WO2016074165A1 - Method and device for reducing inter-subcarrier interference in ofdma system - Google Patents

Method and device for reducing inter-subcarrier interference in ofdma system Download PDF

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Publication number
WO2016074165A1
WO2016074165A1 PCT/CN2014/090876 CN2014090876W WO2016074165A1 WO 2016074165 A1 WO2016074165 A1 WO 2016074165A1 CN 2014090876 W CN2014090876 W CN 2014090876W WO 2016074165 A1 WO2016074165 A1 WO 2016074165A1
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user equipment
carrier frequency
offset value
frequency offset
pilot information
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PCT/CN2014/090876
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French (fr)
Chinese (zh)
Inventor
薛鑫
颜敏
王宁娟
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华为技术有限公司
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Priority to PCT/CN2014/090876 priority Critical patent/WO2016074165A1/en
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    • 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
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J1/00—Frequency-division multiplex systems
    • H04J1/02—Details
    • H04J1/16—Monitoring arrangements

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  • the embodiments of the present invention relate to communication technologies, and in particular, to a method and apparatus for reducing inter-subcarrier interference in an Orthogonal Frequency Division Multiple Access (OFDMA) system.
  • OFDMA Orthogonal Frequency Division Multiple Access
  • the OFDMA system divides the transmission bandwidth into orthogonal sets of subcarriers that do not overlap each other, and allocates different subcarrier sets to different users to implement multiple access.
  • the data S k is passed through a formula.
  • IDFT Inverse Discrete Fourier Transform
  • DFT Discrete Fourier Transform
  • each user sends a signal carrying a different carrier frequency offset, resulting in data obtained by the receiving end when performing DFT conversion on the received signal.
  • p represents different users
  • Embodiments of the present invention provide a method and apparatus for reducing inter-subcarrier interference in an OFDMA system, which are used to reduce inter-subcarrier interference in an OFDMA system.
  • An embodiment of the present invention provides a method for reducing inter-subcarrier interference in an OFDMA system, including:
  • An embodiment of the present invention provides an apparatus for reducing inter-subcarrier interference in an OFDMA system, where the apparatus is an access node AP or a base station, and includes:
  • An estimation module configured to estimate a carrier frequency offset value of the user equipment according to a pilot symbol in a subcarrier occupied by the user equipment;
  • a determining module configured to determine, according to the carrier frequency offset value, an inter-carrier interference ICI cancellation filter coefficient corresponding to the user equipment;
  • a filtering module configured to perform filtering processing on the frequency domain data of the user equipment by using the ICI to eliminate filter coefficients.
  • An embodiment of the present invention provides a method and apparatus for reducing inter-subcarrier interference in an OFDMA system, by estimating a carrier frequency offset value of the user equipment according to a pilot symbol in a subcarrier occupied by a user equipment; Determining an inter-carrier interference ICI cancellation filter coefficient corresponding to the user equipment, and performing filter processing on the frequency domain data of the user equipment by using the ICI cancellation filter coefficient; eliminating the user Interference between subcarriers occupied by the device, thereby reducing interference between subcarriers in the OFDMA system.
  • FIG. 1 is a schematic diagram of an application scenario of a method for reducing inter-subcarrier interference in an OFDMA system according to the present invention
  • Embodiment 2 is a flowchart of Embodiment 1 of a method for reducing inter-subcarrier interference in an OFDMA system according to the present invention
  • Embodiment 3 is a flowchart of Embodiment 2 of a method for reducing inter-subcarrier interference in an OFDMA system according to the present invention
  • FIG. 4 is a schematic diagram 1 of a WLAN network frame data structure according to the present invention.
  • FIG. 5 is a schematic diagram 2 of a WLAN network frame data structure according to the present invention.
  • Embodiment 6 is a flowchart of Embodiment 3 of a method for reducing inter-subcarrier interference in an OFDMA system according to the present invention
  • FIG. 7 is a schematic structural diagram of Embodiment 1 of an apparatus for reducing inter-subcarrier interference in an OFDMA system according to the present invention.
  • FIG. 8 is a schematic structural diagram of Embodiment 4 of an apparatus for reducing inter-subcarrier interference in an OFDMA system according to the present invention.
  • FIG. 1 is a schematic diagram of an application scenario of a method for reducing inter-subcarrier interference in an OFDMA system according to the present invention.
  • each user equipment 12 occupies different subcarriers.
  • the data is transmitted to the access node (AP, Access Point) 11 by means of OFDMA; the access node 11 simultaneously receives data transmitted by the plurality of user equipments 12.
  • AP Access Point
  • the method for reducing inter-subcarrier interference in the OFDMA system of the present invention is applicable.
  • the scenario may also be a Long Term Evolution (LTE) network.
  • LTE Long Term Evolution
  • Each user equipment in the LTE network sends data to the base station by means of OFDMA.
  • Embodiment 1 is a flowchart of Embodiment 1 of a method for reducing inter-subcarrier interference in an OFDMA system according to the present invention. As shown in FIG. 2, the method in this embodiment may include:
  • Step 201 Estimating a carrier frequency offset value of the user equipment according to a pilot symbol in a subcarrier occupied by the user equipment;
  • Step 202 Determine, according to the carrier frequency offset value, an inter-carrier interference ICI cancellation filter coefficient corresponding to the user equipment.
  • Step 203 Perform filter processing on the frequency domain data of the user equipment by using the ICI cancellation filter coefficient.
  • the carrier frequency used when the user equipment is up-converted and the access node or the base station are down-converted.
  • the carrier frequency offset destroys the orthogonality between the subcarriers, resulting in mutual interference between the subcarriers.
  • the access node or the base station estimates the carrier frequency offset value of the user equipment according to the pilot symbol in the subcarrier occupied by the user equipment; and determines, according to the carrier frequency offset value, the user equipment corresponding Inter-carrier interference ICI cancellation filter coefficients; filtering the frequency domain data of the user equipment by filtering the filter coefficients by the ICI.
  • the inter-carrier interference of the subcarriers occupied by a user equipment is divided into two parts, one part is the interference between the subcarriers occupied by the user equipment, and the other part is the subcarrier occupied by other user equipments to the user.
  • the interference of the subcarriers occupied by the device is divided into two parts, one part is the interference between the subcarriers occupied by the user equipment, and the other part is the subcarrier occupied by other user equipments to the user.
  • the invention determines by experiments that the interference between the subcarriers occupied by the user equipment is the main reason that the access node or the base station cannot correctly demodulate the data on the subcarriers occupied by the user equipment; therefore, the present invention passes
  • the access node or the base station estimates the carrier frequency offset value of the user equipment according to the pilot symbol in the subcarrier occupied by the user equipment, and determines the inter-carrier interference corresponding to the user equipment according to the carrier frequency offset value. Eliminating the filter coefficients by the ICI; filtering the frequency domain data of the user equipment by using the ICI cancellation filter coefficients; eliminating interference between subcarriers occupied by the user equipment, thereby reducing the OFDMA system Inter-subcarrier interference.
  • Embodiment 3 is a flowchart of Embodiment 2 of a method for reducing inter-subcarrier interference in an OFDMA system according to the present invention. As shown in FIG. 3, the method in this embodiment may include:
  • Step 301 Estimate a carrier frequency offset value of the user equipment according to a pilot symbol in a subcarrier occupied by the user equipment.
  • At least two sets of pilot information are obtained from the training sequence or the data symbol; and according to the pilot information, the carrier frequency offset value CFO(est) is obtained by using the following formula (1):
  • pilot 1, n is the first set of pilot information
  • pilot 2, n is the second set of pilot information
  • TimeDist is the time interval between the two sets of pilot information
  • n is a positive integer.
  • the conj function is used to find the conjugate of the complex number
  • the arg function is used to find the argument angle of the complex number
  • acquiring at least two sets of pilot information from the training sequence or the data symbol includes: acquiring a set of pilot information from the first training sequence and the second training sequence respectively; or acquiring one from the first training sequence.
  • the group of pilot information acquires another set of pilot information from the first data symbol; or, the two sets of pilot information are respectively obtained from the first data symbol and the second data symbol.
  • the two sets of pilot information acquired in the present invention are in the same subcarrier.
  • a set of pilot information may be separately obtained from any two training sequences.
  • the first set of pilot information of the time position is used as the first group of pilot information
  • the set of pilot information of the later time position is used as the second group of pilot information.
  • FIG. 4 is a schematic diagram 1 of a WLAN network frame data structure according to the present invention. As shown in FIG. 4, there are two or more training sequences in the frame data, and the first group guide can be obtained from a long training field (LTF) 1 Frequency information, obtaining a second set of pilot information from LTF2.
  • LTF long training field
  • the first set of pilot information acquired from the LTF1 is carried.
  • the group pilot information may also be information carried on subcarriers with carrier positions of 7, 21, 34, 48 respectively: pilot 2,1 , pilot 2,2 , pilot 2,3 , pilot 2,4 .
  • pilot information may also be obtained only from the data symbols; or, one set of pilot information is obtained from the training sequence, and another group is obtained from the data symbols. Pilot information.
  • a set of pilot information may be separately obtained from the training sequence and any one of the data symbols.
  • FIG. 5 is a schematic diagram 2 of a WLAN network frame data structure according to the present invention. As shown in FIG. 5, there is a training sequence in the frame data, and the first group of pilot information may be obtained from the LTF1, and the second group guide is obtained from the data symbol DATA1. Frequency information.
  • the first set of pilot information acquired from the LTF1 is carried.
  • the information carried on the subcarriers with carrier positions of 7, 21, 34, 48 respectively: pilot 1,1 , pilot 1,2 , pilot 1,3 , pilot 1,4 ; the second obtained from DATA1
  • the group pilot information may also be information carried on subcarriers with carrier positions of 7, 21, 34, 48 respectively: pilot 2,1 , pilot 2,2 , pilot 2,3 , pilot 2,4 .
  • the carrier position of the two sets of pilot information for the same user equipment should also be the same .
  • a set of pilot information may be obtained from any two data symbols, and the group of time positions is forwarded.
  • the pilot information is used as the first group of pilot information, and the set of pilot information at the time position is used as the second group of pilot information.
  • a first set of pilot information can be obtained from DATA1 and a second set of pilot information can be obtained from DATA2.
  • each subcarrier occupied by the same user equipment For each subcarrier occupied by the same user equipment, the carrier frequency domain used in the up-conversion of the user equipment and the carrier used in the down-conversion of the receiving end caused by the mismatch between the user equipment and the oscillator of the receiving end
  • the offsets between the frequencies are the same, that is, each subcarrier occupied by the same user equipment has the same carrier frequency offset. Therefore, in the present invention, only the two sets of pilot information on any subcarrier occupied by the user equipment are acquired, and the carrier frequency offset of all subcarriers of the user equipment can be acquired.
  • Step 302 Calculate an ICI cancellation filter coefficient corresponding to the user equipment according to the carrier frequency offset value and the number of FFT points used by the user equipment to perform FFT transformation;
  • N tap is the filter tap coefficient
  • ⁇ 2 ⁇ CFO(est)
  • CFO(est) is the carrier frequency offset value
  • the ICI cancellation filter coefficient W FilterTap can be obtained as:
  • W FilterTap ⁇ -0.0005+0.0001i -0.0005+0.0001i -0.0006+0.0001i-0.0007+0.0001i -0.0008+0.0001i -0.0009+0.0001i-0.0012+0.0001i-0.0016+0.0001i -0.0024+0.0001i - 0.0047+0.0001i 1.00000.0047+0.0001i 0.0023+0.0001i 0.0016+0.0001i 0.0012+0.0001i0.0009+0.0001i 0.0008+0.0001i 0.0007+0.0001i 0.0006+0.0001i0.0005+0.0001i 0.0005+0.0001i ⁇
  • Step 303 Perform filter processing on the frequency domain data of the user equipment by using the ICI cancellation filter coefficient.
  • the obtained ICI cancellation filter coefficient is convoluted with the received frequency domain data of the user equipment.
  • the selected ICI cancellation filter coefficients are ⁇ w -10 , w -9 ,...,w 0 , ...w 10 ⁇
  • the data after convolution of the frequency domain data of the user equipment is ⁇ x 1 , x 2 , x 3 , ... x N ⁇ ;
  • the present invention estimates a carrier frequency offset value of the user equipment according to a pilot symbol in a subcarrier occupied by the user equipment; and uses an FFT used according to the carrier frequency offset value and the user equipment to perform FFT transformation.
  • Counting calculating an ICI cancellation filter coefficient corresponding to the user equipment; performing filter processing on the frequency domain data of the user equipment by using the ICI cancellation filter coefficient; eliminating between subcarriers occupied by the user equipment Interference, thereby reducing inter-subcarrier interference in an OFDMA system.
  • the problem that the receiving end cannot correctly demodulate data from each subcarrier is solved.
  • FIG. 6 is a flowchart of Embodiment 3 of a method for reducing inter-subcarrier interference in an OFDMA system according to the present invention. As shown in FIG. 6, the method in this embodiment may include:
  • Step 601 Estimate a carrier frequency offset value of the user equipment according to a pilot symbol in a subcarrier occupied by the user equipment.
  • step 601 is the same as step 301, and details are not described herein again.
  • Step 602 Select, according to the carrier frequency offset value and the number of FFT points used by the user equipment to perform FFT transformation, the ICI cancellation filter coefficient corresponding to the user equipment from the pre-stored ICI cancellation filter coefficients;
  • the FFT point matching, the filter tap coefficient matching, and the carrier frequency offset are used according to the carrier frequency offset value, the FFT point used by the user equipment for performing FFT transformation, and a preset filter tap coefficient.
  • the value distance closest principle selects the ICI cancellation filter coefficient corresponding to the user equipment from the pre-stored ICI cancellation filter coefficients.
  • the estimated CFO(est) is 367.3KHz
  • the number of FFT points is 256.
  • ICI-Filter ⁇ -0.0005+0.0001i -0.0006+0.0001i -0.0006+0.0001i-0.0007+0.0001i -0.0009+0.0001i -0.0010+0.0001i -0.0013+0.0001i-0.0017+0.0001i -0.0026+0.0001i -0.0051+0.0001i 1.00000.0051+0.0001i 0.0026+0.0001i 0.0017+0.0001i 0.0013+0.0001i0.0010+0.0001i 0.0009+0.0001i 0.0007+0.0001i 0.0006+0.0001i0.0006+0.0001i 0.0005+0.0001i ⁇
  • the estimated CFO(est) -367.3KHz
  • the FFT point number is 256
  • ICI-Filter ⁇ 0.0005-0.0001i 0.0006-0.0001i 0.0006-0.0001i0.0007-0.0001i 0.0009-0.0001i 0.0010-0.0001i 0.0013-0.0001i0.0017-0.0001i 0.0026-0.0001i 0.0051-0.0001i 1.0000-0.0051 -0.0001i -0.0026-0.0001i -0.0017-0.0001i -0.0013-0.0001i-0.0010-0.0001i -0.0009-0.0001i -0.0007-0.0001i -0.0006-0.0001i-0.0006-0.0001i -0.0005-0.0001i ⁇
  • Step 603 Perform filter processing on the frequency domain data of the user equipment by using the ICI cancellation filter coefficient.
  • step 603 is the same as step 303, and details are not described herein again.
  • the present invention estimates a carrier frequency offset value of the user equipment according to a pilot symbol in a subcarrier occupied by the user equipment; and uses an FFT used by the user equipment to perform FFT transformation according to the carrier frequency offset value. a point and a preset filter tap coefficient, selecting an ICI cancellation filter coefficient corresponding to the user equipment from pre-stored ICI cancellation filter coefficients; removing a filter coefficient by the ICI, and frequency domain of the user equipment.
  • the data is subjected to filtering processing; interference between subcarriers occupied by the user equipment is eliminated, thereby reducing inter-subcarrier interference in the OFDMA system.
  • the problem that the receiving end cannot correctly demodulate data from each subcarrier is solved.
  • FIG. 7 is a schematic structural diagram of Embodiment 1 of an apparatus for reducing inter-subcarrier interference in an OFDMA system according to the present invention.
  • the apparatus may be an access node in a WLAN network or a base station in an LTE network, as shown in FIG.
  • the apparatus may include an estimation module 701, a determination module 702, and a filtering module 703.
  • the estimating module 701 is configured to estimate a carrier frequency offset value of the user equipment according to a pilot symbol in a subcarrier occupied by the user equipment, where the determining module 702 is configured to determine, according to the carrier frequency offset value, The inter-carrier interference ICI cancellation filter coefficient corresponding to the user equipment; the filtering module 703 is configured to filter the frequency domain data of the user equipment by using the ICI cancellation filter coefficient.
  • the device in this embodiment may be used to implement the technical solution of the method embodiment shown in FIG. 2, and the implementation principle and technical effects are similar, and details are not described herein again.
  • the estimating module 701 is specifically configured to:
  • the carrier frequency offset value CFO(est) is obtained by using the following formula (1):
  • pilot 1, n is the first set of pilot information
  • pilot 2, n is the second set of pilot information
  • TimeDist is the time interval between the two sets of pilot information
  • n is a positive integer.
  • the estimating module 701 is specifically configured to: obtain a set of pilot information from the first training sequence and the second training sequence respectively; or obtain a set of pilot information from the first training sequence, from the first Another set of pilot information is acquired in the data symbol; or two sets of pilot information are respectively obtained from the first data symbol and the second data symbol.
  • the determining module 702 is configured to calculate an ICI cancellation filter coefficient corresponding to the user equipment according to the carrier frequency offset value and an FFT point used by the user equipment to perform FFT transformation.
  • the determining module 702 is specifically configured to:
  • N tap is the filter tap coefficient
  • ⁇ 2 ⁇ CFO(est)
  • CFO(est) is the carrier frequency offset value
  • the device in this embodiment may be used to implement the technical solution of the method embodiment shown in FIG. 3, and the implementation principle and technical effects are similar, and details are not described herein again.
  • the estimating module 701 is specifically configured to:
  • the carrier frequency offset value CFO(est) is obtained by using the following formula (1):
  • pilot 1, n is the first set of pilot information
  • pilot 2, n is the second set of pilot information
  • TimeDist is the time interval between the two sets of pilot information
  • n is a positive integer.
  • the estimating module 701 is specifically configured to: obtain a set of pilot information from the first training sequence and the second training sequence respectively; or obtain a set of pilot information from the first training sequence, from the first Another set of pilot information is acquired in the data symbol; or two sets of pilot information are respectively obtained from the first data symbol and the second data symbol.
  • the determining module 702 is specifically configured to:
  • the determining module 702 is specifically configured to: perform FFT point matching and filtering according to the carrier frequency offset value, the FFT point used by the user equipment for performing FFT transformation, and a preset filter tap coefficient.
  • the tap coefficient matching and the carrier frequency offset value are closest to the principle, and the ICI cancellation filter coefficient corresponding to the user equipment is selected from the pre-stored ICI cancellation filter coefficients.
  • the device in this embodiment may be used to implement the technical solution of the method embodiment shown in FIG. 6.
  • the implementation principle and technical effects are similar, and details are not described herein again.
  • FIG. 8 is a schematic structural diagram of Embodiment 4 of an apparatus for reducing inter-subcarrier interference in an OFDMA system according to the present invention.
  • the apparatus may be an access node in a WLAN network or a base station in an LTE network, as shown in FIG.
  • the apparatus can include a processor 801 and a memory 802.
  • the apparatus can also include a transmitter 803 and a receiver 804. Transmitter 803 and receiver 804 can be coupled to processor 801.
  • the transmitter 803 is configured to transmit data or information
  • the receiver 804 is configured to receive data or information
  • the memory 802 stores execution instructions, when the device is in operation
  • the processor 801 communicates with the memory 802, and the processor 801 calls the memory 802. Execution instructions for performing the following operations:
  • the estimating a carrier frequency offset value of the user equipment according to the pilot symbol in the subcarrier occupied by the user equipment including:
  • the carrier frequency offset value CFO(est) is obtained by using the following formula (1):
  • pilot 1, n is the first set of pilot information
  • pilot 2, n is the second set of pilot information
  • TimeDist is the time interval between the two sets of pilot information
  • n is a positive integer.
  • the obtaining at least two sets of pilot information from the training sequence or the data symbol includes:
  • two sets of pilot information are respectively obtained from the first data symbol and the second data symbol.
  • the determining, according to the carrier frequency offset value, the inter-carrier interference ICI cancellation filter coefficient corresponding to the user equipment including:
  • calculating an ICI cancellation filter coefficient corresponding to the user equipment according to the carrier frequency offset value and the number of FFT points used by the user equipment to perform FFT transformation including:
  • N tap is the filter tap coefficient
  • ⁇ 2 ⁇ CFO(est)
  • CFO(est) is the carrier frequency offset value
  • the ICI cancellation filter coefficient corresponding to the user equipment is selected from the pre-stored ICI cancellation filter coefficients according to the carrier frequency offset value and the number of FFT points used by the user equipment for performing FFT transformation. include:
  • the carrier frequency offset value the number of FFT points used by the user equipment for performing FFT transformation, and the preset filter tap coefficient, the FFT point matching, the filter tap coefficient matching, and the carrier frequency offset value distance nearest principle are adopted. And selecting an ICI cancellation filter coefficient corresponding to the user equipment from the pre-stored ICI cancellation filter coefficients.
  • the base station of this embodiment may be used to perform the technical solution for reducing the inter-subcarrier interference in the OFDMA system provided by any embodiment of the present invention.
  • the implementation principle and technical effects are similar, and details are not described herein again.
  • the aforementioned program can be stored in a computer readable storage medium.
  • the program when executed, performs the steps including the foregoing method embodiments; and the foregoing storage medium includes various media that can store program codes, such as a ROM, a RAM, a magnetic disk, or an optical disk.

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Abstract

Embodiments of the present invention provide a method and device for reducing inter-subcarrier interference in an OFDMA system. The method for reducing inter-subcarrier interference in an OFDMA system comprises: estimating a carrier frequency deviation value of a user equipment according to pilot symbols in subcarriers occupied by the user equipment; determining, according to the carrier frequency deviation value, an inter-carrier interference (ICI) cancellation filter coefficient corresponding to the user equipment; and filtering frequency domain data of the user equipment by using the ICI cancellation filter coefficient. Therefore, the interference between the subcarriers occupied by the user equipment is eliminated, and the inter-subcarrier interference in the OFDMA system is reduced.

Description

OFDMA***中减小子载波间干扰的方法和装置Method and apparatus for reducing inter-subcarrier interference in an OFDMA system 技术领域Technical field
本发明实施例涉及通信技术，尤其涉及一种正交频分多址(OFDMA，Orthogonal Frequency Division Multiple Access)***中减小子载波间干扰的方法和装置。The embodiments of the present invention relate to communication technologies, and in particular, to a method and apparatus for reducing inter-subcarrier interference in an Orthogonal Frequency Division Multiple Access (OFDMA) system.
背景技术Background technique
OFDMA***将传输带宽划分成正交的互不重叠的一系列子载波集，将不同的子载波集分配给不同的用户实现多址。The OFDMA system divides the transmission bandwidth into orthogonal sets of subcarriers that do not overlap each other, and allocates different subcarrier sets to different users to implement multiple access.
现有技术中，在OFDM***的发送端，对数据Sk通过公式
Figure PCTCN2014090876-appb-000001
进行离散傅里叶逆变换(IDFT，Inverse Discrete Fourier Transform)，其中(0≤n≤N-1)；再将sn进行数模转换及上变频后发送至OFDM***的接收端；接收端对接收到的信号首先进行下变频及模数转换获得sn，对sn通过公式
Figure PCTCN2014090876-appb-000002
进行离散傅里叶变换(DFT，Discrete Fourier Transform)，其中(0≤k≤N-1)，以获得发送端发送的数据Sk。但是现有技术中，由于发送端和接收端的振荡器不匹配，导致发送端上变频时使用的载波频率与接收端下变频时使用的载波频率之间存在偏移，导致接收端对接收到的信号进行下变频及模数转换后获得的是snexp(j2πΔft)而不是sn，从而导致对snexp(j2πΔft)进行傅里叶变换时
Figure PCTCN2014090876-appb-000003
获得的Sk′与发送端发送的Sk不相等。由此可见，载波频率偏移破坏了子载波间的正交性，产生了子载波间相互干扰，造成接收端无法从各个子载波上正确地解调出数据。In the prior art, at the transmitting end of the OFDM system, the data S k is passed through a formula.
Figure PCTCN2014090876-appb-000001
Performing Inverse Discrete Fourier Transform (IDFT), where (0≤n≤N-1); then performing s n digital-to-analog conversion and up-conversion and transmitting to the receiving end of the OFDM system; The received signal is first subjected to down-conversion and analog-to-digital conversion to obtain s n , and s n is passed through the formula
Figure PCTCN2014090876-appb-000002
A Discrete Fourier Transform (DFT) is performed, in which (0 ≤ k ≤ N-1), to obtain data S k transmitted by the transmitting end. However, in the prior art, since the oscillators at the transmitting end and the receiving end do not match, there is a deviation between the carrier frequency used when the transmitting end is up-converted and the carrier frequency used when the receiving end is down-converted, so that the receiving end receives the received After the signal is down-converted and analog-to-digital converted, s n exp(j2πΔft) is obtained instead of s n , resulting in a Fourier transform on s n exp(j2πΔft).
Figure PCTCN2014090876-appb-000003
The obtained S k ' is not equal to the S k transmitted by the transmitting end. It can be seen that the carrier frequency offset destroys the orthogonality between the subcarriers, and mutual interference between the subcarriers is generated, so that the receiving end cannot correctly demodulate the data from each subcarrier.
在OFDMA***中，每个用户发送的信号携带的载波频率偏移各不相同，导致接收端对接收到的信号进行DFT变换时获得的数据
Figure PCTCN2014090876-appb-000004
(其中p表示不同用户)；可以看出，OFDMA***接收端的子载波间干扰更为复杂，如何减小OFDMA***中子载波间干扰是一个迫切需要解决的问题。 In an OFDMA system, each user sends a signal carrying a different carrier frequency offset, resulting in data obtained by the receiving end when performing DFT conversion on the received signal.
Figure PCTCN2014090876-appb-000004
 (where p represents different users); it can be seen that the inter-subcarrier interference at the receiving end of the OFDMA system is more complicated. How to reduce the inter-subcarrier interference in the OFDMA system is an urgent problem to be solved.
发明内容Summary of the invention
本发明实施例提供一种OFDMA***中减小子载波间干扰的方法和装置，用以减小OFDMA***中子载波间干扰。Embodiments of the present invention provide a method and apparatus for reducing inter-subcarrier interference in an OFDMA system, which are used to reduce inter-subcarrier interference in an OFDMA system.
本发明实施例提供一种OFDMA***中减小子载波间干扰的方法，包括：An embodiment of the present invention provides a method for reducing inter-subcarrier interference in an OFDMA system, including:
根据用户设备所占用的子载波内的导频符号，估计所述用户设备的载波频率偏移值；Estimating a carrier frequency offset value of the user equipment according to a pilot symbol in a subcarrier occupied by the user equipment;
根据所述载波频率偏移值，确定所述用户设备对应的载波间干扰ICI消除滤波器系数；Determining, according to the carrier frequency offset value, an inter-carrier interference ICI cancellation filter coefficient corresponding to the user equipment;
通过所述ICI消除滤波器系数，对所述用户设备的频域数据进行滤波处理。Filtering the frequency domain data of the user equipment by using the ICI cancellation filter coefficients.
本发明实施例提供一种OFDMA***中减小子载波间干扰的装置，所述装置为访问节点AP或基站，包括：An embodiment of the present invention provides an apparatus for reducing inter-subcarrier interference in an OFDMA system, where the apparatus is an access node AP or a base station, and includes:
估计模块，用于根据用户设备所占用的子载波内的导频符号，估计所述用户设备的载波频率偏移值；An estimation module, configured to estimate a carrier frequency offset value of the user equipment according to a pilot symbol in a subcarrier occupied by the user equipment;
确定模块，用于根据所述载波频率偏移值，确定所述用户设备对应的载波间干扰ICI消除滤波器系数；a determining module, configured to determine, according to the carrier frequency offset value, an inter-carrier interference ICI cancellation filter coefficient corresponding to the user equipment;
滤波模块，用于通过所述ICI消除滤波器系数，对所述用户设备的频域数据进行滤波处理。And a filtering module, configured to perform filtering processing on the frequency domain data of the user equipment by using the ICI to eliminate filter coefficients.
本发明实施例提供一种OFDMA***中减小子载波间干扰的方法和装置，通过根据用户设备所占用的子载波内的导频符号，估计所述用户设备的载波频率偏移值；根据所述载波频率偏移值，确定所述用户设备对应的载波间干扰ICI消除滤波器系数；通过所述ICI消除滤波器系数，对所述用户设备的频域数据进行滤波处理；消除了所述用户设备所占用的子载波之间的干扰，从而减小OFDMA***中子载波间干扰。An embodiment of the present invention provides a method and apparatus for reducing inter-subcarrier interference in an OFDMA system, by estimating a carrier frequency offset value of the user equipment according to a pilot symbol in a subcarrier occupied by a user equipment; Determining an inter-carrier interference ICI cancellation filter coefficient corresponding to the user equipment, and performing filter processing on the frequency domain data of the user equipment by using the ICI cancellation filter coefficient; eliminating the user Interference between subcarriers occupied by the device, thereby reducing interference between subcarriers in the OFDMA system.
附图说明DRAWINGS
为了更清楚地说明本发明实施例或现有技术中的技术方案，下面将对实施例或现有技术描述中所需要使用的附图作一简单地介绍，显而易见地，下面描述中的附图是本发明的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。 In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, a brief description of the drawings used in the embodiments or the prior art description will be briefly described below. Obviously, the drawings in the following description It is a certain embodiment of the present invention, and other drawings can be obtained from those skilled in the art without any creative work.
图1为本发明OFDMA***中减小子载波间干扰的方法的应用场景示意图；1 is a schematic diagram of an application scenario of a method for reducing inter-subcarrier interference in an OFDMA system according to the present invention;
图2为本发明OFDMA***中减小子载波间干扰的方法实施例一的流程图；2 is a flowchart of Embodiment 1 of a method for reducing inter-subcarrier interference in an OFDMA system according to the present invention;
图3为本发明OFDMA***中减小子载波间干扰的方法实施例二的流程图；3 is a flowchart of Embodiment 2 of a method for reducing inter-subcarrier interference in an OFDMA system according to the present invention;
图4为本发明WLAN网络帧数据结构示意图一；4 is a schematic diagram 1 of a WLAN network frame data structure according to the present invention;
图5为本发明WLAN网络帧数据结构示意图二；5 is a schematic diagram 2 of a WLAN network frame data structure according to the present invention;
图6为本发明OFDMA***中减小子载波间干扰的方法实施例三的流程图；6 is a flowchart of Embodiment 3 of a method for reducing inter-subcarrier interference in an OFDMA system according to the present invention;
图7为本发明OFDMA***中减小子载波间干扰的装置实施例一的结构示意图；FIG. 7 is a schematic structural diagram of Embodiment 1 of an apparatus for reducing inter-subcarrier interference in an OFDMA system according to the present invention;
图8为本发明OFDMA***中减小子载波间干扰的装置实施例四的结构示意图。FIG. 8 is a schematic structural diagram of Embodiment 4 of an apparatus for reducing inter-subcarrier interference in an OFDMA system according to the present invention.
具体实施方式detailed description
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。The technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. It is a partial embodiment of the invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.
图1为本发明OFDMA***中减小子载波间干扰的方法的应用场景示意图，如图1所示，在无线局域网络(WLAN，Wireless Local Area Networks)中，各用户设备12占用不同的子载波集，并通过OFDMA的方式向访问节点(AP，Access Point)11发送数据；访问节点11同时接收多个用户设备12发送的数据。由于各用户设备12和访问节点11的振荡器不匹配，导致各用户设备12上变频时使用的载波频率与访问节点11下变频时使用的载波频率之间存在偏移；因此，对于访问节点11来说，如何在接收各用户设备12发送的数据时减小子载波间干扰是一个迫切需要解决的问题。1 is a schematic diagram of an application scenario of a method for reducing inter-subcarrier interference in an OFDMA system according to the present invention. As shown in FIG. 1, in a wireless local area network (WLAN), each user equipment 12 occupies different subcarriers. The data is transmitted to the access node (AP, Access Point) 11 by means of OFDMA; the access node 11 simultaneously receives data transmitted by the plurality of user equipments 12. Since the oscillators of the user equipment 12 and the access node 11 do not match, there is an offset between the carrier frequency used when each user equipment 12 is upconverted and the carrier frequency used when the access node 11 is downconverted; therefore, for the access node 11 Therefore, how to reduce inter-subcarrier interference when receiving data transmitted by each user equipment 12 is an urgent problem to be solved.
需要说明的是，本发明OFDMA***中减小子载波间干扰的方法的应用 场景也可以为长期演进(LTE，Long Term Evolution)网络，LTE网络中各用户设备通过OFDMA的方式向基站发送数据。It should be noted that the method for reducing inter-subcarrier interference in the OFDMA system of the present invention is applicable. The scenario may also be a Long Term Evolution (LTE) network. Each user equipment in the LTE network sends data to the base station by means of OFDMA.
图2为本发明OFDMA***中减小子载波间干扰的方法实施例一的流程图，如图2所示，本实施例的方法可以包括：2 is a flowchart of Embodiment 1 of a method for reducing inter-subcarrier interference in an OFDMA system according to the present invention. As shown in FIG. 2, the method in this embodiment may include:
步骤201、根据用户设备所占用的子载波内的导频符号，估计所述用户设备的载波频率偏移值；Step 201: Estimating a carrier frequency offset value of the user equipment according to a pilot symbol in a subcarrier occupied by the user equipment;
步骤202、根据所述载波频率偏移值，确定所述用户设备对应的载波间干扰ICI消除滤波器系数；Step 202: Determine, according to the carrier frequency offset value, an inter-carrier interference ICI cancellation filter coefficient corresponding to the user equipment.
步骤203、通过所述ICI消除滤波器系数，对所述用户设备的频域数据进行滤波处理。Step 203: Perform filter processing on the frequency domain data of the user equipment by using the ICI cancellation filter coefficient.
现有技术中，由于用户设备与接入节点(对于WLAN网络)或基站(对于LTE网络)之间的振荡器不匹配，用户设备上变频时使用的载波频率与接入节点或基站下变频时使用的载波频率之间存在偏移，载波频率偏移破坏了子载波间的正交性，产生了子载波间相互干扰。本发明中，接入节点或基站根据用户设备所占用的子载波内的导频符号，估计所述用户设备的载波频率偏移值；根据所述载波频率偏移值，确定所述用户设备对应的载波间干扰ICI消除滤波器系数；通过所述ICI消除滤波器系数，对所述用户设备的频域数据进行滤波处理。In the prior art, due to the oscillator mismatch between the user equipment and the access node (for the WLAN network) or the base station (for the LTE network), the carrier frequency used when the user equipment is up-converted and the access node or the base station are down-converted. There is an offset between the carrier frequencies used, and the carrier frequency offset destroys the orthogonality between the subcarriers, resulting in mutual interference between the subcarriers. In the present invention, the access node or the base station estimates the carrier frequency offset value of the user equipment according to the pilot symbol in the subcarrier occupied by the user equipment; and determines, according to the carrier frequency offset value, the user equipment corresponding Inter-carrier interference ICI cancellation filter coefficients; filtering the frequency domain data of the user equipment by filtering the filter coefficients by the ICI.
本发明中将对一用户设备所占用子载波的载波间干扰分为两部分，一部分为该用户设备所占用的子载波之间的干扰，另一部分为其他用户设备所占用的子载波对该用户设备所占用子载波的干扰。本发明通过实验确定，该用户设备所占用的子载波之间的干扰为导致接入节点或基站无法将该用户设备所占用子载波上的数据正确解调出的主要原因；因此，本发明通过接入节点或基站根据用户设备所占用的子载波内的导频符号，估计所述用户设备的载波频率偏移值；根据所述载波频率偏移值，确定所述用户设备对应的载波间干扰ICI消除滤波器系数；通过所述ICI消除滤波器系数，对所述用户设备的频域数据进行滤波处理；消除了所述用户设备所占用的子载波之间的干扰，从而减小OFDMA***中子载波间干扰。In the present invention, the inter-carrier interference of the subcarriers occupied by a user equipment is divided into two parts, one part is the interference between the subcarriers occupied by the user equipment, and the other part is the subcarrier occupied by other user equipments to the user. The interference of the subcarriers occupied by the device. The invention determines by experiments that the interference between the subcarriers occupied by the user equipment is the main reason that the access node or the base station cannot correctly demodulate the data on the subcarriers occupied by the user equipment; therefore, the present invention passes The access node or the base station estimates the carrier frequency offset value of the user equipment according to the pilot symbol in the subcarrier occupied by the user equipment, and determines the inter-carrier interference corresponding to the user equipment according to the carrier frequency offset value. Eliminating the filter coefficients by the ICI; filtering the frequency domain data of the user equipment by using the ICI cancellation filter coefficients; eliminating interference between subcarriers occupied by the user equipment, thereby reducing the OFDMA system Inter-subcarrier interference.
图3为本发明OFDMA***中减小子载波间干扰的方法实施例二的流程图，如图3所示，本实施例的方法可以包括： 3 is a flowchart of Embodiment 2 of a method for reducing inter-subcarrier interference in an OFDMA system according to the present invention. As shown in FIG. 3, the method in this embodiment may include:
步骤301、根据用户设备所占用的子载波内的导频符号，估计所述用户设备的载波频率偏移值；Step 301: Estimate a carrier frequency offset value of the user equipment according to a pilot symbol in a subcarrier occupied by the user equipment.
可选的，从训练序列或数据符号中获取至少两组导频信息；根据所述导频信息，采用如下公式(1)，获得载波频率偏移值CFO(est)：Optionally, at least two sets of pilot information are obtained from the training sequence or the data symbol; and according to the pilot information, the carrier frequency offset value CFO(est) is obtained by using the following formula (1):
Figure PCTCN2014090876-appb-000005
Figure PCTCN2014090876-appb-000005
其中，pilot1,n为第一组导频信息；pilot2,n为第二组导频信息；TimeDist为两组导频信息之间的时间间隔；n为正整数。Wherein, pilot 1, n is the first set of pilot information; pilot 2, n is the second set of pilot information; TimeDist is the time interval between the two sets of pilot information; n is a positive integer.
需要说明的是，本发明中conj函数用于求复数的共轭，arg函数用于求复数的辐角。It should be noted that in the present invention, the conj function is used to find the conjugate of the complex number, and the arg function is used to find the argument angle of the complex number.
可选的，从训练序列或数据符号中获取至少两组导频信息，包括：从第一训练序列和第二训练序列中分别获取一组导频信息；或者，从第一训练序列中获取一组导频信息，从第一数据符号中获取另一组导频信息；或者，从第一数据符号和第二数据符号中分别获取两组导频信息。Optionally, acquiring at least two sets of pilot information from the training sequence or the data symbol includes: acquiring a set of pilot information from the first training sequence and the second training sequence respectively; or acquiring one from the first training sequence. The group of pilot information acquires another set of pilot information from the first data symbol; or, the two sets of pilot information are respectively obtained from the first data symbol and the second data symbol.
需要说明的是，本发明中所获取的两组导频信息所处的子载波相同。It should be noted that the two sets of pilot information acquired in the present invention are in the same subcarrier.
可选的，当确定用户设备占用的一子载波上该用户数据的一帧数据中存在两个或两个以上的训练序列时，可以从任意两个训练序列中分别获取一组导频信息，时间位置靠前的一组导频信息作为第一组导频信息，时间位置靠后的一组导频信息作为第二组导频信息。Optionally, when it is determined that two or more training sequences exist in one frame of the user data on a subcarrier occupied by the user equipment, a set of pilot information may be separately obtained from any two training sequences. The first set of pilot information of the time position is used as the first group of pilot information, and the set of pilot information of the later time position is used as the second group of pilot information.
图4为本发明WLAN网络帧数据结构示意图一，如图4所示，该帧数据中存在两个以上的训练序列，可以从长码部分(LTF，long training field)1中获取第一组导频信息，从LTF2中获取第二组导频信息。4 is a schematic diagram 1 of a WLAN network frame data structure according to the present invention. As shown in FIG. 4, there are two or more training sequences in the frame data, and the first group guide can be obtained from a long training field (LTF) 1 Frequency information, obtaining a second set of pilot information from LTF2.
假设用户设备1所占用的载波位置为0～55，载波位置为7、21、34、48的子载波上承载了用于频偏估计的信息，则从LTF1中获取的第一组导频信息可以分别为载波位置为7、21、34、48的子载波上分别所承载的信息：pilot1,1、pilot1,2、pilot1,3、pilot1,4；从LTF2中获取的第二组导频信息也可以分别为载波位置为7、21、34、48的子载波上分别所承载的信息：pilot2,1、pilot2,2、pilot2,3、pilot2,4。Assuming that the carrier position occupied by the user equipment 1 is 0-55, and the carrier position is 7, 21, 34, 48, the first set of pilot information acquired from the LTF1 is carried. The information carried on the subcarriers with carrier positions of 7, 21, 34, 48 respectively: pilot 1,1 , pilot 1,2 , pilot 1,3 , pilot 1,4 ; the second obtained from LTF2 The group pilot information may also be information carried on subcarriers with carrier positions of 7, 21, 34, 48 respectively: pilot 2,1 , pilot 2,2 , pilot 2,3 , pilot 2,4 .
可以看出，当从第一训练序列和第二训练序列中分别获取一组导频信息时：对于同一用户设备两组导频信息所处的载波位置应相同。 It can be seen that when a set of pilot information is respectively obtained from the first training sequence and the second training sequence, the carrier positions of the two sets of pilot information for the same user equipment should be the same.
需要说明的是，当帧数据中存在两个以上训练序列时，也可以仅从数据符号中获取导频信息；或者，从训练序列中获取一组导频信息，从数据符号中获取另一组导频信息。It should be noted that when there are more than two training sequences in the frame data, the pilot information may also be obtained only from the data symbols; or, one set of pilot information is obtained from the training sequence, and another group is obtained from the data symbols. Pilot information.
可选的，当确定用户设备占用的一子载波上该用户设备的一帧数据中仅存在一个训练序列时，可以从该训练序列和任意一个数据符号中分别获取一组导频信息。Optionally, when it is determined that only one training sequence exists in one frame of data of the user equipment on a subcarrier occupied by the user equipment, a set of pilot information may be separately obtained from the training sequence and any one of the data symbols.
图5为本发明WLAN网络帧数据结构示意图二，如图5所示，该帧数据中存在一个训练序列，可以从LTF1中获取第一组导频信息，从数据符号DATA1中获取第二组导频信息。FIG. 5 is a schematic diagram 2 of a WLAN network frame data structure according to the present invention. As shown in FIG. 5, there is a training sequence in the frame data, and the first group of pilot information may be obtained from the LTF1, and the second group guide is obtained from the data symbol DATA1. Frequency information.
假设用户设备1所占用的载波位置为0～55，载波位置为7、21、34、48的子载波上承载了用于频偏估计的信息，则从LTF1中获取的第一组导频信息可以分别为载波位置为7、21、34、48的子载波上分别所承载的信息：pilot1,1、pilot1,2、pilot1,3、pilot1,4；从DATA1中获取的第二组导频信息也可以分别为载波位置为7、21、34、48的子载波上分别所承载的信息：pilot2,1、pilot2,2、pilot2,3、pilot2,4。Assuming that the carrier position occupied by the user equipment 1 is 0-55, and the carrier position is 7, 21, 34, 48, the first set of pilot information acquired from the LTF1 is carried. The information carried on the subcarriers with carrier positions of 7, 21, 34, 48 respectively: pilot 1,1 , pilot 1,2 , pilot 1,3 , pilot 1,4 ; the second obtained from DATA1 The group pilot information may also be information carried on subcarriers with carrier positions of 7, 21, 34, 48 respectively: pilot 2,1 , pilot 2,2 , pilot 2,3 , pilot 2,4 .
可以看出，当从第一训练序列中获取一组导频信息，从第一数据符号中获取另一组导频信息时：对于同一用户设备两组导频信息所处的载波位置也应相同。It can be seen that when acquiring one set of pilot information from the first training sequence and acquiring another set of pilot information from the first data symbol: the carrier position of the two sets of pilot information for the same user equipment should also be the same .
可选的，当确定用户设备占用的一子载波上该用户设备的一帧数据中不存在训练序列时，可以从任意两个数据符号分别获取一组导频信息，时间位置靠前的一组导频信息作为第一组导频信息，时间位置靠后的一组导频信息作为第二组导频信息。Optionally, when it is determined that there is no training sequence in a frame of data of the user equipment on a subcarrier occupied by the user equipment, a set of pilot information may be obtained from any two data symbols, and the group of time positions is forwarded. The pilot information is used as the first group of pilot information, and the set of pilot information at the time position is used as the second group of pilot information.
例如，对于WLAN网络，可以从DATA1中获取第一组导频信息，从DATA2中获取第二组导频信息。For example, for a WLAN network, a first set of pilot information can be obtained from DATA1 and a second set of pilot information can be obtained from DATA2.
对于同一用户设备所占用的各个子载波来说，由该用户设备与接收端的振荡器之间的不匹配所造成的该用户设备上变频时使用的载波频域与接收端下变频时使用的载波频率之间存在的偏移相同，即同一用户设备所占用的各子载波具有相同的载波频率偏移。因此，本发明中仅获取通过该用户设备所占用的任一子载波上的两组导频信息，便可以获取该用户设备所有子载波的载波频率偏移。 For each subcarrier occupied by the same user equipment, the carrier frequency domain used in the up-conversion of the user equipment and the carrier used in the down-conversion of the receiving end caused by the mismatch between the user equipment and the oscillator of the receiving end The offsets between the frequencies are the same, that is, each subcarrier occupied by the same user equipment has the same carrier frequency offset. Therefore, in the present invention, only the two sets of pilot information on any subcarrier occupied by the user equipment are acquired, and the carrier frequency offset of all subcarriers of the user equipment can be acquired.
步骤302、根据所述载波频率偏移值和所述用户设备进行FFT变换时所使用的FFT点数，计算所述用户设备对应的ICI消除滤波器系数；Step 302: Calculate an ICI cancellation filter coefficient corresponding to the user equipment according to the carrier frequency offset value and the number of FFT points used by the user equipment to perform FFT transformation;
可选的，根据所述载波频率偏移值和所述用户设备进行快速傅利叶变换(FFT，Fast Fourier Transformation)变换时所使用的FFT点数，采用如下公式(2)，计算所述用户设备对应的ICI消除滤波器系数WFilterTap：Optionally, calculating, according to the carrier frequency offset value and the number of FFT points used by the user equipment to perform Fast Fourier Transformation (FFT), using the following formula (2), calculating corresponding to the user equipment. ICI Elimination Filter Coefficient W FilterTap :
Figure PCTCN2014090876-appb-000006
Figure PCTCN2014090876-appb-000006
其中，N为FFT点数、Ntap为滤波器抽头系数；ω＝2π×CFO(est)，CFO(est)为载波频率偏移值。Where N is the number of FFT points, N tap is the filter tap coefficient; ω=2π×CFO(est), and CFO(est) is the carrier frequency offset value.
例如，若FFT点数N为256，估计出的CFO(est)为367.3Hz，滤波器抽头数Ntap为21；则根据公式(2)，可以获得ICI消除滤波器系数WFilterTap为：For example, if the number of FFT points N is 256, the estimated CFO(est) is 367.3 Hz, and the number of filter taps N tap is 21, then according to formula (2), the ICI cancellation filter coefficient W FilterTap can be obtained as:
WFilterTap＝{-0.0005+0.0001i -0.0005+0.0001i -0.0006+0.0001i-0.0007+0.0001i -0.0008+0.0001i -0.0009+0.0001i-0.0012+0.0001i-0.0016+0.0001i -0.0024+0.0001i -0.0047+0.0001i 1.00000.0047+0.0001i 0.0023+0.0001i 0.0016+0.0001i 0.0012+0.0001i0.0009+0.0001i 0.0008+0.0001i 0.0007+0.0001i 0.0006+0.0001i0.0005+0.0001i 0.0005+0.0001i}W FilterTap ={-0.0005+0.0001i -0.0005+0.0001i -0.0006+0.0001i-0.0007+0.0001i -0.0008+0.0001i -0.0009+0.0001i-0.0012+0.0001i-0.0016+0.0001i -0.0024+0.0001i - 0.0047+0.0001i 1.00000.0047+0.0001i 0.0023+0.0001i 0.0016+0.0001i 0.0012+0.0001i0.0009+0.0001i 0.0008+0.0001i 0.0007+0.0001i 0.0006+0.0001i0.0005+0.0001i 0.0005+0.0001i}
步骤303、通过所述ICI消除滤波器系数，对所述用户设备的频域数据进行滤波处理。Step 303: Perform filter processing on the frequency domain data of the user equipment by using the ICI cancellation filter coefficient.
具体的，将获得的ICI消除滤波器系数与接收到的所述用户设备的频域数据进行卷积。Specifically, the obtained ICI cancellation filter coefficient is convoluted with the received frequency domain data of the user equipment.
例如，若用户设备的频域数据为{y1,y2,y3,...yN}，选取的ICI消除滤波器系数为{w-10,w-9,...,w0,...w10}，则对所述用户设备的频域数据进行卷积后的数据为{x1,x2,x3,...xN}；For example, if the frequency domain data of the user equipment is {y 1 , y 2 , y 3 , ... y N }, the selected ICI cancellation filter coefficients are {w -10 , w -9 ,...,w 0 , ...w 10 }, the data after convolution of the frequency domain data of the user equipment is {x 1 , x 2 , x 3 , ... x N };
其中： among them:
Figure PCTCN2014090876-appb-000007
Figure PCTCN2014090876-appb-000007
Figure PCTCN2014090876-appb-000008
Figure PCTCN2014090876-appb-000008
本发明通过根据用户设备所占用的子载波内的导频符号，估计所述用户设备的载波频率偏移值；根据所述载波频率偏移值和所述用户设备进行FFT变换时所使用的FFT点数，计算所述用户设备对应的ICI消除滤波器系数；通过所述ICI消除滤波器系数，对所述用户设备的频域数据进行滤波处理；消除了所述用户设备所占用的子载波之间的干扰，从而减小OFDMA***中子载波间干扰。同时，解决了接收端无法从各个子载波上正确地解调出数据的问题。The present invention estimates a carrier frequency offset value of the user equipment according to a pilot symbol in a subcarrier occupied by the user equipment; and uses an FFT used according to the carrier frequency offset value and the user equipment to perform FFT transformation. Counting, calculating an ICI cancellation filter coefficient corresponding to the user equipment; performing filter processing on the frequency domain data of the user equipment by using the ICI cancellation filter coefficient; eliminating between subcarriers occupied by the user equipment Interference, thereby reducing inter-subcarrier interference in an OFDMA system. At the same time, the problem that the receiving end cannot correctly demodulate data from each subcarrier is solved.
图6为本发明OFDMA***中减小子载波间干扰的方法实施例三的流程图，如图6所示，本实施例的方法可以包括：FIG. 6 is a flowchart of Embodiment 3 of a method for reducing inter-subcarrier interference in an OFDMA system according to the present invention. As shown in FIG. 6, the method in this embodiment may include:
步骤601、根据用户设备所占用的子载波内的导频符号，估计所述用户设备的载波频率偏移值；Step 601: Estimate a carrier frequency offset value of the user equipment according to a pilot symbol in a subcarrier occupied by the user equipment.
需要说明的是，步骤601与步骤301相同，在此不再赘述。It should be noted that step 601 is the same as step 301, and details are not described herein again.
步骤602、根据所述载波频率偏移值和所述用户设备进行FFT变换时所使用的FFT点数，从预先存储的ICI消除滤波器系数中选择所述用户设备对应的ICI消除滤波器系数；Step 602: Select, according to the carrier frequency offset value and the number of FFT points used by the user equipment to perform FFT transformation, the ICI cancellation filter coefficient corresponding to the user equipment from the pre-stored ICI cancellation filter coefficients;
可选的，根据所述载波频率偏移值、所述用户设备进行FFT变换时所使用的FFT点数和预设的滤波器抽头系数，采用FFT点数匹配、滤波器抽头系数匹配及载波频率偏移值距离最近原则，从预先存储的ICI消除滤波器系数中选择所述用户设备对应的ICI消除滤波器系数。Optionally, the FFT point matching, the filter tap coefficient matching, and the carrier frequency offset are used according to the carrier frequency offset value, the FFT point used by the user equipment for performing FFT transformation, and a preset filter tap coefficient. The value distance closest principle selects the ICI cancellation filter coefficient corresponding to the user equipment from the pre-stored ICI cancellation filter coefficients.
例如，若FFT点数为256，估计出的CFO(est)为367.3KHz，FFT点数为 256、滤波器抽头系数为21对应的预先存储的ICI消除滤波器系数如表1所示；则可以看出CFO(pre)＝400Hz与CFO(est)距离最近，可以获得ICI消除滤波器系数为：For example, if the number of FFT points is 256, the estimated CFO(est) is 367.3KHz, and the number of FFT points is 256. The pre-stored ICI cancellation filter coefficients corresponding to the filter tap coefficient of 21 are as shown in Table 1. It can be seen that the CFO(pre)=400Hz is closest to the CFO(est), and the ICI cancellation filter coefficient can be obtained as :
ICI-Filter＝{-0.0005+0.0001i -0.0006+0.0001i -0.0006+0.0001i-0.0007+0.0001i -0.0009+0.0001i -0.0010+0.0001i -0.0013+0.0001i-0.0017+0.0001i -0.0026+0.0001i -0.0051+0.0001i 1.00000.0051+0.0001i 0.0026+0.0001i 0.0017+0.0001i 0.0013+0.0001i0.0010+0.0001i 0.0009+0.0001i 0.0007+0.0001i 0.0006+0.0001i0.0006+0.0001i 0.0005+0.0001i}ICI-Filter={-0.0005+0.0001i -0.0006+0.0001i -0.0006+0.0001i-0.0007+0.0001i -0.0009+0.0001i -0.0010+0.0001i -0.0013+0.0001i-0.0017+0.0001i -0.0026+0.0001i -0.0051+0.0001i 1.00000.0051+0.0001i 0.0026+0.0001i 0.0017+0.0001i 0.0013+0.0001i0.0010+0.0001i 0.0009+0.0001i 0.0007+0.0001i 0.0006+0.0001i0.0006+0.0001i 0.0005+0.0001i}
又例如，若FFT点数为256，估计出的CFO(est)＝-367.3KHz，FFT点数为256、滤波器抽头系数为21对应的预先存储的ICI消除滤波器系数如表1所示；则可以看出CFO(pre)＝-400Hz与CFO(est)距离接近，可以获得ICI消除滤波器系数为：For example, if the number of FFT points is 256, the estimated CFO(est)=-367.3KHz, the FFT point number is 256, and the pre-stored ICI cancellation filter coefficient corresponding to the filter tap coefficient is 21; It can be seen that the CFO(pre)=-400Hz is close to the CFO(est), and the ICI cancellation filter coefficient can be obtained as:
ICI-Filter＝{0.0005-0.0001i 0.0006-0.0001i 0.0006-0.0001i0.0007-0.0001i 0.0009-0.0001i 0.0010-0.0001i 0.0013-0.0001i0.0017-0.0001i 0.0026-0.0001i 0.0051-0.0001i 1.0000-0.0051-0.0001i -0.0026-0.0001i -0.0017-0.0001i -0.0013-0.0001i-0.0010-0.0001i -0.0009-0.0001i -0.0007-0.0001i -0.0006-0.0001i-0.0006-0.0001i -0.0005-0.0001i}ICI-Filter={0.0005-0.0001i 0.0006-0.0001i 0.0006-0.0001i0.0007-0.0001i 0.0009-0.0001i 0.0010-0.0001i 0.0013-0.0001i0.0017-0.0001i 0.0026-0.0001i 0.0051-0.0001i 1.0000-0.0051 -0.0001i -0.0026-0.0001i -0.0017-0.0001i -0.0013-0.0001i-0.0010-0.0001i -0.0009-0.0001i -0.0007-0.0001i -0.0006-0.0001i-0.0006-0.0001i -0.0005-0.0001i}
表1(FFT＝256)Table 1 (FFT=256)
Figure PCTCN2014090876-appb-000009
Figure PCTCN2014090876-appb-000009
Figure PCTCN2014090876-appb-000010
Figure PCTCN2014090876-appb-000010
步骤603、通过所述ICI消除滤波器系数，对所述用户设备的频域数据进行滤波处理。Step 603: Perform filter processing on the frequency domain data of the user equipment by using the ICI cancellation filter coefficient.
需要说明的是，步骤603与步骤303相同，在此不再赘述。It should be noted that step 603 is the same as step 303, and details are not described herein again.
本发明通过根据用户设备所占用的子载波内的导频符号，估计所述用户设备的载波频率偏移值；根据所述载波频率偏移值、所述用户设备进行FFT变换时所使用的FFT点数和预设的滤波器抽头系数，从预先存储的ICI消除滤波器系数中选择所述用户设备对应的ICI消除滤波器系数；通过所述ICI消除滤波器系数，对所述用户设备的频域数据进行滤波处理；消除了所述用户设备所占用的子载波之间的干扰，从而减小OFDMA***中子载波间干扰。同时，解决了接收端无法从各个子载波上正确地解调出数据的问题。The present invention estimates a carrier frequency offset value of the user equipment according to a pilot symbol in a subcarrier occupied by the user equipment; and uses an FFT used by the user equipment to perform FFT transformation according to the carrier frequency offset value. a point and a preset filter tap coefficient, selecting an ICI cancellation filter coefficient corresponding to the user equipment from pre-stored ICI cancellation filter coefficients; removing a filter coefficient by the ICI, and frequency domain of the user equipment The data is subjected to filtering processing; interference between subcarriers occupied by the user equipment is eliminated, thereby reducing inter-subcarrier interference in the OFDMA system. At the same time, the problem that the receiving end cannot correctly demodulate data from each subcarrier is solved.
图7为本发明OFDMA***中减小子载波间干扰的装置实施例一的结构示意图，该装置可以为WLAN网络中的访问节点或LTE网络中的基站，如图7所示，本实施例的装置可以包括：估计模块701、确定模块702和滤波模块703。其中，估计模块701，用于根据用户设备所占用的子载波内的导频符号，估计所述用户设备的载波频率偏移值；确定模块702，用于根据所述载波频率偏移值，确定所述用户设备对应的载波间干扰ICI消除滤波器系数；滤波模块703，用于通过所述ICI消除滤波器系数，对所述用户设备的频域数据进行滤波处理。FIG. 7 is a schematic structural diagram of Embodiment 1 of an apparatus for reducing inter-subcarrier interference in an OFDMA system according to the present invention. The apparatus may be an access node in a WLAN network or a base station in an LTE network, as shown in FIG. The apparatus may include an estimation module 701, a determination module 702, and a filtering module 703. The estimating module 701 is configured to estimate a carrier frequency offset value of the user equipment according to a pilot symbol in a subcarrier occupied by the user equipment, where the determining module 702 is configured to determine, according to the carrier frequency offset value, The inter-carrier interference ICI cancellation filter coefficient corresponding to the user equipment; the filtering module 703 is configured to filter the frequency domain data of the user equipment by using the ICI cancellation filter coefficient.
本实施例的装置，可以用于执行图2所示方法实施例的技术方案，其实现原理和技术效果类似，此处不再赘述。The device in this embodiment may be used to implement the technical solution of the method embodiment shown in FIG. 2, and the implementation principle and technical effects are similar, and details are not described herein again.
OFDMA***中减小子载波间干扰的装置实施例二Apparatus for reducing inter-subcarrier interference in an OFDMA system
在本发明OFDMA***中减小子载波间干扰的装置实施例一的基础上，可选的，估计模块701，具体用于：In the first embodiment of the apparatus for reducing inter-subcarrier interference in the OFDMA system of the present invention, optionally, the estimating module 701 is specifically configured to:
从训练序列或数据符号中获取至少两组导频信息； Obtaining at least two sets of pilot information from a training sequence or a data symbol;
根据所述导频信息，采用如下公式(1)，获得载波频率偏移值CFO(est)：According to the pilot information, the carrier frequency offset value CFO(est) is obtained by using the following formula (1):
Figure PCTCN2014090876-appb-000011
Figure PCTCN2014090876-appb-000011
其中，pilot1,n为第一组导频信息；pilot2,n为第二组导频信息；TimeDist为两组导频信息之间的时间间隔；n为正整数。Wherein, pilot 1, n is the first set of pilot information; pilot 2, n is the second set of pilot information; TimeDist is the time interval between the two sets of pilot information; n is a positive integer.
进一步可选的，估计模块701，具体用于：从第一训练序列和第二训练序列中分别获取一组导频信息；或者，从第一训练序列中获取一组导频信息，从第一数据符号中获取另一组导频信息；或者，从第一数据符号和第二数据符号中分别获取两组导频信息。Further, the estimating module 701 is specifically configured to: obtain a set of pilot information from the first training sequence and the second training sequence respectively; or obtain a set of pilot information from the first training sequence, from the first Another set of pilot information is acquired in the data symbol; or two sets of pilot information are respectively obtained from the first data symbol and the second data symbol.
可选的，确定模块702，具体用于：根据所述载波频率偏移值和所述用户设备进行FFT变换时所使用的FFT点数，计算所述用户设备对应的ICI消除滤波器系数。Optionally, the determining module 702 is configured to calculate an ICI cancellation filter coefficient corresponding to the user equipment according to the carrier frequency offset value and an FFT point used by the user equipment to perform FFT transformation.
进一步可选的，确定模块702，具体用于：Further optionally, the determining module 702 is specifically configured to:
根据所述载波频率偏移值和所述用户设备进行FFT变换时所使用的FFT点数，采用如下公式(2)，计算所述用户设备对应的ICI消除滤波器系数WFilterTap：When performing an FFT of FFT points according to the carrier frequency offset value and used by the user equipment, using the following formula (2), the user computing device corresponding to ICI cancellation filter coefficients W FilterTap:
Figure PCTCN2014090876-appb-000012
Figure PCTCN2014090876-appb-000012
其中，N为FFT点数、Ntap为滤波器抽头系数；ω＝2π×CFO(est)，CFO(est)为载波频率偏移值。Where N is the number of FFT points, N tap is the filter tap coefficient; ω=2π×CFO(est), and CFO(est) is the carrier frequency offset value.
本实施例的装置，可以用于执行图3所示方法实施例的技术方案，其实现原理和技术效果类似，此处不再赘述。The device in this embodiment may be used to implement the technical solution of the method embodiment shown in FIG. 3, and the implementation principle and technical effects are similar, and details are not described herein again.
OFDMA***中减小子载波间干扰的装置实施例三Apparatus for reducing inter-subcarrier interference in an OFDMA system
在本发明OFDMA***中减小子载波间干扰的装置实施例一的基础上，可选的，估计模块701，具体用于：In the first embodiment of the apparatus for reducing inter-subcarrier interference in the OFDMA system of the present invention, optionally, the estimating module 701 is specifically configured to:
从训练序列或数据符号中获取至少两组导频信息；Obtaining at least two sets of pilot information from a training sequence or a data symbol;
根据所述导频信息，采用如下公式(1)，获得载波频率偏移值CFO(est)：According to the pilot information, the carrier frequency offset value CFO(est) is obtained by using the following formula (1):
Figure PCTCN2014090876-appb-000013
Figure PCTCN2014090876-appb-000013
其中，pilot1,n为第一组导频信息；pilot2,n为第二组导频信息；TimeDist为两组导频信息之间的时间间隔；n为正整数。Wherein, pilot 1, n is the first set of pilot information; pilot 2, n is the second set of pilot information; TimeDist is the time interval between the two sets of pilot information; n is a positive integer.
进一步可选的，估计模块701，具体用于：从第一训练序列和第二训练序列中分别获取一组导频信息；或者，从第一训练序列中获取一组导频信息，从第一数据符号中获取另一组导频信息；或者，从第一数据符号和第二数据符号中分别获取两组导频信息。Further, the estimating module 701 is specifically configured to: obtain a set of pilot information from the first training sequence and the second training sequence respectively; or obtain a set of pilot information from the first training sequence, from the first Another set of pilot information is acquired in the data symbol; or two sets of pilot information are respectively obtained from the first data symbol and the second data symbol.
可选的，确定模块702，具体用于：Optionally, the determining module 702 is specifically configured to:
根据所述载波频率偏移值和所述用户设备进行FFT变换时所使用的FFT点数，从预先存储的ICI消除滤波器系数中选择所述用户设备对应的ICI消除滤波器系数。And selecting an ICI cancellation filter coefficient corresponding to the user equipment from the pre-stored ICI cancellation filter coefficients according to the carrier frequency offset value and the number of FFT points used by the user equipment for performing FFT transformation.
进一步可选的，确定模块702，具体用于：根据所述载波频率偏移值、所述用户设备进行FFT变换时所使用的FFT点数和预设的滤波器抽头系数，采用FFT点数匹配、滤波器抽头系数匹配及载波频率偏移值距离最近原则，从预先存储的ICI消除滤波器系数中选择所述用户设备对应的ICI消除滤波器系数。Further, the determining module 702 is specifically configured to: perform FFT point matching and filtering according to the carrier frequency offset value, the FFT point used by the user equipment for performing FFT transformation, and a preset filter tap coefficient. The tap coefficient matching and the carrier frequency offset value are closest to the principle, and the ICI cancellation filter coefficient corresponding to the user equipment is selected from the pre-stored ICI cancellation filter coefficients.
本实施例的装置，可以用于执行图6所示方法实施例的技术方案，其实现原理和技术效果类似，此处不再赘述。The device in this embodiment may be used to implement the technical solution of the method embodiment shown in FIG. 6. The implementation principle and technical effects are similar, and details are not described herein again.
图8为本发明OFDMA***中减小子载波间干扰的装置实施例四的结构示意图，该装置可以为WLAN网络中的访问节点或LTE网络中的基站，如图8所示，本实施例的装置可以包括：处理器801和存储器802。该装置还可以包括发射器803、接收器804。发射器803和接收器804可以和处理器801相连。其中，发射器803用于发送数据或信息，接收器804用于接收数据或信息，存储器802存储执行指令，当装置运行时，处理器801与存储器802之间通信，处理器801调用存储器802中的执行指令，用于执行以下操作：FIG. 8 is a schematic structural diagram of Embodiment 4 of an apparatus for reducing inter-subcarrier interference in an OFDMA system according to the present invention. The apparatus may be an access node in a WLAN network or a base station in an LTE network, as shown in FIG. The apparatus can include a processor 801 and a memory 802. The apparatus can also include a transmitter 803 and a receiver 804. Transmitter 803 and receiver 804 can be coupled to processor 801. The transmitter 803 is configured to transmit data or information, the receiver 804 is configured to receive data or information, the memory 802 stores execution instructions, when the device is in operation, the processor 801 communicates with the memory 802, and the processor 801 calls the memory 802. Execution instructions for performing the following operations:
根据用户设备所占用的子载波内的导频符号，估计所述用户设备的载波频率偏移值；Estimating a carrier frequency offset value of the user equipment according to a pilot symbol in a subcarrier occupied by the user equipment;
根据所述载波频率偏移值，确定所述用户设备对应的载波间干扰ICI消除滤波器系数；Determining, according to the carrier frequency offset value, an inter-carrier interference ICI cancellation filter coefficient corresponding to the user equipment;
通过所述ICI消除滤波器系数，对所述用户设备的频域数据进行滤波处 理。Filtering the frequency domain data of the user equipment by using the ICI cancellation filter coefficient Reason.
可选的，所述根据用户设备所占用的子载波内的导频符号，估计所述用户设备的载波频率偏移值，包括：Optionally, the estimating a carrier frequency offset value of the user equipment according to the pilot symbol in the subcarrier occupied by the user equipment, including:
从训练序列或数据符号中获取至少两组导频信息；Obtaining at least two sets of pilot information from a training sequence or a data symbol;
根据所述导频信息，采用如下公式(1)，获得载波频率偏移值CFO(est)：According to the pilot information, the carrier frequency offset value CFO(est) is obtained by using the following formula (1):
Figure PCTCN2014090876-appb-000014
Figure PCTCN2014090876-appb-000014
其中，pilot1,n为第一组导频信息；pilot2,n为第二组导频信息；TimeDist为两组导频信息之间的时间间隔；n为正整数。Wherein, pilot 1, n is the first set of pilot information; pilot 2, n is the second set of pilot information; TimeDist is the time interval between the two sets of pilot information; n is a positive integer.
可选的，所述从训练序列或数据符号中获取至少两组导频信息，包括：Optionally, the obtaining at least two sets of pilot information from the training sequence or the data symbol includes:
从第一训练序列和第二训练序列中分别获取一组导频信息；Obtaining a set of pilot information from the first training sequence and the second training sequence respectively;
或者，从第一训练序列中获取一组导频信息，从第一数据符号中获取另一组导频信息；Or acquiring a set of pilot information from the first training sequence, and acquiring another set of pilot information from the first data symbol;
或者，从第一数据符号和第二数据符号中分别获取两组导频信息。Alternatively, two sets of pilot information are respectively obtained from the first data symbol and the second data symbol.
可选的，所述根据所述载波频率偏移值，确定所述用户设备对应的载波间干扰ICI消除滤波器系数，包括：Optionally, the determining, according to the carrier frequency offset value, the inter-carrier interference ICI cancellation filter coefficient corresponding to the user equipment, including:
根据所述载波频率偏移值和所述用户设备进行快速傅利叶变换FFT变换时所使用的FFT点数，计算所述用户设备对应的ICI消除滤波器系数；Calculating, according to the carrier frequency offset value and the number of FFT points used by the user equipment to perform fast Fourier transform FFT transform, calculating an ICI cancellation filter coefficient corresponding to the user equipment;
或者，or,
根据所述载波频率偏移值和所述用户设备进行FFT变换时所使用的FFT点数，从预先存储的ICI消除滤波器系数中选择所述用户设备对应的ICI消除滤波器系数。And selecting an ICI cancellation filter coefficient corresponding to the user equipment from the pre-stored ICI cancellation filter coefficients according to the carrier frequency offset value and the number of FFT points used by the user equipment for performing FFT transformation.
可选的，根据所述载波频率偏移值和所述用户设备进行FFT变换时所使用的FFT点数，计算所述用户设备对应的ICI消除滤波器系数，包括：Optionally, calculating an ICI cancellation filter coefficient corresponding to the user equipment according to the carrier frequency offset value and the number of FFT points used by the user equipment to perform FFT transformation, including:
根据所述载波频率偏移值和所述用户设备进行FFT变换时所使用的FFT点数，采用如下公式(2)，计算所述用户设备对应的ICI消除滤波器系数WFilterTap：Calculating an ICI cancellation filter coefficient W FilterTap corresponding to the user equipment by using the following formula (2) according to the carrier frequency offset value and the number of FFT points used by the user equipment for performing FFT transformation:
Figure PCTCN2014090876-appb-000015
Figure PCTCN2014090876-appb-000015
其中，N为FFT点数、Ntap为滤波器抽头系数；ω＝2π×CFO(est)，CFO(est)为载波频率偏移值。Where N is the number of FFT points, N tap is the filter tap coefficient; ω=2π×CFO(est), and CFO(est) is the carrier frequency offset value.
可选的，根据所述载波频率偏移值和所述用户设备进行FFT变换时所使用的FFT点数，从预先存储的ICI消除滤波器系数中选择所述用户设备对应的ICI消除滤波器系数，包括：Optionally, the ICI cancellation filter coefficient corresponding to the user equipment is selected from the pre-stored ICI cancellation filter coefficients according to the carrier frequency offset value and the number of FFT points used by the user equipment for performing FFT transformation. include:
根据所述载波频率偏移值、所述用户设备进行FFT变换时所使用的FFT点数和预设的滤波器抽头系数，采用FFT点数匹配、滤波器抽头系数匹配及载波频率偏移值距离最近原则，从预先存储的ICI消除滤波器系数中选择所述用户设备对应的ICI消除滤波器系数。According to the carrier frequency offset value, the number of FFT points used by the user equipment for performing FFT transformation, and the preset filter tap coefficient, the FFT point matching, the filter tap coefficient matching, and the carrier frequency offset value distance nearest principle are adopted. And selecting an ICI cancellation filter coefficient corresponding to the user equipment from the pre-stored ICI cancellation filter coefficients.
本实施例的基站，可以用于执行本发明任意实施例所提供的OFDMA***中减小子载波间干扰的方法的技术方案，其实现原理和技术效果类似，此处不再赘述。The base station of this embodiment may be used to perform the technical solution for reducing the inter-subcarrier interference in the OFDMA system provided by any embodiment of the present invention. The implementation principle and technical effects are similar, and details are not described herein again.
本领域普通技术人员可以理解：实现上述各方法实施例的全部或部分步骤可以通过程序指令相关的硬件来完成。前述的程序可以存储于一计算机可读取存储介质中。该程序在执行时，执行包括上述各方法实施例的步骤；而前述的存储介质包括：ROM、RAM、磁碟或者光盘等各种可以存储程序代码的介质。One of ordinary skill in the art will appreciate that all or part of the steps to implement the various method embodiments described above may be accomplished by hardware associated with the program instructions. The aforementioned program can be stored in a computer readable storage medium. The program, when executed, performs the steps including the foregoing method embodiments; and the foregoing storage medium includes various media that can store program codes, such as a ROM, a RAM, a magnetic disk, or an optical disk.
最后应说明的是：以上各实施例仅用以说明本发明的技术方案，而非对其限制；尽管参照前述各实施例对本发明进行了详细的说明，本领域的普通技术人员应当理解：其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分或者全部技术特征进行等同替换；而这些修改或者替换，并不使相应技术方案的本质脱离本发明各实施例技术方案的范围。 Finally, it should be noted that the above embodiments are merely illustrative of the technical solutions of the present invention, and are not intended to be limiting; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art will understand that The technical solutions described in the foregoing embodiments may be modified, or some or all of the technical features may be equivalently replaced; and the modifications or substitutions do not deviate from the technical solutions of the embodiments of the present invention. range.

Claims (12)

  1. 一种正交频分多址OFDMA***中减小子载波间干扰的方法，其特征在于，包括：A method for reducing inter-subcarrier interference in an orthogonal frequency division multiple access OFDMA system, comprising:
    根据用户设备所占用的子载波内的导频符号，估计所述用户设备的载波频率偏移值；Estimating a carrier frequency offset value of the user equipment according to a pilot symbol in a subcarrier occupied by the user equipment;
    根据所述载波频率偏移值，确定所述用户设备对应的载波间干扰ICI消除滤波器系数；Determining, according to the carrier frequency offset value, an inter-carrier interference ICI cancellation filter coefficient corresponding to the user equipment;
    通过所述ICI消除滤波器系数，对所述用户设备的频域数据进行滤波处理。Filtering the frequency domain data of the user equipment by using the ICI cancellation filter coefficients.
  2. 根据权利要求1所述的方法，其特征在于，所述根据用户设备所占用的子载波内的导频符号，估计所述用户设备的载波频率偏移值，包括：The method according to claim 1, wherein the estimating a carrier frequency offset value of the user equipment according to a pilot symbol in a subcarrier occupied by a user equipment includes:
    从训练序列或数据符号中获取至少两组导频信息；Obtaining at least two sets of pilot information from a training sequence or a data symbol;
    根据所述导频信息，采用如下公式(1)，获得载波频率偏移值CFO(est)：According to the pilot information, the carrier frequency offset value CFO(est) is obtained by using the following formula (1):
    Figure PCTCN2014090876-appb-100001
    Figure PCTCN2014090876-appb-100001
    其中，pilot1,n为第一组导频信息；pilot2,n为第二组导频信息；TimeDist为两组导频信息之间的时间间隔；n为正整数。Wherein, pilot 1, n is the first set of pilot information; pilot 2, n is the second set of pilot information; TimeDist is the time interval between the two sets of pilot information; n is a positive integer.
  3. 根据权利要求2所述的方法，其特征在于，所述从训练序列或数据符号中获取至少两组导频信息，包括：The method according to claim 2, wherein the obtaining at least two sets of pilot information from the training sequence or the data symbol comprises:
    从第一训练序列和第二训练序列中分别获取一组导频信息；Obtaining a set of pilot information from the first training sequence and the second training sequence respectively;
    或者，从第一训练序列中获取一组导频信息，从第一数据符号中获取另一组导频信息；Or acquiring a set of pilot information from the first training sequence, and acquiring another set of pilot information from the first data symbol;
    或者，从第一数据符号和第二数据符号中分别获取两组导频信息。Alternatively, two sets of pilot information are respectively obtained from the first data symbol and the second data symbol.
  4. 根据权利要求1～3任一项所述的方法，其特征在于，所述根据所述载波频率偏移值，确定所述用户设备对应的载波间干扰ICI消除滤波器系数，包括：The method according to any one of claims 1 to 3, wherein the determining, according to the carrier frequency offset value, the inter-carrier interference ICI cancellation filter coefficient corresponding to the user equipment, including:
    根据所述载波频率偏移值和所述用户设备进行快速傅利叶变换FFT变换时所使用的FFT点数，计算所述用户设备对应的ICI消除滤波器系数；Calculating, according to the carrier frequency offset value and the number of FFT points used by the user equipment to perform fast Fourier transform FFT transform, calculating an ICI cancellation filter coefficient corresponding to the user equipment;
    或者， Or,
    根据所述载波频率偏移值和所述用户设备进行FFT变换时所使用的FFT点数，从预先存储的ICI消除滤波器系数中选择所述用户设备对应的ICI消除滤波器系数。And selecting an ICI cancellation filter coefficient corresponding to the user equipment from the pre-stored ICI cancellation filter coefficients according to the carrier frequency offset value and the number of FFT points used by the user equipment for performing FFT transformation.
  5. 根据权利要求4所述的方法，其特征在于，根据所述载波频率偏移值和所述用户设备进行FFT变换时所使用的FFT点数，计算所述用户设备对应的ICI消除滤波器系数，包括：The method according to claim 4, wherein the ICI cancellation filter coefficients corresponding to the user equipment are calculated according to the carrier frequency offset value and the number of FFT points used by the user equipment for performing FFT transformation, including :
    根据所述载波频率偏移值和所述用户设备进行FFT变换时所使用的FFT点数，采用如下公式(2)，计算所述用户设备对应的ICI消除滤波器系数WFilterTap：Calculating an ICI cancellation filter coefficient W FilterTap corresponding to the user equipment by using the following formula (2) according to the carrier frequency offset value and the number of FFT points used by the user equipment for performing FFT transformation:
    Figure PCTCN2014090876-appb-100002
    Figure PCTCN2014090876-appb-100002
    其中，N为FFT点数、Ntap为滤波器抽头系数；ω＝2π×CFO(est)，CFO(est)为载波频率偏移值。Where N is the number of FFT points, N tap is the filter tap coefficient; ω=2π×CFO(est), and CFO(est) is the carrier frequency offset value.
  6. 根据权利要求4所述的方法，其特征在于，根据所述载波频率偏移值和所述用户设备进行FFT变换时所使用的FFT点数，从预先存储的ICI消除滤波器系数中选择所述用户设备对应的ICI消除滤波器系数，包括：The method according to claim 4, wherein the user is selected from pre-stored ICI cancellation filter coefficients according to the carrier frequency offset value and the number of FFT points used by the user equipment for performing FFT transformation. The ICI cancellation filter coefficients for the device, including:
    根据所述载波频率偏移值、所述用户设备进行FFT变换时所使用的FFT点数和预设的滤波器抽头系数，采用FFT点数匹配、滤波器抽头系数匹配及载波频率偏移值距离最近原则，从预先存储的ICI消除滤波器系数中选择所述用户设备对应的ICI消除滤波器系数。According to the carrier frequency offset value, the number of FFT points used by the user equipment for performing FFT transformation, and the preset filter tap coefficient, the FFT point matching, the filter tap coefficient matching, and the carrier frequency offset value distance nearest principle are adopted. And selecting an ICI cancellation filter coefficient corresponding to the user equipment from the pre-stored ICI cancellation filter coefficients.
  7. 一种正交频分多址OFDMA***中减小子载波间干扰的装置，所述装置为访问节点AP或基站，其特征在于，包括：An apparatus for reducing inter-subcarrier interference in an orthogonal frequency division multiple access OFDMA system, where the apparatus is a visited node AP or a base station, and the method includes:
    估计模块，用于根据用户设备所占用的子载波内的导频符号，估计所述用户设备的载波频率偏移值；An estimation module, configured to estimate a carrier frequency offset value of the user equipment according to a pilot symbol in a subcarrier occupied by the user equipment;
    确定模块，用于根据所述载波频率偏移值，确定所述用户设备对应的载波间干扰ICI消除滤波器系数；a determining module, configured to determine, according to the carrier frequency offset value, an inter-carrier interference ICI cancellation filter coefficient corresponding to the user equipment;
    滤波模块，用于通过所述ICI消除滤波器系数，对所述用户设备的频域数据进行滤波处理。And a filtering module, configured to perform filtering processing on the frequency domain data of the user equipment by using the ICI to eliminate filter coefficients.
  8. 根据权利要求7所述的装置，其特征在于，所述估计模块，具体用于：The device according to claim 7, wherein the estimating module is specifically configured to:
    从训练序列或数据符号中获取至少两组导频信息； Obtaining at least two sets of pilot information from a training sequence or a data symbol;
    根据所述导频信息，采用如下公式(1)，获得载波频率偏移值CFO(est)：According to the pilot information, the carrier frequency offset value CFO(est) is obtained by using the following formula (1):
    Figure PCTCN2014090876-appb-100003
    Figure PCTCN2014090876-appb-100003
    其中，pilot1,n为第一组导频信息；pilot2,n为第二组导频信息；TimeDist为两组导频信息之间的时间间隔；n为正整数。Wherein, pilot 1, n is the first set of pilot information; pilot 2, n is the second set of pilot information; TimeDist is the time interval between the two sets of pilot information; n is a positive integer.
  9. 根据权利要求8所述的装置，其特征在于，所述估计模块，具体用于：The device according to claim 8, wherein the estimating module is specifically configured to:
    从第一训练序列和第二训练序列中分别获取一组导频信息；Obtaining a set of pilot information from the first training sequence and the second training sequence respectively;
    或者，从第一训练序列中获取一组导频信息，从第一数据符号中获取另一组导频信息；Or acquiring a set of pilot information from the first training sequence, and acquiring another set of pilot information from the first data symbol;
    或者，从第一数据符号和第二数据符号中分别获取两组导频信息。Alternatively, two sets of pilot information are respectively obtained from the first data symbol and the second data symbol.
  10. 根据权利要求7～9任一项所述的装置，其特征在于，所述确定模块，具体用于：The device according to any one of claims 7 to 9, wherein the determining module is specifically configured to:
    根据所述载波频率偏移值和所述用户设备进行快速傅利叶变换FFT变换时所使用的FFT点数，计算所述用户设备对应的ICI消除滤波器系数；Calculating, according to the carrier frequency offset value and the number of FFT points used by the user equipment to perform fast Fourier transform FFT transform, calculating an ICI cancellation filter coefficient corresponding to the user equipment;
    或者，or,
    根据所述载波频率偏移值和所述用户设备进行FFT变换时所使用的FFT点数，从预先存储的ICI消除滤波器系数中选择所述用户设备对应的ICI消除滤波器系数。And selecting an ICI cancellation filter coefficient corresponding to the user equipment from the pre-stored ICI cancellation filter coefficients according to the carrier frequency offset value and the number of FFT points used by the user equipment for performing FFT transformation.
  11. 根据权利要求10所述的装置，其特征在于，所述确定模块，具体用于：The device according to claim 10, wherein the determining module is specifically configured to:
    根据所述载波频率偏移值和所述用户设备进行FFT变换时所使用的FFT点数，采用如下公式(2)，计算所述用户设备对应的ICI消除滤波器系数WFilterTap：Calculating an ICI cancellation filter coefficient W FilterTap corresponding to the user equipment by using the following formula (2) according to the carrier frequency offset value and the number of FFT points used by the user equipment for performing FFT transformation:
    Figure PCTCN2014090876-appb-100004
    Figure PCTCN2014090876-appb-100004
    其中，N为FFT点数、Ntap为滤波器抽头系数；ω＝2π×CFO(est)，CFO(est)为载波频率偏移值。Where N is the number of FFT points, N tap is the filter tap coefficient; ω=2π×CFO(est), and CFO(est) is the carrier frequency offset value.
  12. 根据权利要求10所述的装置，其特征在于，所述确定模块，具体用于： The device according to claim 10, wherein the determining module is specifically configured to:
    根据所述载波频率偏移值、所述用户设备进行FFT变换时所使用的FFT点数和预设的滤波器抽头系数，采用FFT点数匹配、滤波器抽头系数匹配及载波频率偏移值距离最近原则，从预先存储的ICI消除滤波器系数中选择所述用户设备对应的ICI消除滤波器系数。 According to the carrier frequency offset value, the number of FFT points used by the user equipment for performing FFT transformation, and the preset filter tap coefficient, the FFT point matching, the filter tap coefficient matching, and the carrier frequency offset value distance nearest principle are adopted. And selecting an ICI cancellation filter coefficient corresponding to the user equipment from the pre-stored ICI cancellation filter coefficients.
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