CN102104880B - Interference coordination method among downlink cells in relay wireless communication network - Google Patents

Abstract

The invention relates to an interference coordination method among downlink cells in a relay wireless communication network, belonging to the technical field of wireless communication. The base station of the downlink of the relay wireless communication network divides the user area of the cell into non-interference user and interference user according to amount and position of users on the adjacent cell service edge, traditional transmission mode is adopted for the non-interference user, and interference evaded transmission mode is adopted for the interference user. In the interference evaded transmission mode, a relay carries out wave beam forming on the position information of the adjacent cell-edge user and the channel information of the cell interference user so that the interference of the adjacent cell-edge user is effectively evaded. In the method, when all cells adopt the interference evading policy, the performance of all cell-edge users can be effectively protected so that the throughput of the cell-edge user can be improved.

Description

Descending inter-cell interference coordination method in a kind of relay wireless communications network

Technical field

The present invention relates to the descending inter-cell interference coordination method in a kind of relay wireless communications network, belong to technical field of wireless communication.

Background technology

In cellular system, it is strong that the user of cell edge receives signal energy presence of intercell interference energy poor, that be subjected to, so the communication link quality of Cell Edge User is lower, often can not satisfy the demand of QoS of customer (QoS).Cellular system can adopt the Inter-Cell Interference Coordination technology to manage presence of intercell interference, adopts relaying technique to improve the communication quality of Cell Edge User.

Because Cell Edge User is far away apart from the base station, when directly transmission was adopted in the base station, the signal energy that edge customer can effectively receive was lower.Will introduce more serious presence of intercell interference if improve base station transmitting power.If the base station is issued the relay station near cell edge earlier, be transmitted to Cell Edge User by relay station again, Cell Edge User just can receive stronger signal like this.Because the transmitting power of relaying is lower with respect to the base station, therefore the interference coverage that produces is little, relatively is applicable to the user at Serving cell edge.

Aspect Inter-Cell Interference Coordination, traditional analogue cellular network and GSM cellular network reduce presence of intercell interference by improving frequency duplex factor as one, thereby guarantee the reliability of Cell Edge User.But higher frequency duplex factor as one can the serious spectrum efficiency that reduces cellular system.Present LTE system adopts interference coordination technique such as power control, presence of intercell interference deletion, soft-frequency reuse technology, presence of intercell interference randomization, beam forming to improve the performance of edge customer.

Up-link adopts technology such as power control, presence of intercell interference deletion to carry out interference coordination more.Chinese patent 200810065659 (a kind of inter-cell interference coordination method of relay wireless communications network, 2009 07 month) a kind of inter-cell interference coordination method of relay wireless communications network disclosed, can select to insert relaying or base station by the user, and control to coordinate to disturb between uplink cells in conjunction with transmitting power.Downlink system adopts technology such as soft-frequency reuse, beam forming to carry out Inter-Cell Interference Coordination more.Technology motion R1-060517 (the Further analysis of theperformance of inter-cell interference mitigation with beam-forming of China Mobile in 3GPP work, in February, 2006) just point out, beam forming can be given full play to the advantage of multi-antenna technology, avoid interference by the direction of adjusting wave beam, improve the performance of Cell Edge User.In addition, the beam forming technology also is combined the presence of intercell interference of disinthibiting jointly easily with other perturbation techniques.

Traditional system adopts beam forming in the base station, and is low to the user's resolution capability that is in cell edge simultaneously because the user of base station service is more, is difficult to carry out effective jam avoidance.And relay station is generally at the edge of residential quarter, and the user of service is less, and distinguishes the edge customer of diverse location easily, can realize avoiding than the more effective area interference in base station.

Summary of the invention

The objective of the invention is to propose the descending inter-cell interference coordination method in a kind of relay wireless communications network, the base station adopts different mode to serve the user of this residential quarter according to the situation of adjacent base station Serving cell edge customer, for meeting the neighbor cell edge customer being produced the serious user who disturbs utilizes the spatial beams moulding to avoid interference, thereby effectively reduce the interference that Cell Edge User is subjected to, and improve the throughput of all cell edges.

Descending inter-cell interference coordination method in the relay wireless communications network that the present invention proposes comprises following each step:

(1) the jam avoidance request is sent to the base station of neighbor cell in each base station in the down link of relay wireless communications network, if contain the user who is in cell edge among the user of this service, then edge customer is called " protection user ", comprise the number of " protection user " in the jam avoidance request that send to neighbor cell base station the base station, and comprise the positional information of " protection user "; If do not contain the user who is in cell edge among the user of this service, then number that will " protection user " in the jam avoidance request of sending to neighbor cell base station is designated as zero;

(2) the jam avoidance request of each reception of neighboring cell base station, base station, if the number of " protection user " is zero in the neighbor cell, then all users of this residential quarter are non-interference user, if the number of " protection user " is non-vanishing in the neighbor cell, then with neighbor cell in the user of adjacent this residential quarter, " protection user " position be interference user, other users are non-interference user;

(3) the traditional mode transmission is adopted to the non-interference user of this residential quarter in each base station, and interference user is adopted the jam avoidance mode transfer, and detailed process is as follows:

(3-1) establish and have N interference user in this residential quarter, there be K protection user in neighbor cell, and relay station in the down link that user position information sends to the relay wireless communications network is simultaneously protected with the data to be transmitted of N interference user and K in the base station;

(3-2) relay station to this residential quarter n (n=1 ..., the launching beam vector that adopts when N) individual interference user sends data to be transmitted is:

$p_n=h_n^H{(\underset{m=1}{\overset{N}{\mathrm{\Σ}}}{h}_m{h}_m^H+\underset{k=1}{\overset{K}{\mathrm{\Σ}}}{R}_k)}^{-1}$

H wherein _nBe relay station to n (n=1 ..., the N) channel response of individual interference user;

Expression relay station and k (k=1 ..., K) the relevant battle array of individual protection user's channel;

$a\left(\mathrm{\θ}\right)=[1,\exp \left(j2\mathrm{\π}\frac{d}{\mathrm{\λ}}\sin \mathrm{\θ}\right),\mathrm{\Λ},\exp \left(j2\mathrm{\π}(M-1)\frac{d}{\mathrm{\λ}}\sin \mathrm{\θ}\right)]$ It is the battle array bunch vector on the relay station M transmitting antenna;

${\mathrm{\θ}}_{k,i}={\mathrm{\θ}}_k+(\frac{i}{D}-\frac{1}{2})\mathrm{\φ},i=1,...,D;$

α _kThe expression relay station is to k protection user's path loss;

θ _kThe expression relay station is to k protection user's the angle of arrival;

D represents the scattering object number around the relay station;

φ represents the angle spread of relay station antenna;

D represents the spacing of relay station antenna;

λ represents the wavelength of wireless signal.

Annotate: d and λ belong to system's preset parameter, and D and φ can determine α by the communication environment of relay station _kAnd θ _kCan determine h by the positional information of protection user and relay station _nCan utilize the up-downgoing duality in up link, to estimate to obtain.

Descending inter-cell interference coordination method in the relay wireless communications network that the present invention proposes has the following advantages:

(1) the present invention adopts relaying to come the Serving cell edge customer to replace the direct Serving cell edge customer in base station, can reduce area interference like this when improving the Cell Edge User link-quality;

(2) in the present invention, relay station is littler than the beam coverage of the formation of base station, and is strong to the position resolution of edge customer, thus relay station to carry out interference coordination more flexible, it is better to obtain to carry out the interference coordination performance than the base station simultaneously;

(3) in the present invention, do not need protected user's instantaneous channel information when relay station carries out interference coordination, and only need this user position information, so the information that exchanges between the base station is few, the signaling consumption in the time of can effectively saving exchange message.

Description of drawings

Fig. 1 is the FB(flow block) of the inventive method.

Fig. 2 is the signal transmission schematic diagram of base station 1 noiseless universal time coordinated.

Fig. 3 is the signal transmission schematic diagram of base station 1 when interference coordination is arranged.

Fig. 4 is base station 1 and the base station 2 signal transmission schematic diagram when interference coordination is arranged.

Embodiment

Descending inter-cell interference coordination method in the relay wireless communications network that the present invention proposes, its FB(flow block) comprises following each step as shown in Figure 1:

(1) the jam avoidance request is sent to the base station of neighbor cell in each base station in the down link of relay wireless communications network, if contain the user who is in cell edge among the user of this service, then edge customer is called " protection user ", comprise the number of " protection user " in the jam avoidance request that send to neighbor cell base station the base station, and comprise the positional information of " protection user "; If do not contain the user who is in cell edge among the user of this service, then number that will " protection user " in the jam avoidance request of sending to neighbor cell base station is designated as zero;

(2) the jam avoidance request of each reception of neighboring cell base station, base station, if the number of " protection user " is zero in the neighbor cell, then all users of this residential quarter are non-interference user, if the number of " protection user " is non-vanishing in the neighbor cell, then with neighbor cell in the user of adjacent this residential quarter, " protection user " position be interference user, other users are non-interference user;

(3) the traditional mode transmission is adopted to the non-interference user of this residential quarter in each base station, and interference user is adopted the jam avoidance mode transfer, and detailed process is as follows:

(3-1) establish and have N interference user in this residential quarter, there be K protection user in neighbor cell, and relay station in the down link that user position information sends to the relay wireless communications network is simultaneously protected with the data to be transmitted of N interference user and K in the base station;

(3-2) relay station to this residential quarter n (n=1 ..., the launching beam vector that adopts when N) individual interference user sends data to be transmitted is:

$p_n=h_n^H{(\underset{m=1}{\overset{N}{\mathrm{\Σ}}}{h}_m{h}_m^H+\underset{k=1}{\overset{K}{\mathrm{\Σ}}}{R}_k)}^{-1}$

H wherein _nBe relay station to n (n=1 ..., the N) channel response of individual interference user;

Expression relay station and k (k=1 ..., K) the relevant battle array of individual protection user's channel;

$a\left(\mathrm{\θ}\right)=[1,\exp \left(j2\mathrm{\π}\frac{d}{\mathrm{\λ}}\sin \mathrm{\θ}\right),\mathrm{\Λ},\exp \left(j2\mathrm{\π}(M-1)\frac{d}{\mathrm{\λ}}\sin \mathrm{\θ}\right)]$ It is the battle array bunch vector on the relay station M transmitting antenna;

${\mathrm{\θ}}_{k,i}={\mathrm{\θ}}_k+(\frac{i}{D}-\frac{1}{2})\mathrm{\φ},i=1,...,D;$

α _kThe expression relay station is to k protection user's path loss;

θ _kThe expression relay station is to k protection user's the angle of arrival;

D represents the scattering object number around the relay station;

φ represents the angle spread of relay station antenna;

D represents the spacing of relay station antenna;

λ represents the wavelength of wireless signal.

Below in conjunction with accompanying drawing and example the inventive method is further specified.

As shown in Figure 2, in downlink communication, base station 1 service-user 1, base station 2 service-users 2.Because user 1 and user's 2 position is more close, and all near cell edge, so can produce serious disturbance to user 2 during 1 service-user 1 of base station.In this law invention, base station 1 and base station 2 send the jam avoidance request mutually.Be example with base station 2; base station 2 finds that users 2 are in the marginal position of residential quarter, therefore user 2 is divided into " protection user ", therefore in the jam avoidance request of sending to base station 1; the number of " protection user " is 1, and the position of " protection user " is exactly user 2 position.

Base station 1 at first receives the jam avoidance request of sending base station 2; the user 2 that the user 1 of discovery base station 1 service asks for protection apart from base station 2 is very near; therefore service-user 1 can produce serious the interference to user 2; therefore base station 1 divides user 1 into interference user, and adopts the jam avoidance pattern to transmit to user 1.When 1 couple of user in base station 1 adopted the jam avoidance pattern to transmit, base station 1 at first sent to relay station 1 with user 1 data and user 2 positional information, and the launching beam that 1 couple of user of relay station 1 adopts can be expressed as:

$p_1=h_{11}^H{(h_{11}{h}_{11}^H+R_{12})}^{-1}$

H wherein ₁₁Be that relay station 1 is to user 1 channel response;

Relevant gust of expression relay station 1 and user's 2 channel;

$a\left(\mathrm{\θ}\right)=[1,\exp \left(j2\mathrm{\π}\frac{d}{\mathrm{\λ}}\sin \mathrm{\θ}\right),\mathrm{\Λ},\exp \left(j2\mathrm{\π}(M-1)\frac{d}{\mathrm{\λ}}\sin \mathrm{\θ}\right)]$ It is the battle array bunch vector on the relay station M transmitting antenna;

${\mathrm{\θ}}_{1,i}={\mathrm{\θ}}_{12}+(\frac{i}{D_1}-\frac{1}{2}){\mathrm{\φ}}_1,i=1,...,D_1;$

α ₁₂Expression relay station 1 is to user 2 path loss;

θ ₁₂Expression relay station 1 is to user 2 the angle of arrival;

D ₁Scattering object number around the expression relay station 1;

φ ₁The angle spread of expression relay station 1 antenna;

D represents the spacing of relay station antenna;

λ represents the wavelength of wireless signal.

After relay station 1 adopted above-mentioned launching beam, as shown in Figure 3, relay station 1 positional information according to user 2 when service-user 1 was carried out jam avoidance, thereby has protected user 2 performance.

In like manner; base station 2 receives the jam avoidance request that send base station 1; the user 1 that the user 2 of discovery base station 2 services asks for protection apart from base station 1 is very near; therefore service-user 2 can produce serious the interference to user 1; therefore base station 2 divides user 2 into interference user, and adopts the jam avoidance pattern to transmit to user 2.Therefore, base station 2 sends to relay station 2 with user 2 data and user 1 positional information, and the launching beam that 2 couples of users of relay station 2 adopt can be expressed as:

$p_2=h_{22}^H{(h_{22}{h}_{22}^H+R_{21})}^{-1}$

H wherein ₂₂Be that relay station 2 is to user 2 channel response;

Relevant gust of expression relay station 2 and user's 1 channel;

$a\left(\mathrm{\θ}\right)=[1,\exp \left(j2\mathrm{\π}\frac{d}{\mathrm{\λ}}\sin \mathrm{\θ}\right),\mathrm{\Λ},\exp \left(j2\mathrm{\π}(M-1)\frac{d}{\mathrm{\λ}}\sin \mathrm{\θ}\right)]$ It is the battle array bunch vector on the relay station M transmitting antenna;

${\mathrm{\θ}}_{2,i}={\mathrm{\θ}}_{21}+(\frac{i}{D_2}-\frac{1}{2}){\mathrm{\φ}}_2,i=1,...,D_2;$

α ₂₁Expression relay station 2 is to user 1 path loss;

θ ₂₁Expression relay station 2 is to user 1 the angle of arrival;

D ₂Scattering object number around the expression relay station 2;

φ ₂The angle spread of expression relay station 2 antennas;

D represents the spacing of relay station antenna;

λ represents the wavelength of wireless signal.

After relay station 2 adopted above-mentioned launching beam, as shown in Figure 4, relay station 2 positional information according to user 1 when service-user 2 was carried out jam avoidance, thereby has protected user 1 performance.All adopt the jam avoidance mode service to be in user 1 and the user 2 of cell edge when base station 1 and base station 2, then can effectively reduce the presence of intercell interference that user 1 and user 2 are subjected to, thereby improve the performance of edge customer.

Claims (1)

1. the descending inter-cell interference coordination method in the relay wireless communications network is characterized in that this method comprises following each step:

(1) the jam avoidance request is sent to the base station of neighbor cell in each base station in the down link of relay wireless communications network, if contain the user who is in cell edge among the user of this service, then edge customer is called " protection user ", comprise the number of " protection user " in the jam avoidance request that send to neighbor cell base station the base station, and comprise the positional information of " protection user "; If do not contain the user who is in cell edge among the user of this service, then number that will " protection user " in the jam avoidance request of sending to neighbor cell base station is designated as zero;

(2) the jam avoidance request of each reception of neighboring cell base station, base station, if the number of " protection user " is zero in the neighbor cell, then all users of this residential quarter are non-interference user, if the number of " protection user " is non-vanishing in the neighbor cell, then with neighbor cell in the user of adjacent this residential quarter, " protection user " position be interference user, other users are non-interference user;

(3) the traditional mode transmission is adopted to the non-interference user of this residential quarter in each base station, and interference user is adopted the jam avoidance mode transfer, and detailed process is as follows:

(3-1) establish and have N interference user in this residential quarter, there be K protection user in neighbor cell, and this residential quarter relay station in the down link that user position information sends to the relay wireless communications network is simultaneously protected with the data to be transmitted of N interference user and K in the base station;

(3-2) launching beam vector from data to be transmitted to this residential quarter that adopt when n interference user sends of this residential quarter relay station is:

$p_n=h_n^H{(\underset{m=1}{\overset{N}{\mathrm{\Σ}}}{h}_m{h}_m^H+\underset{k=1}{\overset{K}{\mathrm{\Σ}}}{R}_k)}^{-1}$

H wherein _nBe this residential quarter relay station to the channel response of n interference user, n=1 wherein ..., N;

Relevant gust of channel representing this residential quarter relay station and k protection user, k=1 wherein ..., K;

$a\left(\mathrm{\θ}\right)=[1,\exp \left(j2\mathrm{\π}\frac{d}{\mathrm{\λ}}\sin \mathrm{\θ}\right),\·\·\·,\exp \left(j2\mathrm{\π}(M-1)\frac{d}{\mathrm{\λ}}\sin \mathrm{\θ}\right)]$ It is the battle array bunch vector on the relay station M transmitting antenna;

${\mathrm{\θ}}_{k,i}={\mathrm{\θ}}_k+(\frac{i}{D}-\frac{1}{2})\mathrm{\φ},i=1,...,D;$

α _kRepresent that this residential quarter relay station is to k protection user's path loss;

θ _kRepresent that this residential quarter relay station is to k protection user's the angle of arrival;

D represents the scattering object number around this residential quarter relay station;

φ represents the angle spread of this residential quarter relay station antenna;

D represents the spacing of relay station antenna;

λ represents the wavelength of wireless signal.

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