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

Abstract

The present invention relates to a method and equipment for user equipment scheduling. Wherein, the scheduling device first obtains the channel information of multiple user equipments, and then selects a pairwise pairing mode of K paired user equipments according to the obtained channel information of multiple user equipments, so that the total number of K paired user equipments The system capacity and mutual orthogonality satisfy predetermined conditions. The invention has the following advantages: the orthogonality of the channel and the system capacity are considered comprehensively, the multi-user interference is reduced by using the multi-user diversity, the implementation is simple, the complexity is low and the fairness is good.

Description

Method and device for user equipment scheduling in MIMO wireless communication system

technical field

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

Background technique

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

The existing scheduling criteria are as follows:

1. Random pairing (RP): the base station randomly selects the second user for pairing.

2. Orthogonal pairing (OP): that is, the base station selects the user whose channel is the most orthogonal to the first user for pairing. The composite channel is H=[H ₁ H ₂ ], where H ₁ and H ₂ represent the channels of UE 1 and UE 2 respectively, and the base station is based on:

$\mathrm{<span\; class="notranslate">\; D.</span>}<span\; class="notranslate">\; =</span>\frac{<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 11</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; twenty\; two</span>}}<span\; class="notranslate">\; |</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; 12</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; twenty\; one</span>}}<span\; class="notranslate">\; |</span>}{\mathrm{<span\; class="notranslate">\; tr</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; ,</span>$

Select the user equipment with the largest D value as the paired user equipment, where,

3. Determinant pairing (DP): This scheme is similar to orthogonal pairing (OP), the only difference is that the molecular part of the criterion D expression is different, namely:

$\mathrm{<span\; class="notranslate">\; D.</span>}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; det</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; tr</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; )</span>}$

Among the above three schemes, the Random Pairing (RP) scheme has low complexity, is relatively simple, and is easy to implement, but because it does not use channel information, this scheme cannot achieve the maximum throughput of the cell, and this pairing scheme may cause serious problems. The interference and the inability to effectively use resources; while the implementation complexity of the Orthogonal Pairing (OP) scheme and the Determinant Pairing (DP) scheme is relatively low; both schemes select the user equipment with the maximum orthogonalization of the channel for pairing , to reduce the interference between two users; although the orthogonality of the channel is considered, the signal-to-noise ratio of each user is not considered.

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

Contents of the invention

The object of the present invention is to provide a method and device for user equipment scheduling in a MIMO wireless communication system.

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

a acquiring channel information of multiple user equipments;

b. Select K paired user equipments according to the acquired channel information of multiple user equipments, so that the total system capacity and mutual orthogonality of the K paired user equipments meet a predetermined condition.

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

an obtaining device, configured to obtain channel information of multiple user equipments;

The scheduling device is configured to select 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 meet predetermined conditions.

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

Description of drawings

Other characteristics, objects and advantages of the present invention will become more apparent by reading 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 flowchart of a method for user equipment scheduling according to one aspect of the present invention;

FIG. 3 is a flowchart of a method for user equipment scheduling according to another aspect of the present invention;

FIG. 4 is a schematic diagram of a device for user equipment scheduling according to one aspect of the present invention;

Fig. 5 is a schematic diagram of performance comparison between the present invention and random matching, orthogonal matching, and determinant matching schemes;

The same or similar reference numerals in the drawings represent the same or similar components.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings.

Fig. 1 shows a system topology diagram for user equipment scheduling in the present invention. User equipment 11 , user equipment 12 , . . . user equipment 1K may be any electronic equipment that can communicate with dispatching equipment 2 in a wireless manner, including but not limited to: mobile phones, PDAs, etc. The scheduling device 2 may be an electronic device capable of scheduling user equipment, including but not limited to: 1) a base station, such as BS, e-Node B; 2) a network controller, etc. Each of user equipment 11, user equipment 12, ... user equipment 1K includes at least one antenna, and scheduling device 2 includes multiple antennas. Therefore, user equipment 11, user equipment 12, ... user The device 1K and the scheduling device 2 constitute a wireless communication system based on MIMO technology (multi user-multiple input multiple output techniques).

As a preferred manner, each user equipment, for example, user equipment 11, user equipment 12, ... user equipment 1K, each includes only one antenna, thus, each user equipment and the scheduling device 2 form a A wireless communication system based on virtual MIMO (V-MIMO).

Fig. 2 shows a flowchart of a method for user equipment scheduling in one aspect of the present invention.

Specifically, in step S01, the scheduling device 2 acquires channel information of multiple user equipments. For example, scheduling device 2 acquires channel information of user equipment 11, user equipment 12, ... user equipment 1K.

As a preferred manner, the manner in which the scheduling device 2 obtains the channel information of each user equipment may be feedback from each user equipment. For example, user equipment 11, user equipment 12, ... user equipment 1K each estimates the channel information between itself and the scheduling device 2 according to the received transmission signal. The channel information between 2 is H ₁ , the user equipment 12 estimates the channel information between itself and the scheduling device 2 as H ₂ , ... the user equipment 1K estimates the channel information between itself and the scheduling device 2 is H _K , then, user equipment 11, user equipment 12, ... user equipment 1K will feed back their estimated channel information, for example: H ₁ , H ₂ , ... H _K , to Schedule device 2. Since those skilled in the art already know the technology of how the user equipment estimates channel information according to the received information, it will not be described in detail here.

In addition, those skilled in the art should understand that the manner in which the scheduling device 2 obtains the channel information of each user equipment is not limited to the above, for example, the scheduling device 2 may obtain the channel information of each user equipment from a base station communicating with each user equipment.

Next, in step S02, the scheduling device 2 selects K paired user equipments according to the acquired channel information of multiple user equipments, so that the total system capacity and mutual orthogonality of the K paired user equipments meet predetermined conditions. For example, the scheduling device 2 selects K paired user equipments according to the obtained channel information H ₁ , H ₂ , ... H _K of the user equipment 11, user equipment 12, ... user equipment 1K The pairwise pairing manner of the K paired user equipments makes the total system capacity and mutual orthogonality of the K paired user equipments satisfy a predetermined condition.

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 known to those skilled in the art, so it will not be described in detail here.

Fig. 3 shows a flowchart of a method for user equipment scheduling according to another aspect of the present invention.

Specifically, in step S01', the scheduling device 2 acquires channel information of multiple user equipments. For example, the scheduling device 2 obtains the channel matrices H ₁ , H 2 , ... H _K of the user equipment 11 , user equipment ₁₂ , ... user equipment 1K from a base station (not shown in the figure).

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

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

Among them, the selection of K paired user equipments meets the following judgment criteria:

{User1, User2, ..., UserK} = argmax(D),

in,

And, H=[H ₁ H ₂ . . . H _K ], where H _i represents the channel matrix of the i-th user equipment. That is, the scheduling device 2 pairs K user equipments in pairs to form a pairing combination, and then calculates the corresponding D according to the above formula based on each pairing combination. For example, the scheduling device 2 is based on {{user equipment 11, user equipment 12 }, {user equipment 13 _, user equipment 14}, ...... Equipment 11, user equipment 13}, {user equipment 12, user equipment 14}, ...{user equipment 1K-1, user equipment 1K}} are paired and combined to calculate D ₂ ... ..., and then, the scheduling device 2 selects the pairwise pairing mode of the user equipment corresponding to the largest one from D ₁ , D ₂ . . . .

And if k=2, the selection of two paired user equipments meets the following criteria:

in, (i, j=1, 2,...K; i≠j), and H _i , H _j represent the channel matrix of the i-th user equipment and the j-th user equipment respectively.

As a preferred manner, the scheduling device 2 may first select the first user according to a certain strategy, such as round robin, proportional fairness, etc., and then select another paired user equipment according to the above judgment criteria. For example, the scheduling device 2 first selects a user equipment according to the proportional fairness strategy, for example, the user equipment 11, and then the scheduling device 2 selects two paired user equipment according to the above-mentioned judgment criteria, among the user equipment 12, ... Select the user equipment that can be paired with the user equipment 11 from the user equipment 1K, for example, select the user equipment 13; then, the scheduling device 2 selects a user equipment according to the proportional fairness strategy, for example, the user equipment 12, and the scheduling device 2 again According to the judgment criterion adopted for selecting two paired user equipments, select the user equipment that can be paired with the user equipment 12 among the user equipment 14, ... the user equipment 1K, ... and schedule the equipment in this way 2. The user equipment 11, user equipment 12, . . . user equipment 1K can be paired in pairs.

Subsequently, based on the two-two pairing mode of user equipment 11, user equipment 12, ... user equipment 1K obtained by scheduling device 2, scheduling device 2 or the base station allocates the same time-frequency resource for the paired user equipment to perform data processing. transmission. This process is known to those skilled in the art, so it will not be described in detail here.

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

Specifically, the acquiring module 21 acquires channel information of multiple user equipments. For example, the obtaining means 21 obtains channel information of user equipment 11, user equipment 12, ... user equipment 1K.

As a preferred manner, the acquiring means 21 acquires channel information of each user equipment may be feedback from each user equipment. For example, user equipment 11, user equipment 12, ... user equipment 1K each estimates the channel information between itself and the scheduling device 2 according to the received transmission signal. The channel information between 2 is H ₁ , the user equipment 12 estimates the channel information between itself and the scheduling device 2 as H ₂ , ... the user equipment 1K estimates the channel information between itself and the scheduling device 2 is H _K , then, user equipment 11, user equipment 12, ... user equipment 1K will feed back their estimated channel information, for example: H ₁ , H ₂ , ... H _K , to Schedule device 2. Since those skilled in the art already know the technology of how the user equipment estimates channel information according to the received information, it will not be described in detail here.

In addition, those skilled in the art should understand that the manner in which the acquiring means 21 acquires the channel information of each user equipment 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.

Next, the scheduling means 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 meet predetermined conditions. For example, the scheduling device 22 selects K paired user equipments according to the obtained channel information H ₁ , H ₂ , ... H _K of the user equipment 11, user equipment 12, ... user equipment 1K The pairwise pairing manner of the K paired user equipments makes the total system capacity and mutual orthogonality of the K paired user equipments satisfy a predetermined condition.

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

Based on the system shown in FIG. 4 , the process for user equipment scheduling in another aspect of the system will be described in detail below.

Specifically, the acquiring module 21 acquires channel information of multiple user equipments. For example, the acquiring means 21 acquires channel matrices H ₁ , H ₂ , ... H _K of user equipment 11 , user equipment 12 , ... user equipment 1K from a base station (not shown in the figure).

Those skilled in the art should understand that the manner in which the acquiring means 21 acquires the channel information of each user equipment is not limited to the above, for example, the acquiring means 21 may also acquire 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 meet the judgment criterion.

Among them, the selection of K paired user equipments meets the following judgment criteria:

{User1, User2, ..., UserK} = arg max(D),

in,

And, H=[H ₁ H ₂ . . . H _K ], where H _i represents the channel matrix of the i-th user equipment. That is, the scheduling device 22 pairs K user equipments in pairs to form a pairing combination, and then calculates the corresponding D based on each pairing combination according to the above formula. For example, the scheduling device 22 is based on {{user equipment 11, user equipment 12 }, {user equipment 13, user equipment 14}, ...... {user equipment 1K-1, user equipment 1K}} paired combination, calculate D ₁ ; scheduling device 22 is based on {{user Equipment 11, user equipment 13}, {user equipment 12, user equipment 14}, ...{user equipment 1K-1, user equipment 1K}} are paired and combined to calculate D ₂ ... ..., and then, the scheduling device 2 selects the pairwise pairing mode of the user equipment corresponding to the largest one from D ₁ , D ₂ . . . .

If k=2, the selection of two paired user equipments meets the following criteria:

in, (i, j=1, 2,...K; i≠j), and H _i , H _j represent the channel matrix of the i-th user equipment and the j-th user equipment respectively.

As a preferred manner, the scheduling device 22 may first select the first user according to a certain strategy, such as round robin, proportional fairness, etc., and then select another paired user equipment according to the above judgment criteria. For example, the scheduling device 22 first selects a user equipment according to the proportional fairness strategy, for example, the user equipment 11, and then the scheduling device 2 selects two paired user equipment according to the above-mentioned judging criteria used to select the user equipment 12, ... Select the user equipment that can be paired with the user equipment 11 from the user equipment 1K, for example, select the user equipment 13; then, the scheduling device 2 selects a user equipment according to the proportional fairness strategy, for example, the user equipment 12, and the scheduling device 22 again According to the judgment criterion adopted for selecting two paired user equipments, select the user equipment that can be paired with the user equipment 12 from the user equipment 14, ... the user equipment 1K, ... so that the scheduling device 22 can obtain user equipment 11 , user equipment 12 , . . . user equipment 1K in pairs.

Subsequently, based on the pairwise pairing mode of user equipment 11, user equipment 12, ... user equipment 1K obtained by the scheduling device 22, the scheduling device 2 or the base station allocates the same time-frequency resource for the paired user equipment for data processing. transmission. This process is known to those skilled in the art, so it will not be described in detail here.

The superiority of the present invention will be illustrated with the experimental simulation results below.

The simulation conditions include: the transmit power of each user equipment is 10mW, the noise power is 1mW, each user equipment adopts a minimum mean square error (MMSE) receiver, and there are 20 scheduled user equipments. The user equipment is selected from 20 user equipment, and the simulation result is shown in Figure 5. From the figure, it can be seen that the user equipment pairing scheme of the present invention is different from the existing random pairing scheme, orthogonal pairing scheme, and determinant pairing scheme , can significantly increase the system capacity.

It will be apparent to those skilled in the art that the invention is not limited to the details of the above-described exemplary embodiments, but that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Accordingly, the embodiments should be regarded in all points of view as exemplary and not restrictive, the scope of the invention being defined by the appended claims rather than the foregoing description, and it is therefore intended that the scope of the invention be defined by the appended claims rather than by the foregoing description. All changes within the meaning and range of equivalents of the elements are embraced in the present invention. Any reference sign in a claim should not be construed as limiting the claim concerned. In addition, 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 devices stated in the system claims may also be realized by one unit or device through software or hardware. The words first, second, etc. are used to denote names and do not imply any particular order.

Claims (7)

1. A method for user equipment scheduling in a MIMO-based wireless communication system, wherein the method comprises the following steps: a acquiring channel information of multiple user equipments; b. Select K paired user equipments according to the acquired channel information of multiple user equipments, so that the total system capacity and mutual orthogonality of the K paired user equipments meet predetermined conditions, wherein the predetermined conditions include: The selection of the K paired user equipments satisfies the following criteria: {user1, user2,...,userK} = arg max(D), in, And, H=[H ₁ H ₂ . . . H _K ], where H _i represents the channel matrix of user equipment i. 2. The method according to claim 1, wherein K is 2, and the predetermined conditions include: The selection of the two paired user equipments satisfies the following judgment criteria: in, And H _i , H _j represent channel matrices of user equipment i and user equipment j respectively. 3. The method according to claim 1 or 2, wherein the wireless communication system comprises a V-MIMO based wireless communication system. 4. A device for performing user equipment scheduling in a MIMO-based wireless communication system, wherein the device comprises: an obtaining device, configured to obtain channel information of multiple user equipments; A scheduling device, configured to select K paired user equipments according to the acquired channel information of multiple user equipments, so that the total system capacity and mutual orthogonality of the K paired user equipments meet a predetermined condition, wherein the predetermined Conditions include: The selection of the K paired user equipments satisfies the following criteria: {user1, user2,...,userK} = arg max(D), in, And, H=[H ₁ H ₂ . . . H _K ], where H _i represents the channel matrix of user equipment i. 5. The device according to claim 4, wherein K is 2, and the predetermined conditions include: The selection of the two paired user equipments meets the following criteria: in, And H _i , H _j represent channel matrices of user equipment i and user equipment j respectively. 6. The device according to claim 4 or 5, wherein the wireless communication system comprises a V-MIMO based wireless communication system. 7. A system based on MIMO, wherein the system comprises the device according to any one of claims 4 to 6 and a plurality of user equipments.