CN101282198B - 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 by using the rule of maximize effective signal to noise ratio; 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 in multi-path environment, using, but ofdm system itself does not have branch energy collecting power, 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.Can obtain branch collection and coding gain through space, the redundant information of introducing on the time and encoding relation based on minute Space Time Coding technology of collection maximization strategy; 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 to divide collection.Transmit leg in the DD system uses a plurality of antennas to transmit; The signal that on different antennas array element, sends has different delays; Time delay expansion through 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 can not receive the restriction of GP yet.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 does

N=0 wherein ..., N-1.Generally speaking; Retardation between any two adjacent antennas is identical; Be called the retardation increment, be assumed to be τ, and;

N＞1, so

${\mathrm{\δ}}_0^{\mathrm{CY}}=0$

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

…

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

…

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

The ofdm system transmitter principle of employing 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 need not 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 is 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 representes discrete time, and k representes discrete frequency.Definition phase deviation sequence

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

Can find out that by top description 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 is as shown in Figure 3 can to obtain the Xiang Fenji 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 does not receive the restriction of CP and only receives the restriction that OFDM modulates, thereby can under the prerequisite that does not increase the expansion of actual signal time delay, improve the frequency selectivity of equivalent channel.If note h _{M, n}(k) be that n transmitting branch is to the channel transfer function of m receiving branch on the k number of sub-carrier, then m the corresponding equivalent channel transfer function of reception antenna can be expressed as:

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

Can find out the raising of the frequency selectivity of equivalent channel transfer function by following formula.

Can find out that by following formula receiver will synthesize the equivalent channel transfer function, need 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).Estimate the channel transfer function h of each transmitting antenna to reception antenna for receiver _{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 (Demodul ation, 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 needs through signaling this parameter notice receiver.

In existing system, the provisional capital need be measured channel quality through 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 the distinct transmit antenna.Up CQI measures by base station processes, and the terminal need be fed 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 & Coding Scheme, selection MCS) to the tracking of the CQI of link.

It is thus clear that there is following shortcoming in prior art:

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

In existing time division multiplexing (TDD) system, when the delay diversity processing was circulated to upstream data in the terminal, 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) receiver need be prenoticed through signaling with the delay volume that uses in the terminal;

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 through the estimation of the channel response of each transmitting antenna branch road and the delay volume of knowing are in advance synthesized, the employed CDD delay volume in signaled base station must be passed through in the terminal so.If terminal adjustment 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) mutually orthogonal CQI pilot tone need be sent in the terminal on different transmit antennas;

The CQI pilot tone of quadrature need be sent in the terminal 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 present 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 confirm 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; The state information of said down channel comprises the down channel transmission matrix;

B. said terminal utilizes said down channel transmission matrix, obtains the up channel transmission matrix, and this up channel transmission matrix is the transposed matrix of said down channel transmission matrix; Said terminal utilizes said up channel transmission matrix, confirms self each transmitting antenna employed time delay value when the uplink cycle delay diversity transmits;

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

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

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

B1. said terminal utilizes said up channel transmission matrix, confirms self each transmitting antenna employed time delay value when the uplink cycle delay diversity transmits.

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

To said each time delay value increment; Confirm the effective signal-to-noise ratio that this time delay value increment is corresponding; The method of confirming is: for the subcarrier in said each ascending resource piece; Utilize maximization effective signal-to-noise ratio mapping method,, obtain the corresponding effective signal-to-noise ratio of this time delay value increment according to said time delay value increment and said 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 confirming that according to this time delay value increment each transmitting antenna at said terminal circulates the delay diversity transmission.

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

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

To said each time delay value increment, for the subcarrier in the said ascending resource piece, utilize maximization effective signal-to-noise ratio mapping method, according to time delay value increment and said up channel transmission matrix, obtain the corresponding effective signal-to-noise ratio of this time delay value increment; 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 confirming that according to this time delay value increment each transmitting antenna at said terminal utilizes said ascending resource piece to circulate the delay diversity transmission.

Step C comprises:

Said time delay value is used at said terminal, 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:

Said time delay value is used at said terminal, 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:

Mutually orthogonal CQI pilot tone is sent to the base station in said terminal on each transmitting antenna of self, and said 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 comprises receiving element, confirms unit and transmission unit;

Said 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;

Said definite unit comprises upstream cell and delay value unit; Said upstream cell is used for utilizing the down channel transmission matrix of said downlink channel condition information, obtains the up channel transmission matrix, and this up channel transmission matrix is the transposed matrix of said down channel transmission matrix; Said delay value unit is used to utilize said up channel transmission matrix, confirms each transmitting antenna of terminal employed time delay value when the uplink cycle delay diversity transmits;

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

Said definite unit comprises:

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

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

Said delay value unit comprises:

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

First computing unit; When being used at said terminal that employed ascending resource piece uses identical time delay value when the uplink cycle delay diversity transmits,, confirm the effective signal-to-noise ratio that this time delay value increment is corresponding to said each time delay value increment; The method of confirming is: for the subcarrier in said each ascending resource piece; Utilize maximization effective signal-to-noise ratio mapping method,, obtain the corresponding effective signal-to-noise ratio of this time delay value increment according to said time delay value increment and said 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 confirming that according to this time delay value increment each transmitting antenna at said terminal circulates the delay diversity transmission.

Second computing unit; When being used at said terminal that employed ascending resource piece uses different time delay values when the uplink cycle delay diversity transmits; For said each ascending resource piece, employed time delay value when each transmitting antenna of confirming said terminal utilizes this ascending resource piece to circulate the delay diversity transmission, the method for confirming is: to said each time delay value increment; For the subcarrier in the said ascending resource piece; Utilize maximization effective signal-to-noise ratio mapping method,, obtain the corresponding effective signal-to-noise ratio of this time delay value increment according to time delay value increment and said 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 confirming that according to this time delay value increment each transmitting antenna at said terminal utilizes said ascending resource piece to circulate the delay diversity transmission.

Said transmission unit is used for:

Use said 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.

Said transmission unit also is used for:

Use said 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.

Said transmission unit also is used for:

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

Adopt the present invention; In the TDD system; The terminal utilizes the reciprocity of TDD system up-downgoing channel, utilizes the channel information of measured channel information acquisition up channel in the down channel, confirms 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 terminal utilizes the time delay value of confirming that DM pilot tone or CQI pilot tone are carried out carrying 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 terminal utilizes the time delay value of confirming that DM pilot tone and CQI pilot tone are carried out carrying out uplink again after CDD handles; For the reception of base station in the up link; Be not to know each terminal transmitting antenna, and directly the CDD channel of equivalent is estimated, and then carried out Data Detection and CQI measurement to the channel response between the receiving antenna array of base station.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 sketch map 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 sketch map of CDD in the prior art;

Fig. 4 is a method flow sketch map provided by the invention;

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

Fig. 6 is a terminal structure sketch map 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 the terminal has many transmit antennas, can adopt circulation delay diversity technology to carry out uplink,, specifically comprise referring to Fig. 4:

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

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

Step 403: the terminal is sent according to the time delay value of confirming and is carried 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, need on different transmit antennas, transmit the CQI pilot tones of different groups this moment, 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 the terminal uses N antenna to receive, and writing down capable Channel Transmission matrix is H ^DL∈ C ^{N * M}Referring to Fig. 5, adaptively selected delay volume is carried out at the terminal and up CDD transmission specifically comprises:

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

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

Here, the terminal utilizes 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, the terminal just can obtain complete down channel transmission matrix H ^DL

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

Here, the terminal utilizes 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: the time delay value when up CDD transmits is confirmed according to the state information of up channel in the terminal;

Here; The terminal directly utilizes the up channel transmission matrix; Confirm the time delay value when up CDD transmits; When promptly confirms

, can utilize the criterion of maximization effective signal-to-noise ratio to carry out confirming of CDD propagation delay time value:

Equivalent channel on the m root antenna on the receiving terminal k number of sub-carrier 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

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 through 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]

The terminal through selecting the corresponding time delay increment size τ ' of maximum effective signal-to-noise ratio, promptly can be confirmed the propagation delay time of each antenna according to formula [1] ${\mathrm{\δ}}_n^{\mathrm{CY}}=\mathrm{N\τ}\′.$

Concrete, in the employed ascending resource piece in terminal, different resource blocks can be used identical CDD delay volume, also can in different resource blocks, use different delay volumes.

If all Resource Block use identical time delay value; K comprises the 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 confirm the propagation delay time value of each antenna for each time delay value increment τ '.

If the time delay value that each Resource Block uses is different; Need to calculate one group of effective signal-to-noise ratio to each Resource Block; In this group effective signal-to-noise ratio, select the corresponding time delay value increment τ ' of maximum effective signal-to-noise ratio then, confirm the delay volume that corresponding Resource Block uses when carrying out uplink according to this time delay value increment τ '.Concrete grammar calculate effective signal-to-noise ratio to certain Resource Block is: 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: upstream data, DM pilot tone and CQI pilot tone are sent according to the CDD propagation delay time value of confirming in the terminal;

After the CDD propagation delay time value of each transmitting antenna is confirmed at the terminal, 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, can also the CQI pilot tone be carried out CDD and handle the back, can adopt following method to confirm 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 that employed each Resource Block uses during the uplink user data transmission is different; The Resource Block that covered of the CQI reference symbol of each user feedback also uses the different time delay value 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, the terminal needed the circulation delay value is informed to the base station through 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 of each Resource Block of terminal is different, the terminal need be informed the corresponding delay value of each Resource Block that the CQI pilot tone occupies to the base station; If all Physical Resource Block in terminal uses identical delay value, the terminal only need be fed back a delay value and got final product so.Such as, can be with the time delay value increment τ that confirms _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, the original pilots data before CDD handles were carried out at pilot signal and terminal that the process CDD that utilization receives handles, carry out channel estimating, carry out data demodulates or channel quality estimation then, and concrete grammar is following:

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) representes the reception signal on the k number of sub-carrier, noise and interference on n (k) the expression k number of sub-carrier.According to r (k) and known original pilots P (k); Utilize conventional channel estimation methods can estimate equivalent channel and utilize channel estimation results, can carry out data demodulates or channel quality estimation.

It is thus clear that the present invention can produce following beneficial effect with respect to prior art:

The error probability performance of system can have been improved according to the delay volume of adaptive each antenna of selection of the characteristic of channel in the terminal.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 confirmed by the 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 directly the CDD channel of equivalent is estimated, thereby carries out Data Detection and CQI measurement.

In addition, can also save the signaling consumption that sends each antenna delay volume to base station receiver.The 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 said down channel, confirm self each transmitting antenna employed time delay value when the uplink cycle delay diversity transmits; According to said time delay value, on self each transmitting antenna, carry out uplink.

This terminal comprises receiving element 601, confirms unit 602 and transmission unit 603 that 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; Confirm unit 602, be used for state information, confirm each transmitting antenna of terminal employed time delay value when the uplink cycle delay diversity transmits according to said down channel; Transmission unit 603 is used for according to said time delay value, on each transmitting antenna of terminal, carries out uplink.

Confirm that 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 said downlink channel condition information, obtain the up channel transmission matrix, this up channel transmission matrix is the transposed matrix of said down channel transmission matrix; Delay value unit 6022 is used to utilize said up channel transmission matrix, confirms 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; When being used at said terminal that employed ascending resource piece uses identical time delay value when the uplink cycle delay diversity transmits,, confirm the effective signal-to-noise ratio that this time delay value increment is corresponding to said each time delay value increment; The method of confirming is: for the subcarrier in said each ascending resource piece; Utilize maximization effective signal-to-noise ratio mapping method,, obtain the corresponding effective signal-to-noise ratio of this time delay value increment according to said time delay value increment and said 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 confirming that according to this time delay value increment each transmitting antenna at said terminal circulates the delay diversity transmission.Second computing unit 60223; When being used at said terminal that employed ascending resource piece uses different time delay values when the uplink cycle delay diversity transmits; For said each ascending resource piece, employed time delay value when each transmitting antenna of confirming said terminal utilizes this ascending resource piece to circulate the delay diversity transmission, the method for confirming is: to said each time delay value increment; For the subcarrier in the said ascending resource piece; Utilize maximization effective signal-to-noise ratio mapping method,, obtain the corresponding effective signal-to-noise ratio of this time delay value increment according to time delay value increment and said 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 confirming that according to this time delay value increment each transmitting antenna at said terminal utilizes said ascending resource piece to circulate the delay diversity transmission.

Transmission unit 603 is used for: use said 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 said 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 at terminal, send mutually orthogonal CQI pilot tone, and said 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, belong within the scope of claim of the present invention and equivalent technologies thereof if of the present invention these are revised with modification, then the present invention also is intended to comprise these changes and modification interior.

Claims (11)

1. the transmission method of upstream multi-antenna in the TDD system, the terminal in the said 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; The state information of said down channel comprises the down channel transmission matrix;

B. said terminal utilizes said down channel transmission matrix, obtains the up channel transmission matrix, and this up channel transmission matrix is the transposed matrix of said down channel transmission matrix; Said terminal utilizes said up channel transmission matrix, confirms self each transmitting antenna employed time delay value when the uplink cycle delay diversity transmits;

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

2. the method for claim 1 is characterized in that, preserves more than one time delay value increment at said terminal, and the employed ascending resource piece in said terminal uses identical time delay value when the uplink cycle delay diversity transmits, and then step B comprises:

To said each time delay value increment; Confirm the effective signal-to-noise ratio that this time delay value increment is corresponding; The method of confirming is: for the subcarrier in said each ascending resource piece; Utilize maximization effective signal-to-noise ratio mapping method,, obtain the corresponding effective signal-to-noise ratio of this time delay value increment according to said time delay value increment and said 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 confirming that according to this time delay value increment each transmitting antenna at said terminal circulates the delay diversity transmission.

3. the method for claim 1 is characterized in that, preserves more than one time delay value increment at said terminal, and the employed ascending resource in the said terminal different time delay value of use when the uplink cycle delay diversity transmit of determining, and then step B comprises:

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

To said each time delay value increment, for the subcarrier in the said ascending resource piece, utilize maximization effective signal-to-noise ratio mapping method, according to time delay value increment and said up channel transmission matrix, obtain the corresponding effective signal-to-noise ratio of this time delay value increment; 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 confirming that according to this time delay value increment each transmitting antenna at said terminal utilizes said ascending resource piece to circulate the delay diversity transmission.

4. like claim 2 or 3 described methods, it is characterized in that step C comprises:

Said time delay value is used at said terminal, 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.

5. method as claimed in claim 4 is characterized in that, this method further comprises:

Said time delay value is used at said terminal, 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.

6. method as claimed in claim 4 is characterized in that, this method further comprises:

Mutually orthogonal CQI pilot tone is sent to the base station in said terminal on each transmitting antenna of self, and said time delay value is fed back to the base station.

7. carry out the terminal that upstream multi-antenna transmits in a TDD system, it is characterized in that this terminal comprises receiving element, confirms unit and transmission unit;

Said 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;

Said definite unit comprises upstream cell and delay value unit; Said upstream cell is used for utilizing the down channel transmission matrix of said downlink channel condition information, obtains the up channel transmission matrix, and this up channel transmission matrix is the transposed matrix of said down channel transmission matrix; Said delay value unit is used to utilize said up channel transmission matrix, confirms each transmitting antenna of terminal employed time delay value when the uplink cycle delay diversity transmits;

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

8. terminal as claimed in claim 7 is characterized in that, said delay value unit comprises:

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

First computing unit; When being used at said terminal that employed ascending resource piece uses identical time delay value when the uplink cycle delay diversity transmits,, confirm the effective signal-to-noise ratio that this time delay value increment is corresponding to said each time delay value increment; The method of confirming is: for the subcarrier in said each ascending resource piece; Utilize maximization effective signal-to-noise ratio mapping method,, obtain the corresponding effective signal-to-noise ratio of this time delay value increment according to said time delay value increment and said 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 confirming that according to this time delay value increment each transmitting antenna at said terminal circulates the delay diversity transmission;

Second computing unit; When being used at said terminal that employed ascending resource piece uses different time delay values when the uplink cycle delay diversity transmits; For said each ascending resource piece, employed time delay value when each transmitting antenna of confirming said terminal utilizes this ascending resource piece to circulate the delay diversity transmission, the method for confirming is: to said each time delay value increment; For the subcarrier in the said ascending resource piece; Utilize maximization effective signal-to-noise ratio mapping method,, obtain the corresponding effective signal-to-noise ratio of this time delay value increment according to time delay value increment and said 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 confirming that according to this time delay value increment each transmitting antenna at said terminal utilizes said ascending resource piece to circulate the delay diversity transmission.

9. terminal as claimed in claim 8 is characterized in that, said transmission unit is used for:

Use said 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.

10. terminal as claimed in claim 9 is characterized in that, said transmission unit also is used for:

Use said 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.

11. terminal as claimed in claim 9 is characterized in that, said transmission unit also is used for:

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

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