CN104283597A

CN104283597A - A beamforming method and device

Info

Publication number: CN104283597A
Application number: CN201310607975.6A
Authority: CN
Inventors: 崔高峰; 王卫东; 吕程程; 赵丽娜; 唐明环
Original assignee: Beijing University of Posts and Telecommunications
Current assignee: Aerospace Xingyun Technology Co ltd
Priority date: 2013-11-25
Filing date: 2013-11-25
Publication date: 2015-01-14
Anticipated expiration: 2033-11-25
Also published as: CN104283597B

Abstract

The invention provides a method and device for shaping wave beams. The method includes the steps of obtaining position information of users to be served by a current time slot, determining a handling capacity function of the total handling capacity of the users relative to downward inclination angle combinations according to the position information of the users, estimating the downward inclination angle combination by which the maximum value of the handling capacity function is obtained with the DIRECT algorithm, and then adjusting the downward inclination angles of the two wave beams according to the downward inclination angle combination obtained through calculation. By means of the technical scheme, the system hanging capacity can be improved.

Description

A beamforming method and device

技术领域technical field

本发明涉及通信技术领域，尤其涉及到一种波束赋形方法及设备。The present invention relates to the technical field of communications, and in particular to a beamforming method and equipment.

背景技术Background technique

双波束下倾是指使同一个基站发送两个下倾角不同的波束为用户提供服务。现有技术中设置双波束的下倾角的方案一般包括两种：（1）为两个波束设置固定的下倾角；（2）将两个波束分别指向被服务的用户，对于第一种方案，不能根据用户的位置进行实时调整，无法保证用户达到最大的吞吐量，而第二种方案可能因为当前需要被服务的两个用户距离较近，产生较大的干扰，从而降低系统整体的吞吐量。Dual-beam downtilt means that the same base station sends two beams with different downtilt angles to provide services for users. In the prior art, there are generally two schemes for setting the downtilt angle of the dual beams: (1) setting a fixed downtilt angle for the two beams; (2) pointing the two beams to the served users respectively. For the first scheme, Real-time adjustments cannot be made according to the user's location, and the maximum throughput of the user cannot be guaranteed. The second solution may cause greater interference due to the short distance between the two users who need to be served, thereby reducing the overall throughput of the system. .

发明内容Contents of the invention

本发明提供了一种波束赋形方法及设备，能够提高系统的吞吐量。The invention provides a beam forming method and equipment, which can improve the throughput of the system.

本发明提供了一种波束赋形方法，应用于双波束通信系统中，该方法包括：The present invention provides a beamforming method, which is applied to a dual-beam communication system, and the method includes:

获取下一个时隙服务所要服务的各个用户的位置信息；Obtain the location information of each user to be served by the next time slot service;

根据获取到的位置信息选择各个用户的总吞吐量相对于下倾角组合（β₁，β₂）的总吞吐量函数β1和β2分别表示第1个波束和第2个波束的下倾角，R_i(β₁,β₂)为第i个用户对应的吞吐量相对于下倾角组合（β₁，β₂）的函数，I为两个波束服务的用户的个数；According to the obtained location information, select the total throughput function of the total throughput of each user relative to the combination of downtilt angles (β ₁ , β ₂ ) β1 and β2 represent the downtilt angles of the first beam and the second beam respectively, and R _i (β ₁ , β ₂ ) is the function of the throughput corresponding to the i-th user relative to the combination of downtilt angles (β ₁ , β ₂ ) , I is the number of users served by the two beams;

采用DIRECT算法计算使最大的下倾角组合（β_1M，β_2M）；Using the DIRECT algorithm to calculate the Maximum downtilt combination (β _1M , β _2M );

将两个波束的下倾角对应的调整为β_1M，β_2M。The downtilt angles of the two beams are correspondingly adjusted to β _1M and β _2M .

优选的，所述根据获取到的位置信息选择各个用户的总吞吐量相对于下倾角组合（β₁，β₂）的总吞吐量函数具体包括：Preferably, the total throughput function of selecting the total throughput of each user relative to the combination of downtilt angles (β ₁ , β ₂ ) according to the acquired location information Specifically include:

针对每一个用户，分别计算其对各个波束的接收功率，以及对各个波束的接收增益相对于下倾角组合（β₁，β₂）的函数；For each user, calculate the received power of each beam and the function of the received gain of each beam relative to the combination of downtilt angles (β ₁ , β ₂ );

取作为各个用户的总吞吐量相对于下倾角组合（β₁，β₂）的总吞吐量函数其中，Pick As a function of aggregate throughput for individual users with respect to the downtilt combination (β ₁ , β ₂ ) in,

$R R (({γ γ}_{11},, {γ γ}_{22},, M m)) = = {E E.}_{X x} [[{log log}_{22} ((11 + + X x))]] = = {log log}_{22} ((e e)) {Σ Σ}_{i i = = 00}^{M m - - 11} {Σ Σ}_{l l = = 00}^{i i} \frac{{γ γ}_{11}^{l l + + 11 - - i i}}{{γ γ}_{22} ((i i - - l l))!!} \cdot &Center Dot; {I I}_{11} ((\frac{11}{{γ γ}_{11}},, \frac{{γ γ}_{11}}{{γ γ}_{22}},, i i,, l l + + 11))$

其中I₁(a,b,m,n)为积分表达式，且where I ₁ (a,b,m,n) is an integral expression, and

${I I}_{11} ((a a,, b b,, m m,, n no)) = = {Σ Σ}_{i i = = 11}^{n no} \frac{{((- - 11))}^{i i - - 11}}{{((11 - - b b))}^{i i}} \cdot &Center Dot; {I I}_{22} ((a a,, b b,, m m,, n no - - i i + + 11)) + + \frac{{I I}_{22} ((a a,, 11,, m m,, 11))}{{((b b - - 11))}^{n no}};;$

${I I}_{22} ((a a,, b b,, m m,, n no)) = = {&Integral; &Integral;}_{00}^{\infty \infty} \frac{{x x}^{m m} {e e}^{- - ax ax}}{{((x x + + b b))}^{i i}} dx dx = = {e e}^{ab ab} {Σ Σ}_{i i = = 00}^{m m} (\begin{matrix} m m \\ i i \end{matrix}) {((- - b b))}^{m m - - i i} {I I}_{33} ((a a,, b b,, i i - - n no));;$

${I I}_{33} ((a a,, b b,, m m)) = = {&Integral; &Integral;}_{b b}^{\infty \infty} {x x}^{m m} {e e}^{- - ax ax} dx dx = = \{\begin{matrix} {e e}^{- - ab ab} {Σ Σ}_{i i = = 00}^{m m} \frac{m m!!}{i i!!} \frac{{b b}^{i i}}{{a a}^{m m - - i i + + 11}} & m m &GreaterEqual; &Greater Equal; 00 \\ {E E.}_{11} ((ab ab)) & m m = = - - 11 \\ \frac{{E E.}_{11} ((ab ab))}{{((- - a a))}^{- - m m - - 11} ((- - m m - - 11))!!} + + \frac{{e e}^{- - ab ab}}{{b b}^{- - m m - - 11}} {Σ Σ}_{i i = = 00}^{- - m m - - 22} \frac{{((- - ab ab))}^{i i} ((- - m m - - i i - - 22))!!}{((- - m m - - 11))!!} & m m \leq \leq - - 22 \end{matrix}$

其中，为第i个用户对第s个波束的接收功率，G_si(β_s)表示第i个用户对第s个波束的接收增益相对于第s个波束的下倾角β_s的函数。in, is the received power of the i-th user to the s-th beam, and G _si (β _s ) represents the function of the i-th user’s reception gain to the s-th beam relative to the downtilt angle β _s of the s-th beam.

优选的，所述针对每一个用户，分别计算其对各个波束的接收增益相对于下倾角组合（β₁，β₂）的函数，包括：Preferably, for each user, the function of calculating its receiving gain for each beam relative to the combination of downtilt angles (β ₁ , β ₂ ) includes:

通过如下公式计算第i个用户对第s个波束的接收增益G_si(β_s)：The receiving gain G _si (β _s ) of the i-th user to the s-th beam is calculated by the following formula:

其中，和θ_i分别为第i个用户对应的方位角和俯仰角，SLL_az和SLL_el分别是水平和和垂直方向图的旁瓣电平，SLL_tot是总的旁瓣电平，为第i个用户对第s波束的接收功率，为第i个用户所在基站的天线阵列瞄准轴与x轴的夹角。in, and _θi are the azimuth and elevation angles corresponding to the i-th user, respectively, SLL _az and SLL _el are the sidelobe levels of the horizontal and vertical patterns, respectively, and SLL _tot is the total sidelobe level, is the received power of the i-th user on the s-th beam, is the angle between the aiming axis of the antenna array of the base station where the i-th user is located and the x-axis.

本发明提供了一种波束赋形设备，作为基站应用于无线通信系统中，该设备包括：The present invention provides a beamforming device, which is used as a base station in a wireless communication system, and the device includes:

位置信息获取模块，用于获取下一个时隙服务所要服务的各个用户的位置信息；A location information acquisition module, configured to acquire the location information of each user to be served by the next time slot service;

函数调用模块，用于根据位置信息获取模块获取到的位置信息选择各个用户的总吞吐量相对于下倾角组合（β₁，β₂）的总吞吐量函数β1和β2分别表示第1个波束和第2个波束的下倾角，R_i(β₁,β₂)为第i个用户对应的吞吐量相对于下倾角组合（β₁，β₂）的函数，I为两个波束服务的用户的个数；A function calling module, used to select the total throughput function of the total throughput of each user relative to the combination of downtilt angles (β ₁ , β ₂ ) according to the location information obtained by the location information acquisition module β1 and β2 represent the downtilt angles of the first beam and the second beam respectively, and R _i (β ₁ , β ₂ ) is the function of the throughput corresponding to the i-th user relative to the combination of downtilt angles (β ₁ , β ₂ ) , I is the number of users served by the two beams;

计算模块，用于采用DIRECT算法计算使最大的下倾角组合（β_1M，β_2M）；Calculation module, for adopting DIRECT algorithm to calculate and use Maximum downtilt combination (β _1M , β _2M );

赋形模块，用于将两个波束的下倾角对应的调整为β_1M，β_2M。The shaping module is configured to correspondingly adjust the downtilt angles of the two beams to β _1M and β _2M .

优选的，所述函数调用模块具体用于根据获取到的位置信息确定每一个用户接收各个波束的信号强度相对于下倾角组合（β₁，β₂）的函数，取作为各个用户的总吞吐量相对于下倾角组合（β₁，β₂）的总吞吐量函数其中，Preferably, the function calling module is specifically configured to determine the function of the signal strength of each user receiving each beam relative to the combination of downtilt angles (β ₁ , β ₂ ) according to the acquired position information, taking As a function of aggregate throughput for individual users with respect to the downtilt combination (β ₁ , β ₂ ) in,

优选的，所述函数调用模块具体通过如下公式计算第i个用户对第s个波束的接收增益G_si(β_s)：Preferably, the function calling module specifically calculates the receiving gain G _si (β _s ) of the i-th user to the s-th beam by the following formula:

别是水平和和垂直方向图的旁瓣电平，SLL_tot是总的旁瓣电平，为第i个用户对第s波束的接收功率，为第i个用户所在基站的天线阵列瞄准轴与x轴的夹角。 are the sidelobe levels of the horizontal and vertical patterns, SLL _tot is the total sidelobe level, is the received power of the i-th user on the s-th beam, is the angle between the aiming axis of the antenna array of the base station where the i-th user is located and the x-axis.

本发明中，获取用户的位置信息，并根据用户的位置信息确定各个用户的总吞吐量相对于下倾角组合的吞吐量函数，并采用DIRECT算法估算使吞吐量函数取最大值的下倾角组合，之后根据计算得到的下倾角组合调整两个波束的下倾角。本发明提供的技术方案，能够提高系统的吞吐量。In the present invention, the user's location information is obtained, and according to the user's location information, the total throughput of each user is determined relative to the throughput function of the downtilt combination, and the DIRECT algorithm is used to estimate the downtilt combination that makes the throughput function take the maximum value, Then the downtilt angles of the two beams are adjusted according to the calculated downtilt angle combination. The technical scheme provided by the invention can improve the throughput of the system.

附图说明Description of drawings

图1为本发明实施例提供的一种波束赋形方法的流程示意图；FIG. 1 is a schematic flowchart of a beamforming method provided by an embodiment of the present invention;

图2为本发明是实施例提供的波束赋形方法的一种应用场景的示意图；FIG. 2 is a schematic diagram of an application scenario of a beamforming method provided by an embodiment of the present invention;

图3为本发明是实施例提供的波束赋形方法的一种应用场景的示意图；FIG. 3 is a schematic diagram of an application scenario of a beamforming method provided by an embodiment of the present invention;

图4为本发明是实施例提供的一种波束赋形设备的结构示意图。Fig. 4 is a schematic structural diagram of a beamforming device provided by an embodiment of the present invention.

具体实施方式Detailed ways

下面结合附图和实施例，对本发明的具体实施方式作进一步描述。以下实施例仅用于更加清楚地说明本发明的技术方案，而不能以此来限制本发明的保护范围。The specific implementation manners of the present invention will be further described below in conjunction with the drawings and examples. The following examples are only used to illustrate the technical solution of the present invention more clearly, but not to limit the protection scope of the present invention.

本发明实施例提供了一种波束赋形方法，应用于双波束通信系统中，该通信系统中的基站采用两个波束为小区内的用户服务，如图1所示，该方法包括：An embodiment of the present invention provides a beamforming method, which is applied to a dual-beam communication system. A base station in the communication system uses two beams to serve users in a cell. As shown in FIG. 1 , the method includes:

步骤101，获取下一个时隙服务所要服务的各个用户的位置信息。Step 101, acquiring location information of each user to be served by the next time slot service.

步骤102，根据获取到的位置信息选择各个用户的总吞吐量相对于下倾角组合（β₁，β₂）的总吞吐量函数β1和β2分别表示第1个波束和第2个波束的下倾角，R_i(β₁,β₂)为第i个用户对应的吞吐量相对于下倾角组合（β₁，β₂）的函数，I为两个波束服务的用户的个数。Step 102, according to the obtained location information, select the total throughput function of the total throughput of each user relative to the combination of downtilt angles (β ₁ , β ₂ ) β1 and β2 represent the downtilt angles of the first beam and the second beam respectively, and R _i (β ₁ , β ₂ ) is the function of the throughput corresponding to the i-th user relative to the combination of downtilt angles (β ₁ , β ₂ ) , I is the number of users served by the two beams.

步骤103，采用DIRECT算法计算使最大的下倾角组合（β_1M，β_2M）。Step 103, using the DIRECT algorithm to calculate Maximum downtilt combination (β _1M , β _2M ).

步骤104，将两个波束的下倾角对应的调整为β_1M，β_2M。Step 104, correspondingly adjust the downtilt angles of the two beams to β _1M and β _2M .

本发明实施例中，获取用户的位置信息，并根据用户的位置信息确定各个用户的总吞吐量相对于下倾角组合的吞吐量函数，并采用DIRECT算法估算使吞吐量函数取最大值的下倾角组合，之后根据计算得到的下倾角组合调整两个波束的下倾角。本发明提供的技术方案，能够提高系统的吞吐量。In the embodiment of the present invention, the user's location information is obtained, and according to the user's location information, the throughput function of the total throughput of each user relative to the combination of downtilt angles is determined, and the DIRECT algorithm is used to estimate the downtilt angle at which the throughput function takes the maximum value combination, and then adjust the downtilt angles of the two beams according to the calculated downtilt angle combination. The technical scheme provided by the invention can improve the throughput of the system.

优选的，上述步骤102具体包括：Preferably, the above step 102 specifically includes:

$R R (({γ γ}_{11},, {γ γ}_{22},, M m)) = = {E E.}_{X x} [[{log log}_{22} ((11 + + X x))]] = = {log log}_{22} ((e e)) {Σ Σ}_{i i = = 00}^{M m - - 11} {Σ Σ}_{l l = = 00}^{i i} \frac{{γ γ}_{11}^{l l + + 11 - - i i}}{{γ γ}_{22} ((i i - - l l))!!} \cdot \cdot {I I}_{11} ((\frac{11}{{γ γ}_{11}},, \frac{{γ γ}_{11}}{{γ γ}_{22}},, i i,, l l + + 11))$

其中I₁(a,b,m,n)为积分表达式where I ₁ (a,b,m,n) is an integral expression

${I I}_{11} ((a a,, b b,, m m,, n no)) = = {Σ Σ}_{i i = = 11}^{n no} \frac{{((- - 11))}^{i i - - 11}}{{((11 - - b b))}^{i i}} \cdot \cdot {I I}_{22} ((a a,, b b,, m m,, n no - - i i + + 11)) + + \frac{{I I}_{22} ((a a,, 11,, m m,, 11))}{{((b b - - 11))}^{n no}};;$

其中，为第i个用户对第s个波束的接收功率，G_si(β_s)表示第i个用户对第s个波束的接收增益相对于第s个波束的下倾角β_s的函数。通过这种方式，能够降低计算下倾角组合（β₁，β₂）的复杂度。in, is the received power of the i-th user to the s-th beam, and G _si (β _s ) represents the function of the i-th user’s reception gain to the s-th beam relative to the downtilt angle β _s of the s-th beam. In this way, the complexity of calculating the combination of downtilt angles (β ₁ , β ₂ ) can be reduced.

其中，任意一个第i个用户对第s个波束的接收增益Among them, the receiving gain of any i-th user to the s-th beam

下面结合具体应用场景对本发明实施例提供的波束赋形方法的步骤和原理进行详细说明，实际应用中，波束下倾的方式包括两种，一种为基于用户为下倾；另一种为基于垂直域的下倾，下面分别对在两种下倾方式下的波束赋形方法的步骤和原理进行详细说明。The steps and principle of the beamforming method provided by the embodiment of the present invention will be described in detail below in combination with specific application scenarios. For the downtilt in the vertical domain, the steps and principles of the beamforming method in the two downtilt modes will be described in detail below.

一、基于用户的下倾1. User-based downslope

如图2所示，为本发明是实施例提供的波束赋形方法的一种应用场景，假设基站将发射天线分为两组，每个天线组有4根发射天线，这两组天线同时发出两个波束，在每个时隙，每个波束仅为一个用户服务。As shown in Figure 2, it is an application scenario of the beamforming method provided by the embodiment of the present invention. It is assumed that the base station divides the transmitting antennas into two groups, and each antenna group has four transmitting antennas, and these two groups of antennas simultaneously transmit Two beams, each serving only one user per time slot.

如图3所示，假设为用户与基站天线连接线在xoy平面上与x轴（天线阵列瞄准轴）的夹角，即用户的方位角；θ为用户与基站天线连接线与水平线的夹角，即用户的俯仰角。由几何计算可得用户i的俯仰角θ_i和方位角为：As shown in Figure 3, suppose is the angle between the connection line between the user and the base station antenna on the xoy plane and the x-axis (the aiming axis of the antenna array), that is, the azimuth angle of the user; θ is the angle between the connection line between the user and the base station antenna and the horizontal line, that is, the pitch angle of the user. The pitch angle θ _i and azimuth angle of user i can be obtained by geometric calculation for:

θ_i＝tan^-1((h_bs-h_i)/d_i)θ _i ＝tan ^-1 ((h _bs -h _i )/d _i )

其中，h_bs为基站天线高度，h_i为用户天线高度，(x_i,y_i)为用户的坐标，d_i为用户到基站的距离，即Among them, h _bs is the height of the base station antenna, h _i is the height of the user antenna, (xi _, y _i ) is the coordinates of the user, d _i is the distance from the user to the base station, that is

${d d}_{i i} = = \sqrt{{x x}_{i i}^{22} + + {y the y}_{i i}^{22}} . .$

设第i个波束的服务用户为i。基站到用户i的天线增益为Let the service user of the i-th beam be i. The antenna gain from base station to user i is

其中，in,

${G G}_{i i,, V V} (({θ θ}_{i i})) = = - - min min [[1212 {((\frac{{θ θ}_{i i} - - {β β}_{i i}}{{θ θ}_{33 dB dB}}))}^{22},, {SLL SLL}_{el el}]];;$

即，Right now,

则两个垂直域内用户的接收信号分别为：Then the received signals of users in the two vertical domains are:

其中：in:

r_i,j表示用户i从其服务波束j接收到的信号；r _i,j denotes the signal received by user i from its serving beam j;

(□)^*表示向量的共轭转置；(□) ^* indicates the conjugate transpose of the vector;

x_i表示波束i到用户i的发送信号，且满足功率约束条件E[|x_i|²]＝1；x _i represents the transmitted signal from beam i to user i, and satisfies the power constraint condition E[| _xi | ² ]=1;

n表示用户i处的复高斯白噪声，服从n～N(0，　1)；n represents the complex white Gaussian noise at user i, obeying n～N(0, 1);

h_i代表用户i和基站之间的n_t×1维信道向量，设信道为瑞利衰落，则h_i,j的元素是独立同分布的随机变量，服从N(0，　1)；h _i represents the n _t ×1-dimensional channel vector between user i and the base station, assuming that the channel is Rayleigh fading, then the elements of h _{i, j} are independent and identically distributed random variables, obeying N(0, 1);

f_i,i是基站波束i对其所服务用户i的预编码向量，它是归一化的，满足f_i,i ²＝1；f _i,i is the precoding vector of base station beam i to user i served by it, which is normalized and satisfies f _i,i ² =1;

P_i ^r表示用户的接收功率，本发明采用的路径损耗模型为P _i ^r represents the received power of the user, and the path loss model adopted by the present invention is

P_i ^r＝P₀(D₀/d_i)^α P _i ^r =P ₀ (D ₀ /d _i ) ^α

其中，P₀是用户距基站的距离为D₀时的接收功率，也称参考功率，d_i是用户和基站之间的距离，本发明中设D₀＝R，则P₀表示用户在小区边缘时的接收功率。本发明假设从基站发出的两个波束的功率相等；Wherein, P ₀ is the received power when the distance between the user and the base station is D ₀ , also known as reference power, _d is the distance between the user and the base station, and D ₀ =R is established in the present invention, then P ₀ represents that the user is in the cell Received power at the edge. The present invention assumes that the powers of the two beams sent from the base station are equal;

式中第一项表示用户i期望的接收信号，第二项表示其他垂直区波束对用户的干扰，第三项表示表示用户i处的归一化加性高斯白噪声。In the formula, the first term represents the received signal expected by user i, the second term represents the interference of other vertical area beams to the user, and the third term represents the normalized additive white Gaussian noise at user i.

则用户的信干噪比表达式为Then the user's signal-to-interference-noise ratio expression is

则用户的吞吐量为Then the user throughput is

R₁＝E[log₂(1+SINR(β₁,β₂))]R ₁ ＝E[log ₂ (1+SINR(β ₁ ,β ₂ ))]

两个用户总吞吐量为The total throughput of two users is

R＝R₁+R₂ R＝R ₁ +R ₂

本发明的目的是要找出最优的组合使得两个用户的吞吐量最大。The purpose of the present invention is to find the optimal combination to maximize the throughput of the two users.

设f_i,i与信道矩阵h_i不相关，则有其中表示自由度为n的卡方分布。Suppose f _i,i is not correlated with channel matrix h _i , then we have in Represents a chi-square distribution with n degrees of freedom.

令make

$X x = = \frac{{γ γ}_{11} Z Z}{11 + + {γ γ}_{22} Y Y}$

其中随机变量且相互独立。则有where the random variable and independent of each other. then there is

${I I}_{11} ((a a,, b b,, m m,, n no)) = = {Σ Σ}_{i i = = 11}^{n no} \frac{{((- - 11))}^{i i - - 11}}{{((11 - - b b))}^{i i}} \cdot \cdot {I I}_{22} ((a a,, b b,, m m,, n no - - i i + + 11)) + + \frac{{I I}_{22} ((a a,, 11,, m m,, 11))}{{((b b - - 11))}^{n no}}$

${I I}_{22} ((a a,, b b,, m m,, n no)) = = {&Integral; &Integral;}_{00}^{\infty \infty} \frac{{x x}^{m m} {e e}^{- - ax ax}}{{((x x + + b b))}^{i i}} dx dx = = {e e}^{ab ab} {Σ Σ}_{i i = = 00}^{m m} (\begin{matrix} m m \\ i i \end{matrix}) {((- - b b))}^{m m - - i i} {I I}_{33} ((a a,, b b,, i i - - n no))$

则系统总吞吐量可表示为Then the total throughput of the system can be expressed as

R＝R₁+R₂＝R₁(P₁ ^rG₁(φ₁,θ₁),P₁ ^rG₂(φ₁,θ₁),1)+R₁(P₂ ^rG₂(φ₂,θ₂),P₂ ^rG₁(φ₂,θ₂),1)R＝R ₁ +R ₂ ＝R ₁ (P ₁ ^r G ₁ (φ ₁ ,θ ₁ ),P ₁ ^r G ₂ (φ ₁ ,θ ₁ ),1)+R ₁ (P ₂ ^r G ₂ (φ ₂ ,θ ₂ ),P ₂ ^r G ₁ (φ ₂ ,θ ₂ ),1)

当β₁、β₂满足约束条件0°≤β₂≤β₁≤90°时，对每一对已知位置的用户，求出最优的(β₁,β₂)组合使得两个用户的吞吐量最大。When β ₁ and β ₂ satisfy the constraints 0°≤β ₂ ≤β ₁ ≤90°, for each pair of users with known positions, find the optimal (β ₁ , β ₂ ) combination so that the two users’ Maximum throughput.

则本发明需要解决的问题为：根据当前被服务用户的位置信息，为基站发出的每个波束选择最佳下倾角使得所有用户的和速率最大，即解决以下问题：Then the problem to be solved in the present invention is: according to the position information of the currently served user, select the best downtilt angle for each beam sent by the base station so that the sum rate of all users is the largest, that is, solve the following problems:

$(({β β}^{* *})) = = arg arg \underset{{β β}_{min min} < < β β < < {β β}_{max max}}{max max} {Σ Σ}_{s the s = = 11}^{S S} {R R}_{s the s} (({β β}_{s the s}))$

其中β_min和β_max分别为最小和最大下倾角组合。本发明采用Dividing RECTangle（DIRECT）算法来求解此问题，该算法被认为是求解带有简单约束条件的连续性最优化问题的有效方法。DIRECT算法不需要知道目标函数的先验信息，非常适合求解类似本发明情况下的复杂目标函数。该算法将函数变量域视作超矩形，对其进行空间分割得到更小的超矩形。用每个超矩形的中心代表该超矩形，目标函数将仅在这些中心点上被计算，计算复杂度被降低。此外，DIRECT在每次迭代中仅选择潜在最优的超矩形进行下一步迭代，加快了收敛速度。该算法通过将将函数变量域不断分割，最终使目标函数即小区吞吐量在某确定点的值最大。Where β _min and β _max are the combination of the minimum and maximum downtilt angles, respectively. The present invention uses the Dividing RECTangle (DIRECT) algorithm to solve this problem, which is considered to be an effective method for solving continuous optimization problems with simple constraints. The DIRECT algorithm does not need to know the prior information of the objective function, and is very suitable for solving complex objective functions similar to the situation of the present invention. The algorithm regards the function variable domain as a hyper-rectangle, and divides it into smaller hyper-rectangles. By using the center of each hyper-rectangle to represent the hyper-rectangle, the objective function will only be calculated on these center points, and the computational complexity is reduced. In addition, DIRECT only selects the potentially optimal hyperrectangle for the next iteration in each iteration, which speeds up the convergence. The algorithm continuously divides the function variable domain, and finally makes the objective function, that is, the cell throughput, the maximum value at a certain point.

二、基于垂直域的下倾2. Decline based on vertical domain

基于垂直域天线下倾与基于用户天线下倾的不同之处在于后者的下倾角是不断变化的，在每个时隙随着所服务用户的不同而不断改变下倾角，而前者的下倾角在一段时间内是基本不变的，各自为其区域内的多个用户服务。基于垂直域的天线下倾研究基于以下假设：基站将发射天线分为两组，每个天线组有4根发射天线，这两组天线同时发出两个波束，为扇区内多个用户服务。根据用户位置，选择每个波束的最佳下倾角。两组天线的下倾角确定后，我们将一组天线服务的用户区域称作一个垂直域。The difference between antenna downtilt based on vertical domain and antenna downtilt based on user is that the downtilt angle of the latter is constantly changing. In each time slot, the downtilt angle is constantly changing according to the different users served, while the downtilt angle of the former is They are basically constant over a period of time, each serving multiple users within its area. The antenna downtilt research based on the vertical domain is based on the following assumptions: the base station divides the transmitting antennas into two groups, and each antenna group has four transmitting antennas, and these two groups of antennas emit two beams at the same time to serve multiple users in the sector. Depending on the user location, the optimal downtilt for each beam is selected. After the downtilt angles of the two sets of antennas are determined, we call the user area served by one set of antennas a vertical domain.

采用3GPP天线模型和小区配置，本发明所用参数配置可如如下表1所示：Adopt 3GPP antenna model and cell configuration, the parameter configuration used in the present invention can be as shown in table 1 below:

表1Table 1

设扇区被分为2个垂直域，用户在扇区内均匀分布。如表1所示，设蜂窝小区半径为500m，基站采用三扇区模型，扇区被分为两个环形有效垂直域（Vertical Region）VS1、VS2。Suppose the sector is divided into two vertical domains, and the users are evenly distributed in the sector. As shown in Table 1, assume that the cell radius is 500m, the base station adopts a three-sector model, and the sector is divided into two ring-shaped effective vertical regions (Vertical Region) VS1 and VS2.

天线下倾角过大，水平方向的传播特性图将变成扁平，尤其当天线下倾角超过20°，会出现豁口及副瓣，增加对同频小区的干扰。根据文献所知，天线的最大下倾角不能超过24°。If the downtilt angle of the antenna is too large, the propagation characteristic diagram in the horizontal direction will become flat. Especially when the downtilt angle of the antenna exceeds 20°, there will be gaps and side lobes, which will increase the interference to the same frequency cell. According to the literature, the maximum downtilt angle of the antenna cannot exceed 24°.

在扇区内均匀撒100个用户，根据用户到两个波束的接收信号的SINR来决定用户由哪个波束服务。以某一用户为例，由前面所述可知，当分别采用波束1、2作为用户的服务波束时，用户收到的信号可分别表示为：Evenly distribute 100 users in the sector, and determine which beam serves the user according to the SINR of the received signals from the users to the two beams. Taking a certain user as an example, it can be seen from the foregoing that when beams 1 and 2 are respectively used as the user’s service beams, the signals received by the user can be expressed as:

比较其大小，本发明选择SINR大的波束作为用户的服务波束。由于f_i,i与信道矩阵h_i不相关，因此有即服从自由度为2的卡方分布。Comparing their sizes, the present invention selects a beam with a large SINR as a serving beam for a user. Since f _i,i is uncorrelated with the channel matrix h _i , there is That is, it obeys a chi-square distribution with 2 degrees of freedom.

垂直域的吞吐量为The throughput of the vertical domain is

${R R}_{s the s} = = {Σ Σ}_{i i = = 11}^{i i = = {K K}_{s the s}} E E. [[{log log}_{22} ((11 + + S S {INR INR}_{i i,, s the s} ((β β))))]]$

扇区总吞吐量为The total sector throughput is

$R R = = {Σ Σ}_{s the s = = 11}^{S S} {R R}_{s the s} = = {Σ Σ}_{s the s = = 11}^{S S} {Σ Σ}_{k k = = 11}^{k k = = {K K}_{s the s}} E E. [[{log log}_{22} ((11 + + {SINR SINR}_{i i,, s the s} ((β β))))]]$

求解此问题的方法同基于用户的下倾问题的求解方法。解出最佳β后，按照两个波束的服务用户及用户位置，可自然地将扇区分为两个垂直域。The method of solving this problem is the same as that of the user-based downdip problem. After solving the optimal β, according to the service users and user positions of the two beams, the sector can be naturally divided into two vertical domains.

基于同样的构思，本发明实施例还提供了一种波束赋形设备，作为基站应用于无线通信系统中，如图4所示，该设备包括：Based on the same idea, an embodiment of the present invention also provides a beamforming device, which is used as a base station in a wireless communication system. As shown in FIG. 4, the device includes:

位置信息获取模块401，用于获取下一个时隙服务所要服务的各个用户的位置信息；A location information acquisition module 401, configured to acquire the location information of each user to be served by the next time slot service;

函数调用模块402，用于根据位置信息获取模块401获取到的位置信息选择各个用户的总吞吐量相对于下倾角组合（β₁，β₂）的总吞吐量函数β1和β2分别表示第1个波束和第2个波束的下倾角，R_i(β₁,β₂)为第i个用户对应的吞吐量相对于下倾角组合（β₁，β₂）的函数，I为两个波束服务的用户的个数。The function calling module 402 is used to select the total throughput function of the total throughput of each user relative to the combination of downtilt angles (β ₁ , β ₂ ) according to the location information acquired by the location information acquisition module 401 β1 and β2 represent the downtilt angles of the first beam and the second beam respectively, and R _i (β ₁ , β ₂ ) is the function of the throughput corresponding to the i-th user relative to the combination of downtilt angles (β ₁ , β ₂ ) , I is the number of users served by the two beams.

计算模块403，用于采用DIRECT算法计算使最大的下倾角组合（β_1M，β_2M）。Calculation module 403, used to calculate using DIRECT algorithm Maximum downtilt combination (β _1M , β _2M ).

赋形模块404，用于将两个波束的下倾角对应的调整为β_1M，β_2M。The shaping module 404 is configured to correspondingly adjust the downtilt angles of the two beams to β _1M and β _2M .

优选的，函数调用模块402具体用于根据获取到的位置信息确定每一个用户接收各个波束的信号强度相对于下倾角组合（β₁，β₂）的函数，并取作为各个用户的总吞吐量相对于下倾角组合（β₁，β₂）的总吞吐量函数其中，Preferably, the function calling module 402 is specifically configured to determine the function of the signal strength of each user receiving each beam relative to the combination of downtilt angles (β ₁ , β ₂ ) according to the acquired position information, and take As a function of aggregate throughput for individual users with respect to the downtilt combination (β ₁ , β ₂ ) in,

以上所述仅是本发明的优选实施方式，应当指出，对于本技术领域的普通技术人员来说，在不脱离本发明技术原理的前提下，还可以做出若干改进和润饰，这些改进和润饰也应视为本发明的保护范围。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 technical principle of the present invention, some improvements and modifications can also be made. These improvements and modifications It should also be regarded as the protection scope of the present invention.

Claims

1. A beamforming method applied to a dual-beam communication system, the method comprising:

acquiring the position information of each user to be served by the current time slot;

selecting a combination (beta) of the total throughput of each user with respect to the downtilt angle according to the acquired location information₁，β₂) Total throughput function ofBeta 1 and beta 2 minutesRespectively, the downtilt angles, R, of the 1 st and 2 nd beams_i(β₁,β₂) Throughput versus downtilt combination (β) for the ith user₁，β₂) I is the number of users served by the two beams;

computing using a DIRECT algorithmMaximum down dip angle combination (beta)_1M，β_2M）；

Correspondingly adjusting the downtilt angles of the two beams to beta_1M，β_2M。

2. The method of claim 1, wherein selecting a combination of total throughput versus downtilt (β) for each user based on the obtained location information₁，β₂) Total throughput function ofThe method specifically comprises the following steps:

for each user, the received power of each beam is calculated, and the receiving gain of each beam is combined with the declination angle (beta)₁，β₂) A function of (a);

getAs a combination of total throughput versus downtilt (β) for each user₁，β₂) Total throughput function ofWherein,

wherein I₁(a, b, m, n) is an integral expression, and

<math> <mrow> <msub> <mi>I</mi> <mn>2</mn> </msub> <mrow> <mo>(</mo> <mi>a</mi> <mo>,</mo> <mi>b</mi> <mo>,</mo> <mi>m</mi> <mo>,</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>=</mo> <munderover> <mo>&Integral;</mo> <mn>0</mn> <mo>∞</mo> </munderover> <mfrac> <mrow> <msup> <mi>x</mi> <mi>m</mi> </msup> <msup> <mi>e</mi> <mrow> <mo>-</mo> <mi>ax</mi> </mrow> </msup> </mrow> <msup> <mrow> <mo>(</mo> <mi>x</mi> <mo>+</mo> <mi>b</mi> <mo>)</mo> </mrow> <mi>i</mi> </msup> </mfrac> <mi>dx</mi> <mo>=</mo> <msup> <mi>e</mi> <mi>ab</mi> </msup> <munderover> <mi>Σ</mi> <mrow> <mi>i</mi> <mo>=</mo> <mn>0</mn> </mrow> <mi>m</mi> </munderover> <mfenced open='(' close=')'> <mtable> <mtr> <mtd> <mi>m</mi> </mtd> </mtr> <mtr> <mtd> <mi>i</mi> </mtd> </mtr> </mtable> </mfenced> <msup> <mrow> <mo>(</mo> <mo>-</mo> <mi>b</mi> <mo>)</mo> </mrow> <mrow> <mi>m</mi> <mo>-</mo> <mi>i</mi> </mrow> </msup> <msub> <mi>I</mi> <mn>3</mn> </msub> <mrow> <mo>(</mo> <mi>a</mi> <mo>,</mo> <mi>b</mi> <mo>,</mo> <mi>i</mi> <mo>-</mo> <mi>n</mi> <mo>)</mo> </mrow> <mo>;</mo> </mrow> </math>

<math> <mrow> <msub> <mi>I</mi> <mn>3</mn> </msub> <mrow> <mo>(</mo> <mi>a</mi> <mo>,</mo> <mi>b</mi> <mo>,</mo> <mi>m</mi> <mo>)</mo> </mrow> <mo>=</mo> <munderover> <mo>&Integral;</mo> <mi>b</mi> <mo>∞</mo> </munderover> <msup> <mi>x</mi> <mi>m</mi> </msup> <msup> <mi>e</mi> <mrow> <mo>-</mo> <mi>ax</mi> </mrow> </msup> <mi>dx</mi> <mo>=</mo> <mfenced open='{' close=''> <mtable> <mtr> <mtd> <msup> <mi>e</mi> <mrow> <mo>-</mo> <mi>ab</mi> </mrow> </msup> <munderover> <mi>Σ</mi> <mrow> <mi>i</mi> <mo>=</mo> <mn>0</mn> </mrow> <mi>m</mi> </munderover> <mfrac> <mrow> <mi>m</mi> <mo>!</mo> </mrow> <mrow> <mi>i</mi> <mo>!</mo> </mrow> </mfrac> <mfrac> <msup> <mi>b</mi> <mi>i</mi> </msup> <msup> <mi>a</mi> <mrow> <mi>m</mi> <mo>-</mo> <mi>i</mi> <mo>+</mo> <mn>1</mn> </mrow> </msup> </mfrac> </mtd> <mtd> <mi>m</mi> <mo>&GreaterEqual;</mo> <mn>0</mn> </mtd> </mtr> <mtr> <mtd> <msub> <mi>E</mi> <mn>1</mn> </msub> <mrow> <mo>(</mo> <mi>ab</mi> <mo>)</mo> </mrow> </mtd> <mtd> <mi>m</mi> <mo>=</mo> <mo>-</mo> <mn>1</mn> </mtd> </mtr> <mtr> <mtd> <mfrac> <mrow> <msub> <mi>E</mi> <mn>1</mn> </msub> <mrow> <mo>(</mo> <mi>ab</mi> <mo>)</mo> </mrow> </mrow> <mrow> <msup> <mrow> <mo>(</mo> <mo>-</mo> <mi>a</mi> <mo>)</mo> </mrow> <mrow> <mo>-</mo> <mi>m</mi> <mo>-</mo> <mn>1</mn> </mrow> </msup> <mrow> <mo>(</mo> <mo>-</mo> <mi>m</mi> <mo>-</mo> <mn>1</mn> <mo>)</mo> </mrow> <mo>!</mo> </mrow> </mfrac> <mo>+</mo> <mfrac> <msup> <mi>e</mi> <mrow> <mo>-</mo> <mi>ab</mi> </mrow> </msup> <msup> <mi>b</mi> <mrow> <mo>-</mo> <mi>m</mi> <mo>-</mo> <mn>1</mn> </mrow> </msup> </mfrac> <munderover> <mi>Σ</mi> <mrow> <mi>i</mi> <mo>=</mo> <mn>0</mn> </mrow> <mrow> <mo>-</mo> <mi>m</mi> <mo>-</mo> <mn>2</mn> </mrow> </munderover> <mfrac> <mrow> <msup> <mrow> <mo>(</mo> <mo>-</mo> <mi>ab</mi> <mo>)</mo> </mrow> <mi>i</mi> </msup> <mrow> <mo>(</mo> <mo>-</mo> <mi>m</mi> <mo>-</mo> <mi>i</mi> <mo>-</mo> <mn>2</mn> <mo>)</mo> </mrow> <mo>!</mo> </mrow> <mrow> <mrow> <mo>(</mo> <mo>-</mo> <mi>m</mi> <mo>-</mo> <mn>1</mn> <mo>)</mo> </mrow> <mo>!</mo> </mrow> </mfrac> </mtd> <mtd> <mi>m</mi> <mo>≤</mo> <mo>-</mo> <mn>2</mn> </mtd> </mtr> </mtable> </mfenced> </mrow> </math>

wherein,received power of s beam for i user, G_si(β_s) Represents the downtilt angle beta of the reception gain of the ith user to the s beam relative to the s beam_sAs a function of (c).

3. The method of claim 2, wherein for each user, its receive gain versus downtilt combination (β) for each beam is calculated separately₁，β₂) Comprises:

calculating the receiving gain G of the ith user to the s beam by the following formula_si(β_s)：

Wherein,and theta_iAzimuth angle and pitch angle corresponding to the ith user, SLLaz and SLLel are side lobe levels of horizontal and vertical directional diagrams, SLL_totIs the total side-lobe level of the signal,for the received power of the ith user on the s-th beam,is the angle between the aiming axis of the antenna array of the base station where the ith user is located and the x axis.

4. A beamforming apparatus for use in a wireless communication system as a base station, the apparatus comprising:

the system comprises a position information acquisition module, a position information acquisition module and a time slot processing module, wherein the position information acquisition module is used for acquiring the position information of each user to be served by the next time slot service;

a function calling module for selecting the total throughput of each user relative to the downward inclination angle combination (beta) according to the position information acquired by the position information acquisition module₁，β₂) Total throughput function ofβ 1 and β 2 denote downtilt angles of the 1 st and 2 nd beams, respectively, R_i(β₁,β₂) Throughput versus downtilt combination (β) for the ith user₁，β₂) I is the number of users served by the two beams;

a calculation module for calculating the equation using the DIRECT algorithmMaximum down dip angle combination (beta)_1M，β_2M）；

A shaping module for correspondingly adjusting the downtilt angles of the two beams to beta_1M，β_2M。

5. The device of claim 4, wherein the function call module is specifically configured to determine, according to the obtained location information, a combination (β) of signal strength of each user receiving each beam with respect to downtilt angle₁，β₂) Is taken as a function ofAs a combination of total throughput versus downtilt (β) for each user₁，β₂) Total throughput function of

Wherein,

wherein I₁(a, b, m, n) is an integral expression, and

6. The device of claim 5, wherein the function call module calculates the reception gain G for the ith user for the ith beam by specifically using the following formula_si(β_s)：

Wherein,and theta_iAzimuth angle and pitch angle, SLL, corresponding to the ith user respectively_azAnd SLL_elSide lobe levels, SLL, of the horizontal and vertical patterns, respectively_totIs the total side-lobe level of the signal,for the received power of the ith user on the s-th beam,is the angle between the aiming axis of the antenna array of the base station where the ith user is located and the x axis.