WO2016125877A1

WO2016125877A1 - Notification method, base station, terminal, and wireless communication system

Info

Publication number: WO2016125877A1
Application number: PCT/JP2016/053453
Authority: WO
Inventors: 和也森脇; 大関　武雄; 俊明山本; 恭宏末柄
Original assignee: Kddi株式会社
Priority date: 2015-02-06
Filing date: 2016-02-05
Publication date: 2016-08-11
Also published as: JP2016146554A

Abstract

This base station: generates a downlink signal that includes, as extraction information, first-terminal reference information used in estimating the distribution of power to a signal addressed to a first terminal in the downlink signal and other-terminal reference information used in estimating the distribution of power to signals addressed to other terminals in the downlink signal; generates a control signal that includes arrangement information indicating the position of a resource element to which each of the first-terminal reference information and other-terminal reference information in the downlink signal is allocated; and transmits the generated downlink signal and control signal to the first terminal and other terminals.

Description

Notification method, base station, terminal, and wireless communication system

The present invention relates to a notification method, a base station, a terminal, and a wireless communication system.

In order to improve frequency utilization efficiency in wireless communication networks, non-orthogonal multiple access (NOMA: Non-Orthogonal-Multiple Access), which multiplexes and transmits signals carried to multiple users on the same frequency, has been studied. (For example, refer nonpatent literature 1).

When multiplexing a signal carried to each of a plurality of users on the power axis with respect to the downlink signal, the terminal demodulates the signal addressed to the other terminal, and the downlink signal based on the demodulated signal addressed to the other terminal It is necessary to remove the signal addressed to the other terminal from the terminal and then demodulate the signal addressed to the own terminal. However, the conventional downlink signal does not include information for demodulating the signal addressed to the other terminal, and there is a problem that the signal addressed to the other terminal cannot be removed.

On the other hand, a method of transmitting information for demodulating a signal addressed to another terminal using a control channel (for example, PDCCH) is conceivable. However, in the non-orthogonal multiple access scheme, the number of users scheduled in one subframe increases. Therefore, there is a possibility that the radio resources for the control channel are exhausted by using this method.

Therefore, the present invention has been made in view of these points, and a notification method, a base station, and wireless communication capable of efficiently notifying a terminal of information for demodulating a signal addressed to another terminal from a downlink signal Provide a system. In addition, the present invention provides a terminal capable of demodulating a signal addressed to itself from a downlink signal based on the notified information.

The notification method according to the first aspect of the present invention is based on a downlink signal in which a signal destined for a first terminal destined for a first terminal and a signal destined for another terminal destined for another terminal are multiplexed on the power axis. A notification method for notifying information for extraction for extracting a signal addressed to a terminal, comprising: first terminal reference information used in a base station for estimating power distribution of the signal addressed to the first terminal in the downlink signal; A link signal generating step for generating the downlink signal including other terminal reference information used for estimation of power distribution of the signal destined for the other terminal in the downlink signal as the extraction information, and in the base station, A control signal including arrangement information indicating a position of a resource element to which each of the first terminal reference information and the other terminal reference information in a downlink signal is allocated is generated. And a control signal generating step, at the base station, and transmitting the generated said downlink signal and said control signal to said first terminal and said other terminal.

In the link signal generation step, the base station may assign the other terminal reference information to a resource element different from the resource element to which the first terminal reference information is assigned in the downlink signal.

In the link signal generation step, the base station allocates the code-multiplexed first terminal reference information and the other terminal reference information to the same resource element, and in the control signal generation step, the base station The control signal including code information used for demodulation of the code multiplexing may be generated.

In the link signal generation step, the base station may assign information indicating a value corresponding to power distribution of the signal destined for the other terminal as the other terminal reference information.

In the link signal generation step, the base station transmits, as the other terminal reference information, a signal addressed to the first terminal to a resource element different from the resource element to which the first terminal reference information is allocated in the downlink signal. A signal indicating a ratio between the power distribution and the power distribution of the signal destined for the other terminal may be allocated.

The base station according to the second aspect of the present invention separates a signal destined for the first terminal destined for the first terminal and a downlink signal in which a signal destined for the other terminal destined for the other terminal is multiplexed on the power axis. A base station that notifies extraction information for extracting a signal addressed to a terminal, the first terminal reference information used for estimating power distribution of the signal addressed to the first terminal in the downlink signal, and the downlink A downlink signal generation unit that generates the downlink signal including, as the extraction information, other terminal reference information used for estimating power distribution of the signal addressed to the other terminal in the signal, and the first terminal in the downlink signal A control signal generating unit that generates a control signal including arrangement information indicating a position of a resource element to which each of reference information and the other terminal reference information is allocated; and the generated downlink link The signal and the control signal, and a transmission unit that transmits to the first terminal and the other terminals.

The terminal according to the third aspect of the present invention extracts a signal addressed to itself from a downlink signal in which a signal addressed to itself and a signal addressed to another terminal addressed to another terminal are multiplexed on the power axis. And the other terminal used for estimating the power distribution of the signal destined for the other terminal in the downlink signal and the own terminal reference information used for the estimation of the power distribution of the signal destined for the own terminal in the downlink signal A base station comprising the downlink signal including reference information, and a control signal including arrangement information indicating a position of a resource element to which each of the own terminal reference information and the other terminal reference information in the downlink signal is allocated. Based on the arrangement information included in the control signal and the receiving unit that receives from the other terminal reference information, the power allocation of the signal addressed to the other terminal is estimated, and the downlink link A first demodulator for demodulating the signal destined for the other terminal based on the estimated power distribution of the signal destined for the other terminal, and a removing unit for removing the demodulated signal destined for the other terminal from the downlink signal. Based on the arrangement information included in the control signal, the power distribution of the signal destined to the own terminal is estimated from the reference information of the own terminal, and the estimated from the downlink signal from which the signal destined for the other terminal is removed A second demodulator that demodulates the signal destined to the own terminal based on power distribution of the signal destined to the own terminal.

The wireless communication system according to the fourth aspect of the present invention transmits and receives a downlink signal in which a signal destined for the first terminal destined for the first terminal and a signal destined for the other terminal destined for the other terminal are multiplexed on the power axis. A wireless communication system comprising a base station and a first terminal, wherein the base station is used for estimation of power distribution of a signal addressed to a first terminal destined for the first terminal in the downlink signal. A downlink signal generation unit that generates the downlink signal including terminal reference information and other terminal reference information used for estimation of power distribution of a signal addressed to another terminal destined for another terminal in the downlink signal; A control signal for generating a control signal including arrangement information indicating a position of a resource element to which each of the first terminal reference information and the other terminal reference information is assigned in a downlink signal And a transmission unit that transmits the generated downlink signal and the control signal to the first terminal and the other terminal, and the first terminal transmits the downlink signal and the control signal to the first terminal and the other terminal. Based on the reception information received from the base station and the arrangement information included in the control signal, the power distribution of the signal addressed to the other terminal is estimated from the other terminal reference information, and the estimated signal is estimated from the downlink signal. The control signal includes a first demodulator that demodulates the signal destined for the other terminal based on power distribution of the signal destined for the other terminal, a removal unit that removes the demodulated signal destined for the other terminal from the downlink signal, and Power distribution of the signal addressed to the first terminal is estimated from the first terminal reference information based on the arrangement information, and the estimated first terminal addressed from the downlink signal from which the signal addressed to the other terminal is removed Signal power Based on the distribution, and a second demodulator for demodulating the first terminal addressed signal.

According to the present invention, there is an effect that information for demodulating a signal addressed to another terminal from a downlink signal can be efficiently notified to the terminal. Further, according to the present invention, there is an effect that the terminal can demodulate the signal addressed to itself from the downlink signal based on the notified information.

Other features and advantages of the present invention will become apparent from the following description with reference to the accompanying drawings. In the accompanying drawings, the same or similar components are denoted by the same reference numerals.

The accompanying drawings are included in the specification, constitute a part thereof, show an embodiment of the present invention, and are used to explain the principle of the present invention together with the description.
It is a figure which shows the outline | summary of the radio | wireless communications system which concerns on 1st Embodiment. It is a figure which shows the structure of the flame | frame in a radio | wireless communications system. It is a block diagram of the base station which concerns on 1st Embodiment. It is a figure which shows the resource block corresponding to the downlink signal which concerns on 1st Embodiment. It is a block diagram of the 1st terminal which concerns on 1st Embodiment. It is a sequence diagram which shows the flow of the process which concerns on transmission / reception of the downlink signal which concerns on 1st Embodiment. It is a figure which shows the resource block corresponding to the downlink signal which concerns on 2nd Embodiment. It is a figure which shows the resource block corresponding to the downlink signal which concerns on 3rd Embodiment. It is a figure explaining the signal which the 2nd terminal reference information concerning a 3rd embodiment shows.

<First Embodiment>
FIG. 1 is a diagram illustrating an overview of a wireless communication system S according to the first embodiment. The radio communication system S is a system that supports, for example, LTE (Long Term Evolution), and for the downlink, an orthogonal frequency-division multiple access (OFDMA) system and a non-orthogonal multiple access system are used. (NOMA) and this system.

Here, the configuration of a frame for performing signal transmission in the wireless communication system S will be described. FIG. 2 is a diagram illustrating a frame configuration in the wireless communication system S. In the wireless communication system S, the time length of the frame is 10 ms. The frame is composed of subframes having a time length of 1 ms, and the frame includes 10 subframes. The subframe includes two slots having a time length of 0.5 ms. The slot is composed of a plurality of resource blocks divided every 180 kHz. The resource block is composed of a plurality of resource elements separated by a frequency axis and a time axis.

In the present embodiment, a signal carried by a resource block in the downlink is referred to as a downlink signal. The downlink signal is, for example, a PDCCH (Physical Downlink Control Channel) signal and a PDSCH (Physical Downlink Shared Channel) signal. The downlink signal includes a data signal in which a signal destined for each of a plurality of terminals is multiplexed on the power axis, reference information referred to for extracting a signal destined for the terminal, and the like.

The radio communication system S includes a base station 1 and a plurality of terminals as shown in FIG. As an example of a plurality of terminals, FIG. 1 shows a first terminal 2A and a second terminal 2B. In the present embodiment, the base station 1 is, for example, an LTE radio base station (eNB). The first terminal 2 </ b> A and the second terminal 2 </ b> B are mobile phones such as smartphones, and exist in an area where wireless communication with the base station 1 is possible.

The base station 1 changes the power distribution of signals destined for each terminal included in the downlink signal according to the reception environment of the plurality of terminals. The base station 1 assigns a small signal power distribution addressed to a terminal having a high S / N ratio, and assigns a large signal power distribution addressed to a terminal having a low S / N ratio. In the example shown in FIG. 1, the base station 1 makes the power distribution of the signal destined for the first terminal destined for the first terminal 2A smaller than the power allocation of the signal destined for the second terminal destined for the second terminal 2B. assign.

The base station 1 uses the first terminal reference information used for estimating the power distribution of the signal destined for the first terminal in the downlink signal and the data signal multiplexed with the signal destined for the first terminal and the signal destined for the second terminal on the power axis. And a second terminal reference information (other terminal reference information) used for estimation of power distribution of the second terminal addressed signal (another terminal addressed signal) in the downlink signal is generated. Further, the base station 1 transmits a control signal including arrangement information indicating the position (frequency band and time slot) of the resource element to which each of the first terminal reference information and the second terminal reference information is assigned in the downlink signal. Generate.

Subsequently, the base station 1 transmits the generated downlink signal and control signal to the first terminal 2A and the second terminal 2B.

Since the S / N ratio of the signal received by the first terminal 2A from the base station 1 is large, the first terminal 2A receives the downlink signal in a state where the signal addressed to the first terminal and the signal addressed to the second terminal interfere with each other by multiplexing. Receive. The first terminal 2A specifies second terminal reference information in the downlink signal based on the arrangement information included in the control signal. The first terminal 2A estimates the power distribution of the signal addressed to the second terminal based on the specified second terminal reference information, and demodulates the signal addressed to the second terminal from the downlink signal based on the estimated power distribution. The first terminal 2A removes the signal addressed to the second terminal from the downlink signal based on the demodulated signal addressed to the second terminal.

Subsequently, the first terminal 2A specifies the first terminal reference information in the downlink signal based on the arrangement information included in the control signal. The first terminal 2A estimates the power distribution of the signal addressed to the first terminal based on the identified first terminal reference information, and based on the estimated power distribution, the first terminal 2A Demodulate a signal addressed to one terminal.

On the other hand, since the signal-to-noise ratio of the signal received by the second terminal 2B is small, in the downlink signal received by the second terminal 2B, the signal addressed to the first terminal having a small power distribution is sufficiently weak and included as noise. Therefore, the second terminal 2B can directly demodulate the signal addressed to the second terminal from the downlink signal.

As described above, the radio communication system S generates a downlink signal including the second terminal reference information for demodulating the signal addressed to the second terminal, and resources to which the second terminal reference information in the downlink signal is allocated. A control signal including arrangement information indicating the position of the element is generated, and the downlink signal and the control signal are transmitted to the first terminal 2A. By doing so, only the arrangement information having a smaller size than the second terminal reference information is newly added to the downlink control signal. Information for demodulating the signal addressed to the terminal can be notified to the terminal efficiently.

Subsequently, the configurations of the base station 1 and the first terminal 2A will be described.

[Configuration Example of Base Station 1]
First, the functional configuration of the base station 1 will be described. FIG. 3 is a configuration diagram of the base station 1 according to the first embodiment.

The base station 1 includes a downlink signal generation unit 11, a control signal generation unit 12, a transmission unit 13, and an antenna 14.

The downlink signal generation unit 11, the control signal generation unit 12, and the transmission unit 13 are configured by an RF (Radio Frequency) circuit that modulates and demodulates a signal.

When the downlink signal generation unit 11 receives information destined for the first terminal 2A and information destined for the second terminal 2B from an upper station (not shown) of the base station 1, the downlink signal generation unit 11 sets the first terminal 2A as the destination. A downlink signal is generated by multiplexing the signal addressed to the first terminal and the signal addressed to the second terminal destined for the second terminal 2B on the power axis.

Specifically, the downlink signal generation unit 11 extracts the data signal addressed to the individual terminal from the data signal in which the signal addressed to the first terminal and the signal addressed to the second terminal are multiplexed on the power axis. A downlink signal including the extraction information is generated. Here, the information for extraction is used for the first terminal reference information used for estimating the power distribution of the signal destined for the first terminal in the downlink signal, and for the estimation of the power distribution of the signal destined for the second terminal in the downlink signal. Second terminal reference information.

In the first embodiment, the downlink signal generation unit 11 assigns the second terminal reference information to a resource element different from the resource element to which the first terminal reference information is assigned in the downlink signal. Here, the first terminal reference information is information indicating an analog value corresponding to the absolute value of the power allocated to the signal addressed to the first terminal. The second terminal reference information is information indicating an analog value corresponding to the power distribution of the signal addressed to the second terminal. The second terminal reference information is information indicating an analog value corresponding to the absolute value of the power allocated to the signal addressed to the second terminal, for example. In this way, by using the second terminal reference information as information indicating an analog value, it is possible to flexibly determine power allocation or flexibly perform terminal pairing according to the SN ratio of each of a plurality of terminals. You can do it. Further, the first terminal 2A on the receiving side can perform highly accurate replica reproduction.

FIG. 4 is a diagram illustrating resource blocks corresponding to the downlink signal according to the first embodiment.

FIG. 4 shows a plurality of resource elements obtained by dividing resource blocks corresponding to downlink signals in the frequency direction and the time direction. In FIG. 4, the first terminal reference information is assigned to the resource element RE1 painted black. In the example illustrated in FIG. 4, one first terminal reference information is allocated to two consecutive resource elements, and a total of six first terminal reference information is allocated.

Further, the second terminal reference information is assigned to the resource element RE2 in which a plurality of horizontal lines are drawn. In the example illustrated in FIG. 4, one second terminal reference information is assigned to two consecutive resource elements, and two second terminal reference information are assigned in total. In the example illustrated in FIG. 4, two pieces of second terminal reference information are assigned in total. However, the present invention is not limited to this, and three or more pieces of second terminal reference information may be assigned.

Further, other reference information (for example, cell-specific reference information (CRS), channel quality reference information (CSI-RS), position reference information (PRS)) is assigned to the resource element RE3 in which a plurality of diagonal lines are drawn. ing. The white resource element RE4 is assigned a data signal in which a signal addressed to the first terminal and a signal addressed to the second terminal are multiplexed on the power axis.

When the control signal generation unit 12 receives information destined for the first terminal 2A and information destined for the second terminal 2B from the upper station of the base station 1, the control signal generation unit 12 generates a control signal for controlling the downlink. Specifically, the control signal generation unit 12 includes control information including arrangement information indicating the position of the resource element to which each of the first terminal reference information and the second terminal reference information is assigned in the resource block corresponding to the downlink signal. Generate a signal.

The transmission unit 13 transmits the generated downlink signal and control signal to the first terminal 2A and the second terminal 2B. Specifically, the transmission unit 13 radiates the generated downlink signal and control signal from the antenna 14 so that the downlink signal and control signal are present in an area where communication with the base station 1 is possible. Transmit to the first terminal 2A and the second terminal 2B.

[Configuration example of first terminal 2A]
Next, the functional configuration of the first terminal 2A will be described. FIG. 5 is a configuration diagram of the first terminal 2A according to the first embodiment. The first terminal 2A includes an antenna 20, a receiving unit 21, a first demodulating unit 22, a removing unit 23, a second demodulating unit 24, and a control unit 25.

The receiving unit 21, the first demodulating unit 22, the removing unit 23, and the second demodulating unit 24 are configured by an RF circuit that modulates and demodulates a signal.

The receiving unit 21 receives a downlink signal and a control signal from the base station 1 via the antenna 20.

The 1st demodulation part 22 specifies the resource element to which 2nd terminal reference information is allocated based on the arrangement | positioning information contained in a control signal. Then, the first demodulator 22 estimates the power distribution of the signal addressed to the second terminal from the second terminal reference information assigned to the resource element. Then, the first demodulator 22 demodulates the signal destined for the second terminal from the downlink signal based on the estimated power distribution of the signal destined for the second terminal. Specifically, the first demodulation unit 22 refers to the second terminal with respect to the value of the data signal included in the downlink signal and multiplexed on the power axis with the signal addressed to the first terminal and the signal addressed to the second terminal. By performing channel compensation using the channel estimation value estimated from the information, the signal addressed to the second terminal is demodulated. In this way, the signal addressed to the second terminal can be demodulated with high accuracy.

The removal unit 23 removes the demodulated second terminal addressed signal from the downlink signal. Specifically, based on the demodulated signal destined for the second terminal, the removal unit 23 is a data signal in which the signal destined for the first terminal and the signal destined for the second terminal included in the downlink signal are multiplexed on the power axis. Then, the signal component corresponding to the signal addressed to the second terminal is removed.

The second demodulator 24 identifies the resource element to which the first terminal reference information is assigned based on the arrangement information included in the control signal. Then, the second demodulator 24 estimates the power distribution of the signal addressed to the first terminal from the first terminal reference information assigned to the resource element. Then, the second demodulator 24 demodulates the signal destined for the first terminal based on the estimated power distribution of the signal destined for the first terminal from the downlink signal from which the signal destined for the second terminal has been removed. Specifically, the second demodulator 24 performs channel compensation on the value of the data signal from which the signal destined for the second terminal is removed in the downlink signal, using the channel estimation value estimated from the first terminal reference information. By doing so, the signal addressed to the first terminal is demodulated. The second demodulator 24 outputs the demodulated signal for the first terminal to the controller 25.

The control unit 25 is constituted by a CPU, for example. The control unit 25 controls functions related to the first terminal 2A by executing various programs stored in a storage unit (not shown). When the signal destined for the first terminal is input from the second demodulator 24, the control unit 25 performs processing according to the signal destined for the first terminal.

[Sequence for transmission / reception of downlink signal]
Next, the flow of processing related to transmission / reception of downlink signals in the wireless communication system S will be described. FIG. 6 is a sequence diagram showing a flow of processing relating to transmission / reception of a downlink signal according to the first embodiment.

First, the downlink signal generation unit 11 includes a data signal in which a signal addressed to the first terminal and a signal addressed to the second terminal are multiplexed on the power axis, first terminal reference information, and second terminal reference information. A link signal is generated (S10).

Subsequently, the control signal generation unit 12 generates a control signal including arrangement information indicating the position of the resource element to which each of the first terminal reference information and the second terminal reference information is assigned in the resource block corresponding to the downlink signal. Generate (S20).

Note that the processing by the downlink signal generation unit 11 and the processing by the control signal generation unit 12 may be performed in parallel.

Subsequently, the transmitting unit 13 radiates the generated downlink signal and control signal from the antenna 14, so that the downlink signal and control signal are present in an area where communication with the base station 1 is present. It transmits to the terminal 2A and the second terminal 2B.

Subsequently, when the receiving unit 21 receives the downlink signal and the control signal from the base station 1 via the antenna 20, the first demodulating unit 22 receives the second terminal address signal estimated based on the second terminal reference information. Based on the power distribution, a signal destined for the second terminal is demodulated from the downlink signal (S30).

Subsequently, the removing unit 23 removes the signal addressed to the second terminal from the downlink signal based on the demodulated signal addressed to the second terminal (S40).

Subsequently, the second demodulator 24, based on the power distribution of the signal addressed to the first terminal estimated based on the first terminal reference information, the signal addressed to the first terminal from the downlink signal from which the signal addressed to the second terminal has been removed. Is demodulated (S50).

The second terminal 2B receives the downlink signal and the control signal from the base station 1 similarly to the first terminal 2A. Here, since the signal-to-noise ratio of the signal received by the second terminal 2B is small, in the downlink signal received by the second terminal 2B, the signal addressed to the first terminal having a small power distribution is sufficiently weak and included as noise. . The second terminal 2B demodulates the signal addressed to the second terminal from the downlink signal based on the second terminal reference information (S60).

[Effect in the first embodiment]
As described above, the radio communication system S according to the first embodiment generates a downlink signal including the second terminal reference information for demodulating the signal addressed to the second terminal, and refers to the second terminal in the downlink signal. A control signal including arrangement information indicating the position of the resource element to which the information is assigned is generated, and the downlink signal and the control signal are transmitted to the first terminal 2A.

Thereby, the first terminal 2A can estimate the power distribution of the signal addressed to the second terminal from the downlink signal based on the arrangement information, and can demodulate the signal addressed to the second terminal based on the power distribution. Then, the first terminal 2A removes the signal addressed to the second terminal from the downlink signal based on the demodulated signal addressed to the second terminal, and addresses the first terminal from the downlink signal from which the signal addressed to the second terminal has been removed. The signal can be demodulated.

In addition, in the wireless communication system S, only the arrangement information having a smaller size than the second terminal reference information is added to the control signal of the downlink signal, so information for demodulating the signal addressed to the second terminal from the downlink signal is added. The terminal can be notified efficiently. Thereby, the radio | wireless communications system S can suppress that the resource allocated to the control signal is exhausted.

<Second Embodiment>
[First terminal reference information and second terminal reference information are code-multiplexed and assigned]
Next, the second embodiment will be described. The wireless communication system S of the second embodiment differs from the first embodiment in that the first terminal reference information and the second terminal reference information are code-multiplexed and assigned to the same resource element. Below, the radio | wireless communications system S which concerns on 2nd Embodiment is demonstrated with reference to drawings. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

In the second embodiment, the downlink signal generation unit 11 of the base station 1 code-multiplexes the first terminal reference information and the second terminal reference information. Then, the downlink signal generation unit 11 assigns the code-multiplexed first terminal reference information and second terminal reference information to the same resource element.

FIG. 7 is a diagram illustrating resource blocks corresponding to downlink signals according to the second embodiment. As shown in FIG. 7, it can be confirmed that the encoded first terminal reference information and second terminal reference information are allocated to the resource element RE5.

In the example shown in FIG. 7, code-multiplexed information is allocated to two consecutive resource elements RE5, and a total of two code-multiplexed information is allocated. In the example shown in FIG. 7, two pieces of code-multiplexed information in total are allocated. However, the present invention is not limited to this, and the first terminal reference information and the second information encoded for other resource elements are allocated. Terminal reference information may be assigned.

The control signal generation unit 12 generates a control signal including arrangement information indicating positions of the code-multiplexed first terminal reference information and second terminal reference information and code information used for demodulation of the code multiplexing. .

In the second embodiment, the first demodulator 22 of the first terminal 2A is assigned code-multiplexed first terminal reference information and second terminal reference information based on arrangement information included in the control signal. Locate the resource element. Then, the first demodulator 22 of the first terminal 2A extracts the first terminal reference information and the second terminal reference information that are code-multiplexed from the resource element, and performs the first based on the code information included in the control signal. The terminal reference information and the second terminal reference information are demodulated. Then, the first demodulator 22 demodulates the signal addressed to the second terminal based on the demodulated second terminal reference information.

The removal unit 23 removes the signal addressed to the second terminal from the downlink signal based on the demodulated signal addressed to the second terminal.

The second demodulator 24 demodulates the signal destined for the first terminal from the downlink signal from which the signal destined for the second terminal has been removed based on the first terminal reference information demodulated by the first demodulator 22.

[Effects of Second Embodiment]
As described above, in the radio communication system S according to the second embodiment, the base station 1 code-multiplexes the second terminal reference information for the resource element to which the first terminal reference information is assigned. There is no need to newly secure a resource element to which terminal reference information is allocated. Therefore, the radio communication system S can more efficiently notify the first terminal 2A of information for demodulating the signal addressed to the second terminal from the downlink signal.

<Third Embodiment>
[Assignment of power distribution ratios of a plurality of terminals as second terminal reference information]
Subsequently, a third embodiment will be described. The wireless communication system S of the third embodiment is different from that of the first embodiment in that a signal indicating a power distribution ratio of a plurality of terminals is assigned to the resource element as the second terminal reference information. The radio communication system S according to the third embodiment will be described below.

In 3rd Embodiment, the downlink signal production | generation part 11 of the base station 1 uses 1st as 2nd terminal reference information to the resource element different from the resource element to which 1st terminal reference information was allocated in the downlink signal. A signal indicating the ratio between the power distribution of the signal addressed to the terminal and the power distribution of the signal addressed to the second terminal is allocated.

FIG. 8 is a diagram illustrating resource blocks corresponding to downlink signals according to the third embodiment. As shown in FIG. 8, a signal indicating the ratio between the power distribution of the signal addressed to the first terminal and the power distribution of the signal addressed to the second terminal is assigned to the resource element RE6 as the second terminal reference information.

FIG. 9 is a diagram illustrating a signal indicated by the second terminal reference information according to the third embodiment. FIG. 9 shows the signal point SP, and the coordinate values (I1, Q1) of the signal point SP indicate the ratio between the power distribution of the signal addressed to the first terminal and the power distribution of the signal addressed to the second terminal. ing. For example, if the ratio between I1 and Q1 is 2: 8, it indicates that the power distribution of the signal addressed to the first terminal is 20%, and the power distribution of the signal addressed to the second terminal is 80%. ing.

In the third embodiment, the first demodulator 22 of the first terminal 2A, based on the arrangement information included in the control signal, the position of the resource element to which the first terminal reference information is allocated, and the second terminal reference information Specifies the location of the resource element to which is assigned. Then, the first demodulator 22 identifies the ratio between the power distribution of the signal destined for the first terminal and the power distribution of the signal destined for the second terminal based on the second terminal reference information. Then, the first demodulator 22 calculates the absolute value of the power allocated to the signal destined for the second terminal based on the specified ratio and the power distribution of the signal destined for the first terminal estimated from the first terminal reference information. presume. Then, the first demodulator 22 demodulates the signal addressed to the second terminal based on the estimated absolute value of the power.

The second demodulator 24 demodulates the signal addressed to the first terminal from the downlink signal from which the signal addressed to the second terminal has been removed based on the first terminal reference information.

[Effect in the third embodiment]
As described above, the radio communication system S according to the third embodiment uses the power distribution of the signal addressed to the first terminal and the power of the signal addressed to the second terminal as the second terminal reference information for demodulating the signal addressed to the second terminal. Generating a downlink signal including a signal indicating a ratio to the allocation, generating a control signal including arrangement information indicating a position of a resource element to which the second terminal reference information is allocated in the downlink signal, and generating the downlink signal The control signal is transmitted to the first terminal 2A. In this way, the first terminal 2A estimates the absolute value of the power allocated to the signal addressed to the second terminal based on the first terminal reference information and the second terminal reference information, and the signal addressed to the second terminal Can be demodulated.

As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above embodiment. In particular, the specific embodiments of the distribution / integration of the devices are not limited to those illustrated above, and all or a part thereof may be added in arbitrary units according to various additions or according to functional loads. It can be configured functionally or physically distributed and integrated.

The present invention is not limited to the above embodiment, and various changes and modifications can be made without departing from the spirit and scope of the present invention. Therefore, in order to make the scope of the present invention public, the following claims are attached.

This application claims priority on the basis of Japanese Patent Application No. 2015-022502 filed on Feb. 6, 2015, the entire contents of which are incorporated herein by reference.

Claims

Extraction information for extracting a signal addressed to an individual terminal from a downlink signal in which a signal addressed to the first terminal addressed to the first terminal and a signal addressed to the other terminal addressed to the other terminal are multiplexed on the power axis. A notification method for notification,
In the base station, the first terminal reference information used for estimating the power distribution of the signal addressed to the first terminal in the downlink signal, and the other terminal used for estimating the power distribution of the signal addressed to the other terminal in the downlink signal A link signal generating step for generating the downlink signal including reference information as the extraction information;
In the base station, a control signal generation step of generating a control signal including arrangement information indicating a position of a resource element to which each of the first terminal reference information and the other terminal reference information in the downlink signal is allocated;
In the base station, transmitting the generated downlink signal and the control signal to the first terminal and the other terminal;
A notification method comprising:
In the link signal generation step, the base station assigns the other terminal reference information to a resource element different from the resource element to which the first terminal reference information is assigned in the downlink signal.
The notification method according to claim 1.
In the link signal generation step, the base station assigns the code-multiplexed first terminal reference information and the other terminal reference information to the same resource element,
In the control signal generation step, the base station generates the control signal including code information used for demodulation of the code multiplexing.
The notification method according to claim 1.
In the link signal generation step, the base station assigns information indicating a value corresponding to power distribution of the signal destined for the other terminal as the other terminal reference information.
The notification method according to claim 2 or 3.
In the link signal generation step, the base station transmits, as the other terminal reference information, the signal addressed to the first terminal to a resource element different from the resource element to which the first terminal reference information is assigned in the downlink signal. A signal indicating a ratio between power distribution and power distribution of the signal addressed to the other terminal is allocated.
The notification method according to claim 1.
Extraction information for extracting a signal addressed to an individual terminal from a downlink signal in which a signal addressed to the first terminal addressed to the first terminal and a signal addressed to the other terminal addressed to the other terminal are multiplexed on the power axis. A base station to notify,
First terminal reference information used for estimating power distribution of the signal addressed to the first terminal in the downlink signal, and other terminal reference information used for estimating power distribution of the signal addressed to the other terminal in the downlink signal. A downlink signal generation unit that generates the downlink signal included as the extraction information;
A control signal generating unit that generates a control signal including arrangement information indicating a position of a resource element to which each of the first terminal reference information and the other terminal reference information in the downlink signal is allocated;
A transmitter that transmits the generated downlink signal and the control signal to the first terminal and the other terminal;
A base station comprising:
It is a terminal that extracts a signal addressed to its own terminal from a downlink signal in which a signal addressed to its own terminal addressed to itself and a signal addressed to another terminal addressed to another terminal are multiplexed on the power axis,
The own terminal reference information used for estimating the power distribution of the signal destined for the own terminal in the downlink signal and the other terminal reference information used for estimating the power distribution of the signal destined for the other terminal in the downlink signal A receiving unit that receives, from a base station, a downlink signal and a control signal including arrangement information indicating a position of a resource element to which each of the own terminal reference information and the other terminal reference information in the downlink signal is allocated; ,
Based on the arrangement information included in the control signal, the power distribution of the signal destined for the other terminal is estimated from the reference information of the other terminal, and based on the estimated power distribution of the signal destined for the other terminal from the downlink signal. A first demodulator that demodulates the signal addressed to the other terminal;
A removing unit for removing the demodulated signal destined for the other terminal from the downlink signal;
Based on the arrangement information included in the control signal, the power distribution of the signal destined for the own terminal is estimated from the reference information of the own terminal, and the estimated own signal is estimated from the downlink signal from which the signal destined for the other terminal is removed. A second demodulator that demodulates the signal addressed to the terminal based on power distribution of the signal addressed to the terminal;
A terminal equipped with.
A base station for transmitting and receiving a downlink signal in which a signal destined for a first terminal destined for a first terminal and a signal destined for another terminal destined for another terminal are multiplexed on a power axis, and a radio communication system including the first terminal There,
The base station
First terminal reference information used for estimating power distribution of a signal destined for the first terminal destined for the first terminal in the downlink signal, and power of a signal destined for another terminal destined for the other terminal in the downlink signal A downlink signal generation unit that generates the downlink signal including other terminal reference information used for estimation of distribution;
A control signal generating unit that generates a control signal including arrangement information indicating a position of a resource element to which each of the first terminal reference information and the other terminal reference information in the downlink signal is allocated;
A transmission unit for transmitting the generated downlink signal and the control signal to the first terminal and the other terminal;
The first terminal is
A receiving unit for receiving the downlink signal and the control signal from the base station;
Based on the arrangement information included in the control signal, the power distribution of the signal destined for the other terminal is estimated from the reference information of the other terminal, and based on the estimated power distribution of the signal destined for the other terminal from the downlink signal. A first demodulator that demodulates the signal addressed to the other terminal;
A removing unit for removing the demodulated signal destined for the other terminal from the downlink signal;
Based on the arrangement information included in the control signal, the power distribution of the signal addressed to the first terminal is estimated from the first terminal reference information, and estimated from the downlink signal from which the signal addressed to the other terminal is removed A second demodulator that demodulates the signal addressed to the first terminal based on power distribution of the signal addressed to the first terminal;
Wireless communication system.