WO2013189194A1

WO2013189194A1 - Channel information feedback method and user equipment

Info

Publication number: WO2013189194A1
Application number: PCT/CN2013/073032
Authority: WO
Inventors: 王宗杰; 徐飞; 邱玲
Original assignee: 华为技术有限公司
Priority date: 2012-06-21
Filing date: 2013-03-22
Publication date: 2013-12-27
Also published as: CN103516494B; CN103516494A

Abstract

The present invention provides a channel information feedback method and a user equipment. The method comprises: when a first user equipment is in a coordinated state, calculating a PCI, and calculating a first CQI when an interfering cell does not provide interference avoidance for the first user equipment; calculating a BCI, and calculating a second CQI when the interfering cell provides interference avoidance for the first user equipment; and feeding back one or a combination of the PCI, the BCI, the first CQI and the second CQI, and a difference between the second CQI and the first CQI to a base station where a serving cell is located. The present invention enables a user equipment at the edge of a cell to feed back channel information from the user equipment to a serving cell and channel information from the user equipment to an interfering cell to a base station, so that the base station performs coordination and scheduling on the cell under the base station, thereby improving the channel quality and communication rate of the user equipment at the edge of the cell.

Description

Channel information feedback method and user equipment The present application claims priority to the Chinese Patent Application filed on June 21, 2012, the Chinese Patent Application No. 201210208399.3, the invention entitled "Channel Information Feedback Method and User Equipment", the entire contents thereof This is incorporated herein by reference. TECHNICAL FIELD The present invention relates to communications technologies, and in particular, to a channel information feedback method and user equipment. BACKGROUND OF THE INVENTION The Universal Mobile Telecommunications System (UMTS) is currently the most widely used third-generation mobile communication technology. UMTS uses Wideband Code Division Multiple Access (WCDMA) as the air interface standard, and High Speed Downlink Packet Access (HSDPA) is an evolved version of the UMTS system. Multiple Input Multiple Output (MIMO), Hybrid Automatic Repeat Request (HQQ), Adaptive Modulation and Coding (hereinafter referred to as AMC) Technology such as high-order modulation greatly improves system performance: The theoretical limit of the transmission rate on the 5MHz carrier bandwidth can reach 28.8Mbps. However, in practical systems, users are affected by their location, current cell load, inter-user interference, and/or wireless channel fading. The actual reachability rate of users is much smaller than the theoretical upper bound of HSDPA rate. Especially for users at the edge of the cell, the existing HSDPA technology uses a scheme that is independently scheduled by each cell, and does not take into account the impact of the self-cell scheduling result on other cell edge users in the scheduling process, which makes the user At the edge of the cell, it is subject to neighbor cell interference compared with its own received signal, further limiting its actual rate.

Considering the situation when the user is at the edge of the cell, the neighboring cell with the largest interference to the user is the interfering cell. When the user is at the cell edge, the large-scale fading of the channel from the user to the serving cell can be compared with the large-scale fading of the channel to the interfering cell. In the prior art, since there is no feedback about the interference information of the neighboring cell, each cell performs independent Scheduling, did not take into account the tuning process The result may cause interference to the edge user, which causes the edge user to be compared with the received signal, so that the channel quality indicator (CQI) is reduced, and the communication rate is also Reduced. The present invention provides a channel information feedback method and a user equipment, so that the user equipment at the cell edge feeds back the channel information of the user equipment to the serving cell and the channel information of the user equipment to the interfering cell to the base station. The base station performs coordinated scheduling on the cells under the base station to improve channel quality and communication rate of user equipments at the cell edge.

An aspect of the present invention provides a channel information feedback method, including:

After the first user equipment is in the coordinated state, the first user equipment obtains the first channel matrix of the first user equipment to the serving cell by using channel estimation, and calculates the first user according to the first channel matrix. a precoding control indication of the device, and calculating, according to the precoding control indication, a first channel quality indicator when the interfering cell does not provide interference avoidance for the first user equipment;

The first user equipment obtains a second channel matrix of the first user equipment to the interfering cell by using channel estimation, and calculates a best pairing of the first user equipment for the interfering cell according to the second channel matrix. And indicating, according to the best pairing indication, a second channel quality indicator of the first user equipment when the interference d, the area provides interference avoidance for the first user equipment;

The first user equipment, the precoding control indication, the best pairing indication, the first channel quality indicator, and the second channel quality indicator, and the second channel quality indicator and the first One or a combination of the differences in channel quality indications is fed back to the base station where the serving cell is located.

Another aspect of the present invention provides a user equipment, where the user equipment is a first user equipment, and the user equipment includes: an obtaining module, a calculating module, and a feedback module;

And an obtaining module, configured to obtain, by using channel estimation, a first channel matrix of the first user equipment to a serving cell when the first user equipment is in a coordinated state; and obtain the first user equipment to interference by using channel estimation a second channel matrix of the cell;

a calculating module, configured to calculate, according to the first channel matrix obtained by the obtaining module, the first a precoding control indication of the user equipment, and calculating, according to the precoding control indication, a first channel quality indicator when the interfering cell does not provide interference avoidance for the first user equipment; and obtaining according to the obtaining module Calculating, by the second channel matrix, the best pairing indication of the first user equipment for the interfering cell, and calculating, according to the best pairing indication, the first when the interfering cell provides interference avoidance for the first user equipment a second channel quality indicator of the user equipment; a feedback module, configured to: the precoding control indication, the best pairing indication, the first channel quality indicator, and the second channel quality indicator, and the second One or a combination of the difference between the channel quality indicator and the first channel quality indicator is fed back to the base station where the serving cell is located.

The technical effect of the first aspect of the present invention is: when the first user equipment is in the coordinated state, the first user equipment obtains the first channel matrix of the first user equipment to the serving cell, calculates a precoding control indication, and when the interfering cell The first user equipment is not provided with the first channel quality indicator when the interference avoidance is performed; then, the first user equipment obtains the second channel matrix of the first user equipment to the interfering cell, and calculates the most a good pairing indication, and a second channel quality indicator of the first user equipment when the interfering cell provides interference avoidance for the first user equipment; the first user equipment, the precoding control indication, the best pairing indication, the first channel quality indicator, and The second channel quality indicator, and one or a combination of the difference between the second channel quality indicator and the first channel quality indicator, is fed back to the base station where the serving cell is located; thereby, the user equipment at the cell edge can implement the user equipment to the serving cell. Channel information, and the channel of the user equipment to the interfering cell Information together to the base station, the base station for cooperative scheduling of the cell under the base station, in turn, can improve the channel quality and the communication rate of the user equipment at a cell edge.

The technical effect of another aspect of the present invention is: when the first user equipment is in the coordinated state, after the obtaining module obtains the first channel matrix of the first user equipment to the serving cell, the calculating module calculates a precoding control indication, and when the interference The cell does not provide the first channel quality indicator for the first user equipment when the interference is avoided. Then, the obtaining module obtains the second channel matrix of the first user equipment to the interfering cell, and the calculating module calculates the most a good pairing indication, and a second channel quality indicator of the first user equipment when the interfering cell provides interference avoidance for the first user equipment; the feedback module sets the precoding control indication, the best pairing indication, the first channel quality indicator, and the second The channel quality indicator, and one or a combination of the difference between the second channel quality indicator and the first channel quality indicator is fed back to the base station where the serving cell is located; The user equipment at the edge of the cell feeds back the channel information of the user equipment to the serving cell and the channel information of the user equipment to the interfering cell to the base station, so that the base station performs coordinated scheduling on the cell under the base station, thereby improving the Channel quality and communication rate of user equipment at the edge of the cell. BRIEF DESCRIPTION OF THE DRAWINGS In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, a brief description of the drawings used in the embodiments or the prior art description will be briefly described below. The drawings are some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any inventive labor.

1 is a flowchart of an embodiment of a channel information feedback method according to the present invention;

2 is a flowchart of an embodiment of a user scheduling method according to the present invention;

3 is a flowchart of another embodiment of a user scheduling method according to the present invention;

FIG. 4 is a schematic structural diagram of an embodiment of a user equipment according to the present invention. The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. The embodiments are a part of the embodiments of the invention, and not all of the embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

1 is a flowchart of an embodiment of a channel information feedback method according to the present invention. As shown in FIG. 1, the channel information feedback method may include:

Step 101: After the first user equipment is in the coordinated state, the first user equipment obtains the first channel matrix of the serving cell of the first user equipment by using the channel estimation, and calculates the foregoing according to the first channel matrix. a precoding control indicator (hereinafter referred to as PCI) of the first user equipment, and calculating, according to the foregoing PCI, a first channel quality indicator when the interfering cell of the first user equipment does not provide interference avoidance for the first user equipment ( Channel Quality Indicator; hereinafter referred to as: CQI).

Specifically, the first user equipment in the coordinated state may be: when the first user equipment is up When the difference between the signal strength of the serving cell and the signal strength of the first user equipment to the interfering cell is less than the first threshold, the first user equipment is in a coordinated state. The foregoing is only one way of determining that the first user equipment is in a coordinated state. The embodiment of the present invention is not limited thereto, and the present invention does not limit the manner in which the first user equipment is in a coordinated state.

The first threshold is used to distinguish whether the first user equipment is in a coordinated state, that is, the first user equipment is an intra-site edge user or an intra-site central user, and the first threshold is a positive number. It can be set by itself in the specific implementation. This embodiment does not limit the size of the first threshold. For example, the first threshold can be 6dB.

In this embodiment, when the difference between the signal strength of the first user equipment and the serving cell and the signal strength of the first user equipment to the interfering cell is less than the first threshold, the first user equipment is in a coordinated state, that is, the first The user equipment is at the edge of the cell and is an intra-site edge user.

In this embodiment, the serving cell is a serving cell of the first user equipment, and the interference cell is a cell that causes interference to the first user equipment in a cell other than the serving cell in the base station where the serving cell is located.

Step 102: The first user equipment obtains a second channel matrix of the first user equipment to the interfering cell by using channel estimation, and calculates a best pairing indication of the first user equipment for the interfering cell according to the second channel matrix (Best Companion Indicator) (hereinafter referred to as BCI), and according to the BCI, calculate the second CQI of the first user equipment when the interfering cell provides interference avoidance for the first user equipment.

Specifically, the second CQI of the first user equipment may be: when the foregoing interfering cell provides interference avoidance for the first user equipment, the first user equipment calculates that the PCI of the user equipment scheduled by the interfering cell is equal to the foregoing BCI. The second CQI of the first user equipment.

Step 103: The first user equipment feeds back one or a combination of the PCI, the BCI, the first CQI, and the second CQI, and the difference between the second CQI and the first CQI to the base station where the serving cell is located.

In this embodiment, the first user equipment indicates one or a combination of the difference between the PCI, the BCI, the first CQI, and the second CQI, and the second CQI and the first CQI by 13 bits.

In a specific implementation, the first user equipment may perform feedback according to the feedback mode indication obtained in advance, where the feedback mode indication may be sent by the network side device (for example, a radio network controller) to the first user equipment by using configuration signaling. Or the feedback mode indication may be pre-configured in the first user equipment.

In an implementation manner of this embodiment, the feedback mode indication may indicate the first user equipment When the first channel quality indicator is less than the second threshold, the PCL BCI, the first CQI, and the second CQI are fed back, or the PCI, the BCI, and the first CQI are fed back, and the difference between the second CQI and the first CQI is When a channel quality indicator is greater than or equal to a second threshold, the PCI and the first CQI are fed back. The second threshold value is a positive number, and can be set by itself in a specific implementation. The size of the second threshold is not limited in this embodiment. For example, the second threshold can be 15.

In another implementation manner of this embodiment, the feedback mode indication may indicate that the first user equipment feeds back the first CQI and the second CQI according to a predetermined ratio. For example, assuming that the predetermined ratio is 2:1, the first user equipment feeds back a second CQI after feeding back the two first CQIs.

The foregoing is only two examples for the first user equipment to perform feedback according to the feedback mode indication. The embodiment of the present invention is not limited thereto. The method for the first user equipment to perform feedback according to the feedback mode indication is not limited.

In addition, in this embodiment, when the first user equipment is in the cooperative state, the first user equipment is an intra-site central user, and the first user equipment obtains the first channel of the first user equipment to the serving cell by using channel estimation. After the matrix, the optimal PCI of the first user equipment and the secondary PCI of the first user equipment are calculated according to the first channel matrix, and the third CQI corresponding to the optimal PCI is calculated according to the optimal PCI, and according to the foregoing suboptimal The PCI calculates the fourth CQI corresponding to the sub-optimal PCI.

If the difference between the third CQI and the fourth CQI is greater than or equal to the third threshold, the first user equipment feeds back the optimal PCI and the third CQI to the base station;

If the difference between the third CQI and the fourth CQI is less than the third threshold, the first user equipment feeds back the difference between the optimal PCI, the third CQI, and the sub-optimal PCI, and the third CQI and the fourth CQI to the base station. .

Specifically, the first user equipment is in a cooperative state, where the first user equipment is: when the difference between the signal strength of the first user equipment and the serving cell and the signal strength of the first user equipment to the interfering cell is greater than or equal to the first threshold, the first user equipment In a collaborative state. The foregoing is only one way of determining that the first user equipment is in a coordinated state. The embodiment of the present invention is not limited thereto, and the present invention does not limit the manner in which the first user equipment is in a cooperative state.

In this embodiment, the third threshold is a positive number, and can be set by itself in a specific implementation. The size of the third threshold is not limited in this embodiment. For example, the third threshold can be 3.

In this embodiment, when the optimal PCI, the third CQI, and the sub-optimal PCI, and the difference between the third CQI and the fourth CQI are fed back, the first user equipment indicates the optimal PCI and the sub-optimal by 3 bits. PCI.

When the optimal PCI and the third CQI are fed back, the first user equipment indicates the above-mentioned optimal PCI and the third CQI by 13 bits; when the optimal PCI, the third CQI and the sub-optimal PCI are fed back, and the third CQI and the fourth CQI are fed back When the difference is different, the first user equipment indicates the optimal PCI, the third CQI, and the sub-optimal PCI, and the difference between the third CQI and the fourth CQI by 13 bits.

In this embodiment, when the first user equipment is in the coordinated state, and the first user equipment is scheduled, the PCI of the user equipment scheduled by the interfering cell is equal to the BCI of the user equipment scheduled by the interfering cell.

In the above embodiment, when the first user equipment is in the coordinated state, the first user equipment obtains the first channel matrix of the first user equipment to the serving cell, calculates the PCI, and when the interfering cell is not provided by the first user equipment, a first CQI when the interference is avoided; then, the first user equipment obtains a second channel matrix of the first user equipment to the interfering cell, and calculates a BCI of the first user equipment for the interfering cell, and when the interfering cell is the first user The device provides a second CQI of the first user equipment when the interference is avoided; when the second CQI is greater than the first CQI, the first user equipment sets the PCL BCI and the first CQI, and the second CQI, or the second CQI with the first The difference of the CQI is fed back to the base station where the serving cell is located, so that the user equipment at the cell edge can feed back the channel information of the user equipment to the serving cell and the channel information of the user equipment to the interfering cell to the base station. The base station performs coordinated scheduling on the cell under the base station, thereby improving the channel of the user equipment at the edge of the cell. Quality and communication rate.

In the embodiment shown in FIG. 1 of the present invention, the base station may be a Node B (NodeB), and the specific form of the base station is not limited in the present invention.

For the user U, the monthly service cell of the user U is the cell A, and the cell with the greatest interference to the user U in the cell other than the cell A under the NodeB where the cell A is located is the cell B. If the difference between the signal strength of the user U and the cell A and the signal strength of the user U to the cell B is less than the first threshold (for example, ndB), the user U is called an intra-site edge user, and the cell B is called a user. Interfering cell of U. If the difference between the signal strength of the user U to the cell A and the signal strength of the user U to the cell B is greater than or equal to the first threshold (for example, ndB), the user U is the intra-site central user.

The following describes the channel information feedback methods of intra-site central users and intra-site edge users.

If the user U is an intra-site central user, the user U obtains himself to the moon by channel estimation. After the channel H of the cell, after obtaining H, the user U can select a codebook capable of maximizing the power of the received signal from the precoding codebook set C = { _Wl , _W2 , _W3 , w ₄ } as the first precoding. Vector, calculating the optimal PCI of the user U according to the first precoding vector and H, wherein the calculation method of the PC3⁄4 can be as shown in the formula (1);

PCI, = arg max(||H · (l _L ® w ^H )f) ( 1 ) In equation (1), 1 _£ is the unit matrix of 1^, and ® is Kronecker product, |v ² is the second-order norm of the vector V, and ^ is the conjugate transpose of ^.

Secondly, the user U calculates the CQI corresponding to the optimal PCI according to the information such as the optimal PCI and the neighbor cell interference, and records it as C(3⁄4.

Then, the user U calculates its own sub-optimal PCI record as PCI ₂ , as shown in the formula (2); and calculates the CQI corresponding to the sub-optimal PCI as CQI ₂ according to information such as the sub-optimal PCI and the neighbor cell interference.

PCI ₂ = arg max(||H - (I _L ®w ^ff )|| ² ) ( 2 ) The meanings of the parameters in equation (2 ) are the same as those in equation (1 ), and are not described here. . It can be seen from the formula (2) that the PCI ₂ is a second precoding vector selected by the user U from the set C after removing the first precoding vector to maximize the power of the received signal, as the second precoding vector. Sub-optimal PCI for coding vectors and H calculations.

For example, when deltaCQI = CQI "CQI ₂ > 3, user U will feed PC3⁄4, C (3⁄4 to

NodeB; otherwise user U simultaneously feeds PC3⁄4, CQIi, PCI ₂ and deltaCQL to NodeB

The precoding codebook set in UMTS is shown in Table 1, and the spatial orthogonality between the codebooks is as shown in Table 2 below.

w. · w . w ₂ w ₃ w ₄

1.0000 0.5000 0.5000 0.0000 w ₂ 0.5000 1.0000 0.0000 0.5000 w ₃ 0.5000 0.0000 1.0000 0.5000 w ₄ 0.0000 0.5000 0.5000 1.0000 As can be seen from Table 2, {w ₂ , w ₃ } and { _Wl , w ₄ } in the precoding codebook set of UMTS are respectively orthogonal in 2x2 space. base. According to the matrix knowledge, if, orthogonal, then

|Η| ² = |Η·(Ι ® Ο『+|Η·(Ι ® Ο『, so according to the definition of optimal PCI and sub-optimal PCI, optimal PCI and sub-optimal PCI cannot be simultaneously at {w ₂ In , w ₃ }, it is also impossible to simultaneously in { _Wl , w ₄ }, that is, a user's optimal PCI and sub-optimal PCI are derived from these two orthogonal bases, respectively.

According to the nature of the above-mentioned optimal PCI and sub-optimal PCI, when user U needs to simultaneously feed PC3⁄4, CQIi, PCI ₂ and deltaCQI, only 3 bits bl^ can be expressed. (3⁄4 and ? 1 ₂ : respectively represent the index of 1 ₁ and ? 〇 _{1 2} in the orthogonal basis {w ₂ , w ₃ } and the orthogonal basis { _Wl , w ₄ }, b ₃ denotes the PCI Orthogonal basis (ie, 1 bit indicates? (3⁄4 is in orthogonal basis {w ₂ , w ₃ } or in orthogonal basis {^ ₄ }). Table 3 shows when b corpse 1 represents orthogonal basis {w ₂ w ₂ is selected in w ₃ }, b ₂ = l indicates that the orthogonal basis { _Wl , w ₄ } is selected, and b ₃ = l indicates that the orthogonal basis {w ₂ , w ₃ } is passed through 3 Bit t represents an implementation of PC3⁄4 and PCI ₂ .

table 3

If the user U is an intra-site edge user, after obtaining the channel H of the user U to the serving cell through channel estimation, the user U first calculates the PCI of the user U according to the formula (1), and calculates the interference cell according to the PCI. CQI when interference avoidance is not performed for user U, denoted as CQI CQI _X ≥\5, indicating that user U's performance is better, the interfering cell does not need to provide additional interference avoidance measures for the user U, user U will PCI and C (3⁄4 feedback to NodeB; and if (: ρ/^15 Then, the user U estimates the channel H _{mta of} the user U to the interfering cell, which is recorded as an interference channel. If the multipath number of the interference channel is L, the interference channel H _mt ^ can be represented as a 2 x 2L matrix:

H = " (.) ₂ (

/3⁄4 ₂ (J-1)1 _{( 3 )} m ^terf ~[ h _2l ( ) ₂₂ ( ■■■ /? ₂₁ (Ji) h ₂₂₂ ((JL-_ 1l))"

In the formula (3), /^ (A) represents the channel coefficient of the k-1th path between the i-th transmit antenna of the interfering cell and the jth receive antenna of the user U;

Second, the user U calculates the BCI of the user U for the interfering cell according to the interference channel, such as o.

Formula (4).

BCI = _argmin (||H _mter · (l _L ®w ^H )f) ( 4 ) The meaning of each parameter in equation (4) has the same meaning as the same parameter in equation (1), and will not be described here.

Again, the user U calculates that the CQI of the user U is equal to the BCI when the PCI of the user scheduled by the interfering cell is equal to the BCI (ie, the interfering cell provides interference avoidance for the user U), and is recorded as CQI ₂ ; if the interfering cell's dry 4 avoidance measure is invalid, That is, ddtaCQI = CQI ₂ - CQI, < 0, then user U feeds PCI and CQ back to NodeB; if the interference avoidance measure of the interfering cell is valid, ie ddtaCQI = CQI ₂ - CQI, ≥ 0, user U will PCI, BCI, (3⁄4 and deltaCQI are fed back to NodeB. In order to reduce the amount of feedback required during feedback, deltaCQI can be limited. When ddtaCQI > 16, let deltaCQI = 16. When user U feeds back PCI, BCI, (3⁄4 and deltaCQI) The user U has the following two states:

(1) Uncooperative status:

The interfering cell of the user U does not follow the criterion of the BCI of the user that the user is scheduled to be equal to the BCI of the user U, and the CQI of the user U is

(2) Collaboration status:

The interfering cell of the user U follows the criterion that the PCI of the user to which the user is scheduled is equal to the BCI fed back by the user U, and the CQI of the user U is CQI ₂ .

The specific format of the feedback in the present invention will be described below.

From the above feedback scheme, it can be seen that there are three ways for users to feedback: Feedback method 1: Feedback PCI and CQ;

deltaCQI = CQIi - CQI ₂ ≥ 3 intra-site central users, C (3⁄4 > 15 intra-site edge users, deltaCQI = CQI ₂ - CQIi <0 intra-site edge users) feedback in this way. The possible user feedback results in the feedback mode are 4 X 31 = 124, of which PCI has 4 possibilities, (3⁄4 has 31 possibilities.

Feedback method 2: Feedback PCI PCI ₂ ,

The intra-site central user of deltaCQI = CQIi - CQI ₂ < 3 uses this method for feedback. The possible user feedback results in this feedback method are 8 X 31 χ 4 = 992 types.

There are 8 possibilities (as shown in Table 3). (^1 ₁ has 31 possibilities, deltaCQI has 4 possibilities.

Feedback method 3: Feedback PCI, BCI,

deltaCQI = CQI ₂ - intra-site edge users with CQIi ≥ 0 use this method for feedback. The possible user feedback results in this feedback method are 4 4 16 16 = 4096, of which PCI and BCI have 4 possibilities, and CQI^odeltaCQI has 16 possibilities.

Therefore, all possible feedback results of the user are 124 + 992 + 4096 = 5212, and need n = log ₂ (5212) = 12.3222 bits to distinguish, so in the present invention, the user needs 13 bits for feedback.

A reference feedback format is given below:

Assume that the 13 bits used by the user feedback are denoted as c0, cl, c2, c3, c4, c5, c6, c7, c8, c9, cl0, cl l and cl2, respectively.

The binary number of the lower 11 bits of 13 bits is Co:

C ₀ =c2c3c4c5c6c7c8c9cl0cl lcl2„

If 0 ≤ (:. < 31, indicating that the user uses feedback mode one, then cOcl means PCI, CQI corpse C _0. If 31 ≤ (:. < 279, indicating that the user uses feedback mode two, then c0 corresponds to t^ , cl corresponds to b ₂ . Remember ( = (.- 31 , b ₃ = fl or(^) , where floor(x) means rounding down the non-negative number 。. Note C ₂ 124) , where mod( x, y) means that the integer x takes the remainder y, then

CQI corpse d (C ₂ , 31 ) , deltaCQI = floor (^). If 279 ≤ (:. < 1303, indicating that the user uses feedback mode three, then cOcl means PCI. Remember Q = C ₀ -279, then BCI = floor(C ₁ , 256). C ₂ = mod(C ₁ , 256), then CQ = Mod(C ₂ , 16) , deltaCQI = floori^).

16

In the present invention, the same NodeB uses the principle of cooperative scheduling. Each NodeB uses a central scheduler to complete user scheduling according to certain criteria (for example, proportional fairness, etc.), and the following conditions should be met during scheduling:

(1) Only the current scheduling result of the interfering cell of the intra-site edge user satisfies PCI and

It is possible for an intra-site edge user who is in a collaborative state to be selected when BCI pairing is required. among them

The PCI and BCI pairing requirements are as follows: Users who interfere with cell scheduling use the same PCI, and

PCI and intra-site edge user feedback BCI.

(2) For each cell, if it needs to provide interference avoidance for an intra-site edge user, the cell can only schedule users that can meet the PCI and BCI pairing requirements, that is, the cell can only schedule feedback PCI = BCI. user.

The method provided by the present invention will be described below by way of a specific example.

Assume that the UMTS system includes 7 NodeBs, and each NodeB has 3 cells, each of which covers 8 users.

First, the user determines whether it is an intra-site edge user based on the measurement result.

Specifically, for each user, first, the serving cell is referred to as cell A, and then the cell with the largest interference to the user in the other cells under the NodeB where the cell A is located is determined as ^ if the user sends a signal to the cell A. If the difference between the strength and the signal strength to the cell B is less than 6 dB, the user is an intra-site edge user, otherwise the user is an intra-site central user.

Second, the user feeds back the PCI and CQI related information to the NodeB.

When the user is an intra-site central user, after obtaining its own channel H to the serving cell through channel estimation, first calculate its own optimal PCI record as PCI PCI, = arg max(||H - (l _L ® w ^H ), and calculate the CQI corresponding to PC3⁄4 as CQI _l and then calculate the sub-optimal PCI of the user as PCI ₂ , PCI ₂ = arg max( H - (I _L ® w ^ff )|| ² ), and calculate the sub-optimal PCI The corresponding CQI is recorded as CQI _2. When deltaCQI = CQI, - CQI ₂ ≥ 3, the user feeds PC^ and C (3⁄4 to the NodeB; otherwise the user feeds back to the NodeB PC3⁄4, CQIi, PCI ₂ and deltaCQI.

When the user is an intra-site edge user, after obtaining the channel H to the serving cell through channel estimation, first calculate its own PCI, = arg max(||H - (I _i ® w ^fi )|| ² ), and Calculate when the interference is small If the zone does not perform CQI for interference avoidance, it is recorded as CQI _. If (: ρ/, ≥15, the edge user is considered to have better performance, and the interfering cell does not need to provide additional interference avoidance measures. The user will Feedback to the NodeB; otherwise the edge user estimates its channel H _mta to the interfering cell, denoted as the interference channel, and finds the BCI of the edge user for the interfering cell according to the interference channel: 5 = arg min(||H _mter - (I _i ® w ^H )), and find that the PCI of the user scheduled to interfere with the cell is equal to

The CQI of the edge user when the BCI (that is, the interference cell provides interference avoidance for the edge user) is recorded as CQI ₂ , and if the dry 4 special avoidance measure is invalid, that is, ddtaCQI = CQI ₂ - CQI, < 0, the user will PCI and C (3⁄4 feedback to NodeB; otherwise the user will PCI, BCI, . (3⁄4 and (16 〇01 feedback to NodeB.

Finally, the central scheduler of each NodeB performs coordinated scheduling for the next three cells. FIG. 2 is a flowchart of an embodiment of the user scheduling method according to the present invention. In this embodiment, a user scheduling method based on a greedy algorithm and a proportional fairness criterion is used. As shown in FIG. 2, the user scheduling method may include:

Step 201: Initialize the selected user set to an empty set.

The weights obtained by the PF criterion are sorted in descending order to obtain the sequence PFQueue, and the iteration variable j = l is initialized.

One central user who feedbacks the optimal PCI and the sub-optimal PCI corresponds to two virtual users, that is, the optimal PCI and the sub-optimal PCI respectively correspond to different virtual users, and the two states of one edge user (cooperated state and not The collaborative state) also corresponds to two virtual users.

Step 203: Determine whether the iteration variable j is greater than the length of the PFQueue, and if yes, the scheduling process ends; otherwise, execute step 204.

Step 204: Obtain a serving cell of the jth user in the PFQueue, and determine, according to the current scheduling result of the serving cell, whether the jth user has been scheduled. If yes, go to step 211; otherwise, go to step 205.

Step 205: Determine, according to the current scheduling result of the serving cell, whether the foregoing jth user can be scheduled when the PCI and BCI pairing restriction is not considered. If not, execute step 211; otherwise, perform step 206.

Step 206: Determine whether the jth user is an intra-site edge user in a coordinated state. If yes, execute step 207; otherwise, perform step 208. Step 207: Calculate an interfering cell index of the jth user, and determine, according to the BCI information of the jth user and the scheduling result of the current interfering cell, whether the current interfering cell scheduling result meets the PCI and BCI pairing requirements, and if yes, perform the step 208; If the PCI and BCI pairing requirements are not met, step 211 is performed.

Step 208: Determine, according to the scheduling result of all the cells in the current site, whether the serving cell of the jth user needs to provide interference avoidance for the intra-site edge users of other cells. If yes, go to step 209; otherwise, go to step 210.

Step 209: According to the current user service cell, the PCI and BCI pairing for the interference avoidance of the intra-site edge user of the other cell is required to determine whether the current user meets the PCI and BCI pairing condition. If not, step 211 is performed; otherwise, step 210 is performed.

Step 210: The jth user is selected, and step 211 is performed.

Step 211: Update the iteration variable j = j + l , and perform step 203.

The present invention is mainly directed to the fact that in the conventional UMTS system, since there is no interference avoidance for the user at the cell edge, the user at the cell edge is subjected to interference comparable to the received signal, causing the CQI of the user at the cell edge to decrease. A feedback method of channel information is proposed for the problem that the data rate that can be received is also reduced.

In the present invention, the edge user can obtain the channel information between the interfering cells and the information information between the inter-cell and the serving cell through the channel estimation. According to the channel information, the edge user can find out from the pre-coded codebook that the interfering cell can be Given the precoding vector with the least interference, the index in the precoding codebook of the precoding vector is BCI. After the user feeds the BCI back to the NodeB, if the edge users in the coordinated state are scheduled, the interfering cell can provide interference avoidance to the edge user by the user who only schedules the feedback PCI=BCI. the goal of. It can be seen from the above principles that when a cell needs to provide interference avoidance for an edge user, it can only schedule users with PCI = BCI, which limits the degree of freedom of user scheduling. In order to alleviate this limitation, for the central user, if the CQI difference between the optimal PCI and the sub-optimal PCI is not large (for example, less than 3), the central user will feed back the optimal PCI and the sub-optimal PCI. NodeB, to increase the freedom of user scheduling.

The comparison between the UMTS system using intra-site co-scheduling and the UMTS system using single-cell scheduling in cell throughput, worst cell 5% user throughput, and intra-site edge user throughput is given below. In a UMTS system using single cell scheduling, a single cell is based on a greedy algorithm and The user scheduling algorithm of the proportional fairness criterion, FIG. 3 is a flowchart of another embodiment of the user scheduling method of the present invention. As shown in FIG. 3, the user scheduling method may include:

Step 301: Initialize the selected user set as an empty set.

In step 302, the weights obtained by all users according to the PF criterion are sorted in descending order to obtain a sequence PFQueue, and the iteration variable j = l is initialized.

Where PFQueue(i) represents the user with the largest weight.

Step 303: Determine whether the iteration variable j is greater than the length of the PFQueue. If yes, the scheduling process ends; otherwise, obtain the jth user in the PFQueue, and perform step 304.

Step 304: Determine whether the sum of the number of high-speed physical downlink shared channels (hereinafter referred to as HS-PDSCH) of the j-th user and the number of HS-PDSCHs of the scheduled users of the cell is greater than 15, if yes, execute Step 307; otherwise, step 305 is performed.

Step 305, the jth user is selected.

Step 306: Determine whether the number of scheduled users in the current scheduling result is greater than or equal to 4, or whether the sum of the number of HS-PDSCHs occupied by the user is greater than or equal to 15; if yes, the scheduling process ends; otherwise, step 307 is performed.

Step 307: Update the iteration variable j = j + l , and perform step 303.

The comparison between the average throughput rate of the cell and the worst 5% of the cell can be shown in Table 4.

The edge user throughput ratio under intra-site can be compared as shown in Table 5.

Table 4 and Table 5 show the UMTS system using intra-site co-scheduling and the UMTS system using single-cell scheduling in the cell throughput rate, the worst 5% user throughput rate and the intra-site edge. Comparing the throughput of households, it can be seen from Table 4 and Table 5 that after adopting the intra-site coordinated scheduling scheme, the worst 5% user throughput rate and the intra-site edge user throughput rate of the cell are significantly improved. The average throughput rate of the cell users is not affected, which indicates that the present invention can effectively improve the throughput rate of the edge users without affecting the throughput rate of the cell users.

One of ordinary skill in the art will appreciate that all or part of the steps to implement the various method embodiments described above can be accomplished by hardware associated with the program instructions. The aforementioned program can be stored in a computer readable storage medium. The program, when executed, performs the steps including the above-described method embodiments; and the foregoing storage medium includes: a medium that can store program codes, such as a ROM, a RAM, a magnetic disk, or an optical disk.

4 is a schematic structural diagram of an embodiment of a user equipment according to the present invention. The user equipment in this embodiment may implement the process of the embodiment shown in FIG. 1 of the present invention. The user equipment in this embodiment may be the first user equipment.

As shown in FIG. 4, the user equipment may include: an obtaining module 41, a calculating module 42 and a feedback module 43;

An obtaining module 41, configured to obtain, by using channel estimation, a first channel matrix of the first user equipment to the serving cell when the first user equipment is in a coordinated state; and obtain a second channel of the first user equipment to the interfering cell by using channel estimation Matrix

Specifically, the first user equipment in the coordinated state may be: when the difference between the signal strength of the first user equipment to the serving cell and the signal strength of the first user equipment to the interference cell is less than a first threshold, the first The user equipment is in a coordinated state. The foregoing is only one way of determining that the first user equipment is in a coordinated state. The embodiment of the present invention is not limited thereto, and the present invention does not limit the manner in which the first user equipment is in a coordinated state.

The first threshold is used to distinguish whether the first user equipment is in a coordinated state, that is, the first user equipment is an intra-site edge user or an intra-site central user, and the first threshold is a positive number, which may be implemented in a specific implementation. When the time is set by itself, the size of the first threshold is not limited in this embodiment. For example, the first threshold can be 6dB.

In this embodiment, the serving cell is a serving cell of the first user equipment, and the interference is small. The area is the cell that causes the first user equipment to have the greatest interference among the other cells except the serving cell in the base station where the serving cell is located.

The second threshold value is a positive number, which can be set in a specific implementation. The size of the second threshold is not limited in this embodiment. For example, the second threshold can be 15.

The calculating module 42 is configured to calculate a precoding control indication of the first user equipment according to the first channel matrix obtained by the obtaining module 41, and calculate, according to the precoding control indication, when the interfering cell does not provide interference avoidance for the first user equipment a channel quality indicator; and calculating, according to the second channel matrix obtained by the obtaining module 41, a best pairing indication of the first user equipment for the interfering cell, and calculating, according to the best pairing indication, when the interfering cell provides interference avoidance for the first user equipment The second channel quality indicator of the first user equipment.

Specifically, the calculating module 42 may calculate a second channel quality indicator of the first user equipment when the precoding control indication of the user equipment scheduled by the interfering cell is equal to the best pairing indication.

The feedback module 43 is configured to feed back one of a difference between the precoding control indication, the best pairing indication, the first channel quality indicator, and the second channel quality indicator, and the difference between the second channel quality indicator and the first channel quality indicator to The base station where the above serving cell is located.

Specifically, the feedback module 43 may indicate, by using 13 bits, the foregoing precoding control indication, the best pairing indication, the first channel quality indicator, and the second channel quality indicator, and the difference between the second channel quality indicator and the first channel quality indicator. One or a combination.

In an implementation manner of this embodiment, the obtaining module 41 is further configured to: when the first user equipment is in the cooperative state, obtain the first channel matrix of the first user equipment to the serving cell by using channel estimation;

The first user equipment is in a cooperative state, where: when the difference between the signal strength of the first user equipment and the serving cell and the signal strength of the first user equipment to the interfering cell is greater than or equal to the first threshold, the first user equipment is Collaboration status. The foregoing is only one way of determining that the first user equipment is in a cooperative state, and the embodiment of the present invention is not limited thereto. The method for determining that the first user equipment is in a cooperative state is not limited.

The calculating module 42 is further configured to calculate, according to the first channel matrix obtained by the obtaining module 41, an optimal precoding control indication of the first user equipment and a suboptimal precoding control indication of the first user equipment, and according to the foregoing optimal precoding control And instructing to calculate a third channel quality indicator corresponding to the optimal precoding control indication, and calculating a fourth channel quality indicator corresponding to the suboptimal precoding control indication according to the foregoing suboptimal precoding control indication. The feedback module 43 is further configured to: when the difference between the third channel quality indicator and the fourth channel quality indicator is greater than or equal to the third threshold, feed back the optimal precoding control indication and the third channel quality indicator to the base station; When the difference between the third channel quality indicator and the fourth channel quality indicator is less than the third threshold, the optimal precoding control indication, the third channel quality indicator, and the suboptimal precoding control indication, and the third channel quality indicator are The difference of the fourth channel quality indication is fed back to the above base station.

Specifically, the feedback module 43 may represent the optimal precoding control indication, the third channel quality indicator, and the suboptimal precoding control indication, and the difference between the third channel quality indicator and the fourth channel quality indicator, by using 3 bits. The above optimal precoding control indication and the above suboptimal precoding control indication.

The feedback module 43 may represent the optimal precoding control indication and the third channel quality indicator by 13 bits when feeding back the optimal precoding control indication and the third channel quality indication; when feeding back the optimal precoding control indication, the third channel quality And indicating the optimal precoding control indication, the third channel quality indicator, and the suboptimal precoding control indication by 13 bits when the indication and the suboptimal precoding control indication, and the difference between the third channel quality indicator and the fourth channel quality indicator are And a difference between the third channel quality indicator and the fourth channel quality indicator.

In the above user equipment, when the first user equipment is in the coordinated state, after the obtaining module 41 obtains the first channel matrix of the first user equipment to the serving cell, the calculating module 42 calculates a precoding control indication, and when the interfering cell is not The first user equipment provides a first channel quality indicator when the interference is avoided; then, the obtaining module 41 obtains the second channel matrix of the first user equipment to the interfering cell, and the calculating module 42 calculates the best that the first user equipment is for the interfering cell. a pairing indication, and a second channel quality indicator of the first user equipment when the interfering cell provides interference avoidance for the first user equipment; the feedback module 43 sets the precoding control indication, the best pairing indication, the first channel quality indicator, and the second The channel quality indicator, and one or a combination of the difference between the second channel quality indicator and the first channel quality indicator, is fed back to the base station where the serving cell is located; thus, the user equipment at the cell edge can implement the channel of the user equipment to the serving cell. Information, and the channel of the user equipment to the interfering cell The information is fed back to the base station for the base station to perform coordinated scheduling on the cells under the base station, thereby improving channel quality and communication rate of the user equipment at the cell edge.

Those skilled in the art will appreciate that the drawings are only schematic representations of a preferred embodiment, in which The modules or processes are not necessarily required to practice the invention.

Those skilled in the art can understand that the modules in the apparatus in the embodiments may be distributed in the apparatus of the embodiment according to the embodiment, or may be correspondingly changed in one or more apparatuses different from the embodiment. The modules of the above embodiments may be combined into one module, or may be further split into a plurality of sub-modules.

It should be noted that the above embodiments are merely illustrative of the technical solutions of the present invention, and are not intended to be limiting; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art The technical solutions described in the foregoing embodiments may be modified, or some or all of the technical features may be equivalently replaced; and the modifications or substitutions do not deviate from the technical solutions of the embodiments of the present invention. range.

Claims

Rights request

A channel information feedback method, comprising:

The method according to claim 1, wherein the being in the coordinated state of the first user equipment comprises:

And when the difference between the signal strength of the first user equipment to the serving cell and the signal strength of the first user equipment to the interfering cell is less than a first threshold, the first user equipment is in a coordinated state.

3. The method of claim 1 wherein:

The first user equipment indicates, by 13 bits, the precoding control indication, the best pairing indication, the first channel quality indicator, and the second channel quality indicator, and the second channel quality indicator and One or a combination of differences in the first channel quality indication.

The method according to any one of claims 1-3, wherein the calculating, according to the best pairing indication, the first when the interfering cell provides interference avoidance for the first user equipment The second channel quality indicator of the user equipment includes:

The first user equipment calculates a second channel quality indicator of the first user equipment when the precoding control indication of the user equipment scheduled by the interfering cell is equal to the best pairing indication.

The method according to claim 1, further comprising: when the first user equipment is in a cooperative state, the first user equipment obtains the first user equipment to the service by using channel estimation After the first channel matrix of the cell, calculating an optimal precoding control indication of the first user equipment and a suboptimal precoding control indication of the first user equipment according to the first channel matrix, and according to the optimal The precoding control indicates that the third channel quality indicator corresponding to the optimal precoding control indication is calculated, and the fourth channel quality indicator corresponding to the suboptimal precoding control indication is calculated according to the suboptimal precoding control indication;

If the difference between the third channel quality indicator and the fourth channel quality indicator is greater than or equal to a third threshold, the first user equipment uses the optimal precoding control indication and the third channel quality Instructing feedback to the base station;

If the difference between the third channel quality indicator and the fourth channel quality indicator is less than a third threshold, the first user equipment, the optimal precoding control indication, the third channel quality indicator, and And the sub-optimal precoding control indication, and the fourth channel quality indicator, or the difference between the third channel quality indicator and the fourth channel quality indicator is fed back to the base station.

The method according to claim 5, wherein the first user equipment is in a cooperative state, including:

The first user equipment is in a cooperative state when a difference between a signal strength of the first user equipment to the serving cell and a signal strength of the first user equipment to the interference cell is greater than or equal to a first threshold.

7. The method of claim 5, wherein

When the optimal precoding control indication, the third channel quality indicator, and the suboptimal precoding control indication, and the difference between the third channel quality indicator and the fourth channel quality indicator are fed back, The first user equipment indicates the optimal precoding control indication and the suboptimal precoding control indication by 3 bits.

8. A method according to any of claims 5-7, characterized in that

When the optimal precoding control indication and the third channel quality indicator are fed back, the first user equipment indicates the optimal precoding control indication and the third channel quality indication by 13 bits;

When the optimal precoding control indication, the third channel quality indicator, and the suboptimal precoding control indication, and the difference between the third channel quality indicator and the fourth channel quality indicator are fed back, The first user equipment indicates the optimal precoding control indication by 13 bits. Determining a third channel quality indicator and the sub-optimal precoding control indication, and a difference between the third channel quality indicator and the fourth channel quality indicator.

9. The method of claim 1 wherein:

When the first user equipment is scheduled, the precoding control indication of the user equipment scheduled by the interfering cell is equal to the best pairing indication of the user equipment scheduled by the interfering cell.

A user equipment, wherein the user equipment is a first user equipment, and the user equipment includes: an obtaining module, a calculating module, and a feedback module;

a calculation module, configured to calculate, according to the first channel matrix obtained by the obtaining module, a precoding control indication of the first user equipment, and calculate, according to the precoding control indication, that the interfering cell is not the first user The device provides a first channel quality indicator when the interference is avoided; and calculating, according to the second channel matrix obtained by the obtaining module, the best pairing indication of the first user equipment for the interfering cell, and according to the best pairing indication Calculating a second channel quality indicator of the first user equipment when the interfering cell provides interference avoidance for the first user equipment, and a feedback module, configured to: the precoding control indication, the best pairing indication, The first channel quality indicator and the second channel quality indicator, and one or a combination of the difference between the second channel quality indicator and the first channel quality indicator are fed back to the base station where the serving cell is located.

11. The user equipment according to claim 10, characterized in that

The feedback module is specifically configured to indicate, by using 13 bits, the precoding control indication, the best pairing indication, the first channel quality indicator, and the second channel quality indicator, and the second channel quality indicator. One or a combination of the differences from the first channel quality indication.

The user equipment according to any one of claims 10 to 11, wherein the calculating module is specifically configured to calculate that the precoding control indication of the user equipment scheduled by the interfering cell is equal to the optimal A second channel quality indicator of the first user equipment when pairing the indication.

13. The user equipment according to claim 10, wherein

The obtaining module is further configured to obtain, by using channel estimation, a first channel matrix of the first user equipment to the serving cell when the first user equipment is in a cooperative state; The calculating module is further configured to calculate an optimal precoding control indication of the first user equipment and a suboptimal precoding control indication of the first user equipment according to the first channel matrix obtained by the obtaining module, and according to the The optimal precoding control indicates that the third channel quality indicator corresponding to the optimal precoding control indication is calculated, and the fourth channel quality corresponding to the suboptimal precoding control indication is calculated according to the suboptimal precoding control indication Instruction

The feedback module is further configured to: when the difference between the third channel quality indicator and the fourth channel quality indicator is greater than or equal to a third threshold, the optimal precoding control indication and the third And the channel quality indicator is fed back to the base station; and when the difference between the third channel quality indicator and the fourth channel quality indicator is less than a third threshold, the optimal precoding control indication, the third And indicating, by the channel quality indicator and the suboptimal precoding control indication, a difference between the third channel quality indicator and the fourth channel quality indicator to the base station.

14. The user equipment according to claim 13, wherein

The feedback module is specifically configured to: when the optimal precoding control indication, the third channel quality indicator, and the suboptimal precoding control indication are fed back, and the third channel quality indicator and the fourth channel The difference between the quality indications indicates the optimal precoding control indication and the suboptimal precoding control indication by 3 bits.

15. The user equipment according to claim 13 or 14, wherein

The feedback module is specifically configured to: when the optimal precoding control indication and the third channel quality indicator are fed back, represent the optimal precoding control indication and the third channel quality indicator by 13 bits; And feeding back the optimal precoding control indication, the third channel quality indicator, and the suboptimal precoding control indication, and the difference between the third channel quality indicator and the fourth channel quality indicator, by using 13 The bits represent the optimal precoding control indication, the third channel quality indicator and the suboptimal precoding control indication, and a difference between the third channel quality indicator and the fourth channel quality indicator.