CN1801680A - Pilot multiplex method based on interlaced FDMA and its device - Google Patents

Abstract

The invention discloses a pilot-frequency multiplexing method based on interlaced FDMA to treat at least two pilot-frequency symbols time-division with user data symbol in one estimated channel period, which comprises: setting sub-carrier density taken by user in data symbol period larger than the one in pilot-frequency symbol period; grouping user; crossing to take pilot-frequency sub-carrier one another in pilot-frequency symbol period for every user of one group. This invention can obtain well interpolation treatment effect.

Description

Pilot multiplex method and device thereof based on interlaced FDMA

Technical field

The present invention relates to wireless communication technology, relate in particular to a kind of pilot multiplex method and device thereof based on interlaced FDMA (IFDMA, interleaved frequency division multiple access).

Background technology

In recent years, multi-transceiver technology becomes the hot spot technology of broadband wireless communications, and its basic thought is that a bandwidth carrier is divided into a plurality of subcarriers, and on a plurality of subcarriers that mark off the parallel transmission data.Usually the width of subcarrier is less than the coherence bandwidth of channel, on frequency-selective channel, the decline of each subcarrier is a flat fading just, can reduce crosstalking between data symbol like this, and do not need complicated channel equalization, be suitable for the transfer of data of two-forty.Multi-transceiver technology can use frequency domain channel estimation technique and frequency-domain equalization technology usually; some single-carrier systems also can be by carrying out Fourier transform (FFT at receiving terminal; Fourier Transformation); the system of single-carrier system equivalence for being made of a plurality of parallel subcarriers, frequency domain channel is estimated and frequency domain equalization is handled to carry out.

Frequency domain channel estimates to adopt usually the coherent demodulation method based on supplementary, some known frequency pilot sign or training sequences are inserted in some fixed position that sends signal at transmitting terminal, and utilize these pilot signals to carry out frequency domain channel according to certain algorithm at receiving terminal and estimate.Wherein channel is carried out frequency domain and estimate, be equivalent to system and have time-frequency two-dimensional structure (being time domain and frequency domain), the frequency pilot sign design of therefore adopting here will be considered the time-frequency two-dimensional correlation properties of channel as far as possible.Wherein as long as frequency pilot sign is compared enough little with the correlation time of channel with the channel coherence bandwidth with the interval on the frequency direction in the time, just can estimate the channel transfer function of the pilot frequency symbol position that inserts preferably at receiving terminal, and then adopt the method for two-dimensional interpolation to estimate that all insert the channel transfer function of pilot frequency symbol positions.Therefore the design of the frequency pilot sign that inserts becomes a key issue day by day in adopting the system that frequency domain channel is estimated and frequency domain equalization is handled.

At present, in the up link of wireless communication system, the peak-to-average force ratio of transmitting power is a very important problem, and it will directly have influence on the validity and the power consumption characteristic of user terminal power amplifier.Existing interlaced FDMA (IFDMA, interleaved frequency division multiple access) technology by carry out the carrying of signal on time domain waveform, makes that the peak-to-average force ratio of transmitting power is lower; Simultaneously, the running time-frequency resource that takies between the different user also mutually disjoints, thereby can guarantee the interference reduction between the different user in the sub-district.IFDMA can handle by time domain and realize, also can handle by frequency domain and realize, the mode that its IFDMA uses frequency domain to realize is called DFT-S-OFDMA, and these two kinds of implementations can both obtain the lower time domain waveform of transmitting power peak-to-average force ratio.The difference of these two kinds of implementations is that wherein IFDMA uses time domain to handle when realizing to sending the processing of data, is to repeat to realize pectination spectrum on the frequency domain by time domain; And IFDMA uses frequency domain to handle when realizing, then is directly to construct the pectination spectrum according to frequency domain character, is processed into time domain waveform by reverse fast fourier transform (IFFT, Inverse Fast Fourier Transformation) then.Explanation uses time domain processing procedure and frequency domain processing procedure to realize the implementation procedure of IFDMA respectively below.

1, time domain is handled implementation procedure

Here suppose Q the data symbol d of a certain user i _q ⁽ⁱ⁾(d _q ⁽ⁱ⁾Can be real number, also can be plural number) form a data block block, wherein each data symbol duration is Ts, this user's a data block block can be expressed as $d^{\left(i\right)}={[d_0^{\left(i\right)},d_1^{\left(i\right)},\·\·\·,d_{Q-1}^{\left(i\right)}]}^T$ (wherein T representing matrix transposition) compresses the data symbol among this data block block now, makes it become chip duration Tc by data symbol duration Ts, and then this data block block is carried out L time repetition, and the data symbol that obtains after the reprocessing is:

Wherein times represents the number of repetition of this data block block, and the data symbol after this reprocessing can further be expressed as:

$c_l^{\left(i\right)}=\frac{1}{L}\·d_{l\mathrm{mod}Q}^{\left(i\right)},$ l＝0，1，...，QL-1。

On frequency axis, be rendered as the spectral shape of one group of pectination like this through the data symbol sequence that obtains after the reprocessing, as shown in Figure 1.

Because each user's data piece block passes through above-mentioned identical processing, so on frequency axis, show as identical pectination spectrum, simultaneously for fear of the phase mutual interference between the multi-user, need interlaced with each other the coming of the spectrum of the pectination between each user so just need be selected one group of phase vectors that the user is specific at this:

$s_l^{\left(i\right)}=\exp \{-j\·l\·{\mathrm{\Φ}}^{\left(i\right)}\},$ l＝0，...，QL-1， ${\mathrm{\Φ}}^{\left(i\right)}=i\·\frac{2\mathrm{\π}}{\mathrm{QL}},$ Wherein S represents user's phase vectors, and Φ represents phase rotation coefficient;

This group phase vectors and above-mentioned data symbol c that obtains with the user that obtains _l ⁽ⁱ⁾Multiply each other by element, the useful data that will obtain the transmission signal of this user i at last partly is:

$x^{\left(i\right)}={[c_0^{\left(i\right)},c_1^{\left(i\right)}{e}^{-\mathrm{j\Φ}\left(i\right)},\·\·\·,c_{\mathrm{QL}-1}^{\left(i\right)}{e}^{-j(\mathrm{QL}-1)\mathrm{\Φ}\left(i\right)}]}^T.$

In actual treatment, also need further to add guard time and disturb to reduce or eliminate between the data symbol that causes owing to the channel multi-path time delay, wherein the guard time that adds requires to satisfy T _Δ＞τ _Max(T wherein _ΔThe guard time value that expression adds, τ _MaxThe maximum multipath delay spread of expression channel); Simultaneously in order to simplify the frequency domain equalization processing procedure of receiving terminal, also to be chosen as and send signal code adding Cyclic Prefix (CP, cyclicprefix), be about to each one section symbol in end that sends signal code and copy to before the original position of this signal code, the transmission signal code length that obtains like this will become T _s+ T _Δ, and receiving terminal was wanted the redundancy of corresponding removal CP part before handling received signal.

Accordingly, a plurality of users' pectination spectrum need be separated at receiving terminal, and merge the data symbol that repeats separately; Also need to introduce frequency-domain equalizer simultaneously and resist the interference ISI between data symbol in the data block that in the wireless transmission process, causes.The maximum users multiplexing number that the IFDMA system that is realized by the time domain processing mode can support will be no more than the number of repetition L of its data block.

2, frequency domain is handled implementation procedure (DFT-S-OFDMA)

Be illustrated in figure 2 as the realization principle schematic of existing DFT-S-OFDMA: transmitting terminal at first carries out discrete Fourier (DFT with the time domain data that sends, Discrete Fourier Transformation) handle, promptly the time domain data to pre-transmission carries out " precoding " operation; Frequency domain data after then DFT being handled carries out the frequency domain windowing process, sends the peak-to-average force ratio (this process is optional) of time domain data in advance with further reduction; Mapping ruler according to the rules is mapped to frequency domain data on the wideer frequency band then, and the frequency domain data after at last mapping being handled carries out reverse fast fourier transform (IFFT), to obtain corresponding time domain waveform.

The committed step of this processing procedure is exactly the mapping processing of frequency domain data, if the equal in length of DFT and IFFT, mapping is exactly one to one so, and DFT handled with the IFFT processing and offset fully this moment, and equivalence is a single carrier link; And if the length of DFT is less than IFFT, so just need to handle, that is: by equally spaced mapping

With obtain with above-mentioned time domain processing mode in data block repeated the identical pectination of the frequency spectrum that forms for L time compose (as shown in Figure 1), each X[m in the wherein above-mentioned matrix] the frequency domain sampling point that obtains through the DFT conversion of expression, be offset by different subcarrier in frequency domain to realize and distinguish different users, equivalence is the user's phase place rotation in the IFDMA system.

Time domain waveform after said process is handled equally need be through increasing the CP operation.

Accordingly, after receiving terminal removed CP, corresponding at first needing carried out the FFT processing to the data of removing after CP handles, and the mapping ruler according to transmitting terminal separates the pectination spectrum of different user then, carry out IDFT through after the equilibrium treatment of frequency domain again, to obtain the time domain data that demodulation process needs.In like manner, the maximum users multiplexing number that can support of the IFDMA system that is realized by the frequency domain processing mode also will be no more than L.

In the IFDMA system that above-mentioned implementation realizes, each user will take a subcarrier system (i.e. one group of broach) at least, and this subcarrier ties up to dispersed and distributed on the whole frequency band, on frequency, when user's signal code is transmitted through actual channel, experience different frequency declines, therefore had the effect of frequency diversity.

In the IFDMA of reality system, need each user when sending upstream data, also to offer the recipient and be used for the frequency pilot sign that frequency domain channel is estimated, adopt the time domain waveform beared information owing to send signal in the IFDMA system, for fear of causing too high peak-to-average force ratio, select frequency pilot sign and data symbol to carry out time-multiplexed mode simultaneously.But the utilization of frequency pilot sign also needs to consider the problem of efficient, and the principle of design is that the resource occupation of frequency pilot sign is no more than 20% for good in all sign resources (frequency pilot sign and data symbol sum); And in order to follow the tracks of time varying channel, as user's translational speed than under the condition with higher, a Transmission Time Interval (TTI, Transmission Time Interval) is 0.5ms or when longer, the frequency pilot sign that needs a plurality of dispersions among TTI, obviously the frequency pilot sign structure shorter than data symbol is easy to satisfy the requirement of above-mentioned condition: the occupancy that can either guarantee sign resources is lower, can follow the tracks of time varying channel again.In the prior art at present, for the convenience of handling, can suppose frequency pilot sign is set at half length of data symbol, be called half symbol pilot tone, be illustrated in figure 3 as the typical TTI structural representation that adopts half symbol pilot tone, wherein comprised the frequency pilot sign of two weak points among this TTI, and be dispersed between the interior data symbol of a TTI.

With TTI structure shown in Figure 3 is example, and such TTI structure satisfies the requirement in the design, but in actual applications, especially under the multi-access mode in the IFDMA system, half symbol pilot tone mode has been brought other problem again.In Digital Signal Processing, time span has determined the granularity of the numerical frequency on frequency domain, and frequency pilot sign and data symbol are not isometric, and this user's frequency pilot sign is not corresponding with the frequency component of data symbol on frequency domain with causing.That is to say that after through the wireless channel transmission, frequency pilot sign can not directly provide the decline information of all frequency component experience of data symbol, thereby may have influence on the demodulation performance of received signal symbol.Below will specifically set forth the reason that causes this defective:

In Digital Signal Processing, represent the time domain waveform and the frequency domain performance of signal code usually with the FFT/IFFT transfer pair, that is:

$X\left[m\right]=\underset{n=0}{\overset{N-1}{\mathrm{\&Sigma;}}}x\left(n\right)\exp (-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="A20051009258600213.png,A20051009258600221.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}\frac{\mathrm{mn}}{N}),m=\mathrm{0,1},\&CenterDot;\&CenterDot;\&CenterDot;,N-1$

X[m] performance of expression frequency domain, i.e. each subcarrier;

$x\left(n\right)\frac{1}{N}\underset{m=0}{\overset{N-1}{\mathrm{\&Sigma;}}}X\left[m\right]\exp \left(\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="A20051009258600213.png,A20051009258600221.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}\frac{\mathrm{mn}}{N}\right),n=\mathrm{0,1},\&CenterDot;\&CenterDot;\&CenterDot;,N-1$ X (n) represents time domain waveform;

According to top IFDMA technical description, in the time division multiplexing TTI structure of half symbol pilot tone and data symbol, data symbol has different phase rotation coefficients with frequency pilot sign: the phase rotation coefficient of the data division of user i is $\mathrm{\&Phi;}\left(i\right)=i\&CenterDot;\frac{2\mathrm{\&pi;}}{\mathrm{QL}},$ I=0,1 ..., L-1, in order to support the number of users of as much, the phase rotation coefficient of the pilot portion of half symbol lengths is:

${\mathrm{\&Phi;}}^{\&prime;}\left(i\right)=i\&CenterDot;\frac{2\mathrm{\&pi;}}{(Q/2)\&CenterDot;L}=2i\&CenterDot;\frac{2\mathrm{\&pi;}}{Q\&CenterDot;L}=2\mathrm{\&Phi;}\left(i\right),i=\mathrm{0,1},\&CenterDot;\&CenterDot;\&CenterDot;,L-1$

Suppose all that below Q and L are even number, then the repeating part with data symbol and frequency pilot sign writes out respectively, and the transmission signal code that then obtains data division is:

${x_d}^{\left(i\right)}=[c_0^{\left(i\right)},c_1^{\left(i\right)}{e}^{-\mathrm{j\&Phi;}\left(i\right)},\&CenterDot;\&CenterDot;\&CenterDot;,c_{N-1}^{\left(i\right)}{e}^{-j(N-1)\mathrm{\&Phi;}\left(i\right)}{]}^T,$

And the transmission signal code that obtains pilot portion is:

${x_p}^{\left(i\right)}=[c_0^{\left(i\right)},c_1^{\left(i\right)}{e}^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="A20051009258600213.png,A20051009258600221.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&Phi;}\left(i\right)},\&CenterDot;\&CenterDot;\&CenterDot;,c_{N/2-1}^{\left(i\right)}{e}^{-j(N/2-1)2\mathrm{\&Phi;}\left(i\right)}{]}^T,$

Respectively the time-domain signal of the data symbol that obtains and frequency pilot sign is carried out FFT and transforms to frequency domain, then obtain frequency component separately respectively:

$X_d\left[m\right]=\underset{n=0}{\overset{\mathrm{QL}-1}{\mathrm{\&Sigma;}}}{c}_n^{\left(i\right)}\exp (-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="A20051009258600213.png,A20051009258600221.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}\frac{i\&CenterDot;n}{\mathrm{QL}})\exp (-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="A20051009258600213.png,A20051009258600221.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}\frac{\mathrm{mn}}{\mathrm{QL}})=\underset{n=0}{\overset{\mathrm{QL}-1}{\mathrm{\&Sigma;}}}{c}_n^{\left(i\right)}\exp (-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="A20051009258600213.png,A20051009258600221.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}\frac{(m+i)\&CenterDot;n}{\mathrm{QL}})$

m＝0，1，...，QL-1，i＝0，1，...，L-1

$X_p\left[m\right]=\underset{n=0}{\overset{\frac{Q}{2}L-1}{\mathrm{\&Sigma;}}}{c}_n^{\left(i\right)}\exp (-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="A20051009258600213.png,A20051009258600221.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}\frac{2i\&CenterDot;n}{\mathrm{QL}})\exp (-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="A20051009258600213.png,A20051009258600221.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}\frac{2\mathrm{mn}}{\mathrm{QL}})=\underset{n=0}{\overset{\frac{Q}{2}L-1}{\mathrm{\&Sigma;}}}{c}_n^{\left(i\right)}\exp (-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="A20051009258600213.png,A20051009258600221.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}\frac{2(m+i)\&CenterDot;n}{\mathrm{QL}})$

m＝0，1，...，

i＝0，1，...，L-1

Obviously, as above the frequency component that pilot portion contains shown in the formula is half of data division, simultaneously because the length of frequency pilot sign just in time is half of data symbol, the interval that then draws the frequency component of frequency pilot sign just in time is the twice at interval of the frequency component of data symbol, just the density of subcarrier is inequality, specifically as shown in Figure 4.

Handle in order to carry out effective frequency domain equalization at receiving terminal, just need to obtain the channel information of the frequency granularity identical, carry out frequency domain interpolation for this reason and handle with data symbol.Wherein the principle that the frequency domain channel estimated result is carried out interpolation processing is: the interval of supposing two frequencies utilizes its correlation several frequencies in the middle of obtaining in the channel coherence bandwidth.Usually select the FFT interpolation algorithm at present, the frequency domain channel of receiving terminal is estimated and the step of interpolation processing is:

At first with the pilot signal symbols x that receives _p ⁽ⁱ⁾Carry out FFT and transform in the frequency domain, transform length is

Carry out frequency domain channel with known pilot signal transmitted and estimate, obtain Individual frequency;

Then frequency domain channel is estimated that the channel that obtains carries out IFFT and transforms in the time domain, transform length is

And, do the FFT conversion that QL is ordered to the processing of the time-domain signal zero padding after the conversion:

${\stackrel{\&OverBar;}{X}}_p\left[m\right]=\underset{n=0}{\overset{\mathrm{QL}-1}{\mathrm{\&Sigma;}}}{\stackrel{\&OverBar;}{c}}_n^{\left(i\right)}\exp (-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="A20051009258600213.png,A20051009258600221.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}\frac{2i\&CenterDot;n}{\mathrm{QL}})\exp (-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="A20051009258600213.png,A20051009258600221.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}\frac{\mathrm{mn}}{\mathrm{QL}})=\underset{n=0}{\overset{\mathrm{QL}-1}{\mathrm{\&Sigma;}}}{\stackrel{\&OverBar;}{c}}_n^{\left(i\right)}\exp (-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="A20051009258600213.png,A20051009258600221.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}\frac{(m+2i)\&CenterDot;n}{\mathrm{QL}})$

m＝0，1，...，QL-1；i＝0，1，...，L-1

Obtain channel frequency domain response thus with data division equal frequencies granularity;

The last coefficient that just can utilize this channel frequency response that obtains to calculate frequency-domain equalizer is handled thereby the data-signal symbol that receives is carried out frequency domain equalization.

Wherein in multi-user IFDMA system, when the interval of a user's the shared subcarrier of frequency pilot sign was bigger, the effect that can make frequency domain interpolation handle was not ideal enough; And if in a channel estimation period, when the average frequency domain of the subcarrier that frequency pilot sign is shared is smaller at interval, just may obtain reasonable interpolation processing effect.

Summary of the invention

The technical problem to be solved in the present invention is to provide a kind of pilot multiplex method and device thereof based on interlaced FDMA, reducing the interval of the pilot sub-carrier that frequency pilot sign takies on frequency domain, and then obtains interpolation processing effect preferably.

For addressing the above problem, the technical scheme that the present invention proposes is as follows:

A kind of pilot multiplex method based on interlaced FDMA is used in a channel estimation period carrying out pilot frequency multiplexing between the frequency pilot sign of at least two and user data symbol time-division and handles, and comprises step:

The subcarrier density that A, setting user take during each frequency pilot sign greater than the user in the subcarrier density that takies during the data symbol;

B, the user is carried out packet transaction;

C, every group of each interior user staggered pilot sub-carrier that takies each other between each frequency pilot sign.

Preferably, be to be set at time span less than data symbol by time span to realize that data subcarrier density is greater than pilot sub-carrier density in the described steps A with frequency pilot sign.

Preferably, realize that as pilot sub-carrier data subcarrier density is greater than pilot sub-carrier density by selected part subcarrier in data subcarrier in the described steps A.

Preferably, the relation of the data subcarrier position between each user among every group of user is adjacent among the described step B; Or the relation of the data subcarrier position between each user is at random.

Preferably, the implementation procedure of described step C specifically comprises:

C1, every group of each interior user alternately take each pilot sub-carrier according to original sequencing on first frequency pilot sign frequency domain; And

C2, on next frequency pilot sign frequency domain, after the sequencing of each user in this group changed mutually, on frequency domain, alternately take each pilot sub-carrier.

Preferably, on each frequency pilot sign frequency domain, alternately take the pilot sub-carrier that spectrum overlapping is arranged with the data subcarrier of self between described every group of each interior user.

Preferably, the pilot sub-carrier ratio of each CU in every group is identical among the described step C.

A kind of pilot frequency multiplexing device based on interlaced FDMA is used in a channel estimation period carrying out pilot frequency multiplexing between the frequency pilot sign of at least two and user data symbol time-division and handles, and comprising:

Setup unit is set the subcarrier density that the user takies greater than the user in the subcarrier density that takies during the data symbol during each frequency pilot sign;

Grouped element is used for the user is carried out packet transaction;

Multiplexing Unit, each user in every group of being used for described grouped element is told is the staggered pilot sub-carrier that takies each other between each frequency pilot sign that described setup unit is set.

Preferably, described Multiplexing Unit specifically comprises:

Pilot sub-carrier alternately takies subelement, is used for every group of each interior user and alternately takies each pilot sub-carrier according to original sequencing on first frequency pilot sign frequency domain;

The user changes subelement in proper order, is used at next frequency pilot sign frequency domain, and the sequencing of each user in the group is changed processing; Described pilot sub-carrier alternately takies each pilot sub-carrier after alternately taking subelement each user's in group sequencing transposing on this next frequency pilot sign frequency domain.

A kind of pilot multiplex method based on interlaced FDMA is used in a channel estimation period carrying out pilot frequency multiplexing between the frequency pilot sign of at least two and user data symbol time-division and handles, and comprises step:

A. set the pilot sub-carrier density that the user takies greater than the user in the data subcarrier density that takies on the data symbol frequency domain on each frequency pilot sign frequency domain;

B. a selected frequency pilot sign;

C. on described selected frequency pilot sign frequency domain, determine the shared pilot sub-carrier of each user;

D. on other each frequency pilot sign frequency domains, definite shared pilot sub-carrier of each user on the described selected frequency pilot sign frequency domain is carried out the cyclic shift processing of identical shift amount respectively; For different frequency pilot sign frequency domains, shift amount selected when the shared pilot sub-carrier of each user is carried out shifting processing is different.

A kind of pilot frequency multiplexing device based on interlaced FDMA is used in a channel estimation period carrying out pilot frequency multiplexing between the frequency pilot sign of at least two and user data symbol time-division and handles, and comprising:

Setup unit is used to set the pilot sub-carrier density that the user takies greater than the user in the data subcarrier density that takies on the data symbol frequency domain on each frequency pilot sign frequency domain;

Selected unit is used for a selected frequency pilot sign;

The pilot sub-carrier determining unit is determined the shared pilot sub-carrier of each user on the frequency pilot sign frequency domain that is used for selecting in described selected unit;

The shifting processing unit, be used at other each pilot sub-carriers, described pilot sub-carrier determining unit is being selected the cyclic shift processing that the shared pilot sub-carrier of determining on the selected frequency pilot sign frequency domain in unit of each user carries out identical shift amount respectively; For different pilot sub-carriers, the shift amount when the shared pilot sub-carrier of each user is carried out shifting processing is different.

The beneficial effect that the present invention can reach is as follows:

The present invention is by setting the subcarrier density that the user takies greater than the user in the subcarrier density that takies during the data symbol during each frequency pilot sign; The user is carried out packet transaction; Each user in every group is the staggered pilot sub-carrier that takies each other between each frequency pilot sign; Thereby can be implemented in the interlaced FDMA IFDMA system, a plurality of users shared pilot sub-carrier equispaced on the frequency pilot sign frequency domain reduces, can guarantee that promptly each pilot sub-carrier has smaller spacing on the frequency pilot sign frequency domain, and then improve the validity of frequency domain channel estimation and interpolation processing.

Description of drawings

The pectination spectral shape schematic diagram that Fig. 1 presents on frequency axis through the data symbol sequence that obtains after the reprocessing for data block;

Fig. 2 is the realization principle schematic of existing DFT-S-OFDMA;

Fig. 3 is for adopting the typical TTI structural representation of half symbol pilot tone;

Fig. 4 for the frequency component that adopts the data symbol after the half symbol pilot tone at interval and the frequency component of frequency pilot sign concern schematic diagram between at interval;

Fig. 5 is the main realization principle flow chart that the present invention is based on the pilot multiplex method of IFDMA;

Fig. 6 is according to the inventive method principle, is the data symbol that provides of example and the first example multiplex mode schematic diagram of frequency pilot sign with 4 users;

Fig. 7 is for being the data symbol that provides of example and the second example multiplex mode schematic diagram of frequency pilot sign according to the inventive method principle with 4 users;

Fig. 8 is for being the data symbol that provides of example and the 3rd example multiplex mode schematic diagram of frequency pilot sign according to the inventive method principle with 4 users;

Fig. 9 is for being the data symbol that provides of example and the first example multiplex mode schematic diagram of frequency pilot sign according to the inventive method principle with 6 users, 3 pilot tones;

Figure 10 is the main composition structured flowchart that the present invention is based on the pilot frequency multiplexing device of IFDMA;

Figure 11 is another main realization principle flow chart based on the pilot multiplex method of IFDMA of the present invention;

Figure 12 is for being the data symbol that provides of example and the second example multiplex mode schematic diagram of frequency pilot sign according to the inventive method principle with 6 users, 3 pilot tones;

Figure 13 is another main composition structured flowchart based on the pilot frequency multiplexing device of IFDMA of the present invention.

Embodiment

Purpose of design of the present invention is to provide the mode that a kind of a plurality of user can multiplexed pilot symbol frequency domain, makes that the interval between each pilot sub-carrier on the frequency pilot sign frequency domain diminishes, to obtain interpolation processing effect preferably.

Below in conjunction with each accompanying drawing main realization principle of the present invention and embodiment thereof are explained in detail.

Please refer to Fig. 5, this figure is the main realization principle flow chart that the present invention is based on the pilot multiplex method of IFDMA, is mainly used in to carry out pilot frequency multiplexing at least between the frequency pilot sign of (as a TTI or several TTI) two and user data symbol time-division in a channel estimation period to handle its main implementation procedure as follows:

Step S10 sets the subcarrier density that the user takies greater than the user in the subcarrier density that takies during the data symbol during each frequency pilot sign; Wherein can be set at time span less than data symbol by time span and realize that data subcarrier density is greater than pilot sub-carrier density frequency pilot sign; Can also realize that as pilot sub-carrier data subcarrier density is greater than pilot sub-carrier density by selected part subcarrier in data subcarrier.

Step S20 carries out packet transaction with the user; Data subcarrier position relation between each user among the every group of user who wherein divides into groups can be adjacent; Data subcarrier position relation between each user also can be at random.

Step S30, every group of each interior user staggered pilot sub-carrier that takies each other between each frequency pilot sign.Its specific implementation comprises:

Each user in every group alternately takies each pilot sub-carrier according to original sequencing on first frequency pilot sign frequency domain; And

On next frequency pilot sign frequency domain, after the sequencing of each user in this group changed mutually, on frequency domain, alternately take each pilot sub-carrier.

Wherein on each frequency pilot sign frequency domain, alternately take the pilot sub-carrier that spectrum overlapping is arranged with the data subcarrier of self between every group of each interior user.

Wherein the pilot sub-carrier ratio of every group of each interior CU is identical.

According to the IFDMA technical characterstic of narrating in the above-mentioned prior art, the phase rotation coefficient of supposing k user data symbol is Φ (k), and then the phase rotation coefficient of the frequency pilot sign of one of them half symbol lengths of this user just is 2 Φ (i), wherein Wherein L represents the number of repetition of data block, Expression rounds downwards.

Fig. 6 has provided according to the inventive method principle, is the data symbol that provides of example and the first example multiplex mode schematic diagram of frequency pilot sign with 4 users, promptly works as L=4; K=0,1,2,3 o'clock, concern that according to above-mentioned formula correspondence obtains i=0,2,1,3, that is to say when 4 users interweave frequency division multiplexing, these 4 users are respectively 0,1 at the phase pushing figure that data division is, 2,3, phase pushing figure at pilot portion then is respectively 0,2,1,3, and be to carry out phase place rotation with the step-length of twice, be equivalent to that per two adjacent users of broach are divided into one group in the data division, these two users alternately take and oneself data subcarrier has the pilot sub-carrier of spectrum overlapping.That is to say that the multiplexing order of user is 0,1,2,3 in the data, and the multiplexing order of user is 0,2 in the pilot tone, 1,3.

This shows that the IFDMA system that utilizes the inventive method to realize is more suitable to the user of high-speed motion usually.And in order better to follow the tracks of the user's of high-speed motion time varying channel, usually in a channel estimation period, can adopt a plurality of times to go up the frequency pilot sign that disperses, based on this principle, the present invention also proposes the phase rotation coefficient of the frequency pilot sign of above-mentioned k user's second half symbol lengths is made as 2 Φ (j) here, wherein

Promptly work as L=4; K=0,1,2,, obtain j=2,0 at 3 o'clock according to above-mentioned formula correspondence, 3,1, that is to say that in second frequency pilot sign, these 4 users' phase deviation is respectively 2,0,3,1, and be to carry out the phase place rotation with the step-length of twice, be equivalent to that per two adjacent users of broach are divided into one group in the data division, in first frequency pilot sign, alternately take and own data subcarrier has the pilot sub-carrier of spectrum overlapping, in second frequency pilot sign, behind on the same group these two user's exchange sequences, alternately take the pilot sub-carrier that spectrum overlapping is arranged with the data subcarrier of oneself again.That is to say that the multiplexing order of user is 0,1,2,3 in the data, and the multiplexing order of user is 0,2 in first pilot tone, the multiplexing order of user is 1,3 in 1,3, the second pilot tone, 0,2.Specifically as shown in Figure 7, for being the data symbol that provides of example and the second example multiplex mode schematic diagram of frequency pilot sign with 4 users according to the inventive method principle;

As shown in Figure 7, under such pilot frequency multiplexing mode, the subcarrier at two the frequency pilot sign places of same user in a channel estimation period corresponds to data subcarrier and presents a kind of staggered state, in fact be equivalent to dwindle the subcarrier spacing of frequency pilot sign on frequency domain, therefore can have obtained frequency domain interpolation treatment effect preferably.

Certainly, when the IFDMA system had disposed more than two pilot tones for the user, also can adopting on the same group between these a plurality of pilot tones, the user alternately took the pilot sub-carrier mode that spectrum overlapping is arranged with the data subcarrier of oneself.

Certainly, also might not the user that the frequency domain broach is adjacent be divided into one group, any 2 users can divide the formation group, on the same group between the user between a plurality of pilot tones the staggered pilot sub-carrier that takies each other.Pilot sub-carrier also might not have spectrum overlapping with this user's data subcarrier.Being illustrated in figure 8 as according to the inventive method principle is the data symbol that provides of example and the 3rd example multiplex mode schematic diagram of frequency pilot sign with 4 users; As shown in the drawing, user 0 and 2 is divided into one group here, and user 1 and 3 is divided into one group.

In addition, also can select to divide grouping more than 2 users, and user's rule according to the rules staggered pilot sub-carrier that takies each other between a plurality of pilot tones on the same group.Being illustrated in figure 9 as according to the inventive method principle is the data symbol that provides of example and the first example multiplex mode schematic diagram of frequency pilot sign with 6 users, 3 pilot tones.

Correspondingly, with respect to the method for above-mentioned proposition, the present invention has also proposed a kind of pilot frequency multiplexing device based on IFDMA here, please refer to Figure 10, and this figure is the main composition structured flowchart that the present invention is based on the pilot frequency multiplexing device of IFDMA; It mainly comprises:

Setup unit 10 is set the subcarrier density that the user takies greater than the user in the subcarrier density that takies during the data symbol during each frequency pilot sign;

Grouped element 20 is used for the user is carried out packet transaction;

Multiplexing Unit 30, each user in every group of being used for grouped element 20 is told is the staggered pilot sub-carrier that takies each other between each frequency pilot sign that setup unit 10 is set.

Wherein Multiplexing Unit 30 specifically comprises:

Pilot sub-carrier alternately takies subelement, is used for every group of each interior user and alternately takies each pilot sub-carrier according to original sequencing on first frequency pilot sign frequency domain;

The user changes subelement in proper order, is used at next frequency pilot sign frequency domain, and the sequencing of each user in the group is changed processing; Described pilot sub-carrier alternately takies each pilot sub-carrier after alternately taking subelement each user's in group sequencing transposing on this next frequency pilot sign frequency domain.

Accordingly, the invention allows for a kind of pilot multiplex method based on IFDMA, be another main realization principle flow chart of the present invention as shown in figure 11 based on the pilot multiplex method of IFDMA, be mainly used in a channel estimation period and carry out pilot frequency multiplexing between the frequency pilot sign of at least two and user data symbol time-division and handle, its main implementation procedure is as follows:

Step S100 sets the pilot sub-carrier density that the user takies greater than the user in the data subcarrier density that takies on the data symbol frequency domain on each frequency pilot sign frequency domain;

Step S110, a selected frequency pilot sign in the frequency pilot sign after above-mentioned setting is handled; On selected frequency pilot sign frequency domain, determine the shared pilot sub-carrier of each user;

Step S120 on other each frequency pilot sign frequency domains, carries out the cyclic shift processing of identical shift amount respectively with definite shared pilot sub-carrier of each user on the described selected frequency pilot sign frequency domain; For different frequency pilot sign frequency domains, shift amount selected when the shared pilot sub-carrier of each user is carried out shifting processing is different.

Promptly preferably, all can also be carried out simultaneously the user of parallel transmission data symbol as a grouping, take all pilot sub-carriers by identical frequency hopping mode is staggered between a plurality of pilot tones between the user in this grouping, as shown in figure 12 for being the data symbol that provides of example and the second example multiplex mode schematic diagram of frequency pilot sign with 6 users, 3 pilot tones according to the inventive method principle:

Wherein the shared pilot sub-carrier position of each user is a cyclic shift of each pilot sub-carrier position in the pilot tone 1 in the pilot tone 2, the pilot sub-carrier shift amount of different user is identical, the position of the pilot sub-carrier of each CU is another cyclic shift of each pilot sub-carrier position in the pilot tone 1 in the pilot tone 3, through after this mode multiplexing, all be to have less subcarrier spacing on the frequency domain of each user's pilot sub-carrier in 3 pilot tones.

Respective needle is to the other method of above-mentioned proposition, the corresponding pilot frequency multiplexing device that has proposed a kind of based on IFDMA of the present invention, and as shown in figure 13, it mainly comprises:

Setup unit 100 is used to set the pilot sub-carrier density that the user takies greater than the user in the data subcarrier density that takies on the data symbol frequency domain on each frequency pilot sign frequency domain;

Selected unit 110 is used for selecting a frequency pilot sign at each frequency pilot sign that setup unit 100 is set after handling;

Pilot sub-carrier determining unit 120 is determined the shared pilot sub-carrier of each user on the frequency pilot sign frequency domain that is used for selecting in selected unit 110;

Shifting processing unit 130, be used at other each pilot sub-carriers, pilot sub-carrier determining unit 120 is being selected the cyclic shift processing that the shared pilot sub-carrier of determining on the frequency pilot sign frequency domain of selecting unit 110 of each user carries out identical shift amount respectively; For different pilot sub-carriers, the shift amount when the shared pilot sub-carrier of each user is carried out shifting processing is different.

Obviously, those skilled in the art can carry out various changes and modification to the present invention and not break away from the spirit and scope of the present invention.Like this, if of the present invention these are revised and modification belongs within the scope of claim of the present invention and equivalent technologies thereof, then the present invention also is intended to comprise these changes and modification interior.

Claims (11)

1, a kind of pilot multiplex method based on interlaced FDMA is used in a channel estimation period carrying out pilot frequency multiplexing between the frequency pilot sign of at least two and user data symbol time-division and handles, and comprises step:

The subcarrier density that A, setting user take during each frequency pilot sign greater than the user in the subcarrier density that takies during the data symbol;

B, the user is carried out packet transaction;

C, every group of each interior user staggered pilot sub-carrier that takies each other between each frequency pilot sign.

2, the method for claim 1 is characterized in that, in the described steps A is to be set at time span less than data symbol by the time span with frequency pilot sign to realize that data subcarrier density is greater than pilot sub-carrier density.

3, the method for claim 1 is characterized in that, realizes that as pilot sub-carrier data subcarrier density is greater than pilot sub-carrier density by selected part subcarrier in data subcarrier in the described steps A.

4, the method for claim 1 is characterized in that, the data subcarrier position relation between each user among the described step B among every group of user is adjacent; Or

Data subcarrier position relation between each user is at random.

5, the method for claim 1 is characterized in that, the implementation procedure of described step C specifically comprises:

C1, every group of each interior user alternately take each pilot sub-carrier according to original sequencing on first frequency pilot sign frequency domain; And

C2, on next frequency pilot sign frequency domain, after the sequencing of each user in this group changed mutually, on frequency domain, alternately take each pilot sub-carrier.

6, as claim 1 or 5 described methods, it is characterized in that, on each frequency pilot sign frequency domain, alternately take the pilot sub-carrier that spectrum overlapping is arranged with the data subcarrier of self between described every group of each interior user.

As claim 1 or 5 described methods, it is characterized in that 7, the pilot sub-carrier ratio of each CU among the described step C in every group is identical.

8, a kind of pilot frequency multiplexing device based on interlaced FDMA is used in a channel estimation period carrying out pilot frequency multiplexing between the frequency pilot sign of at least two and user data symbol time-division and handles, and comprising:

Setup unit is set the subcarrier density that the user takies greater than the user in the subcarrier density that takies during the data symbol during each frequency pilot sign;

Grouped element is used for the user is carried out packet transaction;

Multiplexing Unit, each user in every group of being used for described grouped element is told is the staggered pilot sub-carrier that takies each other between each frequency pilot sign that described setup unit is set.

9, method as claimed in claim 8 is characterized in that, described Multiplexing Unit specifically comprises:

Pilot sub-carrier alternately takies subelement, is used for every group of each interior user and alternately takies each pilot sub-carrier according to original sequencing on first frequency pilot sign frequency domain;

The user changes subelement in proper order, is used at next frequency pilot sign frequency domain, and the sequencing of each user in the group is changed processing; Described pilot sub-carrier alternately takies each pilot sub-carrier after alternately taking subelement each user's in group sequencing transposing on this next frequency pilot sign frequency domain.

10, a kind of pilot multiplex method based on interlaced FDMA is used in a channel estimation period carrying out pilot frequency multiplexing between the frequency pilot sign of at least two and user data symbol time-division and handles, and comprises step:

A. set the pilot sub-carrier density that the user takies greater than the user in the data subcarrier density that takies on the data symbol frequency domain on each frequency pilot sign frequency domain;

B. a selected frequency pilot sign;

C. on described selected frequency pilot sign frequency domain, determine the shared pilot sub-carrier of each user;

D. on other each frequency pilot sign frequency domains, definite shared pilot sub-carrier of each user on the described selected frequency pilot sign frequency domain is carried out the cyclic shift processing of identical shift amount respectively; For different frequency pilot sign frequency domains, shift amount selected when the shared pilot sub-carrier of each user is carried out shifting processing is different.

11, a kind of pilot frequency multiplexing device based on interlaced FDMA is used in a channel estimation period carrying out pilot frequency multiplexing between the frequency pilot sign of at least two and user data symbol time-division and handles, and comprising:

Setup unit is used to set the pilot sub-carrier density that the user takies greater than the user in the data subcarrier density that takies on the data symbol frequency domain on each frequency pilot sign frequency domain;

Selected unit is used for a selected frequency pilot sign;

The pilot sub-carrier determining unit is determined the shared pilot sub-carrier of each user on the frequency pilot sign frequency domain that is used for selecting in described selected unit;

The shifting processing unit, be used at other each pilot sub-carriers, described pilot sub-carrier determining unit is being selected the cyclic shift processing that the shared pilot sub-carrier of determining on the selected frequency pilot sign frequency domain in unit of each user carries out identical shift amount respectively; For different pilot sub-carriers, the shift amount when the shared pilot sub-carrier of each user is carried out shifting processing is different.

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