阅读说明：本技术 下位无线基站、上位无线基站及无线基站系统 (Lower radio base station, upper radio base station, and radio base station system ) 是由 西本浩 平明德 内田繁 于 2017-06-27 设计创作，主要内容包括：本发明的下位基站(20)具备：CSI取得部(221),其取得表示与1个以上的移动终端之间的传输路径状态的传输路径信息；下位调度器部(21),其向上位基站(10)发送传输路径信息,根据由上位无线基站通知的从所述1个以上的移动终端中选择出的移动终端即发送目的地终端、以及发送目的地终端的数据传输速度,来决定发送目的地终端的信号流数及调制编码方式；以及MU-MIMO信号处理部(222),其针对移动终端进行多用户多输入多输出(Multi User-Multiple Input Multiple Output)预编码。(A lower base station (20) of the present invention is provided with: a CSI acquisition unit (221) that acquires transmission channel information indicating the transmission channel state with 1 or more mobile terminals; a lower scheduler unit (21) that transmits channel information to the upper base station (10), and determines the number of signal streams and modulation and coding scheme of the transmission destination terminal based on the transmission destination terminal, which is a mobile terminal selected from the 1 or more mobile terminals notified by the upper radio base station, and the data transmission rate of the transmission destination terminal; and an MU-MIMO signal processing unit (222) that performs Multi-User-Multiple Input Multiple Output (Multiple Output) precoding for the mobile terminal.)

1. A lower radio base station, characterized in that,

the lower radio base station includes:

an acquisition unit that acquires transmission path information indicating a transmission path state with 1 or more mobile terminals;

a scheduler unit that transmits the propagation path information to an upper radio base station, and determines the number of signal streams and modulation and coding scheme of the transmission destination terminal based on a transmission destination terminal, which is a mobile terminal selected from the 1 or more mobile terminals notified by the upper radio base station, and a data transmission rate of the transmission destination terminal; and

and a signal processing unit configured to perform multi-user multiple-input multiple-output precoding for the mobile terminal.

2. The lower wireless base station according to claim 1,

the transmission path information is a value indicating a transmission path state with the mobile terminal by a real number scale.

3. The lower wireless base station according to claim 2,

the transmission path information is calculated from the transmission power of the mobile terminal, the number of antennas of the mobile terminal, the thermal noise power in the mobile terminal, and a transmission path matrix indicating the state of a transmission path with the mobile terminal.

4. The lower wireless base station according to claim 3,

the transmission path information is C _m，j(f) Using a transmission path matrix H between a lower base station (20-m) and a mobile terminal (90-m-j) at a radio frequency f _m，j(f) The transmission power P of the mobile terminal 90-m-j _m(f) Precoding matrix, i.e. B _m(f) And omega which is a covariance matrix obtained from the transmission path information of the interfered component of the mobile terminal (90-m-j) _j(f) Thermal noise power of mobile terminal (90-m-j), i.e. sigma ² _jI being an identity matrix having the number of receiving antenna ports of the mobile terminal (90-m-j) as a matrix order, and α being a value given a weight _mAnd β _mAnd calculated according to the following formula (1),

[ formula 1]

5. A master radio base station, characterized in that,

the upper radio base station includes a scheduler unit that determines a data transfer rate of a transmission destination terminal and a transmission destination terminal to which data of a lower radio base station is to be transmitted, based on a standby buffer amount of transmission data to be transmitted to a mobile terminal and transmission path information indicating a transmission path state with the mobile terminal, the transmission path information being notified from the lower radio base station, and notifies the lower radio base station of the transmission destination terminal and the data transfer rate.

6. A radio base station system, characterized in that,

the wireless base station system includes:

the lower radio base station according to any one of claims 1 to 4; and

the upper radio base station according to claim 5.

7. A radio base station system, characterized in that,

the wireless base station system includes:

the lower radio base station according to any one of claims 1 to 4;

the upper radio base station according to claim 5; and

and a wireless device that converts the baseband signal received from the lower radio base station into a wireless signal and transmits the wireless signal to a mobile terminal.

Technical Field

The present invention relates to a lower radio base station, an upper radio base station, and a radio base station system in a radio communication system to which a Multi-User Multiple-Input Multiple-Output (Multi-User Multiple-Input Multiple-Output) scheme is applied.

Background

In recent years, research on technologies to which fifth-generation mobile communication systems are applied and activities toward standardization of fifth-generation mobile communication systems have been actively conducted. The traffic volume of a mobile communication system is assumed to be 1000 times or more than that of 2010 in 2020. Therefore, in order to realize a fifth generation mobile communication system capable of increasing the transmission amount by securing a wide frequency width, attention has been paid to effective use of radio resources and improvement of transmission efficiency.

As an example of a method for effectively utilizing radio resources and improving transmission efficiency in a fifth-generation mobile communication system, a technique described in non-patent document 1 is given. Non-patent document 1 discloses, as a wireless communication system that realizes high-speed transmission in a limited frequency band, a Multi-User MIMO (MU-User) -MIMO) system in which a Space Division Multiple Access (SDMA) scheme is applied to a MIMO (Multiple-Input Multiple-Output) system in which a plurality of antennas are provided at both a transmitter and a receiver. The MU-MIMO system is the following: the base station includes a base station having a plurality of antennas and a plurality of terminals having a plurality of antennas, and transmits to the plurality of terminals simultaneously in the same radio frequency band.

Disclosure of Invention

Problems to be solved by the invention

However, in the fifth generation mobile communication, radio waves of a higher frequency band than those used in the conventional mobile communication, that is, before the fourth generation mobile communication are expected to be used. When the frequency becomes higher, the linearity of the radio wave becomes stronger, and the attenuation with respect to the propagation distance becomes larger. Since a radio wave of a high frequency is blocked when it hits a building such as a building and a propagation distance over which 1 base station can transmit and receive becomes short, a communication area covered by 1 base station, that is, a cell is smaller than that of the conventional one in the fifth-generation mobile communication, and the number of base stations is expected to increase than before the fourth-generation mobile communication. Therefore, it is desirable to realize a base station forming each cell, that is, a base station capable of wirelessly connecting to a mobile terminal, with a simple configuration. Therefore, it is assumed that the load of processing performed by a base station that can be wirelessly connected to a mobile terminal is suppressed, which is problematic.

The present invention has been made in view of the above circumstances, and an object thereof is to obtain a lower radio base station capable of suppressing a processing load in a base station that can be wirelessly connected to a mobile terminal.

Means for solving the problems

In order to solve the above problems and achieve the object, a lower radio base station according to the present invention includes: an acquisition unit that acquires transmission path information indicating a transmission path state with 1 or more mobile terminals; a scheduler unit that transmits transmission path information to the upper radio base station, and determines the number of signal streams and modulation and coding scheme of the transmission destination terminal based on the transmission destination terminal, which is a mobile terminal selected from 1 or more mobile terminals notified by the upper radio base station, and the data transmission rate of the transmission destination terminal; and a signal processing unit which performs MultiUser-Multiple Input Multiple Output (MultiUser-Multiple Input Multiple Output) precoding on the mobile terminal.

ADVANTAGEOUS EFFECTS OF INVENTION

The lower radio base station according to the present invention has an effect of suppressing a processing load on a base station that can be wirelessly connected to a mobile terminal.

Drawings

Fig. 1 is a diagram showing a configuration example of a radio base station system according to embodiment 1.

Fig. 2 is a diagram showing a configuration example of the upper base station according to embodiment 1.

Fig. 3 is a diagram showing a configuration example of a lower base station according to embodiment 1.

Fig. 4 is a diagram showing a configuration example of a control circuit in embodiment 1.

Fig. 5 is a diagram showing a configuration example of the radio base station system according to embodiment 2.

Fig. 6 is a diagram showing a configuration example of a lower base station according to embodiment 2.

Fig. 7 is a diagram showing a configuration example of the RRH of embodiment 2.

Detailed Description

Hereinafter, the lower radio base station, the upper radio base station, and the radio base station system will be described in detail with reference to the drawings. The present invention is not limited to the embodiment.