CN107911867A - A downlink transmission and interference coordination method for a cellular and D2D hybrid communication network - Google Patents

Abstract

The invention discloses the downlink transfer and disturbance coordination method of a kind of honeycomb and D2D hybrid communication networks, the D2D communications pair in hybrid network in cellular basestation coverage there are some shared down frequency spectrum resources, cellular basestation uses uniform planar antenna array；Cellular basestation using the first service of dispatching out of known statistic channel information phone user and calculate its precoding vector, the interference from D2D communications pair is coordinated to the phone user dispatched out again, then the interference between D2D communications pair is coordinated, then communicate using known statistic channel information and certain customers' equivalent channels information to D2D comes from cellular interference to coordination；After interference coordination, cellular basestation only carries out precoding transmissions to remaining user in its service user set.The present invention has the advantages of required channel information amount is small, and computation complexity is low, can flexibly set different thresholdings to meet different QoS of customer, effectively reduces and is disturbed between honeycomb and D2D hybrid communication networks.

Description

A downlink transmission and interference coordination method for a cellular and D2D hybrid communication network

technical field

The invention relates to the technical field of downlink transmission and interference coordination, in particular to a method for downlink transmission and interference coordination of a cellular and D2D hybrid communication network.

Background technique

With the rapid development of wireless communication technology and the rapid increase in the number of various types of intelligent mobile terminals, higher requirements are placed on the transmission rate and user experience of wireless communication systems. As one of the solutions to improve the overall network, device-to-device (D2D) communication meets the requirement of direct communication between wireless devices. The method aims to enable user communication equipment within a certain distance to communicate directly, so as to reduce the load on the serving base station. It allows user equipment to directly communicate with nearby users through a device-to-device communication link by utilizing cellular network resources without going through a base station. Compared with other direct technologies that do not rely on basic network facilities, D2D is more flexible. It can not only perform connection and resource allocation under the control of the base station, but also perform information interaction when there is no network infrastructure. Deploying massive MIMO (multiple-input multiple-output) with hundreds or even thousands of antennas in base stations is another effective method to improve network transmission rate and coverage. Compared with the existing MIMO, the spatial resolution of massive MIMO is significantly enhanced, and it can deeply mine spatial dimension resources, so that multiple users in the network can use the spatial freedom provided by massive MIMO on the same time-frequency resource to conduct simultaneous communication with the base station. Communication, thereby greatly improving spectral efficiency without increasing bandwidth. In addition, massive MIMO can greatly reduce the transmission power, and realize green communication through low-cost and low-power devices.

Massive MIMO and hybrid networks equipped with D2D can greatly improve the spectral efficiency and power efficiency of wireless communication, and are considered to be the key technologies for building future high-performance green mobile communication systems. However, in practical applications, massive MIMO wireless communication faces many challenges, one of which is that the number of antennas that can be configured by the base station is affected by the space of the base station and the carrier frequency. In order to overcome the limitations of limited space on massive MIMO wireless communication systems and further tap and utilize vertical space resources, in recent years people have proposed a large-scale antenna array arranged in a two-dimensional grid at the base station, called 3D-MIMO. The acquisition of channel information is another challenge faced by massive MIMO. Most of the existing massive MIMO transmission schemes use uplink orthogonal pilots and TDD system uplink and downlink channel reciprocity. The base station obtains multi-user uplink and downlink channel parameter estimates, and implements uplink reception processing and downlink precoding transmission. . However, this solution is difficult to adapt to medium and high-speed mobile communication scenarios and FDD systems. The statistical state information of the channel is approximately unchanged for a considerable period of time, and its accuracy is relatively high. The transmission scheme using statistical channel state information has the advantages of simple implementation, small feedback, strong robustness, and can be applied to both TDD and The advantage of the FDD system is that it is an effective method to overcome the problem of channel information acquisition. In addition, while the introduction of D2D obtains transmission rate gain, it also brings about the problem of inter-user interference in a hybrid network.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a downlink transmission and interference coordination method for a cellular and D2D hybrid communication network. To reduce the power of the device communication or set it to a dormant state, perform zero-forcing precoding on macro-cell users with large interference, reduce inter-layer interference and increase the rate of edge users with relatively low complexity.

The present invention adopts the following technical solutions for solving the problems of the technologies described above:

A downlink transmission and interference coordination method for a cellular and D2D hybrid communication network proposed according to the present invention includes the following steps:

Step 1. There are several D2D communication pairs sharing downlink spectrum resources with the cellular base station in the hybrid network. The cellular base station adopts a uniform planar antenna array, including M _v rows of antenna elements in the vertical direction, and each row of M _h array elements in the horizontal direction , the total transmission power is P _c ; the number of cellular users in the hybrid network is L, and the kth cellular user is denoted as CUE _k ; the i-th D2D communication pair includes the transmitting end TUE _i and the receiving end RUE _i , both of which are equipped with a single antenna, its transmit power up to minimum is Wherein, i=1,...,N _s , N _s is the number of D2D communication pairs in the hybrid network;

First, the transmit power of each D2D communication pair Initialize to maximum transmit power Set of D2D communication pairs with communication closed and cellular base station service user set initialized to an empty set;

Step 2, using the known statistical channel information to calculate the key parameters of each D2D communication pair and cellular user;

Step 3: Carry out cellular base station service user scheduling and calculate the scheduled service user set Each cellular user precoding vector in ;

Step 4. Coordinate the interference to cellular users for each D2D communication pair one by one;

Step five, coordinating interference between D2D communication pairs one by one;

Step 6, coordinating the interference from the cell for D2D communication pairs one by one;

Step 7. After the interference coordination is completed, only the set The remaining cellular users in the precoded transmission will be aggregated The communication between the D2D communication pairs in is closed.

As a further optimization scheme of the downlink transmission and interference coordination method of a cellular and D2D hybrid communication network described in the present invention, the statistical channel information in step 2 includes:

Large-scale fading factor of the channel between a cellular base station and the kth cellular user Among them, k=1,...,L, the vertical transmission correlation matrix of the kth cellular user and horizontally send correlation array Among them, the matrix H _c,k is the normalized channel matrix between the cellular base station and the kth cellular user, satisfying The element [H _c,k ] _{m,n in row m and column n} is the channel coefficient between the antenna array element in row m and column n of the cellular base station and the kth cellular user, and the superscript ( ) ^H stands for Conjugate transpose, E{ } represents the average value, tr{ _} represents the trace of the matrix _; the large scale fading factor and the large-scale fading factor of the channel between the cell base station and RUE _i Vertical Transmit Correlator and horizontally send correlation array Among them, the matrix is the normalized channel matrix between the cell base station and RUE _i , satisfying The element in the mth row and the nth column is the channel coefficient between the antenna element in row m and column n of the cellular base station and RUE _i ; the large-scale fading factor of the channel between TUE _i and the kth cellular user

As a further optimization scheme of the downlink transmission and interference coordination method of a cellular and D2D hybrid communication network described in the present invention, in step 2, the cellular base station uses the statistical channel information to calculate the key parameters of each D2D communication pair and cellular user including:

1) For the kth cellular user, calculate and in, and are the DFT matrices of M _v ×M _v and M _h ×M _h respectively, and the elements of the mth row and the nth column are respectively and e is the natural base, and j' is the imaginary unit;

2) For the kth cellular user, calculate and in, and are respectively the a-th diagonal element of Λ _{V, c, k} and the b-th diagonal element of Λ _{H, c, k} , and let as well as

3) For RUE _i , calculate and

As a further optimization scheme of the downlink transmission and interference coordination method of a cellular and D2D hybrid communication network described in the present invention, step 3 is specifically as follows:

1.1) Select N'+1 integers and M′+1 integers Satisfy as well as Wherein N' is a positive integer less than M _h , and M' is a positive integer less than M _v ;

1.2) Divide all L cellular users into M'N' groups, and the division criterion is: if the kth cellular user satisfies and put it in the group

1.3) From each group of cellular users select their and The cellular user whose product is the largest, the total number of selected cellular users is denoted as

1.4) If Where K is the maximum number of users served by the cellular base station at the same time, then the cellular users selected in step 1.3) are added to the cellular base station service user set Otherwise, the selected from step 1.3) Among the cellular users, select the and The K cellular users with the largest product will be added to the service user set of the cellular base station Collection of Cellular Service Users The number of cellular users is denoted as K _c ;

1.5) pair set Each cellular user in calculates its beamforming vector, let the set The lth cellular user in is Its beamforming vector The calculation method is where l=1,...,K _c , stands for Kroneck product operation, superscript ( ) ^* stands for conjugate, for the matrix First List, for the matrix First List.

As a further optimization scheme of the downlink transmission and interference coordination method of a cellular and D2D hybrid communication network described in the present invention, the details of coordinating the interference of the i-th D2D communication pair to cellular users in the step 4 are as follows:

2.1) If the i-th D2D communication pair does not belong to Then let l=1 and enter step 2.2); otherwise, end the interference coordination of the D2D communication pair to the cellular user;

2.2) Calculate the i-th D2D communication pair set The lth cellular user in Interference measure of

2.3) If is less than or equal to a preset threshold value δ ₁ , go to step 2.7); otherwise, go to step 2.4);

2.4) The transmission power of the i-th D2D communication pair reduced to be able to satisfy the i-th D2D communication pair-to-cellular user Interference measure of The maximum value less than or equal to the threshold value δ ₁

2.5) If P _di is greater than or equal to the minimum transmit power of the D2D communication pair Go to step 2.7); otherwise, go to step 2.6);

2.6) Close the communication of the i-th D2D communication pair, that is, add it to the set And end the interference coordination of the i-th D2D communication pair to the cellular user;

2.7) Let l=l+1; if l≤K _c , go to step 2.2), otherwise end the interference coordination of the i-th D2D communication pair to the cellular user.

As a further optimization scheme of the downlink transmission and interference coordination method of a cellular and D2D hybrid communication network described in the present invention, the details of coordinating the interference between D2D communication pairs for the i-th D2D communication pair in step 5 are as follows:

3.1) If the i-th D2D communication pair does not belong to Then set j=1 and enter step 3.2); otherwise, end the D2D communication inter-pair interference coordination of the D2D communication pair;

3.2) If j≠i, enter step 3.3); otherwise, enter step 3.6);

3.3) If the jth D2D communication pair does not belong to Then use the following formula to calculate its interference metric value for the i-th D2D communication pair

And go to step 3.4), where is the large-scale fading factor between the transmitter TUE _j of the j-th D2D communication pair and the receiver RUE _i of the i-th D2D communication pair, is the large-scale fading factor between the transmitting end TUE _i and the receiving end RUE _i of the i-th D2D communication pair; otherwise, go to step 3.6);

3.4) If is less than or equal to a certain preset threshold value δ _{2 )} , then go to step 3.6); otherwise, go to step 3.5);

3.5) Comparing large-scale fading factors and in is the large-scale fading factor between the sending end TUE _j and the receiving end RUE _j of the jth D2D communication pair; if Then close the communication of the jth D2D communication pair, that is, add it to the set And enter step 3.6); otherwise, close the communication of the i-th D2D communication pair, that is, add it to the set And end the D2D communication inter-pair interference coordination of the i-th D2D communication pair;

3.6) Set j=j+1; if j≤N _s , go to step 3.2), otherwise end the D2D communication inter-pair interference coordination of the i-th D2D communication pair.

As a further optimization scheme of the downlink transmission and interference coordination method of a cellular and D2D hybrid communication network described in the present invention, in the step 6, coordinate the interference from the cellular for the i-th D2D communication pair in the following steps:

4.1) If the i-th D2D communication pair does not belong to Then enter step 4.2); otherwise, end the D2D communication interference coordination from the cell;

4.2) Calculation set The interference measurement value of each cellular user to the i-th D2D communication pair in , let the set The lth cellular user in is but The interference metric value of the i-th D2D communication pair is denoted as

4.3) Find the set Among them, the cellular user with the largest interference measure value for the i-th D2D communication pair is set to the p _i- th cellular user like Interference measure for the i-th D2D communication pair is less than or equal to a preset threshold value δ ₃ , then end the D2D communication interference coordination from the macro cell; otherwise, go to step 4.4);

4.4) Calculation and in and respectively The a-th diagonal element of and The bth diagonal element of , and are respectively the vertical transmission correlation matrix and the horizontal transmission correlation matrix of the p _i cellular user, the matrix is the normalized channel matrix between the cellular base station and the p _ith cellular user,

4.5) Calculation in vec( ) stands for matrix straightening operation, superscript T is transpose;

4.6) Calculation

4.7) Recalculate the p _ith cellular user The beamforming vector of make Wherein, q ₁ is the first column of Q; end the interference coordination of the D2D communication to the cell.

As a further optimization scheme of the downlink transmission and interference coordination method of a cellular and D2D hybrid communication network described in the present invention, the interference measurement value of the i-th D2D communication pair to the k- _th cellular user in step 2.2) The calculation method is:

And step 2.4) satisfies The maximum transmit power less than or equal to the threshold value δ ₁ for

in is the large-scale fading factor of the channel between the cellular base station and the k _lth cellular user, is the large-scale fading factor of the channel between TUE _i and the k _lth cellular user, and respectively First diagonal elements and First diagonal elements, and are the vertical transmission correlation matrix and the horizontal transmission correlation matrix of the k _lth cellular user respectively, the matrix is the normalized channel matrix between the cellular base station and the k _lth cellular user, and respectively The a-th diagonal element of and The bth diagonal element of .

As a further optimization scheme of the downlink transmission and interference coordination method of a cellular and D2D hybrid communication network described in the present invention, set in step 4.2) The lth macro cell user in Interference measure for the i-th D2D communication pair The calculation method is:

in and are respectively Λ _{H, d, i} 's diagonal elements and Λ _V,d,i'th Diagonal elements.

Compared with the prior art, the present invention adopts the above technical scheme and has the following technical effects:

(1) This method mainly uses the statistical information of the channel, and the amount of required channel information is small, and is applicable to various typical wireless communication systems;

(2) The inter-user interference measurement in the method has low computational complexity and is easy to implement;

(3) This method can flexibly set different thresholds according to the requirements of system and user service quality, so as to satisfy different user service quality and system throughput.

Detailed ways

The technical scheme of the present invention is described in further detail below:

Method of the present invention mainly comprises the following steps:

Step 1. There are several D2D communication pairs sharing downlink spectrum resources with the cellular base station in the hybrid network. The cellular base station adopts a uniform planar antenna array, including M _v rows of antenna elements in the vertical direction, and each row of M _h array elements in the horizontal direction , the total transmission power is P _c ; the number of cellular users in the hybrid network is L, and the kth cellular user is denoted as CUE _k ; the i-th D2D communication pair includes the transmitting end TUE _i and the receiving end RUE _i , both of which are equipped with a single antenna, its transmit power up to minimum is Among them, i=1,...,N _s , N _s is the number of D2D communication pairs in the hybrid network; the transmission power of each D2D communication pair is initialized to the maximum transmission power Set of D2D communication pairs with communication closed and macro cell base station service user set initialized to an empty set;

Step 2. Calculate the key parameters of each D2D communication pair and cellular user by using the known statistical channel information. The known statistical channel information includes: the large-scale fading factor of the channel between the cellular base station and the kth cellular user Where k=1,...,L; the vertical transmission correlation matrix of the kth cellular user and horizontally send correlation array Among them, the matrix H _c,k is the normalized channel matrix between the cellular base station and the kth cellular user, satisfying The element [H _c,k ] _{m,n in row m and column n} is the channel coefficient between the antenna array element in row m and column n of the cellular base station and the kth cellular user k, superscript (·) ^H represents the conjugate transpose, E{· _} represents the average value, tr{·} represents the trace of the _matrix ; large-scale fading factor and the large-scale fading factor of the channel between the cell base station and RUE _i Vertical Transmit Correlator and horizontally send correlation array matrix is the normalized channel matrix between the cell base station and RUE _i , satisfying The element in the mth row and the nth column is the channel coefficient between the antenna element in row m and column n of the cellular base station and RUE _i ; the large-scale fading factor of the channel between TUE _i and the kth cellular user The key parameters calculated include:

1) For the kth cellular user CUE _k , k=1,...,L, calculate and in and are the DFT matrices of M _v ×M _v and M _h ×M _h respectively, and the elements of the mth row and the nth column are respectively and e is the natural base, and j' is the imaginary unit;

2) For the kth cellular user CUE _k , k=1,...,L, calculate and in and are respectively the a-th diagonal element of Λ _{V, c, k} and the b-th diagonal element of Λ _{H, c, k} , and let as well as

3) For RUE _i , i=1,...,N _s , calculate and

Step 3: Carry out cellular base station service user scheduling and calculate the scheduled service user set according to the following steps Each cellular user precoding vector in:

1.1) Select N'+1 integers and M′+1 integers Satisfy as well as Wherein N' is a positive integer less than M _h , and M' is a positive integer less than M _v ;

1.2) Divide all L cellular users into M'N' groups, and the division criterion is: if the kth cellular user satisfies and put it in the group in,

1.3) From each group of cellular users select their and The cellular user whose product is the largest, the number of selected cellular users is denoted as

1.4) If Where K is the maximum number of users served by the cellular base station at the same time, then the cellular users selected in step 1.3) are added to the cellular base station service user set Otherwise, the selected from step 1.3) Among the cellular users, select the and The K cellular users with the largest product will be added to the service user set of the cellular base station Collection of Cellular Service Users The number of cellular users is denoted as K _c ;

1.5) pair set Beamforming vectors for each cellular user computer in , assuming the set The lth cellular user in is Its beamforming vector The calculation method is where l=1,...,K _c , stands for Kroneck product operation, superscript ( ) ^* stands for conjugate, for the matrix First List, for the matrix First List;

Step 4: For each D2D communication pair, coordinate its interference to the cellular user one by one, and coordinate the interference to the cellular user for the i-th D2D communication pair as follows:

2.1) If the i-th D2D communication pair does not belong to Then let l=1 and enter step 2.2); otherwise, end the interference coordination of the D2D communication pair to the cellular user;

2.2) Calculate the i-th D2D communication pair set The lth cellular user in , assuming Interference measure of

in is the large-scale fading factor of the channel between the cellular base station and the k _lth cellular user, is the large-scale fading factor of the channel between TUE _i and the k _lth cellular user, and respectively First diagonal elements and First diagonal elements, and are the vertical transmission correlation matrix and the horizontal transmission correlation matrix of the k _lth cellular user respectively, the matrix is the normalized channel matrix between the cellular base station and the k _lth cellular user, and respectively The a-th diagonal element of and The bth diagonal element of ;

2.3) If is less than or equal to a preset threshold value δ ₁ , go to step 2.7); otherwise, go to step 2.4);

2.4) The transmission power of the i-th D2D communication pair reduced to be able to satisfy the i-th D2D communication pair-to-cellular user Interference measure of The maximum value less than or equal to the threshold value δ ₁ in, for

2.5) If Greater than or equal to the minimum transmit power of the D2D communication pair Go to step 2.7); otherwise, go to step 2.6);

2.6) Close the communication of the i-th D2D communication pair, that is, add it to the set And end the interference coordination of the i-th D2D communication pair to the cellular user;

2.7) Let l=l+1; if _l≤Kc , go to step 2.2), otherwise end the interference coordination of the i-th D2D communication pair to the cellular user;

Step 5: Coordinate the interference between the D2D communication pairs one by one, and coordinate the interference between the D2D communication pairs for the i-th D2D communication pair as follows:

3.1) If the i-th D2D communication pair does not belong to Then set j=1 and enter step 3.2); otherwise, end the D2D communication inter-pair interference coordination of the D2D communication pair;

3.2) If j≠i, enter step 3.3); otherwise, enter step 3.6);

3.3) If the jth D2D communication pair does not belong to Then use the following formula to calculate its interference metric value for the i-th D2D communication pair

And go to step 3.4), where is the large-scale fading factor between the transmitter TUE _j of the j-th D2D communication pair and the receiver RUE _i of the i-th D2D communication pair, is the large-scale fading factor between the transmitter TUE _i and the receiver RUE _i of the i-th D2D communication pair; otherwise, go to step 3.6)

3.4) If is less than or equal to a certain preset threshold value δ _{2 )} , then go to step 3.6); otherwise, go to step 3.5);

3.5) Comparing large-scale fading factors and in is the large-scale fading factor between the sending end TUE _j and the receiving end RUE _j of the jth D2D communication pair; if Then close the communication of the jth D2D communication pair, that is, add it to the set And enter step 3.6); otherwise, close the communication of the i-th D2D communication pair, that is, add it to the set And end the D2D communication inter-pair interference coordination of the i-th D2D communication pair;

3.6) Let j=j+1; if j≤N _s , go to step 3.2), otherwise end the D2D communication inter-pair interference coordination of the i-th D2D communication pair;

Step 6: Coordinating the interference from the cell for the D2D communication pair one by one, wherein the coordination of the interference from the cell for the i-th D2D communication pair is performed as follows;

4.1) If the i-th D2D communication pair does not belong to Then enter step 4.2); otherwise, end the D2D communication interference coordination from the cell;

4.2) Calculation set The interference metric value of each cellular user to the i-th D2D communication pair in , assuming the set The lth cellular user in is but The interference metric value of the i-th D2D communication pair is denoted as Its calculation method is:

in and are respectively Λ _{H, d, i} 's diagonal elements and Λ _V,d,i'th diagonal elements;

4.3) Find the set The cellular user with the largest interference metric value for the i-th D2D communication pair is assumed to be the p- _th cellular user like Interference measure for the i-th D2D communication pair is less than or equal to a preset threshold value δ ₃ , then end the interference coordination of the D2D communication to the cell; otherwise, go to step 4.4);

4.4) Calculation and in and respectively The a-th diagonal element of and The bth diagonal element of , and are respectively the vertical transmission correlation matrix and the horizontal transmission correlation matrix of the p _i cellular user, the matrix is the normalized channel matrix between the cellular base station and the p _ith cellular user,

4.5) Calculation in vec( ) stands for matrix straightening operation, superscript T is transpose;

4.6) Calculation

4.7) Recalculate the p _ith cellular user The beamforming vector of make Wherein, q ₁ is the first column of Q; end the interference coordination of the D2D communication to the cell.

Step 7. After the interference coordination is completed, only the set The remaining cellular users in the precoded transmission will be aggregated The communication between the D2D communication pairs in is closed.

In order to make the technical solution among the present invention clearer, this solution is described in detail below:

Consider a cellular and D2D hybrid communication network. In the hybrid network, there are several D2D communication pairs sharing downlink spectrum resources with the cellular base station coverage area. The cellular base station adopts a uniform planar antenna array, including M _v rows of antenna elements in the vertical direction and horizontal direction There are M _h array elements in each row, and the total transmission power is P _c ; the number of cellular users in the hybrid network is L, and the kth cellular user is denoted as CUE _k ; the i-th D2D communication pair includes the transmitting end TUE _i and the receiving end RUE _i , are equipped with a single antenna, and its transmit power up to minimum is Where i=1,...,N _s , N _s is the number of D2D communication pairs in the hybrid network; firstly, the transmission power of each D2D communication pair is initialized to the maximum transmission power Set of D2D communication pairs with communication closed and cellular base station service user set Initialize as an empty set; then use the known statistical channel information to calculate the key parameters of each D2D communication pair and cellular user; then perform cellular base station service user scheduling and calculate the scheduled service user set The precoding vectors of each cellular user; then firstly coordinate the interference to the cellular users for each D2D communication pair one by one, then coordinate the interference between the D2D communication pairs one by one, and finally coordinate the interference from the cell for each D2D communication pair one by one; the interference After reconciliation, only for collection The remaining cellular users in the precoded transmission will be aggregated The communication between the D2D communication pairs in is closed.

The statistical channel information includes:

Large-scale fading factor of the channel between a cellular base station and the kth cellular user Among them, k=1,...,L,; the vertical transmission correlation matrix of the kth cellular user and horizontally send correlation array Among them, the matrix H _c,k is the normalized channel matrix between the cellular base station and the kth cellular user, satisfying The element [H _c,k ] _{m,n in row m and column n} is the channel coefficient between the antenna array element in row m and column n of the cellular base station and the kth cellular user k, superscript (·) ^H represents the conjugate transpose, E{· _} represents the average value, tr{·} represents the trace of the _matrix ; large-scale fading factor and the large-scale fading factor of the channel between the cell base station and RUE _i Vertical Transmit Correlator and horizontally send correlation array Among them, the matrix is the normalized channel matrix between the cell base station and RUE _i , satisfying The element in the mth row and the nth column is the channel coefficient between the antenna element in row m and column n of the cellular base station and RUE _i ; the large-scale fading factor of the channel between TUE _i and the kth cellular user

A specific downlink transmission and interference coordination method of a cellular and D2D hybrid communication network includes the following steps:

Step 1. Initialize the transmit power of each D2D communication pair to the maximum transmit power Set of D2D communication pairs with communication closed and cellular base station service user set initialized to an empty set;

Step 2. Using the known statistical channel information to calculate the key parameters of each D2D communication pair and cellular user, including:

1) For the kth cellular user CUE _k , k=1,...,L, calculate and in and are the DFT matrices of M _v ×M _v and M _h ×M _h respectively, and the elements of the mth row and the nth column are respectively and e is the natural base, and j' is the imaginary unit;

2) For the kth cellular user CUE _k , k=1,...,L, calculate and in and are respectively the a-th diagonal element of Λ _{V, c, k} and the b-th diagonal element of Λ _{H, c, k} , and let as well as

3) For RUE _i , i=1,...,N _s , calculate and

Step 3: Carry out cellular base station service user scheduling and calculate the scheduled service user set according to the following steps Each cellular user precoding vector in:

1.1) Select N'+1 integers and M′+1 integers Satisfy as well as Wherein N' is a positive integer less than M _h , and M' is a positive integer less than M _v ;

1.2) Divide all L cellular users into M'N' groups, and the division criterion is: if the kth cellular user satisfies and put it in the group in,

1.3) From each group of cellular users select their and The cellular user whose product is the largest, the number of selected cellular users is denoted as

1.4) If Where K is the maximum number of users served by the cellular base station at the same time, then the cellular users selected in step 1.3) are added to the cellular base station service user set Otherwise, the selected from step 1.3) Among the cellular users, select the and The K cellular users with the largest product will be added to the service user set of the cellular base station Collection of Cellular Service Users The number of cellular users is denoted as K _c ;

1.5) pair set Beamforming vectors for each cellular user computer in , assuming the set The lth cellular user in is Its beamforming vector The calculation method is where l=1,...,K _c , stands for Kroneck product operation, superscript ( ) ^* stands for conjugate, for the matrix First List, for the matrix First List;

Step 4: For each D2D communication pair, coordinate its interference to the cellular user one by one, and coordinate the interference to the cellular user for the i-th D2D communication pair as follows:

2.1) If the i-th D2D communication pair does not belong to Then let l=1 and enter step 2.2); otherwise, end the interference coordination of the D2D communication pair to the cellular user;

2.2) Calculate the i-th D2D communication pair set The lth cellular user in , assuming Interference measure of

in is the large-scale fading factor of the channel between the cellular base station and the k _lth cellular user, is the large-scale fading factor of the channel between TUE _i and the k _lth cellular user, and respectively First diagonal elements and First diagonal elements, and are the vertical transmission correlation matrix and horizontal transmission correlation matrix of the k _lth cellular user respectively, matrix is the normalized channel matrix between the cellular base station and the k _lth cellular user, and respectively The a-th diagonal element of and The bth diagonal element of ;

2.3) If is less than or equal to a preset threshold value δ ₁ , go to step 2.7); otherwise, go to step 2.4);

2.4) The transmission power of the i-th D2D communication pair reduced to be able to satisfy the i-th D2D communication pair-to-cellular user Interference measure of The maximum value less than or equal to the threshold value δ ₁ in, for

2.5) If Greater than or equal to the minimum transmit power of the D2D communication pair Go to step 2.7); otherwise, go to step 2.6);

2.6) Close the communication of the i-th D2D communication pair, that is, add it to the set And end the interference coordination of the i-th D2D communication pair to the cellular user;

2.7) Let l=l+1; if _l≤Kc , go to step 2.2), otherwise end the interference coordination of the i-th D2D communication pair to the cellular user;

Step 5: Coordinate the interference between the D2D communication pairs one by one, and coordinate the interference between the D2D communication pairs for the i-th D2D communication pair as follows:

3.1) If the i-th D2D communication pair does not belong to Then set j=1 and enter step 3.2); otherwise, end the D2D communication inter-pair interference coordination of the D2D communication pair;

3.2) If j≠i, enter step 3.3); otherwise, enter step 3.6);

3.3) If the i-th D2D communication pair does not belong to Then use the following formula to calculate its interference metric value for the i-th D2D communication pair

And go to step 3.4), where is the large-scale fading factor between the transmitter TUE _j of the j-th D2D communication pair and the receiver RUE _i of the i-th D2D communication pair, is the large-scale fading factor between the transmitter TUE _i and the receiver RUE _i of the i-th D2D communication pair; otherwise, go to step 3.6)

3.4) If is less than or equal to a certain preset threshold value δ _{2 )} , then go to step 3.6); otherwise, go to step 3.5);

3.5) Comparing large-scale fading factors and in is the large-scale fading factor between the sending end TUE _j and the receiving end RUE _j of the jth D2D communication pair; if Then close the communication of the jth D2D communication pair, that is, add it to the set And enter step 3.6); otherwise, close the communication of the i-th D2D communication pair, that is, add it to the set And end the D2D communication inter-pair interference coordination of the i-th D2D communication pair;

3.6) Let j=j+1; if j≤N _s , go to step 3.2), otherwise end the D2D communication inter-pair interference coordination of the i-th D2D communication pair;

Step 6: Coordinating the interference from the cell for the D2D communication pair one by one, wherein the coordination of the interference from the cell for the i-th D2D communication pair is performed as follows;

4.1) If the i-th D2D communication pair does not belong to Then enter step 4.2); otherwise, end the D2D communication interference coordination from the cell;

4.2) Calculation set The interference metric value of each cellular user to the i-th D2D communication pair in , assuming the set The lth cellular user in is but The interference metric value of the i-th D2D communication pair is denoted as Its calculation method is:

in and are respectively Λ _{H, d, i} 's diagonal elements and Λ _V,d,i'th diagonal elements;

4.3) Find the set The cellular user with the largest interference metric value for the i-th D2D communication pair is assumed to be the p- _th cellular user like Interference measure for the i-th D2D communication pair is less than or equal to a preset threshold value δ ₃ , then end the interference coordination of the D2D communication to the cell; otherwise, go to step 4.4);

4.4) Calculation and in and respectively The a-th diagonal element of and The bth diagonal element of , and are respectively the vertical transmission correlation matrix and the horizontal transmission correlation matrix of the p _i cellular user, the matrix is the normalized channel matrix between the cellular base station and the p _ith cellular user,

4.5) Calculation in vec( ) stands for matrix straightening operation, superscript T is transpose;

4.6) Calculation

4.7) Recalculate the p _ith cellular user The beamforming vector of make Wherein, q ₁ is the first column of Q; end the interference coordination of the D2D communication to the cell.

Step 7. After the interference coordination is completed, only the set The remaining cellular users in the precoded transmission will be aggregated The communication between the D2D communication pairs in is closed.

The above is only a preferred embodiment of the present invention, it should be pointed out that, for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications can also be made. It should be regarded as the protection scope of the present invention.

Claims (9)

1. A downlink transmission and interference coordination method for a cellular and D2D hybrid communication network, comprising the steps of:

step one, a plurality of D2D communication pairs sharing downlink frequency spectrum resources with the cellular base station exist in the coverage area of the cellular base station in the hybrid network, and the cellular base station adopts a uniform planar antenna array and comprises an M_vThe antenna elements are arranged in the vertical direction, and each row in the horizontal direction is M_hArray element with total transmitting power of P_c(ii) a The number of cellular users in the hybrid network is L, and the kth cellular user is recorded as CUE_k(ii) a The ith D2D communication pair includesSending terminal TUE_iAnd receiving end RUE_iAll equipped with a single antenna, the transmission power of whichMaximum isAt a minimum ofWherein, i is 1, …, N_s，N_sThe number of D2D communication pairs in the hybrid network;

firstly, the transmission power of each D2D communication pairInitialisation to maximum transmit powerD2D communication pair set with communication closedAnd cellular base station serving user setInitializing to an empty set;

secondly, calculating key parameters of each D2D communication pair and a cellular user by using the known statistical channel information;

step three, carrying out cellular base station service user scheduling and calculating a scheduled service user setPrecoding vectors of each cellular user;

step four, coordinating interference of each D2D communication pair on cellular users one by one;

step five, coordinating interference between D2D communication pairs one by one;

step six, coordinating interference from the cells for D2D communication pairs one by one;

step seven, only the sets are collected after the interference coordination is finishedThe rest cellular users carry out pre-coding transmission and are collectedThe communication between the D2D communication pair in (1) is closed.

2. The method as claimed in claim 1, wherein the statistical channel information in step two comprises:

large scale fading factor of channel between cellular base station and kth cellular userWhere k is 1, …, L, vertical transmit correlation matrix for kth cellular userCorrelation array for horizontal transmissionWherein, the matrix H_c,kIs a normalized channel matrix between the cellular base station and the k cellular userElement [ H ] of mth row and nth column_c,k]_m,nFor the channel coefficient between the m row and n column antenna element of the cellular base station and the k cellular user, superscript (-) is^HRepresenting conjugate transpose, E {. cndot } representing averaging, tr {. cndot } representing trace of matrix; transmitting end TUE of ith D2D communication pair_iReceiving end RUE of j-th communication pair D2D_jLarge scale fading factor in betweenAnd cellular base station and RUE_iLarge scale fading factor of inter-channelVertical transmit correlation arrayCorrelation array for horizontal transmissionWherein, the matrixFor cellular base stations and RUEs_iNormalized channel matrix of cells satisfyingElement [ H ] of mth row and nth column_di]_m,nFor the m row and n column antenna element and RUE of the cellular base station_iInter-channel coefficients; TUE_iLarge scale fading factor of channel with kth cellular user

3. The downlink transmission and interference coordination method for a cellular and D2D hybrid communication network according to claim 2, wherein the step two in which the cellular base station calculates the key parameters of each D2D communication pair and the cellular user by using the statistical channel information includes:

1) for the k cellular user, calculateAndwherein,andare respectively M_v×M_vAnd M_h×M_hThe elements of the m-th row and the n-th column of the DFT matrix are respectivelyAnde is a natural base number, j' is an imaginary unit;

2) for the k cellular user, calculateAndwherein,andare respectively Λ_V,c,kA diagonal element sum of_H,c,kThe b-th diagonal element of (1), andand

3) for RUE_iCalculatingAnd

4. the method as claimed in claim 3, wherein the third step is as follows:

1.1) selection of N' +1 integersAnd M' +1 integersSatisfy the requirement ofAndwherein N' is less than M_hM' is less than M_vA positive integer of (d);

1.2) dividing all L cellular users into M 'N' groups, wherein the division criterion is as follows: if the k cellular user is satisfiedAnd isThen it is classified into groups

1.3) selecting one from each group of cellular usersAndthe selected cell users are counted as the cell users with the largest product

1.4) ifWherein K is the maximum number of users served by the cellular base station at the same time, adding the cellular user selected in the step 1.3) into the cellular base station service user setOtherwise, selected from step 1.3)Among cellular users, selects itAndthe K cellular users with the maximum product are added into the cellular base station service user setCellular service user setThe number of the Chinese cell users is recorded as K_c；

1.5) set of pairsEach cellular user in (1) calculates its beamforming vector, setThe first cellular user in (1) isIts beam forming vectorIs calculated byWhere l is 1, …, K_c，Representing the operation of the Kroneck product, superscript (. cndot.)^*Represents the conjugate of the compound (I),is a matrixTo (1) aThe columns of the image data are,is a matrixTo (1) aAnd (4) columns.

5. The method of claim 4, wherein the interference coordination method for downlink transmission of cellular and D2D hybrid communication network is specifically as follows for the ith D2D communication pair in the fourth step:

2.1) if the ith D2D communication pair does not belong toLet l equal to 1 and go to step 2.2); otherwise, ending the interference coordination of the D2D communication pair to the cellular user;

2.2) computing the set of i-th D2D communication pairsThe ith cellular user inInterference metric of

2.3) ifLess than or equal to a predetermined threshold value delta₁Go to step 2.7); otherwise, entering step 2.4);

2.4) Transmission Power of the ith D2D communication pairDown to the point where the ith D2D communication pair can be satisfied for cellular usersInterference metric ofIs less than or equal to the threshold value delta₁Maximum value of

2.5) ifGreater than or equal to D2D communication pairMinimum transmission power ofGo to step 2.7); otherwise, entering step 2.6);

2.6) close communication of the ith D2D communication pair, i.e. join it into the setAnd end the interference coordination of the ith D2D communication pair to the cellular user;

2.7) let l ═ l + 1; if l is less than or equal to K_cGo to step 2.2), otherwise end the interference coordination for the cellular user by the ith D2D communication pair.

6. The downlink transmission and interference coordination method for cellular and D2D hybrid communication network as claimed in claim 5, wherein in said fifth step, the interference between the i-th D2D communication pair and the coordinated D2D communication pair is specifically as follows:

3.1) if the ith D2D communication pair does not belong toLet j equal 1 and go to step 3.2); otherwise, ending the D2D communication pair interference coordination of the D2D communication pair;

3.2) if j ≠ i, then step 3.3) is entered; otherwise, entering step 3.6);

3.3) if the jth D2D communication pair does not belong toThen its interference metric value for the ith D2D communication pair is calculated using the following equation

<mrow> <msub> <mi>J</mi> <mrow> <msub> <mi>d</mi> <mi>j</mi> </msub> <mo>,</mo> <msub> <mi>d</mi> <mi>i</mi> </msub> </mrow> </msub> <mo>=</mo> <msub> <mi>&amp;beta;</mi> <msub> <mi>d</mi> <mrow> <mi>j</mi> <mo>,</mo> <mi>i</mi> </mrow> </msub> </msub> <mo>/</mo> <msub> <mi>&amp;beta;</mi> <msub> <mi>d</mi> <mrow> <mi>i</mi> <mo>,</mo> <mi>i</mi> </mrow> </msub> </msub> <mo>,</mo> </mrow>

And go to step 3.4) whereTransmitting end TUE for jth D2D communication pair_jReceiving end RUE of communication pair with i-th D2D_iA large-scale fading factor in between,transmitting end TUE for ith D2D communication pair_iAnd its receiving end RUE_iLarge scale fading factors in between; otherwise, entering step 3.6);

3.4) ifLess than or equal to a predetermined threshold value delta₂Then go to step 3.6); otherwise, entering step 3.5);

3.5) larger scale fading factorAndwhereinTransmitting end TUE for jth D2D communication pair_jAnd its receiving endRUE_jLarge scale fading factors in between; if it isThen the communication of the jth D2D communication pair is closed, i.e. joined to the setAnd go to step 3.6); otherwise, the communication of the ith D2D communication pair is closed, i.e. added to the setAnd end the D2D communication pair inter-pair interference coordination for the ith D2D communication pair;

3.6) let j ═ j + 1; if j is less than or equal to N_sGo to step 3.2), otherwise end the inter-D2D communication pair interference coordination of the i-th D2D communication pair.

7. The method of claim 6, wherein the step six of coordinating interference from the cell for the ith D2D communication pair is performed by the following steps:

4.1) if the ith D2D communication pair does not belong toStep 4.2) is entered; otherwise, ending the interference coordination from the D2D communication to the cell;

4.2) computing the setThe interference metric value of each cellular user to the ith D2D communication pair is setThe first cellular user in (1) isThenThe interference metric for the ith D2D communication pair is recorded as

4.3) finding collectionsThe cellular user with the largest interference metric value for the ith D2D communication pair is set as the pth_iA cellular subscriberIf it isInterference metric value for ith D2D communication pairLess than or equal to a predetermined threshold value delta₃Then the interference coordination from the macro cell for the D2D communication is ended; otherwise, entering step 4.4);

4.4) calculationAndwhereinAndare respectively asA diagonal element ofThe b-th diagonal element of (a),andare respectively p_iVertical and horizontal transmit correlation arrays, matrices, for individual cellular usersIs a cellular base station and the p-th_iA normalized channel matrix between the individual cellular users,

4.5) calculationWherein vec (-) represents matrix straightening operation, and superscript T is transposition;

4.6) calculation

4.7) recalculating the p-th_iA cellular subscriberBeamforming vector ofOrder toWherein q is₁A first column of Q; the interference coordination from the cell for the D2D communication is ended.

8. The downlink transmission and interference coordination method for cellular and D2D hybrid communication network according to claim 7, wherein the ith D2D communication pair in step 2.2) is kth_lInterference metric for individual cellular usersThe calculation method comprises the following steps:

<mrow> <msub> <mi>J</mi> <mrow> <msub> <mi>d</mi> <mi>i</mi> </msub> <mo>,</mo> <msub> <mi>k</mi> <mi>l</mi> </msub> </mrow> </msub> <mo>=</mo> <mfrac> <mrow> <msub> <mi>K</mi> <mi>c</mi> </msub> <msub> <mi>P</mi> <msub> <mi>d</mi> <mi>i</mi> </msub> </msub> <msub> <mi>&amp;beta;</mi> <mrow> <msub> <mi>d</mi> <mi>i</mi> </msub> <mo>,</mo> <msub> <mi>k</mi> <mi>l</mi> </msub> </mrow> </msub> </mrow> <mrow> <msubsup> <mi>&amp;lambda;</mi> <mrow> <mi>V</mi> <mo>,</mo> <mi>c</mi> <mo>,</mo> <msub> <mi>k</mi> <mi>l</mi> </msub> </mrow> <mrow> <mo>(</mo> <msub> <mi>v</mi> <msub> <mi>k</mi> <mi>l</mi> </msub> </msub> <mo>)</mo> </mrow> </msubsup> <msubsup> <mi>&amp;lambda;</mi> <mrow> <mi>H</mi> <mo>,</mo> <mi>c</mi> <mo>,</mo> <msub> <mi>k</mi> <mi>l</mi> </msub> </mrow> <mrow> <mo>(</mo> <msub> <mi>h</mi> <msub> <mi>k</mi> <mi>l</mi> </msub> </msub> <mo>)</mo> </mrow> </msubsup> <msub> <mi>P</mi> <mi>c</mi> </msub> <msub> <mi>&amp;beta;</mi> <msub> <mi>c</mi> <msub> <mi>k</mi> <mi>l</mi> </msub> </msub> </msub> </mrow> </mfrac> <mo>,</mo> </mrow>

and is satisfied in step 2.4)Is less than or equal to the threshold value delta₁Maximum transmission power ofIs composed of

<mrow> <msub> <mover> <mi>P</mi> <mo>&amp;OverBar;</mo> </mover> <msub> <mi>d</mi> <mi>i</mi> </msub> </msub> <mo>=</mo> <msub> <mi>&amp;delta;</mi> <mn>1</mn> </msub> <msub> <mi>P</mi> <mi>c</mi> </msub> <msub> <mi>&amp;beta;</mi> <msub> <mi>c</mi> <msub> <mi>k</mi> <mi>l</mi> </msub> </msub> </msub> <msubsup> <mi>&amp;lambda;</mi> <mrow> <mi>V</mi> <mo>,</mo> <mi>c</mi> <mo>,</mo> <msub> <mi>k</mi> <mi>l</mi> </msub> </mrow> <mrow> <mo>(</mo> <msub> <mi>v</mi> <msub> <mi>k</mi> <mi>l</mi> </msub> </msub> <mo>)</mo> </mrow> </msubsup> <msubsup> <mi>&amp;lambda;</mi> <mrow> <mi>H</mi> <mo>,</mo> <mi>c</mi> <mo>,</mo> <msub> <mi>k</mi> <mi>l</mi> </msub> </mrow> <mrow> <mo>(</mo> <msub> <mi>h</mi> <msub> <mi>k</mi> <mi>l</mi> </msub> </msub> <mo>)</mo> </mrow> </msubsup> <mo>/</mo> <msub> <mi>K</mi> <mi>c</mi> </msub> <msub> <mi>&amp;beta;</mi> <mrow> <msub> <mi>d</mi> <mi>i</mi> </msub> <mo>,</mo> <msub> <mi>k</mi> <mi>l</mi> </msub> </mrow> </msub> <mo>,</mo> </mrow>

WhereinIs a cellular base station and k_lThe large scale fading factor of the channel between the cellular users,is TUE_iAnd k is_lThe large scale fading factor of the channel between the cellular users,andare respectively asTo (1) aA pair of angle elementsTo (1) aThe number of the diagonal elements is equal to the number of the diagonal elements,andare respectively k_lVertical and horizontal transmit correlation arrays, matrices, for individual cellular usersIs a cellular base station and k_lA normalized channel matrix between the individual cellular users, andare respectively asA diagonal element ofThe b-th diagonal element of (1).

9. The downlink transmission and interference coordination for a cellular and D2D hybrid communication network according to claim 8The method is characterized in that the method is integrated in the step 4.2)The first macrocell user is set asInterference metric value for ith D2D communication pairThe calculation method comprises the following steps:

<mrow> <msub> <mi>J</mi> <mrow> <msub> <mi>k</mi> <mi>l</mi> </msub> <mo>,</mo> <msub> <mi>d</mi> <mi>i</mi> </msub> </mrow> </msub> <mo>=</mo> <mfrac> <mrow> <msubsup> <mi>&amp;lambda;</mi> <mrow> <mi>V</mi> <mo>,</mo> <mi>d</mi> <mo>,</mo> <mi>i</mi> </mrow> <mrow> <mo>(</mo> <msub> <mi>v</mi> <msub> <mi>k</mi> <mi>l</mi> </msub> </msub> <mo>)</mo> </mrow> </msubsup> <msubsup> <mi>&amp;lambda;</mi> <mrow> <mi>H</mi> <mo>,</mo> <mi>d</mi> <mo>,</mo> <mi>i</mi> </mrow> <mrow> <mo>(</mo> <msub> <mi>h</mi> <msub> <mi>k</mi> <mi>l</mi> </msub> </msub> <mo>)</mo> </mrow> </msubsup> <msub> <mi>P</mi> <mi>c</mi> </msub> <msub> <mi>&amp;beta;</mi> <mrow> <mi>c</mi> <mo>,</mo> <msub> <mi>d</mi> <mi>i</mi> </msub> </mrow> </msub> </mrow> <mrow> <msub> <mi>K</mi> <mi>c</mi> </msub> <msub> <mi>P</mi> <msub> <mi>d</mi> <mi>i</mi> </msub> </msub> <msub> <mi>&amp;beta;</mi> <msub> <mi>d</mi> <mrow> <mi>i</mi> <mo>,</mo> <mi>i</mi> </mrow> </msub> </msub> </mrow> </mfrac> <mo>,</mo> </mrow>

whereinAndare respectively Λ_H,d,iTo (1) aA diagonal element sum Λ_V,d,iTo (1) aAnd a diagonal element.