CN106961297A - A kind of interference alignment schemes distributed based on water injection power - Google Patents
A kind of interference alignment schemes distributed based on water injection power Download PDFInfo
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- CN106961297A CN106961297A CN201710149469.5A CN201710149469A CN106961297A CN 106961297 A CN106961297 A CN 106961297A CN 201710149469 A CN201710149469 A CN 201710149469A CN 106961297 A CN106961297 A CN 106961297A
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/0413—MIMO systems
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/0413—MIMO systems
- H04B7/0426—Power distribution
- H04B7/0434—Power distribution using multiple eigenmodes
- H04B7/0443—Power distribution using multiple eigenmodes utilizing "waterfilling" technique
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
- H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
- H04B7/0413—MIMO systems
- H04B7/0456—Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting
- H04B7/046—Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting taking physical layer constraints into account
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- Mobile Radio Communication Systems (AREA)
Abstract
The invention discloses a kind of interference alignment schemes distributed based on water injection power, base station random broadcast pre-coding matrix first, user is to minimize interference leakage power summation as target, decoding matrix is designed along the direction that transmission rate rises using the gradient descent algorithm based on Grassmann manifold, then communication direction is inverted, the decoding matrix of renewal is sent to base station by user, and base station equally updates pre-coding matrix, convergence is reached after iteration, the final effect for obtaining interference alignment.Then base station is responsible for carrying out power distribution, first each data flow mean allocation power is given according to base station maximum available power set in advance, then according to the channel gain of different data streams, power distribution is iterated to the different data streams for being sent to user using the power distribution mode of water filling.The present invention can be obtained on the premise of complexity is not dramatically increased while reaching interference alignment -- higher transmission rate.
Description
Technical field
The present invention relates to mobile radio telecommunications technical field, particularly a kind of interference alignment side distributed based on water injection power
Method.
Background technology
With the extensive use of multi-antenna technology, interference has become the principal element of limitation wireless network performance lifting.
Traditional disturbance restraining method handle interference is as noise processed or orthogonalization, but these methods have respective weak point,
The method for example handled disturbing as noise is although simple and easy to apply, but can not the larger interference of process signal intensity.
Interference alignment techniques are one of newest interference mitigation technologies, and its basic thought is the interference signal for compressing receiving terminal
The Spatial Dimension of occupancy, ensures that the subspace dimension of desired signal is sufficiently large as far as possible.The appearance of interference alignment techniques changes people
Before the understanding limited by interference of the capacity to wireless network.Because interference alignment techniques have transmission rate high, it is easy to real
The advantages of not limited with power system capacity by number of users now, is one of technology of great potential in next-generation communication network.
Traditional interference alignment can be divided into enclosed resolving Algorithm and distributed iterative interference alignment algorithm, wherein distributed calculate
Method is revealed as target with the interference for minimizing receiving terminal, using the reciprocity of channel, and the interference of alternative optimization transmitting-receiving node is revealed
Power, finally when it is zero to disturb leakage, that is, reaches perfect interference alignment, compared with enclosed resolving Algorithm, it is only necessary to know every
The local channel state information of individual node, and greatly reduce feedback overhead.Also there are many optimized algorithms in distribution
On the basis of iterative algorithm, according to different object functions come design update precoding and decoding matrix, it can reach higher
System velocity.But these algorithms are all to each data flow mean allocation power, in order to more fully utilize the work(of system
Rate, the co-design interference alignment of some scholars proposition in recent years and power distribution algorithm, although what is had can reduce the error code of system
Rate, but to sacrifice a part of transmission rate as cost, what is had then may be only available for certain applications scene, there is certain limitation
Property, some algorithm complexes are higher, it is difficult to be applied in actual engineering.
The content of the invention
The technical problems to be solved by the invention are to overcome the deficiencies in the prior art and provide a kind of based on water injection power point
The interference alignment schemes matched somebody with somebody, the present invention can be obtained on the premise of complexity is not dramatically increased while reaching interference alignment
Higher system transfer rate.
The present invention uses following technical scheme to solve above-mentioned technical problem:
According to a kind of interference alignment schemes distributed based on water injection power proposed by the present invention, comprise the following steps:
Step 1, initialization iterations q=1, initialize step-length t, initialize the pre-coding matrix V of k-th of base stationk,0;
Base station is distributed to the data flow of user by maximum available power averaging;
Step 2, k-th of base station randomly generate M × d dimension pre-coding matrixes Vk,q-1To the user of this cell, and meetWherein, I is unit matrix, and M is antenna for base station number, and d is sent to the data flow of user for base station
Number, subscript H be conjugate transposition, k=1,2,3 ..., K, K be base station total number;
L-th of user that k-th of base station is serviced is according to minimizing when interference leakage criterion calculates the q-1 times iteration the
The decoding matrix U of l userl,q-1,
Wherein, HklRepresent k-th of base station to the channel gain matrix of l-th of user, l=1,2,3 ..., K, channel coefficients
It is zero to obey average, and variance is distributed for 1 independent identically distributed multiple Gauss, Vk,q-1Represent during the q-1 times iteration k-th base station
Pre-coding matrix,The corresponding characteristic vector of d characteristic value minimum representing matrix *, PkFor the power point of k-th of base station
With matrix;
Step 3, by Ul,q-1The direction increased along geodesic curve to transmission rate is moved, and step-length t is used for adjusting Ul,q-1It is mobile away from
From size, obtain the decoding matrix U of l-th of user during the q times iterationl,q;
Step 4, reversion communication direction, k-th of base station calculates the pre-coding matrix V updated during the q times iterationk,q,
Step 5, renewal step-length t=t × 0.90;
Step 6, it is not more than default maximum interference leakage power when the maximum interference leakage power summation that user is subject to, or
When person's iterations has reached maximum iteration, the V now obtainedk,q, Ul,qMake transmission rate performance best respectively
Pre-coding matrixAnd decoding matrixInterference leakage power suffered by user now is zero, that is, has reached interference alignment;
Otherwise q=q+1, repeat step 2 to 5 are made;
Step 7, the power water filling value λ for going out using dichotomizing search k-th of base stationkValue;
Step 8, minimize interference leakage criterion under using maximize useful signal spatial power as target reach interference pair
On the basis of neat, according to the λ of acquisitionk, the power p of the different data streams sent by way of water filling to base stationkjDivided
Match somebody with somebody.
It is used as a kind of further prioritization scheme of interference alignment schemes distributed based on water injection power of the present invention, step
It is 0.90 that step-length t is initialized in 1.
It is used as a kind of further prioritization scheme of interference alignment schemes distributed based on water injection power of the present invention, step
U is obtained in 3l,qDetailed process it is as follows:
First obtain the power in useful signal spaceIt is right
Ul,q-1Derivative QklUl,q-1, wherein,Then ladders of the P along Grassmann manifold is obtained
Degree descent direction is Zk,And to ZkCarry out Eigenvalues Decomposition and obtain G Σ FH, its
Middle G, F are unitary matrice, and Σ is diagonal matrix;
The decoding matrix then updated is Ul,q=(Ul,q-1F(cosΣt)FH)+(G(sinΣt)FH)。
It is used as a kind of further prioritization scheme of interference alignment schemes distributed based on water injection power of the present invention, step
Maximum iteration is 5000 times in 6, and default maximum interference leakage power is 10-6Watt.
It is used as a kind of further prioritization scheme of interference alignment schemes distributed based on water injection power of the present invention, step
The power p of each data flow in 8kjObtained from below equation:
Wherein, parameter tkjRepresent interference of j-th of the data flow of k-th of base station to other data flows, IljIt is l-th of use
Summation, σ are disturbed between inter-user interference and data flow that family is subject to2For the variance of multiple Gauss noise,For k-th base station
J-th of data flows to the efficient channel gain of j-th of data flow of l-th of user, (*)+=max (*, 0),The jth row of subscript [* j] representing matrix.
The present invention uses above technical scheme compared with prior art, with following technique effect:
(1) interference alignment and power distributing technique are combined, is designed first by maximizing with speed interference alignment schemes
Pre-coding matrix and decoding matrix, i.e., move matrix along the direction that transmission rate increases, and is reached in base station and user terminal dry
Disturb after alignment, the performance of further lifting system is combined with water injection power distribution method, due to the power distribution algorithm not only
Consider the interference between user, it is also contemplated that the interference between data flow, therefore base station can be with to the transmission rate performance of user
Obtain good lifting;
(2) to maximize power as object function, using the gradient descent algorithm based on Grassmann manifold along transmission
The direction design decoding matrix that speed rises, can simplify derivative operation, reduce complexity;The method of the invention is applied to
Wireless data transmission scene in MIMO interference channels.
Brief description of the drawings
Fig. 1 is the equivalent interference channel figure of the applicable K cell K custom systems of the present invention.
Fig. 2 is the equivalent scene graph for the user of 3 cell 3 that present example is applicable.
Fig. 3 is flow chart of the invention.
Fig. 4 is the comparison figure of the invention with the system average transmission rate performance of traditional minimum interference leakage method.
Embodiment
Technical scheme is described in further detail below in conjunction with the accompanying drawings:
Fig. 1 is the equivalent interference channel figure of the applicable K cell K custom systems of the present invention, and present case uses 3 cells, often
Individual one user of cell serves, base station and user are equipped with the downlink scenario of 5 antennas, and each base station is sent to user 2
Individual data flow.System works in the downlink.Each base station can produce interference, especially minizone to the user of non-cell
Edge customer can be by larger interference, system model as shown in Fig. 2 flow is as shown in figure 3, specific implementation steps are:
(1) iterations q=1, is initialized, initialization step-length t, k-th of Base station initialization 5 × 2 ties up pre-coding matrix
Vk,0, k=1,2,3, maximum available transmission power is averagely allocated to the data flow of user by base station.
(2) k-th of the dimension pre-coding matrix of Base Transmitter 5 × 2 Vk,q-1To the user of this cell, and meetWherein, I is unit matrix, k=1,2,3.
L-th of user that k-th of base station is serviced designs decoding matrix U according to interference leakage criterion is minimizedl,q-1,
Wherein, HklK-th of base station is represented to the channel gain matrix of l-th of user, it is zero that channel coefficients, which obey average, side
Difference is distributed for 1 independent identically distributed multiple Gauss, Vk,q-1The pre-coding matrix of k-th of base station during the q-1 times iteration is represented,The corresponding characteristic vector of d characteristic value minimum representing matrix *, PkFor the power distribution matrix of k-th of base station, k=1,
2,3。
(3) power in useful signal space is first obtained
To Ul,q-1Derivative QklUl,q-1, wherein,HklRepresent k-th of base station to l-th of use
The channel gain matrix at family, Vk,q-1The pre-coding matrix of k-th of base station, U during for the q-1 times iterationl,q-1It is the q-1 times iteration
When l-th of user decoding matrix, PkFor the power distribution matrix of k-th of base station;Then ladders of the P along Grassmann manifold is obtained
Degree descent direction is Zk,And to ZkCarry out Eigenvalues Decomposition and obtain G Σ FH, its
Middle G, F are unitary matrice, and Σ is diagonal matrix;
The decoding matrix then updated is Ul,q=(Ul,q-1F(cos Σt)FH)+(G(sinΣt)FH), l=1,2,3.
By the decoding matrix U of l-th of user during the q times iterationl,q-1The direction increased along geodesic curve to transmission rate is moved,
Step-length t is used for adjusting the size of matrix displacement, can obtain the decoding matrix of the renewal of l-th of user during the q times iteration
Ul,q。
(4) communication direction is inverted, k-th of base station calculates the pre-coding matrix updated when obtaining the q times iteration
(5) step-length t=t × 0.90 is updated.
(6) when the maximum interference leakage power summation that user is subject to is not more than default leakage power, or reach
During maximum iteration, V nowk,q, Ul,qIt is the pre-coding matrix for making transmission rate performance best respectivelyWith decoding square
Battle arrayInterference leakage power suffered by user now is zero, that is, has reached interference alignment;Otherwise q=q+1, repeat step are made
2 to 5.
(7) the power water filling value λ of k-th of base station is gone out using dichotomizing searchkValue, λkValue from below equation
Obtain:
Wherein, PktIt is P for the maximum available power of k-th of base stationkt, σ2For the variance of multiple Gauss noise, parameter tkjRepresent
Interference of j-th of the data flow of k-th of base station to other data flows, IljIt is inter-user interference and data that l-th of user is subject to
Summation is disturbed between stream.pkiFor the power of i-th of data flow distribution of k-th of base station, pniFor i-th of data of nth base station
The power of distribution is flowed,The efficient channel for j-th of data flow for flowing to l-th of user for i-th of data of nth base station increases
Benefit,For k-th of base station i-th of data flow to l-th of user j-th of data flow efficient channel gain,For m
F-th of data of individual base station flow to the efficient channel gain of i-th of data flow of l-th of user,For the i-th of k-th of base station
Individual data flow to the efficient channel gain of i-th of data flow of l-th of user,J-th of data for k-th of base station are flowed to
The efficient channel gain of j-th of data flow of l-th of user.
(8) minimize interference leakage criterion under using maximize useful signal spatial power as target reach interference alignment
On the basis of, according to the λ of acquisitionk, the power p of the different data streams sent by way of water filling to base stationkjDivided successively
Match somebody with somebody.
Wherein, (*)+=max (*, 0), J-th of data for k-th of base station are flowed to
The efficient channel gain of j-th of data flow of l-th of user, the jth row of subscript [* j] representing matrix.
In order to evaluate the performance of the present invention, the average transmission rate performance of system is done using the method for Monte Carlo simulation
Emulation.It is zero that channel matrix, which obeys average, and variance is distributed for 1 Cyclic Symmetry multiple Gauss, initializes pre-coding matrix, initially
Change power distribution matrix and step-length sets all same, maximum iteration is 5000 steps, takes the average value of 100 simulation results.
Fig. 4 is compared the interference alignment algorithm distributed based on water injection power and the least interference that constant power is distributed and reveals algorithm
Average and speed with signal to noise ratio variation relation.As can be seen that based on water injection power control interference alignment schemes performance compared with
The former averagely obtains 10.3bps/Hz rate gain.
It should be appreciated that for those of ordinary skills, can according to the above description be improved or converted,
And all these modifications and variations should all belong to the protection domain of appended claims of the present invention.
Claims (5)
1. a kind of interference alignment schemes distributed based on water injection power, it is characterised in that comprise the following steps:
Step 1, initialization iterations q=1, initialize step-length t, initialize the pre-coding matrix V of k-th of base stationk,0;Base station
Maximum available power averaging is distributed to the data flow of user;
Step 2, k-th of base station randomly generate M × d dimension pre-coding matrixes Vk,q-1To the user of this cell, and meetWherein, I is unit matrix, and M is antenna for base station number, and d is sent to the data flow of user for base station
Number, subscript H be conjugate transposition, k=1,2,3 ..., K, K be base station total number;
L-th of user that k-th of base station is serviced is revealed when criterion calculates the q-1 times iteration l-th according to interference is minimized
The decoding matrix U of userl,q-1,
Wherein, HklRepresent k-th of base station to the channel gain matrix of l-th of user, l=1,2,3 ..., K, channel coefficients obedience
Average is zero, and variance is distributed for 1 independent identically distributed multiple Gauss, Vk,q-1Represent during the q-1 times iteration prelisting for k-th base station
Code matrix,The corresponding characteristic vector of d characteristic value minimum representing matrix *, PkFor the power distribution square of k-th of base station
Battle array;
Step 3, by Ul,q-1The direction increased along geodesic curve to transmission rate is moved, and step-length t is used for adjusting Ul,q-1Displacement
Size, obtains the decoding matrix U of l-th of user during the q times iterationl,q;
Step 4, reversion communication direction, k-th of base station calculates the pre-coding matrix V updated during the q times iterationk,q,
Step 5, renewal step-length t=t × 0.90;
Step 6, it is not more than default maximum interference leakage power when the maximum interference leakage power summation that user is subject to, or repeatedly
When generation number has reached maximum iteration, the V now obtainedk,q, Ul,qIt is prelisting of making transmission rate performance best respectively
Code matrixAnd decoding matrixInterference leakage power suffered by user now is zero, that is, has reached interference alignment;Otherwise
Make q=q+1, repeat step 2 to 5;
Step 7, the power water filling value λ for going out using dichotomizing search k-th of base stationkValue;
Step 8, minimize interference leakage criterion under using maximize useful signal spatial power as target reach interference alignment
On the basis of, according to the λ of acquisitionk, the power p of the different data streams sent by way of water filling to base stationkjIt is allocated.
2. a kind of interference alignment schemes distributed based on water injection power according to claim 1, it is characterised in that step 1
Middle initialization step-length t is 0.90.
3. a kind of interference alignment schemes distributed based on water injection power according to claim 1, it is characterised in that step 3
In obtain Ul,qDetailed process it is as follows:
First obtain the power in useful signal spaceTo Ul,q-1's
Derivative QklUl,q-1, wherein,Then gradients of the P along Grassmann manifold is obtained to decline
Direction is Zk,And to ZkCarry out Eigenvalues Decomposition and obtain G Σ FH, wherein G, F is equal
For unitary matrice, Σ is diagonal matrix;
The decoding matrix then updated is Ul,q=(Ul,q-1F(cosΣt)FH)+(G(sinΣt)FH)。
4. a kind of interference alignment schemes distributed based on water injection power according to claim 1, it is characterised in that step 6
Middle maximum iteration is 5000 times, and default maximum interference leakage power is 10-6Watt.
5. a kind of interference alignment schemes distributed based on water injection power according to claim 1, it is characterised in that step 8
In each data flow power pkjObtained from below equation:
Wherein, parameter tkjRepresent interference of j-th of the data flow of k-th of base station to other data flows, IljL-th of user by
Inter-user interference and data flow between disturb summation, σ2For the variance of multiple Gauss noise,For j-th of number of k-th of base station
According to the efficient channel gain for j-th of data flow for flowing to l-th of user, (*)+=max (*, 0),
The jth row of subscript [* j] representing matrix.
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CN111342869A (en) * | 2020-02-10 | 2020-06-26 | 郑州轻工业大学 | Interference alignment design method and system based on off-diagonal channel |
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IGNACIO SANTAMARIA ET AL: "Maximum Sum-Rate Interference Alignment Algorithms for MIMO Channels", 《2010 IEEE GLOBAL TELECOMMUNICATIONS CONFERENCE》 * |
MIN LEE AND SEONG KEUN OH: "A Simplified Iterative Water-Filling Algorithm for Per-User Power Allocation in Multiuser MMSE-Precoded MIMO Systems", 《VTC SPRING 2008》 * |
ZHENGYU ZHU ET AL: "Maximum power interference alignment scheme for less computational cost in MIMO interference channel", 《2013 IEEE/CIC INTERNATIONAL CONFERENCE ON COMMUNICATIONS IN CHINA (ICCC)》 * |
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CN111342869A (en) * | 2020-02-10 | 2020-06-26 | 郑州轻工业大学 | Interference alignment design method and system based on off-diagonal channel |
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