CN102487549B - Method and device for scheduling user equipment in MIMO (multiple-input multiple-output) wireless communication system - Google Patents

Abstract

The invention relates to a method and a device for scheduling user equipment, wherein the method comprises the following steps: enabling a scheduling device to firstly get channel information of the multiple user equipment, and then selecting K paired user equipment in a two-and-two paring way according to the got channel information of the multiple user equipment so as to enable total system capacity and mutual orthogonality of the K paired user equipment to meet preset conditions. The method disclosed by the invention has the following advantages: comprehensively considering the orthogonality and the system capacity of channels, reducing multi-user interference by utilizing multiuser diversity, being simple to implement and having lower complexity and better fairness.

Description

Method and apparatus for user equipment scheduling in a MIMO wireless communication system

Technical Field

The present invention relates to the field of MIMO wireless communication, and in particular, to a method and apparatus for scheduling a user equipment in a MIMO wireless communication system.

Background

MIMO systems can increase wireless channel capacity and significantly improve communication quality. However, in actual uplink system transmission, due to the limitation of conditions such as power and volume, a user terminal cannot adopt a multi-antenna configuration, and is generally equipped with a single antenna. In order to implement MIMO communication, a technique of implementing space division multiplexing by scheduling two single-antenna user equipments to form virtual MIMO (V-MIMO) is proposed. The base station selects two or more users to pair according to a certain scheduling criterion to form multi-user MIMO transmission, and the scheduling criterion can influence the performance of the whole system.

The existing scheduling criteria are the following:

1. random Pairing (RP): i.e. the base station randomly selects the second user to pair.

2. Orthogonal Pairing (OP): namely, the base station selects the user with the largest channel orthogonality with the first user for pairing. The composite channel is H ═ H₁H₂]Wherein H is₁And H₂Channels representing user equipment 1 and user equipment 2, respectively, the base station is based on:

$D=\frac{|f_{11}+f_{22}|-|f_{12}+f_{21}|}{\mathrm{tr}\left(F\right)},$

and selecting the user equipment with the maximum D value as the paired user equipment, wherein,

3. determinant Pairing (DP): this scheme is similar to Orthogonal Pairing (OP), the only difference being that the numerator part of the formula for criterion D is different, namely:

$D=\frac{\det \left(F\right)}{\mathrm{tr}\left(F\right)}$

for the three schemes, the Random Pairing (RP) scheme is low in complexity, relatively simple and easy to implement, but cannot achieve the maximum cell throughput because channel information is not utilized, and may generate severe interference and may not effectively utilize resources; the implementation complexity of the Orthogonal Pairing (OP) scheme and the Determinant Pairing (DP) scheme is relatively low; the two schemes select the user equipment with the maximum orthogonal channel to pair so as to reduce the interference between two users; although the orthogonality of the channels is taken into account, the signal-to-noise ratio of each user is not taken into account.

Therefore, how to schedule users, reduce pairing interference and increase the capacity of the uplink system is a current problem.

Disclosure of Invention

The invention aims to provide a method and equipment for scheduling user equipment in a MIMO wireless communication system.

According to an aspect of the present invention, there is provided a method for scheduling a user equipment in a MIMO-based wireless communication system, wherein the method comprises the steps of:

a, acquiring channel information of a plurality of user equipment;

b, selecting K paired user equipment according to the acquired channel information of the user equipment, so that the total system capacity and mutual orthogonality of the K paired user equipment meet the preset conditions.

According to another aspect of the present invention, there is also provided an apparatus for user equipment scheduling in a MIMO-based wireless communication system, wherein the apparatus comprises:

acquiring means for acquiring channel information of a plurality of user equipments;

and the scheduling device is used for selecting the K paired user equipment according to the acquired channel information of the plurality of user equipment, so that the total system capacity and mutual orthogonality of the K paired user equipment meet the preset conditions.

Compared with the prior art, the invention has the following advantages: the orthogonality and the system capacity of the channel are comprehensively considered, the multi-user interference is reduced by utilizing the multi-user diversity, the implementation is simple, and the method has lower complexity and better fairness.

Drawings

Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments made with reference to the following drawings:

FIG. 1 is a system topology diagram for user equipment scheduling according to the present invention;

FIG. 2 is a flow chart of a method for user equipment scheduling in accordance with an aspect of the present invention;

FIG. 3 is a flow chart of a method for user equipment scheduling in accordance with another aspect of the present invention;

FIG. 4 is a diagram of an apparatus for scheduling user equipment in accordance with an aspect of the present invention;

FIG. 5 is a schematic diagram of the performance comparison of the present invention with a random pairing, orthogonal pairing, and determinant pairing scheme;

the same or similar reference numbers in the drawings identify the same or similar elements.

Detailed Description

The present invention is described in further detail below with reference to the attached drawing figures.

Fig. 1 shows a system topology for user equipment scheduling according to the present invention. User device 11, user device 12,... user device 1K may be any electronic device capable of communicating wirelessly with scheduling device 2, including but not limited to: cell phones, PDAs, etc. The scheduling device 2 may be an electronic device capable of scheduling user devices, including but not limited to: 1) base stations, e.g., BS, e-Node B; 2) a network controller, etc. The user equipment 11, the user equipment 12, the.

Preferably, each user equipment, for example, user equipment 11, user equipment 12, 1K, comprises only one antenna, so that a virtual MIMO (V-MIMO) based wireless communication system is formed between each user equipment and scheduling apparatus 2.

Fig. 2 shows a flow chart of a method for user equipment scheduling in accordance with an aspect of the invention.

Specifically, in step S01, the scheduling apparatus 2 acquires the channel information of the plurality of user equipments. For example, the scheduling device 2 acquires channel information of the user device 11, the user device 12.

As a preferable mode, the mode of the scheduling device 2 acquiring the channel information of each user device may be feedback from each user device. For example, the user equipment 11 and the user equipment 12, say₁The user equipment 12 estimates the channel information between itself and the scheduling equipment 2 to be H₂,... times.user equipment 1K estimates that channel information between itself and scheduling device 2 is H_KThen, the user equipment 11, 12,... the user equipment 1K will each estimate channel information, for example: h₁、H₂、......H_KAnd feeding back to the scheduling device 2. Since the techniques for estimating the channel information according to the received information are known to those skilled in the art, they will not be described in detail herein.

Furthermore, those skilled in the art should understand that the manner of acquiring the channel information of each user equipment by the scheduling device 2 is not limited to the above, for example, the scheduling device 2 may acquire the channel information of each user equipment from a base station communicating with each user equipment, and the like.

Next, in step S02, the scheduling device 2 selects K paired user devices according to the acquired channel information of the plurality of user devices, so that the total system capacity and mutual orthogonality of the K paired user devices satisfy a predetermined condition. For example, the scheduling device 2 obtains channel information H of the user device 11, the user device 12₁、H₂、......H_KSelecting pairwise pairing of K paired user devices such that the total of the K paired user devicesThe system capacity and mutual orthogonality satisfy predetermined conditions.

Subsequently, the scheduling device 2 or the base station allocates the same time-frequency resource for the paired user equipment to perform data transmission. This process is well known to those skilled in the art and will not be described in detail herein.

Fig. 3 shows a flow chart of a method for user equipment scheduling in accordance with another aspect of the invention.

Specifically, in step S01', the scheduling apparatus 2 acquires the channel information of the plurality of user equipments. For example, the scheduling device 2 obtains the channel matrix H of the user equipment 11 and the user equipment 12 from a base station (not shown)₁、H₂、......H_K。

Those skilled in the art should understand that the manner for the scheduling device 2 to acquire the channel information of each user equipment is not limited to the above, for example, the manner for the scheduling device 2 to acquire may also be channel information fed back from each user equipment.

Next, in step S02', the scheduling device 2 selects K paired user devices according to the acquired channel information of the plurality of user devices, so that the total system capacity and mutual orthogonality of the K paired user devices satisfy the judgment criterion.

Wherein the selection of the K paired user devices satisfies the following criteria:

{ user 1, user 2., user K } ═ argmax (d),

wherein,

and, H ═ H₁H₂…H_K]Wherein H is_iA channel matrix representing the ith user equipment. That is, the scheduling device 2 pairs K user devices two by two to form a pair combination, and then calculates the pair combination based on each pair combination according to the above formulaCorresponding D is obtained, for example, the scheduling device 2 calculates D based on pairwise pairing combination of { { user equipment 11, user equipment 12}, { user equipment 13, user equipment 14}, }₁(ii) a The scheduling device 2 calculates D based on pairwise pairing combination of { { user equipment 11, user equipment 13}, { user equipment 12, user equipment 14}, { user equipment 1K-1, user equipment 1K } }₂..., then, device 2 is dispatched from D₁、D₂... selecting the pairwise pairing mode of the user equipment corresponding to the largest user.

And if k is 2, the selection of two paired user equipments satisfies the following judgment criteria:

wherein,(i, j ≠ K ≠ j) 1, 2, and H_i、H_jRespectively representing the channel matrixes of the ith user equipment and the jth user equipment.

As a preferred mode, the scheduling device 2 may select a first user according to a certain policy, such as polling, proportional fair, and the like, and then select another paired user device according to the above determination criteria. For example, the scheduling device 2 selects a user device, for example, the user device 11, according to the proportional fair policy, and then the scheduling device 2 selects a user device that can be paired with the user device 11, for example, the user device 13, from the user devices 12, 1K according to the judgment criterion adopted for selecting two paired user devices; then, the scheduling device 2 selects a user equipment, for example, the user equipment 12, according to the proportional fair policy, and the scheduling device 2 selects a user equipment that can be paired with the user equipment 12 from the user equipment 14, the.

Then, based on the pairing mode of the user equipment 11 and the user equipment 12 obtained by the scheduling equipment 2, the scheduling equipment 2 or the base station allocates the same time-frequency resource to the paired user equipment for data transmission. This process is well known to those skilled in the art and will not be described in detail herein.

Fig. 4 shows a system diagram for user equipment scheduling according to an aspect of the present invention. The system comprises: user equipment 11, user equipment 12, 1K, and scheduling device 2. Wherein, the scheduling device 2 includes: an acquisition device 21 and a scheduling device 22.

Specifically, the obtaining device 21 obtains channel information of a plurality of user equipments. For example, the obtaining means 21 obtains channel information of the user equipment 11, the user equipment 12.

As a preferable mode, the mode of acquiring the channel information of each user equipment by the acquiring means 21 may be feedback from each user equipment. For example, the user equipment 11 and the user equipment 12, say₁The user equipment 12 estimates the channel information between itself and the scheduling equipment 2 to be H₂,... times.user equipment 1K estimates that channel information between itself and scheduling device 2 is H_KThen, the user equipment 11, 12,... the user equipment 1K will each estimate channel information, for example: h₁、H₂、......H_KAnd feeding back to the scheduling device 2. Since the techniques for estimating the channel information according to the received information are known to those skilled in the art, they will not be described in detail herein.

Furthermore, those skilled in the art should understand that the manner of acquiring the channel information of each user equipment by the acquiring means 21 is not limited to the above, for example, the acquiring means 21 may acquire the channel information of each user equipment from a base station communicating with each user equipment, and the like.

Next, the scheduling device 22 selects K paired user equipments according to the acquired channel information of the plurality of user equipments, so that the total system capacity and mutual orthogonality of the K paired user equipments satisfy a predetermined condition. For example, the scheduling device 22 obtains the channel information H of the user equipment 11, 12₁、H₂、......H_KAnd selecting a pairwise pairing mode of the K paired user equipment so that the total system capacity and mutual orthogonality of the K paired user equipment meet a preset condition.

Then, the scheduling device 2 or the base station allocates the same time-frequency resource to the selected user equipment for data transmission. This process is well known to those skilled in the art and will not be described in detail herein.

A procedure for user equipment scheduling according to another aspect of the system will be described in detail below based on the system shown in fig. 4.

Specifically, the obtaining device 21 obtains channel information of a plurality of user equipments. For example, the obtaining device 21 obtains the channel matrix H of the user equipment 11 and the user equipment 12 from a base station (not shown)₁、H₂、......H_K。

Those skilled in the art should understand that the manner of acquiring the channel information of each user equipment by the acquiring device 21 is not limited to the above, for example, the acquiring device 21 may also acquire the channel information fed back from each user equipment.

Next, the scheduling device 22 selects K paired user equipments according to the acquired channel information of the multiple user equipments, so that the total system capacity and mutual orthogonality of the K paired user equipments satisfy the judgment criterion.

Wherein the selection of the K paired user devices satisfies the following criteria:

{ user 1, user 2., user K } ═ argmax (D),

wherein,

and, H ═ H₁H₂…H_K]Wherein H is_iA channel matrix representing the ith user equipment. That is, the scheduling apparatus 22 pairs K user equipments two by two to form a pair combination, and then calculates D according to the above formula based on each pair combination, for example, the scheduling apparatus 22 calculates D based on the pair combination of { { user equipment 11, user equipment 12}, { user equipment 13, user equipment 14}, { user equipment 1K-1, user equipment 1K } }₁(ii) a The scheduling apparatus 22 calculates D based on pairwise pairing combination of { { user equipment 11, user equipment 13}, { user equipment 12, user equipment 14}, { user equipment 1K-1, user equipment 1K } }₂..., then, device 2 is dispatched from D₁、D₂... selecting the pairwise pairing mode of the user equipment corresponding to the largest user.

If k is 2, the selection of two paired user devices satisfies the following criteria:

wherein,(i, j ≠ K ≠ j) 1, 2, and H_i、H_jRespectively representing the channel matrixes of the ith user equipment and the jth user equipment.

As a preferred mode, the scheduling device 22 may select a first user according to a certain policy, such as polling, proportional fair, etc., and then select another paired user equipment according to the above-mentioned determination criteria. For example, the scheduling device 22 selects a user equipment, for example, the user equipment 11, according to the proportional fair policy, and then the scheduling device 2 selects a user equipment that can be paired with the user equipment 11, for example, the user equipment 13, from the user equipment 12, ·..... the user equipment 1K according to the judgment criterion adopted for selecting two paired user equipments; then, the scheduling device 2 selects a user equipment, for example, the user equipment 12, according to the proportional fair policy, and the scheduling apparatus 22 selects a user equipment that can be paired with the user equipment 12 from the user equipment 14, the.

Then, based on the pairing mode of the user equipment 11 and the user equipment 12, the. This process is well known to those skilled in the art and will not be described in detail herein.

The advantages of the present invention will be described in the following experimental simulation results.

The simulation conditions include: the transmission power of each user equipment is 10mW, the noise power is 1mW, each user equipment adopts a Minimum Mean Square Error (MMSE) receiver, the number of the scheduled user equipment is 20, if the two finally scheduled user equipment are selected from the 20 user equipment, the simulation result is shown in figure 5, and the user equipment pairing scheme can be seen from the figure, so that the system capacity can be obviously improved compared with the conventional random pairing scheme, orthogonal pairing scheme and determinant pairing scheme.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned. Furthermore, it is obvious that the word "comprising" does not exclude other elements or steps, and the singular does not exclude the plural. A plurality of units or means recited in the system claims may also be implemented by one unit or means in software or hardware. The terms first, second, etc. are used to denote names, but not any particular order.

Claims (7)

1. A method for user equipment scheduling in a MIMO based wireless communication system, wherein the method comprises the steps of:

a, acquiring channel information of a plurality of user equipment;

b, according to the acquired channel information of the plurality of user equipment, selecting K paired user equipment so that the total system capacity and mutual orthogonality of the K paired user equipment meet a predetermined condition, wherein the predetermined condition comprises:

the selection of the K paired user devices satisfies the following criteria:

{ user 1, user 2., user K } ═ argmax (D),

wherein,

and, H ═ H₁H₂...H_K]Wherein H is_iRepresenting the channel matrix of user equipment i.

2. The method of claim 1, wherein K is 2, the predetermined condition comprising:

the selection of two paired user devices satisfies the following criteria:

wherein,and H_i、H_jRespectively representing the channel matrices of user equipment i and user equipment j.

3. The method of claim 1 or 2, wherein the wireless communication system comprises a V-MIMO based wireless communication system.

4. An apparatus for user equipment scheduling in a MIMO based wireless communication system, wherein the apparatus comprises:

acquiring means for acquiring channel information of a plurality of user equipments;

a scheduling device, configured to select K paired user equipments according to the acquired channel information of the multiple user equipments, so that a total system capacity and mutual orthogonality of the K paired user equipments satisfy a predetermined condition, where the predetermined condition includes:

the selection of the K paired user devices satisfies the following criteria:

{ user 1, user 2., user K } ═ argmax (D),

wherein,

and, H ═ H₁H₂...H_K]Wherein H is_iRepresenting the channel matrix of user equipment i.

5. The apparatus of claim 4, wherein K is 2, the predetermined condition comprising:

the selection of the two paired user devices satisfies the following criteria:

wherein,and H_i、H_jRespectively representing the channel matrices of user equipment i and user equipment j.

6. The apparatus of claim 4 or 5, wherein the wireless communication system comprises a V-MIMO based wireless communication system.

7. A MIMO based system comprising the apparatus of any one of claims 4 to 6 and a plurality of user equipments.