CN1588936A - Orthogonal frequency division multiplexing transmission system with self adaption protective interval - Google Patents
Orthogonal frequency division multiplexing transmission system with self adaption protective interval Download PDFInfo
- Publication number
- CN1588936A CN1588936A CN 200410052986 CN200410052986A CN1588936A CN 1588936 A CN1588936 A CN 1588936A CN 200410052986 CN200410052986 CN 200410052986 CN 200410052986 A CN200410052986 A CN 200410052986A CN 1588936 A CN1588936 A CN 1588936A
- Authority
- CN
- China
- Prior art keywords
- input
- output
- data
- serial
- channel
- 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
- 230000005540 biological transmission Effects 0.000 title claims abstract description 33
- 230000001681 protective effect Effects 0.000 title 1
- 230000003044 adaptive effect Effects 0.000 claims abstract description 12
- 239000011159 matrix material Substances 0.000 claims description 15
- 238000006243 chemical reaction Methods 0.000 claims description 8
- 238000007493 shaping process Methods 0.000 claims description 6
- 238000001914 filtration Methods 0.000 claims description 4
- 238000001228 spectrum Methods 0.000 claims description 4
- 238000005562 fading Methods 0.000 description 6
- 230000011664 signaling Effects 0.000 description 5
- 230000006854 communication Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 238000004891 communication Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000007476 Maximum Likelihood Methods 0.000 description 2
- 230000001186 cumulative effect Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000000284 extract Substances 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 238000010295 mobile communication Methods 0.000 description 2
- 238000005070 sampling Methods 0.000 description 2
- 230000006978 adaptation Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000012512 characterization method Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000009432 framing Methods 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 230000009897 systematic effect Effects 0.000 description 1
Images
Landscapes
- Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
Abstract
This invention relates to an orthogonal FDM transmission system with adaptive protection interval including a sender and a receiver in time division duplex mode, among which, the sender includes a protection interval controller, the receiver includes a channel evaluator. The channel evaluator of the receiver can evaluate the multipath time delay in a wireless mobile environment to send the evaluated mean square root time delay expansion to the protect interval controller which adaptively regulates the protect interval of the orthogonal FDM transmission symbols of the sender keeping 2-3 times that of the channel square root time delay expansion.
Description
Technical field
The present invention relates to wireless digital mobile communication technology field, be specifically related to a kind of OFDM transmission system with adaptive guard interval.
Background technology
In radio communication, signal of communication will be subjected to usually because the frequency selective fading that causes of multipath transmisstion, narrow band interference, the influence of the time selective fading that Doppler frequency shift causes etc.Disturb ISI (Inter Symbol Interference) between the direct result is-symbol of frequency selective fading.Particularly for high-speed radiocommunication, because the time ratio that each symbol continued is shorter, ISI is just more serious.For traditional single-carrier system, in order to tackle the ISI that frequency selectivity causes, need the very long equalizer of progression usually, hardware complexity is very high.Existing OFDM (OFDM) has solved the problem of ISI by adopting following two kinds of measures simultaneously.The one, data flow at a high speed is divided into the data flow of N low speed, and with parallel transmission on the subcarrier of N quadrature of these data stream modulates, owing to the bandwidth of each subcarrier all less than the coherence bandwidth of channel, so each subcarrier will be similar to the experience flat fading; The 2nd, before sending, each data symbol all adds the preceding paragraph circulation section prefix, the some quick inverse-Fourier transforms of afterbody (IFFT) sample that is about to each symbol transmissions that circulate in advance, this segment signal also claims the protection interval.Like this; when multipath fading causes intersymbol interference; be not more than protection length at interval as long as the time span that intersymbol interference continues is the time delay expansion of channel, just can from received OFDM symbol, extract the part that symbol interference influences before and after not being subjected to substantially and carry out demodulation.
But in present ofdm system, protection length at interval all is to pre-determine and changeless always in whole communication process.This changeless circulation section prefix length normally selects in the applied environment under the worst case or root mean square (RMS) time delay on the average meaning is expanded and designed, thereby often in transmission symbol, accounted for bigger ratio, caused the decline of power resource and channel resource utilance.Because the channel that radio communication channel becomes the time often, the mobile subscriber difference constantly, the multipath fading situation that experienced on diverse location and the different directions also is constantly to change, caused channel delay expansion also constantly changes.Fig. 4 is the time delay expansion cumulative probability density profile of a typical wireless application environment, be illustrated in the distribution situation of the situation lower channel time delay expansion of moving the user in the typical environment, this typical curve is selected from Rapport, T.S. classical paper " Characterization of UHFMultipath Radio Channels in Factory Buildings; " Antennas andPropagation, IEEE Transactions on, vol.37, NO.8, pp1058-1069, Aug 1989.This curve shows that the time delay expansion of actual wireless channel is constantly to change.
Therefore, following two kinds of situations will appear in wireless transmitting system design and use process: the one, and actual RMS multidiameter delay ratio design load is big, and the 2nd, actual RMS multidiameter delay ratio design load is little.For the previous case, consequence is exactly that system exists very serious intersymbol interference, thereby influences the performance of system.For latter event, long protection is a kind of redundancy to system at interval, has wasted valuable frequency spectrum resource.Therefore the definite protection gap length of this static state is not optimum for the mobile wireless ofdm system.
Summary of the invention
The purpose of this invention is to provide a kind of OFDM transmission system with adaptive guard interval, this system can estimate in real time to the multidiameter delay situation of environment of living in, and expand protection that self adaptation adjusts the OFDM transmission symbol at interval according to the root mean square time delay that estimates, make protection length at interval remain 2～3 times that channel root mean square time delay is expanded, like this when actual channel root mean square time delay ratio hour, this system can save and be used to protect signal energy and system bandwidth at interval; And when the expansion of root mean square time delay was big, the system that can guarantee again was not subjected to the influence of intersymbol interference, thereby obtained optimum power and bandwidth availability ratio under the situation that guarantees systematic function.
In order to achieve the above object; OFDM transmission system with adaptive guard interval of the present invention comprises transmitter and the receiver that is operated under the TDD mode; wherein, transmitter comprises serial-parallel converter, anti-fast fourier transformer (IFFT), parallel to serial converter, protection interval controller and sends forming filter:
Serial-parallel converter is used for the data conversion of serial input is parallel data;
Anti-fast fourier transformer (IFFT), the output and the pilot data of its input termination serial-parallel converter are used for the parallel data and the pilot data of input are carried out the OFDM modulation;
Parallel to serial converter, its input links to each other with the output of anti-fast fourier transformer, and being used for the data conversion after the OFDM modulation is serial data;
The protection interval controller, be used to adjust the protection length at interval of next frame OFDM transmission symbol, the output of the output of its input and parallel to serial converter and the channel estimator of receiver links to each other, and output links to each other with the input that sends forming filter;
Send forming filter, the data sequence of coming the self-shield interval controller is carried out spectrum shaping filtering, obtain baseband signal s (t) and outwards send;
Receiver comprises reception forming filter, serial-parallel converter, fast fourier transformer (FFT), channel estimator and equilibrium and detector:
Receive forming filter, the baseband signal r (t) that receives is mated shaping filter, the input of its output termination serial-parallel converter;
Serial-parallel converter is used for the data of serial are converted to parallel data, and its output links to each other with the input of fast fourier transformer (FFT);
Fast fourier transformer (FFT) is carried out the demodulation of OFDM to the data of input, and its output links to each other with the input of channel estimator and the input of equilibrium and detector respectively;
Channel estimator, be used for estimating channel response, estimating root mean square (RMS) the time delay expansion of channel by channel response again from pilot data, its input links to each other with the output of fast fourier transformer, and two outputs link to each other with the protection interval controller of transmitter and the equilibrium and the detector of receiver respectively;
Equilibrium and detector are used for the input data are carried out adjudicating output again behind the frequency domain equalization, and its input links to each other with the output of channel estimator and the output of fast fourier transformer.
The channel estimator of above-mentioned receiver can be made up of matrix operation unit, channel estimating fast fourier transformer, time delay expansion computing unit, the input of matrix operation unit links to each other with the output of the fast fourier transformer of receiver, its output divides two-way, links to each other with the input of channel estimating fast fourier transformer with time delay expansion computing unit respectively.
The protection interval controller of transmitter can be at interval the length of protection that becomes each OFDM transmission symbol in the next frame of the size conversion with the root mean square time delay expansion of channel estimator output, and adjust protection digital signal processor or programmable gate array at interval in view of the above.Wherein, the protection of said next frame OFDM transmission symbol length at interval is 2～3 times of root mean square time delay expansion of channel estimator output.
Native system is simple in structure, and computational complexity is not high.Because native system can be according to the characteristics of channel; dynamically change its protection length at interval; therefore under typical wireless mobile communications environment, can significantly improve the transmission rate of system; and can reduce system and spend in the energy of protecting on the interval; thereby reduced the power consumption that mobile system comprises transmitting-receiving two-end, increased bandwidth availability ratio.
Description of drawings
Fig. 1 is a system architecture diagram of the present invention;
Fig. 2 is the frame format figure that transmitter transmits data;
Fig. 3 is a kind of concrete formation schematic diagram of native system channel estimator;
Fig. 4 is the time delay expansion cumulative probability density profile of a typical application example;
Fig. 5 is root mean square time delay estimated mean-square (MSE) curve in the above-mentioned typical application example;
Fig. 6 is the error rate comparative graph of native system and legacy system.
Embodiment
The present invention is further described below in conjunction with drawings and Examples.
With reference to Fig. 1; OFDM transmission system with adaptive guard interval of the present invention; comprise the transmitter and the receiver that are operated under the TDD mode; wherein, transmitter comprises serial-parallel converter 1, anti-fast fourier transformer (IFFT) 2, parallel to serial converter 3, protection interval controller 4 and sends forming filter 5:
Serial-parallel converter 1 is used for the data conversion of serial input is parallel data;
Anti-fast fourier transformer (IFFT) 2, the output and the pilot data of its input termination serial-parallel converter 1 are used for the parallel data and the pilot data of input are carried out the OFDM modulation;
Parallel to serial converter 3, its input links to each other with the output of anti-fast fourier transformer 2, and being used for the data conversion after the OFDM modulation is serial data;
Protection interval controller 4, the size that channel root mean square (RMS) time delay that is used for estimating in real time according to receiver channel estimator 9 is expanded is adjusted the protection length at interval of next frame OFDM transmission symbol, the output of the output of its input and parallel to serial converter 3 and the channel estimator 9 of receiver links to each other, and output links to each other with the input that sends forming filter 5;
Send forming filter 5, the data sequence of coming self-shield interval controller 4 is carried out spectrum shaping filtering, obtain baseband signal s (t) and outwards send; Can adopt but be not limited to FIR, iir filter is realized.
Receiver comprises reception forming filter 6, serial-parallel converter 7, fast fourier transformer (FFT) 8, channel estimator 9 and equilibrium and detector 10:
Receive forming filter 6, the baseband signal r (t) that receives is mated shaping filter, the input of its output termination serial-parallel converter 7;
Serial-parallel converter 7 is finished the serial-to-parallel conversion of data-signal, and its output links to each other with the input of fast fourier transformer (FFT) 8;
Fast fourier transformer (FFT) 8 is carried out the demodulation of OFDM to the data of input, and its output links to each other with the input of channel estimator 9 and the input of equilibrium and detector 10;
Channel estimator 9 is used for estimating in real time from the dateout of fast fourier transformer 8 frequency response of channel, and the result is delivered to equilibrium and detector 10 carries out channel compensation and symbol judgement; Also calculate root mean square time delay expansion simultaneously, and the protection interval controller 4 of the result being delivered to transmitter is to adjust the symbol protection at interval according to the frequency response that is obtained; Its input links to each other with the output of fast fourier transformer 8, and two outputs link to each other with the protection interval controller 4 of transmitter and the equilibrium and the detector 10 of receiver respectively;
Equilibrium and detector 10, its input links to each other with the output of channel estimator 9 and the output of fast fourier transformer 8, and the input data are carried out adjudicating output again behind the frequency domain equalization.
Above-mentioned transmitter and receiver can adopt programmable gate array or digital signal processor to realize.For example, programmable gate array can adopt the APEX20K600 of altera corp, and digital signal processor can adopt the TMS320GLZ6416 of TI company.
Transmitter sends Frame according to the frame format among Fig. 2.Each physical frame is divided into three parts, is respectively the preamble word part, signaling signal part, and last data field part.Preamble word partly is used for auxiliary receiver and finishes frame-grab, clock synchronization, and carrier wave recoveries etc. are for the very important work of burst system.Signaling moiety is used for informing the other side, and this sends the total length and the employed protection length at interval of data.Take 12bit and 6bit respectively, and fill 0 in the back, form a complete OFDM symbol.For the transmission that guarantees signaling moiety is correct, preamble word partly adopts 1/2 error correction coding protection, and transmits with BPSK.The sampling time of system is T
sSub-carrier number is total up to N
T, N wherein
DIndividually be used for passing data, N
pIndividual is pilot data, all the other N
zIndividual subcarrier is made as 0, and therefore the data field duration of an OFDM symbol is T
sN
TProtection number of samples N at interval
gBe variable.
During work, receiver carries out filtering to baseband receiving signals r (t) with receiving forming filter 6 earlier, and sampling obtains digital baseband signal then, and it is sent to reception serial-parallel converter 7.To N wherein again
gIndividual protection is removed at interval, here N
gDetermine to be divided into two kinds of situations:
1. current sign is preamble word and signal part, then N
gValue fix, be the maximum protection gap length that system supports:
2. current sign is data, so N
gJust equal this frame protection gap length territory (see figure 2) among the signaling signal.
The data of removing after protecting at interval are fed to the demodulation that fast fourier transformer 8 is finished the OFDM symbol.Then from wherein with N
pIndividual pilot data takes out sends into channel estimator 9, remaining N
DIndividual data are sent to equilibrium and detector 10 carries out the balanced and judgement of conventional orthogonal division multiplexed transmission system, obtain signaling (Signal) territory and data.
The effect of channel estimator 9 is response and the expansions of RMS time delay that estimate on each subchannel.The subchannel response is sent to the equilibrium that is used in equilibrium and the detector 10 data.And RMS time delay extend information is delivered to the protection length at interval that is used to determine transmission next time in the protection interval controller 4.
Constitute schematic diagram referring to channel estimator shown in Figure 39.Receiver takes out the pilot data that receives forms a vectorial R
p=[R (i
0) ..., R (i
P-1)]
TThese data at first are sent among the matrix operation unit 9-1.Its effect is the multipath information that extracts time domain from the pilot signal of these frequency domains
The coefficient of converter is to derive through maximum-likelihood criterion to obtain.The coefficient of the converter that obtains according to maximum-likelihood criterion is E
-1F
HWherein:
[F]
N, k=exp (j2 π ki
n/ N), be the fourier coefficient matrix:
E=F
HF is the autocorrelation matrix of fourier coefficient matrix; And F
HExpression is got its complex conjugate to matrix F.
The channel multi-path information that matrix operation unit 9-1 is estimated
Deliver to the value that channel estimating fast fourier transformer (FFT) 9-2 module just obtains the channel response on each subcarrier
Simultaneously multipath information is sent into the estimated value that time delay expansion computing unit 9-3 just can obtain the multidiameter delay expansion
Definition according to it calculates:
Protection length N at interval
gJust be made as
The smallest positive integral that expression is bigger than x, coefficient 2 can be other numerical value between 2～3 here.Transmitter carries out framing according to data frame format shown in Figure 2 then, and successively with N
DIndividual data are sent into and are sent serial-parallel converter 1, simultaneously at position { i
n0≤n≤N
P-1Locate to add N
pIndividual pilot data { p
n0≤n≤Nx-1}, and add N
z Individual data 0 obtain N
TIndividual transmission data.These data are sent to anti-fast fourier transformer (IFFT) 2 finish the OFDM modulation.After data after anti-fast fourier transform is finished are sent in the parallel to serial converter 3, become the data of serial.The effect of protection interval controller 4 is to add before the data of serial
Individual protection at interval.Be sent to the transmission data s (t) that transmission formed filter 5 obtains base band through the data that add after protecting at interval.
At typical wireless application environment shown in Figure 4, can obtain under this typical wireless application environment by emulation, native system can also on average improve the transmission rate of 11.536Mb/s than legacy system to save under the power situation of 0.6454dB than legacy system.
Fig. 5 has shown the mean square error figure of the employed RMS time delay of native system spread estimation method under above-mentioned typical radio environment.Can see that the value of MSE is less than 10 when signal to noise ratio during greater than 10dB
-2. in this case, transceiver just can almost not have the due protection of wrong selection length at interval.
Fig. 6 has shown the comparison diagram of the bit error rate of native system and legacy system under above-mentioned typical radio environment, among the figure, Δ is represented the ber curve of native system, * the ber curve of representing legacy system can see that native system obtains the performance of BER close with legacy system under the situation of more low-yield higher rate transmission.
Claims (6)
1. the OFDM transmission system that has adaptive guard interval; it is characterized in that it comprises transmitter and the receiver that is operated under the TDD mode; wherein, transmitter comprises serial-parallel converter (1), anti-fast fourier transformer (2), parallel to serial converter (3), protection interval controller (4) and sends forming filter (5):
Serial-parallel converter (1) is used for the data conversion of serial input is parallel data;
Anti-fast fourier transformer (2), the output and the pilot data of its input termination serial-parallel converter (1) are used for the parallel data and the pilot data of input are carried out the OFDM modulation;
Parallel to serial converter (3), its input links to each other with the output of anti-fast fourier transformer (2), and being used for the data conversion after the OFDM modulation is serial data;
Protection interval controller (4), be used to adjust the protection length at interval of next frame OFDM transmission symbol, the output of the output of its input and parallel to serial converter (3) and the channel estimator (9) of receiver links to each other, and output links to each other with the input that sends forming filter (5);
Send forming filter (5), the data sequence of coming self-shield interval controller (4) is carried out spectrum shaping filtering, obtain baseband signal s (t) and outwards send;
Receiver comprises reception forming filter (6), serial-parallel converter (7), fast fourier transformer (8), channel estimator (9) and equilibrium and detector (10):
Receive forming filter (6), the baseband signal r (t) that receives is mated shaping filter, the input of its output termination serial-parallel converter (7);
Serial-parallel converter (7) is used for the data of serial are converted to parallel data, and its output links to each other with the input of fast fourier transformer (8);
Fast fourier transformer (8) is carried out the demodulation of OFDM to the data of input, and its output links to each other with the input of channel estimator (9) and the input of equilibrium and detector (10);
Channel estimator (9), be used for estimating channel response, estimating the root mean square time delay expansion of channel by channel response again from pilot data, its input links to each other with the output of fast fourier transformer (8), and two outputs link to each other with the protection interval controller (4) of transmitter and the equilibrium and the detector (10) of receiver respectively;
Equilibrium and detector (10) are used for the input data are carried out adjudicating output again behind the frequency domain equalization, and its input links to each other with the output of channel estimator (9) and the output of fast fourier transformer (8).
2. the OFDM transmission system with adaptive guard interval according to claim 1 is characterized in that said transmitter and receiver are programmable gate array or digital signal processor.
3. the OFDM transmission system with adaptive guard interval according to claim 1; it is characterized in that channel estimator (9) is made up of matrix operation unit (9-1), channel estimating fast fourier transformer (9-2), time delay expansion computing unit (9-3); the input of matrix operation unit (9-1) links to each other with the output of the fast fourier transformer (8) of receiver; its output divides two-way, links to each other with the input of channel estimating fast fourier transformer (9-2) with time delay expansion computing unit (9-3) respectively.
4. the OFDM transmission system with adaptive guard interval according to claim 3 is characterized in that said matrix operation unit (9-1) is input pilot data vector to be finished with the fourier coefficient matrix be the matrixing of the factor and be that the matrixing of the factor is to obtain the digital signal processor or the programmable gate array of channel time domain response with the autocorrelation matrix of fourier coefficient matrix.
5. the OFDM transmission system with adaptive guard interval according to claim 3 is characterized in that said time delay expansion computing unit (9-3) is digital signal processor or the programmable gate array that is estimated the root mean square time delay expansion of channel by the channel time domain response of matrix operation unit (9-1) output.
6. the OFDM transmission system with adaptive guard interval according to claim 1, the protection length at interval that it is characterized in that the next frame OFDM transmission symbol that said protection interval controller (4) is adjusted are 2～3 times that the root mean square time delay of channel estimator (9) output is expanded.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200410052986 CN1588936A (en) | 2004-07-15 | 2004-07-15 | Orthogonal frequency division multiplexing transmission system with self adaption protective interval |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200410052986 CN1588936A (en) | 2004-07-15 | 2004-07-15 | Orthogonal frequency division multiplexing transmission system with self adaption protective interval |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1588936A true CN1588936A (en) | 2005-03-02 |
Family
ID=34602689
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 200410052986 Pending CN1588936A (en) | 2004-07-15 | 2004-07-15 | Orthogonal frequency division multiplexing transmission system with self adaption protective interval |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1588936A (en) |
Cited By (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2010006511A1 (en) * | 2008-07-16 | 2010-01-21 | 中国移动通信集团公司 | Method for improving frequency spectrum utilization ratio in tdd system and tdd system |
| CN101090386B (en) * | 2007-07-05 | 2010-05-19 | 中国科学院上海微系统与信息技术研究所 | Block transmission system frequency field demodulation device based on filter set and its method |
| CN101005344B (en) * | 2006-01-19 | 2010-08-18 | 中兴通讯股份有限公司 | Signal transmission method between base station and mobile station |
| CN101132200B (en) * | 2006-08-23 | 2010-09-15 | 北京信威通信技术股份有限公司 | Method and system for adjusting protection time slot |
| US7848447B2 (en) | 2005-04-28 | 2010-12-07 | Ntt Docomo, Inc. | Radio parameter group generating apparatus, transmitter and receiver |
| CN101409699B (en) * | 2008-11-28 | 2011-03-30 | 清华大学 | Signal transmission method for wideband wireless mobile commutation system |
| CN101127745B (en) * | 2006-08-16 | 2011-09-14 | 大唐移动通信设备有限公司 | A chancel estimation method and device |
| CN101356755B (en) * | 2005-08-18 | 2011-11-23 | 摩托罗拉移动公司 | Method and apparatus for pilot signal transmission |
| CN101331726B (en) * | 2005-12-14 | 2012-05-09 | 艾利森电话股份有限公司 | Method and device for signal processing |
| CN101502030B (en) * | 2006-08-10 | 2012-09-05 | 京瓷株式会社 | OFDM communication device and guard interval length determining method |
| WO2012171268A1 (en) * | 2011-06-14 | 2012-12-20 | 中兴通讯股份有限公司 | Time-division duplex filtering method and device |
| CN104641711A (en) * | 2012-07-24 | 2015-05-20 | 瑞典爱立信有限公司 | Systems, methods and devices for reducing impact of fading dips on wireless backhaul channels |
| CN104735013A (en) * | 2013-12-18 | 2015-06-24 | 英特尔公司 | Adaptive Channel Prediction and Mitigating Interference in OFDM Systems |
| CN108476192A (en) * | 2016-01-26 | 2018-08-31 | 索尼公司 | device and method |
| CN113271196A (en) * | 2021-04-07 | 2021-08-17 | 北京邮电大学 | Short guard interval orthogonal frequency division multiplexing wireless transmission method |
-
2004
- 2004-07-15 CN CN 200410052986 patent/CN1588936A/en active Pending
Cited By (23)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7848447B2 (en) | 2005-04-28 | 2010-12-07 | Ntt Docomo, Inc. | Radio parameter group generating apparatus, transmitter and receiver |
| US7991064B2 (en) | 2005-04-28 | 2011-08-02 | Ntt Docomo, Inc. | Radio parameter group generating apparatus, transmitter and receiver |
| US8111766B2 (en) | 2005-04-28 | 2012-02-07 | Ntt Docomo, Inc. | Radio parameter group generating apparatus, transmitter and receiver |
| CN101356755B (en) * | 2005-08-18 | 2011-11-23 | 摩托罗拉移动公司 | Method and apparatus for pilot signal transmission |
| CN101331726B (en) * | 2005-12-14 | 2012-05-09 | 艾利森电话股份有限公司 | Method and device for signal processing |
| CN101005344B (en) * | 2006-01-19 | 2010-08-18 | 中兴通讯股份有限公司 | Signal transmission method between base station and mobile station |
| CN101502030B (en) * | 2006-08-10 | 2012-09-05 | 京瓷株式会社 | OFDM communication device and guard interval length determining method |
| CN101127745B (en) * | 2006-08-16 | 2011-09-14 | 大唐移动通信设备有限公司 | A chancel estimation method and device |
| CN101132200B (en) * | 2006-08-23 | 2010-09-15 | 北京信威通信技术股份有限公司 | Method and system for adjusting protection time slot |
| CN101090386B (en) * | 2007-07-05 | 2010-05-19 | 中国科学院上海微系统与信息技术研究所 | Block transmission system frequency field demodulation device based on filter set and its method |
| WO2010006511A1 (en) * | 2008-07-16 | 2010-01-21 | 中国移动通信集团公司 | Method for improving frequency spectrum utilization ratio in tdd system and tdd system |
| CN101409699B (en) * | 2008-11-28 | 2011-03-30 | 清华大学 | Signal transmission method for wideband wireless mobile commutation system |
| WO2012171268A1 (en) * | 2011-06-14 | 2012-12-20 | 中兴通讯股份有限公司 | Time-division duplex filtering method and device |
| CN102833196B (en) * | 2011-06-14 | 2017-02-08 | 中兴通讯股份有限公司 | Time division multiplexing filtration method and device |
| CN104641711A (en) * | 2012-07-24 | 2015-05-20 | 瑞典爱立信有限公司 | Systems, methods and devices for reducing impact of fading dips on wireless backhaul channels |
| CN104641711B (en) * | 2012-07-24 | 2019-06-18 | 瑞典爱立信有限公司 | System, the method and apparatus of influence for reducing decline trough to wireless backhaul channel |
| CN104735013A (en) * | 2013-12-18 | 2015-06-24 | 英特尔公司 | Adaptive Channel Prediction and Mitigating Interference in OFDM Systems |
| CN104735013B (en) * | 2013-12-18 | 2019-01-22 | 英特尔公司 | Adaptability channel prediction and interference mitigation in ofdm system |
| CN108476192A (en) * | 2016-01-26 | 2018-08-31 | 索尼公司 | device and method |
| CN108476192B (en) * | 2016-01-26 | 2021-07-30 | 索尼公司 | Apparatus and method |
| US11296909B2 (en) | 2016-01-26 | 2022-04-05 | Sony Group Corporation | Apparatus and method for performing radio communication |
| CN113271196A (en) * | 2021-04-07 | 2021-08-17 | 北京邮电大学 | Short guard interval orthogonal frequency division multiplexing wireless transmission method |
| CN113271196B (en) * | 2021-04-07 | 2022-03-04 | 北京邮电大学 | Short guard interval orthogonal frequency division multiplexing wireless transmission method |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| AU2004229029B2 (en) | Apparatus and method for sub-carrier allocation in a multiple-input and multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) communication system | |
| EP1755301B1 (en) | Guard interval setting method and apparatus in OFDM communication | |
| CN107306238B (en) | Method for receiving and transmitting carrier modulation signals, and corresponding receiver and transmitter | |
| US8681912B2 (en) | Method and apparatus for estimating channel using phase compensation in wireless communication system | |
| CN101164308B (en) | Timing corrections in a multi carrier system and propagation to a channel estimation time filter | |
| US7773683B2 (en) | Method and apparatus for ICI cancellation in communication systems | |
| US20120063529A1 (en) | Inter-cell interference mitigation method using spatial covariance matrix estimation method for inter-cell interference mitigation of mimo antenna ofdm system | |
| US7952990B1 (en) | Low complexity channel estimation for orthogonal frequency division modulation systems | |
| CN1642051A (en) | Method for obtaining optimum guide symbolic power | |
| US20060198472A1 (en) | Transmission system, transmitter device, and receiver device | |
| CN101502029A (en) | Radio transmission device, radio reception device, radio transmission method, and radio reception method | |
| EP2628254B1 (en) | Uplink noise estimation for virtual mimo | |
| CN1588936A (en) | Orthogonal frequency division multiplexing transmission system with self adaption protective interval | |
| US20100061474A1 (en) | Fft spreading among selected ofdm sub-carriers | |
| EP2192735A1 (en) | Receiving apparatus and method for receiving signals in a wireless communication system with improved equalization performance | |
| JP2004336746A (en) | Apparatus and method for estimating channel in orthogonal frequency division multiplexing system using multiplex antenna | |
| CN101326752A (en) | System, apparatus, and method for single-carrier block transmission with adaptive guard interval | |
| US20050152267A1 (en) | Apparatus and method for canceling interference signal in an orthogonal frequency division multiplexing system using multiple antennas | |
| CN102752253A (en) | Method for inhibiting inter-carrier interference of orthogonal frequency division multiplexing (OFDM) system by time-frequency domain combined processing | |
| EP1253733A1 (en) | Radio transmitting apparatus and radio transmitting method | |
| US9491006B2 (en) | Receiver and reception method for estimating channel in an orthogonal frequency division multiple access system | |
| CN102045285A (en) | Channel estimation method and device and communication system | |
| US20100266078A1 (en) | Radio communication device, and reception quality estimation method | |
| CN108768914B (en) | Efficient frequency division multiplexing transmission method and transmission system combining orthogonal and non-orthogonal | |
| CN1719817A (en) | The pilot transmission of orthogonal FDM communication system and method for reseptance |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C02 | Deemed withdrawal of patent application after publication (patent law 2001) | ||
| WD01 | Invention patent application deemed withdrawn after publication |