WO2015139590A1 - 一种频偏估计和补偿的方法及装置 - Google Patents

一种频偏估计和补偿的方法及装置 Download PDF

Info

Publication number
WO2015139590A1
WO2015139590A1 PCT/CN2015/074292 CN2015074292W WO2015139590A1 WO 2015139590 A1 WO2015139590 A1 WO 2015139590A1 CN 2015074292 W CN2015074292 W CN 2015074292W WO 2015139590 A1 WO2015139590 A1 WO 2015139590A1
Authority
WO
WIPO (PCT)
Prior art keywords
frequency offset
signal
pilot
offset estimation
estimation
Prior art date
Application number
PCT/CN2015/074292
Other languages
English (en)
French (fr)
Inventor
张亚文
刘龙
李琼
Original Assignee
电信科学技术研究院
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 电信科学技术研究院 filed Critical 电信科学技术研究院
Publication of WO2015139590A1 publication Critical patent/WO2015139590A1/zh

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
    • H04L27/2647—Arrangements specific to the receiver only
    • H04L27/2655—Synchronisation arrangements
    • H04L27/2689—Link with other circuits, i.e. special connections between synchronisation arrangements and other circuits for achieving synchronisation
    • H04L27/2695—Link with other circuits, i.e. special connections between synchronisation arrangements and other circuits for achieving synchronisation with channel estimation, e.g. determination of delay spread, derivative or peak tracking
    • 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
    • H04L27/2657—Carrier synchronisation
    • 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
    • H04L27/2668—Details of algorithms
    • H04L27/2681—Details of algorithms characterised by constraints
    • H04L27/2682—Precision
    • 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
    • H04L27/2668—Details of algorithms
    • H04L27/2681—Details of algorithms characterised by constraints
    • H04L27/2686—Range of frequencies or delays tested

Definitions

  • the present invention relates to the field of wireless communication technologies, and in particular, to a method and apparatus for frequency offset estimation and compensation.
  • the high-speed railway currently operates at a speed of 300 kilometers per hour (km/h) and may develop to 500km/h in the future.
  • High-speed railway has obvious characteristics: high train running speed, long running distance and complicated geographical environment.
  • existing cellular mobile communication technologies will be limited, the quality of voice communication services will be greatly reduced, and even information islands in high-speed railway environments will emerge.
  • OFDM Orthogonal Frequency Division Multiplexing
  • the existing frequency offset estimation method is to perform frequency offset estimation by frequency domain pilot channel estimation correlation.
  • the pilot signal interval of two time slots in the same subframe is 0.5 ms.
  • the pilot channel estimation difference for each time slot is only caused by the Doppler frequency offset.
  • the frequency offset estimation can be performed by the difference of the pilot channel estimates of the two slots.
  • the formula for the frequency offset estimation is as follows:
  • H 1 represents a frequency domain pilot channel estimate of a previous time slot in the subframe
  • H 2 represents a frequency domain pilot channel estimate of a subsequent time slot in the subframe
  • N sc represents a length of the pilot channel estimation sequence
  • ⁇ t represents the time interval of the pilot signals of two time slots
  • the value of ⁇ t is 0.5 ms.
  • the phase difference of the pilot signals representing the two slots, and angle(*) is a function of the phase.
  • the calculated phase difference ⁇ can only be distinguished within the range of 2 ⁇ .
  • the range of values of ⁇ is limited to (- ⁇ , ⁇ ), and the phase difference exceeding this range is estimated to be a corresponding value of the periodic cycle in the range of (- ⁇ , ⁇ ). Therefore, according to the formula
  • the calculated frequency offset estimation result f d can only be distinguished within the range of 2000 Hz. Taking the value range of ⁇ (- ⁇ , ⁇ ) as an example, the frequency offset estimation range is (-1000Hz, 1000Hz). When the Doppler frequency offset exceeds this range, it is limited by the phase difference period cycle and cannot be accurate. Estimate the correct frequency offset result.
  • the existing frequency offset estimation method is not suitable for a high speed railway environment.
  • a method of frequency offset estimation and compensation comprising:
  • the first frequency offset estimation can obtain a larger frequency offset range.
  • a second frequency offset estimation is then performed by pilot channel estimation of the pilot symbols of the two slots to compensate for the results of the first frequency offset estimation.
  • the signal is obtained from a timing position of at least one OFDM symbol in the subframe in which the received signal is located and a predetermined offset before the timing position, and the first frequency offset estimation is performed by using the acquired signal, specifically by the following manner achieve:
  • the first frequency offset estimation is performed according to the phase difference.
  • the signal is obtained from a timing position of at least one OFDM symbol in the subframe in which the signal is received and a predetermined offset before the timing position, and the first frequency offset estimation is performed by using the acquired signal, specifically
  • the first frequency offset estimation is performed based on the phase difference.
  • pilot channel estimation is performed on the received signal, and a second frequency offset estimation is performed according to the pilot channel estimation result, and the first frequency offset estimation is performed by using the second frequency offset estimation.
  • the result is compensated, one of the implementations can be:
  • the sum of the first frequency offset estimation result and the second frequency offset estimation result is used as the final frequency offset estimation result.
  • the pilot signal is estimated on the received signal, and the second frequency offset estimation is performed according to the pilot channel estimation result, and the result of the first frequency offset estimation is compensated by the second frequency offset estimation, and the other One implementation can be:
  • the second frequency offset estimation is performed according to the phase difference in which the value range is determined, and the second frequency offset estimation result is finally used.
  • the frequency offset estimation results are obtained.
  • pilot channel estimation is performed on the received signal, and a second frequency offset estimation is performed according to the pilot channel estimation result, and the result of the first frequency offset estimation is compensated by the second frequency offset estimation, where
  • One implementation can be:
  • the frequency offset compensation is performed by an interpolation method according to the pilot channel estimation result of the pilot signal of one slot and the compensated pilot channel estimation result of the pilot signal of another slot.
  • an embodiment of the present invention provides a device for estimating and compensating frequency offset, including:
  • a first frequency offset estimation module configured to acquire a signal from a timing position of at least one OFDM symbol in a subframe in which the received signal is located and a predetermined offset before the timing position, and perform the first frequency offset estimation by using the acquired signal
  • the length of the predetermined offset is less than the cyclic prefix length of the received signal
  • a second frequency offset estimation module configured to perform pilot channel estimation on the received signal, perform a second frequency offset estimation according to the pilot channel estimation result, and perform a first frequency offset estimation result by using the second frequency offset estimation make up.
  • the first frequency offset estimation can obtain a larger frequency offset range.
  • a second frequency offset estimation is then performed by pilot channel estimation of the pilot symbols of the two slots to compensate for the results of the first frequency offset estimation.
  • the first frequency offset estimation module is used to:
  • the first frequency offset estimation is performed based on the phase difference.
  • the first frequency offset estimation module is used to:
  • the first frequency offset estimation is performed based on the phase difference.
  • the second frequency offset estimation module is specifically configured to:
  • the sum of the first frequency offset estimation result and the second frequency offset estimation result is used as the final frequency offset estimation result.
  • the second frequency offset estimation module is specifically configured to:
  • the second frequency offset estimation is performed according to the phase difference in which the value range is determined, and the second frequency offset estimation result is used as the final frequency offset estimation result.
  • the second frequency offset estimation module is specifically configured to:
  • the frequency offset compensation is performed by an interpolation method according to the pilot channel estimation result of the pilot signal of one slot and the compensated pilot channel estimation result of the pilot signal of another slot.
  • the embodiment of the present invention provides another apparatus for frequency offset estimation and compensation, including:
  • a processor configured to execute a computer program that acquires a signal from a timing position of at least one OFDM symbol in a subframe in which the received signal is located and a predetermined offset before the timing position, and utilizes the acquired
  • the signal performs a first frequency offset estimation, the length of the predetermined offset is not greater than the cyclic prefix length of the received signal; the pilot channel is estimated for the received signal, and the second frequency offset estimation is performed according to the pilot channel estimation result,
  • the secondary frequency offset estimation compensates for the result of the first frequency offset estimation;
  • a memory configured to hold code of the above computer program.
  • the first frequency offset estimation can obtain a larger frequency offset range.
  • a second frequency offset estimation is then performed by pilot channel estimation of the pilot symbols of the two slots to compensate for the results of the first frequency offset estimation.
  • FIG. 1 is a flowchart of a method according to an embodiment of the present invention
  • FIG. 2 is a schematic diagram of a device according to an embodiment of the present invention.
  • FIG. 3 is a schematic diagram of another apparatus provided by the implementation of the present invention.
  • GSM Global System of Mobile communication
  • CDMA Code Division Multiple Access
  • WCDMA Wideband Code Division Multiple Access
  • GPRS General Packet Radio Service
  • LTE Long Term Evolution
  • LTE-A Advanced Long Term Evolution
  • UMTS Universal Mobile Telecommunication System
  • the user equipment includes but is not limited to a mobile station (Mobile Station, MS), a mobile terminal (Mobile Terminal), a mobile phone (Mobile Telephone), a mobile phone (handset). And portable devices, etc., the user equipment can communicate with one or more core networks via a Radio Access Network (RAN), for example, the user equipment can be a mobile phone (or "cellular"
  • RAN Radio Access Network
  • the user equipment can be a mobile phone (or "cellular"
  • the telephone device, the computer with wireless communication function, etc., the user equipment can also be a mobile device that is portable, pocket-sized, handheld, built-in, or in-vehicle.
  • a base station may refer to a device in an access network that communicates with a wireless terminal over one or more sectors over an air interface.
  • the base station can be used to convert the received air frame to the IP packet as a router between the wireless terminal and the rest of the access network, wherein the remainder of the access network can include an Internet Protocol (IP) network.
  • IP Internet Protocol
  • the base station can also coordinate attribute management of the air interface.
  • the base station may be a Base Transceiver Station (BTS) in GSM or CDMA, or may be a base station (NodeB) in WCDMA, or may be an evolved base station in LTE (NodeB or eNB or e-NodeB, evolutional Node B), the invention is not limited.
  • BTS Base Transceiver Station
  • NodeB base station
  • NodeB evolved base station
  • LTE Long Term Evolutional Node B
  • Embodiments of the present invention provide an implementation scheme of frequency offset estimation and compensation with a larger estimation range.
  • the frequency offset is first estimated by the received signal including the cyclic prefix (CP), and in the channel estimation phase, two time slots are reused. Pilot channel estimation, second estimation or compensation of the frequency offset.
  • CP cyclic prefix
  • the frequency offset estimation and compensation method provided by the embodiment of the present invention is as shown in FIG. 1 , and specifically includes the following operations:
  • Step 100 Acquire a signal from a timing position of at least one OFDM symbol in a subframe in which the signal is received and a predetermined offset before the timing position, and perform first frequency offset estimation using the acquired signal, and the predetermined offset
  • the length is not greater than the CP length of the received signal.
  • Step 110 Perform pilot channel estimation on the received signal, perform a second frequency offset estimation according to the pilot channel estimation result, and compensate the first frequency offset estimation result by using the second frequency offset estimation.
  • the first frequency offset estimation can obtain a larger frequency offset range.
  • a second frequency offset estimation is then performed by pilot channel estimation of the pilot symbols of the two slots to compensate for the results of the first frequency offset estimation.
  • step 100 there are various implementations of step 100 in the embodiment of the present invention, and two preferred implementations are exemplified below.
  • step 100 A preferred implementation of step 100 is as follows:
  • the specific implementation manner of acquiring the frequency domain received signal may be: acquiring an OFDM symbol from a timing position of the OFDM symbol where the at least one pilot signal in the subframe is located and a predetermined offset before the timing position; The OFDM symbol is subjected to FFT transform to obtain a frequency domain signal; and the frequency domain received signal (ie, the signal transmitted by the transmitting end) is obtained from the acquired frequency domain signal according to the frequency domain resource position occupied by the transmitting end of the received signal.
  • the frequency domain receiving signal is obtained from the obtained frequency domain signal, specifically: in the frequency domain signal, the signal of the remaining position except the frequency domain resource position occupied by the receiving signal receiving end is set to zero, and the frequency domain receiving signal is obtained.
  • the length of ⁇ n is greater than 0, and is not greater than the length of the CP of the received signal.
  • the specific value may be determined according to actual conditions, and it is required to ensure that the intercepted OFDM symbol does not include the delayed signal of the previous OFDM symbol.
  • the signal of the remaining frequency position other than the frequency domain resource position of the receiving signal in the obtained frequency domain signal S is zeroed to obtain the frequency domain receiving signal.
  • the obtained frequency domain signal S f2 is zeroed at a signal other than the frequency domain resource position of the receiving signal receiving end, and the frequency domain receiving signal is obtained.
  • Ts 1 / frequency domain sampling interval * N FFT .
  • N FFT is the sequence length for performing FFT transform.
  • the first frequency offset estimation is performed based on the OFDM symbol in which the two pilot signals are located on the single antenna
  • the first frequency offset estimation is performed based on the OFDM symbol in which the single pilot signal is located on the multiple antennas, or based on the two antennas on the multiple antennas
  • the OFDM symbol in which the frequency signal is located performs the first frequency offset estimation, and may refer to the processing procedure of the OFDM symbol in which the pilot signal of the single antenna is located. But in calculating the phase difference When the phase difference obtained on each antenna and each OFDM symbol is averaged, the phase difference used for the first frequency offset estimation is obtained.
  • the frequency domain received signals obtained by the timing positions of the antennas and the OFDM symbols may be averaged, and the frequency domain received signals acquired at the ⁇ n point before the timing positions of the antennas and the OFDM symbols are averaged, and the phase is calculated using the average result. difference Other ways to determine the phase difference The invention is not limited thereto.
  • step 100 The preferred implementation of step 100 is as follows:
  • the specific implementation manner of acquiring the time domain received signal may be: acquiring an OFDM symbol from a timing position of at least one OFDM symbol in the subframe and a predetermined offset before the timing position; performing FFT transformation on the acquired OFDM symbol Obtaining a frequency domain signal, and obtaining, according to the frequency domain resource position occupied by the transmitting end of the receiving signal, a signal transmitted by the transmitting end from a frequency domain signal obtained by the timing position of the OFDM symbol and a predetermined offset before the timing position; The timing position of the OFDM symbol and the signal transmitted by the transmitting end at a predetermined offset before the timing position are converted into a time domain signal.
  • the signal of the remaining position other than the frequency domain resource position of the receiving signal receiving end of the received frequency domain signal S f1 is zeroed to obtain the frequency domain receiving signal.
  • the obtained frequency domain signal S f2 is zeroed at a signal other than the frequency domain resource position of the signal receiving end of the receiving signal to obtain a frequency domain receiving signal.
  • Ts 1 / frequency domain sampling interval * N FFT .
  • the first frequency offset estimation is performed based on the OFDM symbol in which the two pilot signals are located on the single antenna
  • the first frequency offset estimation is performed based on the OFDM symbol in which the single pilot signal is located on the multiple antennas, or based on the two antennas on the multiple antennas
  • the OFDM symbol in which the frequency signal is located performs the first frequency offset estimation, and may refer to the processing procedure of the OFDM symbol in which the pilot signal of the single antenna is located. But in calculating the phase difference When the phase difference obtained on each antenna and each OFDM symbol is averaged, the phase difference used for the first frequency offset estimation is obtained.
  • the frequency domain received signals obtained by the timing positions of the antennas and the OFDM symbols may be averaged, and the frequency domain received signals acquired at the ⁇ n point before the timing positions of the antennas and the OFDM symbols are averaged, and the phase is calculated using the average result. difference Other ways to determine the phase difference The invention is not limited thereto.
  • step 110 in the embodiment of the present invention is various, and two preferred implementations are exemplified below.
  • step 110 is as follows:
  • pilot channel estimation on the pilot signals of the two slots in the foregoing subframe using the result of the first frequency offset estimation to compensate the pilot channel estimation result of the pilot signal of one of the slots; according to a time slot
  • the pilot channel estimation result of the pilot signal and the compensated pilot channel estimation result of the pilot signal of another time slot perform a second frequency offset estimation; the first frequency offset estimation result and the second frequency offset
  • the sum of the estimated results is used as the final frequency offset estimation result.
  • pilot channel of the two slots of the foregoing subframe is subjected to pilot channel estimation, that is, pilot channel estimation is performed on the received signal.
  • the result of the first frequency offset estimation is corrected by the second frequency offset estimation, and the final frequency offset estimation result is obtained, that is, the second frequency offset estimation result is summed with the first frequency offset estimation result, and the And the result as the final frequency offset Estimated results.
  • f d,h is the second frequency offset estimation result
  • ⁇ t is the time interval of the pilot signals of two time slots, the specific value is 0.5 milliseconds
  • N sc is the length of the pilot channel estimation sequence
  • H slot1 ( n) the nth element of the pilot channel estimation result (sequence) H slot1 of the pilot signal of the previous time slot of the above subframe
  • H slot 2 (n) is the nth element of the pilot channel estimation result (sequence) H slot 2 of the pilot signal of the subsequent slot of the above subframe
  • Indicates that the first frequency offset estimation result f d is used, and CP compensates H slot 2 (n).
  • the above formula illustrates the use of the first frequency offset estimation result to compensate the pilot channel estimation result of the pilot signal of the subsequent time slot of the foregoing subframe as an example. It should be noted that the first frequency offset may also be used.
  • the estimation result compensates for the pilot channel estimation result of the pilot signal of the previous slot of the above subframe.
  • the second frequency offset estimation result is averaged, and then the averaged result is compared with the first frequency offset estimation result. As a result of the final frequency offset estimation.
  • step 110 is as follows:
  • pilot channel estimation on the pilot signals of the two slots in the foregoing subframe using the result of the first frequency offset estimation to compensate the pilot channel estimation result of the pilot signal of one of the slots; according to a time slot
  • the pilot channel estimation result of the pilot signal and the compensated pilot channel estimation result of the pilot signal of another time slot are subjected to frequency offset compensation by an interpolation method.
  • Pilot channel estimation is performed on pilot signals of two slots in the above subframe; using the result f d of the first frequency offset estimation , the CP compensates the pilot channel estimation result of the pilot signal of one of the slots. For example, the pilot channel estimation result H slot2 of the latter time slot is compensated for the frequency offset f d, CP , and the compensated channel estimation result is obtained.
  • the channel estimation result on all OFDM symbols in the latter slot is inversely compensated for the frequency offset f d, CP , Get the final channel estimate It includes further estimates and compensation for the Doppler shift.
  • the Doppler frequency offset to be compensated is f d, CP .
  • the CP determines the range of the phase difference of the pilot signals of the two time slots; performs the second frequency offset estimation according to the phase difference of the determined value range, and uses the second frequency offset estimation result as the final frequency offset estimation result.
  • the pilot channel estimation is performed on the pilot signals of the two slots in the foregoing subframe, and the principle of determining the phase difference of the pilot signals of the two slots according to the pilot channel estimation result is as follows:
  • ⁇ is the phase difference of the pilot signals of two time slots, and other parameters are explained by referring to the foregoing formula.
  • the phase difference of the pilot signals of the two time slots may be determined according to the pilot channel estimation result, and then the range of the phase difference is determined, and the phase difference is corrected according to the determined value range, and the phase difference is performed according to the corrected phase difference.
  • the phase difference of the pilot signals of the two time slots may be determined according to the result of the first frequency offset estimation, and then the phase difference is determined according to the value range and the pilot channel estimation result, according to the determined phase difference. Perform a second frequency offset estimation. For example, if the first frequency offset estimation result is 1350 Hz, and the determined phase difference has a value range of ⁇ 2 ⁇ , then the phase difference is determined to be 1.2 ⁇ .
  • the embodiment of the present invention provides a device for estimating and compensating for frequency offset, as shown in FIG. 2, including:
  • the first frequency offset estimation module 201 is configured to acquire a signal from a timing position of the at least one OFDM symbol in the subframe where the received signal is located and a predetermined offset before the timing position, and perform the first frequency offset by using the acquired signal. Estimating that the length of the predetermined offset is less than the cyclic prefix length of the received signal;
  • the second frequency offset estimation module 202 is configured to perform pilot channel estimation on the received signal, and estimate the junction according to the pilot channel. If the second frequency offset estimation is performed, the result of the first frequency offset estimation is compensated by the second frequency offset estimation.
  • the first frequency offset estimation can obtain a larger frequency offset range.
  • a second frequency offset estimation is then performed by pilot channel estimation of the pilot symbols of the two slots to compensate for the results of the first frequency offset estimation.
  • the first frequency offset estimation module 201 is configured to:
  • the first frequency offset estimation is performed based on the phase difference.
  • the first frequency offset estimation module 201 is configured to:
  • the first frequency offset estimation is performed based on the phase difference.
  • the second frequency offset estimation module 202 is specifically configured to:
  • the sum of the first frequency offset estimation result and the second frequency offset estimation result is used as the final frequency offset estimation result.
  • the second frequency offset estimation module 202 is specifically configured to:
  • the second frequency offset estimation is performed according to the phase difference in which the value range is determined, and the second frequency offset estimation result is used as the final frequency offset estimation result.
  • the second frequency offset estimation module 202 is specifically configured to:
  • the frequency offset compensation is performed by an interpolation method according to the pilot channel estimation result of the pilot signal of one slot and the compensated pilot channel estimation result of the pilot signal of another slot.
  • the embodiment of the present invention provides another device for frequency offset estimation and compensation, as shown in FIG. 3, including:
  • the processor 301 is configured to execute a computer program having the following functions: acquiring a signal from a timing position of at least one OFDM symbol in a subframe in which the signal is received and a predetermined offset before the timing position, and utilizing The acquired signal performs a first frequency offset estimation, the length of the predetermined offset is smaller than the cyclic prefix length of the received signal; the pilot channel is estimated for the received signal, and the second frequency offset estimation is performed according to the pilot channel estimation result, The second frequency offset estimation compensates for the result of the first frequency offset estimation;
  • Memory 302 which is configured to hold the code of the above computer program.
  • the first frequency offset estimation can obtain a larger frequency offset range.
  • a second frequency offset estimation is then performed by pilot channel estimation of the pilot symbols of the two slots to compensate for the results of the first frequency offset estimation.
  • embodiments of the present invention can be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or a combination of software and hardware. Moreover, the invention can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) including computer usable program code.
  • computer-usable storage media including but not limited to disk storage, CD-ROM, optical storage, etc.
  • These computer program instructions can also be stored in a particular computer capable of booting a computer or other programmable data processing device In a computer readable memory that operates in a computer readable memory, causing instructions stored in the computer readable memory to produce an article of manufacture comprising instruction means implemented in a block or in a flow or a flow diagram and/or block diagram of the flowchart The functions specified in the boxes.
  • These computer program instructions can also be loaded onto a computer or other programmable data processing device such that a series of operational steps are performed on a computer or other programmable device to produce computer-implemented processing for execution on a computer or other programmable device.
  • the instructions provide steps for implementing the functions specified in one or more of the flow or in a block or blocks of a flow diagram.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)
  • Synchronisation In Digital Transmission Systems (AREA)

Abstract

本发明公开了一种频偏估计和补偿的方法及装置。其方法包括：从接收信号所在子帧中的至少一个正交频分复用OFDM符号的定时位置及所述定时位置之前的预定偏移量处获取信号，并利用获取的信号进行第一次频偏估计，所述预定偏移量的长度不大于于所述接收信号的循环前缀长度；对所述接收信号进行导频信道估计，并根据导频信道估计结果进行第二次频偏估计，通过第二次频偏估计对第一次频偏估计的结果进行补偿。本发明实施例提供的技术方案，可估计的频偏范围扩大，准确性较好，适用于高速及高铁场景。

Description

一种频偏估计和补偿的方法及装置
本申请要求在2014年3月21日提交中国专利局、申请号为201410109805.X、发明名称为“一种频偏估计和补偿的方法及装置”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本发明涉及无线通信技术领域，尤其涉及一种频偏估计和补偿的方法及装置。
背景技术
高速铁路目前的运行速度为300千米每小时(km/h)，未来可能发展到500km/h。高速铁路具有比较明显的特点：列车运行速度高，运行距离长、穿越地理环境复杂等。在高速铁路环境下，现有的蜂窝移动通信技术将受到限制，语音通信的服务质量大大下降，甚至出现高速铁路环境下的信息孤岛。
对于正交频分复用(Orthogonal Frequency Division Multiplexing，OFDM)技术而言，高速移动产生的多普勒频散会破坏OFDM子载波间正交性，产生子载波间干扰。子载波间干扰将严重影响信道估计的准确性，进而导致OFDM***性能急剧下降。因此如何在高速移动环境下准确地进行频偏估计是OFDM***亟需解决的关键性难题之一。
现有的频偏估计方法，是通过频域导频信道估计相关进行频偏估计。具体的，同一子帧中两个时隙的导频信号间隔为0.5ms，在实际传输过程中，假设传输信道在这一时间间隔内的衰落特性基本不变，那么可以认为同一子帧中两个时隙的导频信道估计差异仅由多普勒频偏造成。通过两个时隙的导频信道估计的差异，可进行频偏估计。频偏估计的公式如下：
Figure PCTCN2015074292-appb-000001
其中，H1表示子帧中前一个时隙的频域导频信道估计，H2表示子帧中后一个时隙的频域导频信道估计，Nsc表示导频信道估计序列的长度，△t表示两个时隙的导频信号 的时间间隔，△t的取值为0.5ms，
Figure PCTCN2015074292-appb-000002
表示两个时隙的导频信号的相位差，angle(*)为求相位的函数。
现有的频偏估计方法，通过公式
Figure PCTCN2015074292-appb-000003
计算得到的相位差φ，仅能在2π范围内进行区分。例如，将φ的取值范围限定在(-π,π]，超过这一范围的相位差，其估计结果为(-π,π]范围内的周期循环对应值。因此，根据公式
Figure PCTCN2015074292-appb-000004
计算得到频偏估计结果fd仅能在2000Hz范围内进行区分。以φ∈(-π,π]的取值范围为例，频偏估计范围为(-1000Hz,1000Hz]。当多普勒频偏超过这一范围时，受相位差周期循环的限制，不能准确估计得到正确的频偏结果。
因此，现有的频偏估计方法不适用于高速铁路环境。
发明内容
本发明的目的是提供一种频偏估计和补偿的方法及装置，以解决现有的频偏估计范围较小的问题。
本发明的目的是通过以下技术方案实现的：
一种频偏估计和补偿的方法，包括：
从接收信号所在子帧中的至少一个OFDM符号的定时位置及该定时位置之前的预定偏移量处获取信号，并利用获取的信号进行第一次频偏估计，预定偏移量的长度小于接收信号的循环前缀长度；
对上述接收信号进行导频信道估计，并根据导频信道估计结果进行第二次频偏估计，通过第二次频偏估计对第一次频偏估计的结果进行补偿。
由于OFDM符号的定时位置及之前的预定偏移量的时域间隔远远小于两个时隙的导频符号的时域间隔，因此，第一次频偏估计能够获得较大的频偏范围，然后通过两个时隙的导频符号的导频信道估计进行第二次频偏估计，以便对第一次频偏估计的结果进行补偿。本发明实施例提供的技术方案，可估计的频偏范围扩大，准确性较好，适用于高速及高铁场景。
较佳地，从接收信号所在子帧中的至少一个OFDM符号的定时位置及该定时位置之前的预定偏移量处获取信号，并利用获取的信号进行第一次频偏估计，具体通过以下方式实现：
从该子帧中的至少一个导频信号所在的OFDM符号的定时位置及该定时位置之前的预定偏移量处获取频域接收信号；
确定上述OFDM符号的定时位置及该定时位置之前的预定偏移量处的频域接收信号的相位差；
根据所述相位差进行第一次频偏估计。
较佳地，从接收信号所在子帧中的至少一个OFDM符号的定时位置及所述定时位置之前的预定偏移量处获取信号，并利用获取的信号进行第一次频偏估计，具体可以通过以下方式实现：
从上述子帧中的至少一个OFDM符号的定时位置及该定时位置之前的预定偏移量处获取时域接收信号；
截取上述OFDM符号的定时位置的时域接收信号的后预定偏移量长度的时域信号，并截取该定时位置之前的预定偏移量处的时域接收信号的前预定偏移量长度的时域信号；
确定截取的时域信号之间的相位差；
根据该相位差进行第一次频偏估计。
基于上述任意实施例，较佳地，对上述接收信号进行导频信道估计，并根据导频信道估计结果进行第二次频偏估计，通过第二次频偏估计对第一次频偏估计的结果进行补偿，其一种实现方式可以是：
对所述子帧中两个时隙的导频信号进行导频信道估计；
使用第一次频偏估计的结果对其中一个时隙的导频信号的导频信道估计结果进行补偿；
根据一个时隙的导频信号的导频信道估计结果和另一个时隙的导频信号的补偿后的导频信道估计结果进行第二次频偏估计；
将第一次频偏估计结果与第二次频偏估计结果之和，作为最终的频偏估计结果。
较佳地，对上述接收信号进行导频信道估计，并根据导频信道估计结果进行第二次频偏估计，通过第二次频偏估计对第一次频偏估计的结果进行补偿，其另一种实现方式可以是：
对上述子帧中两个时隙的导频信号进行导频信道估计；
根据导频信道估计结果确定两个时隙的导频信号的相位差；
根据第一次频偏估计的结果确定两个时隙的导频信号的相位差的取值范围；
根据确定了取值范围的相位差进行第二次频偏估计，将第二次频偏估计结果作为最终 的频偏估计结果。
较佳地，对上述接收信号进行导频信道估计，并根据导频信道估计结果进行第二次频偏估计，通过第二次频偏估计对第一次频偏估计的结果进行补偿，其又一种实现方式可以是：
对所述子帧中两个时隙的导频信号进行导频信道估计；
使用第一次频偏估计的结果对其中一个时隙的导频信号的导频信道估计结果进行补偿；
根据一个时隙的导频信号的导频信道估计结果和另一个时隙的导频信号的补偿后的导频信道估计结果通过插值方法进行频偏补偿。
基于与方法同样的发明构思，本发明实施例提供一种频偏估计和补偿的装置，包括：
第一频偏估计模块，用于从接收信号所在子帧中的至少一个OFDM符号的定时位置及该定时位置之前的预定偏移量处获取信号，并利用获取的信号进行第一次频偏估计，预定偏移量的长度小于接收信号的循环前缀长度；
第二频偏估计模块，用于对接收信号进行导频信道估计，并根据导频信道估计结果进行第二次频偏估计，通过第二次频偏估计对第一次频偏估计的结果进行补偿。
由于OFDM符号的定时位置及之前的预定偏移量的时域间隔远远小于两个时隙的导频符号的时域间隔，因此，第一次频偏估计能够获得较大的频偏范围，然后通过两个时隙的导频符号的导频信道估计进行第二次频偏估计，以便对第一次频偏估计的结果进行补偿。本发明实施例提供的技术方案，可估计的频偏范围扩大，准确性较好，适用于高速及高铁场景。
较佳地，第一频偏估计模块用于：
从上述子帧中的至少一个导频信号所在的OFDM符号的定时位置及该定时位置之前的预定偏移量处获取频域接收信号；
确定上述OFDM符号的定时位置及该定时位置之前的预定偏移量处的频域接收信号的相位差；
根据该相位差进行第一次频偏估计。
较佳地，第一频偏估计模块用于：
从上述子帧中的至少一个OFDM符号的定时位置及该定时位置之前的预定偏移量处获取时域接收信号；
截取上述OFDM符号的定时位置的时域接收信号的后预定偏移量长度的时域信号，并截取该定时位置之前的预定偏移量处的时域信号的前预定偏移量长度的时域信号；
确定截取的时域信号之间的相位差；
根据该相位差进行第一次频偏估计。
基于上述任意装置实施例，较佳地，第二频偏估计模块具体用于：
对上述子帧中两个时隙的导频信号进行导频信道估计；
使用第一次频偏估计的结果对其中一个时隙的导频信号的导频信道估计结果进行补偿；
根据一个时隙的导频信号的导频信道估计结果和另一个时隙的导频信号的补偿后的导频信道估计结果进行第二次频偏估计；
将第一次频偏估计结果与第二次频偏估计结果之和，作为最终的频偏估计结果。
较佳地，第二频偏估计模块具体用于：
对上述子帧中两个时隙的导频信号进行导频信道估计；
根据导频信道估计结果确定两个时隙的导频信号的相位差；
根据第一次频偏估计的结果确定两个时隙的导频信号的相位差的取值范围；
根据确定了取值范围的相位差进行第二次频偏估计，将第二次频偏估计结果作为最终的频偏估计结果。
较佳地，第二频偏估计模块具体用于：
对所述子帧中两个时隙的导频信号进行导频信道估计；
使用第一次频偏估计的结果对其中一个时隙的导频信号的导频信道估计结果进行补偿；
根据一个时隙的导频信号的导频信道估计结果和另一个时隙的导频信号的补偿后的导频信道估计结果通过插值方法进行频偏补偿。
基于与方法同样的发明构思，本发明实施例提供另一种频偏估计和补偿的装置，包括：
处理器，该处理器被配置为执行具有下列功能的计算机程序：从接收信号所在子帧中的至少一个OFDM符号的定时位置及该定时位置之前的预定偏移量处获取信号，并利用获取的信号进行第一次频偏估计，预定偏移量的长度不大于接收信号的循环前缀长度；对接收信号进行导频信道估计，并根据导频信道估计结果进行第二次频偏估计，通过第二次频偏估计对第一次频偏估计的结果进行补偿；
存储器，该存储器被配置为保存上述计算机程序的代码。
由于OFDM符号的定时位置及之前的预定偏移量的时域间隔远远小于两个时隙的导频符号的时域间隔，因此，第一次频偏估计能够获得较大的频偏范围，然后通过两个时隙的导频符号的导频信道估计进行第二次频偏估计，以便对第一次频偏估计的结果进行补偿。本发明实施例提供的技术方案，可估计的频偏范围扩大，准确性较好，适用于高速及高铁场景。
附图说明
图1为本发明实施例提供的方法流程图；
图2为本发明实施例提供的一种装置示意图；
图3为本发明实施提供的另一种装置示意图。
具体实施方式
为使本发明实施例的目的、技术方案和优点更加清楚，下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有作出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。
应理解，本发明的技术方案可以应用于各种通信***，例如：全球移动通讯(Global System of Mobile communication，GSM)***、码分多址(Code Division Multiple Access，CDMA)***、宽带码分多址(Wideband Code Division Multiple Access，WCDMA)***、通用分组无线业务(General Packet Radio Service，GPRS)、长期演进(Long Term Evolution，LTE)***、先进的长期演进(Advanced long term evolution，LTE-A)***、通用移动通信***(Universal Mobile Telecommunication System，UMTS)等。
还应理解，在本发明实施例中，用户设备(User Equipment，UE)包括但不限于移动台(Mobile Station，MS)、移动终端(Mobile Terminal)、移动电话(Mobile Telephone)、手机(handset)及便携设备(portable equipment)等，该用户设备可以经无线接入网(Radio Access Network，RAN)与一个或多个核心网进行通信，例如，用户设备可以是移动电话(或称为“蜂窝”电话)、具有无线通信功能的计算机等，用户设备还可以是便携式、袖珍式、手持式、计算机内置的或者车载的移动装置。
在本发明实施例中，基站(例如，接入点)可以是指接入网中在空中接口上通过一个或多个扇区与无线终端通信的设备。基站可用于将收到的空中帧与IP分组进行相互转换，作为无线终端与接入网的其余部分之间的路由器，其中接入网的其余部分可包括网际协议(IP)网络。基站还可协调对空中接口的属性管理。例如，基站可以是GSM或CDMA中的基站(Base Transceiver Station，BTS)，也可以是WCDMA中的基站(NodeB)，还可以是LTE中的演进型基站(NodeB或eNB或e-NodeB，evolutional Node B)，本发明并不限定。
本发明实施例提供一种具有较大估计范围的频偏估计和补偿的实现方案。首先通过包含循环前缀(CP)的接收信号对频偏进行第一次估计，在信道估计阶段，再利用两个时隙 的导频信道估计，对频偏进行第二次估计或补偿。
下面将结合附图，对本发明实施例提供的技术方案进行详细说明。
本发明实施例提供的频偏估计和补偿方法如图1所示，具体包括如下操作：
步骤100、从接收信号所在子帧中的至少一个OFDM符号的定时位置及该定时位置之前的预定偏移量处获取信号，并利用获取的信号进行第一次频偏估计，预定偏移量的长度不大于接收信号的CP长度。
步骤110、对上述接收信号进行导频信道估计，并根据导频信道估计结果进行第二次频偏估计，通过第二次频偏估计对第一次频偏估计的结果进行补偿。
由于OFDM符号的定时位置及之前的预定偏移量的时域间隔远远小于两个时隙的导频符号的时域间隔，因此，第一次频偏估计能够获得较大的频偏范围，然后通过两个时隙的导频符号的导频信道估计进行第二次频偏估计，以便对第一次频偏估计的结果进行补偿。本发明实施例提供的技术方案，可估计的频偏范围扩大，准确性较好，适用于高速及高铁场景。
本发明实施例步骤100的实现方式有多种，下面例举其中两种优选的实现方式。
步骤100的优选实现方式一：
从上述子帧中的至少一个导频信号所在的OFDM符号的定时位置及该定时位置之前的预定偏移量处获取频域接收信号；确定上述OFDM符号的定时位置及该定时位置之前的预定偏移量处的频域接收信号的相位差；根据该相位差进行第一次频偏估计。
其中，获取频域接收信号的具体实现方式可以是：从上述子帧中的至少一个导频信号所在的OFDM符号的定时位置及该定时位置之前的预定偏移量处获取OFDM符号；对获取的OFDM符号进行FFT变换，得到频域信号；根据接收信号发送端所占频域资源位置，从获取的频域信号中得到频域接收信号(即该发送端传输的信号)。
其中，从获取的频域信号中得到频域接收信号，具体是：将频域信号中，接收信号发送端所占频域资源位置之外的其余位置的信号置零，得到频域接收信号。
以单天线的一个导频信号所在的OFDM符号为例：
从上述子帧中的一个导频信号所在的OFDM符号的定时位置获取OFDM符号，对获取的OFDM符号进行FFT变换，得到频域信号Sf1；将该OFDM符号的定时位置向前△n点(预定偏移量)作为新的OFDM符号起始位置，从该位置获取OFDM符号，对获取的OFDM符号进行FFT变换，得到频域信号Sf2。其中，△n的长度大于0，且不大于接收信号的CP的长度，具体取值可以根据实际情况确定，需要保证截取的OFDM符号不包含上一个OFDM符号的延迟信号。
根据接收信号发送端所占频域资源位置，将获取的频域信号S中接收信号发送端所占频域资源位置之外的其余位置的信号置零，得到频域接收信号
Figure PCTCN2015074292-appb-000005
并将获取的频域信号 Sf2中接收信号发送端所占频域资源位置之外的其余位置的信号置零，得到频域接收信号
Figure PCTCN2015074292-appb-000006
计算
Figure PCTCN2015074292-appb-000007
与
Figure PCTCN2015074292-appb-000008
的共轭相乘
Figure PCTCN2015074292-appb-000009
根据共轭相乘确定
Figure PCTCN2015074292-appb-000010
与
Figure PCTCN2015074292-appb-000011
的相位差
Figure PCTCN2015074292-appb-000012
具体的，可以对共轭相乘的结果求平均，根据平均结果确定相位差，也可以对共轭相乘结果求和，根据求和结果确定相位差。
通过公式
Figure PCTCN2015074292-appb-000013
计算得到第一次频偏估计结果。
其中，Ts是时域采样间隔，Ts＝1/频域采样间隔*NFFT。
其中，NFFT为进行FFT变换的序列长度。
如果基于单天线上两个导频信号所在的OFDM符号进行第一次频偏估计，基于多天线上单个导频信号所在的OFDM符号进行第一次频偏估计，或基于多天线上两个导频信号所在的OFDM符号进行第一次频偏估计，可以参照上述单天线上一个导频信号所在的OFDM符号的处理过程。但在计算相位差
Figure PCTCN2015074292-appb-000014
时，对各天线、各OFDM符号上求得的相位差进行平均，得到进行第一次频偏估计使用的相位差
Figure PCTCN2015074292-appb-000015
也可以对各天线、各OFDM符号的定时位置获取的频域接收信号进行平均，对各天线、各OFDM符号的定时位置之前△n点处获取的频域接收信号进行平均，使用平均结果计算相位差
Figure PCTCN2015074292-appb-000016
还可以采用其他方式确定相位差
Figure PCTCN2015074292-appb-000017
本发明对此不作限定。
步骤100的优选实现方式二：
从上述子帧中的至少一个OFDM符号的定时位置及该定时位置之前的预定偏移量处获取时域接收信号；截取上述OFDM符号的定时位置的时域接收信号的后预定偏移量长度的时域信号，并截取该定时位置之前的预定偏移量处的时域接收信号的前预定偏移量长度的时域信号；确定截取的时域信号之间的相位差；根据该相位差进行第一次频偏估计。
其中，获取时域接收信号的具体实现方式可以是：从上述子帧中的至少一个OFDM符号的定时位置及该定时位置之前的预定偏移量处获取OFDM符号；对获取的OFDM符号进行FFT变换，得到频域信号，根据上述接收信号发送端所占频域资源位置，从上述OFDM符号的定时位置及该定时位置之前的预定偏移量处获取的频域信号中得到发送端传输的信号；将上述OFDM符号的定时位置及该定时位置之前的预定偏移量处的发送端传输的信号转换为时域信号。
以单天线的一个导频信号所在的OFDM符号为例：
从上述子帧中的一个OFDM符号的定时位置获取OFDM符号，对获取的OFDM符号进行FFT变换，得到频域信号Sf1；将该OFDM符号的定时位置向前△n点(预定偏移量)作为新的OFDM符号起始位置，从该位置获取OFDM符号，对获取的OFDM符号进行FFT变换，得到频域信号Sf2。其中，△n的长度大于0，且小于或等于接收信号的CP的长度， 具体取值可以根据实际情况确定，需要保证截取的OFDM符号不包含上一个OFDM符号的延迟信号。
根据接收信号发送端所占频域资源位置，将获取的频域信号Sf1中接收信号发送端所占频域资源位置之外的其余位置的信号置零，得到频域接收信号
Figure PCTCN2015074292-appb-000018
并将获取的频域信号Sf2中接收信号发送端所占频域资源位置之外的其余位置的信号置零，得到频域接收信号
Figure PCTCN2015074292-appb-000019
将
Figure PCTCN2015074292-appb-000020
和
Figure PCTCN2015074292-appb-000021
分别变换到时域得到时域接收信号
Figure PCTCN2015074292-appb-000022
和
Figure PCTCN2015074292-appb-000023
分别截取
Figure PCTCN2015074292-appb-000024
的后△n长的信号
Figure PCTCN2015074292-appb-000025
以及
Figure PCTCN2015074292-appb-000026
的前△n长的信号
Figure PCTCN2015074292-appb-000027
计算
Figure PCTCN2015074292-appb-000028
与
Figure PCTCN2015074292-appb-000029
的共轭相乘
Figure PCTCN2015074292-appb-000030
根据共轭相乘确定
Figure PCTCN2015074292-appb-000031
与
Figure PCTCN2015074292-appb-000032
的相位差
Figure PCTCN2015074292-appb-000033
具体的，可以对共轭相乘的结果求平均，根据平均结果确定相位差，也可以对共轭相乘结果求和，根据求和结果确定相位差。
通过公式
Figure PCTCN2015074292-appb-000034
计算得到第一次频偏估计结果。
其中，Ts是时域采样间隔，Ts＝1/频域采样间隔*NFFT。
如果基于单天线上两个导频信号所在的OFDM符号进行第一次频偏估计，基于多天线上单个导频信号所在的OFDM符号进行第一次频偏估计，或基于多天线上两个导频信号所在的OFDM符号进行第一次频偏估计，可以参照上述单天线上一个导频信号所在的OFDM符号的处理过程。但在计算相位差
Figure PCTCN2015074292-appb-000035
时，对各天线、各OFDM符号上求得的相位差进行平均，得到进行第一次频偏估计使用的相位差
Figure PCTCN2015074292-appb-000036
也可以对各天线、各OFDM符号的定时位置获取的频域接收信号进行平均，对各天线、各OFDM符号的定时位置之前△n点处获取的频域接收信号进行平均，使用平均结果计算相位差
Figure PCTCN2015074292-appb-000037
还可以采用其他方式确定相位差
Figure PCTCN2015074292-appb-000038
本发明对此不作限定。
基于上述任意实施例，本发明实施例步骤110的实现方式有多种，下面例举其中两种优选的实现方式。
步骤110的优选实现方式一：
对上述子帧中两个时隙的导频信号进行导频信道估计；使用第一次频偏估计的结果对其中一个时隙的导频信号的导频信道估计结果进行补偿；根据一个时隙的导频信号的导频信道估计结果和另一个时隙的导频信号的补偿后的导频信道估计结果进行第二次频偏估计；将第一次频偏估计结果与第二次频偏估计结果之和，作为最终的频偏估计结果。
其中，对上述子帧的两个时隙的导频信号进行导频信道估计，即对接收信号进行导频信道估计。
其中，通过第二次频偏估计对第一次频偏估计的结果进行校正，得到最终的频偏估计结果，即将第二次频偏估计结果与第一次频偏估计结果求和，将求和结果作为最终的频偏 估计结果。
其中，第二次频偏估计的原理如下式：
Figure PCTCN2015074292-appb-000039
其中，fd,h为第二次频偏估计结果；△t为两个时隙的导频信号的时间间隔，具体值为0.5毫秒；Nsc为导频信道估计序列的长度，Hslot1(n)为上述子帧的前一个时隙的导频信号的导频信道估计结果(序列)Hslot1的第n个元素；
Figure PCTCN2015074292-appb-000040
为Hslot1(n)的共轭；Hslot2(n)为上述子帧的后一个时隙的导频信号的导频信道估计结果(序列)Hslot2的第n个元素；
Figure PCTCN2015074292-appb-000041
表示使用第一次频偏估计结果fd,CP对Hslot2(n)进行补偿。
上述公式以使用第一次频偏估计结果对上述子帧的后一个时隙的导频信号的导频信道估计结果进行补偿为例进行说明，应当指出的是，也可以使用第一次频偏估计结果对上述子帧的前一个时隙的导频信号的导频信道估计结果进行补偿。
如果采用多根天线接收，则对不同天线上的接收信号进行第二次频偏估计后，将第二次频偏估计结果进行平均，然后将平均所得结果与第一次频偏估计结果之和作为最终的频偏估计结果。
步骤110的优选实现方式二：
对上述子帧中两个时隙的导频信号进行导频信道估计；使用第一次频偏估计的结果对其中一个时隙的导频信号的导频信道估计结果进行补偿；根据一个时隙的导频信号的导频信道估计结果和另一个时隙的导频信号的补偿后的导频信道估计结果通过插值方法进行频偏补偿。
对上述子帧中两个时隙的导频信号进行导频信道估计；使用第一次频偏估计的结果fd,CP对其中一个时隙的导频信号的导频信道估计结果进行补偿。例如，对后一个时隙的导频信道估计结果Hslot2进行频偏fd,CP的补偿，得到补偿后的信道估计结果
Figure PCTCN2015074292-appb-000042
以Hslot1和
Figure PCTCN2015074292-appb-000043
为参考，通过插值方法得到一个子帧中所有OFDM符号上的信道估计结果，以常规CP为例，插值之后的结果为
Figure PCTCN2015074292-appb-000044
对后一个时隙所有OFDM符号上的信道估计结果反向补偿频偏fd,CP，
Figure PCTCN2015074292-appb-000045
得到最终的信道估计
Figure PCTCN2015074292-appb-000046
其中包含了对多普勒频偏的进一步估计和补偿。此外还需要补偿的多普勒频偏为fd,CP。
步骤110的优选实施方式三：
对上述子帧中两个时隙的导频信号进行导频信道估计；根据导频信道估计结果确定两个时隙的导频信号的相位差；根据第一次频偏估计的结果fd,CP确定两个时隙的导频信号的相位差的取值范围；根据确定了取值范围的相位差进行第二次频偏估计，将第二次频偏估计结果作为最终的频偏估计结果。
其中，对上述子帧中的两个时隙的导频信号进行导频信道估计，根据导频信道估计结果确定两个时隙的导频信号的相位差的原理如下式：
Figure PCTCN2015074292-appb-000047
φ为两个时隙的导频信号的相位差，其他参数的解释参照前述公式。
其中，若-1000<fd,CP≤1000，则-π<φ≤π，若-2000<fd,CP≤-1000，则-2π<φ≤-π，若1000<fd,CP≤2000，则π<φ≤2π，依此类推。
通过公式
Figure PCTCN2015074292-appb-000048
计算得到最终的频偏估计结果fd。
其中，可以先根据导频信道估计结果确定两个时隙的导频信号的相位差，然后确定相位差的取值范围，并根据确定的取值范围校正相位差，根据校正的相位差进行第二次频偏估计。例如：确定的相位差为-0.8π，第一次频偏估计的结果为1350Hz，则确定的相位差的取值范围π<φ≤2π，那么，调整相位差为-0.8π+2π＝1.2π。
也可以先根据第一次频偏估计的结果确定两个时隙的导频信号的相位差的取值范围，然后根据该取值范围和导频信道估计结果确定相位差，根据确定的相位差进行第二次频偏估计。例如：第一次频偏估计结果为1350Hz，则确定的相位差的取值范围π<φ≤2π，那么，确定相位差为1.2π。
基于与方法同样的发明构思，本发明实施例提供一种频偏估计和补偿的装置，如图2所示，包括：
第一频偏估计模块201，用于从接收信号所在子帧中的至少一个OFDM符号的定时位置及该定时位置之前的预定偏移量处获取信号，并利用获取的信号进行第一次频偏估计，预定偏移量的长度小于接收信号的循环前缀长度；
第二频偏估计模块202，用于对接收信号进行导频信道估计，并根据导频信道估计结 果进行第二次频偏估计，通过第二次频偏估计对第一次频偏估计的结果进行补偿。
由于OFDM符号的定时位置及之前的预定偏移量的时域间隔远远小于两个时隙的导频符号的时域间隔，因此，第一次频偏估计能够获得较大的频偏范围，然后通过两个时隙的导频符号的导频信道估计进行第二次频偏估计，以便对第一次频偏估计的结果进行补偿。本发明实施例提供的技术方案，可估计的频偏范围扩大，准确性较好，适用于高速及高铁场景。
较佳地，第一频偏估计模块201用于：
从上述子帧中的至少一个OFDM符号的定时位置及该定时位置之前的预定偏移量处获取频域接收信号；
确定上述OFDM符号的定时位置及该定时位置之前的预定偏移量处的频域接收信号的相位差；
根据该相位差进行第一次频偏估计。
较佳地，第一频偏估计模块201用于：
从上述子帧中的至少一个OFDM符号的定时位置及该定时位置之前的预定偏移量处获取时域接收信号；
截取上述OFDM符号的定时位置的时域接收信号的后预定偏移量长度的时域信号，并截取该定时位置之前的预定偏移量处的时域接收信号的前预定偏移量长度的时域信号；
确定截取的时域信号之间的相位差；
根据该相位差进行第一次频偏估计。
基于上述任意装置实施例，较佳地，第二频偏估计模块202具体用于：
对上述子帧中两个时隙的导频信号进行导频信道估计；
使用第一次频偏估计的结果对其中一个时隙的导频信号的导频信道估计结果进行补偿；
根据一个时隙的导频信号的导频信道估计结果和另一个时隙的导频信号的补偿后的导频信道估计结果进行第二次频偏估计；
将第一次频偏估计结果与第二次频偏估计结果之和，作为最终的频偏估计结果。
较佳地，第二频偏估计模块202具体用于：
对上述子帧中两个时隙的导频信号进行导频信道估计；
根据导频信道估计结果确定两个时隙的导频信号的相位差；
根据第一次频偏估计的结果确定两个时隙的导频信号的相位差的取值范围；
根据确定了取值范围的相位差进行第二次频偏估计，将第二次频偏估计结果作为最终的频偏估计结果。
较佳地，第二频偏估计模块202具体用于：
对所述子帧中两个时隙的导频信号进行导频信道估计；
使用第一次频偏估计的结果对其中一个时隙的导频信号的导频信道估计结果进行补偿；
根据一个时隙的导频信号的导频信道估计结果和另一个时隙的导频信号的补偿后的导频信道估计结果通过插值方法进行频偏补偿。
基于与方法同样的发明构思，本发明实施例提供另一种频偏估计和补偿的装置，如图3所示，包括：
处理器301，该处理器301被配置为执行具有下列功能的计算机程序：从接收信号所在子帧中的至少一个OFDM符号的定时位置及该定时位置之前的预定偏移量处获取信号，并利用获取的信号进行第一次频偏估计，预定偏移量的长度小于接收信号的循环前缀长度；对接收信号进行导频信道估计，并根据导频信道估计结果进行第二次频偏估计，通过第二次频偏估计对第一次频偏估计的结果进行补偿；
存储器302，该存储器302被配置为保存上述计算机程序的代码。
由于OFDM符号的定时位置及之前的预定偏移量的时域间隔远远小于两个时隙的导频符号的时域间隔，因此，第一次频偏估计能够获得较大的频偏范围，然后通过两个时隙的导频符号的导频信道估计进行第二次频偏估计，以便对第一次频偏估计的结果进行补偿。本发明实施例提供的技术方案，可估计的频偏范围扩大，准确性较好，适用于高速及高铁场景。
本领域内的技术人员应明白，本发明的实施例可提供为方法、***、或计算机程序产品。因此，本发明可采用完全硬件实施例、完全软件实施例、或结合软件和硬件方面的实施例的形式。而且，本发明可采用在一个或多个其中包含有计算机可用程序代码的计算机可用存储介质(包括但不限于磁盘存储器、CD-ROM、光学存储器等)上实施的计算机程序产品的形式。
本发明是参照根据本发明实施例的方法、设备(***)、和计算机程序产品的流程图和/或方框图来描述的。应理解可由计算机程序指令实现流程图和/或方框图中的每一流程和/或方框、以及流程图和/或方框图中的流程和/或方框的结合。可提供这些计算机程序指令到通用计算机、专用计算机、嵌入式处理机或其他可编程数据处理设备的处理器以产生一个机器，使得通过计算机或其他可编程数据处理设备的处理器执行的指令产生用于实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能的装置。
这些计算机程序指令也可存储在能引导计算机或其他可编程数据处理设备以特定方 式工作的计算机可读存储器中，使得存储在该计算机可读存储器中的指令产生包括指令装置的制造品，该指令装置实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能。
这些计算机程序指令也可装载到计算机或其他可编程数据处理设备上，使得在计算机或其他可编程设备上执行一系列操作步骤以产生计算机实现的处理，从而在计算机或其他可编程设备上执行的指令提供用于实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能的步骤。
尽管已描述了本发明的优选实施例，但本领域内的技术人员一旦得知了基本创造性概念，则可对这些实施例作出另外的变更和修改。所以，所附权利要求意欲解释为包括优选实施例以及落入本发明范围的所有变更和修改。
显然，本领域的技术人员可以对本发明实施例进行各种改动和变型而不脱离本发明实施例的精神和范围。这样，倘若本发明实施例的这些修改和变型属于本发明权利要求及其等同技术的范围之内，则本发明也意图包含这些改动和变型在内。

Claims (12)

  1. 一种频偏估计和补偿的方法，其特征在于，包括：
    从接收信号所在子帧中的至少一个正交频分复用OFDM符号的定时位置及所述定时位置之前的预定偏移量处获取信号，并利用获取的信号进行第一次频偏估计，所述预定偏移量的长度不大于所述接收信号的循环前缀长度；
    对所述接收信号进行导频信道估计，并根据导频信道估计结果进行第二次频偏估计，通过第二次频偏估计对第一次频偏估计的结果进行补偿。
  2. 根据权利要求1所述的方法，其特征在于，从接收信号所在子帧中的至少一个OFDM符号的定时位置及所述定时位置之前的预定偏移量处获取信号，并利用获取的信号进行第一次频偏估计，包括：
    从所述子帧中的至少一个导频信号所在的OFDM符号的定时位置及所述定时位置之前的预定偏移量处获取频域接收信号；
    确定所述OFDM符号的定时位置及所述定时位置之前的预定偏移量处的频域接收信号的相位差；
    根据所述相位差进行第一次频偏估计。
  3. 根据权利要求1所述的方法，其特征在于，从接收信号所在子帧中的至少一个OFDM符号的定时位置及所述定时位置之前的预定偏移量处获取信号，并利用获取的信号进行第一次频偏估计，包括：
    从所述子帧中的至少一个OFDM符号的定时位置及所述定时位置之前的预定偏移量处获取时域接收信号；
    截取所述OFDM符号的定时位置的时域接收信号的后所述预定偏移量长度的时域信号，并截取所述定时位置之前的预定偏移量处的时域接收信号的前所述预定偏移量长度的时域信号；
    确定截取的时域信号之间的相位差；
    根据所述相位差进行第一次频偏估计。
  4. 根据权利要求1-3任一项所述的方法，其特征在于，对所述接收信号进行导频信道估计，并根据导频信道估计结果进行第二次频偏估计，通过第二次频偏估计对第一次频偏估计的结果进行补偿，包括：
    对所述子帧中两个时隙的导频信号进行导频信道估计；
    使用第一次频偏估计的结果对其中一个时隙的导频信号的导频信道估计结果进行补 偿；
    根据一个时隙的导频信号的导频信道估计结果和另一个时隙的导频信号的补偿后的导频信道估计结果进行第二次频偏估计；
    将所述第一次频偏估计结果与第二次频偏估计结果之和，作为最终的频偏估计结果。
  5. 根据权利要求1-3任一项所述的方法，其特征在于，对所述接收信号进行导频信道估计，并根据导频信道估计结果进行第二次频偏估计，通过第二次频偏估计对第一次频偏估计的结果进行补偿，包括：
    对所述子帧中两个时隙的导频信号进行导频信道估计；
    根据导频信道估计结果确定两个时隙的导频信号的相位差；
    根据第一次频偏估计的结果确定所述两个时隙的导频信号的相位差的取值范围；
    根据确定了取值范围的所述相位差进行第二次频偏估计，将第二次频偏估计结果作为最终的频偏估计结果。
  6. 根据权利要求1-3任一项所述的方法，其特征在于，对所述接收信号进行导频信道估计，并根据导频信道估计结果进行第二次频偏估计，通过第二次频偏估计对第一次频偏估计的结果进行补偿，包括：
    对所述子帧中两个时隙的导频信号进行导频信道估计；
    使用第一次频偏估计的结果对其中一个时隙的导频信号的导频信道估计结果进行补偿；
    根据一个时隙的导频信号的导频信道估计结果和另一个时隙的导频信号的补偿后的导频信道估计结果通过插值方法进行频偏补偿。
  7. 一种频偏估计和补偿的装置，其特征在于，包括：
    第一频偏估计模块，用于从接收信号所在子帧中的至少一个正交频分复用OFDM符号的定时位置及所述定时位置之前的预定偏移量处获取信号，并利用获取的信号进行第一次频偏估计，所述预定偏移量的长度不大于所述接收信号的循环前缀长度；
    第二频偏估计模块，用于对所述接收信号进行导频信道估计，并根据导频信道估计结果进行第二次频偏估计，通过第二次频偏估计对第一次频偏估计的结果进行补偿。
  8. 根据权利要求7所述的装置，其特征在于，第一频偏估计模块用于：
    从所述子帧中的至少一个导频信号所在的OFDM符号的定时位置及所述定时位置之前的预定偏移量处获取频域接收信号；
    确定所述OFDM符号的定时位置及所述定时位置之前的预定偏移量处的频域接收信号的相位差；
    根据所述相位差进行第一次频偏估计。
  9. 根据权利要求7所述的装置，其特征在于，第一频偏估计模块用于：
    从所述子帧中的至少一个OFDM符号的定时位置及所述定时位置之前的预定偏移量处获取时域接收信号；
    截取所述OFDM符号的定时位置的时域接收信号的后所述预定偏移量长度的时域信号，并截取所述定时位置之前的预定偏移量处的时域接收信号的前所述预定偏移量长度的时域信号；
    确定截取的时域信号之间的相位差；
    根据所述相位差进行第一次频偏估计。
  10. 根据权利要求7-9任一项所述的装置，其特征在于，第二频偏估计模块用于：
    对所述接收信号在两个时隙的导频信号进行导频信道估计；
    使用第一次频偏估计的结果对其中一个时隙的导频信号的导频信道估计结果进行补偿；
    根据一个时隙的导频信号的导频信道估计结果和另一个时隙的导频信号的补偿后的导频信道估计结果进行第二次频偏估计；
    将所述第一次频偏估计结果与第二次频偏估计结果之和，作为最终的频偏估计结果。
  11. 根据权利要求7-9任一项所述的装置，其特征在于，第二频偏估计模块用于：
    对所述接收信号在两个时隙的导频信号进行导频信道估计；
    根据导频信道估计结果确定两个时隙的导频信号的相位差；
    根据第一次频偏估计的结果确定所述两个时隙的导频信号的相位差的取值范围；
    根据确定了取值范围的所述相位差进行第二次频偏估计，将第二次频偏估计结果作为最终的频偏估计结果。
  12. 根据权利要求7-9任一项所述的装置，其特征在于，所述第二频偏估计模块用于：
    对所述子帧中两个时隙的导频信号进行导频信道估计；
    使用第一次频偏估计的结果对其中一个时隙的导频信号的导频信道估计结果进行补偿；
    根据一个时隙的导频信号的导频信道估计结果和另一个时隙的导频信号的补偿后的导频信道估计结果通过插值方法进行频偏补偿。
PCT/CN2015/074292 2014-03-21 2015-03-16 一种频偏估计和补偿的方法及装置 WO2015139590A1 (zh)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN201410109805.XA CN103873396B (zh) 2014-03-21 2014-03-21 一种频偏估计和补偿的方法及装置
CN201410109805.X 2014-03-21

Publications (1)

Publication Number Publication Date
WO2015139590A1 true WO2015139590A1 (zh) 2015-09-24

Family

ID=50911533

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2015/074292 WO2015139590A1 (zh) 2014-03-21 2015-03-16 一种频偏估计和补偿的方法及装置

Country Status (2)

Country Link
CN (1) CN103873396B (zh)
WO (1) WO2015139590A1 (zh)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113055995A (zh) * 2019-12-26 2021-06-29 中兴通讯股份有限公司 频偏估计方法和装置
CN115134201A (zh) * 2022-07-12 2022-09-30 上海应用技术大学 一种对时延扩展迭代计算优化v2x信道估计的方法
CN115333911A (zh) * 2022-08-15 2022-11-11 四川创智联恒科技有限公司 一种ofdm***中基于导频的频偏估计方法
CN115484134A (zh) * 2022-09-01 2022-12-16 成都中科微信息技术研究院有限公司 一种适用于大多径时延扩展的ofdm***信道估计方法、介质及装置

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103873396B (zh) * 2014-03-21 2018-03-23 电信科学技术研究院 一种频偏估计和补偿的方法及装置
CN105991484B (zh) * 2015-01-30 2020-04-03 中兴通讯股份有限公司 一种频偏估计的方法和装置
CN105680924B (zh) * 2016-01-28 2019-04-16 西南交通大学 超高移动条件下基于频域差分相位的mimo-ofdm***频偏估计方法
CN109274619B (zh) * 2017-07-18 2020-10-20 电信科学技术研究院 一种频率偏移确定方法及装置
CN110392003B (zh) * 2018-04-17 2020-12-04 大唐移动通信设备有限公司 一种信号接收方法及装置
CN110740106B (zh) * 2018-07-19 2021-07-20 大唐移动通信设备有限公司 一种频偏估计方法及装置
CN110602015B (zh) * 2019-09-12 2020-07-03 北京邮电大学 一种ofdm***中多普勒频偏补偿、信号发送方法及装置
CN112714086B (zh) * 2019-10-25 2022-04-05 大唐移动通信设备有限公司 一种频偏估计方法及基站
CN112688891B (zh) * 2020-12-30 2023-09-01 中电科思仪科技(安徽)有限公司 一种5g毫米波上行信号相位噪声估计与补偿装置及方法

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101604990A (zh) * 2008-06-13 2009-12-16 大唐移动通信设备有限公司 频偏补偿方法和装置
US20100008216A1 (en) * 2006-08-30 2010-01-14 Posdata Co., Ltd. Apparatus and method for estimating and compensating time offset and/or carrier frequency offset in mimo system based ofdm/ofdma
CN101808060A (zh) * 2010-03-17 2010-08-18 北京天碁科技有限公司 频偏处理方法和装置
CN102137049A (zh) * 2010-01-25 2011-07-27 中兴通讯股份有限公司 一种lte***中的单时隙频偏估计方法和装置
CN103873396A (zh) * 2014-03-21 2014-06-18 电信科学技术研究院 一种频偏估计和补偿的方法及装置

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102137048B (zh) * 2010-01-22 2015-11-25 中兴通讯股份有限公司 一种频偏估计的方法及***

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100008216A1 (en) * 2006-08-30 2010-01-14 Posdata Co., Ltd. Apparatus and method for estimating and compensating time offset and/or carrier frequency offset in mimo system based ofdm/ofdma
CN101604990A (zh) * 2008-06-13 2009-12-16 大唐移动通信设备有限公司 频偏补偿方法和装置
CN102137049A (zh) * 2010-01-25 2011-07-27 中兴通讯股份有限公司 一种lte***中的单时隙频偏估计方法和装置
CN101808060A (zh) * 2010-03-17 2010-08-18 北京天碁科技有限公司 频偏处理方法和装置
CN103873396A (zh) * 2014-03-21 2014-06-18 电信科学技术研究院 一种频偏估计和补偿的方法及装置

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113055995A (zh) * 2019-12-26 2021-06-29 中兴通讯股份有限公司 频偏估计方法和装置
CN113055995B (zh) * 2019-12-26 2023-10-27 中兴通讯股份有限公司 频偏估计方法和装置
CN115134201A (zh) * 2022-07-12 2022-09-30 上海应用技术大学 一种对时延扩展迭代计算优化v2x信道估计的方法
CN115333911A (zh) * 2022-08-15 2022-11-11 四川创智联恒科技有限公司 一种ofdm***中基于导频的频偏估计方法
CN115333911B (zh) * 2022-08-15 2023-04-07 四川创智联恒科技有限公司 一种ofdm***中基于导频的频偏估计方法
CN115484134A (zh) * 2022-09-01 2022-12-16 成都中科微信息技术研究院有限公司 一种适用于大多径时延扩展的ofdm***信道估计方法、介质及装置

Also Published As

Publication number Publication date
CN103873396B (zh) 2018-03-23
CN103873396A (zh) 2014-06-18

Similar Documents

Publication Publication Date Title
WO2015139590A1 (zh) 一种频偏估计和补偿的方法及装置
JP5613233B2 (ja) 直交周波数分割多重化システムの時間オフセット推定装置及び方法
US11095491B2 (en) Methods and apparatus for frequency offset estimation
US9807718B2 (en) Secondary cell synchronization for carrier aggregation
US7929624B2 (en) Cell ID detection in cellular communication systems
US8744013B2 (en) Channel estimation for OFDM systems
US7907673B2 (en) Robust and low-complexity combined signal power estimation
JP2011507323A (ja) Ｏｆｄｍ受信機におけるｆｆｔウインドウの位置決め方法および装置
KR101505091B1 (ko) 직교주파수분할 방식 기반의 무선통신 시스템에서 초기 동기화를 위한 장치 및 방법
AU2017219686B2 (en) NB-loT receiver operating at minimum sampling rate
Huang et al. Joint time and frequency offset estimation in LTE downlink
KR20140112905A (ko) 장치 간 직접 통신을 지원하는 무선 통신 시스템에서 주파수 동기를 위한 방법 및 장치
CN103269322A (zh) 一种确定频偏值的方法和装置
JPWO2008096408A1 (ja) 無線端末装置
WO2017181352A1 (en) Timing offset estimation in an ofdm-based system by sinr measurement
JP2000341236A (ja) Ｏｆｄｍ信号受信装置、ｏｆｄｍ信号通信システム及びその通信制御方法
CN101529840B (zh) 针对ofdm的鲁棒且低复杂度合并信号功率估计
KR100884381B1 (ko) 주파수 옵셋 추정 장치 및 방법
US9860861B2 (en) Timing offset estimation in an OFDM-based system by SINR measurement
JP2004254295A (ja) 直交波周波数分割多重システムの搬送波周波数オフセットと位相の補償装置及び方法
CN115396070B (zh) 信号同步方法、装置及存储介质
KR100982780B1 (ko) Ｏｆｄｍ 기반 ｗｌａｎ 시스템에서 반송파 주파수 오프셋 추정 방법
JP2004112847A (ja) Ｏｆｄｍ信号通信システム
KR20150086591A (ko) 무선 네트워크에서 시간 동기화 방법 및 장치
KR20240030754A (ko) User equipment에서 RFO 추정 및 동기화 신호 검출 방법

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 15765066

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 15765066

Country of ref document: EP

Kind code of ref document: A1