CN102457855B - Interference coordination method and system for Femtocell - Google Patents

Interference coordination method and system for Femtocell Download PDF

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CN102457855B
CN102457855B CN201010515957.1A CN201010515957A CN102457855B CN 102457855 B CN102457855 B CN 102457855B CN 201010515957 A CN201010515957 A CN 201010515957A CN 102457855 B CN102457855 B CN 102457855B
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home enodeb
interference
subscriber equipment
training sequence
precoding
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CN102457855A (en
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侯雪颖
王大飞
沈东栋
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TD Tech Ltd
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TD Tech Ltd
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Abstract

The invention provides an interference coordination method for a Femtocell. The method comprises the following steps that: A, user equipment senses surrounding interference intensity and submits the sensed interference intensity to the Femtocell; B, the Femtocell adaptively divides frequency ranges according to the interference intensity submitted by the user equipment and randomly selects a frequency range from the divided frequency ranges to perform data transmission; C, the Femtocell sends a training sequence, and the user equipment estimates an interference and noise covariance matrix according to the training sequence from the Femtocell so as to calculate to obtain a precoding matrix as an uplink transmission precoding matrix; and D, the user equipment sends a training sequence, the Femtocell estimates an interference and noise covariance matrix according to the training sequence from the user equipment so as to calculate a precoding matrix serving as a downlink transmission precoding matrix, and returns to the step C. The invention also provides a system for implementing Femtocell interference coordination.

Description

The disturbance coordination method of a kind of Femtocell and system
Technical field
The present invention relates to mobile communication technology, particularly Home eNodeB (Femtocell) technology, relates in particular to disturbance coordination method and the system of a kind of Femtocell.
Background technology
Home eNodeB (Femtocell) claim again micro-base station, is in recent years according to the subminaturization mobile base station of 3G development and the release of mobile broadband trend.Femtocell uses IP agreement, and by broadband connections such as subscriber equipment and existing digital subscriber equipment line (DSL), local area network (LAN)s (LAN), far-end is realized the UNICOM from IP network to mobile network by dedicated gateway.The size of Femtocell equipment is similar to ADSL Modem, has the feature of easy for installation, automatic configuration, automatic network planning, plug and play.Femtocell has various standards such as being applicable to CDMA, GSM, UMTS and supports the product of 2G, 2.5G, 3G, and with other same standard in mobile household base station of operator, same to frequency range, therefore the mobile terminal such as mobile phone can be general.
The introducing of Femtocell can provide good guarantee for indoor and covering focus scene; The transmitting power of these nodes is little, is convenient to on-premise network neatly; The coverage of these nodes is little simultaneously, can utilize more easily the potential high band frequency spectrum of LTE Advanced.But, within original cell range, introduce new transmitting node, be equivalent to introduce new interference source, Inter-Cell Interference Coordination is a new challenge.Due to deployment and the unlatching of femtocell or close mainly by subscriber equipment control, thereby cause this network topology very fixing, therefore the interference between femtocell is difficult to the master controller control by network.If femtocell is full frequency multiplex, and does not adopt any disturbance coordination method, once some adjacent femtocell work simultaneously, will produce serious interference.
The direct-vision method that solves phase mutual interference between above-mentioned Femtocell is to carry out frequency partition, is similar to the frequency partition method of conventional cellular cell, and adjacent Femtocell is distributed to orthogonal frequency range, makes not interfere with each other.
Someone has proposed frequency resource allocation method (list of references: Bharucha, Z. for the femtocell scene of different base station deployment density; Haas, H.; Auer, G.; Cosovic, I.; , " Femto-Cell Resource Partitioning, " GLOBECOM Workshops, 2009 IEEE, vol., no., pp.1-6, Nov.30 2009-Dec.4 2009. and Ling, J.; Chizhik, D.; Valenzuela, R.; " On resource allocation in dense femto-deployments; " Microwaves, Communications, Antennas and Electronics Systems, 2009.COMCAS 2009.IEEE International Conference on, vol., no., pp.1-6,9-11 Nov.2009.), consider the impact of different frequency duplex factor as one on systematic function.
The advantage of this method is simple, easily operation, but shortcoming is in the time considering a highdensity Femtocell scene, needs the band number of dividing to increase, thus cause the reduction of the availability of frequency spectrum.
Somebody has proposed a kind of dynamic frequency allocation method (3GPP TR36.814 V1.7.0 on frequency partition basis, Futher Advancements for E-UTRA Phsical Layer Aspects, Feb.2010.), first Femtocell is divided in orthogonal frequency range, then send by Femtocell the new frequency range request that takies, this need to obtain the approval of adjacent Home eNodeB, Home eNodeB can be set an interference threshold, if adjacent Home eNodeB is subject to the interference of this Home eNodeB lower than thresholding in the frequency range of its request, just allow it in new frequency range, to transmit, as long as but have an adjacent Home eNodeB to be subject to the interference higher than thresholding, send refusal signal, so, it just will be prohibited from using new frequency range.
This method can realize the availability of frequency spectrum higher than hard frequency partition, but this method is largely subject to the restriction of scene, and under the stronger environment of high density phase mutual interference, performance can not improve a lot.
Summary of the invention
The invention provides the disturbance coordination method of a kind of Femtocell, the interference strength that can be subject to according to subscriber equipment is carried out adaptive frequency range division, improves to the full extent the availability of frequency spectrum.
The embodiment of the present invention proposes the disturbance coordination method of a kind of Home eNodeB Femtocell, comprises the steps:
A, subscriber equipment perception interference strength around, and the interference strength of institute's perception is reported to Home eNodeB;
B, Home eNodeB carry out adapted frequency band merge according to the interference strength of user equipment to report, and Home eNodeB is random from ready-portioned frequency range selects a frequency range to carry out transfer of data;
C, Home eNodeB send training sequence, and subscriber equipment is estimated to disturb and noise covariance battle array according to the training sequence from Home eNodeB, and then calculates pre-coding matrix as uplink precoding battle array;
D, subscriber equipment send training sequence, and Home eNodeB is estimated to disturb and noise covariance battle array according to the training sequence from subscriber equipment, and then calculates precoding battle array as downlink transfer precoding battle array, and returns to step C.
Preferably, preset different Signal to Interference plus Noise Ratio threshold value i, the corresponding corresponding frequency range divide value R of each threshold value i, threshold value is higher, the R that it is corresponding iless;
Described step B comprises:
B1, Home eNodeB be according to the statistic SINR SINR of user equipment to report, and by its SINR and default threshold value icompare, if β i< SINR < β i+1, whole bandwidth is divided into R by it isection;
B2, Home eNodeB are from R iin section frequency range, frequency range of random choose is carried out signal transmission.
Preferably, described step C comprises:
C1, Home eNodeB k be according to downlink precoding, the training sequence s that to send length be T i(n), n=1 ..., T;
C2, subscriber equipment k covariance to received signal
Figure BSA00000314828000031
carry out maximal possibility estimation, obtain wherein
Figure BSA00000314828000033
Figure BSA00000314828000034
be n and receive signal;
C3, subscriber equipment k utilize obtain interference and the noise covariance matrix B of subscriber equipment k kestimation
Figure BSA00000314828000036
C4, subscriber equipment k utilize the estimation of interference and noise covariance matrix
Figure BSA00000314828000037
calculate its reception & disposal vector u k:
Figure BSA00000314828000038
Figure BSA00000314828000039
the reception & disposal vector u that subscriber equipment k is calculated kas its up transmitting precoding,
Figure BSA000003148280000310
Figure BSA000003148280000311
Preferably, Home eNodeB and subscriber equipment have respectively M kand N kroot antenna, while execution first, step C1 is:
Home eNodeB k selects M at random k× 1 vector v at the tenth of the twelve Earthly Branches kas the downlink precoding of Home eNodeB k, r=1 ..., R i; Home eNodeB k is according to downlink precoding, the training sequence s that to send length be T i(n), n=1 ..., T.
Preferably, described step D comprises:
D1, subscriber equipment send training sequence, and Home eNodeB k estimates interference and the noise covariance matrix that it is subject to
Figure BSA00000314828000042
D2, Home eNodeB k calculate its reception & disposal vector,
Figure BSA00000314828000044
The reception & disposal vector that D3, Home eNodeB k are calculated is directly as its downlink precoding,
Figure BSA00000314828000045
Figure BSA00000314828000046
The embodiment of the present invention also proposes a kind of system that realizes Home eNodeB Femtocell interference coordination, and this system comprises Home eNodeB and subscriber equipment,
Described subscriber equipment is used for perception interference strength around, and the interference strength of institute's perception is reported to Home eNodeB; Also estimate to disturb and noise covariance battle array from the training sequence of Home eNodeB for basis, and then calculate pre-coding matrix as uplink precoding battle array, send training sequence according to described uplink precoding paroxysm;
Described Home eNodeB is for carrying out adapted frequency band merge according to the interference strength of user equipment to report, and Home eNodeB is random from ready-portioned frequency range selects a frequency range to carry out transfer of data; Home eNodeB is also estimated to disturb and noise covariance battle array from the training sequence of subscriber equipment for basis, and then calculates precoding battle array as downlink transfer precoding battle array, and send training sequence according to described downlink transfer precoding paroxysm.
Preferably, preset different Signal to Interference plus Noise Ratio threshold value i, the corresponding corresponding frequency range divide value R of each threshold value i, threshold value is higher, the R that it is corresponding iless;
Described Home eNodeB comprises:
Threshold value module, presets different Signal to Interference plus Noise Ratio threshold value for storing i, the corresponding corresponding frequency range divide value R of each threshold value i, threshold value is higher, the R that it is corresponding iless;
Frequency partition module, for by the threshold value of the SINR of user equipment to report and threshold value module stores icompare, if β i< SINR < β i+1, whole bandwidth is divided into R by it isection;
Sending module, for the R from described frequency partition Module Division iin section frequency range, frequency range of random choose is carried out signal transmission.
Preferably, described subscriber equipment comprises:
User's side joint collection of letters covariance estimation module, for covariance to received signal
Figure BSA00000314828000051
carry out maximal possibility estimation, obtain receiving the covariance estimation of signal
Figure BSA00000314828000052
wherein
Figure BSA00000314828000053
Figure BSA00000314828000054
be n and receive signal;
User's side is disturbed and noise covariance estimation module, for utilizing the covariance estimation of the reception signal that described user's side joint collection of letters covariance estimation module obtains
Figure BSA00000314828000055
obtain interference and the noise covariance matrix B of subscriber equipment kestimation
Figure BSA00000314828000056
User's side reception & disposal vector calculation module, for utilizing described user's side is disturbed and noise covariance estimation module obtains interference and the estimation of noise covariance matrix
Figure BSA00000314828000057
calculate its reception & disposal vector u k: u k = B ^ k - 1 H kk v k | | B ^ k - 1 H kk v k | | , &ForAll; k &Element; &kappa; r ;
The reception & disposal vector u that described subscriber equipment calculates described user's side reception & disposal vector calculation module kas its up transmitting precoding,
Figure BSA000003148280000511
and according to described up transmitting precoding transmitting training sequence.
Preferably, described Home eNodeB comprises:
Base station side is disturbed and noise covariance estimation module, for interference and the noise covariance matrix of estimating that Home eNodeB is subject to
Figure BSA000003148280000512
Base station side reception & disposal vector calculation module, for according to described base station side is disturbed and noise covariance estimation module obtains interference and the estimation of noise covariance matrix
Figure BSA000003148280000513
calculating reception & disposal vector, u &OverBar; k = B &LeftArrow; k - 1 H &LeftArrow; kk v &LeftArrow; k | | B &LeftArrow; k - 1 H &LeftArrow; kk v &LeftArrow; k | | , &ForAll; k &Element; &kappa; r ;
The reception & disposal vector that described Home eNodeB calculates described base station side reception & disposal vector calculation module is directly as its downlink precoding,
Figure BSA00000314828000061
Figure BSA00000314828000062
and according to described downlink precoding, the training sequence s that transmission length is T i(n), n=1 ..., T.
Preferably, when Home eNodeB sends training sequence first, select at random M k× 1 vector v at the tenth of the twelve Earthly Branches kas downlink precoding,
Figure BSA00000314828000063
r=1 ..., R i, and according to described downlink precoding, the training sequence s that transmission length is T i(n), n=1 ..., T.
As can be seen from the above technical solutions, due to the reciprocity of transceiver effect exchange and channel in up-downgoing transmitting procedure, in downlink transmission process, receiving terminal processing array is to maximize the Multiuser Detection matrix that SINR is target; And in uplink process, receiving terminal processing array just becomes to maximize the pre-coding matrix that SLNR is target.Therefore, transmit by up-downgoing, user, in improving SINR, reduces the interference to other users by improving SLNR, by the iteration of limited number of time, can realize victim compression in limited space, aims at thereby realize disturbing.
Accompanying drawing explanation
Fig. 1 is the realization flow figure of the disturbance coordination method of the Femtocell of embodiment of the present invention proposition;
Fig. 2 is 5 milliseconds of (ms) periodic frame structural representations of TDD LTE (FS 2);
Fig. 3 is the flow chart that the transceiver iteration of embodiment of the present invention proposition realizes interference coordination;
Fig. 4 is the comparison schematic diagram that the embodiment of the present invention proposes the user data rate cumulative distribution function (CDF) that obtains of disturbance coordination method and the CDF of the user data rate that does not adopt disturbance coordination method to obtain.
Embodiment
The present invention, mainly for the mutual interference problem causing between Femtocell in downlink transmission process, provides the interference coordination schemes of a kind of Femtocell.This scheme adopts adaptive disturbance technique of alignment, is mainly divided into two parts: adapted frequency band merge and distributed interference are aimed at.Provide specific implementation process below.
The realization flow of the disturbance coordination method of the Femtocell that the embodiment of the present invention proposes as shown in Figure 1, comprises the steps:
Step 101: subscriber equipment perception is interference strength around, and the interference strength of institute's perception is reported to Home eNodeB.
Step 102: Home eNodeB carries out adapted frequency band merge according to the interference strength of user equipment to report, Home eNodeB is random from ready-portioned frequency range selects a frequency range to carry out transfer of data.
Step 103: Home eNodeB sends training sequence, subscriber equipment is estimated to disturb and noise covariance battle array according to the training sequence from Home eNodeB, and then calculates pre-coding matrix as uplink precoding battle array.
Step 104: subscriber equipment sends training sequence, Home eNodeB is estimated to disturb and noise covariance battle array according to the training sequence from subscriber equipment, and then calculates precoding battle array, as downlink transfer precoding battle array.
Step 105: repeatedly perform step 103 to 104, Home eNodeB and subscriber equipment continue to be transmitted transceiver iteration by up-downgoing, realizes distributed interference and aims at.
Take the Femtocell network topology that transceiver formed by K as example, the present invention program is elaborated below.If Home eNodeB and subscriber equipment are multiaerial system, Home eNodeB and subscriber equipment have respectively M kand N kroot antenna.Whole frequency band is divided into R frequency range, uses κ r,
Figure BSA00000314828000071
..., R represents r the user device set in frequency range, if i.e. k ∈ κ r, represent that k takies r frequency range to Home eNodeB and subscriber equipment and transmits.
Under described network topology, step 102 can specifically comprise following sub-step:
Sub-step 102-1: set different Signal to Interference plus Noise Ratio (SINR) threshold value i, the corresponding corresponding frequency range divide value R of each threshold value i, threshold value is higher, the R that it is corresponding iless, bandwidth that also can user device transmissions is larger.Wherein, threshold value and frequency range divide value are to set according to actual simulating scenes and resource distribution.
Sub-step 102-2: it receives SINR by subscriber devices compute, and described SINR is reported to Home eNodeB;
Sub-step 102-3: Home eNodeB is by the SINR of user equipment to report and default threshold value icompare, if β i< SINR < β i+1, whole bandwidth is divided into R by it isection.
Sub-step 102-4: Home eNodeB is from R iin section frequency range, frequency range of random choose is transmitted.
(1) distributed interference is aimed at
Consider time division duplex (TDD) system up-downgoing channel reciprocity, and the slow feature becoming of femtocell channel, up-downgoing transmitting procedure each time can be used as to an iterative process.For instance, be illustrated in figure 2 the ascending-descending subframes of 5 milliseconds of (ms) periodic frame structural support of TDD LTE (FS 2), can be according to actual tdd frame structure, at least in a frame, can complete up-downgoing transmission, at least can realize one time iteration.And the channel of femtocell is slow change, thereby can, by the lasting transmission of up-downgoing, complete the iterative process of transceiver, realizes the successive elimination disturbing.Describe respectively descending and uplink process below, and provide transceiver iteration implementation method.
Downlink transmission process:
Home eNodeB i transmitting in r frequency range is expressed as
x i r = v i d i , &ForAll; i &Element; &kappa; r 0 , &ForAll; i &NotElement; &kappa; r , r = 1 , . . . , R
Wherein, v im i× 1 transmitting pre-coding matrix, meets
Figure BSA00000314828000082
d ibe the symbol that Home eNodeB i will transmit, meet E{||d i|| 2}=P i.
The reception signal indication of k subscriber equipment is
y k r = &Sigma; i = &kappa; r H ki x i r + w k r , &ForAll; k &Element; &kappa; r , r=1,...,R
Wherein, H kin k× M ihome eNodeB i to the channel of subscriber equipment k,
Figure BSA00000314828000085
n kthe white complex gaussian noise of × 1 obedience zero-mean unit variance.
Receiving terminal does following processing and obtains desired signal
Figure BSA00000314828000086
&ForAll; k &Element; &kappa; r , r=1,...,R
Wherein, u kn k× 1 receiving terminal processing array, a +the conjugate transpose of representing matrix a.
Ul transmissions process:
Define a reverse link, transceiver locations is exchanged, and considers TDD system up-downgoing reciprocity, and reverse link is equivalent to uplink.
Transmitting of subscriber equipment i is expressed as
x &LeftArrow; i r = v &LeftArrow; i d &LeftArrow; i , &ForAll; i &Element; &kappa; r 0 , &ForAll; i &NotElement; &kappa; r , r = 1 , . . . , R
Wherein,
Figure BSA00000314828000092
n i× 1 transmitting pre-coding matrix, meets
Figure BSA00000314828000093
symbol
Figure BSA00000314828000094
meet
Figure BSA00000314828000095
The reception signal indication of k Home eNodeB is
y &LeftArrow; k r = &Sigma; i &Element; &kappa; r H &LeftArrow; ki x &LeftArrow; i r + w &LeftArrow; k , &ForAll; k &Element; &kappa; r , r=1,...,R
Wherein,
Figure BSA00000314828000098
n k× M ihome eNodeB i to the channel of subscriber equipment k, and
Figure BSA00000314828000099
Figure BSA000003148280000910
r=1 ..., R,
Figure BSA000003148280000911
it is the white complex gaussian noise of the obedience zero-mean unit variance of Mk × 1.
Receiving terminal does following processing and obtains desired signal
Figure BSA000003148280000912
Wherein,
Figure BSA000003148280000913
m k× 1 receiving terminal processing array.
The flow process that transceiver iteration realizes interference coordination as shown in Figure 3, comprises the steps:
Step 301: downlink transfer initialization: select at random M k× 1 vector v at the tenth of the twelve Earthly Branches kas the transmitting precoding of Home eNodeB k,
Figure BSA000003148280000914
r=1 ..., R;
Step 302: Home eNodeB k sends the training sequence s that length is T i(n), n=1 ..., T;
Step 303: subscriber equipment k covariance to received signal
Figure BSA000003148280000915
carry out maximal possibility estimation,
Obtain
Figure BSA000003148280000916
wherein
Figure BSA000003148280000917
Figure BSA000003148280000918
be n and receive signal.
Then, utilize
Figure BSA000003148280000919
obtain interference and the noise covariance matrix B of subscriber equipment k kestimation
Figure BSA000003148280000920
Step 304: subscriber equipment k utilizes the estimation of interference and noise covariance matrix
Figure BSA000003148280000921
calculate its reception & disposal vector u k,
u k = B k - 1 H kk v k | | B k - 1 H kk v k | | , &ForAll; k &Element; &kappa; r
Step 305: in uplink process, the reception & disposal vector that subscriber equipment k is calculated is directly as its up transmitting precoding,
v &LeftArrow; k = u k , &ForAll; k &Element; &kappa; r
Step 306: and step 302 is similar, subscriber equipment sends training sequence, and Home eNodeB k estimates interference and the noise covariance matrix that it is subject to
Figure BSA00000314828000101
Step 307: Home eNodeB k calculates its reception & disposal vector,
Figure BSA00000314828000102
Figure BSA00000314828000103
Step 308: in a new downlink transmission process, the reception & disposal vector that Home eNodeB k is calculated is directly as its downlink precoding,
Figure BSA00000314828000104
Figure BSA00000314828000105
and return to step 302, carry out next round iteration.
The embodiment of the present invention also proposes a kind of system that realizes Home eNodeB Femtocell interference coordination, and this system comprises Home eNodeB and subscriber equipment,
Described subscriber equipment is used for perception interference strength around, and the interference strength of institute's perception is reported to Home eNodeB; Also estimate to disturb and noise covariance battle array from the training sequence of Home eNodeB for basis, and then calculate pre-coding matrix as uplink precoding battle array, send training sequence according to described uplink precoding paroxysm;
Described Home eNodeB is for carrying out adapted frequency band merge according to the interference strength of user equipment to report, and Home eNodeB is random from ready-portioned frequency range selects a frequency range to carry out transfer of data; Home eNodeB is also estimated to disturb and noise covariance battle array from the training sequence of subscriber equipment for basis, and then calculates precoding battle array as downlink transfer precoding battle array, and send training sequence according to described downlink transfer precoding paroxysm.
Preferably, preset different Signal to Interference plus Noise Ratio threshold value i, the corresponding corresponding frequency range divide value R of each threshold value i, threshold value is higher, the R that it is corresponding iless;
Described Home eNodeB comprises:
Threshold value module, presets different Signal to Interference plus Noise Ratio threshold value for storing i, the corresponding corresponding frequency range divide value R of each threshold value i, threshold value is higher, the R that it is corresponding iless;
Frequency partition module, for by the threshold value of the SINR of user equipment to report and threshold value module stores icompare, if β i< SINR < β i+1, whole bandwidth is divided into R by it isection;
Sending module, for the R from described frequency partition Module Division iin section frequency range, frequency range of random choose is carried out signal transmission.
Preferably, described subscriber equipment comprises:
User's side joint collection of letters covariance estimation module, for covariance to received signal
Figure BSA00000314828000111
carry out maximal possibility estimation, obtain receiving the covariance estimation of signal
Figure BSA00000314828000112
wherein
Figure BSA00000314828000113
Figure BSA00000314828000114
be n and receive signal;
User's side is disturbed and noise covariance estimation module, for utilizing the covariance estimation of the reception signal that described user's side joint collection of letters covariance estimation module obtains
Figure BSA00000314828000115
obtain interference and the noise covariance matrix B of subscriber equipment kestimation
Figure BSA00000314828000116
User's side reception & disposal vector calculation module, for utilizing described user's side is disturbed and noise covariance estimation module obtains interference and the estimation of noise covariance matrix
Figure BSA00000314828000117
calculate its reception & disposal vector u k: u k = B ^ k - 1 H kk v k | | B ^ k - 1 H kk v k | | , &ForAll; k &Element; &kappa; r ;
The reception & disposal vector u that described subscriber equipment calculates described user's side reception & disposal vector calculation module kas its up transmitting precoding,
Figure BSA000003148280001110
Figure BSA000003148280001111
and according to described up transmitting precoding transmitting training sequence.
Preferably, described Home eNodeB comprises:
Base station side is disturbed and noise covariance estimation module, for interference and the noise covariance matrix of estimating that Home eNodeB is subject to
Figure BSA000003148280001112
Base station side reception & disposal vector calculation module, for according to described base station example is disturbed and noise covariance estimation module obtains interference and the estimation of noise covariance matrix
Figure BSA000003148280001113
calculating reception & disposal vector, u &LeftArrow; k = B &LeftArrow; k - 1 H &LeftArrow; kk v &LeftArrow; k | | B &LeftArrow; k - 1 H &LeftArrow; kk v &LeftArrow; k | | , &ForAll; k &Element; &kappa; r ;
The reception & disposal vector that described Home eNodeB calculates described base station side reception & disposal vector calculation module is directly as its downlink precoding,
Figure BSA000003148280001116
Figure BSA000003148280001117
and according to described downlink precoding, the training sequence s that transmission length is T i(n), n=1 ..., T.
Preferably, when Home eNodeB sends training sequence first, select at random M k× 1 vector v at the tenth of the twelve Earthly Branches kas downlink precoding,
Figure BSA00000314828000121
r=1 ..., R i, and according to described downlink precoding, the training sequence s that transmission length is T i(n), n=1 ..., T.
By the up-downgoing transmitting procedure between Home eNodeB in the embodiment of the present invention and subscriber equipment, realize the mechanism that adaptive frequency is divided and distributed interference is aimed at and be summarized as follows:
In downlink transmission process, signal interference ratio SINR can be expressed as
Figure BSA00000314828000122
In uplink process, letter leaks and can be expressed as than SLNR
Figure BSA00000314828000123
Because transceiver effect in up-downgoing transmitting procedure is exchanged,
Figure BSA00000314828000124
Figure BSA00000314828000125
in addition, due to the reciprocity of channel,
Figure BSA00000314828000126
obtain
Figure BSA00000314828000127
so, can find out,
Figure BSA00000314828000128
that is to say, in downlink transmission process, receiving terminal processing array u kto maximize the Multiuser Detection matrix that SINR is target; And in uplink process, order
Figure BSA00000314828000129
Figure BSA000003148280001210
just become to maximize the pre-coding matrix that SLNR is target.Therefore, transmit by up-downgoing, user, in improving SINR, reduces the interference to other users by improving SLNR, by the iteration of limited number of time, can realize victim compression in limited space, aims at thereby realize disturbing.
Fig. 4 is the comparison schematic diagram that the embodiment of the present invention proposes the user data rate cumulative distribution function (CDF) that obtains of disturbance coordination method and the CDF of the user data rate that does not adopt disturbance coordination method to obtain.Consider to have the actual emulation scene of loss through walls, due to the dynamic topological structure of femtocell, consider to have the femtocell (being denoted as NF=2,4,6 in figure) of varying number to disturb Shi center femtocell systematic function around.R represents frequency range number, and the value that does not indicate R represents R=2.Emulation arranges SNR=30dB, and system bandwidth is 6MHz.As can be seen from Figure 4,, in the situation that amount of interference is different, adaptive disturbance is aimed at (in figure, being denoted as AIA) and can be realized than not doing better performance of any interference coordination technique (being denoted as NC in figure).
The foregoing is only preferred embodiment of the present invention, in order to limit the present invention, within the spirit and principles in the present invention not all, any modification of making, be equal to replacement, improvement etc., within all should being included in the scope of protection of the invention.

Claims (4)

1. a disturbance coordination method of Home eNodeB Femtocell, is characterized in that, presets different Signal to Interference plus Noise Ratio threshold value i, the corresponding corresponding frequency range divide value R of each threshold value i, threshold value is higher, the R that it is corresponding iless; Comprise the steps:
A, subscriber equipment perception interference strength around, and the interference strength of institute's perception is reported to Home eNodeB;
B, Home eNodeB carry out adapted frequency band merge according to the interference strength of user equipment to report, and Home eNodeB is random from ready-portioned frequency range selects a frequency range to carry out transfer of data; Described step B comprises:
B1, Home eNodeB be according to the statistic SINR SINR of user equipment to report, and by its SINR and default threshold value icompare, if β i< SINR < β i+1, whole bandwidth is divided into R by it isection;
B2, Home eNodeB are from R iin section frequency range, frequency range of random choose is carried out signal transmission;
C, Home eNodeB send training sequence, and subscriber equipment is estimated to disturb and noise covariance battle array according to the training sequence from Home eNodeB, and then calculates pre-coding matrix as uplink precoding battle array; Described step C comprises:
C1, Home eNodeB k be according to downlink transfer precoding, the training sequence s that to send length be T i(n), n=1 ..., T;
C2, subscriber equipment k covariance to received signal
Figure FDA0000464319290000011
carry out maximal possibility estimation, obtain wherein
Figure FDA0000464319290000013
be n and receive signal;
C3, subscriber equipment k utilize
Figure FDA0000464319290000014
obtain interference and the noise covariance matrix B of subscriber equipment k kestimation
C4, subscriber equipment k utilize the estimation of interference and noise covariance matrix
Figure FDA0000464319290000018
calculate its reception & disposal vector u k:
Figure FDA0000464319290000016
the reception & disposal vector u that subscriber equipment k is calculated kas its uplink precoding,
Figure FDA0000464319290000017
D, subscriber equipment send training sequence, and Home eNodeB k estimates interference and the noise covariance matrix that it is subject to
Figure FDA0000464319290000021
home eNodeB k calculates its reception & disposal vector,
Figure FDA0000464319290000022
the reception & disposal vector that Home eNodeB k is calculated is directly as its downlink transfer precoding,
Figure FDA0000464319290000023
and return to step C.
2. method according to claim 1, is characterized in that, Home eNodeB and subscriber equipment have respectively M kand N kroot antenna, while execution first, step C1 is:
Home eNodeB k selects M at random k× 1 vector v at the tenth of the twelve Earthly Branches kas the downlink transfer precoding of Home eNodeB k,
Figure FDA0000464319290000024
r=1 ..., R i; Home eNodeB k is according to downlink transfer precoding, the training sequence s that to send length be T i(n), n=1 ..., T.
3. a system that realizes Home eNodeB Femtocell interference coordination, is characterized in that, this system comprises Home eNodeB and subscriber equipment,
Described subscriber equipment is used for perception interference strength around, and the interference strength of institute's perception is reported to Home eNodeB; Also estimate to disturb and noise covariance battle array from the training sequence of Home eNodeB for basis, and then calculate pre-coding matrix as uplink precoding battle array, send training sequence according to described uplink precoding paroxysm;
Described Home eNodeB is for carrying out adapted frequency band merge according to the interference strength of user equipment to report, and Home eNodeB is random from ready-portioned frequency range selects a frequency range to carry out transfer of data; Home eNodeB is also estimated to disturb and noise covariance battle array from the training sequence of subscriber equipment for basis, and then calculates precoding battle array as downlink transfer precoding battle array, and send training sequence according to described downlink transfer precoding paroxysm;
Described Home eNodeB comprises:
Threshold value module, presets different Signal to Interference plus Noise Ratio threshold value for storing i, the corresponding corresponding frequency range divide value R of each threshold value i, threshold value is higher, the R that it is corresponding iless;
Frequency partition module, for by the threshold value of the SINR of user equipment to report and threshold value module stores icompare, if β i< SINR < β i+1, whole bandwidth is divided into R by it isection;
Sending module, for the R from described frequency partition Module Division iin section frequency range, frequency range of random choose is carried out signal transmission;
Base station side is disturbed and noise covariance estimation module, for interference and the noise covariance matrix of estimating that Home eNodeB is subject to
Base station side reception & disposal vector calculation module, for according to described base station side is disturbed and noise covariance estimation module obtains interference and the estimation of noise covariance matrix
Figure FDA0000464319290000032
calculating reception & disposal vector,
The reception & disposal vector that described Home eNodeB calculates described base station side reception & disposal vector calculation module is directly as its downlink transfer precoding,
Figure FDA0000464319290000034
and according to described downlink transfer precoding, the training sequence s that transmission length is T i(n), n=1 ..., T;
Described subscriber equipment comprises:
User's side joint collection of letters covariance estimation module, for covariance to received signal
Figure FDA0000464319290000035
carry out maximal possibility estimation, obtain receiving the covariance estimation of signal wherein
Figure FDA0000464319290000037
be n and receive signal;
User's side is disturbed and noise covariance estimation module, for utilizing the covariance estimation of the reception signal that described user's side joint collection of letters covariance estimation module obtains
Figure FDA0000464319290000038
obtain the interference of subscriber equipment and the estimation of noise covariance matrix Bk
Figure FDA0000464319290000039
User's side reception & disposal vector calculation module, for utilizing described user's side is disturbed and noise covariance estimation module obtains interference and the estimation of noise covariance matrix
Figure FDA00004643192900000310
calculate its reception & disposal vector u k:
Figure FDA00004643192900000311
The reception & disposal vector u that described subscriber equipment calculates described user's side reception & disposal vector calculation module kas its uplink precoding,
Figure FDA00004643192900000312
and according to described uplink precoding transmitting training sequence.
4. system according to claim 3, is characterized in that, when Home eNodeB sends training sequence first, selects at random M k× 1 vector v at the tenth of the twelve Earthly Branches kas downlink transfer precoding,
Figure FDA0000464319290000041
r=1 ..., R i, and according to described downlink transfer precoding, the training sequence s that transmission length is T i(n), n=1 ..., T.
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