CN101325442B - Multi-antenna system and data transmission method thereof - Google Patents

Abstract

The invention relates to a wireless communication system, which discloses a multi-antenna system and a data transmitting method. In the invention, the plural phase sequence in the MIMO precoding system of CDD is improved, to cause the phase shift in the whole system bandwidth equal to CDD, meanwhile the variable step of the plural phase sequence is set to be equal to the corresponding sub-carrier of the precoding feedback bandwidth, thereby keeping higher precoding performance when the feedback bandwidth is greater relative to the whole frequency band ratio. The virtual cycle time delay can be changed along the time, thereby obtaining the diversity effect on the time. When the channel frequency has small selectivity, the virtual cycle time delay makes the minimum to obtain the dispatching gain.

Description

Multiaerial system and data transmission method for uplink thereof

Technical field

The present invention relates to wireless communication field, particularly the lift-off technology of multiple-input and multiple-output (Multiple InputMultiple Output is called for short " MIMO ") system.

Background technology

Along with the development of wireless mobile communications, two major techniques have been proposed in recent years: multi-carrier OFDM (Orthogonal Frequency Division Multiplexing is called for short " OFDM ") technology and MIMO technology.Because multipath characteristics that can overcome wireless channel well that the OFDM technology is had and the characteristics higher than single carrier frequency spectrum efficiency, and, spectrum efficiency that can increase wireless communication system that the MIMO technology is had and the characteristics that improve reliability; Make mutually combining of these two kinds of technology become the key technology in the GSM.

Respectively these two kinds of technology are carried out brief account below.

The transmitting terminal theory diagram of a simple single-antenna transmission ofdm system is as shown in Figure 1, comprises chnnel coding, constellation mapping, subcarrier mapping, OFDM modulation, adds Cyclic Prefix (Cyclic Prefix is called for short " CP "), sends these several parts.The ofdm system receiving terminal theory diagram that this single antenna receives is as shown in Figure 2, comprises that time-domain signal receives, goes CP, OFDM demodulation, separates mapping, channel estimating, equilibrium, constellation mapping, these several parts of channel decoding.

The MIMO technology settles a plurality of antennas to transmit and receive respectively at the transmitting terminal and the receiving terminal of communication system exactly, and the MIMO technology mainly can be divided into two types.When there are a plurality of transmitting antennas in transmitting terminal or receiving terminal, and during the identical data of each antenna emission, the signal that receiving terminal can obtain a plurality of branches merges, and improves the reliability of transmission, and we are called the multi-antenna diversity technology with the MIMO technology of this type.In addition; When there are a plurality of antenna in transmitting terminal and receiving terminal simultaneously, because mimo channel can equivalence become a plurality of parallel channels, so the transmitting terminal transmission multichannel data that can walk abreast simultaneously; Thereby can improve transmission rate, we are called space multiplexing technique with the technology of this type.

Cyclic Delay Diversity (Cyclic Delay Diversity; Be called for short " CDD ") be a kind of multiple antennas transmit diversity scheme commonly used in the ofdm system; Send identical frequency domain data on each antenna and the OFDM symbol of time domain is carried out different circulation delays, obtain frequency diversity gain with this.Adopt the transmitting terminal theory diagram of CDD emission as shown in Figure 3.

As can be seen from Figure 3, all adopted different circulation delay D on each antenna _m, m=1,2 ... M.Suppose the symbol of X (k) expression frequency domain; The sampling point of x (n) expression time domain can be known according to the character of DFT (DiscreteFourier Transform is called for short " DFT "); Circulation delay on the time domain is equivalent to the phase shift on the frequency domain, thereby can obtain following formula: $\mathrm{DFT}\left[x{\left((n-D)\right)}_N\right]=X\left(k\right)e^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="H071C6181220070706E000011.png,H071C6181220070706E000012.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;\; KD}}{N}};$ Wherein N representes counting of DFT, and k representes the numbering of subcarrier, k=0, and 1,2 ..., N-1.

Can the frequency-region signal that receive be expressed as:

$Y\left(k\right)=\underset{m=1}{\overset{M}{\mathrm{\&Sigma;}}}{H}_m\left(k\right)X\left(k\right)e^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="H071C6181220070706E000011.png,H071C6181220070706E000012.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;}{\mathrm{kD}}_m}{N}}+N\left(k\right)=X\left(k\right)\underset{m=1}{\overset{M}{\mathrm{\&Sigma;}}}{H}_m\left(k\right)e^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="H071C6181220070706E000011.png,H071C6181220070706E000012.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2{\mathrm{\&pi;kD}}_m}{N}}+N\left(k\right),k=0,\&CenterDot;\&CenterDot;\&CenterDot;N-1$

Wherein Y (k) expression is the reception signal on the k number of sub-carrier, H _m(k) m transmitting antenna on the k number of sub-carrier of expression is to domain channel response between the reception antenna.What N (k) represented is additive white Gaussian noise.

From the result of following formula, finding out, can be the multiaerial system equivalence of adopting CDD a single aerial system a: Y (k)=H _e(k) X (k)+N (k), k=0 ... N-1,

Its equivalent channel is: $H_e\left(k\right)=\underset{m=1}{\overset{M}{\mathrm{\&Sigma;}}}{H}_m\left(k\right)e^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="H071C6181220070706E000011.png,H071C6181220070706E000012.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{{2\mathrm{\&pi;\; KD}}_m}{N}},k=0,\&CenterDot;\&CenterDot;\&CenterDot;N-1$

Can find out that from following formula equivalent channel is that a plurality of channels are multiplied by different phase shifts stack afterwards, the effect of stack is to make that the speed of channel fluctuation increases.Suppose that for single footpath channel, there is flat decline in channel on frequency domain, the amplitude of the equivalent channel of the single-antenna transmission of this channel and double antenna CDD emission is as shown in Figure 4.

Channel has increased in the fluctuation of frequency domain after as can be seen from Figure 4 introducing CDD, just can obtain frequency diversity gain through on frequency domain, data being carried out chnnel coding, thereby improves the reliability of transmission.

MIMO precoding (MIMO precoding) is a kind of space multiplexing technique commonly used in the ofdm system, improves transmission rate through on a plurality of transmitting antennas, sending multichannel data simultaneously.Precoding is the meaning of precoding, (or claiming weighting) the just emission afterwards of just will encoding to data.With two transmitting antennas, two reception antennas is example, and the emission principle figure of MIMO precoding is as shown in Figure 5.

As can be seen from Figure 5 the frequency domain data symbol through emission after the precoding can be expressed as:

$\left[\begin{array}{c}{y}_1\left(n\right)\\ y_2\left(n\right)\end{array}\right]=\left[\begin{array}{cc}{w}_{11}& w_{12}\\ w_{21}& w_{22}\end{array}\right]\left[\begin{array}{c}{x}_1\left(n\right)\\ x_2\left(n\right)\end{array}\right],$ Here we usually will $W=\left[\begin{array}{cc}{w}_{11}& w_{12}\\ w_{21}& w_{22}\end{array}\right]$ Be called the precoding matrix.Through after the channel, the frequency-region signal that receiving terminal receives can be expressed as:

$\left[\begin{array}{c}{r}_1\left(n\right)\\ r_2\left(n\right)\end{array}\right]=\left[\begin{array}{cc}{h}_{11}& h_{12}\\ h_{21}& h_{22}\end{array}\right]\left[\begin{array}{c}{y}_1\left(n\right)\\ y_2\left(n\right)\end{array}\right]$

$=\left[\begin{array}{cc}{h}_{11}& h_{12}\\ h_{21}& h_{22}\end{array}\right]\left[\begin{array}{cc}{w}_{11}& w_{12}\\ w_{21}& w_{22}\end{array}\right]\left[\begin{array}{c}{x}_1\left(n\right)\\ x_2\left(n\right)\end{array}\right],$

$=\mathrm{HWX}$ H wherein _Ij, i, j=1,2 expression reception antenna i are to the domain channel response between the transmitting antenna j.We can carry out singular value decomposition (Sigular ValueDecomposition is called for short " SVD "), H=UDV to channel matrix H ^H

U wherein, V is a unitary matrice, and D is a diagonal matrix, and the element of diagonal matrix is exactly the channel gain of mimo channel subchannel.If precoding matrix W=V can be set, so because V is a unitary matrice, so HW=UDV ^HV=UD.As long as this moment, receiving terminal was used matrix U ^HCarry out weighting to the received signal, just can obtain multichannel does not have interference signals.

Z＝U ^HHWX＝U ^HUDX＝DX

Therefore can find out that the benefit of signal being carried out the precoding weighting just is and can signal map to the subchannel of each quadrature, reduces each road interference between signals.

Introduced a kind of scheme that CDD and MIMO precoding are combined in the prior art, we are referred to as CDD precoding here, are example with two transmitting antennas, two reception antennas, and its transmitting terminal schematic diagram is as shown in Figure 6.As can be seen from Figure 6, first antenna is not done circulation delay, and promptly circulation delay is zero.Suppose that second circulation delay on the antenna is d, can know that from the discussion of front the frequency-region signal that CDD precoding is sent can be expressed as so: $\left[\begin{array}{c}{\mathrm{<figure-callout\; id="1"\; label="y"\; filenames="H071C6181220070706E000021.png,H071C6181220070706E000041.png"\; state="\{\{state\}\}">y</figure-callout>}}_1^{\&prime;}\left(n\right)\\ {\mathrm{<figure-callout\; id="2"\; label="y"\; filenames="H071C6181220070706E000011.png,H071C6181220070706E000012.png"\; state="\{\{state\}\}">y</figure-callout>}}_2^{\&prime;}\left(n\right)\end{array}\right]=\left[\begin{array}{cc}1& 0\\ 0& e^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="H071C6181220070706E000011.png,H071C6181220070706E000012.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{2\mathrm{\&pi;\; Kd}}{N}}\end{array}\right]\left[\begin{array}{cc}{w}_{11}& w_{12}\\ w_{21}& w_{22}\end{array}\right]\left[\begin{array}{c}{x}_1\left(n\right)\\ x_2\left(n\right)\end{array}\right],$ Wherein the definition of k and N is all described identical with preceding text.

In ofdm system, be divided into the experimental process carrier wave owing to whole frequency band; And can distribute to different users to different subcarriers; Therefore the frequency domain dispatching technology is widely used in ofdm system; Promptly when communicate by letter with a plurality of users simultaneously in the base station, each user is always dispatched top-quality that section resource of respective channels give it.Because each user's channel is different, the best resource of channel quality can not repeat on very big possibility, therefore so can take what one needs.Through dispatching the throughput that can effectively improve whole system, we are called multi-user diversity gain or scheduling gain with this gain.Yet when the multipath number of channel was fewer, corresponding frequency domain channel fluctuation maybe be very little; The channel quality of user on whole frequency band is all similar, is unfavorable for multi-subscriber dispatching like this, through introducing the CDD technology; Can increase the fluctuation of channel, make it possible to carry out better frequency domain dispatching.

Yet, be not that channel fluctuation is favourable more to frequency domain dispatching more greatly.Usually when carrying out frequency domain dispatching, whole frequency band being divided into some groups of subcarriers, is that unit is dispatched with the group, one group of subcarrier is called Resource Block here.Therefore several best Resource Block of scheduling its channel quality of time-division provisioned user hope that channel quality is approaching in a Resource Block, and the fluctuation of channel is less.This just need be controlled at the time delay value in the smaller scope when introducing the CDD technology, to guarantee promptly can increase the fluctuation of channel, can not make that again violent variation takes place channel in a Resource Block.

Prior art hour is prolonged CDD and just can be increased scheduling and gain through introducing, and can not cause very big influence to performance for estimating channel.CDD and MIMO precoding are combined, hope exactly under the fewer channel of channel multi-path number, can increase multi-user diversity gain and obtain the MIMO gain.

We hope that weighting matrix W can equal the matrix V that channel decomposing goes out as far as possible when carrying out MIMO precoding in the prior art; But adopting FDD (Frequency Division Duplex; Abbreviation " FDD ") in the wireless communication system; Usually transmitting terminal can't obtain the information of channel matrix H, therefore needs receiving terminal to give transmitting terminal with feedback of channel information.In theory, the channel response on each number of sub-carrier is different, need feed back the channel response on each subcarrier respectively, but will bring a large amount of expenses like this, can reduce the efficient of communication system greatly.Because the subcarrier upper signal channel response adjacent exists correlation, therefore in order to reduce feedback, only to one group of adjacent channel information of subcarrier feedback, we are called feedback bandwidth with the bandwidth of the correspondence of this group subcarrier here usually.We are desirably within the feedback bandwidth so, and the variation of channel is smaller as far as possible, on this bandwidth, use identical precoding matrix can obtain more performance like this, i.e. weighting can be better and channel matched.

Inventor of the present invention finds; CDD is equivalent to introduce phase shift to frequency domain channel; Can increase the fluctuation of channel at frequency domain; If the fluctuation of channel is too big in feedback bandwidth, will make and can't well mate with the channel in the whole feedback bandwidth with a precoding matrix, cause performance decrease.In the prior art; Use the CDD correspondence when the phase shift on the frequency domain k number of sub-carrier is

as d=1; Suppose to have 2048 number of sub-carrier on the whole frequency band, feedback bandwidth is 60 number of sub-carrier.We can calculate so; Every at a distance from a number of sub-carrier, the transmitting antenna of having introduced CDD is-2 pi/2 048 ≈-0.17 ° to the phase shift that the channel between the receiving terminal antenna takes place, and is same; In feedback bandwidth is that phase shift is-0.17 * 60=-10.2 ° on 60 number of sub-carrier.Can find out that CDD influence to channel in feedback bandwidth is less when bandwidth ratio is big.But when d=1, suppose whole frequency band only in 128 number of sub-carrier, so every is-2 π/128 ≈-2.81 ° at a distance from the corresponding phase shift of a number of sub-carrier, is that phase shift on 60 number of sub-carrier is-2.81 * 60=-168.6 ° in feedback bandwidth.It is thus clear that when system bandwidth was smaller, CDD influence to channel in feedback bandwidth was bigger, can reduce the performance of precoding.

Summary of the invention

The technical problem underlying that embodiment of the present invention will solve provides a kind of multiaerial system and data transmission method for uplink thereof, still can keep higher precoding performance when making feedback bandwidth with respect to the whole frequency band large percentage.

For solving the problems of the technologies described above, execution mode of the present invention provides a kind of data transmission method for uplink of multiaerial system, comprises in this system that M is used for antenna transmission, and M >=2 wherein may further comprise the steps:

Frequency domain data to be sent and pre-coding matrix multiplied each other generates the data of M road through precoding, and the M road is through the data of a precoding corresponding M antenna respectively;

For each antenna, will to should antenna a road through the data map of the precoding part or all of subcarrier in the N number of sub-carrier;

For each antenna, be that ((k's jCf D)+jE) multiplies each other, wherein for the plural phase sequence exp of N with the data on the N number of sub-carrier and length; C and E are real number, and (k D) is a discontinuous function to f, and k and D are f (k; D) variable of function, k are the numbering of subcarrier, 0≤k≤N-1; D is the period of change or the step-length of this function, and f after the value of D is confirmed (k, D) saltus step takes place along with the variation of k is every at a distance from D in the value of function;

For each antenna, the data on the N number of sub-carrier are carried out modulating in OFDM after, through this antenna emission.

Execution mode of the present invention also provides a kind of multiaerial system, comprising:

M is used for antenna transmission, wherein M >=2;

Precoding unit, being used for frequency domain data to be sent and pre-coding matrix multiplied each other generates the data of M road through precoding, and every road is through the data of precoding one in the corresponding M antenna respectively;

M map unit corresponds respectively to M antenna, each map unit be respectively applied for precoding unit output a road through the data map of the precoding part or all of subcarrier in the N number of sub-carrier;

M multiplication unit corresponds respectively to M antenna, and each multiplication unit is respectively applied for a map unit is mapped to the plural phase sequence exp (jCf (k that data and length on the N number of sub-carrier are N; D)+jE) multiply each other, wherein, C and E are real number; (k D) is a discontinuous function to f, and k and D are f (k; D) variable of function, k are the numbering of subcarrier, 0≤k≤N-1; D is the period of change or the step-length of this function, and f after the value of D is confirmed (k, D) saltus step takes place along with the variation of k is every at a distance from D in the value of function;

M OFDM modulating unit corresponds respectively to M antenna, and each OFDM modulating unit is respectively applied for the data of a multiplication unit output are carried out OFDM modulation back through the corresponding antenna transmission.

Embodiment of the present invention compared with prior art, the main distinction and effect thereof are:

Through at frequency domain with data on the transmitting antenna N number of sub-carrier and plural phase sequence exp (jCf (k; D)+jE) multiply each other; Phase shift and the CDD of channel on the whole system bandwidth equated; Obtain frequency diversity or multi-subscriber dispatching gain that CDD brings; Be arranged to equate through the step-length that plural phase sequence is changed,, can solve the problem of precoding decreased performance under the smaller situation of system bandwidth effectively for the MIMO precoding system that uses CDD with the corresponding subcarrier number of the feedback bandwidth of precoding.

Description of drawings

Fig. 1 is a single-antenna transmission ofdm system transmitting terminal theory diagram in the prior art;

Fig. 2 is that single antenna receives the OFDM system receiving terminal theory diagram in the prior art;

Fig. 3 is a CDD emission principle block diagram in the prior art;

Fig. 4 is the amplitude sketch map of the equivalent channel of single-antenna transmission and double antenna CDD emission in the prior art;

Fig. 5 is a MIMO precoding transmitting terminal theory diagram in the prior art;

Fig. 6 is a CDD precoding emission principle block diagram in the prior art;

Fig. 7 is the data transmission method for uplink flow chart according to multiaerial system in the first embodiment of the invention;

Fig. 8 is to be 2.5MHz according to system bandwidth in the first embodiment of the invention, and number of terminals was respectively 1,5,10 o'clock, and the performance of PSD precoding and CDD precoding is sketch map relatively;

Fig. 9 is to be 5MHz according to system bandwidth in the first embodiment of the invention, and the UE number was respectively 1,5,10 o'clock, and the performance of PSD precoding and CDD precoding is sketch map relatively;

Figure 10 is according to multiaerial system structure chart in the four embodiment of the invention.

Embodiment

For making the object of the invention, technical scheme and advantage clearer, embodiment of the present invention is done to describe in detail further below in conjunction with accompanying drawing.

First embodiment of the invention relates to a kind of data transmission method for uplink of multiaerial system, comprises in this system that M is used for antenna transmission, wherein M >=2.Idiographic flow is as shown in Figure 7.

In step 710, with p road frequency domain data symbol to be sent $\left[\begin{array}{c}{x}_1\left(n\right)\\ x_2\left(n\right)\\ \&CenterDot;\\ \&CenterDot;\\ \&CenterDot;\\ x_p\left(n\right)\end{array}\right]$ With pre-coding matrix

Multiplying each other generates the data of M road through precoding, and in the corresponding M antenna is distinguished through the data of precoding in every road.

In step 720, for each antenna, will to should antenna a road through the data map of precoding in the N number of sub-carrier partly or entirely.If system only sends a user's data a moment, then can this user's data be mapped in whole N number of sub-carrier; If system will send a plurality of user's data simultaneously; Then each user's data can be mapped in the parton carrier wave, for example, and for two users' situation; Can in preceding N/2 number of sub-carrier, shine upon first user's data, second user's data of mapping in the N/2 number of sub-carrier of back.

In step 730, for each antenna, ((k's jCf D)+jE) multiplies each other the plural phase sequence exp that the data and the length that are mapped on the above-mentioned N number of sub-carrier are N; Wherein, C and E are real number, and (k D) is a discontinuous function to f; K and D be f (k, the D) variable of function, k are the numbering of subcarrier, 0≤k≤N-1; D is the period of change or the step-length of this function, and (k, D) value of function at a distance from D a saltus step takes place f after the value of D is confirmed along with the variation of k is every.

In concrete the application, ((k D)+jE) can be jCf this plural number phase sequence exp

Or

Wherein, m is the sequence number of this antenna, d _mBe the virtual cycle delay on this antenna, B is the corresponding subcarrier number of feedback bandwidth of this pre-coding matrix precoding, promptly uses the number of the adjacent sub-carrier of identical precoding matrix, and k is the numbering of subcarrier, and 0≤k≤N-1, k are integer,

Expression rounds downwards and rounds up respectively,

Be initial phase.Wherein, M the pairing M of antenna virtual cycle delay d _mIn, have two kinds of different values at least.

With

is that example specifies; Wherein, suppose that initial phase is 0.Frequency-region signal after multiplying each other can be expressed as:

Can know that from background technology the CDD technical equivalences is in being d with time delay _mAntenna on the frequency domain data value of being multiplied by of sending do K=0,1 ..., the phase shift of N, here can with $\{e^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="H071C6181220070706E000011.png,H071C6181220070706E000012.png"\; state="\{\{state\}\}">j</figure-callout>}\frac{{2\mathrm{\&pi;\; Kd}}_m}{N}},k=\mathrm{0,1},\&CenterDot;\&CenterDot;\&CenterDot;,N\}$ Regard a plural phase sequence as, CDD is equivalent to the data of frequency domain and this plural phase sequence is multiplied each other.

Be with the difference of CDD technology; In this execution mode; The data and the plural phase sequence that are mapped on the N number of sub-carrier are multiplied each other; Can find out, when this plural number phase sequence is the integral multiple of the corresponding subcarrier number of feedback bandwidth B at subcarrier subscript k, identical with corresponding plural phase sequence among the CDD; When k is not the integral multiple of B; Close with the corresponding plural phase sequence among the CDD, thus guarantee that phase shift and the CDD of channel on the whole system bandwidth equates in this execution mode, obtain frequency diversity or multi-subscriber dispatching gain that CDD brings.When k is not the integral multiple of B, because k is rounded after divided by B, make that the plural phase sequence of being taken advantage of is identical, wherein when under subcarrier, being designated as iB～(i+1) between the B-1 downwards $i=\mathrm{0,1},\&CenterDot;\&CenterDot;\&CenterDot;,\frac{N}{B},$ Every separated B number of sub-carrier plural number phase sequence just can take place once to change.That is to say; The step-length that plural phase sequence changes is arranged to equate with the corresponding subcarrier number of the feedback bandwidth of precoding; Its plural phase sequence that multiplies each other is identical for each subcarrier in the same feedback bandwidth; Thereby for the MIMO precoding system that uses CDD, the channel fluctuation of each subcarrier in the different feedback bandwidth is more obvious, and the channel fluctuation of each subcarrier in the same feedback bandwidth is less; Thereby can satisfy the demand of frequency domain dispatching better, can solve the problem of precoding decreased performance under the smaller situation of system bandwidth effectively.

When the plural number phase sequence is got

; It is similar that its effect and plural phase sequence are got

; Its difference only is that the former is for rounding up; The latter repeats no more at this for rounding downwards.

Need to prove, in this execution mode with the cycle time-delay d of antenna in the plural phase sequence _mBe called virtual cycle delay; This is because the frequency-region signal representation formula from step 730 can find out that in fact each antenna does not carry out cycle time-delay in this execution mode; Just when B=1, frequency domain is multiplied by corresponding plural phase sequence and is equivalent in time domain and has carried out a cycle time-delay.When B was not equal to 1, being multiplied by corresponding plural phase sequence can not equivalence carry out cycle time-delay for time domain, so be referred to as virtual cycle delay in this execution mode.

In step 740,, the data on this N number of sub-carrier are carried out the OFDM modulation for each antenna.

In step 750, after adding CP, send through respective antenna through the data of OFDM modulation.

Describe with the effect of concrete example to this execution mode below, still getting initial phase with plural phase sequence is 0 to be example.Suppose to have two transmitting antennas, d on first antenna ₁D on=0, second antenna ₂=1.On whole frequency band, there are 2048 number of sub-carrier; Feedback bandwidth is under the situation of 60 number of sub-carrier; Can calculate; In the 1st feedback bandwidth (i.e. the 0th～59 number of sub-carrier); The phase shift of introducing on second transmitting antenna for

because k＜60; Therefore

equals 0, so phase shift also is 0 °.In the 2nd feedback bandwidth (i.e. the 60th～119 number of sub-carrier); It is corresponding that phase shift be in the 3rd feedback bandwidth (i.e. the 120th～179 number of sub-carrier), correspondence phase shift is

by that analogy.It is thus clear that this execution mode can equally with CDD guarantee on the whole system bandwidth, can introduce 360 ° (d=1) or 720 ° of (d=2) phase shifts, thereby the fluctuation of increase frequency domain channel obtains the frequency diversity gain that CDD brings.Simultaneously, can guarantee again not change,, can solve the problem of precoding decreased performance under the smaller situation of system bandwidth effectively to guarantee the performance of precoding in a feedback bandwidth upper signal channel phase place.

It is thus clear that; Through the data on the transmitting antenna N number of sub-carrier and plural phase sequence

or

being multiplied each other at frequency domain; Phase shift and the CDD of channel on the whole system bandwidth equated; Obtain frequency diversity or multi-subscriber dispatching gain that CDD brings; Through the step-length setting of plural phase sequence variation and the corresponding subcarrier number of feedback bandwidth of precoding are equated; When this execution mode and MIMO precoding combination, can solve the decreased performance problem of under the smaller situation of system bandwidth, bringing when CDD and MIMOprecoding combine effectively.

Description for ease; The scheme that combines with MIMO precoding in this execution mode is called phase deviation divides collection (Phase Shift Diversity; Be called for short " PSD ") precoding, the scheme when CDD and MIMO precoding are combined is called CDD precoding.Fig. 8 and Fig. 9 provided respectively when system bandwidth be 2.5 and 5MHz, when number of terminals is respectively 1,5,10, the comparison of the analogue system of PSD precoding and CDD precoding.

Ordinate is represented user throughput among two figure, and abscissa is represented throughput of system.50% (being intermediate value) user's average throughput and the throughput of system performance that the solid line representative is the poorest, 5% (being cell edge) user's average throughput and the throughput of system performance that the dotted line representative is the poorest.CDD+Q=5RB representes PSDprecoding, and it is 0 that no CDD represents the time delay value of CDD.Three points on same curve are represented respectively in the sub-district by ordinate to have 1 from big to small, the situation when 5 and 10 users.

From Fig. 8 and Fig. 9, can find out; No matter be that system bandwidth is during for 2.5MHz or system bandwidth is when being 5MHz; Be perhaps to get intermediate value at cell edge; The user is how perhaps after a little while the PSD precoding of this execution mode is superior to CDD precoding on user throughput and two indexs of throughput of system in the sub-district.

Second embodiment of the invention relates to a kind of data transmission method for uplink of multiaerial system equally, and is roughly the same with first execution mode, and its difference is, in the first embodiment, and M M the virtual cycle delay d that antenna is corresponding _mDo not change in time, and in this execution mode, this M virtual cycle delay d _mCan time to time change, thus temporal diversity further obtained, further improved transmission performance.

Third embodiment of the invention relates to a kind of data transmission method for uplink of multiaerial system equally, and is roughly the same with first execution mode, and its difference is; In this execution mode, under the condition of total bandwidth less than 3 times of channel coherence bandwidths of system, the pairing virtual cycle delay dm of each antenna is 1 or 2; For example under the scene of spaciousness, do not have multipath basically, main power concentration is on Dan Jing; Though multipath is arranged perhaps but time delay between multipath is very little, in this case, with d _mBe set to 1 or 2, make when selectivity of channel frequency hour, virtual circulation delay can be got smaller value, to obtain the scheduling gain.

Four embodiment of the invention relates to a kind of multiaerial system, and is shown in figure 10, comprising: M is used for antenna transmission, wherein M>=2; Precoding unit, being used for frequency domain data to be sent and pre-coding matrix multiplied each other generates the data of M road through precoding, every road through the data of precoding respectively to should M in the antenna one; M map unit corresponds respectively to M antenna, each map unit be respectively applied for the output of this precoding unit a road through the data map of the precoding part or all of subcarrier in the N number of sub-carrier; M multiplication unit corresponds respectively to M antenna, and each multiplication unit is respectively applied for a map unit is mapped to the plural phase sequence exp (jCf (k that data and length on the N number of sub-carrier are N; D)+jE) corresponding step-by-step is multiplied each other, and wherein, C and E are real number; (k D) is a discontinuous function to f, and k and D are f (k; D) variable of function, k are the numbering of subcarrier, 0≤k≤N-1; D is the period of change or the step-length of this function, and f after the value of D is confirmed (k, D) saltus step takes place along with the variation of k is every at a distance from D in the value of function; M OFDM modulating unit corresponds respectively to M antenna, and each OFDM modulating unit is respectively applied for the data of a multiplication unit output are carried out the OFDM modulation; M CP unit corresponds respectively to M antenna, and each CP unit is respectively applied for the data of an OFDM modulating unit output are added Cyclic Prefix, with passing through the corresponding antenna emission through the data of adding Cyclic Prefix.

This plural number phase sequence exp (jCf (k D)+jE) can be:

Or

Wherein, m is the sequence number of antenna, d _mBe the virtual cycle delay on the antenna, in the pairing M of this M antenna virtual cycle delay, have two kinds of different values at least, B is the corresponding subcarrier number of feedback bandwidth of pre-coding matrix, and k is the numbering of subcarrier, 0≤k≤N-1,

Expression rounds downwards and rounds up respectively,

Be initial phase.

Through the data on the transmitting antenna N number of sub-carrier and plural phase sequence

or

being multiplied each other at frequency domain; Phase shift and the CDD of channel on the whole system bandwidth equated; Obtain frequency diversity or multi-subscriber dispatching gain that CDD brings; Be arranged to equate through the step-length that plural phase sequence is changed with the corresponding subcarrier number of the feedback bandwidth of precoding; For the MIMO precoding system that uses CDD, can solve the problem of precoding decreased performance under the smaller situation of system bandwidth effectively.

Wherein, each multiplication unit can use the d that does not change in time _m, perhaps, each multiplication unit can change d in time _mValue, thereby further obtain temporal diversity, further improved transmission performance.

Under the condition of total bandwidth less than 3 times of channel coherence bandwidths of this system, the pairing virtual cycle delay of each antenna is 1 or 2, thus when selectivity of channel frequency hour, virtual circulation delay can be got smaller value, to obtain the scheduling gain.

In sum; In embodiments of the present invention; Through the data on the transmitting antenna N number of sub-carrier and plural phase sequence

or

being multiplied each other at frequency domain; Phase shift and the CDD of channel on the whole system bandwidth equated; Obtain frequency diversity or multi-subscriber dispatching gain that CDD brings; Be arranged to equate through the step-length that plural phase sequence is changed with the corresponding subcarrier number of the feedback bandwidth of precoding; For the MIMOprecoding system that uses CDD, can solve the problem of precoding decreased performance under the smaller situation of system bandwidth effectively.

Virtual cycle delay can time to time change, thereby further obtains temporal diversity, has further improved transmission performance.

When selectivity of channel frequency hour, virtual circulation delay can be got smaller value, to obtain the scheduling gain.

Though through reference some preferred implementation of the present invention; The present invention is illustrated and describes; But those of ordinary skill in the art should be understood that and can do various changes to it in form with on the details, and without departing from the spirit and scope of the present invention.

Claims (8)

1. the data transmission method for uplink of a multiaerial system comprises in this system that M is used for antenna transmission, and wherein M >=2 is characterized in that, may further comprise the steps:

Frequency domain data to be sent and pre-coding matrix multiplied each other generates the data of M road through precoding, and said M road is distinguished corresponding through the data of precoding with said M antenna;

For each antenna, will be to a road said data map through precoding that should the antenna part or all of subcarrier in the N number of sub-carrier;

For each antenna, be that ((k's jCf D)+jE) multiplies each other, wherein for the plural phase sequence exp of N with the data on the said N number of sub-carrier and length; C and E are real number, and (k D) is a discontinuous function to f, and k and D are f (k; D) variable of function, k are the numbering of subcarrier, and 0≤k≤N-1, N are the subcarrier number on the whole system bandwidth; D is the period of change or the step-length of this function, and f after the value of D is confirmed (k, D) saltus step takes place along with the variation of k is every at a distance from D in the value of function;

For each antenna, the data on the said N number of sub-carrier are carried out sending after the modulating in OFDM;

Said plural phase sequence exp (jCf (k D)+jE) is:

Wherein, m is the sequence number of said antenna, d _mBe the virtual cycle delay on the said antenna, B is the corresponding subcarrier number of feedback bandwidth of said pre-coding matrix, and k is the numbering and the 0≤k≤N-1 of subcarrier,

Expression rounds downwards and rounds up respectively,

Be initial phase.

2. the data transmission method for uplink of multiaerial system according to claim 1 is characterized in that, said virtual cycle delay changes in time, and perhaps, said virtual cycle delay does not change in time.

3. the data transmission method for uplink of multiaerial system according to claim 1 is characterized in that, the pairing M of a said M antenna virtual cycle delay has two kinds of different values at least.

4. according to the data transmission method for uplink of each described multiaerial system in the claim 1 to 3, it is characterized in that, between the step of said OFDM modulation and the step of said emission, further comprising the steps of:

To adding Cyclic Prefix through the data of OFDM modulation.

5. a multiaerial system is characterized in that, comprising:

M is used for antenna transmission, wherein M >=2;

Precoding unit, being used for frequency domain data to be sent and pre-coding matrix multiplied each other generates the data of M road through precoding, and every road is through the data of precoding one in the corresponding said M antenna respectively;

M map unit corresponds respectively to a said M antenna, and each map unit is respectively applied for said every road of said precoding unit output through the data map of the precoding part or all of subcarrier in the N number of sub-carrier;

M multiplication unit corresponds respectively to a said M antenna, and each multiplication unit is respectively applied for and a said map unit is mapped to the plural phase sequence exp that data and length on the said N number of sub-carrier is N ((k's jCf D)+jE) multiplies each other; Wherein, C and E are real number, f (k; D) be a discontinuous function, k and D are f (k, D) variable of function; K is the numbering of subcarrier, and 0≤k≤N-1, N are the subcarrier number on the whole system bandwidth; D is the period of change or the step-length of this function, and f after the value of D is confirmed (k, D) saltus step takes place along with the variation of k is every at a distance from D in the value of function;

M OFDM modulating unit corresponds respectively to a said M antenna, and each OFDM modulating unit is respectively applied for the data of a said multiplication unit output are carried out OFDM modulation back through the corresponding antenna transmission;

Said plural phase sequence exp (jCf (k D)+jE) is:

Wherein, m is the sequence number of said antenna, d _mBe the virtual cycle delay on the said antenna, B is the corresponding subcarrier number of feedback bandwidth of said pre-coding matrix, and k is the numbering of subcarrier, 0≤k≤N-1,

Expression rounds downwards and rounds up respectively,

Be initial phase.

6. multiaerial system according to claim 5 is characterized in that, said multiplication unit uses the virtual cycle delay that changes in time, and perhaps, said multiplication unit uses and do not change virtual cycle delay in time.

7. multiaerial system according to claim 7 is characterized in that, the pairing M of a said M antenna virtual cycle delay has two kinds of different values at least.

8. according to each described multiaerial system in the claim 5 to 7, it is characterized in that, also comprise:

M cyclic prefix CP unit corresponds respectively to M said antenna, and each cyclic prefix unit is respectively applied for adds Cyclic Prefix to the data of a said OFDM modulating unit output, and the data of warp being added Cyclic Prefix are through the corresponding antenna emission.

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