CN101568064A - Method and device for multi-user scheduling - Google Patents

Abstract

The invention provides a method for multi-user scheduling, which comprises the following steps: acquiring direction of arrival (DOA) information of all users to be scheduled in a cell; and selecting the users on the basis of the DOA information of all the users to be scheduled in the cell. The invention also provides a device for the multi-user scheduling, which comprises the following units: a DOA acquiring unit for acquiring the DOA information of all the users to be scheduled in the cell; and a user pairing unit for selecting the users on the basis of the DOA information of all the users to be scheduled in the cell. Through the method and the device for the multi-user scheduling, the complexity of the multi-user scheduling in the prior art can be reduced, thus system resources required by the multi-user scheduling are reduced.

Description

A kind of method of multi-subscriber dispatching and device

Technical field

The present invention relates to the RRM field, particularly relate to a kind of method and device of multi-subscriber dispatching.

Background technology

Following mobile communication system develops towards the direction of big bandwidth, high power capacity, high-efficiency, high reliability.Many inputs and many output (Multiple Input Multiple Output, MIMO) technology is as the effective means that improves capacity, be widely used in facing the future in the mobile communication system of design, as Long Term Evolution (LongTime Evolution, LTE), World Interoperability for Microwave Access, WiMax (World Interoperability forMicrowave Access, WIMAX), (Beyond 3G is B3G) etc. in the system for super 3G.And (the Multi-User Multiple Input Multiple Output of the multiuser MIMO in the MIMO technology, MU-MIMO), can be on identical running time-frequency resource multiplexing a plurality of data for the treatment of dispatched users, the dispatched users for the treatment of in the sub-district is dispatched, thereby utilize multi-user diversity, make power system capacity along with the number of transmit antennas linear growth.In MU-MIMO, the quality of multi-user dispatching method has determined performance and the implementation complexity of MU-MIMO to a great extent.A good MU-MIMO multi-user dispatching method can make the interference between the pairing user as much as possible little, better obtains multi-user diversity gain, has lower complexity simultaneously.

In existing system, the most frequently used multi-subscriber dispatching algorithm is to simplify greedy (Greedy) algorithm, and in essence, this algorithm is the multi-user dispatching method of a kind of maximum capacity or minimum interference, uses this method to realize that the process of multi-subscriber dispatching is as follows:

Suppose that there is N root antenna the base station, the MU-MIMO system maximum number of user that can hold is N so.Below, for simplicity, abbreviate the dispatched users for the treatment of in the sub-district as user.

1) base station obtains the downlink channel condition information of user in the jurisdiction district.

This channel condition information perhaps utilizes tdd mode lower channel up-downgoing symmetry by reporting of user, is obtained by base station measurement.

2) initialization dispatched users set.

The base station is according to the downlink channel condition information of user in the sub-district, and the best user of selective channel condition supposes that as main user user's sequence number of selecting is i, and the set of initialization dispatched users is S={i}, calculates the channel capacity C that this user of scheduling separately can obtain _S

3) generate new dispatched users set.

From remaining users, select a user, make:

$j=\underset{k\∈U\backslash i}{\mathrm{agr}\max }{C}_{S\∪\left\{k\right\}}---(1-1)$

Wherein U represents the set of user in the jurisdiction district, base station, U n represent to remove remaining users set behind the nth user, operator A ∪ B represents two union of sets collection, C _{S ∪ { k}}The channel capacity that the new dispatched users that expression dispatched users S set and k dispatched users assemble is gathered.The user's principle of choosing that formula (1-1) is set forth is: calculate the channel capacity of the new dispatched users set of each remaining users and former dispatched users set composition, the channel capacity that makes new dispatched users gather in the remaining users is reached maximum user select into new dispatched users set.

4) whether the channel capacity of the new dispatched users of interpretation set is greater than former dispatched users set.

If:

C _{S ∪ { k}}＞C _S, the channel capacity of promptly new dispatched users set substitutes the original subscriber with new dispatched users set so and dispatches set, be i.e. S=S ∪ { k} greater than the channel capacity of former dispatched users set.

If:

C _{S ∪ { k}}≤ C _SIf the channel capacity of promptly new dispatched users set is not more than the channel capacity of former dispatched users set, so former dispatched users S set remains unchanged.

5) judge whether remaining users in addition.

If no, finish the flow process of multi-subscriber dispatching.

6) judge the big or small L that S gathers.

If L＜N skips to the 3rd) step.

If L=N reaches the maximum number of user that the base station can hold, finish the flow process of multi-subscriber dispatching.

Though prior art can reduce the interference between the user and obtain multi-user diversity gain preferably, but prior art needs the downlink channel quality information of all users in the dispatched users set when the channel capacity of carrying out the dispatched users set is calculated, therefore need the user feedback downlink channel condition information, thereby need the support of control signaling, increased the control signaling consumption of system.And prior art to multi-user's scheduling based on calculation of capacity, and the complexity height of calculation of capacity needs to consume a large amount of system resources in computation.

Summary of the invention

In view of this, main purpose of the present invention is to propose a kind of multi-user dispatching method and device thereof, to solve multi-subscriber dispatching complexity height in the prior art, consumes the problem of a large amount of system resources.

In order to achieve the above object, the method for a kind of multi-subscriber dispatching of the present invention's proposition is:

Obtain the angle of arrival DOA information of the dispatched users that remains in the sub-district;

DOA information based on the dispatched users that remains in the sub-district is chosen the user.

The DOA information of wherein obtaining the dispatched users that remains in the sub-district comprises:

Each treats the up channel impulse response of dispatched users in the measurement sub-district;

According to each treats the space correlation battle array of dispatched users in the up channel impulse response calculation plot;

Each treats the array response vector of dispatched users to the angle of search in the calculation plot;

According to space correlation battle array and array response vector to each treats that dispatched users searches for to obtain DOA information in the sub-district.

Wherein, choosing the user based on the DOA information of the dispatched users that remains in the sub-district comprises:

The set of initialization dispatched users;

Based on the DOA Information Selection user of the dispatched users that remains in the sub-district in the dispatched users set.

Wherein, initialization dispatched users set comprises:

The set of establishment dispatched users;

Select in the sub-district in the dispatched users that remains the best user of down channel quality it is selected into dispatched users gathers as main user.

Wherein, select the best user of down channel quality to comprise as main user:

Receive in the sub-district the quality information of the down channel that feeds back of the dispatched users that remains;

Select the best user of down channel quality as main user according to quality information.

If in tdd systems, select in the sub-district in the dispatched users that remains the best user of down channel quality comprise as main user:

Select in the sub-district in the dispatched users that remains the user of the mould value maximum of up channel impulse response as main user.

Wherein the DOA Information Selection user based on the dispatched users that remains in the sub-district comprises in the dispatched users set:

A, the angle threshold value is set, the set of the dispatched users after the initialization is gathered as current scheduling user;

B, constitute current residual user set after the dispatched users that remains in the sub-district removed user in the current scheduling user set, DOA information and angle threshold value based on the dispatched users that remains in the sub-district are chosen a user in current residual user set, if do not choose the user, stop scheduling flow; If choose a user, the user who chooses is added the current scheduling user set;

C, judge that whether the number of users in the current scheduling user set reaches the described maximum number of user for the treatment of that dispatching cell can hold, if reach, stops scheduling flow; If do not reach, return step b.

Wherein, choosing a user based on the DOA information of the dispatched users that remains in the sub-district and angle threshold value in current residual user set comprises:

User's the angle of arrival was poor during user's the angle of arrival and dispatched users were gathered in the set of calculating remaining users;

If have a user in the remaining users set, make in all users of remaining users set, the difference maximum of user's the angle of arrival in the set of this user's the angle of arrival and dispatched users, and the difference of the angle of arrival that should maximum is greater than the angle thresholding, with the user as a user who chooses.

The present invention also provides a kind of device that is used for multi-subscriber dispatching, and this device comprises:

The DOA acquiring unit is used to obtain the DOA information of the dispatched users that remains in the sub-district;

User pairing unit is used for choosing the user based on the DOA information of the dispatched users that remains in the sub-district.

Wherein user pairing unit comprises:

Initialization module is used for the set of initialization dispatched users;

The user chooses module, and the DOA information of the dispatched users that remains in the sub-district that is used for being obtained based on described DOA information acquisition unit is selected in the dispatched users set that the user creates in the described initialization module.

In sum, a kind of multi-user dispatching method and the device thereof of the present invention's proposition have the following advantages:

The method of the multi-subscriber dispatching that the embodiment of the invention provides is based on user's the angle of arrival.And user's scheduling is based on the channel capacity of dispatched users set in the prior art, and comparatively speaking, the amount of calculation of calculating user's the angle of arrival is more much smaller than the amount of calculation of the channel capacity of calculating user's set.And, in number of users that can hold in the base station and jurisdiction district, the base station coverage during number of users a lot, the amount of calculation that channel capacity produced of calculating the dispatched users set can become very huge, and the advantage of the angle of arrival on amount of calculation based on the user in the embodiment of the invention can be more obvious.

Simultaneously, technical scheme provided by the invention is only being sought the downlink channel quality information that just can use the user when main user gathers with the initialization dispatched users.And all need to use the quality information of down channel during the each calculating channel capacity of prior art.Comparatively speaking, technical scheme provided by the invention has reduced user feedback down channel state number of times, and then has reduced the control signaling consumption of system.

Description of drawings

Fig. 1 is based on the MU-MIMO multi-subscriber dispatching schematic diagram of angle in the embodiment of the invention;

Fig. 2 is a schematic flow sheet of realizing the method for multi-subscriber dispatching in the embodiment of the invention;

Fig. 3 is the schematic flow sheet that obtains the method for DOA information in the embodiment of the invention;

Fig. 4 is the embodiment of the invention is carried out user's method of matching based on the angle of the angle of arrival a schematic flow sheet;

Fig. 5 is a structural representation of realizing the device of multi-subscriber dispatching in the embodiment of the invention.

Embodiment

For making the purpose, technical solutions and advantages of the present invention clearer, the present invention is described in further detail below in conjunction with the accompanying drawings and the specific embodiments.

At the deficiencies in the prior art, a kind of angle of arrival based on the user (Direction Of Arrival, multi-user dispatching method DOA) have been proposed among the present invention.Fig. 1 is based on the MU-MIMO multi-subscriber dispatching schematic diagram of the angle of arrival in the embodiment of the invention.As shown in Figure 1, there are two antennas the base station under the sub-district, can hold two users, and 4 users are arranged in cell coverage area.BS has measured all users' up channel, and calculates all users' DOA.Choose according to carrying out the user then, for example two users of DOA angular separation maximum are dispatched user in the set as the user based on the selection principle of DOA.As shown in Figure 1, this method need be made calculating to the difference of UE1 angle of arrival of per two users in the UE4, and select two users of the difference maximum of the angle of arrival, promptly UE1 and UE4 carry out the MU-MIMO downlink as the user in the dispatched users set to the user in the dispatched users set.Suppose that there is N root antenna the base station, M user arranged in its coverage, in multi-subscriber dispatching, need be based on the angle of arrival to C _M ^NKind of user's combination is calculated and is compared, when the number of M and N is bigger, to user's pairing meeting more complicated.In another embodiment of the present invention, only consider whether satisfy the criterion of setting between the user in the user that is not scheduled and the dispatched users set,, then this user is selected into during dispatched users gathers if satisfy based on the angle of arrival.Make that the amount of calculation when carrying out multi-user's pairing and the number of users M in the base station range are irrelevant in this way, therefore can reduce technical scheme shown in Figure 1 scheduling complexity when M and N are bigger in this way.

In the present invention, suppose: there is N root antenna the base station, and antenna array adopts uniform linear array, and (UniformLinear Array, ULA), bay spacing 0.5 λ, λ are carrier wavelength.Technical scheme of the present invention is described below:

In step 201, obtain the DOA information of all users in the sub-district.

All users' DOA is measured according to the state information of the down channel of all user feedbacks in the jurisdiction district in the base station.When technical scheme that the embodiment of the invention provided is applied in the TDD system, because up channel and down channel have symmetry, therefore the quality of the quality of up channel and down channel can be equal to and treat, the state information that does not need the user feedback down channel, base station are directly according to each user's of mass measurement of up channel DOA.

In step 202, choose the user based on the information of the angle of arrival.

At first, the best user of base station selected down channel quality is as main user, the set of initialization dispatched users.

The dispatched users S set of a sky is at first created in the base station, and according to the downlink channel condition information of all users in the sub-district, the best user of selective channel condition supposes that as main user user's sequence number of selecting is i, upgrade the dispatched users set and be S={i}, the angle of arrival of supposing this user is q _i ^DOA

Then, user's pairing is carried out based on the angle of the angle of arrival in the base station, chooses user in the dispatched users set.

A user is selected in the base station from remaining users, make the angular separation of the user in this user and the dispatched users S set satisfy certain criterion.

If can find such user, suppose that the user's that finds sequence number is j, upgrade the dispatched users set and be S=S ∪ j.

If can not find such user, the dispatched users set remains unchanged so, finishes the flow process of this multi-subscriber dispatching.

Repeat above-mentioned searching user's step, up to not having remaining users or, finishing the flow process of this multi-subscriber dispatching up to the big or small L=N of dispatched users S set.

Below in conjunction with accompanying drawing such scheme is explained in detail.In a specific embodiment of the present invention, suppose that there is N root antenna the base station, antenna array adopts even linear array, bay spacing 0.5 λ.User's set in the jurisdiction district, base station is U, and its size is M.Each user installation has 1 antenna, and employed system is the TDD system.

1) obtains DOA information.

Fig. 3 is a step of obtaining DOA information in the embodiment of the invention.As described in Figure 3, concerning i user, the step of obtaining DOA information is as follows:

In step 301, (Base Station BS) measures all users' up channel impulse response h in the base station _i, i=1 ... M.H wherein _iBe the vector of N * 1, can be according to h _iEstimate all users' up DOA.

If employed system is the FDD system, the h in the step 301 _iShould be the impulse response of the down channel of user feedback.

In step 302, calculate i user's space correlation battle array R according to formula (2-1) _i:

$R_i=E\left\{h_i{h}_i^H\right\}---(2-1)$

In step 303, calculate the angle θ of i user to search _kArray response vector w _kIn the present invention, calculate w according to formula (2-2) _k:

w _k＝[1exp(-j2π0.5sinθ _k)……exp(-j2π(N-1)0.5sinθ _k)] (2-2)

θ wherein _kBe the angle of k search, θ _k∈ A.Shown in formula (2-3), A is the angle set of search:

$A=\{{\mathrm{\θ}}_k=\mathrm{k\Δ}|k=0......\frac{360}{\mathrm{\Δ}}-1\}---(2-3)$

Wherein Δ is the angle searching interval.

In step 304, i user carried out angle searching to obtain the angle of arrival.In the present invention, the prominent angle of aspect of selecting to make the base station receive according to formula (2-4) is user's the angle of arrival.

${\mathrm{\θ}}_i^{\mathrm{DOA}}=\underset{{\mathrm{\θ}}_k\∈A}{\arg \max }{w}_k{R}_i{w}_k^H,i\∈U---(2-4)$

2) select main user.

In the present invention, selecting the user of the mould value maximum of up channel impulse response according to formula (2-5) is main user, and the set of renewal dispatched users is S={u}.

$u=\underset{i=1......M}{\arg \max }{\left|\right|h_i\left|\right|}^2---(2-5)$

3) carry out user pairing, based on user's DOA Information Selection user in the dispatched users set.

Fig. 4 as shown in Figure 4, carries out user's pairing and may further comprise the steps with the flow process of selecting the user for carry out the schematic flow sheet of user's pairing among the present invention based on the angle of the angle of arrival:

In step 401, angle thresholding θ is set ^ThresholdIn the present invention, according to formula (2-6) θ is set ^Threshold:

${\mathrm{\θ}}^{\mathrm{Threshold}}=\arcsin \frac{4}{N}---(2-6)$

In step 402,,, choose a user according to selecting user's principle to carry out user's pairing based on the user's who obtains in the step 304 the angle of arrival.In the present invention, gather from remaining users the base station, promptly U select the user among the S.The criterion of selecting the user is shown in formula (2-7):

$k=\underset{m\∈U\backslash S,n\∈S,|{\mathrm{\θ}}_m^{\mathrm{DOA}}-{\mathrm{\θ}}_n^{\mathrm{DOA}}|>{\mathrm{\θ}}^{\mathrm{Threshold}}}{\arg \max }|{\mathrm{\θ}}_m^{\mathrm{DOA}}-{\mathrm{\θ}}_n^{\mathrm{DOA}}|---(2-7)$

Wherein, m represent remaining users set U a user among the S, n represents a user in the dispatched users set.The criterion of formula (2-7) expression is: user's the angle of arrival was poor during user's the angle of arrival and dispatched users were gathered in the set of calculating remaining users.If have a user m in the remaining users set, make in all users of remaining users set, the difference maximum of user's the angle of arrival in the angle of arrival of user m and the dispatched users set, and the difference of the maximum angle of arrival is then chosen this user m greater than the angle thresholding.

In step 403, judge whether k exists.

If there is k, execution in step 404;

Otherwise, the flow process of end multi-subscriber dispatching.

In step 404, upgrade the dispatched users set, user m is chosen in the dispatched users set:

S＝S∪{k} (2-8)

In step 405, judge whether the size of dispatched users S set reaches the maximum number of user that the sub-district can hold, and promptly whether L=N sets up, if be false, execution in step 402; If set up, finish the flow process of multi-subscriber dispatching.

Based on above method, the invention provides a kind of device of multi-subscriber dispatching, Fig. 5 is the structural representation of this device.As shown in Figure 5, this device comprises with lower unit:

DOA acquiring unit 510 is used to obtain the DOA information of all users in the sub-district.

User pairing unit 520 is used for all users' of obtaining based on DOA information acquisition unit 510 DOA information and chooses the user.

Wherein user pairing unit 520 comprises initialization module 521, is used for the set of initialization dispatched users.The user chooses module 522, is used for all users' of being obtained based on DOA information acquisition unit 510 DOA information, selects in the dispatched users set that the user creates in the initialization module 521.

(Direction Of Arrival DOA) carries out the multi-subscriber dispatching of MU-MIMO, has avoided the feedback of user to down channel in the process that the multi-user is matched based on user's the angle of arrival for above-mentioned method and device.(Frequency Division Duplex, FDD) (Time Division Duplex, TDD) pattern is suitable equally for pattern, time division duplex to Frequency Division Duplexing (FDD) for this method.Owing to do not need to calculate the capacity of dispatched users set, it is lower based on the computation complexity of the multi-user dispatching method of dispatched users aggregate capacity than prior art based on the computation complexity of the multi-user dispatching method of DOA that the embodiment of the invention provided, can save a large amount of computational resources in actual applications, particularly evident when this advantage number of users and antenna for base station in the MU-MIMO system is more.

Proposing the angle threshold value according to formula (2-6) among this method embodiment is in order to be easy to set forth technical scheme of the present invention, can not to think the qualification to employed angle threshold value in the technical solution of the present invention.For example an angle threshold value in the technical scheme that the embodiment of the invention provided can be expanded to two angle threshold values.In like manner, formula (2-7) also can be described with other form.And the criterion of selecting main user in the formula (2-5) also can be not limited to select the user of up channel impulse response maximum be main user, also can use other index that can characterize channel quality as the criterion of selecting main user, as to select the best user of channel signal to noise ratio be main user.It is just thinkable that these variants of the embodiment of the invention all are that one of ordinary skill in the art thought according to the present invention is easy to, so long as the technical scheme of carrying out multi-subscriber dispatching based on user's DOA should be considered to be encompassed within protection scope of the present invention.

In sum, more than be preferred embodiment of the present invention only, be not to be used to limit protection scope of the present invention.Within the spirit and principles in the present invention all, any modification of being done, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (10)

1, a kind of method of multi-subscriber dispatching is characterized in that, comprises

Obtain the angle of arrival DOA information of the dispatched users that remains in the sub-district;

DOA information based on the dispatched users that remains in the described sub-district is chosen the user.

2, method according to claim 1 is characterized in that, the described DOA information of obtaining the dispatched users that remains in the sub-district comprises:

Measure that each treats the up channel impulse response of dispatched users in the described sub-district;

Calculate according to described up channel impulse response that each treats the space correlation battle array of dispatched users in the described sub-district;

Calculate that each treats the array response vector of the angle that dispatched users need be searched in the described sub-district;

According to described space correlation battle array and described array response vector to each treats that dispatched users searches for to obtain DOA information in the described sub-district.

3, method according to claim 1 is characterized in that, describedly chooses the user based on the DOA information of the dispatched users that remains in the sub-district and comprises:

The set of initialization dispatched users;

Based on the DOA Information Selection user of the dispatched users that remains in the sub-district in the dispatched users set.

4, method according to claim 3 is characterized in that, described initialization dispatched users set comprises:

The set of establishment dispatched users;

Select in the described sub-district in the dispatched users that remains the best user of down channel quality as main user it is selected into described dispatched users set.

5, method according to claim 4 is characterized in that, the best user of described selection down channel quality comprises as main user:

Receive in the sub-district the quality information of the down channel that feeds back of the dispatched users that remains;

Select the best user of down channel quality as main user according to described quality information.

6, method according to claim 4 is characterized in that, if in tdd systems, in the described selection sub-district in the dispatched users that remains the best user of down channel quality comprise as main user:

Select in the sub-district in the dispatched users that remains the user of the mould value maximum of up channel impulse response as main user.

7, method according to claim 3 is characterized in that, describedly comprises based on the user in the DOA Information Selection dispatched users set for the treatment of all users in the dispatching cell:

A, the angle threshold value is set, the set of the dispatched users after the initialization is gathered as current scheduling user;

B, constitute current residual user set after the dispatched users that remains in the described sub-district removed user in the current scheduling user set, DOA information and described angle threshold value based on the dispatched users that remains in the sub-district are chosen a user in current residual user set, if do not choose the user, stop scheduling flow; If choose a user, the user who chooses is added the current scheduling user set;

C, judge that whether the number of users in the current scheduling user set reaches the described maximum number of user for the treatment of that dispatching cell can hold, if reach, stops scheduling flow; If do not reach, return step b.

8, method according to claim 7 is characterized in that, described DOA information and described angle threshold value based on the dispatched users that remains in the sub-district chosen a user and comprised in described current residual user's set:

Calculate the angle of arrival poor of user in the angle of arrival of user in the set of described remaining users and the set of described dispatched users;

If have a user in the described remaining users set, make in all users of described remaining users set, the difference maximum of user's the angle of arrival in described user's the angle of arrival and the set of described dispatched users, and the difference of the angle of arrival of described maximum is greater than described angle thresholding, with described user as a described user who chooses.

9, a kind of device that is used for multi-subscriber dispatching is characterized in that, comprising:

The DOA acquiring unit is used to obtain the DOA information of the dispatched users that remains in the sub-district;

User pairing unit is used for choosing the user based on the DOA information of the dispatched users that remains in the sub-district.

10, device according to claim 9 is characterized in that, described user pairing unit comprises:

Initialization module is used for the set of initialization dispatched users;

The user chooses module, and the DOA information of the dispatched users that remains in the sub-district that is used for being obtained based on described DOA information acquisition unit is selected in the dispatched users set that the user creates in the described initialization module.

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