CN102437995A - Iterative carrier synchronizing method and system based on code-by-code iterative detection - Google Patents
Iterative carrier synchronizing method and system based on code-by-code iterative detection Download PDFInfo
- Publication number
- CN102437995A CN102437995A CN2012100214209A CN201210021420A CN102437995A CN 102437995 A CN102437995 A CN 102437995A CN 2012100214209 A CN2012100214209 A CN 2012100214209A CN 201210021420 A CN201210021420 A CN 201210021420A CN 102437995 A CN102437995 A CN 102437995A
- Authority
- CN
- China
- Prior art keywords
- frequency offset
- idma
- iterative detection
- offset estimating
- ofdm
- 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.)
- Pending
Links
Images
Abstract
The invention discloses an iterative carrier synchronizing method based on code-by-code iterative detection. The method comprises the following steps of: reconstructing external information generated during the code-by-code iterative detection of interleave-division multiple-access (IDMA) to acquire a reconstructed signal; performing frequency offset estimation according to a received signal during the current iterative detection of the IDMA and the reconstructed signal acquired during the last iterative detection to acquire a current frequency offset estimated value; and compensating a frequency offset generated during the current iterative detection by using the current frequency offset estimated value. Correspondingly, the invention discloses an orthogonal frequency division multiplexing (OFDM)-IDMA carrier synchronizing system based on the code-by-code iterative detection. By combining a multi-user detection mechanism of the OFDM-IDMA system with a frequency offset signal processing method technology, the estimation and the compensation is performed cyclically through an iteration mode, so that the frequency offset estimation precision is improved and the performance of a link of the system is optimized; therefore, the performance of the system subjected to the carrier frequency offset interference is made to gradually approximate to the performance of the system free of the frequency offset, and the carrier synchronization of the system is realized.
Description
Technical field
The present invention relates to the communications field, relate in particular to a kind of iteration carrier synchronization method and system based on the OFDM-IDMA that pursues the chip iterative detection.
Background technology
OFDM (OFDM; Orthogonal Frequency Division Multiplexing) technology is one of key technology of future broadband wireless communication systems; And interlacing multi-address (IDMA; Interleave-division multiple-access) caused people's extensive concern as a kind of novel multiple access technique, OFDM combines with the IDMA technology, promptly constitutes OFDM-IDMA.The OFDM-IDMA scheme is to have replaced the CDMA technology in the OFDM-CDMA scheme with the IDMA technology; OFDM-IDMA has inherited the technical advantage of OFDM and IDMA technology; Wherein, OFDM has high spectrum efficiency and anti-intersymbol interference (ISI, internsymbol interference); IDMA is to use rate code and interleaver to distinguish user's multiple access technique; IDMA has inherited characteristics such as decline of CDMA anti-multipath and resisting multi-user interference, and the complexity of the Multiuser Detection of IDMA is lower than CDMA, and the availability of frequency spectrum is higher than CDMA.Therefore OFDM-IDMA more has superiority than OFDM-CDMA; It is one of future mobile communications important technology scheme; The OFDM-IDMA system architecture diagram can comprise referring to Fig. 1: OFDM modulator 101, ofdm demodulator 102 and IDMA receiver, and said IDMA receiver is a multi-user detector 103; Behind the signal interpolation additive white Gaussian noise of OFDM modulator 101 outputs, be input to ofdm demodulator 102, multi-user detector 103 receives ofdm demodulators 102 output signals.
Yet OFDM-IDMA has inherited the sensitiveness characteristic of OFDM to carrier wave frequency deviation inevitably, makes OFDM-IDMA obtain will to stand the influence of carrier wave frequency deviation inevitably under the appreciable technical advantage.Carrier wave frequency deviation is that the non-linear or Doppler frequency shift by the incomplete coupling of transmitting-receiving two-end local oscillator, wireless channel causes.The existence of carrier wave frequency deviation can reduce signal amplitude, produce phase distortion and thereby the orthogonality destroyed between the OFDM subcarrier causes inter-carrier interference (ICI; Inter-carrier interference); Cause the loss of signal to noise ratio; And systematic function descends, therefore to the analysis of its carrier wave frequency deviation and seek effective carrier wave frequency deviation to overcome method be significant.
Summary of the invention
The purpose of this invention is to provide and a kind ofly solve the carrier wave frequency deviation problem in the OFDM-IDMA communication system, can effectively overcome frequency deviation, improve systematic function based on by the iteration carrier synchronization method and the system of chip iterative detection.
In order to realize the foregoing invention purpose, the invention provides a kind ofly based on by the iteration carrier synchronization method of chip iterative detection, comprising:
IDMA is carried out reconstruct by the external information that produces in the chip iterative detection at every turn, obtain reconstruction signal;
Reconstruction signal according to obtaining in reception signal in the IDMA current iteration testing process and the last iterative detection process carries out frequency offset estimating, obtains current frequency offset estimating value;
Said current frequency offset estimating value is used for the frequency deviation that the current iteration testing process produces is compensated.
Wherein, in first time iterative detection process, the frequency deviation that produces in the iterative detection process first time is compensated with first frequency offset estimating value.
Accordingly, saidly obtain current frequency offset estimating value and specifically comprise:
According to the reconstruction signal that obtains in reception signal in the IDMA current iteration testing process and the last iterative detection process according to formula:
carries out frequency offset estimating; Obtain current frequency offset estimating value; Wherein
is for receiving signal;
for utilizing the signal of external information reconstruct,
is channel frequency response.
Wherein, said first frequency offset estimating value is come out according to the maximal possibility estimation algorithm computation.
Accordingly; It is a kind of based on the OFDM-IDMA carrier synchronization system by the chip iterative detection that the present invention also provides; Comprise: OFDM modulator, ofdm demodulator and IDMA receiver; Said IDMA receiver is a multi-user detector, behind the signal interpolation additive white Gaussian noise of OFDM modulator output, is input to ofdm demodulator, and said system also comprises frequency deviation estimating modules and compensate of frequency deviation module;
Said multi-user detector carries out reconstruct by the external information that produces in the chip iterative detection with IDMA at every turn, obtains reconstruction signal;
Said frequency deviation estimating modules is carried out frequency offset estimating according to the reconstruction signal that obtains in reception signal in the IDMA current iteration testing process and the last iterative detection process, obtains current frequency offset estimating value;
Said compensate of frequency deviation module is used for said current frequency offset estimating value the frequency deviation that the current iteration testing process produces is compensated.
Wherein, said system also comprises: first frequency deviation estimating modules is used to calculate first frequency offset estimating value; Said compensate of frequency deviation module compensates the frequency deviation that produces in the iterative detection process first time with first frequency offset estimating value in first time iterative detection process.
Wherein, said ofdm demodulator further comprises: remove cyclic prefix unit, FFT carrier wave demodulation device and IDFT carrier wave demodulation device.
Wherein, said OFDM modulator further comprises: DFT unit, subcarrier map unit, IFFT carrier modulation unit and add cyclic prefix unit.
Wherein, said multi-user detector further comprises: baseband signal estimator ESE, single user's posterior probability APP decoder despreader and decoder DEC.
Compared with prior art, the present invention has following beneficial effect:
The Multiuser Detection mechanism of OFDM-IDMA system is combined with frequency offset signal processing method technology; To carry out reconstruct by the external information in the chip iterative detection mechanism; And with the signal of reconstruct as carrying out the input signal of frequency offset estimating next time, in the iterative detection process, utilize to receive signal and reconstruction signal carries out frequency offset estimating; Again the frequency deviation of estimating is used for compensate of frequency deviation, correcting frequency offset is to the interference of subscriber signal.Through the mode of iteration, circulation carry out to be estimated and compensation, has improved the precision and the performance of having optimized system link of frequency offset estimating, the performance in the time of can making the systematic function that receives the carrier wave frequency offset interference approach no frequency deviation gradually, the carrier synchronization of realization system.
Description of drawings
In order to be illustrated more clearly in the embodiment of the invention or technical scheme of the prior art; To do to introduce simply to the accompanying drawing of required use in embodiment or the description of the Prior Art below; Obviously, the accompanying drawing in describing below only is some embodiments of the present invention, for those of ordinary skills; Under the prerequisite of not paying creative work property, can also obtain other accompanying drawing according to these accompanying drawings:
Fig. 1 is the OFDM-IDMA system architecture diagram;
Fig. 2 is an OFDM-IDMA carrier synchronization system architecture diagram in the embodiment of the invention;
Fig. 3 is based on the iteration carrier synchronization method flow chart by the chip iterative detection in the embodiment of the invention.
Embodiment
To combine the accompanying drawing in the embodiment of the invention below, the technical scheme in the embodiment of the invention is carried out clear, intactly description, obviously, described embodiment only is the present invention's part embodiment, rather than whole embodiment.Based on the embodiment among the present invention, those of ordinary skills are not making the every other embodiment that is obtained under the creative work prerequisite, all belong to the scope of the present invention's protection.
The present invention is directed to the carrier wave frequency deviation problem that exists in the OFDM-IDMA system; Multiuser Detection mechanism in conjunction with the OFDM-IDMA system; Based on by the Nonlinear Transformation in Frequency Offset Estimation and the frequency bias compensation method of chip iterative detection, this method utilization is by the external information reconstruction signal in the chip iterative detection under identical frequency deviation in proposition, and with the signal of reconstruct with receive the input signal of signal and carry out frequency offset estimating as frequency deviation estimating modules; Carry out the related offset compensation simultaneously; Estimate and the execution of iterative compensation through iteration, improve the precision of frequency offset estimating, thereby obtain more excellent carrier synchronization performance.
At first combine Fig. 2 to introduce OFDM-IDMA carrier synchronization system architecture in the embodiment of the invention; Referring to Fig. 2; In the embodiment of the invention based on by the OFDM-IDMA carrier synchronization system of chip iterative detection; Comprise: OFDM modulator 201, ofdm demodulator 202 and IDMA receiver; Said IDMA receiver is a multi-user detector 203, behind the signal interpolation additive white Gaussian noise of OFDM modulator 201 outputs, is input to ofdm demodulator 202, and embodiment of the invention system also comprises frequency deviation estimating modules 204 and compensate of frequency deviation module 205; Said multi-user detector 203 carries out reconstruct by the external information that produces in the chip iterative detection with IDMA at every turn, obtains reconstruction signal; Said frequency deviation estimating modules according to the reconstruction signal that obtains in reception signal in the IDMA current iteration testing process and the last iterative detection process according to formula:
carries out frequency offset estimating; Obtain current frequency offset estimating value; Wherein
is for receiving signal;
is for utilizing the signal of external information reconstruct; The mechanism of reconstruct is exactly the user data information method for updating of utilizing in the detection of IDMA iteraction multiple users, and
is channel frequency response; Said compensate of frequency deviation module is used for said current frequency offset estimating value the frequency deviation that the current iteration testing process produces is compensated.
Because during first frequency offset estimating; Receive signal and also do not get into iterative processing, do not constitute the frequency offset estimating pilot frequency information, in order not influence whole systematic function; System of the present invention can also comprise: first frequency deviation estimating modules (not shown among Fig. 2); Be used to calculate first frequency offset estimating value, make said compensate of frequency deviation module 205 in first time iterative detection process, the frequency deviation that produces in the iterative detection process first time is compensated with first frequency offset estimating value.First frequency offset estimating can adopt classical maximum likelihood frequency deviation estimating method, and this prescribing method does not have uniqueness certainly, can adjust according to system link, as long as help the system link carrier synchronization processes.Because the embodiment of the invention has been considered first frequency offset estimating, rather than initial frequency deviation is set to 0 simply, helps the performance optimization of the precision and the entire system of Nonlinear Transformation in Frequency Offset Estimation.
In the embodiment of the invention in the OFDM-IDMA system IDMA transmitter main modular comprise: chnnel coding unit, duplication code spectrum-spreading unit, random interleaver, QPSK or BPSK modulator; Ofdm demodulator comprises: remove cyclic prefix unit, FFT carrier wave demodulation device and IDFT carrier wave demodulation device; The OFDM modulator comprises: DFT unit, subcarrier map unit, IFFT carrier modulation unit and add cyclic prefix unit; Multi-user detector comprises: baseband signal estimator ESE, single user's posterior probability APP decoder despreader and decoder DEC.
Introduce in the embodiment of the invention based on iteration carrier synchronization method below in conjunction with Fig. 3 by the chip iterative detection; This method is inter-carrier interference and the multi-user interference that the OFDM-IDMA system is caused to frequency deviation; A kind of method that overcomes frequency offset interference that proposes belongs to the method that a kind of carrier wave frequency deviation iteration estimation combines with iterative compensation.
Referring to Fig. 3, in the embodiment of the invention based on by the iteration carrier synchronization method flow chart of chip iterative detection, said method comprises the steps:
Step S301: in first time iterative detection process; With first frequency offset estimating value the frequency deviation that produces in the iterative detection process first time is compensated; Said first frequency offset estimating value can adopt classical maximum likelihood frequency deviation estimating method to calculate; Certainly this prescribing method does not have uniqueness, can adjust according to system link, as long as help the system link carrier synchronization processes.
Step S302: IDMA is carried out reconstruct by the external information that produces in the chip iterative detection at every turn, obtain reconstruction signal, this step is with the input signal of reconstruction signal as frequency offset estimator, for frequency offset estimating is prepared;
Step S303: since the iterative detection process second time; Reconstruction signal according to obtaining in reception signal in the IDMA current iteration testing process and the last iterative detection process carries out frequency offset estimating; Obtain current frequency offset estimating value; Computing formula is:
; Wherein
is for receiving signal;
is for utilizing the signal of external information reconstruct; The mechanism of reconstruct is exactly the user data information method for updating of utilizing in the detection of IDMA iteraction multiple users, and
is channel frequency response.
Step S304: said current frequency offset estimating value is used for the frequency deviation that the current iteration testing process produces is compensated.
The present invention is based on iteration carrier synchronization method by the chip iterative detection; Be not only applicable to the OFDM-IDMA system; Also can further expand the carrier synchronization processes that applies to the SC-FDMA-IDMA system that SC-FDMA combines with the IDMA technology under the LTE background; One of ordinary skill in the art will appreciate that all or part of flow process that realizes in the foregoing description method, is to instruct relevant hardware to accomplish through computer program.
In the embodiment of the invention, the method and technology that the Multiuser Detection mechanism and the frequency offset signal of OFDM-IDMA system are handled combines.Utilize OFDM-IDMA to pursue the external information reconstruction signal in the chip iterative detection; On the one hand, be used to upgrade the soft information that next iteration detects, on the other hand; Basis as reconstruction signal; Utilize this information and receive data-signal according to formula:
carries out frequency offset estimating, and feedback is carried out compensate of frequency deviation again, through the mode of iteration; Circulation is carried out and is estimated and compensation; Precision that has improved frequency offset estimating and the performance of having optimized system link, the performance in the time of can making the systematic function that receives the carrier wave frequency offset interference approach no frequency deviation gradually, the carrier synchronization of realization system.
Disclosed all characteristics in this specification, or the step in disclosed all methods or the process except mutually exclusive characteristic and/or the step, all can make up by any way.
Disclosed arbitrary characteristic in this specification (comprising any accessory claim, summary and accompanying drawing) is only if special narration all can be replaced by other equivalences or the alternative features with similar purpose.That is, only if special narration, each characteristic is an example in a series of equivalences or the similar characteristics.
The present invention is not limited to aforesaid embodiment.The present invention expands to any new feature or any new combination that discloses in this manual, and the arbitrary new method that discloses or step or any new combination of process.
Claims (9)
1. one kind based on by the iteration carrier synchronization method of chip iterative detection, it is characterized in that, comprising:
IDMA is carried out reconstruct by the external information that produces in the chip iterative detection at every turn, obtain reconstruction signal;
Reconstruction signal according to obtaining in reception signal in the IDMA current iteration testing process and the last iterative detection process carries out frequency offset estimating, obtains current frequency offset estimating value;
Said current frequency offset estimating value is used for the frequency deviation that the current iteration testing process produces is compensated.
2. the method for claim 1 is characterized in that, in first time iterative detection process, with first frequency offset estimating value the frequency deviation that produces in the iterative detection process first time is compensated.
3. method as claimed in claim 2 is characterized in that, saidly obtains current frequency offset estimating value and specifically comprises:
According to the reconstruction signal that obtains in reception signal in the IDMA current iteration testing process and the last iterative detection process according to formula:
carries out frequency offset estimating; Obtain current frequency offset estimating value; Wherein
is for receiving signal;
for utilizing the signal of external information reconstruct,
is channel frequency response.
4. method as claimed in claim 2 is characterized in that, said first frequency offset estimating value is come out according to the maximal possibility estimation algorithm computation.
5. one kind based on by the OFDM-IDMA carrier synchronization system of chip iterative detection; Comprise: OFDM modulator, ofdm demodulator and IDMA receiver; Said IDMA receiver is a multi-user detector; Behind the signal interpolation additive white Gaussian noise of OFDM modulator output, be input to ofdm demodulator, it is characterized in that said system also comprises frequency deviation estimating modules and compensate of frequency deviation module;
Said multi-user detector carries out reconstruct by the external information that produces in the chip iterative detection with IDMA at every turn, obtains reconstruction signal;
Said frequency deviation estimating modules is carried out frequency offset estimating according to the reconstruction signal that obtains in reception signal in the IDMA current iteration testing process and the last iterative detection process, obtains current frequency offset estimating value;
Said compensate of frequency deviation module is used for said current frequency offset estimating value the frequency deviation that the current iteration testing process produces is compensated.
6. system as claimed in claim 5 is characterized in that, said system also comprises: first frequency deviation estimating modules is used to calculate first frequency offset estimating value;
Said compensate of frequency deviation module compensates the frequency deviation that produces in the iterative detection process first time with first frequency offset estimating value in first time iterative detection process.
7. system as claimed in claim 6 is characterized in that, said ofdm demodulator further comprises: remove cyclic prefix unit, FFT carrier wave demodulation device and IDFT carrier wave demodulation device.
8. system as claimed in claim 7 is characterized in that, said OFDM modulator further comprises: DFT unit, subcarrier map unit, IFFT carrier modulation unit and add cyclic prefix unit.
9. like claim 7 or 8 described systems, it is characterized in that said multi-user detector further comprises: baseband signal estimator ESE, single user's posterior probability APP decoder despreader and decoder DEC.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012100214209A CN102437995A (en) | 2012-01-31 | 2012-01-31 | Iterative carrier synchronizing method and system based on code-by-code iterative detection |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012100214209A CN102437995A (en) | 2012-01-31 | 2012-01-31 | Iterative carrier synchronizing method and system based on code-by-code iterative detection |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN102437995A true CN102437995A (en) | 2012-05-02 |
Family
ID=45985874
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2012100214209A Pending CN102437995A (en) | 2012-01-31 | 2012-01-31 | Iterative carrier synchronizing method and system based on code-by-code iterative detection |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN102437995A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102904690A (en) * | 2012-10-15 | 2013-01-30 | 复旦大学 | Method and device for restraining inter-cell interference of high level modulating signal based on OFDM-IDMA (Orthogonal Frequency Division Multiplexing-Interleave-division Multiple Access) |
| CN104580054A (en) * | 2014-12-08 | 2015-04-29 | 复旦大学 | Iterative inter-cell interference suppression method and device |
| CN108712189A (en) * | 2018-05-29 | 2018-10-26 | 电子科技大学 | The multi-user test method of combination approximation message transmission for interlacing multi-address system |
| CN108712234A (en) * | 2018-05-23 | 2018-10-26 | 电子科技大学 | A kind of frequency deviation detection method under the interlacing multi-address technology of combination coordinate descent |
| CN108768590A (en) * | 2018-05-23 | 2018-11-06 | 电子科技大学 | A kind of multi-user test method for interlacing multi-address system |
| CN113258984A (en) * | 2021-04-29 | 2021-08-13 | 东方红卫星移动通信有限公司 | Multi-user self-adaptive frequency offset elimination method and device and low-orbit satellite communication system |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2002033838A2 (en) * | 2000-10-20 | 2002-04-25 | Nortel Networks Limited | Multi-user detector for direct sequence - code division multiple access (ds/cdma) channels |
| CN1463084A (en) * | 2003-06-18 | 2003-12-24 | 中国人民解放军理工大学通信工程学院 | Method and device of iterative demodulation and decode for BPSK modulating system by Turbo encoding |
| WO2006042326A1 (en) * | 2004-10-12 | 2006-04-20 | Qualcomm Incorporated | Log-likelihood estimation based on channel estimation errors due to guard subbands |
| CN101505290A (en) * | 2009-03-17 | 2009-08-12 | 山东大学 | Improved frequency bias estimation method for wideband MIMO |
-
2012
- 2012-01-31 CN CN2012100214209A patent/CN102437995A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2002033838A2 (en) * | 2000-10-20 | 2002-04-25 | Nortel Networks Limited | Multi-user detector for direct sequence - code division multiple access (ds/cdma) channels |
| CN1463084A (en) * | 2003-06-18 | 2003-12-24 | 中国人民解放军理工大学通信工程学院 | Method and device of iterative demodulation and decode for BPSK modulating system by Turbo encoding |
| WO2006042326A1 (en) * | 2004-10-12 | 2006-04-20 | Qualcomm Incorporated | Log-likelihood estimation based on channel estimation errors due to guard subbands |
| CN101505290A (en) * | 2009-03-17 | 2009-08-12 | 山东大学 | Improved frequency bias estimation method for wideband MIMO |
Non-Patent Citations (1)
| Title |
|---|
| 禹永植等: "《BICM-OFDM系统中基于ML算法的迭代频偏估计》", 《信号处理》 * |
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102904690A (en) * | 2012-10-15 | 2013-01-30 | 复旦大学 | Method and device for restraining inter-cell interference of high level modulating signal based on OFDM-IDMA (Orthogonal Frequency Division Multiplexing-Interleave-division Multiple Access) |
| CN104580054A (en) * | 2014-12-08 | 2015-04-29 | 复旦大学 | Iterative inter-cell interference suppression method and device |
| CN104580054B (en) * | 2014-12-08 | 2018-07-27 | 复旦大学 | The method and apparatus of AF panel between a kind of iteration adjacent cell |
| CN108712234A (en) * | 2018-05-23 | 2018-10-26 | 电子科技大学 | A kind of frequency deviation detection method under the interlacing multi-address technology of combination coordinate descent |
| CN108768590A (en) * | 2018-05-23 | 2018-11-06 | 电子科技大学 | A kind of multi-user test method for interlacing multi-address system |
| CN108712234B (en) * | 2018-05-23 | 2021-02-26 | 电子科技大学 | Frequency offset detection method under interleaved multiple access technology combined with coordinate descent method |
| CN108768590B (en) * | 2018-05-23 | 2021-04-23 | 电子科技大学 | Multi-user detection method for interleaving multi-address system |
| CN108712189A (en) * | 2018-05-29 | 2018-10-26 | 电子科技大学 | The multi-user test method of combination approximation message transmission for interlacing multi-address system |
| CN108712189B (en) * | 2018-05-29 | 2019-12-27 | 电子科技大学 | Multi-user detection method combined with approximate message transmission for interleaving multi-address system |
| CN113258984A (en) * | 2021-04-29 | 2021-08-13 | 东方红卫星移动通信有限公司 | Multi-user self-adaptive frequency offset elimination method and device and low-orbit satellite communication system |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Vasudevan | Coherent detection of turbo-coded OFDM signals transmitted through frequency selective Rayleigh fading channels with receiver diversity and increased throughput | |
| US7733993B2 (en) | Phase noise canceling OFDM receiver | |
| CN102437995A (en) | Iterative carrier synchronizing method and system based on code-by-code iterative detection | |
| EP1836817A2 (en) | System and method for utilizing different known guard intervals in single/multiple carrier communication systems | |
| KR20170060112A (en) | Multi-user code division multiple access communication method, and corresponding transmitter and receiver | |
| US11476975B2 (en) | Systems and methods for multi-carrier signal echo management using pseudo-extensions | |
| CN102547740A (en) | Interference elimination method and device, and communication system | |
| KR20100129204A (en) | Methods and apparatus for simultaneous estimation of frequency offset and channel response for mu-mimo ofdma | |
| Shaboyan et al. | Frequency and timing synchronization for in-band full-duplex OFDM system | |
| Cai et al. | General carrier index aided dual-mode differential chaos shift keying with full mapping: Design and optimization | |
| US8982685B2 (en) | Time orthogonalization of reference signals | |
| KR101886525B1 (en) | Method and appratus for removing inter carrier interference by frequency offset in noma system | |
| CN108712189B (en) | Multi-user detection method combined with approximate message transmission for interleaving multi-address system | |
| Dang et al. | Experimental results on OFDM-IDMA communications with carrier frequency offsets | |
| US11102043B2 (en) | Systems and methods for OFDM duobinary transmission | |
| US20210399936A1 (en) | Systems and methods for ofdm duobinary transmission | |
| Abhayawardhana et al. | Residual frequency offset correction for coherently modulated OFDM systems in wireless communication | |
| Wang et al. | EM-based adaptive frequency domain estimation of Doppler shifts with CRLB analysis for CDMA systems | |
| CN108712234B (en) | Frequency offset detection method under interleaved multiple access technology combined with coordinate descent method | |
| Ahmed et al. | An efficient algorithm for CFO estimation in FBMC and GFDM under SUI channel models | |
| CN110365617B (en) | Multi-user orthogonal frequency division multiple access receiving method and device based on space-time reference | |
| Chinchilla | Synchronization and channel estimation in OFDM: algorithms for efficient implementation of WLAN systems | |
| Mioso et al. | An SDR-based reconfigurable multicarrier transceiver for terrestrial and satellite communications | |
| Chakraborty et al. | EM based joint estimation of frequency offsets and channel gains for TWR-OFDM systems | |
| Cai et al. | Design of Carrier Index Keying-Aided M-ary Differential Chaos Cyclic Shift Keying for D2D Communications |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C12 | Rejection of a patent application after its publication | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20120502 |