CN101588223A - Method, device and system for acquiring multiple-input multiple-output channel information - Google Patents

Abstract

The invention provides a method, device and system for acquiring the multiple-input multiple-output (MIMO) channel information. The method mainly includes: receiving the detecting sounding signal transmitted by the terminal, the sounding signal containing the correlativity information of the downstream MIMO channel of the terminal; detecting the sounding signal to acquire the correlativity information containing the downstream MIMO channel of the terminal. in the invention, the base station can detect the sounding signal transmitted by the user terminal to acquire the whole correlativity condition of the downstream MIMO channel of the user terminal, so that the base station can acquire the comprehensive MIMO channel information. Consequently, the base station can self-adapting select the appropriate MIMO technology to transmit according to the channel feature of the downstream MIMO channel.

Description

The acquisition methods of multiple-input multiple-output channel information, device and system

Technical field

The present invention relates to wireless communication technology field, relate in particular to the acquisition methods and the device of a kind of MIMO (Multi-input Multi-output, multiple-input and multiple-output) channel information based on sounding (detection) signal.

Background technology

Along with the development of radio communication, two-forty becomes the development trend of current wireless communication system with high-quality communication.Because conventional single antenna transmitting-receiving communication system can't satisfy the demand of next generation wireless communication system high power capacity and high reliability, and the employing multi-antenna technology can be under the situation that does not increase frequency spectrum resource and transmitting power, promote communication system ground capacity and reliability exponentially, so the MIMO communication system has caused the extensive concern of industry.

OFDM (Orthogonal Frequency Division Multiplexing, OFDM) technology has obtained using widely in wireless communication system with its effective anti-fading characteristic and higher spectrum efficiency.When OFDM technology and MIMO technology are combined, the two technology is brought out the best in each other, have complementary advantages, be known as the key technology of B3G/4G radio communication of future generation by industry.

The MIMO communication system is all used many antennas at transmitting-receiving two-end, and the working method of MIMO communication system can be divided into two classes: open loop approach and closed-loop fashion.So-called open loop approach just is meant that the MIMO transmitter can adopt the MIMO technology under the prerequisite of not knowing mimo channel information, and closed-loop fashion is meant that the MIMO transmitter need transmitting according to mimo channel information self-adapting ground adjustment MIMO.Because closed-loop MIMO can make full use of mimo channel information, so can open up the spatial domain resource of utilizing mimo system to greatest extent, can obtain the performance more excellent than open loop approach.

Because closed-loop fashion need be known user's descending mimo channel information in advance when emission, so generally need the descending mimo channel information of receiving terminal to the transmitting terminal feedback user, and feedback mimo channel informational needs takies the very big expense of system, in actual applications, be the mimo channel information of feedback fraction often, the mimo channel information spinner of this part will comprise:

1) CQI (Channel Quality Indicator, the channel quality identification) value on the transmission subband;

2) RI of mimo channel (Rank Indication, order information);

3) MIMO precoding codebook index information;

4) MIMO days line options etc.

At TDD (the Time Division Duplexing that adopts the MIMO technology, time division duplex) in the system, consider the reciprocity between the transceiver channel, transmission end of base station can come the Uplink MIMO channel of estimating user by the sounding signal that detects user's emission, and replaces estimated result to user's descending mimo channel according to the estimated result of this Uplink MIMO channel.Therefore, the user can realize feedback to descending mimo channel information by emission sounding signal.

The feedback scheme of a kind of mimo channel information based on the sounding signal of the prior art is:

At Wimax (Worldwide Interoperability for Microwave Access, global bridging technology based on inserting of microwave) in the frame structure of TDD system, reserve several sounding signals and launch the sounding signal for the user in sub-frame of uplink, wherein the sounding signal number of Yu Liuing mostly is 8 most.The user is before emission sounding signal, need to obtain in advance the sounding schedule information of base station to this user, this Sounding schedule information is mainly by the displacement information of time-domain position information, frequency domain position information or the sounding sequence of sounding signal, and the transmitting power of sounding signal etc.At the base station end, can estimate user's up mimo channel information by the sounding signal that detects user's emission, further can obtain user's descending mimo channel information.

In realizing process of the present invention, the inventor finds that there are the following problems at least in the above-mentioned prior art:

In above-mentioned Wimax TDD system, as shown in Figure 1, adopt the closed-loop MIMO technology of 4 antennas in base station side, adopt only with a fixing antenna (antenna 1) emission sounding signal in end side.By the sounding signal of terminal emission is estimated, the base station can obtain the mimo channel information of the antenna 1 of terminal, and be unknowable to the mimo channel information of the antenna 2 of terminal, so also can only utilize the mimo channel information of antenna 1 to carry out closed-loop MIMO.Because the mimo channel information that the base station obtains is incomplete, so just there is very big risk in base station side when adopting closed-loop MIMO.

Summary of the invention

Embodiments of the invention provide a kind of acquisition methods, device and system of mimo channel information, are incomplete problems to solve the descending mimo channel information that the base station obtains in the prior art.

A kind of acquisition methods of multiple-input and multiple-output mimo channel information comprises:

The detection sounding signal that receiving terminal sends has comprised the correlation information of the descending mimo channel of terminal in the described sounding signal;

Described sounding signal is detected, obtain the correlation information of the descending mimo channel of the terminal that wherein comprises.

A kind of deriving means of multiple-input and multiple-output mimo channel information comprises:

Signal receiving module is used for the detection sounding signal that receiving terminal sends, and has comprised the correlation information of the descending mimo channel of terminal in the described sounding signal;

Signal detection module is used for the received described sounding signal of described signal receiving module is detected, and obtains the correlation information of the descending mimo channel of the terminal that wherein comprises.

A kind of terminal comprises:

The code book acquisition module, be used for order information according to descending mimo channel, inquire about the code book that mapping relations between the code book of pre-configured order information and sounding signal are obtained the sounding signal, described order information representation the correlation information of descending mimo channel of terminal;

The sounding signal transmitting module, the sounding sets of signals that obtains behind the sounding signal multiplication that is used for the code book of described sounding signal is fed back as vector and needs sends described sounding sets of signals by single antenna.

A kind of system that obtains of multiple-input and multiple-output mimo channel information comprises:

The deriving means of described mimo channel information and described terminal, described terminal sends the detection sounding signal of the correlation information of the descending mimo channel that has comprised terminal to the deriving means of described mimo channel information, the deriving means of described mimo channel information detects described sounding signal, obtains the correlation information of the descending mimo channel of the terminal that wherein comprises.

The technical scheme that is provided by the embodiment of the invention described above as can be seen, the invention process can make the base station detect by the sounding signal that user terminal is sent, obtain the population characteristic valuve implementations of the descending mimo channel of user terminal, the base station is obtained than more comprehensive mimo channel information.

Description of drawings

In order to be illustrated more clearly in the technical scheme of the embodiment of the invention, the accompanying drawing of required use is done to introduce simply in will describing embodiment below, apparently, accompanying drawing in describing below only is some embodiments of the present invention, for those of ordinary skills, under the prerequisite of not paying creative work, can also obtain other accompanying drawing according to these accompanying drawings.

Fig. 1 is that a kind of base station of the prior art adopts 4 antennas to receive the closed-loop MIMO networking schematic diagram of sounding signal, 1 antenna transmission sounding signal of terminal employing;

The process chart of the method that the MIMO based on sounding that Fig. 2 provides for the embodiment of the invention one feeds back;

The process chart of the method that the MIMO based on sounding that Fig. 3 provides for the embodiment of the invention two feeds back;

Fig. 4 contrasts schematic diagram for the sounding sets of signals and the snr gain of existing sounding signal on channel estimating of the neotectonics that the embodiment of the invention two provides;

The process chart of the method that the MIMO based on sounding that Fig. 5 provides for the embodiment of the invention three feeds back;

The deriving means specific implementation structure chart of a kind of mimo channel information that Fig. 6 provides for the embodiment of the invention;

The specific implementation structure chart of the terminal that Fig. 7 provides for the embodiment of the invention.

Embodiment

In embodiments of the present invention, terminal sends the sounding signal of the correlation information of the descending mimo channel comprised terminal to the base station, and the base station is detected described sounding signal, obtains the correlation information of the descending mimo channel of the terminal that wherein comprises.

For ease of understanding, be that example is further explained explanation below in conjunction with accompanying drawing with several specific embodiments, and each embodiment does not constitute the qualification to the embodiment of the invention to the embodiment of the invention.

Embodiment one

The handling process of the method that the MIMO based on sounding that this embodiment provides feeds back comprises following treatment step as shown in Figure 2:

The detection sounding signal that step 21, base station receiving terminal send has comprised the correlation information of the descending mimo channel of terminal in the described sounding signal.

Terminal is according to the order information of descending mimo channel, inquires about the code book that mapping relations between the code book of pre-configured order information and sounding signal are obtained the sounding signal, described order information representation the correlation information of descending mimo channel of terminal.

The sounding sets of signals that obtains behind the sounding signal multiplication of code book as vector and needs feedback of described terminal with described sounding signal, described terminal sends respectively by single antenna after a plurality of sounding signals in the described sounding sets of signals have been added Cyclic Prefix.

The base station receives a plurality of sounding signals that comprise in the sounding sets of signals of above-mentioned terminal transmission respectively by a plurality of antennas.

Step 22, base station are detected described sounding signal, obtain the correlation information of the descending mimo channel of the terminal that wherein comprises.

The base station is detected each sounding signal that each antenna receives, and obtains each sounding signal corresponding channel estimation value;

Each sounding signal corresponding channel estimation value that all antennas are received stack of being correlated with obtains superposition value, obtains the code book of corresponding sounding signal according to described superposition value;

According to the mapping relations between the code book of pre-configured order information of the code book of described sounding signal inquiry and sounding signal, obtain the order information of the descending mimo channel of described terminal.

The order message reflection of the descending mimo channel of above-mentioned terminal the population characteristic valuve implementations of descending mimo channel of terminal, thereby base station side is obtained than more comprehensive mimo channel information, make the base station select the MIMO lift-off technology under the suitable closed-loop fashion adaptively in time according to the channel characteristics of descending mimo channel.

Embodiment two

The handling process of the method that the MIMO based on sounding that this embodiment provides feeds back comprises following treatment step as shown in Figure 3:

The correlation information of the descending mimo channel of the order information representation terminal of step 31, usefulness mimo channel, the mapping relations between the order information of structure mimo channel and the code book of sounding signal.

This embodiment comes the correlation information of the descending mimo channel of quantization means terminal with the order information of mimo channel.Exemplary, adopting 4 reception antennas with terminal is that example describes, and then the order of the descending mimo channel of terminal mostly is 4 most, and wherein, order is that 4 reception antennas of 1 expression all are correlated with between mutually; Order is that 2 expressions have only 2 reception antennas uncorrelated between mutually; Order is that 3 expressions have only 3 reception antennas uncorrelated between mutually; Order is that 4 reception antennas of 4 expressions are all uncorrelated between mutually.

Exemplary, above-mentioned order information 1,2,3 and 4 is quantified as the symbol of 2 bits: 00,01,10 and 11, and the code book of corresponding sounding signal respectively: (1,1), (1 ,-1), (1, j) and (1 ,-j).The order information of above-mentioned mimo channel and the mapping relations between the code book are shown in following table 1.

Table 1:

The order of mimo channel	The order quantization bit of mimo channel	The code book C of sounding signal
			1	00	(1，1)
2	01	(1，-1)
			3	10	(1，j)
4	11	(1，-j)

In actual applications, the corresponding relation of code book in the above-mentioned table 1 and order need not strict be bound.

When the quantity of the reception antenna of terminal during, also adopt the code book of the sounding signal shown in the above-mentioned table 1 to represent the correlation information of the descending mimo channel of terminal less than 4.When the quantity of the reception antenna of terminal during greater than 4, then choose 4 antennas wherein, adopt the code book of the sounding signal shown in the above-mentioned table 1 to represent the correlation information of the descending mimo channel of 4 antennas that this is chosen.

Step 32, terminal are attached to the code book of the sounding signal of the order information correspondence of descending mimo channel on the original sounding signal as precoding codebook, obtain the sounding sets of signals of neotectonics and send to the base station.

Terminal can adopt existing method of estimation to obtain the order information of descending mimo channel, according to the mapping table shown in the above-mentioned table 1 of this order information inquiry, obtains the code book of corresponding sounding signal.

Suppose between the user in the Wimax TDD system it is to share sounding channel, the B of subcarrier family that then adopts between each user by frequency division multiplexing ₁, B ₂... B _UOrthogonal.Suppose that user u takies the B of subcarrier family _u, the sounding pilot tone of employing is P (k), k ∈ B _u, then the original sounding signal based on the OFDM modulation of this user u is: s (n), and n=0,1,2.....N-1, n are the total length of sounding signal.Wherein, $s\left(n\right)=\frac{1}{F}\underset{k=0}{\overset{F-1}{\mathrm{\&Sigma;}}}P\left(k\right)\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="e\; j"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">e</figure-callout>}}^j,$ F is counting of OFDM when modulation IFFT (Inverse Fast FourierTransform, inverse fast Fourier transform), and n is the time-domain sampling point of sounding signal. $j=\sqrt{-1}.$

With the code book of above-mentioned sounding signal precoding codebook as a bivector form, multiply each other with above-mentioned original sounding signal s (n), the sounding sets of signals that obtains neotectonics is: $\left[\begin{array}{c}{s}_1^{\&prime;}\left(n\right)\\ s_2^{\&prime;}\left(n\right)\end{array}\right]=C^T\&CenterDot;s\left(n\right),$ N=0,1,2.....N-1, wherein C ^TTransposition for the codebook vectors of above-mentioned sounding signal.

Comprise two sounding signals in the sounding sets of signals of above-mentioned neotectonics, respectively a character in the code book of corresponding above-mentioned sounding signal.Such as, 1 and-1 in the corresponding code book of difference (1 ,-1).

In addition, in order to overcome the intersymbol interference that multipath fading is introduced, general sounding signal all needs to add Cyclic Prefix before emission, and the length of Cyclic Prefix should be greater than the channel multi-path time delay L of maximum.

In this embodiment, terminal only adopts fixing single-antenna transmission sounding signal (promptly not adopting the transmission sounding signal of antennae polling mode).Terminal sends to the base station respectively by single antenna after two sounding signals in the sounding sets of signals of above-mentioned neotectonics are added Cyclic Prefix respectively.

Each reception antenna of step 33, base station detects each the sounding signal that receives, obtain the estimated information of down channel of each sounding signal of each antenna, comprehensively the comprehensive down channel estimated information on the precoding codebook information of the information acquisition terminal of the down channel of the sounding signal of each antenna and each antenna.

At the base station end, the sounding signal that adopts many antennas receiving terminal to send.Each reception antenna of base station need detect each the sounding signal that receives.Simultaneously, the information of the up channel of each the sounding signal by each sounding signal being estimated obtain each antenna.Then, by the reciprocity of uplink and downlink interchannel in the TDD system, know the descending channel information of terminal.

The concrete testing process of the information of the up channel of each sounding signal of above-mentioned antenna is as follows:

The reception antenna of supposing the base station end is designated i, i=0,1 ..N _r-1, N wherein _rBe total reception antenna number of base station end, then 2 sounding signals receiving of antenna i are:

${\mathrm{<figure-callout\; id="1"\; label="y"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">y</figure-callout>}}_{1,i}\left(n\right)=\underset{p=0}{\overset{p=L-1}{\mathrm{\&Sigma;}}}{\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">h</figure-callout>}}_{1,i}\left(p\right)\&CenterDot;s_1^{\&prime;}(n-p),$ ${\mathrm{<figure-callout\; id="2"\; label="y"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">y</figure-callout>}}_{2,i}\left(n\right)=\underset{p=0}{\overset{p=L-1}{\mathrm{\&Sigma;}}}{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">h</figure-callout>}}_{2,i}\left(p\right)\&CenterDot;s_2^{\&prime;}(n-p),n=\mathrm{0,1,2}...N+L-1.$

H wherein _{1, i}(p), h _{2, i}(p), p=0,1,2...L-1 is the time domain impulse response of antenna i receive channel on 2 sounding signals.

Suppose that 2 sounding signals are adjacent, channel response can approximately equal in the then adjacent sounding signal, so h is arranged _{1, i}(p) ≈ h _{2, i}(p)=h _i(p).Suppose the channel multi-path time delay L of the circulating prefix-length of sounding signal, so to above-mentioned sounding signal y greater than maximum _{1, i}, y _{2, i}After removing Cyclic Prefix, carry out FFT (Fast Fourier Transform, fast Fourier transform) conversion again and obtain:

${\mathrm{<figure-callout\; id="1"\; label="Y"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">Y</figure-callout>}}_{1,i}\left(k\right)=\underset{n=0}{\overset{F-1}{\mathrm{\&Sigma;}}}{e}^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;kn}/F}\&CenterDot;\underset{p=0}{\overset{p=L-1}{\mathrm{\&Sigma;}}}{\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">h</figure-callout>}}_{1,i}\left(p\right)\&CenterDot;s_1^{\&prime;}(n+\mathrm{CP}-p),$

${\mathrm{<figure-callout\; id="2"\; label="Y"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">Y</figure-callout>}}_{2,i}\left(k\right)=\underset{n=0}{\overset{F-1}{\mathrm{\&Sigma;}}}{e}^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;kn}/F}\&CenterDot;\underset{p=0}{\overset{p=L-1}{\mathrm{\&Sigma;}}}{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">h</figure-callout>}}_{2,i}\left(p\right)\&CenterDot;s_2^{\&prime;}(n+\mathrm{CP}-p),k=\mathrm{0,1,2}...F-1$

Then, according to above-mentioned Y _{1, i}(k), Y _{2, i}(k), calculate two sounding signals that antenna i receives respectively the estimated information of corresponding up channel be:

H′ _1，i(k)＝Y _1，i(k)/P(k)，H′ _2，i(k)＝Y _2，i(k)/P(k)，k∈B _u

Because the sounding signal that reception antenna i receives has passed through above-mentioned operation of multiplying each other with precoding codebook, so above-mentioned H ' _{1, i}(k), H ' _{2, i}(k) there is following relation:

$\left[\begin{array}{c}{\mathrm{<figure-callout\; id="1"\; label="H"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">H</figure-callout>}}_{1,i}^{\&prime;}\left(k\right)\\ {\mathrm{<figure-callout\; id="2"\; label="H"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">H</figure-callout>}}_{2,i}^{\&prime;}\left(k\right)\end{array}\right]=C^T\&CenterDot;H_i\left(k\right),k\&Element;B_u$

Wherein $H_i\left(k\right)=\underset{p=0}{\overset{L-1}{\mathrm{\&Sigma;}}}{h}_i\left(p\right)\&CenterDot;e^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;kp}/F},k\&Element;B_u$ It is the frequency domain response of the up channel on the antenna i.Because the uplink and downlink interchannel is reciprocity in the TDD system, so to this frequency domain response H _i(k) estimation just can obtain the descending channel information between the fixing emission single antenna of antenna for base station i and terminal.

To estimate above-mentioned frequency domain response H exactly _i(k), also must be according to above-mentioned Y _{1, i}(k), Y _{2, i}(k) detect above-mentioned precoding codebook, obtain the order information of the descending mimo channel of terminal again according to this precoding codebook.Each the above-mentioned precoding codebook information processing of antenna joint-detection process is as follows:

Above-mentioned H ' with each antenna _{1, i}(k), H ' _{2, i}(k), i=0,1,2...N _r-1 value is carried out after the conjugate multiplication again, and stack obtains: $W=\frac{1}{N_r}\underset{i=0}{\overset{N_r-1}{\mathrm{\&Sigma;}}}\&CenterDot;\underset{k\&Element;{\mathrm{<figure-callout\; id="1"\; label="B\; u\; H"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">B</figure-callout>}}_u}{\mathrm{\&Sigma;}}{H}_{}^{}{}_{1,i}^{\&prime;}\left(k\right)\&CenterDot;\mathrm{conj}\left({\mathrm{<figure-callout\; id="2"\; label="H"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">H</figure-callout>}}_{2,i}^{\&prime;}\left(k\right)\right),$ Wherein, conj (H ' _{2, i}(k)) be H ' _{2, i}(k) coherent element conjugation,

The real part Re (W) of more above-mentioned W and the size of imaginary part Im (W), if Re (W)＞Im (W), and Re (W)＞0, then above-mentioned precoding codebook is C=(1,1), the order information of the descending mimo channel of relevant terminal is 1;

If Re (W)＞Im (W), and Re (W)≤0, then above-mentioned precoding codebook are C=(1 ,-1), the order information of the descending mimo channel of relevant terminal is 2;

If Re (W)≤Im (W), and Im (W)＞0, then above-mentioned precoding codebook are that (1, j), the order information of the descending mimo channel of relevant terminal is 3 to C=;

If Re (W)≤Im (W), and Im (W)≤0, then above-mentioned precoding codebook be C=(1 ,-j), the order information of the descending mimo channel of relevant terminal is 4.

At last, the above-mentioned precoding codebook C by detection obtains calculates above-mentioned frequency domain response H _i(k):

$H_i\left(k\right)=\frac{1}{2}\&CenterDot;\mathrm{conj}\left(C\right)\&CenterDot;\left[\begin{array}{c}{\mathrm{<figure-callout\; id="1"\; label="H"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">H</figure-callout>}}_{1,i}^{\&prime;}\left(k\right)\\ {\mathrm{<figure-callout\; id="2"\; label="H"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">H</figure-callout>}}_{2,i}^{\&prime;}\left(k\right)\end{array}\right]=\frac{1}{2}\&CenterDot;\mathrm{conj}\left(C\right)\&CenterDot;C^T\&CenterDot;H_i\left(k\right),k\&Element;B_u,i=\mathrm{0,1,2}...N_r-1$

Wherein conj (C) is the coherent element conjugation of precoding C, C ^TTransposition for the precoding codebook vector.Because the uplink and downlink interchannel is reciprocity in the TDD system, according to above-mentioned frequency domain response H _i(k) can obtain descending channel information between the fixing emission single antenna of antenna for base station i and terminal.

Because the sounding signal of above-mentioned neotectonics comprises 2 sounding signals, the redundancy of this sounding signal can improve the channel estimating performance of the sounding of base station among this embodiment.Such as, be example with the system emulation parameter list shown in the following table 2:

Table 2: system emulation parameter list

System bandwidth	10M
		FFT counts	1024
Cyclic Prefix	128
		User's multiplex mode	Decimation in frequency (frequency division multiplexing)
Frequency interval	8
		Channel type	The multipath slow fading
The antenna for base station number	2

The sounding sets of signals of above-mentioned neotectonics and the existing sounding signal snr gain contrast schematic diagram on channel estimating as shown in Figure 4, the sounding sets of signals of the above-mentioned neotectonics of adopting among this embodiment on channel estimating with existing sounding signal mutually specific energy bring the snr gain of about 3dB.

In the prior art, adopted multi-antenna technology, can utilize many antenna receiving-sending signals simultaneously, but still adopted only with a fixing antenna emission sounding signal in end side in base station side.

In addition, in current a lot of wireless communication systems (as LTE (Long Term Evolution) TDD system), the reception antenna of terminal also often will be less than number of transmit antennas.So the base station is the reception antenna channel information that is difficult to estimate terminal iff the transmitting antenna that relies on terminal.

Therefore, the base station can only obtain the mimo channel information of antenna of the emission sounding signal of terminal in the prior art, and is unknowable to the mimo channel information of other antenna of terminal.Because the mimo channel information that the base station obtains is incomplete, so just there is very big risk in base station side when adopting closed-loop MIMO.Because for mimo system, when adopting space multiplexing technique, each interchannel is to influence each other, rather than independent of each other.So do not knowing under the correlation situation of all mimo channels, the receptivity of removing to optimize the part mimo channel blindly, effect is often not good, sometimes even can run counter to desire.

This embodiment is by having comprised the correlation information of the descending mimo channel of terminal in the sounding signal that sends in terminal, the base station is detected described sounding signal, obtains the correlation information of the descending mimo channel of the terminal that wherein comprises.Thereby having realized that even terminal is to adopt 1 fixing antenna to send out sounding, the population characteristic valuve implementations of descending mimo channel also can be known in the base station.This channel relevancy information can be used as a reference index of base station like this, is convenient to the switching of base station between each MIMO launch scenario.

On the other hand, the base station is when estimating the sounding signal, and the detection performance of sounding signal also is vital.For the user of cell edge,,, also increased the power consumption of terminal equipment so simultaneously so need improve the detection performance of base station by increasing the sounding transmitting power to the sounding signal because the user can not adopt the multi-antenna technology emission.This embodiment by the structure the sounding sets of signals in comprise a plurality of sounding signals, increased the redundancy of sounding signal, thereby improved the channel estimating performance of the sounding of base station.

Embodiment three

In this embodiment, be to share the sounding channel between the user by the mode of code division multiplexing.The handling process of the method that the MIMO based on sounding that this embodiment provides feeds back comprises following treatment step as shown in Figure 5:

The correlation information of the descending mimo channel of the order information representation terminal of step 51, usefulness mimo channel, the mapping relations between the order information of structure mimo channel and the code book of sounding signal.

This embodiment comes the correlation information of the descending mimo channel of quantization means terminal with the order information of mimo channel.Exemplary, adopting 4 reception antennas with terminal is that example describes, and then the order of the descending mimo channel of terminal mostly is 4 most, and wherein, order is that 4 reception antennas of 1 expression all are correlated with between mutually; Order is that 2 expressions have only 2 reception antennas uncorrelated between mutually; Order is that 3 expressions have only 3 reception antennas uncorrelated between mutually; Order is that 4 reception antennas of 4 expressions are all uncorrelated between mutually.

Exemplary, above-mentioned order information 1,2,3 and 4 is quantified as the symbol of 2 bits: 00,01,10 and 11, and the code book of corresponding sounding signal respectively: (1,1), (1 ,-1), (1, j) and (1 ,-j).The order information of above-mentioned mimo channel and the mapping relations between the code book are shown in following table 3.

Table 3:

The order of I.MIMO channel	The order quantization bit of I.MIMO channel	The code book C of I.sounding signal
			1	II.00	II.(1，1)
2	III.01	III.(1，-1)
			3	IV.10	IV.(1，j)
4	V.11	V.(1，-j)

In actual applications, the corresponding relation of code book in the above-mentioned table 1 and order need not strict be bound.

When the quantity of the reception antenna of terminal during, also adopt the code book of the sounding signal shown in the above-mentioned table 1 to represent the correlation information of the descending mimo channel of terminal less than 4.When the quantity of the reception antenna of terminal during greater than 4, then choose 4 antennas wherein, adopt the code book of the sounding signal shown in the above-mentioned table 1 to represent the correlation information of the descending mimo channel of 4 antennas that this is chosen.

The terminal of step 52, code division multiplexing is attached to the code book of the sounding signal of the order information correspondence of descending mimo channel on the original sounding signal as precoding codebook, obtains the sounding sets of signals of neotectonics and sends to the base station.

Terminal can adopt existing method of estimation to obtain the order information of descending mimo channel, according to the mapping table shown in the above-mentioned table 1 of this order information inquiry, obtains the code book of corresponding sounding signal.

Suppose between the user in the Wimax TDD system it is to share sounding channel, the B of subcarrier family that then adopts between each user by frequency division multiplexing ₁, B ₂... .B _UOrthogonal.Suppose that user u takies the B of subcarrier family _u, the sounding pilot tone of employing is P (k), k ∈ B _u, then the original sounding signal based on the OFDM modulation of this user u is: s (n), and n=0,1,2.....N-1, n are the total length of sounding signal.Wherein, $s\left(n\right)=\frac{1}{F}\underset{k=0}{\overset{F-1}{\mathrm{\&Sigma;}}}P\left(k\right)\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="e\; j"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">e</figure-callout>}}^j,$ F is counting of OFDM when modulation IFFT (Inverse Fast FourierTransform, inverse fast Fourier transform), and n is the time-domain sampling point of sounding signal. $j=\sqrt{-1}.$

With the code book of above-mentioned sounding signal precoding codebook as a bivector form, multiply each other with above-mentioned original sounding signal s (n), the sounding sets of signals that obtains neotectonics is:

$\left[\begin{array}{c}{\mathrm{<figure-callout\; id="1"\; label="s"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">s</figure-callout>}}_1^{\&prime;}\left(n\right)\\ s_2^{\&prime;}\left(n\right)\end{array}\right]=C^T\&CenterDot;s\left(n\right),n=\mathrm{0,1,2}...N-1,$ C wherein ^TTransposition for the codebook vectors of above-mentioned sounding signal.

Comprise two sounding signals in the sounding sets of signals of above-mentioned neotectonics, respectively a character in the code book of corresponding above-mentioned sounding signal.Such as, 1 and-1 in the corresponding code book of difference (1 ,-1).

In addition, in order to overcome the intersymbol interference that multipath fading is introduced, general sounding signal all needs to add Cyclic Prefix before emission, and the length of Cyclic Prefix should be greater than the channel multi-path time delay L of maximum.

In this embodiment, terminal only adopts fixing single-antenna transmission sounding signal (promptly not adopting the transmission sounding signal of antennae polling mode).Terminal sends to the base station respectively by single antenna after two sounding signals in the sounding sets of signals of above-mentioned neotectonics are added Cyclic Prefix respectively.

Each reception antenna of step 53, base station adopts traditional time domain channel estimation technique to detect to each the sounding signal that receives, obtain the estimated information of down channel of each sounding signal of each antenna, comprehensively the comprehensive down channel estimated information on the precoding codebook information of the information acquisition terminal of the down channel of the sounding signal of each antenna and each antenna.

The antenna i of base station end adopts traditional time domain channel estimation technique that this sounding sets of signals is detected after the sounding sets of signals that the terminal that receives above-mentioned code division multiplexing sends, and the time domain channel that obtains antenna i is estimated as: h _{1, i}(n), h _{2, i}(n),, n=0,1 ... F-1, i=0,1,2...N _r-1, wherein F is that N is counted in system's FFT conversion _rIt is the total reception antenna number in base station.Then, according to the cyclic shift amount u of user's code word, time domain extract two sounding signals that this antenna i receives respectively the information of corresponding down channel be: h _{1, i}(n), h _{2, i}(n),, n ∈ A _u, A wherein _uIt is cyclic shift amount u respective channels extracting position.

Because the sounding signal that each reception antenna of base station receives has passed through above-mentioned operation of multiplying each other with precoding codebook, estimate the frequency domain response h of the up channel on each reception antenna exactly _i(n), also must be according to above-mentioned Y _{1, i}(k), Y _{2, i}(k) detect above-mentioned precoding codebook.The processing procedure of the above-mentioned precoding codebook of each antenna joint-detection is as follows:

When adopting during area detecting method, with the frequency domain response h of each antenna uplink channel _{1, i}(n), h _{2, i}(n),, n ∈ A _u, i=0,1,2....N _r-1 value is carried out after the conjugate multiplication again, and stack obtains: $W^{\&prime;}=\frac{1}{N_r}\underset{i=0}{\overset{N_r-1}{\mathrm{\&Sigma;}}}\&CenterDot;\underset{n\&Element;A_{\mathrm{<figure-callout\; id="1"\; label="u\; h"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">u</figure-callout>}}}{\mathrm{\&Sigma;}}{h}_{}{}_{1,i}\left(n\right)\&CenterDot;\mathrm{conj}\left({\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">h</figure-callout>}}_{2,i}\left(n\right)\right),$ Wherein, conj (h _{2, i}(n)) be h _{2, i}(n) coherent element conjugation.

When adopting the frequency domain detection method, with the frequency domain response h of the up channel of each antenna _{1, i}(n), h _{2, i}(n),, n ∈ A _u, i=0,1,2...N _r-1 earlier in the time domain zero padding, and the FFT conversion of ordering through F transforms to frequency domain: ${\mathrm{<figure-callout\; id="1"\; label="H"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">H</figure-callout>}}_{1,i}\left(k\right)=\underset{n=0}{\overset{F-1}{\mathrm{\&Sigma;}}}{\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">h</figure-callout>}}_{1,i}\left(n\right)\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="e\; j"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">e</figure-callout>}}^j,$ ${\mathrm{<figure-callout\; id="1"\; label="H"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">H</figure-callout>}}_{1,i}\left(k\right)=\underset{n=0}{\overset{F-1}{\mathrm{\&Sigma;}}}{\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">h</figure-callout>}}_{1,i}\left(n\right)\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="e\; j"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">e</figure-callout>}}^j,$ ，k＝0，1，2....F-1，i＝0，1，2...N _r-1。Above-mentioned H with each antenna _{1, i}(k), H _{2, i}(k) superpose and obtain: $W=\frac{1}{N_r}\underset{i=0}{\overset{N_r-1}{\mathrm{\&Sigma;}}}\&CenterDot;\underset{k=\mathrm{0,1,2}..F-1_{\mathrm{<figure-callout\; id="1"\; label="u\; H"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">u</figure-callout>}}}{\mathrm{\&Sigma;}}{H}_{}{}_{1,i}\left(k\right)\&CenterDot;\mathrm{conj}\left({\mathrm{<figure-callout\; id="2"\; label="H"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">H</figure-callout>}}_{2,i}\left(k\right)\right).$

The real part Re (W) of the W that area detecting method or frequency domain detection method obtain when more above-mentioned and the size of imaginary part Im (W), if Re (W)＞Im (W), and Re (W)＞0, then above-mentioned precoding codebook is C=(1,1), the order information of the descending mimo channel of relevant terminal is 1;

If Re (W)＞Im (W), and Re (W)≤0, then above-mentioned precoding codebook are C=(1 ,-1), the order information of the descending mimo channel of relevant terminal is 2;

If Re (W)≤Im (W), and Im (W)＞0, then above-mentioned precoding codebook are that (1, j), the order information of the descending mimo channel of relevant terminal is 3 to C=;

If Re (W)≤Im (W), and Im (W)≤0, then above-mentioned precoding codebook be C=(1 ,-j), the order information of the descending mimo channel of relevant terminal is 4.

When adopting during area detecting method,, calculate the time domain impulse response h of the down channel that the sounding signal estimates on reception antenna i by the above-mentioned precoding codebook C that detection obtains _i(n):

$h_i\left(n\right)=\frac{1}{2}\&CenterDot;\mathrm{conj}\left(C\right)\&CenterDot;\left[\begin{array}{c}{\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">h</figure-callout>}}_{1,i}\left(n\right)\\ {\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">h</figure-callout>}}_{2,i}\left(n\right)\end{array}\right]=\frac{1}{2}\&CenterDot;\mathrm{conj}\left(C\right)\&CenterDot;C^T\&CenterDot;h_i\left(n\right),n\&Element;A_u,i=\mathrm{0,1,2}...N_r-1$

Wherein conj (C) is the coherent element conjugation of the code book C that prelists, C ^TTransposition for the precoding codebook vector.

When adopting the frequency domain detection method,, calculate the frequency domain response H of the up channel that the sounding signal estimates on reception antenna i by the above-mentioned precoding codebook C that detection obtains _i(k):

$H_i\left(k\right)=\frac{1}{2}\&CenterDot;\mathrm{conj}\left(C\right)\&CenterDot;\left[\begin{array}{c}{\mathrm{<figure-callout\; id="1"\; label="H"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">H</figure-callout>}}_{1,i}\left(k\right)\\ {\mathrm{<figure-callout\; id="2"\; label="H"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">H</figure-callout>}}_{2,i}\left(k\right)\end{array}\right]=\frac{1}{2}\&CenterDot;\mathrm{conj}\left(C\right)\&CenterDot;C^T\&CenterDot;H_i\left(k\right),k=\mathrm{0,1,2}...F-1,i=\mathrm{0,1,2}...N_r-1$

Wherein conj (C) is the coherent element conjugation of the code book C that prelists, C ^TTransposition for the precoding codebook vector.Because the uplink and downlink interchannel is reciprocity in the TDD system, according to time domain impulse response h _i(n) and frequency domain response H _i(k) can obtain descending channel information between the fixing emission single antenna of antenna for base station i and terminal.

In the prior art, adopted multi-antenna technology, can utilize many antenna receiving-sending signals simultaneously, but still adopted only with a fixing antenna emission sounding signal in end side in base station side.The base station can only obtain the mimo channel information of antenna of the emission sounding signal of terminal, and is unknowable to the mimo channel information of other antenna of terminal.Because the mimo channel information that the base station obtains is incomplete, so just there is very big risk in base station side when adopting closed-loop MIMO.

This embodiment is by having comprised the correlation information of the descending mimo channel of terminal in the sounding signal that sends in terminal, the base station is detected described sounding signal, obtains the correlation information of the descending mimo channel of the terminal that wherein comprises.Thereby having realized that even terminal is to adopt 1 fixing antenna to send out sounding, the population characteristic valuve implementations of descending mimo channel also can be known in the base station.Realized the sounding sets of signals that the terminal of code division multiplexing sends is detected, obtained the information of the up channel of estimating on the population characteristic valuve implementations of descending mimo channel of terminal and each reception antenna.Make the base station select the MIMO lift-off technology under the suitable closed-loop fashion adaptively in time according to the channel characteristics of descending mimo channel.

Embodiment four

The method that the MIMO based on sounding that the foregoing description is described feeds back can be mixed together use with the MIMO feedback scheme of existing terminal.

The method based on the MIMO feedback of sounding that the base station can dispatch that some users use that the embodiment of the invention proposes simultaneously in the sounding zone of same frame is still used existing MIMO feedback scheme and dispatch other users.Indicate by UL_sounding_Command_IE message the sounding schedule information of terminal the base station, in this embodiment, send the sounding signal of the correlation information of the descending mimo channel that comprises terminal by above-mentioned sounding schedule information indicating terminal, exemplary, can utilize the reserved field in the UL_sounding_Command_IE message to come distinguishing terminal need adopt which kind of MIMO feedback scheme.

In above-mentioned UL_sounding_Command_IE message, the description situation of Include additional feedback field is shown in following table 3:

Table 3: additional feedback field description

Include additional feedback	Describe
		0b00	No additional feedback
0b01	The channel coefficients feedback
		0b10	The pilot coefficients feedback
0b11	Message feedback

When Include additional feedback field was changed to 0b01, then indicating terminal allowed to adopt additional feedback, such as, additional feedback down channel coefficient or descending reception pilot tone etc.When Includeadditional feedback=0b01, to the description situation that adopts the channel coefficients additional feedback shown in following table 4:

Table 4: to adopting the description of channel coefficients additional feedback

Exemplary, this embodiment indicates whether to adopt that the embodiment of the invention proposes based on the method for the MIMO feedback of sounding with the reserved field of 2 bits in the above-mentioned table 4.When the base station need that indicating terminal adopts that the embodiment of the invention proposes based on the method for the MIMO feedback of sounding the time, the base station is when being provided with UL_sounding_Command_IE message, except will as existing MIMO feedback scheme, setting the basic configuration parameter of sounding emission, also need include additional feedback field is made as 0b01, promptly indicate the user need adopt the mode of additional feedback, but when specifically describing this includeadditional feedback field, the reserved field of wherein 1 bit is put 1, what show base station scheduling is the method based on the MIMO feedback of sounding that the embodiment of the invention proposes, if still be to adopt original MIMO feedback scheme, then this reservation bit is put 0.

This embodiment has realized being mixed together use with what the foregoing description was described based on the method for the MIMO feedback of sounding and the MIMO feedback scheme of existing terminal.

One of ordinary skill in the art will appreciate that all or part of flow process that realizes in the foregoing description method, be to instruct relevant hardware to finish by computer program, described program can be stored in the computer read/write memory medium, this program can comprise the flow process as the embodiment of above-mentioned each side method when carrying out.Wherein, described storage medium can be magnetic disc, CD, read-only storage memory body (Read-Only Memory, ROM) or at random store memory body (Random Access Memory, RAM) etc.

Embodiment four

The embodiment of the invention also provides a kind of deriving means of mimo channel information, and its specific implementation structure specifically comprises as shown in Figure 6:

Signal receiving module 61 is used for the detection sounding signal that receiving terminal sends, and has comprised the correlation information of the descending mimo channel of terminal in the described sounding signal;

Signal detection module 62 is used for described signal receiving module 41 received described sounding signals are detected, and obtains the correlation information of the descending mimo channel of the terminal that wherein comprises.

Described device can also comprise:

Mapping relations module 63, be used for the mapping relations between the code book of the order information of descending mimo channel of configurating terminal and sounding signal, described order information representation the correlation information of descending mimo channel of terminal, behind the sounding signal multiplication that comprises order information that the code book of described sounding signal is used for need feeding back as vector and terminal, obtain the sounding sets of signals;

Exemplary, adopting 4 reception antennas with terminal is that example describes, and then the order of the descending mimo channel of terminal mostly is 4 most, and wherein, order is that 4 reception antennas of 1 expression all are correlated with between mutually; Order is that 2 expressions have only 2 reception antennas uncorrelated between mutually; Order is that 3 expressions have only 3 reception antennas uncorrelated between mutually; Order is that 4 reception antennas of 4 expressions are all uncorrelated between mutually.

Exemplary, above-mentioned order information 1,2,3 and 4 is quantified as the symbol of 2 bits: 00,01,10 and 11, and the code book of corresponding sounding signal respectively: (1,1), (1 ,-1), (1, j) and (1 ,-j).The order information of above-mentioned mimo channel and the mapping relations between the code book are shown in following table 4.

Table 4:

The order of I.MIMO channel	The order quantization bit of I.MIMO channel	The code book C of I.sounding signal
			1	II.00	II.(1，1)
2	III.01	III.(1，-1)
			3	IV.10	IV.(1，j)
4	V.11	V.(1，-j)

In actual applications, the corresponding relation of code book in the above-mentioned table 4 and order need not strict be bound.

When the quantity of the reception antenna of terminal during, also adopt the code book of the sounding signal shown in the above-mentioned table 1 to represent the correlation information of the descending mimo channel of terminal less than 4.When the quantity of the reception antenna of terminal during greater than 4, then choose 4 antennas wherein, adopt the code book of the sounding signal shown in the above-mentioned table 1 to represent the correlation information of the descending mimo channel of 4 antennas that this is chosen.

Described signal receiving module 61, the described sounding sets of signals that receiving terminal sends.The production process of this sounding sets of signals is as follows: the correlation information of the descending mimo channel of the order information representation terminal of usefulness mimo channel, the mapping relations between the order information of structure mimo channel and the code book of sounding signal.Terminal as precoding codebook, is attached to the code book of the sounding signal of the order information correspondence of descending mimo channel on the original sounding signal, obtains the sounding sets of signals of neotectonics and sends to the base station.

Described device can also comprise:

Indication information sending module 64 is used for sending the sounding schedule information that comprises indication information to terminal, and described indication information is used for the sounding signal that indicating terminal sends the correlation information of the descending mimo channel that comprises terminal.The method based on the MIMO feedback of sounding that the base station can dispatch that some users use that the embodiment of the invention proposes simultaneously in the sounding zone of same frame is still used existing MIMO feedback scheme and dispatch other users.The base station can be indicated by UL_sounding_Command_IE message the sounding schedule information of terminal, send the sounding signal of the correlation information of the descending mimo channel that comprises terminal by above-mentioned sounding schedule information indicating terminal, exemplary, can utilize the reserved field in the UL_sounding_Command_IE message to come distinguishing terminal need adopt which kind of MIMO feedback scheme.

Described signal detection module 62 specifically comprises:

Code book acquisition module 622, each the sounding signal that is used for each antenna is received detects, and obtains each sounding signal corresponding channel estimation value; Each sounding signal corresponding channel estimation value that all antennas are received stack of being correlated with obtains superposition value, obtains the code book of corresponding sounding signal according to described superposition value.

At the base station end, the sounding signal that adopts many antennas receiving terminal to send.Each reception antenna of base station need detect each the sounding signal that receives.Simultaneously, the information of the up channel of each the sounding signal by each sounding signal being estimated obtain each antenna.Then, by the reciprocity of uplink and downlink interchannel in the TDD system, know the descending channel information of terminal.

The concrete testing process of the information of the up channel of each sounding signal of above-mentioned antenna is as follows:

The reception antenna of supposing the base station end is designated i, i=0,1 ..N _r-1, N wherein _rBe total reception antenna number of base station end, then 2 sounding signals receiving of antenna i are:

${\mathrm{<figure-callout\; id="1"\; label="y"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">y</figure-callout>}}_{1,i}\left(n\right)=\underset{p=0}{\overset{p=L-1}{\mathrm{\&Sigma;}}}{\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">h</figure-callout>}}_{1,i}\left(p\right)\&CenterDot;s_1^{\&prime;}(n-p),{\mathrm{<figure-callout\; id="2"\; label="y"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">y</figure-callout>}}_{2,i}\left(n\right)=\underset{p=0}{\overset{p=L-1}{\mathrm{\&Sigma;}}}{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">h</figure-callout>}}_{2,i}\left(p\right)\&CenterDot;s_2^{\&prime;}(n-p),n=\mathrm{0,1,2}...N+L-1.$

H wherein _{1, i}(p), h _{2, i}(p), p=0,1,2...L-1 is the time domain impulse response of antenna i receive channel on 2 sounding signals.

Suppose that 2 sounding signals are adjacent, channel response can approximately equal in the then adjacent sounding signal, so h is arranged _{1, i}(p) ≈ h _{2, i}(p)=h _i(p).Suppose the channel multi-path time delay L of the circulating prefix-length of sounding signal, so to above-mentioned sounding signal y greater than maximum _{1, i}, y _{2, i}After removing Cyclic Prefix, carry out FFT (Fast Fourier Transform, fast Fourier transform) conversion again and obtain:

${\mathrm{<figure-callout\; id="1"\; label="Y"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">Y</figure-callout>}}_{1,i}\left(k\right)=\underset{n=0}{\overset{F-1}{\mathrm{\&Sigma;}}}{e}^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;kn}/F}\&CenterDot;\underset{p=0}{\overset{p=L-1}{\mathrm{\&Sigma;}}}{\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">h</figure-callout>}}_{1,i}\left(p\right)\&CenterDot;s_1^{\&prime;}(n+\mathrm{CP}-p),$

${\mathrm{<figure-callout\; id="2"\; label="Y"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">Y</figure-callout>}}_{2,i}\left(k\right)=\underset{n=0}{\overset{F-1}{\mathrm{\&Sigma;}}}{e}^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;kn}/F}\&CenterDot;\underset{p=0}{\overset{p=L-1}{\mathrm{\&Sigma;}}}{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">h</figure-callout>}}_{2,i}\left(p\right)\&CenterDot;s_2^{\&prime;}(n+\mathrm{CP}-p),k=\mathrm{0,1,2}...F-1$

Then, according to above-mentioned Y _{1, i}(k), Y _{2, i}(k), calculate two sounding signals that antenna i receives respectively the estimated information of corresponding up channel be:

H′ _1，i(k)＝Y _1，i(k)/P(k)，H′ _2，i(k)＝Y _2，i(k)/P(k)，k∈B _u

Because the sounding signal that reception antenna i receives has passed through above-mentioned operation of multiplying each other with precoding codebook, so above-mentioned H ' _{1, i}(k), H ' _{2, i}(k) there is following relation:

$\left[\begin{array}{c}{\mathrm{<figure-callout\; id="1"\; label="H"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">H</figure-callout>}}_{1,i}^{\&prime;}\left(k\right)\\ {\mathrm{<figure-callout\; id="2"\; label="H"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">H</figure-callout>}}_{2,i}^{\&prime;}\left(k\right)\end{array}\right]=C^T\&CenterDot;H_i\left(k\right),k\&Element;B_u$

Wherein $H_i\left(k\right)=\underset{p=0}{\overset{L-1}{\mathrm{\&Sigma;}}}{h}_i\left(p\right)\&CenterDot;e^{-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;kp}/F},k\&Element;B_u$ It is the frequency domain response of the up channel on the antenna i.Because the uplink and downlink interchannel is reciprocity in the TDD system, so to this frequency domain response H _i(k) estimation just can obtain the descending channel information between the fixing emission single antenna of antenna for base station i and terminal.

To estimate above-mentioned frequency domain response H exactly _i(k), also must be according to above-mentioned Y _{1, i}(k), Y _{2, i}(k) detect above-mentioned precoding codebook, obtain the order information of the descending mimo channel of terminal again according to this precoding codebook.Each the above-mentioned precoding codebook information processing of antenna joint-detection process is as follows:

Above-mentioned H ' with each antenna _{1, i}(k), H ' _{2, i}(k), i=0,1,2...N _r-1 value is carried out after the conjugate multiplication again, and stack obtains: $W=\frac{1}{N_r}\underset{i=0}{\overset{N_r-1}{\mathrm{\&Sigma;}}}\&CenterDot;\underset{k\&Element;{\mathrm{<figure-callout\; id="1"\; label="B\; u\; H"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">B</figure-callout>}}_u}{\mathrm{\&Sigma;}}{H}_{}^{}{}_{1,i}^{\&prime;}\left(k\right)\&CenterDot;\mathrm{conj}\left({\mathrm{<figure-callout\; id="2"\; label="H"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">H</figure-callout>}}_{2,i}^{\&prime;}\left(k\right)\right),$ Wherein, conj (H ' _{2, i}(k)) be H ' _{2, i}(k) coherent element conjugation,

The real part Re (W) of more above-mentioned W and the size of imaginary part Im (W), if Re (W)＞Im (W), and Re (W)＞0, then above-mentioned precoding codebook is C=(1,1);

If Re (W)＞Im (W), and Re (W)≤0, then above-mentioned precoding codebook are C=(1 ,-1);

If Re (W)≤Im (W), and Im (W)＞0, then above-mentioned precoding codebook be C=(1, j);

If Re (W)≤Im (W), and Im (W)≤0, then above-mentioned precoding codebook be C=(1 ,-j).

Order information acquisition module 621, the code book that is used for the sounding signal that obtained according to described code book acquisition module, mapping relations between the order information that disposes in the query mappings relationship module and the code book of sounding signal are obtained the order information of the descending mimo channel of described terminal.

Such as, when above-mentioned precoding codebook is C=(1 ,-1), the order information of the descending mimo channel of relevant terminal is 2; When above-mentioned precoding codebook is C=(1 ,-1), the order information of the descending mimo channel of relevant terminal is 2; When above-mentioned precoding codebook is that (1, j), the order information of the descending mimo channel of relevant terminal is 3 to C=; When above-mentioned precoding codebook be C=(1 ,-j), the order information of the descending mimo channel of relevant terminal is 4.

Channel estimating information acquisition module 623, be used for the code book of the sounding signal that the code book acquisition module 422 according to described sounding signal obtained and the channel estimating information of each sounding signal correspondence that each antenna receives, obtain the final channel estimating information on each antenna.

Such as, the above-mentioned precoding codebook C by detection obtains calculates above-mentioned frequency domain response H _i(k):

$H_i\left(k\right)=\frac{1}{2}\&CenterDot;\mathrm{conj}\left(C\right)\&CenterDot;\left[\begin{array}{c}{\mathrm{<figure-callout\; id="1"\; label="H"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">H</figure-callout>}}_{1,i}^{\&prime;}\left(k\right)\\ {\mathrm{<figure-callout\; id="2"\; label="H"\; filenames="A2009100874220033H1.png"\; state="\{\{state\}\}">H</figure-callout>}}_{2,i}^{\&prime;}\left(k\right)\end{array}\right]=\frac{1}{2}\&CenterDot;\mathrm{conj}\left(C\right)\&CenterDot;C^T\&CenterDot;H_i\left(k\right),k\&Element;B_u,i=\mathrm{0,1,2}...N_r-1$

Wherein conj (C) is the coherent element conjugation of precoding C, C ^TTransposition for the precoding codebook vector.Because the uplink and downlink interchannel is reciprocity in the TDD system, according to above-mentioned frequency domain response H _i(k) can obtain descending channel information between the fixing emission single antenna of antenna for base station i and terminal.

The deriving means of above-mentioned mimo channel information can be the base station.

The embodiment of the invention also provides a kind of terminal, and its specific implementation structure specifically comprises as shown in Figure 7:

Code book acquisition module 71, be used for order information according to descending mimo channel, inquire about the code book that mapping relations between the code book of pre-configured order information and sounding signal are obtained the sounding signal, described order information representation the correlation information of descending mimo channel of terminal.

Sounding signal transmitting module 72, the sounding sets of signals that obtains behind the sounding signal multiplication that is used for the code book of described sounding signal is fed back as vector and needs sends described sounding sets of signals by single antenna.

The embodiment of the invention also provides a kind of system that obtains of multiple-input and multiple-output mimo channel information, specifically comprises the deriving means of mimo channel information shown in Figure 6 and terminal shown in Figure 7.Described terminal sends the detection sounding signal of the correlation information of the descending mimo channel that has comprised terminal to the deriving means of described mimo channel information, the deriving means of described mimo channel information detects described sounding signal, obtains the correlation information of the descending mimo channel of the terminal that wherein comprises.

In sum, the invention process can make the base station detect by the sounding signal that user terminal is sent, and obtains the population characteristic valuve implementations of the descending mimo channel of user terminal, and the base station is obtained than more comprehensive mimo channel information.Thereby make the base station can be in time according to the channel characteristics of descending mimo channel, the MIMO technology emission that adaptive selection is suitable really effectively improves those and is in user's receptivity in the cell edge (channel circumstance is complicated and changeable).

The embodiment of the invention is the redundancy by the sounding signal also, improves the channel estimating performance of sounding signal at the base station end, and multipotency improves the 3dB estimated performance, can significantly promote the closed-loop MIMO feedback performance of Wimax TDD system.

The embodiment of the invention can be applied to be positioned at the user terminal of cell edge, under the prerequisite of the sounding transmitting power that does not improve Cell Edge User, can improve the detection performance of base station to the sounding signal of Cell Edge User effectively.

The embodiment of the invention is compatible existing Wimax standard agreement fully, is based on a kind of enhancing technology of existing Wimax standard agreement, so can be mixed together use with the MIMO feedback scheme of existing terminal.As long as rely on the scheduling of base station side just can realize that also do not need existing Wimax standard agreement is made any modification, realizability is strong, the technical sophistication degree is low.

The above; only for the preferable embodiment of the present invention, but protection scope of the present invention is not limited thereto, and anyly is familiar with those skilled in the art in the technical scope that the present invention discloses; the variation that can expect easily or replacement all should be encompassed within protection scope of the present invention.Therefore, protection scope of the present invention should be as the criterion with the protection range of claim.

Claims (13)

1, a kind of acquisition methods of multiple-input and multiple-output mimo channel information is characterized in that, comprising:

The detection sounding signal that receiving terminal sends comprises the correlation information of the descending mimo channel of described terminal in the described sounding signal;

Described sounding signal is detected, obtain the correlation information of the descending mimo channel of the described terminal that described sounding signal comprises.

2, method according to claim 1 is characterized in that, before the detection sounding signal that described receiving terminal sends, also comprises:

Described terminal is according to the order information of descending mimo channel, and the mapping relations between the code book of inquiry order information and sounding signal are obtained the code book of described sounding signal, the correlation information of the descending mimo channel of the described terminal of described order information representation;

The sounding sets of signals that obtains behind the sounding signal multiplication of code book as vector and needs feedback of described terminal with described sounding signal is by the described souding sets of signals of the antenna transmission of described terminal.

3, method according to claim 2 is characterized in that, described described sounding signal is detected, and obtains the correlation information of the descending mimo channel of the described terminal that described sounding signal comprises, and specifically comprises:

Receive the sounding signal that comprises in the described sounding sets of signals respectively by a plurality of antennas, each sounding signal that each antenna is received detects, and obtains each sounding signal corresponding channel estimation value;

Each sounding signal corresponding channel estimation value that all antennas are received stack of being correlated with obtains superposition value, obtains the code book of corresponding sounding signal according to described superposition value;

According to the mapping relations between the code book of pre-configured order information of the code book of described sounding signal inquiry and sounding signal, obtain the order information of the descending mimo channel of described terminal.

4, method according to claim 3 is characterized in that, described method also comprises:

The channel estimating information of each the sounding signal correspondence that receives according to the code book of described sounding signal and each antenna is obtained the comprehensive channel estimating information on each antenna of base station.

5, method according to claim 3 is characterized in that, described each sounding signal that each antenna is received detects, and obtains each sounding signal corresponding channel estimation value, comprising:

After each sounding signal that each antenna is received removes Cyclic Prefix, carry out fast fourier transform again;

If described terminal adopts the mode of frequency division multiplexing to send described souding sets of signals, the subcarrier family shared according to described terminal extracts each sounding signal corresponding channel estimation value that each antenna receives the sounding signal after described fast fourier transform;

Perhaps, if described terminal adopts the mode of code division multiplexing to send described souding sets of signals, cyclic shift amount according to the code word of described terminal extracts each sounding signal corresponding channel estimation value that each antenna receives the sounding signal after described fast fourier transform.

6, method according to claim 1 and 2 is characterized in that, described method also comprises:

Send the sounding schedule information that comprises indication information to described terminal, described indication information is used for the sounding signal that indicating terminal sends the correlation information of the descending mimo channel that comprises terminal.

7, a kind of deriving means of multiple-input and multiple-output mimo channel information is characterized in that, comprising:

Signal receiving module is used for the detection sounding signal that receiving terminal sends, and has comprised the correlation information of the descending mimo channel of terminal in the described sounding signal;

Signal detection module is used for the received described sounding signal of described signal receiving module is detected, and obtains the correlation information of the descending mimo channel of the terminal that wherein comprises.

8, the deriving means of multiple-input and multiple-output mimo channel information according to claim 7 is characterized in that, described device also comprises:

The indication information sending module is used for sending the sounding schedule information that comprises indication information to terminal, and described indication information is used for the sounding signal that indicating terminal sends the correlation information of the descending mimo channel that comprises terminal.

9, according to the deriving means of claim 7 or 8 described multiple-input and multiple-output mimo channel information, it is characterized in that described device also comprises:

The mapping relations module, be used for the mapping relations between the code book of the order information of descending mimo channel of configurating terminal and sounding signal, described order information representation the correlation information of descending mimo channel of terminal, behind the sounding signal multiplication that comprises order information that the code book of described sounding signal is used for need feeding back as vector and terminal, obtain the sounding sets of signals;

Described signal receiving module, the described sounding sets of signals that receiving terminal sends.

10, the deriving means of multiple-input and multiple-output mimo channel information according to claim 9 is characterized in that, described signal detection module specifically comprises:

The code book acquisition module, each the sounding signal that is used for each antenna is received detects, and obtains each sounding signal corresponding channel estimation value; Each sounding signal corresponding channel estimation value that all antennas are received stack of being correlated with obtains superposition value, obtains the code book of corresponding sounding signal according to described superposition value;

Order information acquisition module, the code book that is used for the sounding signal that obtained according to described code book acquisition module, mapping relations between the order information that disposes in the query mappings relationship module and the code book of sounding signal are obtained the order information of the descending mimo channel of described terminal.

11, the deriving means of multiple-input and multiple-output mimo channel information according to claim 10 is characterized in that, described signal detection module also comprises:

Channel estimating information acquisition module, be used for the code book of the sounding signal that obtained according to described code book acquisition module and the channel estimating information of each sounding signal correspondence that each antenna receives, obtain the comprehensive channel estimating information on each antenna of base station.

12, a kind of terminal is characterized in that, comprising:

The code book acquisition module, be used for order information according to descending mimo channel, inquire about the code book that mapping relations between the code book of pre-configured order information and sounding signal are obtained the sounding signal, described order information representation the correlation information of descending mimo channel of terminal;

The sounding signal transmitting module, the sounding sets of signals that obtains behind the sounding signal multiplication that is used for the code book of described sounding signal is fed back as vector and needs sends described sounding sets of signals by single antenna.

13, a kind of system that obtains of multiple-input and multiple-output mimo channel information is characterized in that, comprising:

Deriving means and terminal as claimed in claim 12 as each described mimo channel information of claim 7 to 11, described terminal sends the detection sounding signal of the correlation information of the descending mimo channel that has comprised terminal to the deriving means of described mimo channel information, the deriving means of described mimo channel information detects described sounding signal, obtains the correlation information of the descending mimo channel of the terminal that wherein comprises.

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