CN101808067B - Method and device thereof for receiving and transmitting OFDM signals by using differential data as pilot frequencies - Google Patents
Method and device thereof for receiving and transmitting OFDM signals by using differential data as pilot frequencies Download PDFInfo
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Abstract
The invention discloses a method and a device thereof for receiving and transmitting OFDM signals by using differential data as pilot frequencies. The method comprises the following steps of: A1, receiving main channel data and additional data to be transmitted; A2, performing interleaving, channel coding and differential modulation operation on the additional data in turn to obtain differential constellation mapping symbols; A3, performing the interleaving, the channel coding and coherence modulation operation on the main channel data in turn to obtain coherence constellation mapping symbols; and A4, inserting the differential constellation mapping symbols into the coherence constellation mapping symbols as pilot data according to a frame structure of OFDM and a preset inserting pattern, forming an OFDM signal frame, and then transmitting the signal frame. The technical scheme of the invention can improve the transmission efficiency and the frequency spectrum utilization ratio of a system.
Description
Technical field
The present invention relates to the signal transmission technology field, relate in particular to a kind of ofdm signal receiving/transmission method and device thereof that utilizes differential data as pilot tone.
Background technology
Recent two decades comes; Along with growing to the radio communication service demand of the develop rapidly of modern communication technology and people; The digital signal transmission system of transmission miscellaneous service is widely used in WLAN, fixed wireless access, wire and wireless DAB and video broadcasting transmission standard (Digital TV broadcasting standard for terrestrial: Digital Television Terrestrial Broadcasting; DTTB); Like European standard digital video broadcast-terrestrial (Digital Video TerrestrialBroadcasting-Terrestrial; DVB-T) and CNS (Digital TelevisionTerrestrial Multimedia Broadcast, DTMB).Along with the evolution of standard, multistage transmission requirements is also more and more simultaneously.Japan's digital television standard uses the One-Segment mode to reach the purpose of multistage transmission.Simultaneously, DVB-H technical support mobile phone TV services have also been released in Europe.The common ground of these standards is that the compatible original terrestrial DTV transmission standard of new mobile TV transmission standard is replenishing of original terrestrial DTV transmission standard.Simultaneously, new business has inevitably increased the complexity of system design.
In the current wireless communication system, be faced with two contradictions, one is the contradiction of growing number of users and limited frequency spectrum resource, another is that the user is to the demand of quality of service and the contradiction of wireless propagation environment.Wherein, the greatest problem that the broadband wireless communications transmission technology faces is, single carrier or multicarrier modulation system can the declines of occurrence frequency selectivity under multi-path channel, i.e. and intersymbol interference (Inter Symbol Interference, ISI).
Simultaneously, user's demand makes communication system need support increasing business.So support the multistage transmission of multiple business just to become the prerequisite key element of communication system.Multiple services multistage transmission, require a communication system can transmission service quality, receive the business that aspects such as scene, data transfer rate and reception complexity have nothing in common with each other.This has just more increased the difficulty and the complexity of system design.For example; The digital terrestrial television transmission system of compatible mobile TV; Just both required system can transmit the HD digital TV programme of the fixing High Data Rate that receives, it is relatively low to require system to support data rate request again, but wants the mobile phone TV services that receive under the mobile environment.How can reduce the complexity of the multistage transmission system of multi-service, become a problem of needing solution badly.
OFDM (Orthogonal Frequency Division Multiplexing; OFDM) technology can realize high rate data transmission reliably in frequency selective fading channels, has been widely used in as in the wireless communication systems such as WLAN, fixed wireless access, DAB and video broadcasting.The OFDM technology is a kind of effective piece transmission technology, and its technological core is made up of the piece modulation technique of block of frequency domain data transmission symbol.The modulation of OFDM piece at first with the synthetic block of frequency domain data of symbols to be transmitted, obtains time-domain data blocks through behind the inverse discrete fourier transform.Time-domain data blocks and block of frequency domain data are two kinds of forms of expression of data block, and the two is DFT or inverse transformation each other.Frequency domain symbol is defined as subcarrier, can be data to be transmitted symbol (effectively subcarrier), also can be nil symbol (virtual subnet carrier wave), or known symbol to be transmitted (pilot tone).According to the mapping relations between transmission symbol and the subcarrier; Having multiple OFDM piece modulation technique, all is that effective subcarrier, parton carrier wave are that virtual subnet carrier wave, parton carrier wave are pilot tone, effectively configurable the and effective subcarrier of number of sub carrier wave center is removable etc. like subcarrier.
For estimating channel information can be regular by specific insertion in the OFDM transmission system with the antagonism channel fading exactly, insert some training symbols as pilot tone.These pilot tones can be resisted channel fading and other interference, thereby help the receiving terminal restoring signal.The direct decision systems of the density of pilot tone and performance is eliminated the channel estimation ability of ISI and the variation of tracking dynamics of channels etc.But intensive pilot data can cause the availability of frequency spectrum to reduce.In traditional transmission system, pilot tone is not carried data, and this just causes the increase along with the system pilot number, and very big decline can appear in the efficient of system.
Summary of the invention
The technical problem that (one) will solve
The objective of the invention is the deficiency to prior art, what proposed a kind of efficiency of transmission that can improve system and the availability of frequency spectrum utilizes the ofdm signal transmission plan of differential data as pilot tone.
(2) technical scheme
For achieving the above object, the invention provides a kind of ofdm signal sending method of utilizing differential data as pilot tone, may further comprise the steps:
A1 receives main channel data waiting for transmission and additional data;
A2, to said additional data interweave successively, chnnel coding and differential modulation computing, obtain difference constellation mapping symbol;
A3, to said main channel data interweave successively, chnnel coding and relevant modulation operation, obtain the coherent constellations mapping symbols;
A4, frame structure and preset insertion pattern according to OFDM are inserted into said difference constellation mapping symbol in the said coherent constellations mapping symbols as pilot data, and constitute the ofdm signal frame, send this ofdm signal frame then.
Wherein, said main channel data and additional data are respectively wideband data and narrow band data, and the two is imported by the outside.
Wherein, in said steps A 2, said differential modulation computing is calculus of differences or the calculus of differences between the multiframe between two frames.
Wherein, in said steps A 2, the differential modulation that said differential modulation computing is the phase bit arithmetic and the differential modulation of amplitude computing.
Wherein, in said steps A 4, said difference constellation mapping symbol is inserted in the said coherent constellations mapping symbols as pilot tone; And the step that constitutes the ofdm signal frame is specially: A41; Said difference constellation mapping symbol is carried out inverse Fourier transform, constitute insetion sequence, simultaneously said coherent constellations mapping symbols is carried out inverse Fourier transform; Behind the composition data body said insetion sequence is inserted into the head or the afterbody of said data volume, synthetic TDS-OFDM signal frame; Perhaps A42 carries out inverse Fourier transform after being inserted into said difference constellation mapping symbol in the said coherent constellations mapping symbols discretely, and inserts Cyclic Prefix, obtains the CP-OFDM signal frame.Perhaps A43; Said difference constellation mapping symbol is carried out inverse Fourier transform and inserts Cyclic Prefix, constitute the pilot signal frame, said difference constellation mapping symbol is carried out inverse Fourier transform and inserts Cyclic Prefix; The composition data signal frame, both mix formation ofdm signal frame.
The present invention also provides a kind of ofdm signal dispensing device that utilizes differential data as pilot tone, comprising:
Data reception module receives main channel data waiting for transmission and additional data;
Difference constellation mapping symbol calculation module, to said additional data interweave successively, chnnel coding and differential modulation computing, obtain difference constellation mapping symbol;
Coherent constellations mapping symbols computing module, to said main channel data interweave successively, chnnel coding and relevant modulation operation, obtain the coherent constellations mapping symbols;
The framing module, frame structure and preset insertion pattern according to OFDM are inserted into said difference constellation mapping symbol in the said coherent constellations mapping symbols as pilot data, and constitute the ofdm signal frame, send this ofdm signal frame then.
The present invention also provides a kind of ofdm signal method of reseptance that utilizes differential data as pilot tone, may further comprise the steps:
B1 recovers the OFDM symbol through Fourier transform, and therefrom extracts difference constellation mapping symbol and coherent constellations mapping symbols;
B2; To difference constellation mapping symbol, divide computing with the differential data demodulation through the guards escorting prisoners, the differential data symbol after being restored; And the differential data symbol after the said recovery carried out channel-decoding and deinterleaving successively, to recover to be modulated at the additional data on the said difference constellation mapping symbol;
B3; The former frame difference constellation mapping symbols after utilization recovers and the accurate differential data symbol of the present frame after the recovery; The difference constellation mapping symbol of the present frame after being restored; And the difference constellation mapping symbol that utilizes the present frame after recovering obtains corresponding channel estimation values of pilot frequency positions as given data; Wherein, the differential data symbol of the accurate differential data symbol of the present frame after the said recovery through the present frame after will recovering carry out hard decision and will recover after additional data interweave successively again and chnnel coding draws afterwards;
B4; The channel estimation values of pilot frequency positions that utilization obtains is carried out channel estimating to said coherent constellations mapping symbols; Obtain channel estimation value to the present frame of coherent constellations mapping symbols; And the channel estimation value of current frame carried out being applied to the demodulation of coherent constellations mapping symbols after the reprocessing, obtain the data after the demodulation.
Wherein, said guards escorting prisoners to divide computing be that guards escorting prisoners between two frames divides the associating guards escorting prisoners between computing or the multiframe to divide computing.
Wherein, In step B3; The acquiring way of the channel estimating of said pilot frequency locations obtains for the pilot tone of having recovered with the multiframe of front behind the additional data symbols hard decision is carried out differential coding; Perhaps with additional data symbols through recompile behind the error correction decode, obtain additional data planisphere through error correction, the pilot tone of having recovered with the front multiframe is again carried out differential coding and is obtained.
The present invention also provides a kind of ofdm signal receiving system that utilizes differential data as pilot tone, comprising:
Data extraction module is recovered the OFDM symbol through Fourier transform, and is therefrom extracted difference constellation mapping symbol and coherent constellations mapping symbols;
Additional data recovers module; To difference constellation mapping symbol; Divide computing with the differential data demodulation through the guards escorting prisoners; Differential data symbol after being restored, and the differential data symbol after the said recovery carried out channel-decoding and deinterleaving successively, to recover to be modulated at the additional data on the said difference constellation mapping symbol;
Channel estimation module; The former frame difference constellation mapping symbols after utilization recovers and the accurate differential data symbol of the present frame after the recovery; The difference constellation mapping symbol of the present frame after being restored; And the difference constellation mapping symbol that utilizes the present frame after recovering obtains corresponding channel estimation values of pilot frequency positions as given data; Wherein, the differential data symbol of the accurate differential data symbol of the present frame after the said recovery through the present frame after will recovering carry out hard decision and will recover after additional data interweave successively again and chnnel coding draws afterwards;
Main channel data is recovered module; The channel estimation values of pilot frequency positions that utilization obtains is carried out channel estimating to said coherent constellations mapping symbols; Obtain channel estimation value to the present frame of coherent constellations mapping symbols; And the channel estimation value of current frame carried out being applied to the demodulation of coherent constellations mapping symbols after the reprocessing, obtain the main channel data after the demodulation.
Technique scheme adopts the differential modulation data to replace the known pilot in traditional OFDM transmission, and then can under the prerequisite of not losing transmission quality, improve power system capacity.
(3) beneficial effect
The side signal transmission case that technical scheme of the present invention proposes has adopted valid data as additional data; And mode to coming framing as pilot data after its processing; And in data handling procedure, combined the characteristics separately of relevant modulation and differential modulation, thereby the efficiency of transmission and the availability of frequency spectrum of system have been improved; Receiving algorithm simple and flexible of the present invention and do not increase main channel data transmission performances and complexity; Additional data receiving algorithm adaptability wherein is strong; The multi-medium data that can be used for mobile channel receives; Simultaneously, the additional data modulation system can be adjusted flexibly, has increased the performance of the multistage reception of system; But the present invention's expanded application scope, and can be applicable to single carrier or multicarrier transmission systems.
Description of drawings
Fig. 1 inserts pattern for the CP-OFDM data volume differential code of the transmission method of the utilization embodiment of the invention;
Fig. 2 is the TDS-OFDM frame structure sketch map of utilization transmission method of the present invention;
Fig. 3 is the CP-OFDM frame structure sketch map of utilization transmission method of the present invention;
Fig. 4 is the digital signal transmission method schematic block diagram of the embodiment of the invention under CP-OFDM;
Fig. 5 is the digital signal transmission method schematic block diagram of the embodiment of the invention under TDS-OFDM;
Fig. 6 A is the sending method flow chart of the embodiment of the invention;
Fig. 6 B is the method for reseptance flow chart of the embodiment of the invention;
Fig. 7 is the performance of transmission method DQPSK (difference quadrature phase shift keying) differential modulation under CP-OFDM of the embodiment of the invention;
Fig. 8 is the performance of transmission method relevant modulation under CP-OFDM of present embodiment, and modulation system is 16QAM (quadrature amplitude modulation).
Embodiment
Below in conjunction with accompanying drawing and embodiment, specific embodiments of the invention describes in further detail.Following examples are used to explain the present invention, but are not used for limiting scope of the present invention.
In the ofdm system of existing wireless transmission, for satisfying receiver synchronously and the demand of channel estimating, transmission signals need carry a large amount of training informations as pilot tone, has taken valuable frequency spectrum resource.For improving the availability of frequency spectrum; Can support simultaneously the requirement of multistage transmission; This numb scheme proposes the pilot modulated additional data is improved the availability of frequency spectrum; The data of pilot modulated can be used for transmitting cell-phone television services or the lower business of other data transfer rate simultaneously, increase the efficiency of transmission of system.
The invention provides a kind of OFDM transmission means that combines relevant modulation and differential modulation.In transmitting terminal (modulated terminal), additional data can be modulated through the multiframe differential mode in modulated terminal, and is inserted in the main channel data as pilot data, carries out framing according to rule then, spreads out of then.At receiving terminal, at first according to specific computing restoring signal frame.Then to also recovering additional data wherein in demodulation; The actual value of the data of channel estimating is made in recovery then, makes at last data volume is carried out channel estimating, obtains the channel estimating of present frame; And carry out the reprocessing of channel estimating, thereby carry out the data demodulates of whole signal frame.
Below specify the transmission method (comprising sending method and method of reseptance) of the embodiment of the invention.
Of background technology, ofdm system has comprised multiple OFDM piece modulation technique and protection interval filling technique.Two instances are respectively that the differential modulation data are made the TDS-OFDM transmission technology of pilot tone and the differential data that inserts the fixed position and made the CP-OFDM transmission technology of pilot tone (can with reference to figure 2～3) in the embodiment of the invention.
Steps A 1 receives main channel data waiting for transmission and additional data; , this additional data can be used for transmitting cell-phone television services or other the lower business of data transfer rate of comparing with main channel data;
Steps A 2: additional data is interweaved and chnnel coding, carry out differential modulation then, obtain difference constellation mapping symbol;
Through interweaving with chnnel coding after, length is the difference sequence of M, additional data is { A
k i}
K=0 M-1The initial frequency domain training sequence of difference is { C
0(k) }
K=0 M-1, then the frequency-domain pilot sequence of first frame does
The initial training sequence modulation of difference does subsequently
Steps A 3: to main channel data interweave, chnnel coding and relevant modulation, obtain the coherent constellations mapping symbols;
Through interweaving with chnnel coding after, i frame frequency domain symbol to be transmitted is { X
i(k) }
K=0 N-1, can select symbol modulation technique arbitrarily.
Steps A 4: according to frame structure and the predetermined certain patterns (as shown in Figure 1 in the present embodiment) of OFDM; Difference constellation mapping symbol is inserted in the coherent constellations mapping symbols sends after constituting the ofdm signal frame, the transmission mode during transmission includes but not limited to transmission modes such as single user, multi-user, single antenna and many antennas;
To the TDS-OFDM system, block of frequency domain data obtains time-domain data blocks { x behind inverse discrete fourier transform
i(k) }
K=0 N-1, the difference sequence that length is M is filled in the protection between the time-domain data blocks at interval.Differentiated frequency domain differential demodulation modulation sequence { C
i(k) }
K=0 M-1Behind inverse discrete fourier transform, can obtain time domain padding sequence { c
1(k) }
K=0 M-1Time-domain data blocks (frame) and padding sequence (frame head) are formed signal frame together.
To the TDS-OFDM system, with { X
i(k) }
K=0 N-1With { c
1(k) }
K=0 M-1Mode according to Fig. 2 is placed, and obtains { S
i(k) }
K=0 N+M-1, conversion obtains { s through IFFT
i(k) }
K=0 N+M-1, then with { s
i(k) }
K=0 N+M-1Back M time domain data be filled into protection at interval, obtain signal frame.
As shown in Figure 4, in this instance, coding is at first knitted carrying out deep friendship behind the data coding with interleaver 1, with the accuracy that guarantees that additional data receives under the fast time variant channel.Simultaneously, interweave behind 2 pairs of every frame additional data codings of coding and interleaver, to guarantee the real-time of pilot tone.
Receive aerial signal, suppose that local receiver time and frequency are synchronous fully, then the present invention in the method for receiving terminal is:
Step B1:, recover the OFDM symbol at receiving terminal.Obtain difference constellation mapping symbol and coherent constellations mapping symbols respectively through channel.
TDS-OFDM structure to instance 1; Take out the time thresholding and do the FFT conversion of difference sequence and relevant modulation sequence respectively, obtain
and
CP-OFDM structure to instance 2; Receiver at first carries out the FFT conversion to data volume; Obtain
and extract corresponding differential code and master data symbol, i.e.
and
respectively
Step B2: to difference constellation mapping symbolic component; Divide computing through the guards escorting prisoners, with the differential data demodulation, the differential data symbol that is restored; And the differential data after the demodulation carried out channel-decoding and deinterleaving, recover to be modulated at the additional data on the difference constellation mapping symbol.
Suppose that pilot tone and data constellation point is respectively,
and
then
Obtain the training sequence that multiframe receives signal frame, divide computing with the additional data demodulation through the guards escorting prisoners, and separate mapping, right
C is arranged
i(k)=C
I-1(k) A
I-1(k), at receiving terminal, can be through separating the additional data that the frequency domain differential demodulation computing obtains modulating, the guards escorting prisoners divides on the computing principle and can be write as between two frames
After additional data symbols carried out error correction decode and deinterleaving, the additional data that just can be restored.
Step B3: utilize former frame difference constellation mapping symbols of recovery and the accurate differential data symbol that present frame recovers, the present frame difference constellation mapping symbol that is restored.And utilize the present frame difference constellation mapping symbol that recovers as given data, obtain the channel estimating of corresponding pilot frequency locations.
To obtain behind the error correction decode data recovered and carry out the error correcting code coding again and interweave, obtain new
Suppose that signal to noise ratio then can be thought at this moment on threshold level
Be approximately equal to A
I-1(k), then can reconstruct C
i(k).Promptly
If receiver is known { C
0(k) }
K=0 M-1, then can recover
As long as remember the training sequence of previous frame and obtain the training sequence of present frame, just can obtain
Step B4: utilize the channel estimating of the pilot frequency locations that obtains, the coherent constellations mapping symbols is carried out channel estimating.Obtain channel estimation value, and utilize the channel estimation value of present frame to carry out reprocessing (comprising common filtering, denoising etc.), be applied to the demodulation of coherent constellations mapping symbols, obtain demodulated data to the present frame of coherent constellations mapping symbols.
Because
Can be similar to and think and equal { C
i(k) }
K=0 M-1, can obtain
The estimated value
that can get channel estimating by the LS criterion obtains can coming data portion to carry out channel estimating reprocessing and equilibrium etc. according to conventional method after this channel estimation value.
To the CP-OFDM system of example 2, the channel estimation methods that is used for ofdm system that the present invention is proposed has carried out Computer Simulation, and main simulation parameter is as shown in table 1, and two kinds of channel models are as shown in table 2.Shown in channel I be the channel model B that Brazil (Brazil) experiment place test is used, channel II is the channel model A that Brazil's experiment place test is used,
Table 1
| Symbol rate | 7.56M symbol/second |
| The sub-carrier modulation | DQPSK，16QAM |
| OFDM sub-carrier number M | 7778 |
| Protection gap length L | 972 |
| Coded system | LDPC(1944，972) LDPC(7488，6096) |
| Differential code inserts pattern | Insert every frame fixed position |
Table 2
Among Fig. 6 and 7, AWGN (Additive White Gaussion Noise) representes additive white Gaussian noise.
The present invention also provides a kind of ofdm signal dispensing device that utilizes differential data as pilot tone, comprising:
Data are divided module, receive main channel data waiting for transmission and additional data;
Difference constellation mapping symbol calculation module, to said additional data interweave successively, chnnel coding and differential modulation computing, obtain difference constellation mapping symbol;
Coherent constellations mapping symbols computing module, to said main channel data interweave successively, chnnel coding and relevant modulation operation, obtain the coherent constellations mapping symbols;
The framing module, frame structure and preset pattern according to OFDM are inserted into said difference constellation mapping symbol in the said coherent constellations mapping symbols as pilot data, and constitute the ofdm signal frame, send this ofdm signal frame then.
The present invention also provides a kind of ofdm signal receiving system that utilizes differential data as pilot tone, comprising:
Data extraction module is recovered the OFDM symbol through Fourier transform, and is therefrom extracted difference constellation mapping symbol and coherent constellations mapping symbols;
Additional data recovers module; To difference constellation mapping symbol; Divide computing with the differential data demodulation through the guards escorting prisoners; Differential data symbol after being restored, and the differential data symbol after the said recovery carried out channel-decoding and deinterleaving successively, to recover to be modulated at the additional data on the said difference constellation mapping symbol;
Channel estimation module; The former frame difference constellation mapping symbols after utilization recovers and the accurate differential data symbol of the present frame after the recovery; The difference constellation mapping symbol of the present frame after being restored; And the difference constellation mapping symbol that utilizes the present frame after recovering obtains corresponding channel estimation values of pilot frequency positions as given data; Wherein, the differential data symbol of the accurate differential data symbol of the present frame after the said recovery through the present frame after will recovering carry out hard decision and will recover after additional data interweave successively again and chnnel coding draws afterwards;
Main channel data is recovered module; The channel estimation values of pilot frequency positions that utilization obtains is carried out channel estimating to said coherent constellations mapping symbols; Obtain channel estimation value to the present frame of coherent constellations mapping symbols; And the channel estimation value of current frame carried out being applied to the demodulation of coherent constellations mapping symbols after the reprocessing, obtain the main channel data after the demodulation.
Can find out by above embodiment; Embodiments of the invention use differential data to make channel estimating; Made full use of differential modulation and relevant modulation characteristics separately, increased efficiency of transmission, the system compatible arrowband has been moved receive and the broadband wireless transmission; Help reducing the complexity of existing system, improve spectrum efficiency.
The above only is a preferred implementation of the present invention; Should be pointed out that for those skilled in the art, under the prerequisite that does not break away from know-why of the present invention; Can also make some improvement and retouching, these improvement and retouching also should be regarded as protection scope of the present invention.
Claims (9)
1. an ofdm signal sending method of utilizing differential data as pilot tone is characterized in that, may further comprise the steps:
A1 receives main channel data waiting for transmission and additional data;
A2, to said additional data interweave successively, chnnel coding and differential modulation computing, obtain difference constellation mapping symbol;
A3, to said main channel data interweave successively, chnnel coding and relevant modulation operation, obtain the coherent constellations mapping symbols;
A4, frame structure and preset insertion pattern according to OFDM are inserted into said difference constellation mapping symbol in the said coherent constellations mapping symbols as pilot data, and constitute the ofdm signal frame, send this ofdm signal frame then.
2. the ofdm signal sending method of utilizing differential data as pilot tone as claimed in claim 1 is characterized in that said main channel data and additional data are respectively wideband data and narrow band data, and the two is imported by the outside.
3. the ofdm signal sending method of utilizing differential data as pilot tone as claimed in claim 1 is characterized in that, in said steps A 2, said differential modulation computing is calculus of differences or the calculus of differences between the multiframe between two frames.
4. the ofdm signal sending method of utilizing differential data as pilot tone as claimed in claim 1 is characterized in that, in said steps A 2, and the differential modulation that said differential modulation computing is the phase bit arithmetic and the differential modulation of amplitude computing.
5. the ofdm signal sending method of utilizing differential data as pilot tone as claimed in claim 1; It is characterized in that, in said steps A 4, said difference constellation mapping symbol is inserted in the said coherent constellations mapping symbols as pilot tone; And the step that constitutes the ofdm signal frame is specially: A41; Said difference constellation mapping symbol is carried out inverse Fourier transform, constitute insetion sequence, simultaneously said coherent constellations mapping symbols is carried out inverse Fourier transform; Behind the composition data body said insetion sequence is inserted into the head or the afterbody of said data volume, synthetic TDS-OFDM signal frame; Perhaps A42 carries out inverse Fourier transform after being inserted into said difference constellation mapping symbol in the said coherent constellations mapping symbols discretely, and inserts Cyclic Prefix, obtains the CP-OFDM signal frame; Perhaps A43; Said difference constellation mapping symbol is carried out inverse Fourier transform and inserts Cyclic Prefix, constitute the pilot signal frame, said difference constellation mapping symbol is carried out inverse Fourier transform and inserts Cyclic Prefix; The composition data signal frame, both mix formation ofdm signal frame.
6. an ofdm signal dispensing device that utilizes differential data as pilot tone is characterized in that, comprising:
Data reception module receives main channel data waiting for transmission and additional data;
Difference constellation mapping symbol calculation module, to said additional data interweave successively, chnnel coding and differential modulation computing, obtain difference constellation mapping symbol;
Coherent constellations mapping symbols computing module, to said main channel data interweave successively, chnnel coding and relevant modulation operation, obtain the coherent constellations mapping symbols;
The framing module, frame structure and preset insertion pattern according to OFDM are inserted into said difference constellation mapping symbol in the said coherent constellations mapping symbols as pilot data, and constitute the ofdm signal frame, send this ofdm signal frame then.
7. an ofdm signal method of reseptance that utilizes differential data as pilot tone is characterized in that, may further comprise the steps:
B1 recovers the OFDM symbol through Fourier transform, and therefrom extracts difference constellation mapping symbol and coherent constellations mapping symbols;
B2; To difference constellation mapping symbol, divide computing with the differential data demodulation through the guards escorting prisoners, the differential data symbol after being restored; And the differential data symbol after the said recovery carried out channel-decoding and deinterleaving successively, to recover to be modulated at the additional data on the said difference constellation mapping symbol;
B3; The former frame difference constellation mapping symbols after utilization recovers and the accurate differential data symbol of the present frame after the recovery; The difference constellation mapping symbol of the present frame after being restored; And the difference constellation mapping symbol that utilizes the present frame after recovering obtains corresponding channel estimation values of pilot frequency positions as given data; Wherein, the differential data symbol of the accurate differential data symbol of the present frame after the said recovery through the present frame after will recovering carry out hard decision and will recover after additional data interweave successively again and chnnel coding draws afterwards;
B4; The channel estimation values of pilot frequency positions that utilization obtains is carried out channel estimating to said coherent constellations mapping symbols; Obtain channel estimation value to the present frame of coherent constellations mapping symbols; And the channel estimation value of current frame carried out being applied to the demodulation of coherent constellations mapping symbols after the reprocessing, obtain the data after the demodulation.
8. the ofdm signal method of reseptance that utilizes differential data as pilot tone as claimed in claim 7 is characterized in that, it is that guards escorting prisoners between two frames divides the associating guards escorting prisoners between computing or the multiframe to divide computing that said guards escorting prisoners divides computing.
9. an ofdm signal receiving system that utilizes differential data as pilot tone is characterized in that, comprising:
Data extraction module is recovered the OFDM symbol through Fourier transform, and is therefrom extracted difference constellation mapping symbol and coherent constellations mapping symbols;
Additional data recovers module; To difference constellation mapping symbol; Divide computing with the differential data demodulation through the guards escorting prisoners; Differential data symbol after being restored, and the differential data symbol after the said recovery carried out channel-decoding and deinterleaving successively, to recover to be modulated at the additional data on the said difference constellation mapping symbol;
Channel estimation module; The former frame difference constellation mapping symbols after utilization recovers and the accurate differential data symbol of the present frame after the recovery; The difference constellation mapping symbol of the present frame after being restored; And the difference constellation mapping symbol that utilizes the present frame after recovering obtains corresponding channel estimation values of pilot frequency positions as given data; Wherein, the differential data symbol of the accurate differential data symbol of the present frame after the said recovery through the present frame after will recovering carry out hard decision and will recover after additional data interweave successively again and chnnel coding draws afterwards;
Main channel data is recovered module; The channel estimation values of pilot frequency positions that utilization obtains is carried out channel estimating to said coherent constellations mapping symbols; Obtain channel estimation value to the present frame of coherent constellations mapping symbols; And the channel estimation value of current frame carried out being applied to the demodulation of coherent constellations mapping symbols after the reprocessing, obtain the main channel data after the demodulation.
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| KR101777215B1 (en) * | 2015-02-13 | 2017-09-11 | 삼성전자주식회사 | Transmitting apparatus and receiving apparatus and controlling method thereof |
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| CN101601244A (en) * | 2006-11-24 | 2009-12-09 | 法国电信公司 | Use the transmission/reception methods and the module of the multiple-carrier multiple-antenna system of training sequence |
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