CN101090286A - Wireless system, base station device and terminal device - Google Patents

Abstract

In ordinary ORBF, numbers of random beams are fixed, and during the process of transmitting signals with random beams, if numbers sent at the same time are increased, then interference appears among them, so quality of signals becomes poor. This invention applies a method of changing the numbers of beams sent by random beams according to the wireless state reported by a terminal so as to maximize capacitance of the system and leading in a MBS algorithm determining beam numbers transmitted in terms of SINR.

Description

Translated fromChinese

无线系统、基站装置及终端装置Wireless system, base station device and terminal device

技术领域technical field

本发明提供一种由无线通信基站装置及终端装置实施的多用户MIMO传输(多输入多输出)中波束形成的方法。特别是，提供一种通过抑制随机波束形成方式中无用的发送而频率利用效率较高的传输方法。The present invention provides a beamforming method in multi-user MIMO transmission (multiple-input multiple-output) implemented by a wireless communication base station device and a terminal device. In particular, a transmission method with high frequency utilization efficiency is provided by suppressing unnecessary transmission in a random beamforming scheme.

背景技术Background technique

目前正在开展有关MIMO(Multi-Input Multi-Output，即多输入多输出)传输的各种研究。在非专利文献1中示出了可以通过基站和终端以1对1方式进行MIMO传输的单用户MIMO来大幅提高频率利用效率的技术。在非专利文献2中介绍了脏纸码(Dirty paper coding，简称DPC)，并且在非专利文献3及4中示出了如果使用DPC，则达到MIMO广播传输的最大容量的技术。但是，因为DPC的计算量的大小，而难以进行安装。因此，在非专利文献5中，介绍了块对角化(Block Diagonalization，简称BD)。在此，基站进行线性空间预编码，对用户间干扰进行迫零(ZeroForcing)。在该背景技术中，众所周知虽然其前提为可以理想地推测信道状态信息(Channel State Information，简称CSI)，但是在实际MIMO的安装过程中，特别是在天线数较多时和用户数较多时却难以进行理想推测。另外，对于发送完整的CSI信息的情况而言，反馈信息量的增加成为课题。在非专利文献6及7中，提出了利用部分CSI的多用户MIMO。但是，对于这些现有技术而言，发送天线数和接收天线数为相同数目，不能认为是适合于蜂窝环境的条件设定。在非专利文献8中，提出了一种只将被称为随机波束形成(Random Beamforming)的信号对干扰噪比(SINR)作为反馈信息的方法。该方法用来使用随机的波束形成，只给最佳传输路径环境的1名用户分配资源。再者，在非专利文献9中，提出了将随机波束形成应用于MIMO中的方案。但是，该方法同时只给唯一一名用户分配资源，是与单用户的MIMO对应的方法。利用正交的随机波束形成的方法(ORBF：Orthogonal Random Beam Forming)，也在非专利文献10中进行了介绍。在ORBF中，各用户向基站报告作为最大SINR的波束指引。可知在ORBF中在用户数较多时达到DPC的最大总容量。但是，在蜂窝系统中，因为一个基站的用户数至多是64名用户左右，所以要考虑，采用ORBF只能得到少许的性能增加。因此，在非专利文献11中，采用了被称为多用户分集和多路复用(Multi-user diversityand multiplexing，MUDAM)的方法来谋求改进。但是，MUDAM在确定全部波束形成向量之前多次需要CSI的反馈，并且如同蜂窝那样，在包含高速移动的用户时，是不适合的。Various researches on MIMO (Multi-Input Multi-Output, that is, multiple input multiple output) transmission are currently being carried out. Non-PatentDocument 1 discloses a technology capable of greatly improving frequency utilization efficiency by single-user MIMO in which a base station and a terminal perform MIMO transmission in a one-to-one manner. Non-PatentDocument 2 introduces Dirty paper coding (DPC for short), andNon-Patent Documents 3 and 4 show techniques to achieve the maximum capacity of MIMO broadcast transmission if DPC is used. However, it is difficult to implement the DPC due to the large amount of calculation. Therefore, inNon-Patent Document 5, Block Diagonalization (BD for short) is introduced. Here, the base station performs linear spatial precoding and performs zero-forcing (ZeroForcing) on inter-user interference. In this background technology, it is well known that although the premise is that the channel state information (Channel State Information, referred to as CSI) can be estimated ideally, it is difficult in the actual MIMO installation process, especially when the number of antennas is large and the number of users is large. Make an ideal guess. Also, when transmitting complete CSI information, an increase in the amount of feedback information becomes a problem. In Non-Patent Documents 6 and 7, multi-user MIMO using partial CSI is proposed. However, in these conventional techniques, the number of transmitting antennas and the number of receiving antennas are the same, which cannot be regarded as a condition setting suitable for a cellular environment. Non-Patent Document 8 proposes a method of using only the signal-to-interference-noise ratio (SINR) called random beamforming (Random Beamforming) as feedback information. This method uses random beamforming to allocate resources to only one user in the optimal transmission path environment. Furthermore, Non-Patent Document 9 proposes applying random beamforming to MIMO. However, this method allocates resources to only one user at the same time, and is a method corresponding to single-user MIMO. A method using orthogonal random beam forming (ORBF: Orthogonal Random Beam Forming) is also introduced in Non-Patent Document 10. In ORBF, each user reports beam steering as the maximum SINR to the base station. It can be seen that the maximum total capacity of DPC is reached when the number of users is large in ORBF. However, in a cellular system, because the number of users in a base station is at most about 64 users, it should be considered that only a small increase in performance can be obtained by using ORBF. Therefore, in Non-Patent Document 11, a method called multi-user diversity and multiplexing (MUDAM) is adopted for improvement. However, MUDAM requires CSI feedback many times before determining all beamforming vectors, and is not suitable when high-speed moving users are included like cellular.

非专利文献1：G.J.Foschini and M.J.Gans，“On limits of wirelesscommunications in a fading environment when using multipleantennas”，Wireless Personal Commun.：Khuwer Academic Press，no.6，pp.311-335，1998.Non-Patent Document 1: G.J.Foschini and M.J.Gans, "On limits of wireless communications in a fading environment when using multiple antennas", Wireless Personal Commun.: Khuwer Academic Press, no.6, pp.311-335, 1998.

非专利文献2：M.Costa，“Writing on Dirty Paper”，IEEE Trans.Inf.Theory，Vol.29，pp.439-441，May 1983.Non-Patent Document 2: M. Costa, "Writing on Dirty Paper", IEEE Trans. Inf. Theory, Vol.29, pp.439-441, May 1983.

非专利文献3：P.Viswanath and D.Tse，“Sum capacity of the VectorGaussian broadcast channel and uplink-downlink duality”，IEEE Trans.Info.Theory，vol.49，pp.1912-1921，Aug.2003.Non-Patent Document 3: P.Viswanath and D.Tse, "Sum capacity of the VectorGaussian broadcast channel and uplink-downlink duality", IEEE Trans.Info.Theory, vol.49, pp.1912-1921, Aug.2003.

非专利文献4：G.Carie and S.Shamai，“On the achievable throuputof a multiantenna Gaussian broadcast channel”，IEEE Trans.Info.Theory，Vol.49，pp.1691-1706，Jul.2003.Non-Patent Document 4: G.Carie and S.Shamai, "On the achievable throuput of a multiantenna Gaussian broadcast channel", IEEE Trans.Info.Theory, Vol.49, pp.1691-1706, Jul.2003.

非专利文献5：Q.H.Spencer，A.L.Swindehurst and M.Haardt，“Zero-forcing Methods for Downlink Spatial Multiplexing inMulti-User MIMO Channels”，IEEE Trans.Sig.Proc.，vol.52，pp.461-471，Feb.2004.Non-Patent Document 5: Q.H.Spencer, A.L.Swindehurst and M.Haardt, "Zero-forcing Methods for Downlink Spatial Multiplexing in Multi-User MIMO Channels", IEEE Trans.Sig.Proc., vol.52, pp.461-471, Feb .2004.

非专利文献6：R.W.Heath Jr.，M.Airy and A.J.Paulraj，”Multiuserdiversity for MIMO wireless systems with linear receivers”，in Proc.Of Asilomar Conf.on Signals，Systems，and Computers，vol.2，pp.1194-1199，Nov.2001.Non-Patent Document 6: R.W.Heath Jr., M.Airy and A.J.Paulraj, "Multiuserdiversity for MIMO wireless systems with linear receivers", in Proc.Of Asilomar Conf.on Signals, Systems, and Computers, vol.2, pp.1194 -1199, Nov. 2001.

非专利文献7：H.Lee，M.Shin and C.Lee，”An eigen-based MIMOmultiuser scheduler with partial feedback information”.IEEE commun.Lett.，vol.9，pp.328-330，Apr.2005.Non-Patent Document 7: H.Lee, M.Shin and C.Lee, "An eigen-based MIMOmultiuser scheduler with partial feedback information". IEEE commun. Lett., vol.9, pp.328-330, Apr.2005.

非专利文献8：P.Viswanath，D.N.C.Tse andR.Laroia，”Opportunistic beamforming using dumb antennas”，IEEETrans.Infom.Theory，vol.48，pp.1277-1294，Jun.2002.Non-Patent Document 8: P.Viswanath, D.N.C.Tse and R.Laroia, "Opportunistic beamforming using dumb antennas", IEEETrans.Infom.Theory, vol.48, pp.1277-1294, Jun.2002.

非专利文献9：J.Chung，C.S.Hwang，K.Kim and Y.K.Kim，”Arandom beamforming technique in MIMO systems exploiting multiuserdiversity”，IEEE J.Select.Areas Commun.，vol.21，pp.848-855，Jun.2003.Non-Patent Document 9: J.Chung, C.S.Hwang, K.Kim and Y.K.Kim, "Arandom beamforming technique in MIMO systems exploiting multiuserdiversity", IEEE J.Select.Areas Commun., vol.21, pp.848-855, Jun .2003.

非专利文献10：M.Sharif and B.Hassibi，“On the capacity of MIMObroadcast channels with partial side information”，IEEE Trans.Info.Theory，vol.51，pp.506-522，Feb.2005.Non-Patent Document 10: M. Sharif and B. Hassibi, "On the capacity of MIMO broadcast channels with partial side information", IEEE Trans.Info.Theory, vol.51, pp.506-522, Feb.2005.

非专利文献11：G.C.Briones，A.A.Dowhuszko，J.Hamalainen andR.Wichiman，“Achievable data rates for two transmit antennabroadcast channels with WCDMA HSDPA feedback information”，Proc.IEEE Int.Conf.Commun.，vol.4，pp.2722-2727，May 2005.Non-Patent Document 11: G.C.Briones, A.A.Dowhuszko, J.Hamalainen and R.Wichiman, "Achievable data rates for two transmit antenna broadcast channels with WCDMA HSDPA feedback information", Proc.IEEE Int.Conf.Commun., vol.4, pp. 2722-2727, May 2005.

发明内容Contents of the invention

在以往的ORBF中，随机波束的数目是固定的值。在随机波束发送过程中，因为若同时发送的波束数有所增加，则在相互的波束间产生干扰，所以发生信号质量的变差。因此，总是使用多个随机波束进行信号发送不牵涉到系统容量的最大化。这是第一课题。In the conventional ORBF, the number of random beams is a fixed value. During random beam transmission, if the number of beams simultaneously transmitted increases, interference occurs between the beams, so that signal quality deteriorates. Therefore, always using multiple random beams for signaling does not involve maximization of system capacity. This is the first subject.

另外，还不清楚应该如何确定同时发送的波束数。这是第二课题。Also, it is not clear how the number of simultaneous beams should be determined. This is the second subject.

为了解决第一课题，采用下述结构，该结构按照终端报告的无线状况，令通过随机波束发送的波束数产生变化，以使系统容量最大化。具体而言，使终端对基站报告随机波束中SINR(Signal to Interference andNoise Rate：信号对干扰噪声比，S/(I+N))最高的波束的识别符、和该波束的SINR。在基站中设置波束数确定单元，用来根据所报告的信息，求出系统容量成为最大的发送波束数。通过波束数确定单元，来确定发送的波束数及波束、以及使用该波束发送信息的作为对方的终端(目标终端)。该发送波束数确定是以无线帧单位或多个无线帧单位来进行的。In order to solve the first problem, a configuration is adopted in which the number of beams transmitted by random beams is changed in accordance with the radio status reported by the terminal to maximize the system capacity. Specifically, the terminal reports to the base station the identifier of the beam with the highest SINR (Signal to Interference and Noise Rate: Signal to Interference and Noise Ratio, S/(I+N)) among the random beams and the SINR of the beam. A beam number determination unit is provided in the base station to obtain the number of transmission beams at which the system capacity becomes the maximum based on the reported information. The number of beams to be transmitted, the number of beams to be transmitted, and a terminal (target terminal) to transmit information using the beams are determined by the beam number determining unit. The determination of the number of transmission beams is performed in units of radio frames or units of radio frames.

为了解决第二课题，导入根据SINR确定发送波束数的MBS(MultiBeam Selection，根据从终端所报告的SINR选择发送的波束数及波束的方法)算法。在SNR(Signal to Noise Rate，即信噪比)较低时，干扰不为决定信号质量的决定因素，而如果同时发送多个波束，则系统容量增加。另一方面，在SNR较高时，因为干扰成为决定因素，所以并不发送多个波束，而进行利用1个波束的发送。在终端有多个天线的MIMO环境下，包括天线在内进行1个数据流的传输。这样，通过采用MBS算法来确定发送波束数，就可以适当决定波束数，课题得以解决。In order to solve the second problem, an MBS (MultiBeam Selection, a method of selecting the number of beams to transmit and the method of beam selection based on the SINR reported from the terminal) algorithm that determines the number of transmission beams based on the SINR is introduced. When the SNR (Signal to Noise Rate, signal-to-noise ratio) is low, interference is not a decisive factor in determining signal quality, and if multiple beams are sent at the same time, the system capacity increases. On the other hand, when the SNR is high, since interference becomes a determining factor, transmission is performed using one beam instead of multiple beams. In a MIMO environment where a terminal has multiple antennas, one data stream is transmitted including the antennas. Thus, by determining the number of transmission beams using the MBS algorithm, the number of beams can be appropriately determined, and the problem can be solved.

发明效果Invention effect

根据本发明，可以将以往因为变更发送波束数的过程不清楚而不能实施的随机波束的发送波束数总是能够保持为最佳状态，并且能够维持将系统容量保持为最大的状态。因而，课题得以解决。According to the present invention, the number of transmission beams of random beams, which cannot be performed conventionally because the procedure of changing the number of transmission beams is unclear, can always be kept at an optimum state, and the state of maintaining the system capacity at the maximum can be maintained. Thus, the problem was solved.

附图说明Description of drawings

图1是包括本发明实施示例的基站装置和终端装置的无线系统的图。FIG. 1 is a diagram of a wireless system including a base station device and a terminal device of an embodiment example of the present invention.

图2是表示本发明实施示例的基站装置和终端装置之间的顺序的图。FIG. 2 is a diagram showing a sequence between a base station device and a terminal device according to an embodiment example of the present invention.

图3是表示本发明实施示例的随机波束形成的发送方法的图。FIG. 3 is a diagram illustrating a random beamforming transmission method according to an embodiment example of the present invention.

图4是本发明实施示例的基站装置的结构图。Fig. 4 is a structural diagram of a base station device of an embodiment example of the present invention.

图5是本发明实施示例的终端装置的结构图。FIG. 5 is a structural diagram of a terminal device in an embodiment example of the present invention.

其中，in,

1...  基站装置1... base station device

2...  MIMO信道2... MIMO channels

3...  终端装置3... terminal device

4...  基站天线4... base station antenna

5...  终端天线5... terminal antenna

101...  网络接口101... network interface

102...  调制单元102... modulation unit

103...  权重乘法单元103... weight multiplication unit

104...  导频信号生成单元104... Pilot signal generation unit

105...  空间调制单元105... Spatial modulation unit

106...  信号合成单元106... Signal synthesis unit

107...  双工器107... duplexer

108...  解调单元108... Demodulation unit

109...  资源管理器109... Explorer

301...  双工器301... duplexer

302...  解调单元302... Demodulation unit

303...  资源管理器303... Explorer

304...  网络接口304... network interface

305...  调制单元305... modulation unit

具体实施方式Detailed ways

采用图1～5来说明本发明的第1实施示例。图1表示的是本专利假定的蜂窝环境下MIMO(Multi-Input Multi-Output)传输的结构示例。基站方具备m_t根天线，终端方分别具备m_r根天线。传输路径2成为MIMO信道，并且各个天线接受独立的衰落。从基站发送的信号利用由m_t×m_t构成的随机合成整体波束形成矩阵(Random complex unitary beamformingmatrix)，进行随机波束形成。假设，用户数为K，则在蜂窝环境下一般存在K＞m_t＞m_r的关系。在以往的技术中，虽然存在发送波束数m_b＝m_t的关系，但是在根据本专利构成的实施示例中，大多数情况下成立m_b＜m_t的关系。只是在各终端的平均SNR较低时，成立m_b＝m_t的关系。A first example of implementation of the present invention will be described using FIGS. 1 to 5 . FIG. 1 shows a structural example of MIMO (Multi-Input Multi-Output) transmission in a cellular environment assumed in this patent. The base station side has m_t antennas, and the terminal side has m_r antennas respectively.Transmission path 2 becomes a MIMO channel, and each antenna receives independent fading. The signal transmitted from the base station is subjected to random beamforming using a random complex unitary beamforming matrix (Random complex unitary beamforming matrix) composed of m_t ×m_t . Assuming that the number of users is K, there is generally a relationship of K>m_t >m_r in a cellular environment. In the conventional technology, although there is a relationship of the number of transmission beams m_b =m_t , in the implementation example constructed according to this patent, the relationship of m_b <m_t is established in most cases. Only when the average SNR of each terminal is low, the relationship of m_b =m_t holds.

下面，为了评价根据本发明构成的实施示例的性能，将导出理论公式。把由从发送天线i到接收天线j的传输信道构成的MIMO信道，表述为In the following, theoretical formulas will be derived in order to evaluate the performance of the embodiment examples constructed according to the present invention. Express the MIMO channel formed by the transmission channel from transmit antenna i to receive antenna j as

H_k＝{h_ij(k)}_mr×mt    (公式1)H_k ={h_ij (k)}_mr×mt (Formula 1)

将从发送天线号i到用户k之接收天线号j的传输信道h_ij(k)假定为复合高斯随机信道。发送机使用由m_b的相互正交的随机矢量_m构成的阵列权重进行波束形成。用户k的接收信号y_k用The transmission channel h_ij (k) from transmitting antenna number i to receiving antenna number j of user k is assumed to be a composite Gaussian random channel. The transmitter performs beamforming using an array of weights consisting of mutually orthogonal random vectors _m of m_b . The received signal y_k of user k is used

(公式2)

(Formula 2)

来表述。这里，s_m代表第m个发送信号。假设发送波束的功率为等分布，则成为to express. Here, s_m represents the mth transmitted signal. Assuming that the power of the transmit beams is equally distributed, then becomes

$E\left[s_m^{*}{s}_m\right]=\frac{{\mathrm{\&rho;}}_0}{m_b}(1\&le;m{\&le;m}_b)$(公式3)$\mathrm{E.}\left[{\mathrm{the\; s}}_m^{*}{\mathrm{the\; s}}_m\right]=\frac{{\mathrm{\&rho;}}_0}{m_b}(1\&le;m{\&le;m}_b)$ (Formula 3)

这里，ρ₀表示平均SNR。首先，考虑m_r＝1的情形。若假定完整的CSI(Channel State Information，即信道状态信息)，则终端k可以计算第m个波束的SINR，并且为Here,_ρ0 represents the average SNR. First, consider the case where m_r =1. Assuming complete CSI (Channel State Information, that is, channel state information), terminal k can calculate the SINR of the mth beam, and is

(公式4) (Formula 4)

假设，全部终端报告所接收到的波束中最高的SINR，并且基站从其中选择SINR最高的m_b终端来进行了波束发送，则系统容量可以和Assuming that all terminals report the highest SINR in the received beams, and the base station selects the m_b terminal with the highest SINR to transmit the beam, the system capacity can be compared with

$\mathrm{<span><span>R</span>R</span>}<span><span>(</span>(</span>{\mathrm{<span><span>m</span>m</span>}}_{\mathrm{<span><span>b</span>b</span>}}<span><span>)</span>)</span><span><span>\&ap;</span>\&ap;</span>\mathrm{<span><span>E</span>E.</span>}<span><span>[</span>[</span>\underset{\mathrm{<span><span>i</span>i</span>}<span><span>=</span>=</span>\mathrm{<span><span>1</span>1</span>}}{\overset{{\mathrm{<span><span>m</span>m</span>}}_{\mathrm{<span><span>b</span>b</span>}}}{\mathrm{<span><span>\&Sigma;</span>\&Sigma;</span>}}}\mathrm{<span><span>log</span>log</span>}<span><span>(</span>(</span>\mathrm{<span><span>1</span>1</span>}<span><span>+</span>+</span>\underset{\mathrm{<span><span>1</span>1</span>}<span><span>\&le;</span>\&le;</span>\mathrm{<span><span>k</span>k</span>}<span><span>\&le;</span>\&le;</span>\mathrm{<span><span>K</span>K</span>}}{\mathrm{<span><span>max</span><figure-callout\; label="max"\; filenames="A20061009176300161.png,A20061009176300171.png"\; state="\{\{state\}\}">max</figure-callout></span>}}{\mathrm{<span><span>SINR</span>SINR</span>}}_{\mathrm{<span><span>ki</span>the\; ki</span>}}<span><span>)</span>)</span><span><span>]</span>]</span>$

$=m_{b}E\left[\log (1+\underset{1\&le;k\&le;K}{\max }{\mathrm{SINR}}_{\mathrm{ki}})\right]$(公式5)$=m_b\mathrm{E.}\left[\log (1+\underset{1\&le;k\&le;K}{\mathrm{<figure-callout\; label="max"\; filenames="A20061009176300161.png,A20061009176300171.png"\; state="\{\{state\}\}">max</figure-callout>}}{\mathrm{SINR}}_{\mathrm{the\; ki}})\right]$ (Formula 5)

相近似。若考虑到_m是复合高斯随机变量，并且对k和m是单一变量，则similar. If it is considered that _m is a compound Gaussian random variable and is a single variable for k and m, then

${\mathrm{SINR}}_{\mathrm{km}}=\frac{z}{m_b/{\mathrm{\&rho;}}_0+y^1}$(公式6)${\mathrm{SINR}}_{\mathrm{km}}=\frac{z}{m_b/{\mathrm{\&rho;}}_0+{\mathrm{the\; y}}^1}$ (Formula 6)

这里，z和y分别依照X²(2)分布及X²(2m_b-2)分布。SINR_km的累计分布函数(CDF：Cumulative distribution function)为Here, z and y follow X² (2) distribution and X² (2m_b -2) distribution, respectively. The cumulative distribution function (CDF: Cumulative distribution function) of SINR_km is

$F_S\left(x\right)=1-\frac{e^{-\frac{m_{b}x}{{\mathrm{\&rho;}}_0}}}{{(1+x)}^{m_b-1}},x\&GreaterEqual;0$(公式7)$f_S\left(x\right)=1-\frac{e^{-\frac{m_{b}x}{{\mathrm{\&rho;}}_0}}}{{(1+x)}^{m_b-1}},x\&Greater\; Equal;0$ (Formula 7)

因而，m_b发送时的系统容量为Therefore, the system capacity when m_b is sent is

$R\left(m_b\right)=m_b{\&Integral;}_0^{\&infin;}\log (1+x)d{F_S}^K\left(x\right)$(公式8)$R\left(m_b\right)=m_b{\&Integral;}_0^{\&infin;}\log (1+x)d{f_S}^K\left(x\right)$ (Formula 8)

发送波束数的最佳值为The optimal value of the number of beams to be sent is

${\hat{m}}_b=\arg \underset{1\&le;m_b\&le;m_t}{\max }R\left(m_b\right)$(公式9)${\hat{m}}_b=\mathrm{<figure-callout\; label="arg\; max"\; filenames="A20061009176300161.png,A20061009176300171.png"\; state="\{\{state\}\}">arg</figure-callout>}\underset{}{\max }\underset{1\&le;m_b\&le;m_t}{}R\left(m_b\right)$ (Formula 9)

例如，在低SNR时，设为ρ0→0，并且如果$u={F_S}^K\left(x\right),$则根据For example, at low SNR, set ρ0→0, and if$u={f_S}^K\left(x\right),$ then according to

$\frac{\&PartialD;R\left(m_b\right)}{\&PartialD;m_b}=m_b{\&Integral;}_0^1\log (1+\frac{{\mathrm{\&rho;}}_0}{m_b}\log \frac{1}{1-u^{1/K}})\mathrm{du}-{\&Integral;}_0^1\frac{\frac{{\mathrm{\&rho;}}_0}{m_b}\log \frac{1}{1-u^{1/K}}}{1+\frac{{\mathrm{\&rho;}}_0}{m_b}\log \frac{1}{1-u^{1/K}}}$(公式10)$\frac{\&PartialD;R\left(m_b\right)}{\&PartialD;m_b}=m_b{\&Integral;}_0^1\log (1+\frac{{\mathrm{\&rho;}}_0}{m_{\mathrm{<figure-callout\; label="b\; log"\; filenames="A20061009176300161.png,A20061009176300171.png"\; state="\{\{state\}\}">b</figure-callout>}}}\log \frac{1}{1-{\mathrm{<figure-callout\; label="u"\; filenames="A20061009176300161.png,A20061009176300171.png"\; state="\{\{state\}\}">u</figure-callout>}}^{1/K}})\mathrm{du}-{\&Integral;}_0^1\frac{\frac{{\mathrm{\&rho;}}_0}{m_{\mathrm{<figure-callout\; label="b\; log"\; filenames="A20061009176300161.png,A20061009176300171.png"\; state="\{\{state\}\}">b</figure-callout>}}}\log \frac{1}{1-{\mathrm{<figure-callout\; label="u"\; filenames="A20061009176300161.png,A20061009176300171.png"\; state="\{\{state\}\}">u</figure-callout>}}^{1/\mathrm{<figure-callout\; label="K"\; filenames="A20061009176300161.png,A20061009176300171.png"\; state="\{\{state\}\}">K</figure-callout>}}}}{1+\frac{{\mathrm{\&rho;}}_0}{m_{\mathrm{<figure-callout\; label="b\; log"\; filenames="A20061009176300161.png,A20061009176300171.png"\; state="\{\{state\}\}">b</figure-callout>}}}\log \frac{1}{1-{\mathrm{<figure-callout\; label="u"\; filenames="A20061009176300161.png,A20061009176300171.png"\; state="\{\{state\}\}">u</figure-callout>}}^{1/K}}}$ (Formula 10)

$<span><span>></span>></span>{<span><span>\&Integral;</span>\&Integral;</span>}_{\mathrm{<span><span>0</span>0</span>}}^{\mathrm{<span><span>1</span>1</span>}}{<span><span>(</span>(</span>\frac{{\mathrm{<span><span>\&rho;</span>\&rho;</span>}}_{\mathrm{<span><span>0</span>0</span>}}}{{\mathrm{<span><span>m</span>m</span>}}_{\mathrm{<span><span>b</span><figure-callout\; label="b\; log"\; filenames="A20061009176300161.png,A20061009176300171.png"\; state="\{\{state\}\}">b</figure-callout></span><figure-callout\; label="b\; log"\; filenames="A20061009176300161.png,A20061009176300171.png"\; state="\{\{state\}\}"></figure-callout>}}}\mathrm{<span><span></span></span>}\mathrm{<span><span>log</span>log</span>}\frac{\mathrm{<span><span>1</span>1</span>}}{\mathrm{<span><span>1</span>1</span>}<span><span>-</span>-</span>{\mathrm{<span><span>u</span><figure-callout\; label="u"\; filenames="A20061009176300161.png,A20061009176300171.png"\; state="\{\{state\}\}">u</figure-callout></span>}}^{\mathrm{<span><span>1</span>1</span>}<span><span>/</span>/</span>\mathrm{<span><span>K</span>K</span>}}}<span><span>)</span>)</span>}^{\mathrm{<span><span>2</span>2</span>}}\mathrm{<span><span>du</span>du</span>}<span><span>></span>></span>\mathrm{<span><span>0</span>0</span>}$

成为become

${\hat{m}}_b=m_t$(公式11)，${\hat{m}}_b=m_t$ (Formula 11),

在发送波束数较多时，系统容量成为最大。另一方面，在高SNR时，因为ρ0→∞，所以根据When the number of transmission beams is large, the system capacity becomes maximum. On the other hand, at high SNR, since ρ0 → ∞, according to

$R\left(m_b\right)=\frac{m_b}{m_b-1}{\&Integral;}_0^1\log \frac{1}{1-u^{1/K}}\mathrm{du},\mathrm{for}{m}_b>1$(公式12)$R\left(m_b\right)=\frac{m_b}{m_b-1}{\&Integral;}_0^1\mathrm{<figure-callout\; label="log"\; filenames="A20061009176300161.png,A20061009176300171.png"\; state="\{\{state\}\}">log</figure-callout>}\frac{1}{1-{\mathrm{<figure-callout\; label="u"\; filenames="A20061009176300161.png,A20061009176300171.png"\; state="\{\{state\}\}">u</figure-callout>}}^{1/K}}\mathrm{du},\mathrm{for}{m}_b>1$ (Formula 12)

并且and

$R\left(1\right)={\&Integral;}_0^{\&infin;}\log (1+x)\frac{1}{{\mathrm{\&rho;}}_0}{e}^{-\frac{x}{{\mathrm{\&rho;}}_0}}\mathrm{dx}>R\left(2\right)={\&Integral;}_0^1\log \frac{1}{1-u^{1/K}}\mathrm{du}$(公式13)$R\left(1\right)={\&Integral;}_0^{\&infin;}\log (1+x)\frac{1}{{\mathrm{\&rho;}}_0}{e}^{-\frac{x}{{\mathrm{\&rho;}}_0}}\mathrm{dx}>R\left(2\right)={\&Integral;}_0^1\mathrm{<figure-callout\; label="log"\; filenames="A20061009176300161.png,A20061009176300171.png"\; state="\{\{state\}\}">log</figure-callout>}\frac{1}{1-{\mathrm{<figure-callout\; label="u"\; filenames="A20061009176300161.png,A20061009176300171.png"\; state="\{\{state\}\}">u</figure-callout>}}^{1/K}}\mathrm{du}$ (Formula 13)

为for

${\hat{m}}_b=1$(公式14)${\hat{m}}_b=1$ (Formula 14)

由上面的研究得知，根据SNR，最佳的m_b有所不同。也就是说，在SNR较低的情形下，如果同时发送波束数较多，则系统容量增高。另一方面，在SNR较高的情形下，利用单波束的发送的方式在系统容量上有优势。Known from the above research, according to the SNR, the best m_b is different. That is to say, in the case of low SNR, if more beams are transmitted at the same time, the system capacity will increase. On the other hand, in the case of a high SNR, the transmission mode using a single beam has an advantage in system capacity.

发送波束及发送目标用户的组合{B，U}是由The combination {B, U} of sending beam and sending target user is given by

$\{B,U\}=\arg \underset{B\&Element;\hat{B},U\&Element;\hat{U}}{\max }\underset{k\&Element;U,m\&Element;B}{\mathrm{\&Sigma;}}\log (1+{\mathrm{SINR}}_{\mathrm{km}})$(公式15)$\{B,u\}=\arg \underset{B\&Element;\hat{B},u\&Element;\hat{u}}{\max }\underset{k\&Element;u,m\&Element;B}{\mathrm{\&Sigma;}}\log (1+{\mathrm{SINR}}_{\mathrm{km}})$ (Formula 15)

得到的。owned.

图2是表示基站装置和终端装置顺序的顺序图。首先，基站按规定的每一时间间隙发送随机的m_t条导频信号(步骤201)。终端装置根据该信息推测各波束的SINR_km，将其最大值和作为最大值的波束ID对基站装置进行报告(步骤202)。在基站装置中，根据所得到的最大SINR信息，使用(公式15)来确定应发送的波束和用户。将确定结果预先通知给终端装置(步骤203)。在步骤203中所指定的频率及定时，基站装置发送面向该用户的无线信号；在步骤203中所指定的频率及定时，终端装置接收无线信号，并接收面向该终端装置的信号(步骤204)。FIG. 2 is a sequence diagram showing the sequence of a base station device and a terminal device. First, the base station sends random m_t pilot signals at each specified time slot (step 201). The terminal device estimates the SINR_km of each beam based on this information, and reports the maximum value and the beam ID that is the maximum value to the base station device (step 202). In the base station apparatus, the beam and user to be transmitted are determined using (Formula 15) based on the obtained maximum SINR information. The determination result is notified to the terminal device in advance (step 203). At the frequency and timing specified instep 203, the base station device sends a wireless signal facing the user; at the frequency and timing specified instep 203, the terminal device receives the wireless signal, and receives the signal facing the terminal device (step 204) .

本发明的无线装置(基站及终端)进行由特定的时间间隙构成的时隙动作。按每个时隙更新上述随机波束的权重，对发送信号乘上新的波束权重。作为波束权重的制作方法示例，一般是使用Schmidt正交化的方法。根据随机数的不同，准备m_t-1个随机向量(m_t×1)。采用Schmidt正交化的算法，生成m_t独立的权重向量。图3是采用阴影的图样表示在每个时隙制作独立的m_t波束的状态。因为使用了随机数和Schmidt的正交化，所以波束权重按每个时隙产生变化，并且在时间上和空间上成为随机。为了实用化，也可以预先充分计算能看作随机之种类的天线权重，将其存储于基站装置的存储器中。如果按每个时隙通过上述存储器的查表，参照天线权重，则不再需要为每个时隙进行随机数的生成及Schmidt正交化的运算。The wireless device (base station and terminal) of the present invention performs a slot operation consisting of specific time slots. The above random beam weights are updated for each slot, and the transmission signal is multiplied by the new beam weights. As an example of a method of creating beam weights, a method of using Schmidt orthogonalization is generally used. According to different random numbers, prepare m_t -1 random vectors (m_t ×1). Using the Schmidt orthogonalization algorithm, m_t independent weight vectors are generated. Fig. 3 shows the state of making independent m_t beams in each time slot with shaded patterns. Since a random number and Schmidt's orthogonalization are used, the beam weight changes for each slot and becomes random temporally and spatially. For practical use, antenna weights that can be regarded as random may be fully calculated in advance and stored in the memory of the base station apparatus. If the antenna weights are referred to through the look-up table of the above-mentioned memory for each time slot, it is no longer necessary to perform random number generation and Schmidt orthogonalization operations for each time slot.

图4是表示基站装置结构的结构图。为了进行信道推测所发送的导频信号是由导频信号生成单元104生成的。所生成的导频通过空间调制单元105乘上阵列权重，成为被空间调制后的导频信号。网络接口101从网络所取出的应发送的用户数据，在调制单元102中按照由资源管理器109指示的调制方式(MCS)进行调制。调制后的信号在权重乘法单元103中，乘上阵列权重，调制成被空间调制后的信号。被空间调制后的信号在信号合成单元106中，和上述被空间调制后的导频在时间上多重，成为发送信号，在图4中未记述的RF部中经过从基带信号向RF信号的转换后，经由双工器107从天线进行发送。与终端发送的SINR有关的信息在天线接收之后，经由双工器107，在图4中未记述的RF部从RF信号转换成基带信号，通过解调单元108作为SINR信息加以取出。所取出的信号传送给资源管理器109。资源管理器109根据多个用户的SINR信息，按照(公式15)所示的算法来确定发送波束和发送目标用户。另外，还根据此时得到的推测SINR，确定发送的MCS。FIG. 4 is a configuration diagram showing the configuration of a base station apparatus. The pilot signal transmitted for channel estimation is generated by pilotsignal generating section 104 . The generated pilot is multiplied by the array weight by thespatial modulation unit 105 to become a spatially modulated pilot signal. The user data to be transmitted, which is fetched from the network by thenetwork interface 101 , is modulated in themodulation unit 102 according to the modulation scheme (MCS) instructed by theresource manager 109 . The modulated signal is multiplied by the array weight in theweight multiplication unit 103 to be modulated into a spatially modulated signal. The spatially modulated signal is temporally multiplexed with the aforementioned spatially modulated pilot in thesignal synthesis unit 106 to become a transmission signal, and undergoes conversion from a baseband signal to an RF signal in the RF section not shown in FIG. 4 After that, it transmits from the antenna via theduplexer 107 . The information related to the SINR transmitted by the terminal is received by the antenna, and converted from an RF signal to a baseband signal by an RF section not shown in FIG. The fetched signal is sent to theresource manager 109 . Theresource manager 109 determines the transmission beam and the transmission target user according to the algorithm shown in (Formula 15) according to the SINR information of multiple users. In addition, the MCS to be transmitted is also determined based on the estimated SINR obtained at this time.

图5是表示终端装置结构的结构图。天线所接收到的基站装置所发送的导频信号通过双工器301，输入给解调单元302，并在此推测SINR。所推测出的SINR由资源管理器303按每个波束进行比较，选择SINR最大的波束，该SINR和波束的ID传送给调制单元305。在调制单元305中，按照规定的调制方式，来调制SINR和波束ID。调制信号由附图中未记述的RF部将其从基带信号调制成RF信号，通过双工器从天线进行发送。下行线路的数据信号通过双工器301在解调部302进行解调，并通过网络接口304向网络进行发送。FIG. 5 is a configuration diagram showing the configuration of a terminal device. The pilot signal transmitted from the base station apparatus received by the antenna passes through theduplexer 301, and is input to thedemodulation section 302, where the SINR is estimated. Theresource manager 303 compares the estimated SINR for each beam, selects the beam with the highest SINR, and transmits the SINR and the ID of the beam to themodulation section 305 . Inmodulation section 305, the SINR and the beam ID are modulated according to a predetermined modulation method. The modulated signal is modulated from a baseband signal to an RF signal by an RF section not shown in the drawing, and transmitted from an antenna through a duplexer. The downlink data signal is demodulated by thedemodulation unit 302 through theduplexer 301 and transmitted to the network through thenetwork interface 304 .

根据上面的步骤、装置结构，随机波束的数目可以适当进行变化，第一课题得以解决。另外，因为同时发送的波束数通过使用(公式15)而清楚，所以第二课题也得以解决。According to the above steps and device structure, the number of random beams can be changed appropriately, and the first problem can be solved. In addition, since the number of beams to be transmitted simultaneously is clear by using (Formula 15), the second problem is also solved.

在本实施示例中，虽然未特别对调制方式进行记述，但是作为1次调制也可以使用CDMA或OFDMA，作为2次调制也可以使用QPSK或16QAM等一般调制方式。In this embodiment example, although the modulation scheme is not particularly described, CDMA or OFDMA may be used as the primary modulation, and general modulation schemes such as QPSK or 16QAM may be used as the secondary modulation.

另外，虽然在图2中记述了在信道分配之后通知信道分配结果的顺序(步骤203)，但是也可以省去本顺序，随意接受数据发送。In addition, although the procedure of notifying the result of channel assignment after channel assignment is described in FIG. 2 (step 203), this procedure may be omitted and data transmission may be freely accepted.

另外，当1个终端装置具备多个天线时，可以同时发送多个数据流。此时，终端装置需要增加对基站装置报告的SINR数。逻辑上构成的信道通过考虑为如别的终端那样，从而可以直接适用公式15的算法。这种情况下，因为可以同时传输多个数据流，所以根据MIMO中传输路径多路化的效果，可以大幅提高该终端的传输速率。终端也可以导入下述功能，即使用适当的信号合成单元对由多个天线所接收到的信号进行合成，来提高信号质量。Also, when one terminal device is equipped with multiple antennas, multiple data streams can be transmitted simultaneously. In this case, the terminal device needs to increase the number of SINRs reported to the base station device. By considering logically configured channels as other terminals, the algorithm of Equation 15 can be directly applied. In this case, since multiple data streams can be transmitted at the same time, the transmission rate of the terminal can be greatly increased according to the effect of multiplexing transmission paths in MIMO. The terminal may also introduce a function of combining signals received by multiple antennas by using an appropriate signal combining unit to improve signal quality.

产业上的可利用性Industrial availability

根据本发明，在蜂窝通信中，当实施随机波束形成时，可以决定与传播环境相应的发送波束数，能够使系统的容量最大化。According to the present invention, when performing random beamforming in cellular communication, the number of transmission beams can be determined according to the propagation environment, and the capacity of the system can be maximized.

Claims (8)

1. A wireless system, characterized by:

one or more terminals report SINR results of respective beams to a base station apparatus based on a pilot signal after random beamforming transmitted from the base station apparatus having a plurality of antennas, and the base station apparatus determines the number of beams at the time of transmitting data based on the reported SINR results.

2. The wireless system of claim 1, wherein:

the base station apparatus determines the number of beams when transmitting the data so that the system capacity becomes maximum, based on the SINR result reported from the terminal.

3. The wireless system of claim 1, wherein:

the base station apparatus sets the number of beams when transmitting the data to the number of transmission antennas when the SNR and the SINR almost match, and sets the number of beams when transmitting the data to 1 when the SNR is sufficiently larger than the SINR.

4. A base station device is characterized in that,

the disclosed device is provided with: a pilot generation unit that generates a plurality of orthogonal array weights for random beamforming and multiplies a pilot signal by the array weights to generate a pilot signal subjected to random beamforming; a transmitting unit configured to transmit the generated pilot signal to a terminal; a reception unit configured to receive SINR information from the terminal; a resource management unit for determining the number of transmitted beams, the users to transmit, and the beams to transmit, based on the SINR information transmitted from the terminal; the transmission unit transmits data to the terminal using the beam selected by the resource management unit.

5. The base station apparatus according to claim 4, characterized in that:

the resource management unit determines the number of transmitted beams so that the system capacity of the entire base station apparatus is maximized, based on SINR information received from the terminal.

6. The base station apparatus according to claim 4, characterized in that:

when the SNR and SINR almost match, the number of transmitted beams is made to match the number of transmission antennas, and when the SNR is sufficiently larger than the SINR, the number of transmitted beams is set to 1.

7. A terminal device is characterized in that,

the disclosed device is provided with: an SINR measuring unit for receiving a plurality of pilot signals after random beam forming transmitted from a base station and measuring or estimating SINR of the pilot signals; a resource management unit for selecting a beam capable of obtaining the highest SINR based on the measurement or estimation result of the SINR measurement unit; and a modulation unit configured to modulate the beam selected by the resource management unit and the SINR and report the modulated beam and the SINR to the base station.

8. The terminal device according to claim 7, characterized in that:

a plurality of receiving antennas for performing MIMO reception; the number X of the predetermined number smaller than the number of the reception antennas is determined in advance, and the ID of the beam and the measurement or estimation result of the SINR of the beam are determined for the X beams based on the measurement or estimation result of the SINR and transmitted to the base station.

Images