CN1792044A - Method and apparatus for allocating channelization codes for wireless communications - Google Patents

Abstract

A data transmission method for a MIMO (Multiple-Input Multiple-Output) system allowing multiple terminals to share channelization codes according to the channel states, by receiving channel information from terminals, allocating channelization codes for each transmit antenna based upon the received channel information, and transmitting data via each transmit antenna according to the allocated channelization codes. When there are many user terminals and if the number of channelization codes are limited, namely, when the total number of channel codes used to distinguish the terminals is less than the total number of terminals, channelization code sharing per transmit antenna among multiple terminals is performed, such that the throughput of data that can be sent by using each channelization code is increased.

Description

Be used to distribute the method and apparatus of the channelization codes of wireless communication system

Technical field

The present invention relates to communication system, especially relate to the method and apparatus that in having the wireless communication system of a plurality of antennas, is used for the assigns channelization code.

Background technology

Because the fast development of wireless communication system is to providing the increase in demand of various types of multimedia services (for example, video, photo, animation, music, recreation etc.) by the wave point of supporting high capacity data transmission and high data rate.Therefore, allow the more crucial of the band-limited method change of more effective use.In order to handle these problems, developed the new data transmission technology of using a plurality of antennas, and so-called " MIMO " (multiple-input and multiple-output) technology is a such example.

Fig. 1 and 2 has shown and has been used for PARC (every day wire rate control) transmitting terminal of mimo system and the structure of receiving terminal.

As shown in Figure 1, the transmitting terminal of mimo system comprises demultiplexer (Demux) 10, the high-speed data-flow of its separation (separating) input is given a plurality of transmitting antennas (Ant1-Antn), code element coding unit 11, it is by producing code element to encoding with each sub-stream of separating of data flow of input, channelization codng unit 12, it distributes to channelization codes (C1-Cn) from the code element of this code element coding unit 11 outputs, adder 13, will be by these channelization codng unit 12 symbols encoded additions, scramble unit 14, it is to the symbol allocation scrambling code (S1-Sn) from these adder 13 outputs, with a plurality of transmitting antennas (Tx1-Txn), its emission is by the code element of these scramble unit 14 expansions.Note the normally identical code of this scrambling code S1-Sn.

This code element coding unit 11 carries out chnnel codings, interweave and map operation producing code element, and also carry out the function of separating the code element that produces.This channelization codng unit 12 is to this symbol allocation channelization codes (C1-Cn) that separates and expand this code element, and the 14 pairs of code elements by the channelization codes expansion of distributing to it in this scramble unit are carried out scramble.

In the prior art, the receiving terminal of this mimo system as shown in Figure 2 comprises interference signal elimination unit 20, it eliminates interference signal from the signal that receives, MMSE detector 21 is carried out MMSE (least mean-square error) linear transformation based on finding to have the signal of maximum SINR (Signal Interference and Noise Ratio) the signal of eliminating unit 20 outputs from this interference signal, de-spread unit 22, it is to the output de-spread of this MMSE detector 21, multiplexer (MUX) 23, the signal of its multiplexed this de-spread, symbol detection unit 24, it handles this multiplex signal, and detect son stream wherein, signal reconstruction unit 25, it will be reconstructed into the form of identical with the signal that receives (or similar) by the sub-stream that this symbol detection unit 24 detects, with signal distribution unit 26, it forms data flow by distributing the sub-stream by these symbol detection unit 24 sequence detection.

This interference signal is eliminated unit 20 and is comprised and being used for from the signal deletion that the receives a plurality of buffers at the son stream of these symbol detection unit 24 reconstruct.This de-spread unit 22 comprises a plurality of Solution Expanders, carries out de-spread by the code that use is distributed to corresponding son stream at this transmitting terminal.

Prior art mimo system with said structure is carried out following operation.

By this demultiplexer 10 is a plurality of son streams that equate with the sum of transmitting antenna with this high-speed data-flow demultiplexing.The sub-bit stream of each demultiplexing experiences channelization code and interweaves and be mapped as code element in this code element coding unit 11.Sum according to channelization codes separates/separates (demultiplexing) once more with corresponding code element.

This channelization codng unit 12 is distributed to code element separately with channelization codes (C1-Cn), and in adder unit 13 code element with channelization codes of distributing to it is added to a code element.This scramble unit 14 is to the symbol allocation scrambling code of output from this adder unit 13, and sends by this transmitting antenna (Tx1-Txn).Usually, the scrambling code of distributing to code element is identical code.

The MMSE detector 21 of this receiving terminal detects the signal with maximum SINR (Signal Interference and Noise Ratio) in the signal that receives by this reception antenna (Rx1-Rxn), and carries out MMSE (least mean-square error) linear transformation.In the output de-spread of 22 pairs of these MMSE detectors 21 in de-spread unit, and this output is combined as a signal at this multiplexer 23.This symbol detection unit 24 detects to detect from the signal by these multiplexer 23 outputs and sends code element, and for carry out inverse mapping and contrary interlace operation as first detection.

This signal reconstruction unit 25 will be reconstructed into the form of received signal by the first sub-stream that this symbol detection unit 24 detects, and export to this interference signal and eliminate unit 20, it eliminates this reconstruction signal from the received signal of storing buffer, export to MMSE detector 21 then.

Therefore, in remaining signal, this MMSE detector 21 is carried out MMSE (least mean-square error) linear transformation on the signal with maximum SINR (Signal Interference and Noise Ratio), and this de-spread unit 22 and this multiplexer 23 is passed through in the output of this MMSE detector 21, and is input in the symbol detection unit 24 that detects the second son stream.

The second son stream that these signal reconstruction unit 25 reconstruct are detected by this stream detecting unit 24, and export to this interference signal cancellation unit 20, it eliminates the signal of this reconstruct from the signal of storing buffer, and export to this MMSE detector 20.Then, repeat the program of above-mentioned explanation, so that this symbol detection unit 24 sequentially detects son stream.

Therefore, when this symbol detection unit 24 detects all son streams, distribute a plurality of son streams that detect to be used for individual traffic by this signal distribution unit 26.

Below, will explain in more detail in the method for transmitting terminal to this transmission symbol allocation channelization codes.

Fig. 3 is the flow chart that is presented at according to channelizing distribution method in the mobile communication system of prior art.

Usually, when sending a given data to a plurality of terminals (for example, subscriber equipment) (UE1-UE8) time, first pilot signal transmitted is used for each terminal initial synchronous.This terminal (UE1-UE8) receives the pilot signal of the state that relates to each transmitting antenna and each reception link, and to base station transmitting channel quality information (CQI).At this, this CQI can be, for example, and " sending reasonable bit number " (transmit possible bit number), that is, and the bit number that is used for each transmitting antenna (bps/Hz) that sends by each terminal.

According to transmitting antenna, MSC (modulation code collection) is selected in the base station that receives CQI information from this terminal from this CQI information, for support high data rate can to each terminal send this MSC (S10, S11).Then, with respect to all antennas, this is base station selected to have the terminal that height " sends reasonable bit number ", and to the terminal distribution channelization codes of selecting (S12).That is, with the code element (S13) of the terminal of distributing to the selection that will send of channelization codes order.

Fig. 4 has shown when having 4 transmitting antennas, 8 users and 4 channelization codes, the example of assigns channelization code.

As shown in Figure 4, " send reasonable bit number " for the UE1 maximum because suppose maximum, and for the UE2 minimum, promptly, according to " sending reasonable bit number " size sequence be UE1＞UE3＞UE8＞UE7＞UE6＞UE4 (=UE5)＞UE2, this base station is distributed C1, C2, C3 and C4 each code element to UE1, UE3, UE5 and UE6 respectively by 4 transmitting antennas (Txl-Tx4) orders, and for remaining terminal (UE2, UE4, UE5 and UE6) assigns channelization code not.

When the branch timing of finishing channelization codes, the base station is carried out multiplexed to the code element of terminal with channelization codes of distributing to it, and by each transmitting antenna (Tx1-Tx4) send (S14, S15).

Usually, for sending and receiving terminal uses the mimo system of a plurality of antennas, the channel quality that is used for each transmitting antenna is different.Therefore, even think that the link-quality between base station and terminal is good, and in fact, can think that some link is very good, and can think that other links are very bad.In this case, the link circuit self-adapting program, the modulator approach (as QAM (quadrature amplitude modulation)) that is used to provide higher as AMC (adaptive modulation and coding) is so that maximum system throughput.

When many users received business simultaneously in mimo system, this base station used channelization codes to distinguish each user.Yet, if the sum of channelization codes less than user's sum, and uses the channelization code allocation method of prior art, there is a kind of situation, wherein can not effectively use limited channel resource.That is, as shown in Figure 4, when having 8 users and using 4 channelization codes, then do not distribute to any channelization codes of some terminal (that is, UE2, UE4, UE5 and UE6), and therefore utilize the efficient of channel resource by undesirable reduction.This is that (that is, channel status or situation) carries out the distribution of channelization codes because the channelization code allocation method of prior art is by determining maximum " to send reasonable bit number " for each antenna.

In addition, according to prior art, if think when the quality of the link between base station and terminal all is abominable (, when some links between send/receive antenna are good, and other links are bad), use low MCS (modulation and coded set) or do not send data flow for these channels of distributing to bad link.Therefore, the efficient that channel uses is lowered, and in fact, detects performance in the data flow of receiving terminal and is lowered.

The present invention also relates in MIMO (multiple-input and multiple-output) wireless communication system, send signal to allow more effective use resource.

Use the transmission method of aerial signal treatment technology can be categorized as open loop process and closed loop procedure.This open loop process is to implement the method that code is used technology and diversity antenna technology again, and travelling carriage does not need to provide to the base station feedback of channel information thus.This closed loop procedure is used by the weighted information that is used for a plurality of antennas (W) that utilizes channel information to obtain, and this channel information is in the receiving terminal measurement and from the receiving terminal feedback, and for the signal that will send, corresponding weighted value is used for each antenna.

This MSB (multi-flow beam formation) or PSRC (each flow rate control) mimo system is a kind of FDD (Frequency Division Duplexing (FDD)) type closed-loop MIMO system.

Fig. 7 has described the MSB mimo system structure according to prior art.This transmitting terminal 710 comprises the dequantisation unit 711 of reception sources data bit; Modulating unit 713, it carries out modulation allocation to each code element that sends from this dequantisation unit 711, and receives feedback from this receiving terminal (explained later); Weight vector multiplier 715, the code element of each modulation allocation that it will send from this modulating unit 713 multiply by weight vector, and receives feedback from this receiving terminal (explained later); And a plurality of transmitting antennas (Tx1 to TxM), it allows signal to transmit by mimo channel.

This transmitting terminal is by being considered the size of each characteristic value by the eigen decomposition of receiving terminal estimated channel matrix.For these channel regions with big relatively characteristic value, use high order modulation approach (as 64QAM, 16QAM etc.), and for these channel regions with relatively little characteristic value, application low-order-modulated method (as, BPSK, QPSK etc.).In order to keep the independence of the code element that sends by different separately data flow, the eigenvector of channel matrix be multiply by this code element respectively, send then.

Promptly, identical modulator approach is not used in all code elements that send by each transport stream, but receives the feedback of channel conditions (that is, state or the situation) conduct of this transmitting terminal from this terminal, and, use suitable modulator approach for each stream according to channel conditions.At this, be appreciated that in order to be identified for the modulator approach of each reception antenna, this receiving terminal need with the identical algorithm that uses at this transmitting terminal.

And, for the code element that sends in different separately modes by each stream, the eigenvector that the eigen decomposition by channel matrix obtains multiplies each other with this code element respectively, and sends, it allows the channel region correlation to be utilized maximum, and keeps the independence in the transport stream.

Less than the relatively little channel region of particular value, do not send code element for having eigenvalue (eigen decomposition by channel matrix obtains), to prevent producing wrong possibility at receiving terminal for the code element that sends from this transmitting terminal.

Even so, high order modulation is used to have the stream of good channel conditions because code element is assigned with, and the total number of bits that sends by all transmitting antennas has increased, and helps the increase of throughput thus.Therefore, prevent (shifting to an earlier date) code element transmission in the channel region that the eigenvector that has little eigenvalue by use produces, can improve the integrated communication quality, in any case the code element transmission will be useless thus by making this transmitting terminal.

As shown in Figure 7, to have transmitting antenna and quantity that quantity is M be the reception antenna of N to this MSB mimo system.If

$\underset{\‾}{\underset{\‾}{H}}$

Relate to this channel matrix, wherein by (differently sending respectively by M transmitting antenna), this receiving terminal is estimated this channel matrix to signal phasor before receiving terminal is received

$\left(\underset{\‾}{\underset{\‾}{H}}\right),$

And send to transmitting terminal by feedback, obtain each eigenvalue and eigenvector value by the eigen decomposition of carrying out at receiving terminal.In other words, this eigenvalue relatively, and if this transmission and receiving terminal have predefined modulator approach allocation table, the index value corresponding to this modulator approach (also being stored in table) that then will be used for each stream can feed back to transmitting terminal.

As shown in Figure 7, this receiving terminal 720 comprises a plurality of reception antennas (Rxl to RxN), and it is by the signal of mimo channel reception from this transmitting terminal 710; Detecting unit 721, it is by use forcing to make zero or the MMSE method is handled the signal of this reception; Conjugation multiplication unit 723, it multiplies each other conjugate (weighing vector that multiplies each other at transmitting terminal 710) and code element from these detecting unit 721 outputs: demodulating unit 725, demodulation is carried out in its modulation of distributing to this code element by use; With multiplexed unit 727, it carries out multiplexed with output reception data.And, also comprising channel estimator 722, it also receives from the signal of this reception antenna (Rxl to RxN) and eigen decomposition unit 724, and it handles the output of this channel estimator 722, and this result is fed back to transmitting terminal 710.At this, give this weighing vector multiplier 715 with this eigenvector feedback information, and give this modulating unit 713 this eigenvalue feedback information.

This receiving terminal forms by carry out wave beam on each code element, and by using make zero technology or MMSE technology of generally well-known pressure to estimate (deductions) signal vector in this transmitting terminal generation.Then, the conjugate of this weighing vector (multiply by each code element at transmitting terminal) multiplies each other with this signal vector, to obtain (detection) each code element.After this, modulate the code element that sends by each transmitting antenna, determine thus from the bit of this transmitting terminal transmission, and carry out the bit stream that multiplication sends from this transmitting terminal with reconstruct according to corresponding modulator approach.

For the MSB mimo system of prior art, can summarize the method that each code element is formed wave beam by following equation (1):

$\underset{\&OverBar;}{S}=\underset{\&OverBar;}{w_1}{\mathrm{<figure-callout\; id="1"\; label="s"\; filenames="A20048001321800251.png,A20048001321800281.png"\; state="\{\{state\}\}">s</figure-callout>}}_1+{\underset{\&OverBar;}{w}}_2{\mathrm{<figure-callout\; id="2"\; label="s"\; filenames="A20048001321800281.png,A20048001321800321.png"\; state="\{\{state\}\}">s</figure-callout>}}_2+L{\underset{\&OverBar;}{w}}_M{s}_M---\left(1\right)$

At this,

Be meant at the wave beam that is used for each code element to form the weighing vector that uses, S is to S _MBe meant data symbols, and SBe meant the signal vector after carrying out wave beam formation for each code element.From individual bit stream, constitute code element S ₁... S _MIn each code element, this individual bit stream is to export from quantity is the absolute coding piece of M.

Do not use the code element of identical modulator approach modulation from each transmission antennas transmit, but receive the feedback of channel conditions (state) the information conduct of each antenna, and carry out modulation by the modulator approach of determining according to each channel status respectively from this terminal.

Therefore, for the code element that runs through equation (1), the different separately modulation of the relatively eigenvalue of this channel matrix, and use.That is, decompose, high order modulation is distributed to these streams with high relatively eigenvalue, and low-order-modulated is distributed to these streams with low relatively eigenvalue based on the local oscillator of carrying out this channel matrix.At this, suppose to multiply each other, and for after this other streams corresponding to the eigenvector of dominant eigenvalue and stream with subscript 1, according to the size order of this eigenvalue, the multiplying each other of eigenvector order with it.

The method that is used to obtain the weighing vector that multiplies each other with each code element can be summarized as follows.

If

$\underset{\&OverBar;}{\underset{\&OverBar;}{H}}$

Be meant channel matrix, signal phasor (sending) process before receiving terminal receives wherein by M transmitting antenna is different, and if this receiving terminal have N reception antenna, this channel matrix is the N*M matrix.If pilot frequency code element (this transmission and receiving terminal have been known) or the pilot channel that separates are from each antenna transmission of this transmitting terminal, then each component of this this channel matrix of receiving terminal deducibility.

For this channel matrix

$\underset{\&OverBar;}{\underset{\&OverBar;}{H}}$

This receiving terminal is carried out eigen decomposition.In this system because hypothesis in the quantity of transmitting terminal antenna in this antenna array greater than antenna amount at this receiving terminal, this channel matrix

$\underset{\&OverBar;}{\underset{\&OverBar;}{H}}$

Not square formation, and therefore can not carry out eigen decomposition, replace thus carrying out at this channel matrix itself

Eigen decomposition.

${\underset{\&OverBar;}{\underset{\&OverBar;}{H}}}^H\underset{\&OverBar;}{\underset{\&OverBar;}{H}}\&DoubleRightArrow;{\mathrm{\&lambda;}}_1{\underset{\&OverBar;}{e}}_1+{\mathrm{\&lambda;}}_2{\underset{\&OverBar;}{e}}_2+L+{\mathrm{\&lambda;}}_M{\underset{\&OverBar;}{e}}_M---\left(2\right)$

At this, H is meant that Hermite calculates λ _MBe meant this matrix Eigenvalue, and e _MBe meant eigenvector.

Usually, when according to the quantity at the antenna of transmitting terminal, when this transmitting terminal sent code element fully, because each eigenvector keeps orthogonal property, this signal can multiply each other by independently weighing vector and each code element and send.

As in equation (1), if form and send signal based on carry out wave beam on each code element, then this receiving terminal is carried out following signal processing.Since will be independently weighing vector and each code element back transmission signal that multiplies each other, by utilizing generally well-known pressure to make zero or the MMSE method can be derived S, and at transmitting terminal weighing vector and each code element are multiplied each other and to be used to send signal from transmitting terminal, the signal that is received by this receiving terminal can be expressed as equation (3) thus

$\underset{\&OverBar;}{R}=\underset{\&OverBar;}{\underset{\&OverBar;}{H}}\underset{\&OverBar;}{S}+\underset{\&OverBar;}{n}---\left(3\right)$

Wherein, nBe meant AWGN (additive white Gaussian noise).

If by the signal vector of use forcing to make zero weighing vector and each code element being multiplied each other and send SBe derived as signal vector This signal vector can be expressed as equation (4):

$\underset{\&OverBar;}{\overset{^}{S}}={\left[{\underset{\&OverBar;}{\underset{\&OverBar;}{H}}}^H\underset{\&OverBar;}{\underset{\&OverBar;}{H}}\right]}^{-1}{\underset{\&OverBar;}{\underset{\&OverBar;}{H}}}^H\underset{\&OverBar;}{R}---\left(4\right)$

If by the signal vector that uses MMSE that weighing vector and each code element are multiplied each other and send SBe derived as signal vector This signal vector can be expressed as equation (5):

$\underset{\&OverBar;}{\overset{^}{S}}={\left[\mathrm{\&alpha;}\underset{\&OverBar;}{\underset{\&OverBar;}{I}}{+\underset{\&OverBar;}{\underset{\&OverBar;}{H}}}^H\underset{\&OverBar;}{\underset{\&OverBar;}{H}}\right]}^{-1}{\underset{\&OverBar;}{\underset{\&OverBar;}{H}}}^H\underset{\&OverBar;}{R}---\left(5\right)$

At this, α additive signal interference-to-noise ratio, and

Be meant unit matrix.If by use forcing to make zero or the MMSE method is derived as signal vector with weighing vector and each code element signal vector S that sends that multiplies each other

And the signal vector of the conjugate of this weighing vector (multiply each other with each code element and send from this transmitting terminal) with this derivation multiplied each other, so that the code element S that can derive and send from this transmitting terminal ₁To S _MTo obtain the code element of this derivation

Extremely

It can be expressed as equation (6):

${\hat{s}}_1={\underset{\&OverBar;}{w}}_1^H\underset{\&OverBar;}{\overset{^}{S}}......\widehat{s_m}={{\underset{\&OverBar;}{w}}_M}^H\underset{\&OverBar;}{\overset{^}{S}}---\left(6\right)$

Modulate the code element of this derivation then according to their modulator approaches separately

Extremely

So that before distributing to each code element, can determine bit.And, after the bit of code element passes through each antenna transmission, determine from the bit stream of this transmitting terminal transmission by multiplexed.

When each transmitting antenna sends different separately code elements, except transmitting based on eigenvector (channel matrix) and each code element are multiplied each other, what this receiving terminal was also relative will compare by the eigenvalue (channel matrix) that eigen decomposition obtains, so that consider the channel status (situation) of each antenna, the modulator approach that is used for determining chnnel coding and passes through the code element of each antenna transmission.

In order to obtain weighing vector, this weighing vector multiplies each other with the code element that independently sends from each transmitting antenna, must carry out the eigen decomposition of the channel matrix of deriving at receiving terminal.At this, do not need extra calculating, because can obtain eigenvalue and eigenvector together by eigen decomposition.

That is, do not use identical modulator approach, still receive each channel region state as feedback from this terminal to the code element that sends from each transmitting antenna, and according to the suitable modulator approach that is used for determining based on each stream of channel status use.Like this, by relatively being used for the S of equation (1) ₁To S _MThe eigenvalue of channel matrix, use different separately modulator approaches.

Therefore, decompose, high order modulation is distributed to these streams with high relatively eigenvalue, and low-order-modulated is distributed to these streams with low relatively eigenvalue based on the local oscillator of carrying out channel matrix.

Certainly, determining in each stream behind the channel coding method and modulator approach with the code element that is sent out, by using the independent beam of carrying out each code element as the eigenvector at the channel matrix that receiving terminal obtains of weighing vector not change in forming.At this, the method for determining to distribute to the modulation of each antenna and encoding scheme (MCS) is as follows.

Use the eigenvalue that obtains by the eigen decomposition shown in the equation (2) to determine to distribute to the modulator approach of each stream, at first determine the corresponding of each eigenvalue than (λ ₁: λ ₂: L: λ _M) (respective ratio).

By these ratios, if smallest eigen less than threshold value, does not send code element in the channel region that is produced by corresponding eigenvector.For next smallest eigen, use low order MCS (modulation and coded set), and high-order MCS is used for dominant eigenvalue.For middle eigenvalue, based on this value relatively, use scala media MCS.

Then, after the channel status different by emulation testing (situation) confirmed, the modulation allocation table can be used for selecting being suitable for the modulation and the coded combination of the requirement of this channel status.

Yet, when a plurality of terminals receive business in prior art MSB mimo system, use channelization codes to distinguish this terminal.Can distinguish a plurality of data flow that send simultaneously by a terminal by the orthogonal property of eigenvector.

Fig. 8 has described a table and has received business simultaneously to explain when a plurality of terminals, and the quantity of channelization codes is during less than number of terminals, the method for distributing radio resource in the prior art mimo system.It has shown an example, wherein has 8 terminals and uses 4 channelization codes.At this, have only terminal 1,3,7 and 8 to be assigned channelization codes and can communicate by letter, and terminal 2,4,5 and 6 does not have assigns channelization code (although having available radio resources), and can not communicate by letter thus.

As shown in Figure 8, if the quantity of the channelization codes in the prior art mimo system less than the quantity of terminal owing to lack channelization codes, can not allocation of channel resources may, although there is available channel resource.

And, the quality of getting rid of when all channel links between base station and a plurality of terminal is good situation, promptly, when some transmitting channel links are good, and other are when being bad, do not send the data flow of distributing to bad link, perhaps, can not effectively utilize channel resource thus by using low order MCS (modulation and encoding scheme) to send data flow.

Summary of the invention

Therefore, an object of the present invention is to provide a kind of apparatus and method that are used at mobile communication system assigns channelization code, it can strengthen the symbol detection ability of receiving terminal.

Second purpose of the present invention provides a kind of apparatus and method that are used at mobile communication system assigns channelization code, and it can improve the utilization ratio of limited channel resource.

The 3rd purpose of the present invention provides a kind of apparatus and method that are used at mobile communication system assigns channelization code, and it can allow the user to pass through antenna shared channel code.

The 4th purpose of the present invention provides a kind of apparatus and method that are used at mobile communication system assigns channelization code, and it can increase the throughput of the data that can send by channelization codes.

In order in whole or in part, to realize above-mentioned purpose at least, a kind of transmission method that is used for a plurality of antenna communication systems is provided, this method comprises from the terminal receiving channel information, based on the channel information that receives is each transmitting antenna assigns channelization code, and passes through each antenna transmission data according to the channelization codes of this distribution.

In order in whole or in part, to realize above-mentioned purpose at least, a kind of base station apparatus with a plurality of antennas is provided, this device comprises receiver, it is from the terminal receiving channel information, allocation units, it is each transmitting antenna assigns channelization code based on the channel information that receives, and transmitter, and its channelization codes according to this distribution sends data by each transmitting antenna.

When assigns channelization code in mobile (wireless) communication system, the symbol detection performance that the inventor is used for improving the receiving terminal of mimo system by exploitation is familiar with and has been handled the shortcoming of the above-mentioned explanation of prior art at least.As a result, the efficient of using channel resource can be improved, data throughout can be increased, and according to transmitting antenna, can the shared channel code between the user.

From in broad terms, aspect of the present invention relates to according to the channel quality that transmits and receives between the antenna, is used for the channelization code allocation of each antenna.Can determine this channel quality based on the channel quality information (CQI) that sends from each terminal, and " sending reasonable bit number " of being used for each antenna of each terminal by use can shine upon this CQI.

Receive this channel quality information,, channelization codes is sequentially distributed to each antenna, and carry out transfer of data according to this channel quality information.

And, be used for the signaling method of mimo system by exploitation, inventor's understanding and handled prior art problems is in the method when number of terminals is counted greater than channelization codes, by a plurality of terminal shared channel codes, so that the more efficient use Radio Resource.

Description of drawings

Fig. 1 has described the transmitting terminal of PARC (the wire rate control every day) mimo system according to prior art;

Fig. 2 has described the receiving terminal of PARC (the wire rate control every day) mimo system according to prior art;

Fig. 3 has described to show according to prior art the flow chart of the channelization code allocation method that is used for mobile communication system;

Fig. 4 has described to be used for the example of Fig. 3 assigns channelization code when having four transmitting antennas, eight users and four channelization codes;

Fig. 5 has described to be used for according to the demonstration of the embodiment of the invention flow chart of the channelization code allocation method of mobile communication system;

Fig. 6 has described to be used for the example of Fig. 5 assigns channelization code when having four transmitting antennas, eight users and four channelization codes;

Fig. 7 has described the block diagram according to the mimo system of prior art;

Fig. 8 described according to the mimo system of prior art when the channelization codes number less than number of terminals, and a plurality of terminal is used to explain the form that is used for the wireless resource allocation method when receiving business simultaneously;

Fig. 9 has described the block diagram according to the mimo system of the embodiment of the invention;

Figure 10 described according in the mimo system of the embodiment of the invention when the channelization codes number less than number of terminals, and a plurality of terminal is used to explain the form that is used for the wireless resource allocation method when receiving business simultaneously.

Embodiment

Usually, use in the mimo system of a plurality of antennas in transmission and receiving terminal, the channel quality of each transmitting antenna, promptly, although the overall channel quality of this transmitting antenna is gratifying with respect to certain terminal (user), the channel quality between each antenna and various terminal may not be gratifying.Therefore,, but in fact, may exist some links to be considered to very good, and that other links are thought is abominable even think that the link-quality between base station and terminal is good.

Therefore, unlike the prior art, when the assigns channelization code, prior art is considered " to send reasonable bit number " with respect to the maximum of all antennas, and the invention provides a kind of scheme, when the assigns channelization code, it determines maximum " sending reasonable bit number " for each antenna.

And, according to prior art, in mimo system, when a plurality of users receive business simultaneously, if less than number of users, there is this situation in the quantity of channelization codes, promptly for specific transmitting antenna, not to user's assigns channelization code, although the channel quality of whole transmitting antenna is not gratifying with good channel quality.

Therefore, the invention provides a kind of scheme, wherein according to antenna takes place, can the shared channel code between the user, to allow the limited channelization codes of more effective usage quantity.

Fig. 5 has described to be used for according to the demonstration of the embodiment of the invention flow chart of the channelization code allocation method of mobile communication system.

As shown in Figure 5, when when a plurality of terminals (UE1-UE8) send data (that is, data flow), the base station is pilot signal transmitted at first, is used for the initialization of terminal synchronous.

The terminal (UE1-UE8) that receives this pilot signal is determined the state (situation) of each link between this transmitting antenna (array) and receiving terminal, and sends the CQI data of this link-quality of expression to the base station.At this, can pass through, for example shine upon this CQI data according to the reasonable bit number of the transmission of each transmitting antenna (bps/Hz).

This base station receives the CQI data (S20) that are used for each antenna from this terminal, and the MCS (modulation code collection) that selects to send to each terminal from corresponding C QI (S21).Then, this base station selected antenna, and select to have a plurality of terminals of the bigger reasonable bit number of transmission then, the sum of the terminal of Xuan Zeing equals channelization codes number (S22, S23) thus.After selecting terminal, this base station is to the terminal order ground assigns channelization code of selecting (S24).

Fig. 6 has described when having four transmitting antennas, eight users and four channelization codes, the example of assigns channelization code.

As shown in Figure 6, " send reasonable bit number ", promptly the bit number that can send to terminal UE 1, UE6, UE7 and UE8 by transmitting antenna (Tx1) is 4bps/Hz, and the bit number that can send to terminal UE 3 is 2bps/Hz, and the bit number that can send to terminal UE 5 is 0bps/Hz.

Therefore, if at first select transmitting antenna Tx1, this base station with the terminal of selecting to have big " sending reasonable bit number " (promptly, select UE1, UE6, UE7 and UE8), and channelization codes (C1-C4) will sequentially be distributed to code element, and this code element will send to selected terminal (UE1, UE6, UE7 and UE8).Because like this, when sending code element and use a plurality of channelization codes in to a plurality of terminals (user), this terminal can the shared channel code, and these terminals of sharing identical channelization codes receive and pass through the code element of different antenna transmission separately.

Then, this base station checks whether the assignment of code that is used for respective transmit antenna (Tx1) finishes (S25), if assignment of code is not finished, then repeatedly carry out S23 step afterwards, if and the assignment of code that is used for respective antenna finishes, then check whether there are other any remaining antennas (S26).

If have remaining antenna as the result who checks step, with respect to transmitting antenna Tx2 to Tx4, repeat S22 step afterwards, and do not have remaining antenna as the result who checks step, this base station is multiplexed and send the code element of the terminal of assigns channelization code (S27) by each transmitting antenna (Tx1-Tx4).

Therefore, as shown in Figure 6, if use channelization code allocation method of the present invention, but a large amount of limited channelization codes of terminal usage quantity, because according to each transmitting antenna, a plurality of terminals can the shared channel code, this with use the art methods of certain channelization codes different to certain terminal.Especially, the present invention allows according to transmitting antenna, by user's shared channel code, increases the throughput by the data of using each channelization codes transmission thus.That is, in the prior art, channelization codes C1 can be used for sending the data flow of 48bps/Hz, and the present invention allows identical channelization codes C1 to be used to send the data flow of 58bps/Hz.

According to the present invention, if the sum of channelization codes is less than receiving the necessarily sum of the terminal of business, the data transmission method in MIMO (multiple-input and multiple-output) system allows same channelization code allocation to give more than one terminal.

When by a plurality of terminal shared channel code, be necessary in terminal, to distinguish.Do like this, when having only relative correlation when the weighing vector that multiplies each other with the data flow of terminal, just allow channelization codes to share less than certain threshold level.Therefore, with respect to each terminal, allow else to disturb (effect by code sharing causes), so that can distinguish the data flow in a plurality of terminals from certain level of other-end.

There is M transmitting antenna in this MSB of the present invention (multi-flow beam formation) mimo system hypothesis, each data flow of using identical channelization codes (such as in PARC MSB) is separately encoded, and add CRC (cyclic redundancy check) sign indicating number to it respectively.

Fig. 9 has shown the exemplary configurations according to closed loop MSB mimo system of the present invention.Be appreciated that this structure according to the present invention is identical with the structure of prior art Fig. 7, except extra use control module (for example, multi-user's weighting control device 917), this control unit is considered a plurality of user terminals, and provides appropriate signal to handle.That is, this multi-user's weighting control device 917 receives feedback from this eigen decomposition unit 924, this eigen decomposition unit output eigenvector feedback and eigenvalue feedback.This multi-user's weighting control device 917 is handled this feedback information, and provides output to a plurality of dequantisation unit (911a-911c), this modulating unit 913 and this weighing vector multiplier 915, is used to carry out the distribution method of the present invention that is discussed in more detail below.

Figure 10 has described in the mimo system according to the embodiment of the invention, when the channelization codes number less than number of terminals, and a plurality of terminal is used to explain the form that is used for the wireless resource allocation method when receiving business simultaneously.

As example, there is 8 terminals (that is subscriber equipment: 4 channelization codes sharing UE) and between terminal.

Thus, have only terminal 1,3,7 and 8 to distribute channelization codes and can communicate by letter, and not to terminal 2,4,5 and 6 assigns channelization codes (although having available radio resources), and can not communicate by letter thus.

At this, be to be understood that the data flow that clearly to distinguish the terminal that is used to have channelization codes C1, C2, C3 and C4.That is the data flow 1,2 and 3 of UE1; The data flow 1 of UE2; The data flow 1,2 and 3 of UE3; All use different channelization codes with the data flow 1 of UE6 respectively with 2, can glitch-freely distinguish thus.Yet, for example, the data flow 1,2 of this UE1 with 3 and the data flow 1 of UE4 use identical channelization codes, need the mode that these are distinguished thus.

Because the characteristics of MSB (multi-flow beam formation) technology, the same data stream that the eigenvector attribute by having the respective orthogonal characteristic can distinguishing terminal, that is, and data flow 1,2 and 3.

The eigenvector that is used for the data flow 1 of UE4 does not have the characteristic with the eigenvector quadrature of the data flow 1,2 that is used for UE1 and 3.Therefore, for shared channel code between different terminal (such as UE1 and UE4), and the eigenvector that multiplies each other by the data symbols that channelization code sends between correlation must be lower than certain threshold value.This can represent by following equation (7):

$\underset{\&OverBar;}{S}={{\underset{\&OverBar;}{w}}_1}^1{\mathrm{<figure-callout\; id="1"\; label="s"\; filenames="A20048001321800251.png,A20048001321800281.png"\; state="\{\{state\}\}">s</figure-callout>}}_1^1+{\underset{\&OverBar;}{w}}_2^1{\mathrm{<figure-callout\; id="2"\; label="s"\; filenames="A20048001321800281.png,A20048001321800321.png"\; state="\{\{state\}\}">s</figure-callout>}}_2^1+{\underset{\&OverBar;}{w}}_3^1{\mathrm{<figure-callout\; id="3"\; label="s"\; filenames="A20048001321800281.png,A20048001321800321.png"\; state="\{\{state\}\}">s</figure-callout>}}_3^1+{\underset{\&OverBar;}{w}}_4^1{\mathrm{<figure-callout\; id="4"\; label="s"\; filenames="A20048001321800281.png,A20048001321800321.png"\; state="\{\{state\}\}">s</figure-callout>}}_4^1---\left(7\right)$

At this, w ^k _iBe meant and K ^ThThe i of terminal ^ThThe eigenvector that stream multiplies each other, s ^k _iBe meant from K ^ThThe i of terminal ^ThThe code element that the individual bit miscarriage of independent encoding block output is given birth to, SBe meant the signal vector after carrying out wave beam on each code element forms.That is, because the weighing vector collection of UE1 w ¹ ₁, w ¹ ₂, w ¹ ₃And the weighing vector collection of UE4 w ¹ ₄Between do not have orthogonal property, have only the correlation when among the element of these two set

$(r_{i,1}^{\mathrm{1,4}}={\underset{\&OverBar;}{w}}_i^1\&CenterDot;{\underset{\&OverBar;}{w}}_1^4(i=\mathrm{1,2,3}))$

When being lower than certain threshold value, allow the shared channel code.When representing above-mentioned technology, be used to allow the situation of the weighted value set of a plurality of terminals that channelization codes shares can be expressed as equation (8) in more general mode:

$\{{\underset{\&OverBar;}{w}}_i^k/{\underset{\&OverBar;}{w}}_i^k\&CenterDot;{\underset{\&OverBar;}{w}}_j^l<C_{\mathrm{th}},k=1,...,K,l=1,...,M_k,j=1,...M_l\}---\left(8\right)$

At this, K and i are meant number of terminals, and subscript i, j are meant the index of the eigenvector that is used for each terminal.

As everyone knows, use a plurality of antennas to cause the improvement of message transmission rate increase and communication quality at transmitting terminal and receiving terminal.For professional mimo system is provided to a plurality of terminals (user), if and the limited amount of channelization codes, the invention provides each the transmitting antenna shared channel code in a plurality of terminals, increase so that pass through the throughput of the data of each channelization codes transmission of use.

Therefore, the invention provides a kind of transmission method that is used for a plurality of antenna communication systems, this method comprises from the step of terminal receiving channel information, based on the channelization information that receives, be each transmitting antenna assigns channelization code, and send data by each transmitting antenna according to the channelization codes that distributes.

And, because the present invention can implement at the transmitting terminal of communication system, the invention provides a kind of base station apparatus with a plurality of transmitting antennas, comprise: from the receiver of terminal receiving channel information, and allocation units, it is each transmitting antenna assigns channelization code based on the channel information that receives, and transmitter, and its channelization codes according to this distribution sends data by each transmitting antenna.

As mentioned above, for each antenna, by utilizing the fact different to the channelizing quality of each transmitting antenna, the present invention according to this channel quality (that is the maximum number of the bit that can send) to each transmitting antenna assigns channelization code sequentially.That is, with respect to each antenna, based on the CQI (channel quality information) that sends from terminal, this base station is to the assigns channelization code sequentially of the user with good quality channel status.As result, between a plurality of users, can share this channelization codes, and each user can receive the data that send by different antennae with this mode assigns channelization code.

Therefore, the present invention allows the transmission of code element by using optimum channel, therefore causes comparing with the limited prior art that only is used for a user of channelization codes, can more effective use channel resource.Especially, the present invention allows the channelization codes between a plurality of users to share according to transmitting antenna, causes high data throughput, and by using each channelization codes can send these data.

In addition, only for the purpose of example, the present invention is described with reference to the accompanying drawing that comprises.Those skilled in the art are to be understood that other embodiment of various modification of the present invention and equivalence are possible.Therefore, following claim has defined the scope and the technological essence of technical protection of the present invention.

Claims (20)

1. transmission method that is used for a plurality of antenna communication systems, this method comprises:

From the terminal receiving channel information;

Based on the channel information that receives is each transmitting antenna assigns channelization code; With

Channelization codes according to this distribution passes through each antenna transmission data.

2. the method for claim 1, wherein this channel information is relevant with the bit number of each antenna transmission by each terminal.

3. the method for claim 1, wherein this channel information is with relevant with the quality of channel, situation or the state that are used for transfer of data.

4. the method for claim 1 wherein according to the bit number that can be sent out, is carried out the distribution of channelization codes to a plurality of terminal order ground.

5. method as claimed in claim 4, wherein by to these terminals of the bit that can send maximum quantity assigns channelization code at first, the terminal distribution channelization codes to the bit that can send next maximum quantity comes execution sequence ground to distribute then.

6. method as claimed in claim 4, wherein this distribution causes sharing the individual channel code by a plurality of terminals.

7. method as claimed in claim 1 is wherein carried out reception, distribution and forwarding step in closed-loop MIMO (multiple-input and multiple-output) communication system.

8. method as claimed in claim 7, wherein this mimo system uses MSB (multi-flow beam formation) technology.

9. method as claimed in claim 8, wherein when the quantity of the channelization codes that is used for distinguishing terminal when receiving the quantity of professional terminal, based on this channel status to the identical channelization codes of a plurality of terminal distribution.

1O. method as claimed in claim 9 wherein has only when the correlation of one group of weighted value of the terminal that is used for sharing described channelization codes is lower than certain threshold value, distributes identical channelization codes.

11. the base station apparatus with a plurality of transmitting antennas, this device comprises:

Receiver, it is from the terminal receiving channel information;

Allocation units, it is each transmitting antenna assigns channelization code based on the channel information that receives; With

Transmitter, its channelization codes according to this distribution sends data by each transmitting antenna.

12. device as claimed in claim 11, wherein this channel information is relevant with the bit number of each antenna transmission of passing through each terminal.

13. device as claimed in claim 11, wherein this channel information is relevant with the quality of channel that is used for transfer of data, situation or state.

14. device as claimed in claim 11 wherein according to the bit number that can be sent out, is carried out the distribution of channelization codes to a plurality of terminal order ground.

15. device as claimed in claim 14, wherein by to these terminals of the bit that can send maximum quantity assigns channelization code at first, the terminal distribution channelization codes to the bit that can send next maximum quantity comes execution sequence ground to distribute then.

16. device as claimed in claim 14, wherein this distribution causes sharing the individual channel code by a plurality of terminals.

17. device as claimed in claim 11 is wherein carried out reception, distribution and forwarding step in closed-loop MIMO (multiple-input and multiple-output) communication system.

18. device as claimed in claim 17, wherein this mimo system uses MSB (multi-flow beam formation) or PSRC (wire rate control every day) technology.

19. device as claimed in claim 18, wherein when the quantity of the channelization codes that is used for distinguishing terminal when receiving the quantity of professional terminal, based on this channel status to the identical channelization codes of a plurality of terminal distribution.

20. device as claimed in claim 19 wherein has only when the correlation of one group of weighted value of these terminals that are used for sharing described channelization codes is lower than certain threshold value, distributes identical channelization codes.

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