CN101677309B - Launcher, interleaver and interleaving method - Google Patents
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Abstract
The invention relates to a launcher which comprises a device for dividing a usable frequency band into a plurality of sub-frequency bands, a device for mapping constellation symbol sequences as OFDM cell sequences, a device for interweaving the OFDM cell sequences, and a device for mapping each OFDM cell to one of the sub-frequency bands, wherein each sub-frequency band comprises an adjacent frequency, each OFDM cell is defined as a constellation symbol group, afterwards, constellation symbols can only be processed in the form of group.
Description
Technical field
The present invention relates to field of wireless communications systems, relate in particular to a kind of improvement deinterleaving method for OFDM (OFDM) communication.
Background technology
OFDM (OFDM) is a kind of transmission technology that realizes transmission high data rate on very noisy channel with relatively low complexity, and is applied in digital audio broadcasting (DAB) and digital video broadcasting (DVB).OFDM has some good character, the robustness of high spectrum efficiency and channel scattering for example, and therefore, it will probably be used for the following broadband application such as digital mobile radio communication.
In brief, in ofdm system, data waiting for transmission are modulated to be spread on a large amount of carrier waves, and is proportional to carrier number and is therefore reduced by the data rate that each carrier wave in these carrier waves passes on.That these carrier waves have is equal, accurately selected frequency interval, and the frequency band of subcarrier be not separately but overlapping.By using IFFT (inverse fast Fourier transform) conduct modulation, the interval of chooser carrier wave by this way: for the signal of certain subcarrier-modulated, can correctly recover from the signal that receives, and all other signals are zero.Carry out the selection in carrier spacing to guarantee its orthogonality, this is also the origin of OFDM.
Design suitable ofdm system and the scatter fading channel is transformed into the flat fading channel that need not advanced time-domain equalizer.This provides obvious enforcement advantage, because do not need equalizer also therefore to reduce the complexity of transceiver, but this has also caused system can not obtain the frequency diversity that channel provides.Opposite with carrier wave communication system (for carrier wave communication system, but the usable frequency diversity in the good equalizer bid of design), ofdm system must reach the more high-order diversity performance that wireless environment provides by means of specific method.
This is very known in the document of relevant OFDM, and an acceptable method of bid frequency diversity is to use coding (for example convolution code or turbo code), and its modulated spread spectrum of output bit is on all subcarriers.As S.K.Wilson and J.M.Cioffi ' A comparison of a single-carriersystem using a DFE and a coded OFDM system in a broadcast Rayleigh-fadingchannel ' (information theory international symposium (ISIT), September nineteen ninety-five) as described in, as long as the order of diversity of coding is greater than the frequency diversity tuple of channel, the method just can be caught the usable frequency diversity.
Because OFDM has created one group of flat fading channel effectively, therefore designing any technology of improving the communication performance on flat fading channel can be applied on OFDM.
A kind of method of improving the diversity performance of (namely not having redundancy to be added on the message bit stream) signal of communication of usually not encoding in flat fading channel is: increase the order of diversity of modulation symbol, namely increase so-called modulation diversity.At " Signal Space Diversity:A Power-and Bandwidth-Efficient DiversityTechnique for the Rayleigh Fading Channel " (IEEE information theory journal, the 44th volume, the 4th phase, in July, 1998, Joseph Boutros and Emanuele Viterbo) in analyzed this alternative diversity technique.By some rotation is applied on traditional signal constellation (in digital modulation), so that the mode that any two constellation point obtain the different component of maximum quantity increases modulation diversity.Therefore the decline of the signal phasor that has transmitted is dispersed on many components and has realized better noise effect protection, because those components are subject to different influence of fading, and does not have two somes meetings simultaneously destroyed.Shown in this document: when modulation diversity was larger, the QAM of multidimensional (quadrature amplitude modulation) constellation became insensitive to declining.
; above-mentioned document has been supposed the desirable any special characteristics that interweaves and do not utilize ofdm system; particularly do not utilize any characteristic (in multi-user OFDM system, in each OFDM mark space, the part of total usable spectrum is only used at alone family) of multi-user OFDM system.The shortcoming of modulation diversity is: in the situation that imperfect interweaving, performance gain may be inappreciable.
At Dennis L.Goeckel and Ganesh Ananthaswamy " On the Design ofMultidimensional Signal Sets for OFDM Systems " (ieee communication journal, the 50th volume, the 3rd phase, in March, 2002) further obtain the prior art of being correlated with in.In this document, for the OFDM transmission system of routine has been developed " merge several subcarriers, send the symbol in a multi-dimensional constellation ".Advised a kind of coding modulation technique: picks symbols from the set of multidimensional complex signal, then the selected subcarrier-modulated of each Wesy's ofdm system of selected symbol, obtain diversity gain like this.In this document, in each OFDM mark space, the transmission of the constellation symbol component subcarrier-modulated of disperseing.This method has some shortcomings.At first, this document does not have to describe the application to multi-user system.Even it can be applied in multi-user system, due to the dispersing characteristic of subcarrier, also cause being difficult to carry out channel estimating.Secondly, due to specific, off-gauge, irrotational constellation structures, make detection more complicated; The 3rd, the performance in Gaussian channel is not best.
On frequency selective fading channels, the diversity that typical uncoded ofdm system is realized obviously is less than the uncoded single-carrier system that uses suitable channel equalizer.A kind of method of reappearing the ofdm system frequency diversity is to use to encode/interweave on subcarrier, other method is to adopt high diversity symbol constellation (the limited real-valued set of vectors that the bit after coding shines upon), and the component that this high diversity symbol constellation has usually said signal space diversity or modulation diversity interweaves.The advantage of first method is: the diversity of bringing after code redundancy has produced additional performance gain, but cost is the increase of bandwidth.The advantage of second method is: needn't increase any bandwidth (there is no redundancy) and just can obtain frequency diversity., two methods all require suitable interleaving scheme respectively symbol and sign component decorrelation.
Because an interleaving scheme may produce than the obvious worse performance of another interleaving scheme, so desirable OFDM interleaving scheme that is to provide, this scheme is optimized the diversity performance in the ofdm system of all codings, the ofdm system of all codings comprises, the ofdm system that utilizes the ofdm system of redundancy encoding (such as convolution code) and utilize nonredundancy coding (such as modulation diversity).
Further, another purpose is: in the situation that multi-user OFDM, all users in system can both obtain diversity gain.
Therefore, need a kind of OFDM deinterleaving method of optimizing the diversity performance of ofdm system.
Summary of the invention
The objective of the invention is to provide a kind of deinterleaving method in ofdm system, the method is used in the diversity performance optimization of the deversity scheme that creates frequency diversity.
Further aim of the present invention is that all users for ofdm system provide diversity gain.
A further object of the present invention is: compare with known multi-user OFDM system, higher frequency diversity is provided and does not need to increase bandwidth.Modulation diversity does not increase any redundancy to data flow, and can therefore obtain diversity performance gain when keeping data rate.
According to a first aspect of the invention, realize these purposes by a kind of deinterleaving method, a kind of transmitter and a kind of OFDM wireless communication system for the signal communication between at least one transmitter and receiver that is applied in ofdm system in ofdm system.
According to the present invention, a kind of method interweave of being used in ofdm system is provided, wherein said method has been utilized the two-dimensional time-frequency structure of ofdm system.The method comprises the steps: available band is divided into several sub-bands, and every sub-frequency bands includes only necessary side frequency; To the OFDM unit sequence, wherein, defining an OFDM unit is one group of constellation symbol the constellation symbol sequence mapping, and after this step, constellation symbol is only processed in the mode of prescription formula or OFDM unit; The OFDM unit sequence that interweaves, wherein, each OFDM unit can be mapped on one of described sub-band.Preferably, for real part and the imaginary part of OFDM unit, carry out described interweaving respectively, discretely.
According to one embodiment of present invention, the step that available OFDM frequency bandwidth is divided into several sub-bands comprises: the sub-band that frequency band division is become equal sizes.This feature provides simple available resources management.For example, can carry out in a simple manner channel allocation to a large number of users.Therefore the sub-band that uses unequal frequency is also possible, and provides very large design flexibility to the operator of mobile communication system.
According to another embodiment of the present invention, the method is carried out after the constellation mapping step.Therefore, this is additional the interweaving of not carrying out in the prior art.This adds the step that interweaves, and has utilized the T/F dependency structure of ofdm system, and additional diversity is provided.
According to another embodiment of the present invention, the step of mapped constellation symbol sebolic addressing comprises: after the interweaving of the rotation of constellation symbol and constellation symbol component, constellation symbol mapped to the OFDM unit.According to this feature, carry out additional interweaving after the interweaving of the component of constellation symbol, thereby additional diversity is provided.
According to another embodiment of the present invention, the step that interweaves is time and the frequency map of described OFDM unit sequence, wherein, distributes to unique time and frequency band in the Transmission Time Interval that each OFDM unit can use and available frequency spectrum.By means of this, the special time-frequency dependence of OFDM flat fading channel is considered, and has obtained the frequency diversity of channel-attach.
According to another embodiment of the present invention, the mapping mode that uses is randomized T/F mapping.Can find out that this Random Maps mode provides good diversity performance, but can make otherwise too.For example, for different users, only may use mapping modes different on time or frequency.
The invention still further relates to a kind of transmitter, this transmitter comprises for the device of carrying out this deinterleaving method.The invention still further relates to a kind of communication system that comprises at least one described transmitter.
Above-mentioned attendant advantages is realized by transmitter and the system that the embodiment of the present invention provides respectively.
When the present invention being applied to turbo coded system (or other method of use soft-decision), improved the soft bit of presenting to the first order of iterative decoder.Therefore, decoded bit has the mistake probability lower than the system that does not obtain this diversity.
And when being applied to multi-user system, all users in system will obtain similar diversity by means of the present invention and improve.
The present invention also provides a kind of method, and it can be easy to merge with existing OFDM standard, thereby makes it become very attractive alternative.
Description of drawings
Fig. 1 shows the method for prior art.
Fig. 2 shows the basis of ofdm system.
Fig. 3 shows according to the legend of the afterbody of OFDM transmitter base band level of the present invention, OFDM unit and the grouping of frequency band.
Fig. 4 shows typical downlink transmitter handle link.
Fig. 5 shows the final stage according to OFDM transmitter processes link of the present invention.
Fig. 6 a-d shows the T/F mapping mode exemplary for the present invention.
Fig. 7-8 show some experimental results.
Embodiment
As what explain in introduction part, OFDM has created one group of flat fading channel effectively, and any technology that is designed to improve the communication performance on flat fading channel can be applied on OFDM., the certain relevant structure of OFDM flat fading channel provides the special chance of improving, and this point is recognized by inventor of the present invention.Specifically, the multicarrier system such as OFDM has two-dimensional structure (time dimension and frequency dimension), and this structure provides the condition of diversity gain from frequency dependence and time correlation respectively for the designer.
In multi-user OFDM system, the part of total usable spectrum is only used at alone family in each OFDM mark space.The chance that it provides additional T/F to interweave for example combines interweaving of existing data bit with constellation mapping, also can obtain the potential frequency diversity gain of channel.
As previous description, document " SignalSpace Diversity:A Power-and Bandwidth-Efficient Diversity Technique for theRayleigh Fading Channel " (IEEE information theory journal at Joseph Boutros and Emanuele Viterbo, the 44th volume, the 4th phase, in July, 1998) provide a method that realizes modulation diversity in.As previous explanation, the key that increases modulation diversity is so that the mode that any two constellation point obtain different component as much as possible is applied to some rotation on traditional signal constellation (in digital modulation).Such rotary manipulation will not change the performance on AWGN (additive white Gaussian noise) channel, but will improve the performance on smooth Rayleigh (Rayleigh) fading channel.The basic necessary condition of this type of improved performance is: the real part of signal transmission and imaginary part are incoherent.In order to create this necessary condition, introduce so-called component interleaver in one of signal in orthogonal branch.Component interleaver has been destroyed the correlation between homophase and quadrature signal component, only has one-component experience deep fading during the institute of the constellation symbol of consequently transmitting is important.
The method of above-mentioned prior art as shown in Figure 1.Inventor of the present invention has realized that this method that can adjust and realize completing according to the present invention in ofdm system.Fig. 2 has illustrated that the FFT in the ofdm system (fast Fourier transform) and Cyclic Prefix are for conversion into the flat Rayleigh fading channel to scatter channel, and inventor of the present invention has realized that therefore modulation diversity is applicable to ofdm system.Correspondingly, the present invention relates to a kind of method, the method is compared with the gain of modulation diversity described in document, at the interval of time and frequency, further amplifies diversity gain by reasonable time-frequency interlacing in multi-user OFDM based on the OFDM unit.The T/F interleaver of OFDM unit makes every a pair of OFDM unit uncorrelated as far as possible in frequency-domain and time-domain to the constellation symbol that receives.
With reference now to Fig. 3,, with some essential characteristics of description OFDM transmitter and according to feature of the present invention.Here, definition OFDM unit is the one group of constellation symbol that is mapped to one of interior some equal sub-bands of total usable spectrum.According to the present invention, preferably, total frequency spectrum is divided into equal sub-band.The frequency sub-bands that equates is preferred, because help resource management (for example more easily distributing available resources), but the sub-band that is divided into non-equal frequencies is also possible.The OFDM unit is fed in inverse fast Fourier transform (IFFT) processor, at this, completes pulse shaping and modulation.In receiver, utilize fast Fourier transform to complete opposite operation, this is conventionally known to one of skill in the art.Then signal is fed to and string location (P/S), and at this, N parallel data stream is combined to be a data flow.After this, add Cyclic Prefix.
With reference now to Fig. 4,, Fig. 4 has described the exemplary process of being completed by transmitter on the down link of mobile communication system.At first bit block is carried out cyclic redundancy check (CRC) (CRC), then for example encode with convolutional encoding or turbo.Then, consequent bit block is perforated and is interleaved and is mapped on constellation of complex.After this one-level, a N is just arranged here
sThe constellation symbol of individual complex values.Detail with reference third generation partnership project 3GPP TS 25.212 V5.2.0 (2002-09) (for example the 4.2nd chapter).
One embodiment of the present of invention are relevant with the decline of transmitter processes link: N
sThe mapping (by subcarrier pointer and OFDM mark space pointer characterized) of individual constellation symbol to the OFDM physical resource, perhaps physical channel mapping., can carry out in the other places in transmission link according to deinterleaving method of the present invention.Finally, N
sEach symbol in individual constellation symbol is mapped as the part (sub-carrier frequency) of OFDM mark space and FFT by this OFDM physical channel.The present invention is subdivided into three phases to the universal architecture of OFDM physical channel mapping, as what describe with reference to Fig. 4.
With compare (" On the Design of Multidimensional Signal Sets for OFDM Systems ") with reference to the top art methods of transmitting the constellation symbol component with the subcarrier of dispersion in each OFDM mark space, the present invention divides into groups to adjacent subcarrier.Although most of sub-band frequency is adjacent one another are, some frequencies that depart from can form the part of sub-band.These frequencies that depart from will be for non-customer service, for example pilot signal.This class of subcarrier is assembled by providing better channel estimating condition to simplify channel estimating.The OFDM channel estimation methods utilizes the strong correlation of the channel fading between adjacent sub-carrier usually.Therefore, the decay of a known frequency, this known decay or decline that can be used to estimate side frequency.Therefore, reduce the needs of pilot signal transmitted (that is, known signal sequence), do not needed for each frequency sends a pilot signal, and can save thus the resource of shortage and the data rate of raising user data.
Therefore two conflicting aspects are arranged: the interval between hope group and group is large as far as possible on the one hand, in order to realize diversity; Interval between hope group on the other hand and group is as far as possible little, because this will help channel estimating.The present invention has conciliate this two aspects, because available band is divided into several sub-bands (that is, basically only having adjacent subcarrier group to be aggregated) and modulation diversity (by reasonable time-frequency interlacing) is provided simultaneously.
As explained before, the T/F interleaver of OFDM unit makes every a pair of OFDM unit uncorrelated as far as possible in frequency-domain and time-domain to the constellation symbol that receives.Especially, and with reference to figure 4, OFDM T/F interleaver according to the present invention was comprised of the following three basic stage:
1. the constellation symbol sequence is to the mapping of OFDM unit sequence.After this one-phase, constellation symbol is only processed in the mode of the mode of group or OFDM unit.Specifically, after the interweaving of the rotation of constellation symbol and constellation symbol component, complete the mapping of constellation symbol to the OFDM unit.
2.OFDM the unit interweaves.The OFDM unit sequence is interleaved.This is that one additional (when being used in described example) interweaves, and it is not performed in the prior art, and preferably, interweaves respectively for real part and the imaginary part of OFDM unit.
3.OFDM the T/F of unit sequence mapping (i.e. one group of constellation symbol).Wherein, each OFDM unit is assigned with unique time and the frequency band in available Transmission Time Interval and available frequency spectrum.
At first, after constellation mapping, consequent N
sIndividual constellation symbol is mapped to N
OFDMOn individual OFDM unit.Each OFDM unit is one group of constellation symbol just here, and all OFDM unit comprises the constellation symbol of equal amount usually.The grouping constellation symbol so that each group can be mapped on specific frequency sub-bands.
Secondly, by considering 2 dimension correlation properties of wireless channel, the OFDM unit interleaver is used for optimizing the performance (previously appearing in transmitter chain, referring to Fig. 3) of bit interleaver.The OFDM unit interleaver can be by N
OFDMThe permutation vector I of individual continuous OFDM unit describes.By permutation vector I=[1 2 3...N are set
OFDM], can make the OFDM unit interleaver apparent.
According to preferred embodiment, shine upon respectively real part and the imaginary part of OFDM unit.Obtain thus better diversity gain, and resist the noise effect that is present in system more efficiently, because suppose that these two components do not experience the deep fading.The real part of signal is mapped on a particular sub-band and imaginary part is mapped on other sub-band.
At last, the OFDM unit sequence that is interleaved is mapped on physical channel.For this purpose, as mentioned above, whole available OFDM frequency band is divided into N
BIndividual frequency sub-bands.Single physical channel is at N
Sym_intOnly use 1/N in the individual OFDM unit interval duration
BTotal available aggregate resources, mean: may have up to N
BIndividual concurrent user or have up to N for unique user
BIndividual parallel physical channel has been realized the data rate that is exceedingly fast of unique user.
The size of OFDM unit (being number of constellation symbols) is such: so that each frequency sub-bands comprises an OFDM unit in each OFDM mark space.This refers to can transmit in each OFDM mark space at most N
BIndividual parallel OFDM unit.
When carrying out T/F (T-F) mapping of phase III, each user can specify specific pattern, referring to Fig. 6 a-d.In Fig. 6 a-d, illustrated to be used for the different mode of phase III, and four different patterns exemplary, N have been shown
B=15 and N
Sym_int=12 and N
OFDM=12.Attention: N
OFDM=N
Sym_intIt must not this situation.If these parameters are different, N
BN
Sym_intIndividual resource can be fit to surpass N
BThe N of individual OFDM unit
OFDMStream.
In Fig. 6 d, randomized T-F mapping D is a preferred embodiment, and show ITU-channel VA120 (the vehicle A of 120km/h with regard to bit error rate and frame error rate aspect, details is referring to 3GPP TR25.890 V1.0.0,2002-05) and PB3 (the pedestrian B of 3km/h, details is referring to 3GPP TR 25.890V1.0.0,2002-05) the optimum performance A-D of T-F in some channel circumstance as shown in Fig. 6 a-d mapping.Fig. 7 shows some test results, and the performance of the T-F mapping of Fig. 6 a-d has been described.In Fig. 7, the bit error rate (BER) when having drawn the mapping as shown in Fig. 6 a-d of channel circumstance (vehicle A, 120km/h) of ITU regulation.In Fig. 6 d, randomized T-F mapping D is preferred embodiment, and shows as the optimum performance in certain channel circumstance that can see in Fig. 8.In Fig. 8, the bit error rate (BER) when having drawn again the mapping as shown in Fig. 6 d of channel circumstance (vehicle A, 120km/h) of ITU regulation.In coding and uncoded situation and modulation diversity is arranged and there is no the situation of modulation diversity and test.Carry out iteration eight times in the turbo decoder.Just as can be seen, greatly improved performance according to modulation diversity method of the present invention.
The mapping of the T/F of OFDM unit is characterized by two parameters of each OFDM unit: an indication OFDM symbol time interval, the frequency sub-bands that indication is selected.These parameters can concentrate on the scope of being contained in { 1, N
OFDMIn the T vector of OFDM mark space index be contained in scope { 1, N
BIn the F vector of each corresponding sub-band index in OFDM unit in.For k input of OFDM unit, its T-F mapping is determined by k corresponding T and the F value in position.
The mapping of using will produce optimally diversified performance in any channel circumstance.Should be like this: make every a pair of OFDM unit uncorrelated as far as possible in frequency-domain and time-domain to the constellation symbol that receives.
A typical way of division signals component is that they are divided into respectively real part and imaginary part, perhaps equally, they is divided into homophase and quadrature component.When the method according to this invention was improved performance in conjunction with modulation diversity, real part and imaginary part respectively importantly interweaved.When the method according to this invention is generally used for improving the performance of ofdm system of coding, can complete interweaving of OFDM unit sequence according to other mode.
Can complete mapping by means of trial-and-error method (trial-and-error) in one embodiment, perhaps can complete it according to the selection of channel in another embodiment.
As well known in the art, soft-decision decoding has brought stronger certainty to decoding, because considered the symbol of reception signal (hard decision) and the tolerance of amplitude.Data are modulated onto on several carrier waves in ofdm system, and different carrier waves will have different signal to noise ratios and will therefore experience different declines.Preferably, real part and imaginary part because the method according to this invention interweaves on different sub-bands respectively, the probability all lost of two components is very little, perhaps changes a kind of saying, and the probability that receives at least one component that does not worsen is larger.Therefore, when the present invention being applied to the system of turbo coding (perhaps using other system of soft-decision), improved the soft bit of presenting to first order iterative decoder.Therefore, decoded bit will have the mistake probability lower than the system that does not obtain this diversity.
The present invention can be used in the high speed descending sharing channel (HS-DSCH) based on third generation cellular system in the transmission system of multi-user OFDM.
The invention provides a kind of method that can be easy to merge with existing standard or be easy to be increased on existing standard, ETSI 3GPP TS 25 212 V5.2.0 (2009-09) for example, 3GPP TSG RAN: multiplexed and chnnel coding (FDD) (version 5).Therefore the present invention is very attractive and has the alternative of practicality.
The present invention combines preferred embodiment and is described.Clearly, consider foregoing description, a lot of selections, modification, variation and use will be apparent for a person skilled in the art.For example, described according to deinterleaving method of the present invention in conjunction with the channel mapping level., the present invention is not restricted to this, can be used for first (and may be unique) according to deinterleaving method of the present invention and interweave, perhaps as the step that interweaves in other place in chain.Those skilled in the art can realize completing corresponding deinterleaving in receiver.
Claims (15)
1. transmitter, it is characterized in that: described transmitter comprises:
Be used for available band is divided into the device of several sub-bands, every sub-frequency bands comprises adjacent frequency;
Being used for being the constellation symbol sequence mapping device of OFDM unit sequence, and wherein, define an OFDM unit is one group of constellation symbol, and after this, constellation symbol is only processed in the mode of organizing;
Be used for the interweaving device of described OFDM unit sequence, wherein, each described OFDM unit is mapped at least one described sub-band.
2. transmitter as claimed in claim 1 is characterized in that: describedly available band is divided into several sub-bands comprises: the sub-band that frequency band division is become equal sizes.
3. transmitter as claimed in claim 1 is characterized in that: describedly available band is divided into several sub-bands comprises: the sub-band that frequency band division is become non-equal sizes.
4. as any one described transmitter of claim 1-3, it is characterized in that: the described OFDM of interweaving unit sequence comprises: interleaved signal component respectively.
5. transmitter as claimed in claim 4, it is characterized in that: the described OFDM of interweaving unit sequence comprises: real part and imaginary part discretely interweave respectively.
6. as any one described transmitter of claim 1-3, it is characterized in that: described is the constellation symbol sequence mapping that the OFDM unit sequence comprises: after the rotation constellation symbol constellation symbol mapped to the OFDM unit.
7. as any one described transmitter of claim 1-3, it is characterized in that: described interweaving is that the OFDM unit sequence is mapped on time and frequency resource, wherein, be unique time and frequency band in each OFDM unit distribution available transmission time interval and usable spectrum.
8. as any one described transmitter of claim 1-3, it is characterized in that: the mapped mode that each OFDM unit that uses is mapped at least one described sub-band is randomized T/F mapping.
9. as any one described transmitter of claim 1-3, it is characterized in that: this transmitter is used for multi-user environment.
10. an OFDM T/F interleaver, is characterized in that, comprising:
Be used for the device of constellation symbol sequence mapping to the OFDM unit sequence, wherein, define an OFDM unit is one group of constellation symbol, and after this, constellation symbol is processed in the mode of organizing;
Device for the described OFDM unit sequence that interweaves; With
Be used for the time of described OFDM unit sequence and the device of frequency map, time and the frequency map of described OFDM unit sequence comprise:
For distributing unique time and frequency band in available Transmission Time Interval and available frequency spectrum in each OFDM unit in described OFDM unit sequence.
11. interleaver as claimed in claim 10 is characterized in that, described OFDM unit sequence is mapped on physical channel.
12. an OFDM T/F interleaver is characterized in that, comprising:
Be used for the device of constellation symbol sequence mapping to the OFDM unit sequence, wherein, define an OFDM unit is one group of constellation symbol, and after this, constellation symbol is processed in the mode of organizing;
Device for the described OFDM unit sequence that interweaves; With
Be used for the time of described OFDM unit sequence and the device of frequency map, the T/F mapping of each OFDM unit in described OFDM unit sequence is characterized by two parameters of each OFDM unit: an indication OFDM symbol time interval, the frequency sub-bands that indication is selected.
13. an OFDM T/F deinterleaving method is characterized in that, comprising:
To the OFDM unit sequence, wherein, defining an OFDM unit is one group of constellation symbol with the constellation symbol sequence mapping, and after this, constellation symbol is only processed in the mode of group;
Described OFDM unit sequence interweaves; With
The time of described OFDM unit sequence and frequency map, time and the frequency map of described OFDM unit sequence comprise:
For distributing unique time and frequency band in available Transmission Time Interval and available frequency spectrum in each OFDM unit in described OFDM unit sequence.
14. deinterleaving method as claimed in claim 13 is characterized in that, described OFDM unit sequence is mapped on physical channel.
15. an OFDM T/F deinterleaving method is characterized in that, comprising:
To the OFDM unit sequence, wherein, defining an OFDM unit is one group of constellation symbol with the constellation symbol sequence mapping, and after this, constellation symbol is only processed in the mode of group;
Described OFDM unit sequence interweaves; With
The time of described OFDM unit sequence and frequency map, the T/F mapping of each OFDM unit in described OFDM unit sequence is characterized by two parameters of each OFDM unit: an indication OFDM symbol time interval, the frequency sub-bands that indication is selected.
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| CN1359569A (en) * | 1999-08-19 | 2002-07-17 | 因特隆公司 | Robust transmission mode |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1995034967A1 (en) * | 1994-06-16 | 1995-12-21 | France Telecom | Ofdm signal organized so as to simplify reception |
| CN1213472A (en) * | 1996-03-14 | 1999-04-07 | 德国电信股份有限公司 | Process and system for OFDM multi-carrier transmission of digital radio signals |
| CN1359569A (en) * | 1999-08-19 | 2002-07-17 | 因特隆公司 | Robust transmission mode |
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