital assistant (Personal Digital
Assistant, PDA), the equipment such as intelligent wearable equipment.
Base station refers to the accession in net and is communicated in the air by one or more cells with wireless terminal device on interface
Equipment.Base station can be used for mutually being turned the air frame received and procotol (Internet Protocol, IP) grouping
It changes, as the router between the rest part of user equipment and access net, wherein accessing the rest part of net may include IP network
Network.Base station also tunable is to the attribute management of air interface.For example, base station can include long term evolution (Long Term
Evolution, LTE) system or evolution LTE system (LTE-Advanced, LTE-A) in evolved base station (eNB or e-
NodeB, evolutional Node B) or can also be including next-generation node B (the next generation in 5G systems
Node B, gNB), the embodiment of the present invention does not limit.
Technical solution provided in an embodiment of the present invention is introduced below in conjunction with the accompanying drawings.
Method provided in an embodiment of the present invention can be applied to the signal receiving end in communication system, the communication system example
Can be such as ofdma communication system, therefore before method provided in an embodiment of the present invention is described in detail, below
The communication system of the embodiment of the present invention will be described.
Wherein, the system channel bandwidth of the ofdma communication system of the embodiment of the present invention be C, the quantity of system sub-carriers
For N, if using M continuous subcarrier as minimum resource unit (Resource Unit, RU), then, which can prop up
The maximum number of user held is K=N/M, and K user shares the transmission that this N number of subcarrier carries out signal, if k-th of user occupancy
Subcarrier number be Nk, then haveSpecifically, referring to Fig. 2, each occupied subcarrier of user equipment is equal
It is continuous, such as it is to number the subcarrier for being 0~5, the 2nd user that the 1st user equipment, which sends the subcarrier that signal occupies,
It is the subcarrier that number is 6~15 that equipment, which sends the subcarrier that signal occupies,.
Wherein, the subcarrier that the 1st user equipment and the 2nd user equipment occupy further includes data subcarrier, pilot tone
Subcarrier and protection subcarrier, wherein, data subcarrier be used for carry data signals, pilot sub-carrier for offset estimation and/
Or channel estimation etc., subcarrier is protected for the subcarrier of different user devices to be protected not overlap.As it can be seen that each user
It communicates on the subcarrier oneself occupied, therefore the data between different user are separated from each other on frequency domain, but
In the time domain, each user occupies the entire OFDM symbol time, i.e., the data that receiving terminal receives are the number of all users
According to by the summation after wireless channel.
Fig. 3 is referred to, is the process that multiple user equipmenies carry out uplink communication with base station, wherein, base station is receiving terminal,
1~user equipment of user equipment K is transmitting terminal.Base station need by trigger frame realize it is synchronous between user, i.e., in user
Before equipment sends signal, start to send letter after the time that base station is indicated by trigger frame notifying user equipment in frame period
Number.User equipment can also first send one section of lead code and determine in order to which base station carries out frame starting point before the transmission for carrying out signal
Position, offset estimation, channel estimation etc..It can be seen that, 1~user equipment of user equipment K is sent out in the trigger frame of base station in Fig. 3
Proceed-to-send signal at the time of frame period after sending indicates, i.e., 1~user equipment of user equipment K first sends lead code, then sends out
Actual needs is sent to be sent to the data of base station, data can include multiple OFDM symbols.Wherein, due to different user devices phase
It is different for the position of base station, and the channel fading that the signal of each user equipment transmission is undergone also differs, therefore real
The signal of different user devices reaches time of base station still difference on border, and which results in each user equipmenies
The intensity of the signal of user equipment that the lead code of transmission has occurred aliasing and base station receives has differences.
Fig. 4 is referred to, the embodiment of the present invention provides a kind of start position of OFDM symbol and determines method, and this method includes：
Step 401：Receiving terminal determines the position of the lead code starting point in received signal；Lead code include short-range missile code and
Long leading code；
Step 402：Receiving terminal is mutual with presetting the K default long leading codes progress that long leading code set includes by received signal
Related operation, obtains K operation result, and operation result is used to characterize position of the long leading code in lead code；It is stored in receiving terminal
Long leading code set is preset, and presets the K items that long leading code set includes and presets that long leading code is different, K is whole not less than 2
Number；
Step 403：Receiving terminal determines long in received signal according to the position and K operation result of lead code starting point
The start position of leading code；Wherein, the start position of long leading code is identical with the start position of OFDM symbol.
In the embodiment of the present invention, receiving terminal can be realized by base station or user equipment, wherein, when receiving terminal is
During base station, receiving terminal can receive the signal of user equipment transmission；Alternatively, receiving terminal may be user equipment, then receiving terminal
The signal of base station transmission can be received.It below will be by receiving terminal to be described for base station.Where it is assumed that user equipment is sent out
The signal sent can use x (t) to represent, then the signal that k-th of user equipment is sent can then use xk(t) it represents, then base station
Received signal can be as follows：
Wherein, hk(t) channel response of k-th of user equipment is represented, z (t) represents additive white Gaussian noise (Additive
White Gaussian Noise, AWGN).
In the embodiment of the present invention, in order to which more directly method is described, two will be included with communication system below
It is described for the simple scenario of user equipment.Wherein, when only there are two during user equipment, each user equipment respectively occupies
The communication bandwidth of entire communication system half, such as when communication system sub-carriers quantity is N, user equipment 1 occupies number and is
The subcarrier of 0~(N/2-1), user equipment 2 occupy the subcarrier that number is N/2~N.In an OFDM symbol, two use
The data generation of family equipment and transmission flow are as shown in Figure 5.
Wherein, X1,0~X1,N/2-1For the frequency domain data that user equipment 1 is sent by a subcarriers of the 0th~(N/2-1), i.e.,
1 occupied subcarrier of user equipment is the 0th~(N/2-1) a subcarrier, and on its remaining sub-carriers, it is that there is no users
The data of the transmission of equipment 1；X2,N/2+1~X2,N-1It is sent for user equipment 2 by a subcarriers of (N/2+1)~(N-1)
Frequency domain data, i.e., 2 occupied subcarrier of user equipment be a subcarriers of (N/2+1)~(N-1), and its minor carry
It is the data of the transmission there is no user equipment 2 on wave；Wherein, the N/2 subcarrier is used for as protection subcarrier, and
Any data are not carried.
After user equipment generates frequency domain data, need frequency domain data passing through inverse fast Fourier transform
(Inverse Fast Fourier Transform, IFFT) is converted into time domain data, and transformed time domain data is in the time domain
It is continuous, such as the signal of user equipment 1 by the data in time domain after IFFT can be l1,0~l1,n-1, user equipment
2 frequency domain data can be l by the data in time domain after IFFT2,0~l2,n-1, wherein, n is the quantity of sampled point.
Further, after adding CP before time domain data after conversion, each time domain data is gone here and there and is changed, i.e.,
The transmission sequence of each time domain data is ranked up, then can sequentially be sent according to this when being sent.User sets
It is standby gone here and there and changed after, then the data that can will send modulate data on frequency band by frequency modulation operation, i.e. in Fig. 5
The data of shown user equipment 1 withBe multiplied and, the data of user equipment 2 withIt is multiplied, wherein, fcFor
The centre frequency of frequency band.Each data can be carried by corresponding subcarrier by frequency modulation operation, so as to be sent to
Base station.Due to being overlapped in the data of time domain, two different user devices, so represented in Figure 5 with phase Calais,
The signal y (t) eventually received is the summation of the signal of two user equipmenies.
Fig. 6 is referred to, the process chart after signal y (t) is received for base station.Wherein, base station receives signal y
(t) it after, is sampled first by analog-digital converter (Analog-to-digital converter, ADC) by mould
Intend signal y (t) and be converted into digital signal zm, then to the digital signal z after being gone here and there and being changedmSynchronize, i.e., frame starting point with
Symbol plays point location, in order to subsequently carry out the operations such as channel estimation and offset estimation.Wherein, frame starting point and OFDM symbol
The positioning of start position is the follow-up basis for carrying out the operations such as channel estimation and offset estimation, if frame starting point and OFDM symbol
Start position position inaccurate, then subsequent channel estimation also can not be carried out accurately with offset estimation, thus frame starting point
Positioning with the start position of OFDM symbols is particularly critical step for signal decoding.Below then will with regard to frame starting point with
The positioning of the start position of OFDM symbol is specifically described.
Continuing with referring to Fig. 4, in the embodiment of the present invention, base station obtains received signal z in samplingmLater, then it can determine whether
The position of lead code starting point in received signal carries out frame starting point positioning.
Specifically, frame starting point is positioned for searching wireless frame head, i.e., the starting point position of radio frames is found from received signal
It puts.Wherein, since user equipment is when sending signal, lead code all can first be sent, that is to say, that the start position of radio frames
The namely start position of lead code.Fig. 7 is referred to, is a kind of structure diagram of lead code, wherein, lead code includes short
Leading code (Short Training Field, STF) and long leading code (Long Training Field, LTF).Short-range missile code is by 2
OFDM symbol forms, when a length of 4 microsecond (us) of each OFDM symbol, the waveform of 5 repetitions that each OFDM symbol includes,
Repetition period is 0.8us, and the training sequence that each repetition period carries is identical.Long leading code is accorded with by 1 CP and 2 OFDM
Number form, total duration 8us, wherein, the waveform of 2 OFDM symbols is identical.It can from the structure chart of lead code
It arrives, the start position of lead code i.e. the start position of short-range missile code.Since short-range missile code includes the waveform of multiple repetition periods,
So then it can obtain the start position of short-range missile code by postponing auto-correlation computation.Specifically, the public affairs of delay auto-correlation computation
Formula is as follows：
Wherein, ΦDC(m) the received signal z obtained to sampling is representedmIn m-r sampled point and the m-r sampling
The conjugation of l-th sampled point before point carries out auto-correlation computation, and m >=L+1, R are the recurrence interval length of signal, and L is two
The spacing distance of auto-correlation computation window, L are the integral multiple of R, wherein, the repetition period of short-range missile code is 0.8us, then channel
Recurrence interval length R is the product of repetition period and system bandwidth.zm-rRepresent the m-r sampled point, 0≤r≤R,
Represent the conjugation of the l-th sampled point after the m-r sampled point.Result to cause above-mentioned auto-correlation computation obtains most
The value for the m being worth greatly, i.e.,To cause ΦDC(m) value of m during acquirement maximum value.Wherein, the value of m is corresponding adopts
Sampling point is the start position of lead code, that is, frame starting point position.
For example, it is by by received signal z when delay autocorrelation calculation is carried out as L=RmIn preceding L
A sampled point is as first auto-correlation computation window, and first auto-correlation computation window includes sampled point 0~L-1, second
Auto-correlation computation window includes sampled point L~(2L-1), and so on, by two auto-correlation computations since sampled point 2L-1
The sampled point in same position that window includes is added again after being multiplied, i.e., sampled point 2L-1 is multiplied with sampled point L-1,
Sampled point 2L-2 is multiplied with sampled point L-2, and so on, finally the result of multiplication is added again.
After getting frame start position, then need to carry out the positioning of the start position of OFDM symbol.If according to existing
Technology carries out the positioning of the start position of OFDM symbol, and the example for equally continuing to use above-mentioned two user equipment illustrates, base station
The signal of sampling acquisition is carried out to received signal can represent as follows：
Wherein, x1,m、x2,mThe signal of user equipment 1, user equipment 2, h in respectively m-th of sampled point1、h2Respectively
The channel response of user equipment 1, user equipment 2.
For the long leading code p being pre-stored in base stationq, there are equation below：
pq=IFFT (Xq)=IFFT (X1,q+X2,q)=IFFT (X1,q)+IFFT(X2,q)
Wherein, XqFor to pqCarry out the expression formula after FFT transform, X1,qAnd X2,qRespectively XqMiddle relative user equipment 1
The corresponding long code-guiding sequence with user equipment 2, for example, X1,qOnly there are long leading code sequences on 1 corresponding subcarrier of user equipment
Row, and there is no data, X for the part of 2 corresponding subcarrier of relative user equipment2,qIt is similar, then then to have X1,q·X2,q=
0.Wherein, zm+qIt can then be expressed as：
Then
Wherein, H1And H2The respectively frequency-domain expression of the channel response of user equipment 1 and user equipment 2, i.e., to user
The channel response of equipment 1 and user equipment 2 carries out the expression formula after FFT transform；The frequency domain table of conjugation for long leading code
Up to formula；N1,oAnd N2,oThe respectively frequency-domain expression of 2 corresponding AWGN of user equipment 1 and user equipment.
Due to X1,mAnd X2,mDifferent subcarriers is occupied respectively, therefore in the corresponding X of same sub-carrier positions1,mWith
X2,mThere can not possibly be value simultaneously, then existSo above-mentioned formula can further indicate that
For：
Since the position where different user devices may be different, and different user devices are relative to the distance of base station
The signal attenuation that possible different and distinct device signals are undergone in transmission process is also different, therefore is easy to
The signal for different user devices occur reaches the time of base station and signal strength has differences.For example, if | H1| ＜ | H2
|, i.e., the signal strength of user equipment 1 is less than the signal strength of user equipment 2, then to Φzp(m) result user equipment 2
Numerical value bigger occupied by data, i.e., user equipment 2 is to Φzp(m) the disturbance degree bigger that result is played, i.e., it is final to obtain
M value be more partial to user equipment 2 OFDM symbol start position, then in user equipment 1 and user equipment 2
OFDM symbols start position difference it is bigger when, the start position positioning of the OFDM symbol of user equipment 1 is then inaccurate,
It is likely to cause ICI and ISI so as to the signal of user equipment 1.
It has been pre-stored in the embodiment of the present invention, in base station and has preset long leading code set, this is preset long leading code set and includes K items
Long leading code is preset, wherein, K is the integer not less than 2, and the quantity of user equipment that the quantity of K can be accommodated with communication system has
It closes.
In the embodiment of the present invention, after the position that lead code starting point in received signal is determined in base station, then it can carry out
The start position of OFDM symbol determines.Wherein, by the way that received signal is default with presetting K that long leading code set includes
Long leading code carries out computing cross-correlation, obtains K operation result, and obtained operation result is i.e. for characterizing long leading code in lead code
In position.
Specifically, the first calculation is, base station can carry out auto-correlation computation by the following formula：
Wherein, zm+qFor the time-domain expression of the m+q sampled point in received signal, m=0,1,2 ..., 0≤q≤
Q-1, Q are the length for presetting long leading code,To preset q-th of sampled point of k-th of default long leading code in long leading code set
The time-domain expression of conjugation；Φ′zpk(m) it is m-th of sampled point of received signal and k-th of cross-correlation for presetting long leading code
Operation result, 0≤k≤K-1,The value of m during so that computing cross-correlation result obtains maximum value, i.e.,To cause Φ 'zpk
(m) value of m when obtaining maximum value.Wherein, Φ 'zpk(m) represent that the slip of received signal and each default long leading code is mutual
Correlation, for example, m be 0 when, q be 0 when, then since the 0th sampled point in received signal with k-th preset long leading code in
0th sampled point is multiplied, and next multiplication then starts to preset the 1st sampled point in long leading code with k-th with the 1st sampled point
It is multiplied, until during q=Q-1, as the q-1 sampled point starts to be multiplied with the Q-1 sampled point in k-th of default long leading code,
Then multiplication duration leading code is returned to the 0th sampled point next time, i.e., by the Q sampled point in received signal start with
The 0th sampled point is multiplied in k-th of default long leading code, and m at this time is equal to Q, so cycle.
Herein it is to be understood that, Φ 'zpk(m) and ΦDC(m) subscript zp and DC in are respectively used to indicate different
Operation, for example, ΦDC(m) DC in is shown to be auto-correlation computation, Φ 'zpk(m) zp in is shown to be computing cross-correlation.
Secondary cross-correlation fortune can be obtained by the way that received signal is carried out computing cross-correlation with k-th of default long leading code
The value of the m of calculation, the value of the m of the secondary computing cross-correlation represent that the start position of the OFDM symbols of k-th of user equipment is located at
M-th of sampled point of lead code.So by K computing cross-correlation, then the K value of m can be obtained to get reception is arrived
The start position of the corresponding OFDM symbols of K user equipment in signal.
Wherein, it can see by the first calculation, when the length of long leading code is Q, then above-mentioned cross-correlation fortune
Complex multiplication number needed for calculating is Q2, it can be seen that when the value of Q is larger, the calculating of computing cross-correlation is excessively complicated.
Such as in practical communication system, Q is usually 128, then the required complex multiplication number of computing cross-correlation is 1282,
Calculation amount is excessive.Therefore, in the start position for carrying out OFDM symbol timing really, second of calculation can also be used, i.e.,
To received signal zm+qQ point FFT transform is carried out, obtains Zm+q；And the K to being pre-stored in base station default long leading codes carry out FFT
Conjugation is sought after transformation, is obtainedCertainly, in order to reduce the calculating in the start position timing really of OFDM symbol
It measures, can have been completed that K default long leading codes carry out the step of FFT transform seek conjugation later with regard to storage in a base station in advance
Default long leading code afterwards, that is, directly willStorage is in a base station.Obtaining Zm+qWithIt later, then can be straight
It connects Zm+qWithIt is multiplied respectively, and Q/K points IFFT transformation is carried out to the result of multiplication, will be multiplied in frequency domain
Result be transformed into time domain, i.e. equation below：
Wherein, Zk,m+qFor the frequency-domain expression of the signal of k-th of user equipment in the received signal,It is described
The frequency-domain expression of the conjugation of q-th of sampled point of k-th of default lead code in default lead code set；HkFor the reception
Signal in k-th of user equipment channel response frequency-domain expression, Nk' set for k-th of user in the received signal
The frequency-domain expression of standby additive white Gaussian noise AWGN； Φ′zpk(m) it is m-th of sampled point of the received signal and the
K preset the computing cross-correlations of long leading code as a result,The value of m during so that computing cross-correlation result obtains maximum value, i.e.,
To cause Φ 'zpk(m) value of m when obtaining maximum value；
Wherein, it in second of calculation, is converted by IFFT instead of computing cross-correlation, so as to reduce calculation amount.
Specifically, the complexity of Q point FFT transform isQ/K points IFFT transformation complexity beI.e. second
Total complexity of calculation isAs it can be seen that when the value of Q is bigger, second calculation is answered
Miscellaneous degree is lower relative to the calculation amount of the first calculation.
In the embodiment of the present invention, K of m can be obtained by the first calculation or second of calculation
Value, the i.e. start position corresponding to the OFDM symbol of K user equipment.
In the embodiment of the present invention, after K value for obtaining m, then the average value of the K value of m can determine whether；This is flat
The position of sampled point in the corresponding lead code of mean value is start position of the long leading code in lead code；It is risen according to lead code
The position and average value of point determine the start position of OFDM symbol in received signal, i.e., according to determining frame starting point and
The position of the sampled point of average value instruction can then determine the start position of OFDM symbol in received signal.In this way, final
To the start position of OFDM symbol can't be partial to some user equipment, so as to avoid certain customers' equipment
The technical issues of start position position inaccurate of OFDM symbol.
Equally it is described so that the communication system of two user equipmenies is to the start position of above-mentioned OFDM symbol as an example.When
When communication system only includes two user equipmenies, then it can be pre-stored two conjugation for presetting long leading code in a base station, i.e.,
WithIf the signal received is zm+q, to zm+qAfter carrying out Q point FFT transform, then Z can be obtainedm+q, then by Zm+qRespectively
According to user equipment bandwidth location withIt is multiplied, and then obtains the corresponding OFDM symbol of the two user equipmenies respectively
Start position, then the start position of the corresponding OFDM symbol of the two user equipmenies is carried out taking average operation, so as to obtain
The average value of the start position of OFDM symbol, and accorded with the average value as the OFDM of the two finally determining user equipmenies
Number start position.The formula of the algorithm of the start position of the OFDM symbol of the above-mentioned process for being directed to two user equipmenies is as follows：
Wherein, wherein, Z1,m+qAnd Z2,m+qThe signal of user equipment 1 and user equipment 2 respectively in received signal
Frequency-domain expression,WithQ-th of sampling of the 1st and the 2nd default lead code in respectively default lead code set
The frequency-domain expression of the conjugation of point；H1And H2The channel response of user equipment 1 and user equipment 2 respectively in received signal
Frequency-domain expression, N1′,OAnd N2′,OThe frequency domain presentation of the AWGN of user equipment 1 and user equipment 2 respectively in received signal
Formula；WithRespectively so that Φ 'zp1(m) and Φ 'zp2(m) value of m when obtaining maximum value,ForWithAverage value.
If if channel and channel response are identical used by the two user equipmenies, it can be seen that above-mentioned
Formula is substantially equal to the start position ranging formula of the OFDM symbol of the prior art, thus of above-mentioned OFDM symbol
Point position location algorithms are also that can be compatible with for the start position location algorithm of the OFDM symbol of the prior art.It is in addition, right
In only there are one during user, location algorithm of the invention is equally applicable, i.e. K is 1 situation, then need to only be prestored in a base station
Long leading code is preset in storage one, i.e., similar with the algorithm of the prior art, but second of calculation through the embodiment of the present invention
Calculation amount can also be reduced, thus the embodiment of the present invention is also more excellent than prior art performance when K is 1.
In the embodiment of the present invention, also by comparing symbol location algorithm of the prior art and the embodiment of the present invention
For the location algorithm of OFDM symbol in the case of different signal-to-noise ratio (Signal to Noise SNR), two users' different capacity is poor
The influence of Packet Error Ratio (Packet Error Rate, PER) during to receiving terminal demodulated signal, and then to the embodiment of the present invention
The location algorithm of OFDM symbol is verified.Wherein, symbol of the prior art calculates position method and is hereinafter referred to as traditional algorithm, this
The location algorithm of the OFDM symbol of inventive embodiments is hereinafter referred to as new algorithm.Used by verification communication system for only there are two
The ofdma communication system of user equipment, wherein, system bandwidth is set as 40MHz, and number of subcarriers is 128, each user
Respectively 64 subcarriers of distribution, CP length are 0.8us, two users when it is bigger than normal small for 0.4us, it is leading to use binary phase-shift
Keying (Binary Phase Shift Keying, BPSK) is modulated, and data field uses 64 phase quadrature amplitude modulations
(Quadrature Amplitude Modulation, QAM) is modulated, and the length for the data segment that each user sends is 49216
Byte, channel are awgn channel.
Fig. 8 and Fig. 9 are referred to, the Comparative result of difference location algorithm when the difference power of respectively two user equipmenies is 0
Figure.Wherein, when the difference power of signal that user 1 and 2 corresponding user equipment 1 of user and user equipment 2 are sent is 0, i.e., two
When the signal strength that a user equipment is sent is identical, the PER of traditional algorithm and new algorithm is basic one with the SNR trend changed
It causes, and the PER difference of signal that two user equipmenies are sent is little.In addition, in identical SNR, the performance of new algorithm
Slightly it is better than traditional algorithm.
Figure 10 and Figure 11 are referred to, the knot of difference location algorithm when the difference power of respectively two user equipmenies is -3db
Fruit comparison diagram.Wherein, the difference power of the signal sent when user 1 and 2 corresponding user equipment 1 of user and user equipment 2 for-
During 3db, i.e., the signal strength that user equipment 1 is sent is slightly smaller than the signal strength of the transmission of user equipment 2, and traditional algorithm significantly goes out
The problem of having showed position inaccurate, and the PER of the signal of two user equipmenies is caused to be always 100%, but new algorithm exists
When SNR is more than 28db, the PER of the signal of two user equipmenies is far below traditional algorithm.
Figure 12 and Figure 13 are referred to, the knot of difference location algorithm when the difference power of respectively two user equipmenies is -6db
Fruit comparison diagram.Wherein, the difference power of the signal sent when user 1 and 2 corresponding user equipment 1 of user and user equipment 2 for-
During 6db, i.e., the signal strength that user equipment 1 is sent is much less than the signal strength of the transmission of user equipment 2, it can be seen that signal
The signal of the weaker user equipment of intensity can not be correctly decoded data completely, and the user equipment that signal strength is weaker
Signal can also be correctly decoded data at this time, and can significantly see, the PER of new algorithm is significantly lower than traditional algorithm.
Figure 14 and Figure 15 are referred to, the knot of difference location algorithm when the difference power of respectively two user equipmenies is -9db
Fruit comparison diagram.Wherein, the difference power of the signal sent when user 1 and 2 corresponding user equipment 1 of user and user equipment 2 for-
During 9db, i.e., when the signal strength that user equipment 1 is sent differs bigger with the signal strength that user equipment 2 is sent, it can be seen that
The signal of the weaker user equipment of signal strength can not be correctly decoded data completely, and the user that signal strength is weaker
The signal of equipment can also be correctly decoded data at this time, and can significantly see, the PER of new algorithm is calculated significantly lower than tradition
Method.
Thus, it will be seen that the location algorithm of the OFDM symbol of the embodiment of the present invention is substantially better than the calculation of the prior art
Method, and advantage is particularly evident when the signal strength difference of user equipment is larger.
In conclusion in the embodiment of the present invention, after the start position of lead code is determined, by received signal with connecing
The multiple mutually different default long leading codes stored in receiving end carry out computing cross-correlations, and then according to K operation result and preceding
The start position of leading code determines the start position of long leading code.Wherein, when determining position of the long leading code in lead code, pass through
Cross-correlation is carried out with multiple default long leading codes, multiple and different operation results can be then obtained in this way, can both obtain multiple length
The result of start position of the leading code in lead code, then the start position of the long leading code of the weak user of signal can also be included in
, finally then can be more accurate come the start position of determining long leading code according to multiple results in determining multiple start positions,
That is symbol start position positioning is more accurate, correspondingly, signal is decoded into power higher, the network Quality of experience of user
It can higher.
Figure 16 is referred to, based on same inventive concept, one embodiment of the invention provides a kind of start position of OFDM symbol
Determine equipment 160, which includes：
Determination unit 1601, for determining the position of the lead code starting point in received signal；Lead code includes length and leads
Code；
Arithmetic element 1602, for received signal to be carried out with presetting the K default long leading codes that long leading code set includes
Computing cross-correlation, obtains K operation result, and operation result is used to characterize position of the long leading code in lead code；It is deposited in receiving terminal
It has stored up and has preset long leading code set, K is the integer not less than 2；
Determination unit 1601 is additionally operable to determine OFDM symbol according to the position and K operation result of lead code starting point
Start position；Wherein, the start position of OFDM symbol is identical with the start position of long leading code.
Optionally,
Arithmetic element 1602, specifically for utilizing formulaComputing cross-correlation is carried out, obtains m
K value；The start position that the value of m is used to characterize long leading code is located at m-th of sampled point of lead code；
Wherein, zm+qFor the time-domain expression of the m+q sampled point in received signal,To preset long leading code set
In k-th preset long leading code q-th of sampled point conjugation time-domain expression, 0≤q≤Q-1, Q for it is described preset long leading code
Length；Φ′zpk(m) conjugation for m-th of sampled point of received signal and k-th of q-th of sampled point for presetting long leading code
Computing cross-correlation as a result, 0≤k≤K-1,To cause Φ 'zpk(m) value of m when obtaining maximum value.
Optionally,
Arithmetic element 1602, specifically for utilizing formulaIt carries out mutual
Operation is closed, obtains the K value of m；The start position that the value of m is used to characterizing long leading code is located at m-th of lead code and samples
Point；
Wherein, Zk,m+qFor the frequency-domain expression of the m+q sampled point of signal of k-th of user in received signal,
To preset the frequency-domain expression of the conjugation of q-th of sampled point of k-th of default lead code in lead code set, 0≤q≤Q-1, Q
For the length for presetting long leading code；HkFor the frequency-domain expression of the channel response of kth user in received signal, Nk' be
The frequency-domain expression of the additive white Gaussian noise AWGN of k-th of user in received signal；Φ′zpk(m) it is received signal
The conjugation computing cross-correlation of q-th of sampled point of long leading code is preset in m+q sampled point and k-th as a result, 0≤k≤K-1,
To cause Φ 'zpk(m) value of m when obtaining maximum value.
Optionally,
Determination unit 1601, the average value of the K value specifically for determining m；Adopting in the corresponding lead code of average value
The position of sampling point is start position of the long leading code in lead code；And it is determined according to the position and average value of lead code starting point
The start position of OFDM symbol in received signal.
The equipment can be used for performing the method that embodiment shown in Fig. 4 is provided, therefore, for each work(of the equipment
Function that energy module can be realized etc. can refer to the description of embodiment shown in Fig. 4, seldom repeat.
Figure 17 is referred to, one embodiment of the invention also provides a kind of computer installation, which includes at least one
A processor 1701, at least one processor 1701 are used to realize shown in Fig. 4 when performing the computer program stored in memory
The start position of OFDM symbol that provides of embodiment the step of determining method.
Optionally, at least one processor 1701 can specifically include central processing unit (CPU), specific application integrates electricity
Road (application specific integrated circuit, ASIC) can be that one or more is used to control journey
Sequence perform integrated circuit, can be use site programmable gate array (field programmable gate array,
FPGA) the hardware circuit of exploitation, can be baseband processor.
Optionally, at least one processor 1701 can include at least one processing core.
Optionally, which further includes memory 1702, and memory 1702 can include read-only memory
(read only memory, ROM), random access memory (random access memory, RAM) and magnetic disk storage.
Memory 1702 is used to store data required when at least one processor 1701 is run.The quantity of memory 1702 is one
It is or multiple.Wherein, memory 1702 is shown together in fig. 17, but it is understood that memory 1702 is not essential work(
Energy module, thus it is shown in dotted line in fig. 17.
One embodiment of the invention also provides a kind of computer readable storage medium, is stored thereon with computer program, described
Realize that the start position for the OFDM symbol that embodiment shown in Fig. 4 provides determines method when computer program is executed by processor
The step of.
In embodiments of the present invention, it should be understood that disclosed device and method, it can be real by another way
It is existing.For example, apparatus embodiments described above are only schematical, for example, the division of the unit or unit, only
For a kind of division of logic function, there can be other dividing mode in actual implementation, such as multiple units or component can combine
Or it is desirably integrated into another system or some features can be ignored or does not perform.Another point, shown or discussed phase
Coupling, direct-coupling or communication connection between mutually can be the INDIRECT COUPLING or logical by some interfaces, equipment or unit
Letter connection, can be electrical or other forms.
Each functional unit in embodiments of the present invention can be integrated in a processing unit or each unit
It can be independent physical module.
If the integrated unit is realized in the form of SFU software functional unit and is independent product sale or uses
When, it can be stored in a computer read/write memory medium.Based on such understanding, the technical side of the embodiment of the present invention
The all or part of case can be embodied in the form of software product, which is stored in a storage and is situated between
In matter, used including some instructions so that a computer equipment, such as can be personal computer, server or network
Equipment etc. or processor (processor) perform all or part of the steps of the method according to each embodiment of the present invention.It is and preceding
The storage medium stated includes：General serial bus USB (universal serial bus flash drive), movement are hard
The various media that can store program code such as disk, ROM, RAM, magnetic disc or CD.
The above, above example are only described in detail to the technical solution to the application, but above implementation
The method that the explanation of example is merely used to help understand the embodiment of the present invention, should not be construed as the limitation to the embodiment of the present invention.This
The change or replacement that those skilled in the art can readily occur in, should all cover the embodiment of the present invention protection domain it
It is interior.
Claims (10)
1. a kind of start position of orthogonal frequency division multiplex OFDM symbol determines method, which is characterized in that including：
Receiving terminal determines the position of the lead code starting point in received signal；The lead code includes long leading code；
The received signal is carried out cross-correlation fortune by the receiving terminal with presetting the K default long leading codes that long leading code set includes
It calculates, obtains K operation result, the operation result is used to characterize position of the long leading code in the lead code；It is described to connect
The default long leading code set is stored in receiving end, K is the integer not less than 2；
The receiving terminal determines the starting point of OFDM symbol according to the position and the K operation result of the lead code starting point
Position；Wherein, the start position of the OFDM symbol is identical with the start position of the long leading code.
2. the method as described in claim 1, which is characterized in that the receiving terminal is by the received signal and default lead code
Gather all default lead codes included and carry out computing cross-correlation, obtain K operation result, including：
The receiving terminal utilizes formulaComputing cross-correlation is carried out, obtains the K value of m；The m's
The start position that value is used to characterize the long leading code is located at m-th of sampled point of the lead code；
Wherein, zm+qFor the time-domain expression of the m+q sampled point in the received signal,Long leading code collection is preset to be described
The time-domain expression of the conjugation of k-th of q-th of sampled point for presetting long leading code in conjunction, 0≤q≤Q-1, Q are led for the default length
The length of code；Φ′zpk(m) it is m-th of sampled point of the received signal and k-th of q-th of sampled point for presetting long leading code
Conjugation computing cross-correlation as a result, 0≤k≤K-1,To cause Φ 'zpk(m) value of m when obtaining maximum value.
3. the method as described in claim 1, which is characterized in that the receiving terminal is by the received signal and default lead code
Gather all default lead codes included and carry out computing cross-correlation, obtain K operation result, including：
The receiving terminal utilizes formulaComputing cross-correlation is carried out, obtains the K of m
A value；The start position that the value of the m is used to characterize the long leading code is located at m-th of sampled point of the lead code；
Wherein, Zk,m+qFor the frequency-domain expression of the m+q sampled point of signal of k-th of user in the received signal,For
The frequency-domain expression of the conjugation of q-th of sampled point of k-th of default lead code in the default lead code set, 0≤q≤Q-1,
Q is the length for presetting long leading code；HkFor the frequency-domain expression of the channel response of k-th of user in the received signal,
Nk' the frequency-domain expression for the additive white Gaussian noise AWGN of k-th of user in the received signal；Φ′zpk(m) it is described
The conjugation computing cross-correlation of m+q sampled point of received signal and k-th of q-th of sampled point for presetting long leading code is as a result, 0
≤ k≤K-1,To cause Φ 'zpk(m) value of m when obtaining maximum value.
4. method as claimed in claim 2 or claim 3, which is characterized in that the receiving terminal according to the position of the lead code starting point,
And the K operation result determines the start position of OFDM symbol, including：
The receiving terminal determines the average value of the K value of the m；Sampled point in the corresponding lead code of the average value
Position be start position of the long leading code in lead code；
The receiving terminal is determined according to the position and the average value of the lead code starting point described in the received signal
The start position of OFDM symbol.
5. a kind of start position of orthogonal frequency division multiplex OFDM symbol determines equipment, which is characterized in that including：
Determination unit, for determining the position of the lead code starting point in received signal；The lead code includes long leading code；
Arithmetic element, for the received signal is mutual with presetting the K default long leading codes progress that long leading code set includes
Operation is closed, obtains K operation result, the operation result is used to characterize position of the long leading code in the lead code；Institute
It states and the default long leading code set is stored in receiving terminal, K is the integer not less than 2；
The determination unit is additionally operable to determine that OFDM is accorded with according to the position and the K operation result of the lead code starting point
Number start position；Wherein, the start position of the OFDM symbol is identical with the start position of the long leading code.
6. equipment as claimed in claim 5, which is characterized in that
The arithmetic element, specifically for utilizing formulaCarry out computing cross-correlation acquisition m K take
Value；The start position that the value of the m is used to characterize the long leading code is located at m-th of sampled point of the lead code；
Wherein, zm+qFor the time-domain expression of the m+q sampled point in the received signal,Long leading code collection is preset to be described
The time-domain expression of the conjugation of k-th of q-th of sampled point for presetting long leading code in conjunction, 0≤q≤Q-1, Q are led for the default length
The length of code；Φ′zpk(m) it is m-th of sampled point of the received signal and k-th of q-th of sampled point for presetting long leading code
Conjugation computing cross-correlation as a result, 0≤k≤K-1,To cause Φ 'zpk(m) value of m when obtaining maximum value.
7. equipment as claimed in claim 5, which is characterized in that
The arithmetic element, specifically for utilizing formulaCarry out cross-correlation fortune
It calculates, obtains the K value of m；The start position that the value of the m is used to characterize the long leading code is located at the m of the lead code
A sampled point；
Wherein, Zk,m+qFor the frequency-domain expression of the m+q sampled point of signal of k-th of user in the received signal,For
The frequency-domain expression of the conjugation of q-th of sampled point of k-th of default lead code in the default lead code set, 0≤q≤Q-1,
Q is the length for presetting long leading code；HkFor the frequency-domain expression of the channel response of k-th of user in the received signal,
Nk' the frequency-domain expression for the additive white Gaussian noise AWGN of k-th of user in the received signal；Φ′zpk(m) it is described
The conjugation computing cross-correlation of m+q sampled point of received signal and k-th of q-th of sampled point for presetting long leading code is as a result, 0
≤ k≤K-1,To cause Φ 'zpk(m) value of m when obtaining maximum value.
8. method as claimed in claims 6 or 7, which is characterized in that
The determination unit, the average value of the K value specifically for determining the m；The average value is corresponding described leading
The position of sampled point in code is start position of the long leading code in lead code；And according to the position of the lead code starting point
It puts and the average value determines the start position of OFDM symbol described in the received signal.
9. a kind of computer installation, which is characterized in that described device includes processor, and the processor is used to perform in memory
It is realized during the computer program of storage such as the step of any one of claim 1-4 the methods.
10. a kind of computer readable storage medium, is stored thereon with computer program, it is characterised in that：The computer program
It is realized when being executed by processor such as the step of any one of claim 1-4 the methods.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711463206.8A CN108156108B (en) | 2017-12-28 | 2017-12-28 | Method and device for determining starting point position of OFDM symbol |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711463206.8A CN108156108B (en) | 2017-12-28 | 2017-12-28 | Method and device for determining starting point position of OFDM symbol |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN108156108A true CN108156108A (en) | 2018-06-12 |
| CN108156108B CN108156108B (en) | 2020-12-18 |
Family
ID=62462464
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201711463206.8A Active CN108156108B (en) | 2017-12-28 | 2017-12-28 | Method and device for determining starting point position of OFDM symbol |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN108156108B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109005137A (en) * | 2018-08-17 | 2018-12-14 | 北京智芯微电子科技有限公司 | The frame synchornization method and system of ofdm system receiver |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20060140293A1 (en) * | 2004-12-27 | 2006-06-29 | Ko-Yin Lai | Method for detecting signal and estimating symbol timing |
| EP1821477A2 (en) * | 2006-02-14 | 2007-08-22 | Sony Corporation | Wireless communication apparatus and wireless communication method |
| CN101714965A (en) * | 2009-07-10 | 2010-05-26 | 北京新岸线无线技术有限公司 | Signal-timing method/device and fine frequency offset estimation method/device |
| CN102984112A (en) * | 2012-11-30 | 2013-03-20 | 南通大学 | Synchronizing method of high-speed mobile OFDM (orthogonal frequency division multiplexing) system |
| CN103297376A (en) * | 2013-06-05 | 2013-09-11 | 北京邮电大学 | Symbol synchronization method of OFDM (orthogonal frequency division multiplexing) system |
| CN104767706A (en) * | 2015-04-14 | 2015-07-08 | 东莞中山大学研究院 | MIMO OFDM timing synchronization device |
| CN105847211A (en) * | 2016-03-15 | 2016-08-10 | 东南大学 | Carrier frequency offset estimation method suitable for MIMO-OFDM (Multiple Input Multiple Output-Orthogonal Frequency Division Multiplexing) system |
| CN106453192A (en) * | 2016-11-14 | 2017-02-22 | 浙江万里学院 | Symbol synchronization method and system based on shielding complementary binary sequence pair |
| CN107360113A (en) * | 2017-07-25 | 2017-11-17 | 深圳芯之联科技有限公司 | A kind of bandwidth judges and symbol timing synchronization method and device |
-
2017
- 2017-12-28 CN CN201711463206.8A patent/CN108156108B/en active Active
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20060140293A1 (en) * | 2004-12-27 | 2006-06-29 | Ko-Yin Lai | Method for detecting signal and estimating symbol timing |
| EP1821477A2 (en) * | 2006-02-14 | 2007-08-22 | Sony Corporation | Wireless communication apparatus and wireless communication method |
| CN101714965A (en) * | 2009-07-10 | 2010-05-26 | 北京新岸线无线技术有限公司 | Signal-timing method/device and fine frequency offset estimation method/device |
| CN102984112A (en) * | 2012-11-30 | 2013-03-20 | 南通大学 | Synchronizing method of high-speed mobile OFDM (orthogonal frequency division multiplexing) system |
| CN103297376A (en) * | 2013-06-05 | 2013-09-11 | 北京邮电大学 | Symbol synchronization method of OFDM (orthogonal frequency division multiplexing) system |
| CN104767706A (en) * | 2015-04-14 | 2015-07-08 | 东莞中山大学研究院 | MIMO OFDM timing synchronization device |
| CN105847211A (en) * | 2016-03-15 | 2016-08-10 | 东南大学 | Carrier frequency offset estimation method suitable for MIMO-OFDM (Multiple Input Multiple Output-Orthogonal Frequency Division Multiplexing) system |
| CN106453192A (en) * | 2016-11-14 | 2017-02-22 | 浙江万里学院 | Symbol synchronization method and system based on shielding complementary binary sequence pair |
| CN107360113A (en) * | 2017-07-25 | 2017-11-17 | 深圳芯之联科技有限公司 | A kind of bandwidth judges and symbol timing synchronization method and device |
Non-Patent Citations (4)
| Title |
|---|
| CATT: ""Further consideration on NR RACH preamble sequence and preamble format for capacity enhancement"", 《3GPP TSG RAN WG1 MEETING NR#3 R1-1715789》 * |
| SAMSUNG: ""Interlaced transmissions for co-existence with DSRC"", 《3GPP TSG RAN WG1 MEETING #85 R1-164792》 * |
| YI GUO等: ""A NEW TIME AND FREQUENCY SYNCHRONIZATION SCHEME FOR OFDM-BASED COOPERATIVE SYSTEMS"", 《IEEE LONG ISLAND SYSTEM,APPLICATION AND TECHOLOGY(LISAT) CONFERENCE 2014》 * |
| 郝鑫: ""基于802.11ac协议的OFDM信号同步算法的研究与实现"", 《中国硕士学位论文全文数据库 信息科技辑》 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109005137A (en) * | 2018-08-17 | 2018-12-14 | 北京智芯微电子科技有限公司 | The frame synchornization method and system of ofdm system receiver |
| CN109005137B (en) * | 2018-08-17 | 2020-12-11 | 北京智芯微电子科技有限公司 | Frame synchronization method and system for OFDM system receiver |
Also Published As
| Publication number | Publication date |
|---|---|
| CN108156108B (en) | 2020-12-18 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| RU2432699C2 (en) | Signal detection in wireless communication system | |
| US8767848B2 (en) | Channel estimation based on long training symbol with doubled cyclic prefix | |
| US7742392B2 (en) | Blind carrier frequency offset estimator based on single-OFDM-symbol PN ranging code in multi-user OFDMA uplink | |
| CN102185822B (en) | OFDM/OQAM (Orthogonal Frequency Division Multiplexing/Offset Quadrature Amplitude Modulation) system and time frequency synchronization method thereof | |
| CN108632189B (en) | Method and device for sending uplink data and user equipment | |
| JP2004153676A (en) | Communication equipment, transmitter, and receiver | |
| CN109743278A (en) | The receiving handling method of leading symbol in physical frame | |
| CN107306238A (en) | Reception, sending method and the corresponding receiver and emitter of carrier (boc) modulated signals | |
| CN1791077A (en) | Time-domain and frequency-domain combined channel estimating method | |
| CN110868369A (en) | Uplink channel estimation method and device based on 5G NR system | |
| CN107086974A (en) | A kind of OFDM synchronous method under high dynamic environment | |
| CN102215204A (en) | Feedback-iteration-based OFDM/OQAM (orthogonal frequency division multiplexing/offset quadrature amplitude modulation) system as well as time-frequency synchronization method thereof | |
| CN101119350A (en) | OFDM system, fast synchronous method and sending terminal equipment | |
| CN107508780B (en) | Timing synchronization method of OFDM system based on IEEE 802.11ac | |
| CN104333527B (en) | A kind of aircraft COFDM modulation-demo-demodulation method | |
| WO2018024127A1 (en) | Signal transmission method and network device | |
| CN101442520B (en) | Timing synchronization method for radio communication system uplink | |
| CN108156108A (en) | A kind of start position of OFDM symbol determines method and apparatus | |
| CN101820407B (en) | Serial interference cancellation based frequency domain initial ranging method and system | |
| CN100521554C (en) | Frequency domain channel estimation method based on two-value full-pass sequence protection interval filling | |
| CN105453607B (en) | The transmission method and transmission device of WLAN | |
| JP2000341236A (en) | Ofdm signal receiver, ofdm signal communication system and its communication control method | |
| CN109691048B (en) | Transmitter and method for formatting transmission data into frame structure | |
| CN108880777A (en) | Sounding Reference Signal suitable for UFMC waveform sends and receives method | |
| Cho et al. | Symbol timing synchronization for IEEE 802.11 n WLAN systems |
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 |