CN104683284B - The OFDM/OFDMA symbol cyclic shift equalization methods of cyclic prefix are not needed - Google Patents
The OFDM/OFDMA symbol cyclic shift equalization methods of cyclic prefix are not needed Download PDFInfo
- Publication number
- CN104683284B CN104683284B CN201510141031.3A CN201510141031A CN104683284B CN 104683284 B CN104683284 B CN 104683284B CN 201510141031 A CN201510141031 A CN 201510141031A CN 104683284 B CN104683284 B CN 104683284B
- Authority
- CN
- China
- Prior art keywords
- sampling points
- path
- sampling
- ofdm
- vector
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 238000000034 method Methods 0.000 title claims abstract description 30
- 125000004122 cyclic group Chemical group 0.000 title claims abstract description 22
- 238000011084 recovery Methods 0.000 claims abstract description 14
- 239000013256 coordination polymer Substances 0.000 claims abstract 8
- 238000005070 sampling Methods 0.000 claims description 97
- 239000013598 vector Substances 0.000 claims description 49
- 238000006243 chemical reaction Methods 0.000 claims description 23
- 238000001914 filtration Methods 0.000 claims description 11
- 230000004044 response Effects 0.000 claims description 10
- 238000001228 spectrum Methods 0.000 abstract description 5
- 239000002699 waste material Substances 0.000 abstract description 5
- 238000004891 communication Methods 0.000 abstract description 2
- 238000005516 engineering process Methods 0.000 abstract 1
- 238000010586 diagram Methods 0.000 description 5
- 230000008901 benefit Effects 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 2
- 238000005562 fading Methods 0.000 description 2
- 125000004432 carbon atom Chemical group C* 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 238000005065 mining Methods 0.000 description 1
- 238000000638 solvent extraction Methods 0.000 description 1
- 230000003595 spectral effect Effects 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 230000036962 time dependent Effects 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- 238000009827 uniform distribution Methods 0.000 description 1
Landscapes
- Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
Abstract
The OFDM/OFDMA symbol cyclic shift equalization methods of cyclic prefix are not needed, belong to wireless communication technology field.In order to solve the problems, such as it is existing in order to overcome ISI introduce CP and waste frequency spectrum resource and power consumption.Methods described includes：The transmitting terminal of OFDM/OFDMA systems is sending data block biWhen, the default link for adding CP, send M symbol；And the receiving terminal of OFDM/OFDMA systems is receiving data block biWhen, M sampled point is obtained, utilizes the preceding L 1 and data block b of the sampled point of receptioni‑1Make decisions the vectorial rear L 1 that feedback equalization operation obtains to make the difference, obtained after making the difference and carry out CP recovery operations with sampled point residue M L+1 items, be finally filtered output.ISI phenomenons caused by the feedback equalization operation that the present invention uses has effectively eliminated multipath transmisstion, avoid waste caused by CP frequency spectrum resources and power consumption again.
Description
Technical Field
The invention belongs to the technical field of wireless communication, and particularly relates to an OFDM/OFDMA symbol cyclic shift equalization method without cyclic prefix.
Background
Because the OFDM/OFDMA technique has the advantages of higher spectral efficiency, good anti-frequency selection capability, easy digital implementation, etc., it has become a modulation technique, a frequency multiplexing technique, and a multiple access technique that are currently highly appreciated. However, when the OFDM/OFDMA system operates in a multipath environment, Inter-symbol interference (ISI) may be caused by frequency selective fading. To overcome this problem, it is conventional to add Cyclic Prefix (CP) between OFDM/OFDMA symbols, which has the advantage that the OFDM/OFDMA symbols can convert the linear shift caused by multipath propagation into Cyclic shift at the receiving end by means of CP. After the symbols are recovered by FFT/IFFT, the effect of frequency selective fading can be eliminated by using a one-tap equalizer.
From an information perspective, the CP does not contain any information and is redundant. It is wasteful in both spectrum resources and power consumption and its length is limited by the physical environment (greater than or equal to the maximum multipath delay). As the transmission rate increases, OFDM/OFDMA symbols become shorter and shorter, and the relative length of the CP becomes longer and longer, resulting in greater waste. Therefore, to further develop OFDM/OFDMA, the CP problem may become one of the biggest obstacles.
Disclosure of Invention
The invention aims to solve the problem that the existing method for overcoming the defect that the ISI introduces the CP to waste spectrum resources and power consumption, and provides an OFDM/OFDMA symbol cyclic shift equalization method without a cyclic prefix.
The cyclic shift equalization method of OFDM/OFDMA symbols without cyclic prefix of the invention,
the method comprises the following steps:
data block b of I data blocks to be transmitted of each user at transmitting end of OFDM/OFDMA systemiThe sending method comprises the following steps:
step A1: a block b of serial data to be transmittediPerforming serial-to-parallel conversion to obtain data block biConverted M symbols bi,mWherein M is 0,1, … M-1; the period of the code element is Tb；biDenotes the ith data block, I ═ 2, … I;
step A2: m symbols to be obtainedPerforming IFFT conversion, parallel-serial conversion, digital-to-analog conversion and carrier modulation in sequence, and transmitting data after carrier modulation through an antenna;
data block b of I data blocks to be received by receiving end of OFDM/OFDMA system for each useriThe receiving method comprises the following steps:
step B1: after carrier demodulation of received signal, T is usedbSampling is carried out for a sampling period to obtain M sampling points;
step B2: performing serial-parallel conversion on the obtained M sampling points to obtain M paths of parallel sampling points;
step B3: the first L-1 sampling points in the M parallel sampling points are respectively connected with the received data block bi-1The L-1 item output by the time decision feedback equalization operation is subjected to subtraction, and CP recovery operation is carried out on the sampling points of the L-1 path obtained after the subtraction and the sampling points of the last M-L +1 path in the sampling points of the M paths in parallel;
step B4: performing FFT (fast Fourier transform) and parallel-serial conversion on the M sampling points obtained by the CP recovery operation in sequence to obtain a path of serial data, and performing filtering judgment on the obtained path of serial data to output;
step B5: and (3) performing decision feedback equalization operation on the data output by the filtering decision:
and sequentially performing serial-parallel conversion and IFFT (inverse fast Fourier transform) on data output by filtering judgment to obtain M discrete values, performing convolution operation on the obtained M discrete values and unit impulse response of a channel, and obtaining a vector with the length of M + L-1 after the convolution operation, wherein the vector of the last L-1 item is an L-1 item output by judgment feedback equalization operation, and L is the length of the channel.
In step B3, the method for performing CP recovery operation on the L-1 way sampling point obtained after the difference and the last M-L +1 way sampling point in the M ways of parallel sampling points includes:
step B31: when the L-1 sampling points obtained after the difference is processed, the 0 th sampling point r in the L-1 sampling points obtained after the difference is utilizedi(0) Sum channel impulse responseMultiplying to obtain the vector of the 0 th path:and will beInputting to a memory for storage; 0, … L-1;
wherein,represents the 0 th sampling point, rho, of the path l when the ith data block is transmittedlDenotes the channel gain, p, of the l-th path0Denotes the channel gain of path 0, j being the imaginary unit, i.e. j2＝-1；φlIndicates the phase error of the l-th path, phi0Represents the phase error of path 0;
step B32: according to the n (n is more than or equal to 1 and less than or equal to L-2) sampling points r in the L-1 sampling points obtained after the difference is madei(n) and the obtained vectors, and sequentially obtaining the vectors corresponding to the rest L-2 sampling points by using a formula IAnd apply the vectorInputting to a memory for storage;
a first formula;
wherein,representing the nth sampling point passing through the path l when the ith data block is transmitted;
step B33: when L-1 is more than or equal to n and less than or equal to M-1, namely the last M-L +1 sampling points in the M paths of parallel sampling points are processed, the vector corresponding to the condition that L-1 is more than or equal to n and less than or equal to M-1 is obtained by using the nth sampling point and combining the formula IIWill vectorAn input memory store;
a second formula;
wherein,representing the nth sampling point passing through the path l when the ith data block is transmitted;
step B34: according to M vectors and sampling points r stored in the memoryi(n), adding to obtain:
a formula III;
step B35: obtaining a vector according to the formula threeThe vectorM sampling points obtained for the CP recovery operation.
The invention has the advantages that the invention does not introduce the link of adding the cyclic prefix CP between symbols in the process of processing the OFDM/OFDMA signal by the sending end, namely: the frame structure of the OFDM/OFDMA signal does not contain a cyclic prefix; the feedback equalization operation adopted by the receiving end of the invention effectively eliminates the ISI phenomenon caused by multipath propagation. Therefore, the invention eliminates the ISI phenomenon and avoids the waste caused by CP frequency spectrum resources and power consumption.
Drawings
Fig. 1 is a schematic diagram of a transmitting end of SCSE-OFDM in a first embodiment.
Fig. 2 is a diagram illustrating a comparison between the frame structure of SCSE-OFDM/OFDMA and the conventional OFDM/OFDMA in the first embodiment.
Fig. 3 is a schematic diagram of a receiving end of SCSE-OFDM according to a first embodiment.
Fig. 4 is a schematic diagram illustrating a CP recovery operation in the first embodiment.
Fig. 5 is a schematic diagram of a transmitting end of an OFDMA system.
Detailed Description
The first embodiment is as follows: the present embodiment is described with reference to fig. 1, fig. 2 and fig. 3, and provides a method for cyclic shift equalization of an OFDM symbol without a cyclic prefix, where the method includes:
the OFDM system is a subsystem of the OFDA system, and as shown in fig. 1, at a transmitting end of SCSE-OFDM, for each user, a data block b of I data blocks to be transmittediThe sending method comprises the following steps:
step A1: a block b of serial data to be transmittediPerforming serial-to-parallel conversion to obtain data block biConverted M symbols bi,mWherein M is 0,1, … M-1; the period of the code element is Tb；biDenotes the ith data block, I ═ 2, … I;
step A2: m symbols to be obtainedPerforming IFFT conversion, parallel-serial conversion, digital-to-analog conversion and carrier modulation in sequence, and transmitting data after carrier modulation through an antenna; bi,mAn mth symbol for an ith data block;
the main difference between the signal processing flow of the sending end of the embodiment and the traditional OFDM is that a link of adding the CP is default.
Assuming that the user BPSK maps the data before transmission,
is thatThe result after the IFFT transformation of M points:
according toThe frame structure of SCSE-OFDM/OFDMA can be obtained as shown in fig. 2. In fig. 2, the frame structure of SCSE-OFDM/OFDMA is compared with the conventional OFDM/OFDMA. Where the maximum multipath delay is assumed to be L-1 symbols.
After D/A conversion, s is obtainedi(t) si (t). Here, si(t) is a baseband signal, and then the signal is subjected to carrier modulation to obtain:
finally, the radio frequency signal is transmittedAnd transmitted out through the antenna.
A static multipath channel model is introduced here, and assuming that the channel state does not change within one symbol time, the unit impulse response of the channel is,
in the above formula, ρlIs the channel gain, obeying the rayleigh distribution; phi is alIs the phase error of the multipath channel, obeying [0,2 π]Uniform distribution of the components; tau islIs a multipath time delay with a maximum multipath time delay of tauL-1Let the number of distinguishable diameters be L; suppose the sampling interval is TbIts discrete form is a vector of L:
in the above formula, the first and second carbon atoms are,let l be τl/Tb. After sampling, the multipath delay of the channel is actually quantized by the sampling interval, which is the sampling interval. Then the receiver exhibits a multipath delay that is an integer multiple of the sampling interval. It is clear that the unit impulse response of a channel is represented by a vector of length L, which, in this sense, is equal in value to the number of paths of the multipath channel.
As shown in fig. 3, at the receiving end of the SCSE-OFDM system, for each user, a data block b of I data blocks to be receivediThe receiving method comprises the following steps:
step B1: after carrier demodulation of received signal, T is usedbSampling for a sampling period to obtain a set of vectors:
the vector consists of M sampling points;
step B2: performing serial-parallel conversion on the obtained M sampling points to obtain M paths of parallel sampling points;
step B3: dividing the M parallel sampling points into two parts: the number of the first part of sampling points is equal to the number of the sampling points contained in the maximum multipath delay, obviously, the number of the first part of sampling points is taken as L-1 through the definition of the variables; in the vector of M sampling points, the rest M-L +1 sampling points are the second part; due to the influence of multipath channel, for data block biWhen sampling, the first L-1 sampling points may be received by the data block bi-1So as to pair biWhen the treatment is carried out, the treatment can be divided into two parts:
first, M-way parallel samplingThe first L-1 sampling points in the points are respectively connected with the received data block bi-1The process of making a difference between the L-1 items output by the time-dependent decision feedback equalization operation comprises the following steps:
data block bi-1Performing IFFT processing of M points to output M discrete values
Performing convolution operation on the obtained M discrete values and the impulse response of the channel to obtain a group of vectors with the length of M + L-1:
wherein,in order to be the impulse response of the channel,representing a convolution operation;
fromAfter extraction of L-1, i.eAndmaking a difference to obtain
The L-1 sampling points obtained after the difference is madeMining in parallel with M-wayRear M-L +1 sampling points r in sampling pointsi(n) performing a CP recovery operation;
step B4: performing FFT (fast Fourier transform) and parallel-serial conversion on the M sampling points obtained by the CP recovery operation in sequence to obtain a path of serial data, and performing filtering judgment on the obtained path of serial data to output;
the filtering in this step is single-tap filtering, eliminating the influence of phase inversion.
Step B5: and (3) performing decision feedback equalization operation on the data output by the filtering decision:
and sequentially performing serial-parallel conversion and IFFT (inverse fast Fourier transform) on data output by filtering judgment to obtain M discrete values, performing convolution operation on the obtained M discrete values and unit impulse response of a channel, and obtaining a vector with the length of M + L-1 after the convolution operation, wherein the vector of the last L-1 item is an L-1 item output by judgment feedback equalization operation, and L is the length of the channel.
The second embodiment is as follows: the present embodiment is described with reference to fig. 4, which is a further limitation of the OFDM symbol cyclic shift equalization method without cyclic prefix described in the first embodiment,
in step B3, the method for performing CP recovery operation on the L-1 way sampling point obtained after the difference and the last M-L +1 way sampling point in the M ways of parallel sampling points includes:
step B31: when the L-1 sampling points obtained after the difference is processed, the 0 th sampling point r in the L-1 sampling points obtained after the difference is utilizedi(0) Sum channel impulse responseMultiplying to obtain the vector of the 0 th path:and will beInputting to a memory for storage; 0, … L-1;
wherein,represents the 0 th sampling point, rho, of the path l when the ith data block is transmittedlDenotes the channel gain, p, of the l-th path0Denotes the channel gain of path 0, j being the imaginary unit, i.e. j2＝-1；φlIndicates the phase error of the l-th path, phi0Represents the phase error of path 0;
step B32:
according to the n (n is more than or equal to 1 and less than or equal to L-2) sampling points r in the L-1 sampling points obtained after the difference is madei(n) and the obtained vectors, and sequentially obtaining the vectors corresponding to the rest L-2 sampling points by using a formula IAnd apply the vectorInputting to a memory for storage; obtaining a specific process of formula one:
according to the vector of the 0 th path and the 1 st path sampling point ri(1) And the impulse response of the channel to obtain the vector of the 1 st path
According to the vector of the 0 th path, the vector of the 1 st path and the 2 nd sampling point ri(2) And impulse response of the channel, obtaining the vector of the 2 nd path:
according to the vector of the 0 th path, the vector of the 1 st path, the vector of the 2 nd path and the 3 rd sampling point ri(3) And impulse response of the channel, obtaining the vector of the 2 nd path:
and the general term of the vector of the nth (n is more than or equal to 1 and less than or equal to L-2) way is obtained by analogy:
a first formula;
wherein,representing the nth sampling point passing through the path l when the ith data block is transmitted;
step B33: when L-1 is more than or equal to n and less than or equal to M-1, namely the last M-L +1 sampling points in the M paths of parallel sampling points are processed, the vector corresponding to the condition that L-1 is more than or equal to n and less than or equal to M-1 is obtained by using the nth sampling point and combining the formula IIWill vectorAn input memory store;
a second formula;
wherein,representing the nth sampling point passing through the path l when the ith data block is transmitted;
step B34: according to the storageM vectors and sample points r stored in memoryi(n), adding to obtain:
a formula III;
step B35: obtaining a vector according to the formula threeThe vectorM sampling points obtained for the CP recovery operation.
As can be seen from fig. 5, OFDM is a sub-system of OFDMA, so the present invention is equally applicable to OFDMA systems. When the invention is applied to an OFDM system, the system is called SCSE-OFDM; when the present invention is used in an OFDMA system, it is referred to as a SCSE-OFDMA system; although the present invention does not relate to the flow of user resource block partitioning, it is not meant that the present invention does not cover SCSE-OFDMA.
Claims (1)
1. A method for cyclic shift equalization of OFDM/OFDMA symbols without cyclic prefix, the method comprising:
data block b of I data blocks to be transmitted of each user at transmitting end of OFDM/OFDMA systemiThe sending method comprises the following steps:
step A1: a block b of serial data to be transmittediPerforming serial-to-parallel conversion to obtain data block biConverted M symbols bi,mWherein M is 0,1, … M-1; the period of the code element is Tb；biWhich represents the ith data block of the data,i＝2,…I；
step A2: m symbols to be obtainedPerforming IFFT conversion, parallel-serial conversion, digital-to-analog conversion and carrier modulation in sequence, and transmitting data after carrier modulation through an antenna;
data block b of I data blocks to be received by receiving end of OFDM/OFDMA system for each useriThe receiving method comprises the following steps:
step B1: after carrier demodulation of received signal, T is usedbSampling is carried out for a sampling period to obtain M sampling points;
step B2: performing serial-parallel conversion on the obtained M sampling points to obtain M paths of parallel sampling points;
step B3: the first L-1 sampling points in the M parallel sampling points are respectively connected with the received data block bi-1The L-1 item output by the time decision feedback equalization operation is subjected to subtraction, and CP recovery operation is carried out on the sampling points of the L-1 path obtained after the subtraction and the sampling points of the last M-L +1 path in the sampling points of the M paths in parallel;
step B4: performing FFT (fast Fourier transform) and parallel-serial conversion on the M sampling points obtained by the CP recovery operation in sequence to obtain a path of serial data, and performing filtering judgment on the obtained path of serial data to output;
step B5: and (3) performing decision feedback equalization operation on the data output by the filtering decision:
carrying out serial-to-parallel conversion and IFFT conversion on data output by filtering judgment in sequence to obtain M discrete values, carrying out convolution operation on the obtained M discrete values and unit impulse response of a channel, and obtaining a vector with the length of M + L-1 after the convolution operation, wherein the vector of the last L-1 item is an L-1 item output by judgment feedback equalization operation, and L is the length of the channel;
in step B3, the method for performing CP recovery operation on the L-1 way sampling point obtained after the difference and the last M-L +1 way sampling point in the M ways of parallel sampling points includes:
step B31: when the L-1 sampling points obtained after the difference is processed, the 0 th sampling point r in the L-1 sampling points obtained after the difference is utilizedi(0) Sum channel impulse responseMultiplying to obtain the vector of the 0 th path:and will beInputting to a memory for storage; 0, … L-1;
wherein,represents the 0 th sampling point, rho, of the path l when the ith data block is transmittedlDenotes the channel gain, p, of the l-th path0Denotes the channel gain of path 0, j being the imaginary unit, i.e. j2＝-1；φlIndicates the phase error of the l-th path, phi0Represents the phase error of path 0;
step B32: according to the nth sampling point r in the L-1 sampling points obtained after the difference is madei(n) and the obtained vectors, n is more than or equal to 1 and less than or equal to L-2, and sequentially obtaining the vectors corresponding to the rest L-2 sampling points by using a formula IAnd apply the vectorInputting to a memory for storage;
wherein,representing the n-th sampling point of the path l when the ith data block is transmitted;
step B33: when L-1 is not less than n and not more than M-1, namely the last M-L +1 sampling points in the M paths of parallel sampling points are processed, the vector corresponding to the condition that L-1 is not less than n and not more than M-1 is obtained by using the nth sampling point and combining the formula IIWill vectorAn input memory store;
step B34: according to M vectors and sampling points r stored in the memoryi(n), adding to obtain:
step B35: obtaining a vector according to the formula threeThe vectorM sampling points obtained for the CP recovery operation.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510141031.3A CN104683284B (en) | 2015-03-27 | 2015-03-27 | The OFDM/OFDMA symbol cyclic shift equalization methods of cyclic prefix are not needed |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510141031.3A CN104683284B (en) | 2015-03-27 | 2015-03-27 | The OFDM/OFDMA symbol cyclic shift equalization methods of cyclic prefix are not needed |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN104683284A CN104683284A (en) | 2015-06-03 |
| CN104683284B true CN104683284B (en) | 2018-03-30 |
Family
ID=53317895
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201510141031.3A Expired - Fee Related CN104683284B (en) | 2015-03-27 | 2015-03-27 | The OFDM/OFDMA symbol cyclic shift equalization methods of cyclic prefix are not needed |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN104683284B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105245476B (en) * | 2015-08-27 | 2018-03-30 | 哈尔滨工业大学 | Suitable for the efficient symbol cyclic shift equalization methods of non-cycle prefix OFDM/OFDMA systems |
| CN105282084A (en) * | 2015-11-20 | 2016-01-27 | 哈尔滨工业大学 | Storage feedback equalization method based on SCSE-OFDM/OFDMA system |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101867553A (en) * | 2010-06-21 | 2010-10-20 | 重庆邮电大学 | LTE system using time domain precoder and precoding method thereof |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8484272B2 (en) * | 2004-08-20 | 2013-07-09 | Qualcomm Incorporated | Unified pulse shaping for multi-carrier and single-carrier waveforms |
-
2015
- 2015-03-27 CN CN201510141031.3A patent/CN104683284B/en not_active Expired - Fee Related
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101867553A (en) * | 2010-06-21 | 2010-10-20 | 重庆邮电大学 | LTE system using time domain precoder and precoding method thereof |
Non-Patent Citations (4)
| Title |
|---|
| Efficient Cyclic Prefix Reconstruction for Coded OFDM Systems;Cheol-Jin Park，Gi-Hong Im;《IEEE COMMUNICATIONS LETTERS》;20040531;第8卷(第5期);第274-276页 * |
| Elimination of Cyclic Prefix of OFDM systems using filter bank based multicarrier systems;Krishna Arya, Dr. C. Vijaykumar;《TENCON 2008 - 2008 IEEE Region 10 Conference》;20090127;第1-5页 * |
| Low-Complexity Turbo Equalization for MIMO-OFDM System without Cyclic Prefix;Zhe Chen,Chang Yongyu，Dacheng Yang;《Personal, Indoor and Mobile Radio Communications, 2009 IEEE 20th International Symposium on》;20100415;第310-314 * |
| 一种无循环前缀的新型短波MB-OFDM系统;阚春荣，徐天顺，刘颖，任国春;《解放军理工大学学报(自然科学版)》;20070831;第8卷(第4期);第315-319页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN104683284A (en) | 2015-06-03 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Ma et al. | A low complexity MMSE for OFDM systems over frequency-selective fading channels | |
| CN101409694B (en) | Method and system for implementing single carrier frequency domain equilibrium | |
| CN101127532B (en) | Restraint method and system for mutual interference of orthogonal frequency division multiplexing communication carrier frequency | |
| EP1863243A1 (en) | Wireless communication apparatus | |
| CN109309542B (en) | Orthogonal signal division multiplexing underwater acoustic communication method based on time domain oversampling | |
| JP2012520587A (en) | OFDM receiving system and method in the presence of Doppler effect based on time domain windowing | |
| CN102045285B (en) | Channel estimation method and device and communication system | |
| CN109088836B (en) | Data block construction method for single carrier frequency domain equalization SOQPSK-TG signal | |
| CN104683284B (en) | The OFDM/OFDMA symbol cyclic shift equalization methods of cyclic prefix are not needed | |
| CN103348622A (en) | Signal processing method and apparatus in microwave communication system | |
| CN104301282B (en) | A kind of ICI Adaptive Suppression methods of ultrahigh speed OFDM in Mobile | |
| Dai et al. | Time domain synchronous OFDM based on simultaneous multi-channel reconstruction | |
| WO2017167386A1 (en) | A transmitter for transmitting and a receiver for receiving a plurality of multicarrier modulation signals | |
| Kwon et al. | Cross-antenna interference cancellation and channel estimation for MISO-FBMC/QAM-based eMBMS | |
| WO2016092323A1 (en) | Estimating data symbols from a filter bank multicarrier (fbmc) signal | |
| CN105991489A (en) | Method for realizing channel equalization by using frequency-domain oversampling | |
| CN105245476B (en) | Suitable for the efficient symbol cyclic shift equalization methods of non-cycle prefix OFDM/OFDMA systems | |
| Fang et al. | Subspace-based blind channel estimation by separating real and imaginary symbols for cyclic-prefixed single-carrier systems | |
| Babulkar | A Comprehensive Review on Channel Estimation Techniques in MIMO-OFDM | |
| US9667455B1 (en) | System and method for large dimension equalization using small dimension equalizers and bypassed equalizers | |
| Chan et al. | A precoding scheme for eliminating data identification problem in single carrier system using data-dependent superimposed training | |
| Kim et al. | A bandwidth efficient OFDM transmission scheme | |
| WO2016031496A1 (en) | Transmission apparatus, transmission method, reception apparatus, and reception method | |
| WO2016166822A1 (en) | Transmission device, reception device, and communication system | |
| CN101123598A (en) | Communication device and its method based on DFDMA and LFDMA |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20180330 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |