CN101282198A - Transmission method and terminal for upstream multi-antenna in TDD system - Google Patents

Abstract

The present invention discloses a transmission method of uplink multiple-antenna in time division duplex (TDD) system, wherein the terminal in the TDD system comprises at least two transmission antennae. The method comprises the following steps: executing channel estimation by the terminal according to the common reference symbol transmitted from the base station to obtain the state information of the downlink channel; confirming the time delay value of each transmission antenna itself in the uplink circulating time delay diversity transmission according to the state information of the downlink channel; and executing uplink transmission on each transmission antenna itself according to the time delay value. The invention furthermore discloses a transmission terminal of the uplink multiple-antenna in the TDD system. With the invention when the terminal in the TDD system executes uplink circulating time delay diversity transmission, the adopted time delay value can be confirmed according to the characteristic of the channel to improve the performance.

Description

Upstream multi-antenna transmission method and terminal in a kind of TDD system

Technical field

The present invention relates to wireless communication technology field, relate in particular to upstream multi-antenna transmission method and terminal in a kind of TDD system.

Background technology

OFDM (OFDM) is a kind of wideband transmit technology that is suitable for using in multi-path environment, but ofdm system itself does not have the diversity ability, therefore is necessary to adopt corresponding diversity technique to obtain higher reliability.In the ofdm system of DVB-T and HIPERLAN/2, adopt frequency-domain-interleaving, in frequency-selective channel, can improve the performance of convolution decoder.But for flat fading channel, just obtained performance gain in this way.Space Time Coding technology based on diversity maximization strategy can obtain diversity and coding gain by the redundant information and the encoding relation of space, introducing on the time, but conventional space time coding scheme all needs the recipient to carry out corresponding decoding when empty, causes the raising of receiver complexity.

(Delay Diversity DD) is a kind of space diversity reception to communicate of ofdm system to postpone diversity.Transmit leg in the DD system uses a plurality of antennas to transmit, the signal that sends on different bays has different delays, time delay expansion by artificial manufacturing makes equivalent channel produce frequency selectivity, forward error control (FEC) mechanism can be utilized this frequency selectivity and produce frequency diversity gain, improves the error probability performance of system.The receiver structure of DD system and single antenna receiver are in full accord, do not need extra processing module.But (Inter SymbolInterference, ISI), its time delay size must be subject to protection interval (Guard Period, GP) size of time slot in the radio frames in the intersymbol interference that causes for fear of DD.

For fear of the problems referred to above, (Cyclic Delay Diversity, CDD) in the system, the signal of each antenna branch is through parallel transmission the in circulation skew back at cyclic delay diversity.Because do not have real delay between the signal of each antenna branch, thereby can not produce the problem of ISI, cycle offset also can not be subjected to the restriction of GP.For receiving terminal, the circulation skew only is equivalent to the variation of equivalent channel, does not therefore increase the complexity of receiver.CDD also can be considered to a kind of Space Time Coding, and for some other Space Time Coding technology, there is not the antenna number quantitative limitation in CDD, does not have the loss of speed yet.

Suppose that the number of samples in the OFDM symbol is N _F, the number of transmit antennas of CDD system is N, the circulation delay amount with respect to first antenna on n antenna branch is $0\≤{\mathrm{\δ}}_n^{\mathrm{CY}}\≤\frac{N_F}{2},$ N=0 wherein ..., N-1.Generally speaking, the retardation between any two adjacent antennas is identical, is called the retardation increment, is assumed to be τ, and, $0\≤\mathrm{\τ}\≤\frac{N_F}{2(N-1)},$ N＞1, so

${\mathrm{\δ}}_0^{\mathrm{CF}}=0$

${\mathrm{\δ}}_1^{\mathrm{CF}}=\mathrm{\τ}$

...

${\mathrm{\δ}}_n^{\mathrm{CF}}=n\·\mathrm{\τ}$

...

${\mathrm{\δ}}_N^{\mathrm{CF}}=(N-1)\·\mathrm{\τ}$

Adopt the ofdm system transmitter principle of CDD can be as shown in Figure 1:

Input signal through FEC, interweave, modulate also anti-fast Fourier transform (IFFT) after, be assigned to N antenna branch and get on, the signal on each antenna branch has different circulation delay amounts.Be without loss of generality, the circulation delay amount of first antenna branch is set to 0.Because the circulation delay of a plurality of branch roads is equivalent to produce multipath transmisstion through the stack after the Channel Transmission for the recipient.And adopt extra processing procedures (except that channel estimating) such as receiver does not need to merge behind the CDD, do not increase the complexity of receiver.The recipient removes Cyclic Prefix (CP) afterwards, directly carries out fast Fourier transform (FFT), the merging of M road high specific (MRC) and demodulation, deinterleaving and decoding, and its receiver structure as shown in Figure 2.

CDD signal on the antenna n can (Inverse Discrete FourierTransform IDFT) be expressed as by Inverse Discrete Fourier Transform

Wherein l represents discrete time, and k represents discrete frequency.Definition phase deviation sequence

$C_n\left(k\right)=e^{-j\frac{2\mathrm{\π}}{N_F}k{\mathrm{\δ}}_n^{\mathrm{CY}}},$

By top description as can be seen, the CDD signal on the antenna n is equivalent to frequency-region signal S (k) is used C _n(k) carry out carrying out after the phase place deflection OFDM modulation, (Phase Diversity, PD) equivalent implementation as shown in Figure 3 can to obtain the phase diversity of CDD signal thus again.

The circulation delay of CDD appears at before the Cyclic Prefix, and the time delay side-play amount of equivalence is not subjected to the restriction of CP and only is subjected to the restriction that OFDM modulates, thereby can improve the frequency selectivity of equivalent channel under the prerequisite that does not increase the expansion of actual signal time delay.If note h _{M, n}(k) be that n transmitting branch is to the channel transfer function of m receiving branch on k the subcarrier, then the equivalent channel transfer function of m reception antenna correspondence can be expressed as:

$h_m^{\left(\mathrm{eq}\right)}\left(k\right)=\underset{n=0}{\overset{N-1}{\mathrm{\Σ}}}{C}_n\left(k\right)\·h_{m,n}\left(k\right)$

The raising of the frequency selectivity of equivalent channel transfer function as can be seen from the above equation.

As can be seen from the above equation, receiver will synthesize the equivalent channel transfer function, needs to estimate the channel transfer function h of each transmitting antenna to reception antenna _{M, n}And obtain the phase deviation sequence C (k), _n(k).For receiver is estimated the channel transfer function h of each transmitting antenna to reception antenna _{M, n}(k), the transmitting antenna of transmitter need be launched mutually orthogonal frequency pilot sign, and receiver utilizes this frequency pilot sign to carry out h _{M, n}(k) estimation claims that this pilot tone that is used for channel estimating and demodulation, detection is demodulation (Demodulation, DM) pilot tone.Therefore transmit diversity or other preliminary treatment such as time-delay owing to generally public guide frequency is not circulated require receiver must know the retardation of each transmitting antenna of transmitter in advance, obtain the phase deviation sequence C according to this retardation receiver _n(k), could synthesize the equivalent channel transfer function then.The circulation delay amount of each transmitting antenna branch road is generally all chosen fixing quantity in each sub-district, and need be by signaling with this parameter notice receiver.

In existing system, the provisional capital need be measured channel quality by specific frequency pilot sign up and down simultaneously, and this pilot tone is called channel quality indication (Channel Quality Indicator, CQI) pilot tone.Similar with the DM pilot tone, to the CQI pilot tone delay diversity that circulates, transmitter need not launched mutually orthogonal CQI pilot tone to transmitter on different transmitting antennas.Up CQI measures by the base station and handles, and terminal needs to feed back to the base station after measuring CQI in the down link, and the base station basis is carried out scheduling of resource and modulating-coding pattern (Modulation﹠amp to the tracking of the CQI of link; Coding Scheme, selection MCS).

As seen, there is following shortcoming in prior art:

(1) terminal can not be selected delay volume according to the characteristic of channel;

In existing time division multiplexing (TDD) system, when terminal circulated the delay diversity processing to upstream data, the delay volume of use was predefined fixing delay volume, can not be complementary with the characteristic of channel, makes system errors probability performance lower;

(2) terminal need be prenoticed receiver by signaling with the delay volume that uses;

The base station is surveyed and is carried out the estimation of CDD equivalent channel, when promptly carrying out equivalent channel transfer function synthetic, be by the estimation of the channel response of each transmitting antenna branch road and the delay volume of knowing are in advance synthesized, terminal must be passed through the employed CDD delay volume in signaled base station so.If terminal is adjusted the CDD delay volume, must send its adjusted CDD delay volume of corresponding signaled receiver once more, strengthened the signaling consumption between terminal and the base station.

(3) terminal need send mutually orthogonal CQI pilot tone on different transmit antennas;

Terminal need send the CQI pilot tone of quadrature on different transmit antennas, the measurement of channel quality is carried out according to this CQI pilot tone in the base station, and the design complexities of CQI pilot tone and relevant pilot measurement work are all comparatively complicated.

Summary of the invention

The invention provides the transmission method and the terminal of upstream multi-antenna in a kind of TDD system, in order to solve in the prior art terminal in the TDD system when carrying out the transmission of uplink cycle delay diversity, can not determine delay volume according to the characteristic of channel, and then cause the lower problem of system errors probability performance.

The transmission method of upstream multi-antenna in a kind of TDD system provided by the invention may further comprise the steps:

A. the common reference symbol sent according to the base station of terminal is carried out channel estimating, obtains the state information of down channel;

B. described terminal is determined self each transmitting antenna employed time delay value when the uplink cycle delay diversity transmits according to the state information of described down channel;

C. described terminal is according to described time delay value, carries out uplink on self each transmitting antenna.

The state information of described down channel comprises the down channel transmission matrix, and then step B comprises:

B0. described terminal is utilized described down channel transmission matrix, obtains the up channel transmission matrix, and this up channel transmission matrix is the transposed matrix of described down channel transmission matrix;

B1. described terminal is utilized described up channel transmission matrix, determines self each transmitting antenna employed time delay value when the uplink cycle delay diversity transmits.

Preserve more than one time delay value increment in described terminal, and the employed ascending resource piece of described terminal uses identical time delay value when the uplink cycle delay diversity transmits, then step B1 comprises:

At described each time delay value increment, determine the effective signal-to-noise ratio of this time delay value increment correspondence, the method of determining is: for the subcarrier in described each ascending resource piece, utilize maximization effective signal-to-noise ratio mapping method, according to described time delay value increment and described up channel transmission matrix, obtain the effective signal-to-noise ratio of this time delay value increment correspondence;

The time delay value increment of maximum effective signal-to-noise ratio correspondence in the effective signal-to-noise ratio of selecting to obtain, employed time delay value when determining that according to this time delay value increment each transmitting antenna of described terminal circulates the delay diversity transmission.

Preserve more than one time delay value increment in described terminal, and the employed ascending resource piece of described terminal uses different time delay values when the uplink cycle delay diversity transmits, then step B1 comprises:

For described each ascending resource piece, employed time delay value when each transmitting antenna of determining described terminal utilizes this ascending resource piece to circulate the delay diversity transmission, the method for determining is:

At described each time delay value increment, for the subcarrier in the described ascending resource piece, utilize maximization effective signal-to-noise ratio mapping method, according to time delay value increment and described up channel transmission matrix, obtain the effective signal-to-noise ratio of this time delay value increment correspondence; The time delay value increment of maximum effective signal-to-noise ratio correspondence in the effective signal-to-noise ratio of selecting to obtain, employed time delay value when determining that according to this time delay value increment each transmitting antenna of described terminal utilizes described ascending resource piece to circulate the delay diversity transmission.

Step C comprises:

Described terminal is used described time delay value, and the demodulation DM pilot tone of upstream data and these data of demodulation is circulated sends to the base station after delay diversity is handled.

This method further comprises:

Described terminal is used described time delay value, and the CQI pilot tone that will be used for uplink signal-channel quality indication CQI estimation circulates and sends to the base station after delay diversity is handled.

This method further comprises:

Described terminal sends mutually orthogonal CQI pilot tone to the base station on each transmitting antenna of self, and described time delay value is fed back to the base station.

The present invention also provides the terminal of carrying out the upstream multi-antenna transmission in a kind of TDD system, and this terminal is used for:

According to the common reference symbol that send the base station, carry out channel estimating, obtain the state information of down channel; According to the state information of described down channel, determine self each transmitting antenna employed time delay value when the uplink cycle delay diversity transmits; According to described time delay value, on self each transmitting antenna, carry out uplink.

This terminal comprises:

Receiving element is used to receive the common reference symbol that send the base station, carries out channel estimating according to this common reference symbol, obtains the state information of down channel;

Determining unit is used for the state information according to described down channel, determines each transmitting antenna of terminal employed time delay value when the uplink cycle delay diversity transmits;

Transmission unit is used for according to described time delay value, carries out uplink on each transmitting antenna of terminal.

Described determining unit comprises:

Upstream cell is used for utilizing the down channel transmission matrix of described downlink channel condition information, obtains the up channel transmission matrix, and this up channel transmission matrix is the transposed matrix of described down channel transmission matrix;

The delay value unit is used to utilize described up channel transmission matrix, determines each transmitting antenna of terminal employed time delay value when the uplink cycle delay diversity transmits.

Described delay value unit comprises:

Memory cell is used to preserve more than one time delay value increment;

First computing unit, be used for when the employed ascending resource piece of described terminal uses identical time delay value when the uplink cycle delay diversity transmits, at described each time delay value increment, determine the effective signal-to-noise ratio of this time delay value increment correspondence, the method of determining is: for the subcarrier in described each ascending resource piece, utilize maximization effective signal-to-noise ratio mapping method,, obtain the effective signal-to-noise ratio of this time delay value increment correspondence according to described time delay value increment and described up channel transmission matrix; The time delay value increment of maximum effective signal-to-noise ratio correspondence in the effective signal-to-noise ratio of selecting to obtain, employed time delay value when determining that according to this time delay value increment each transmitting antenna of described terminal circulates the delay diversity transmission.

Second computing unit, be used for when the employed ascending resource piece of described terminal uses different time delay values when the uplink cycle delay diversity transmits, for described each ascending resource piece, employed time delay value when each transmitting antenna of determining described terminal utilizes this ascending resource piece to circulate the delay diversity transmission, the method of determining is: at described each time delay value increment, for the subcarrier in the described ascending resource piece, utilize maximization effective signal-to-noise ratio mapping method, according to time delay value increment and described up channel transmission matrix, obtain the effective signal-to-noise ratio of this time delay value increment correspondence; The time delay value increment of maximum effective signal-to-noise ratio correspondence in the effective signal-to-noise ratio of selecting to obtain, employed time delay value when determining that according to this time delay value increment each transmitting antenna of described terminal utilizes described ascending resource piece to circulate the delay diversity transmission.

Described transmission unit is used for:

Use described time delay value, the demodulation DM pilot tone of upstream data and these data of demodulation is circulated sends to the base station after delay diversity is handled.

Described transmission unit also is used for:

Use described time delay value, the CQI pilot tone that will be used for uplink signal-channel quality indication CQI estimation circulates and sends to the base station after delay diversity is handled.

Described transmission unit also is used for:

On each transmitting antenna of terminal, send mutually orthogonal CQI pilot tone, and described time delay value is fed back to the base station to the base station.

Adopt the present invention, in the TDD system, terminal is utilized the reciprocity of TDD system up-downgoing channel, utilize the channel information of measured channel information acquisition up channel in the down channel, determine the time delay value of up CDD transmission again according to the channel information of up channel, realized time delay value, improved the error probability performance of system according to the adaptive selection of characteristic of channel CDD transmission.

Simultaneously, the time delay value that the terminal utilization is determined carries out DM pilot tone or CQI pilot tone to carry out uplink again after CDD handles,, the terminal different transmit antennas can be used identical DM pilot tone or identical CQI pilot tone, thereby has saved the pilot design complexity.

In addition, the time delay value that the terminal utilization is determined carries out DM pilot tone and CQI pilot tone to carry out uplink again after CDD handles, for the reception of base station in the up link, be not to know that each terminal transmitting antenna is to the channel response between the receiving antenna array of base station, and can directly the CDD channel of equivalence be estimated, and then carry out Data Detection and CQI measurement.So can save the signaling consumption that sends each antenna time delay value to base station receiver.

Description of drawings

Fig. 1 is the transmitter operation principle schematic diagram of the ofdm system of available technology adopting CDD;

Fig. 2 is the operation of receiver principle schematic of the ofdm system of available technology adopting CDD;

Fig. 3 is the phase diversity equivalence implementation schematic diagram of CDD in the prior art;

Fig. 4 is a method flow schematic diagram provided by the invention;

Fig. 5 is the schematic flow sheet of method embodiment provided by the invention;

Fig. 6 is a terminal structure schematic diagram provided by the invention.

Embodiment

The invention provides the upstream multi-antenna transmission method in a kind of TDD system, in the TDD system, when terminal has many transmit antennas, can adopt circulation delay diversity technology to carry out uplink,, specifically comprise referring to Fig. 4:

Step 401: terminal obtains the state information of down channel according to the descending common reference symbol from the base station that receives;

Step 402: terminal is determined the time delay value when up CDD transmits according to the state information of the down channel that obtains;

Step 403: terminal sends according to the time delay value of determining carries out uplink;

This step specifically comprises:

The CDD processing is carried out in the DM pilot tone unification of upstream data and these data of demodulation, and the data of transmitting on the promptly same transmitting antenna adopt identical time delay value to transmit with the DM pilot tone, and different transmit antennas can be used identical DM pilot tone;

The CQI pilot tone that is used for up CQI estimation is carried out the CDD processing, only needs one group of CQI pilot tone that is used to estimate CQI this moment; Perhaps, the CQI pilot tone that is used for up CQI estimation is not carried out the CDD processing, and need transmit the CQI pilot tones of different groups this moment on different transmit antennas, and each organizes between the CQI pilot tone orthogonal.

Below in conjunction with specific embodiment, the present invention will be described:

In the present embodiment, suppose that the antenna for base station number is M, the terminal antenna number is N.When descending transmission, the base station uses M antenna to send, and terminal uses N antenna to receive, and writing down capable Channel Transmission matrix is H ^DL∈ C ^{N * M}Referring to Fig. 5, terminal carries out adaptively selected delay volume and up CDD transmission specifically comprises:

Step 501: the base station sends mutually orthogonal common reference symbol to terminal on a plurality of antennas;

Step 502: the common reference symbol from the base station that the terminal utilization receives obtains downlink channel condition information;

Here, terminal is utilized the common reference symbol of m transmission antennas transmit of base station, estimates H ^DLM row, utilize M antenna for base station pilot transmitted symbol, terminal just can obtain complete down channel transmission matrix H ^DL

Step 503: terminal is utilized the reciprocity of TDD system up-downgoing channel, obtains the state information of up channel according to the state information of down channel;

Here, terminal is utilized the reciprocity of TDD system up-downgoing channel, can be directly by down channel transmission matrix H ^DLObtain up channel transmission matrix H ^UL=(H ^DL) ^T

Step 504: terminal is determined the time delay value when up CDD transmits according to the state information of up channel;

Here, terminal is directly utilized the up channel transmission matrix, determines the time delay value when up CDD transmits, i.e. δ _n ^CYDetermine δ _n ^CYThe time, can utilize the criterion of maximization effective signal-to-noise ratio to carry out determining of CDD propagation delay time value:

Equivalent channel on the m root antenna on k subcarrier of receiving terminal is:

$h_m^{\left(\mathrm{eq}\right)}\left(k\right)=\underset{n=0}{\overset{N-1}{\mathrm{\Σ}}}{C}_n\left(k\right)\·h_{m,n}^{\mathrm{UL}}\left(k\right)$

Wherein $C_n\left(k\right)=e^{-j\frac{2\mathrm{\π}}{N_F}k{\mathrm{\δ}}_n^{\mathrm{CY}}},$ h _{M, n} ^UL(k) be up channel transmission matrix H ^UL(k) the n root transmitting antenna in is to the transfer function of m root reception antenna.

So, the output signal-to-noise ratio on each subcarrier k of receiver end is:

${\mathrm{\γ}}_k=\frac{\underset{m}{\overset{M}{\mathrm{\Σ}}}{\left|h_m^{\left(\mathrm{eq}\right)}\left(k\right)\right|}^2}{{\mathrm{\σ}}^2}$

Wherein, σ ²For receiving noise, suppose that the noise of every reception antenna is identical.

Suppose that effective signal-to-noise ratio adopts maximization effective signal-to-noise ratio mapping (EESM) method to calculate, effective signal-to-noise ratio is so:

${\mathrm{SNR}}_{\mathrm{eff}}=-\mathrm{\β}\·\ln \left[\frac{1}{K}\underset{k=0}{\overset{K}{\mathrm{\Σ}}}\exp (-\frac{{\mathrm{\γ}}_k}{\mathrm{\β}})\right]$

Wherein β be use in the EESM mapping method with the modulation and the relevant parameter of encoding, this parameter can be definite in advance by emulation.K transmits the employed subcarrier sequence number of data for the user, and K is the total number of these subcarriers.

Supposing the system is given one group of optional time delay value increment τ in advance _l, l=0...L-1, wherein L is that system specifies

Supposing the system is given one group of optional time delay value increment τ in advance _l, l=0...L-1, wherein L is the size of the time delay value group of system's appointment.As shown in the table, be one group of optional time delay value under the L=8 situation:

So, different delay value increment τ _lCorresponding effective signal-to-noise ratio can be written as:

${\mathrm{SNR}}_{\mathrm{eff}}\left(l\right)=-\mathrm{\β}\·\ln \left[\frac{1}{K}\underset{k=0}{\overset{K}{\mathrm{\Σ}}}\exp (-\frac{{\mathrm{\γ}}_k}{\mathrm{\β}})\right]$

$=-\mathrm{\β}\·\ln \left[\frac{1}{K}\underset{k=0}{\overset{K}{\mathrm{\Σ}}}\exp (-\frac{1}{\mathrm{\β}}\frac{\underset{m}{\overset{M}{\mathrm{\Σ}}}{|\underset{n=0}{\overset{N-1}{\mathrm{\Σ}}}\exp (-j\frac{2\mathrm{\π}}{N_F}\mathrm{kn}{\mathrm{\τ}}_l)\·h_{m,n}^{\mathrm{UL}}\left(k\right)|}^2}{{\mathrm{\σ}}^2})\right]$

...................................................[1]

Terminal by selecting the time delay increment size τ ' of maximum effective signal-to-noise ratio correspondence, promptly can be determined the propagation delay time of each antenna according to formula [1] ${\mathrm{\δ}}_n^{\mathrm{CY}}=n{\mathrm{\τ}}^{\′}.$

Concrete, in the employed ascending resource piece of terminal, different Resource Block can use identical CDD delay volume, also can use different delay volumes in different Resource Block.

If all Resource Block use identical time delay value, K comprises subcarrier in all Resource Block when calculating effective signal-to-noise ratio so, at this moment, only need to calculate one group of effective signal-to-noise ratio, promptly increase the propagation delay time value that time delay increment size τ ' determines each antenna for each time delay value.

If the time delay value difference that each Resource Block uses, need calculate one group of effective signal-to-noise ratio at each Resource Block, in this group effective signal-to-noise ratio, select the time delay value increment τ ' of maximum effective signal-to-noise ratio correspondence then, determine the delay volume that corresponding Resource Block uses when carrying out uplink according to this time delay value increment τ '.At the concrete grammar that calculates effective signal-to-noise ratio at certain Resource Block be: for each time delay value increment τ _l, calculating its corresponding effective signal-to-noise ratio according to formula [1], the subcarrier k that uses this Resource Block to comprise when specifically calculating calculates, and promptly k implication at this moment is a subcarrier sequence number in the Resource Block, and K is a number of sub carrier wave in the Resource Block.

Step 505: terminal sends upstream data, DM pilot tone and CQI pilot tone according to the CDD propagation delay time value of determining;

After terminal is determined the CDD propagation delay time value of each transmitting antenna, upstream data is carried out the CDD transmission according to this time delay value.

Because up DM pilot tone is not used by other user, thereby can carry out sending after the CDD processing to DM pilot tone and upstream data unification, be that the data of transmitting on the same transmitting antenna adopt identical time delay value to transmit with the DM pilot tone, specifically choosing also of the delay volume on each antenna branch needn't be passed through the signaling base station.The base station directly utilizes the DM pilot tone through the CDD processing that receives to estimate equivalent channel, and the line data of going forward side by side receives.

In addition, among the present invention, the CQI pilot tone can also be carried out CDD and handle the back, can adopt following method to determine the delay value that it is concrete to the base station transmission:

If employed all Resource Block of uplink user data transmission use identical time delay value, the Resource Block that covered of the CQI reference symbol of each user feedback also uses identical time delay value so, K comprises the subcarrier in all Resource Block that this user feedback CQI reference symbol covered when calculating this delay value, and the time delay of data transmission value is decided by the length of delay of CQI reference symbol.If the time delay value difference that employed each Resource Block uses during the uplink user data transmission, the Resource Block that covered of the CQI reference symbol of each user feedback also uses different delay values so, when calculating this delay value, as long as each Resource Block uses own corresponding subcarrier to calculate respectively.

Use said method, can guarantee that the applied circulation delay value of CQI pilot tone is identical with the time delay value that the DM pilot tone of upstream data and these data of demodulation adopts, thereby the CQI value that makes the base station calculate is effective.

When the CQI pilot tone that is used for the CQI estimation did not circulate the delay diversity processing, terminal need be informed the circulation delay value to the base station by feedback channel that the estimation of CQI can be carried out according to the circulation delay value of feedback and the up channel matrix that estimates in the base station.Concrete, if the employed delay value difference of each Resource Block of terminal, the delay value of each Resource Block correspondence that terminal need occupy the CQI pilot tone is informed to the base station; If all Physical Resource Block of terminal uses identical delay value, terminal only need be fed back a delay value and gets final product so.Such as, can be with the time delay value increment τ that determines _lSequence number 1 feed back to the base station and get final product.

After the base station was surveyed and received the signal of handling through CDD, pilot signal that the process CDD that utilization receives handles and terminal were carried out the original pilots data before CDD handles, and carry out channel estimating, carry out data demodulates or channel quality estimation then, and concrete grammar is as follows:

The note original pilots is P, and the signal form that the pilot tone after handling through terminal CDD arrives m antenna of receiving terminal can be expressed as

Wherein r (k) represents the received signal on k the subcarrier, noise and interference on k subcarrier of n (k) expression.According to r (k) and known original pilots P (k), utilize conventional channel estimation methods can estimate equivalent channel h _m ^(eq)(k), utilize channel estimation results, can carry out data demodulates or channel quality estimation.

As seen, the present invention can produce following beneficial effect with respect to prior art:

Terminal can improve the error probability performance of system according to the delay volume of adaptive each antenna of selection of the characteristic of channel.This mode has been utilized the reciprocity of TDD system up-downgoing channel fully, utilizes in the down channel measured channel information to adjust up CDD transmission parameters, makes it to have more performance.

Simultaneously, the terminal different transmit antennas can be used identical DM pilot tone and CQI pilot tone, thereby saves the pilot design complexity.Because the selection of CDD delay parameter is determined by terminal, for the reception of base station in the up link, be not to know that each terminal transmitting antenna is to the channel response between the receiving antenna array of base station, and can directly the CDD channel of equivalence be estimated, thereby carry out Data Detection and CQI measurement.

In addition, can also save the signaling consumption that sends each antenna delay volume to base station receiver.Terminal independently determines the delay volume of CDD, and the base station is carrying out can not knowing the CDD delay volume when Data Detection and CQI estimate, therefore can omit the signaling consumption of coordinating the CDD delay volume between base station and the terminal.

Referring to Fig. 6, the present invention also provides the terminal of carrying out the upstream multi-antenna transmission in a kind of TDD system, and this terminal is used for: according to the common reference symbol that send the base station, carry out channel estimating, obtain the state information of down channel; According to the state information of described down channel, determine self each transmitting antenna employed time delay value when the uplink cycle delay diversity transmits; According to described time delay value, on self each transmitting antenna, carry out uplink.

This terminal comprises receiving element 601, determining unit 602 and transmission unit 603, and wherein, receiving element 601 is used to receive the common reference symbol that send the base station, carries out channel estimating according to this common reference symbol, obtains the state information of down channel; Determining unit 602 is used for the state information according to described down channel, determines each transmitting antenna of terminal employed time delay value when the uplink cycle delay diversity transmits; Transmission unit 603 is used for according to described time delay value, carries out uplink on each transmitting antenna of terminal.

Determining unit 602 comprises upstream cell 6021 and delay value unit 6022, wherein, upstream cell 6021, be used for utilizing the down channel transmission matrix of described downlink channel condition information, obtain the up channel transmission matrix, this up channel transmission matrix is the transposed matrix of described down channel transmission matrix; Delay value unit 6022 is used to utilize described up channel transmission matrix, determines each transmitting antenna of terminal employed time delay value when the uplink cycle delay diversity transmits.

Delay value unit 6022 comprises memory cell 60221, first computing unit 60222 and second computing unit 60223, and wherein, memory cell 60221 is used to preserve more than one time delay value increment; First computing unit 60222, be used for when the employed ascending resource piece of described terminal uses identical time delay value when the uplink cycle delay diversity transmits, at described each time delay value increment, determine the effective signal-to-noise ratio of this time delay value increment correspondence, the method of determining is: for the subcarrier in described each ascending resource piece, utilize maximization effective signal-to-noise ratio mapping method,, obtain the effective signal-to-noise ratio of this time delay value increment correspondence according to described time delay value increment and described up channel transmission matrix; The time delay value increment of maximum effective signal-to-noise ratio correspondence in the effective signal-to-noise ratio of selecting to obtain, employed time delay value when determining that according to this time delay value increment each transmitting antenna of described terminal circulates the delay diversity transmission.Second computing unit 60223, be used for when the employed ascending resource piece of described terminal uses different time delay values when the uplink cycle delay diversity transmits, for described each ascending resource piece, employed time delay value when each transmitting antenna of determining described terminal utilizes this ascending resource piece to circulate the delay diversity transmission, the method of determining is: at described each time delay value increment, for the subcarrier in the described ascending resource piece, utilize maximization effective signal-to-noise ratio mapping method, according to time delay value increment and described up channel transmission matrix, obtain the effective signal-to-noise ratio of this time delay value increment correspondence; The time delay value increment of maximum effective signal-to-noise ratio correspondence in the effective signal-to-noise ratio of selecting to obtain, employed time delay value when determining that according to this time delay value increment each transmitting antenna of described terminal utilizes described ascending resource piece to circulate the delay diversity transmission.

Transmission unit 603 is used for: use described time delay value, the DM pilot tone of upstream data and these data of demodulation is circulated sends to the base station after delay diversity is handled.

Transmission unit 603 also is used for: use described time delay value, the CQI pilot tone that will be used for uplink signal-channel quality indication CQI estimation circulates and sends to the base station after delay diversity is handled.Perhaps, on each transmitting antenna of terminal, send mutually orthogonal CQI pilot tone, and described time delay value is fed back to the base station to the base station.

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 (14)

1. the transmission method of upstream multi-antenna in the TDD system, the terminal in the described TDD system has at least two transmit antennas, it is characterized in that this method may further comprise the steps:

A. the common reference symbol sent according to the base station of terminal is carried out channel estimating, obtains the state information of down channel;

B. described terminal is determined self each transmitting antenna employed time delay value when the uplink cycle delay diversity transmits according to the state information of described down channel;

C. described terminal is according to described time delay value, carries out uplink on self each transmitting antenna.

2. the method for claim 1 is characterized in that, the state information of described down channel comprises the down channel transmission matrix, and then step B comprises:

B0. described terminal is utilized described down channel transmission matrix, obtains the up channel transmission matrix, and this up channel transmission matrix is the transposed matrix of described down channel transmission matrix;

B1. described terminal is utilized described up channel transmission matrix, determines self each transmitting antenna employed time delay value when the uplink cycle delay diversity transmits.

3. method as claimed in claim 2 is characterized in that, preserves more than one time delay value increment in described terminal, and the employed ascending resource piece of described terminal uses identical time delay value when the uplink cycle delay diversity transmits, and then step B1 comprises:

At described each time delay value increment, determine the effective signal-to-noise ratio of this time delay value increment correspondence, the method of determining is: for the subcarrier in described each ascending resource piece, utilize maximization effective signal-to-noise ratio mapping method, according to described time delay value increment and described up channel transmission matrix, obtain the effective signal-to-noise ratio of this time delay value increment correspondence;

The time delay value increment of maximum effective signal-to-noise ratio correspondence in the effective signal-to-noise ratio of selecting to obtain, employed time delay value when determining that according to this time delay value increment each transmitting antenna of described terminal circulates the delay diversity transmission.

4. method as claimed in claim 2 is characterized in that, preserves more than one time delay value increment in described terminal, and the employed ascending resource piece of described terminal uses different time delay values when the uplink cycle delay diversity transmits, and then step B1 comprises:

For described each ascending resource piece, employed time delay value when each transmitting antenna of determining described terminal utilizes this ascending resource piece to circulate the delay diversity transmission, the method for determining is:

At described each time delay value increment, for the subcarrier in the described ascending resource piece, utilize maximization effective signal-to-noise ratio mapping method, according to time delay value increment and described up channel transmission matrix, obtain the effective signal-to-noise ratio of this time delay value increment correspondence; The time delay value increment of maximum effective signal-to-noise ratio correspondence in the effective signal-to-noise ratio of selecting to obtain, employed time delay value when determining that according to this time delay value increment each transmitting antenna of described terminal utilizes described ascending resource piece to circulate the delay diversity transmission.

5. as claim 3 or 4 described methods, it is characterized in that step C comprises:

Described terminal is used described time delay value, and the demodulation DM pilot tone of upstream data and these data of demodulation is circulated sends to the base station after delay diversity is handled.

6. method as claimed in claim 5 is characterized in that, this method further comprises:

Described terminal is used described time delay value, and the CQI pilot tone that will be used for uplink signal-channel quality indication CQI estimation circulates and sends to the base station after delay diversity is handled.

7. method as claimed in claim 5 is characterized in that, this method further comprises:

Described terminal sends mutually orthogonal CQI pilot tone to the base station on each transmitting antenna of self, and described time delay value is fed back to the base station.

8. carry out the terminal that upstream multi-antenna transmits in a TDD system, it is characterized in that this terminal is used for:

According to the common reference symbol that send the base station, carry out channel estimating, obtain the state information of down channel; According to the state information of described down channel, determine self each transmitting antenna employed time delay value when the uplink cycle delay diversity transmits; According to described time delay value, on self each transmitting antenna, carry out uplink.

9. terminal as claimed in claim 8 is characterized in that, this terminal comprises:

Receiving element is used to receive the common reference symbol that send the base station, carries out channel estimating according to this common reference symbol, obtains the state information of down channel;

Determining unit is used for the state information according to described down channel, determines each transmitting antenna of terminal employed time delay value when the uplink cycle delay diversity transmits;

Transmission unit is used for according to described time delay value, carries out uplink on each transmitting antenna of terminal.

10. terminal as claimed in claim 9 is characterized in that, described determining unit comprises:

Upstream cell is used for utilizing the down channel transmission matrix of described downlink channel condition information, obtains the up channel transmission matrix, and this up channel transmission matrix is the transposed matrix of described down channel transmission matrix;

The delay value unit is used to utilize described up channel transmission matrix, determines each transmitting antenna of terminal employed time delay value when the uplink cycle delay diversity transmits.

11. terminal as claimed in claim 10 is characterized in that, described delay value unit comprises:

Memory cell is used to preserve more than one time delay value increment;

First computing unit, be used for when the employed ascending resource piece of described terminal uses identical time delay value when the uplink cycle delay diversity transmits, at described each time delay value increment, determine the effective signal-to-noise ratio of this time delay value increment correspondence, the method of determining is: for the subcarrier in described each ascending resource piece, utilize maximization effective signal-to-noise ratio mapping method,, obtain the effective signal-to-noise ratio of this time delay value increment correspondence according to described time delay value increment and described up channel transmission matrix; The time delay value increment of maximum effective signal-to-noise ratio correspondence in the effective signal-to-noise ratio of selecting to obtain, employed time delay value when determining that according to this time delay value increment each transmitting antenna of described terminal circulates the delay diversity transmission;

Second computing unit, be used for when the employed ascending resource piece of described terminal uses different time delay values when the uplink cycle delay diversity transmits, for described each ascending resource piece, employed time delay value when each transmitting antenna of determining described terminal utilizes this ascending resource piece to circulate the delay diversity transmission, the method of determining is: at described each time delay value increment, for the subcarrier in the described ascending resource piece, utilize maximization effective signal-to-noise ratio mapping method, according to time delay value increment and described up channel transmission matrix, obtain the effective signal-to-noise ratio of this time delay value increment correspondence; The time delay value increment of maximum effective signal-to-noise ratio correspondence in the effective signal-to-noise ratio of selecting to obtain, employed time delay value when determining that according to this time delay value increment each transmitting antenna of described terminal utilizes described ascending resource piece to circulate the delay diversity transmission.

12. terminal as claimed in claim 11 is characterized in that, described transmission unit is used for:

Use described time delay value, the demodulation DM pilot tone of upstream data and these data of demodulation is circulated sends to the base station after delay diversity is handled.

13. terminal as claimed in claim 12 is characterized in that, described transmission unit also is used for:

Use described time delay value, the CQI pilot tone that will be used for uplink signal-channel quality indication CQI estimation circulates and sends to the base station after delay diversity is handled.

14. terminal as claimed in claim 12 is characterized in that, described transmission unit also is used for:

On each transmitting antenna of terminal, send mutually orthogonal CQI pilot tone, and described time delay value is fed back to the base station to the base station.

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