WO2012086135A1 - Transmission device and transmission control method - Google Patents

Abstract

A transmission device of the present invention, when performing transmission control of a macro terminal, can suppress increase in the amount of transmission control information from a pico base station to a macro base station or a macro terminal while performing suitable transmission control for each macro terminal. In the device, a control information receiving unit (301) receives control information related to interference at an interfered station, whereupon a transmission control unit (302) updates, on the basis of the control information, priority degrees which are possessed by each of a plurality of different correspondence relationships, which are correspondence relationships such that control guidelines for transmission have been associated with each of a plurality of history patterns of the control information, so as to control transmission on the basis of the control guidelines which have been identified by the history of the control information which has been received and the correspondence relationships of high priority.

Description

Transmission apparatus and transmission control method

The present invention relates to a transmission device and a transmission control method.

Recently, in 3GPP-LTE (3rd Generation Partnership Project Project Radio Access Network Network Long Term Evolution) (for example, see Non-Patent Documents 1, 2, 3, and 4), heterogeneous networks have attracted attention.

A heterogeneous network is a “macro cell (Macro cell)” that covers a large area (for example, a coverage area with a cell radius of several kilometers) in order to cope with an increase in capacity in a cellular network. "Pico 呼 ば cell" (sometimes called a small cell base station) that covers a small area (for example, a cover area with a cell radius of several tens of meters) It is a network used together.

For example, in a heterogeneous network, as shown in FIG. 1, one or more pico base stations (“Pico” shown in FIG. 1) are arranged in the service area of a macro base station (“Macro” shown in FIG. 1). Is done. Here, since the macro base station covers a larger service area than the pico base station, it is effective in improving the area coverage rate. On the other hand, since the pico base station covers a smaller service area than the macro base station, the distance (frequency reuse distance) in which the same frequency can be reused is shortened, and more cells are arranged per certain area. This is effective in improving frequency utilization efficiency. That is, the purpose of the heterogeneous network is to achieve both high area coverage and high frequency utilization efficiency by arranging macro base stations and pico base stations in a complementary manner.

In addition, among base stations that cover small cells, a base station that connects only a group of terminals (Closed subscriber の group) to which access rights have been given in advance is distinguished from a pico base station as a “femto base station (femtocell : Femto cell) ". In the following description, in order to simplify the description, the pico base station and the femto base station are not distinguished from each other and are simply referred to as “pico base station”.

By the way, in a heterogeneous network, a macro base station and a pico base station may configure a service area using the same frequency. In this case, in the uplink channel, interference between the macro cell and the pico cell becomes a problem. For example, as shown in FIG. 1, in addition to a desired signal (not shown) from a terminal (macro terminal (Macro UE)) connected to the macro base station, the macro base station is within the service area of the macro base station. 1 receives interference (solid arrow shown in FIG. 1) from a terminal (pico terminal (Pico UE)) connected to a pico base station existing in the network. Similarly, the pico base station receives interference (broken arrows shown in FIG. 1) from the macro terminal. For this reason, in a heterogeneous network, it is considered to perform transmission control of pico terminals and macro terminals in the uplink channel.

The transmission control includes, for example, increase / decrease in transmission power, increase / decrease in transmission frequency, increase / decrease in frequency band used for transmission, etc., but in the following description, it is simply referred to as “transmission control”.

For example, as one transmission control method for a macro terminal, the pico base station individually controls transmission to the macro base station or the macro terminal based on individual interference information regarding interference received from each macro terminal in the uplink channel. A method of instructing is conceivable. However, in this transmission control method, the pico base station must individually notify the macro base station or the macro terminal of the interference information for each macro terminal, and there is a problem that the overhead of transmission control increases.

On the other hand, as another transmission control method of the macro terminal, the pico base station performs transmission control for all the macro base stations or all the macro terminals based on interference information related to the total interference received from each macro terminal in the uplink channel. A method of instructing uniformly can be considered. However, although this transmission control method can suppress an increase in transmission control overhead, transmission control for each macro terminal cannot be performed, and as a result, there is a problem that transmission control for each macro terminal is not optimized. is there.

Therefore, when performing transmission control of a macro terminal, a method capable of performing appropriate transmission control for each macro terminal while suppressing an increase in the amount of transmission control information from the pico base station to the macro base station or the macro terminal is desired. . The above-described problems are transmission control for suppressing interference (uplink interference) in the uplink channel from the pico terminal to the macro base station, and the downlink channel from the macro base station (pico base station) to the pico terminal (macro terminal). This is a common problem in transmission control for suppressing interference (downlink interference).

An object of the present invention is to perform appropriate transmission control for each macro terminal while suppressing an increase in the amount of transmission control information from the pico base station to the macro base station or the macro terminal, for example, when performing macro terminal transmission control. An object of the present invention is to provide a transmission device and a transmission control method that can be used.

The transmission device according to one aspect of the present invention has a correspondence relationship in which a transmission control guideline is associated with each of a reception unit that receives control information regarding interference in an interfered station and a plurality of history patterns of the control information. The priority of each of the plurality of different correspondences is updated based on the control information, and the control guideline is identified from the received history of the control information and the correspondences having a high priority. And a control unit that controls transmission.

The transmission control method of one aspect of the present invention is a correspondence relationship in which control information related to interference in an interfered station is received, and a transmission control guideline is associated with each of the plurality of history patterns of the control information, The priority of each of the plurality of different correspondence relationships is updated based on the control information, and based on the control guideline specified from the received history of the control information and the correspondence relationship having a high priority. To control transmission.

According to the present invention, for example, when performing transmission control of a macro terminal, it is possible to perform appropriate transmission control for each macro terminal while suppressing an increase in the amount of transmission control information from the pico base station to the macro base station or the macro terminal. it can.

Diagram showing an example of a heterogeneous network Main block diagram of terminal (transmitting apparatus) according to one embodiment of the present invention The block diagram which shows the structure of the base station (pico base station) which concerns on one embodiment of this invention The block diagram which shows the structure of the other base station (macro base station) which concerns on one embodiment of this invention The block diagram which shows the structure of the terminal (macro terminal) which concerns on one embodiment of this invention The figure which shows an example of the strategy group which the macro terminal which concerns on one embodiment of this invention has The figure which shows the computer simulation result which concerns on one embodiment of this invention The figure which shows the computer simulation result which concerns on one embodiment of this invention The figure which shows an example of the strategy group which the macro terminal which concerns on other embodiment of this invention has.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the embodiment, the same components are denoted by the same reference numerals, and the description thereof will be omitted because it is duplicated.

[System Overview]
The communication system according to the present embodiment includes a base station 100, another base station 200, and a terminal (sometimes referred to as a “mobile station”) 300. For example, the base station 100 is a pico base station, the other base station 200 is a macro base station, and the terminal 300 is a macro terminal connected to the other base station 200 (macro base station). In the communication system according to the present embodiment, for example, as in FIG. 1, a plurality of base stations 100 (pico base stations) are installed in a service area covered by another base station 200 (macro base station). In addition, a plurality of terminals 300 (macro terminals) are connected to another base station 200 (macro base station).

In the communication system according to the present embodiment, at least a part of the frequency band is shared between base station 100 and other base station 200. Therefore, there is a possibility that interference between the base station 100 and another base station 200 occurs in the downlink channel and the uplink channel.

That is, a terminal (pico terminal, not shown) connected to the base station 100 (pico base station) may receive interference from another base station 200 (macro base station) in the downlink channel. In addition, terminal 300 (macro terminal) may receive interference from base station 100 (pico base station) in the downlink channel. However, the terminal 300 (macro terminal) does not grasp all the information related to the base station 100 (pico base station), and merely recognizes that “it is receiving interference from somewhere”.

Similarly, the base station 100 (pico base station) may receive interference from the terminal 300 (macro terminal) connected to another base station 200 (macro base station) in the uplink channel. Further, another base station 200 (macro base station) may receive interference from a terminal (pico terminal, not shown) connected to the base station 100 (pico base station) in the uplink channel. However, since the other base station 200 (macro base station) and the base station 100 (pico base station) are connected by a backhaul line (for example, a wired line such as an optical fiber or a wireless line), the base station 100 (pico base station) and another base station 200 (macro base station) hold information related to “base stations sharing at least some frequency bands” existing in the vicinity.

Hereinafter, transmission control in terminal 300 (macro terminal) for suppressing interference received by base station 100 (pico base station) from a plurality of terminals 300 (macro terminals) will be described. That is, base station 100 is an interfered station, and terminal 300 is a transmission apparatus that performs transmission control according to the present embodiment.

In the communication system described above, base station 100 (pico base station) generates transmission control information indicating interference information related to the amount of interference that the mobile station receives from the outside, and transmits the transmission control information to another base station 200 (macro base station). Alternatively, a plurality of terminals 300 (macro terminals) are notified.

Each terminal 300 (macro terminal) is based on transmission control information notified directly from the base station 100 (pico base station) or transmission control information notified via another base station 200 (macro base station). , Perform transmission control of own machine.

FIG. 2 is a main configuration diagram of terminal 300 according to the present embodiment. In terminal 300, control information receiving section 301 receives transmission control information related to interference in base station 100 (interfered station). Then, the transmission control unit 302 has a correspondence relationship in which a transmission control guideline is associated with each of the plurality of history patterns of the transmission control information, and the transmission control unit 302 determines the priority of each of the plurality of different correspondence relationships. The transmission is updated based on the information, and the transmission is controlled based on the control guideline specified from the history of the transmission control information and the high priority correspondence.

[Configuration of Base Station 100]
FIG. 3 is a block diagram showing a configuration of base station 100 according to the present embodiment. Here, the base station 100 is, for example, a pico base station.

The RF unit 102 performs reception radio processing (down-conversion, analog-digital (A / D) conversion, etc.) on the signal received via the antenna 101, and the received signal after reception radio processing is sent to the reception baseband unit 103. Output. The received signal received via the antenna 101 includes transmission data (uplink data, that is, desired signal) for the own device transmitted from a terminal (for example, a pico terminal) connected to the own device. And signals from a plurality of terminals 300 located in the vicinity of the own device (that is, interference signals) are included. Further, the RF unit 102 performs transmission radio processing (up-conversion, digital analog (D / A) conversion, etc.) on the signal input from the transmission baseband unit 107, and transmits the signal after transmission radio processing from the antenna 101. Send.

The reception baseband unit 103 performs reception baseband processing on the reception signal input from the RF unit 102, and outputs the signal after reception baseband processing to the interference measurement unit 104.

Interference measurement section 104 detects an interference signal (a signal from terminal 300, that is, a signal other than a signal (desired signal) from a pico terminal) from the signal input from reception baseband section 103, and the detected interference signal The power (interference power) is measured as the amount of interference that the aircraft receives. Then, the interference measurement unit 104 outputs the measured interference amount to the transmission control information generation unit 105.

Based on the amount of interference input from interference measuring section 104, transmission control information generating section 105 generates interference information related to the amount of interference received by itself as transmission control information for terminal 300 (or other base station 200). To do. In base station 100, the resource group to be used is grouped in advance into several groups (resource groups), and transmission control information is generated for each group. The transmission control information is represented by 1 bit for each group, for example. Then, transmission control information generation section 105 outputs the generated transmission control information to modulation section 106. Details of the transmission control information generation processing in the transmission control information generation unit 105 will be described later.

Modulation section 106 modulates transmission data (downlink data) for a pico terminal (not shown) to which the own apparatus is connected and transmission control information input from transmission control information generation section 105, and after modulation Is output to the transmission baseband unit 107.

The transmission baseband unit 107 performs transmission baseband processing on the signal input from the modulation unit 106 and outputs the transmission signal after the transmission baseband processing to the RF unit 102.

[Configuration of Other Base Station 200]
FIG. 4 is a block diagram showing a configuration of another base station 200 according to the present embodiment. The other base station 200 is, for example, a macro base station.

Modulation section 201 modulates transmission data (downlink data) for terminal 300 (macro terminal) connected to itself and outputs the modulated transmission data to transmission baseband section 202.

The transmission baseband unit 202 performs transmission baseband processing on the transmission data input from the modulation unit 201, and outputs the transmission data after the transmission baseband processing to the RF unit 203.

The RF unit 203 performs transmission radio processing (up-conversion, digital analog (D / A) conversion, etc.) on the transmission data input from the transmission baseband unit 202, and transmits the transmission data after the transmission radio processing from the antenna 204. Send.

[Configuration of terminal 300]
FIG. 5 is a block diagram showing a configuration of terminal 300 according to the present embodiment. The terminal 300 is a macro terminal, for example.

The control information receiving unit 301 receives transmission control information for each resource group that is notified (notified) from the base station 100 (or notified (notified) via the base station 200). The control information receiving unit 301 outputs the received transmission control information to the transmission control unit 302. Here, each terminal 300 recognizes in advance a resource group that can be used by itself, and includes transmission control information for each resource group transmitted from the base station 100 (or relayed by the base station 200). The transmission control information corresponding to the resource group that can be used by the machine is received.

The transmission control unit 302 determines its own transmission control method based on the transmission control information input from the control information receiving unit 301. Then, the transmission control unit 302 controls the transmission baseband unit 304 and the RF unit 305 according to the determined transmission control method. Details of the transmission control process in the transmission control unit 302 will be described later.

Modulation section 303 modulates transmission data (uplink data) for another base station 200 (macro base station), and outputs the modulated transmission data to transmission baseband section 304.

The transmission baseband unit 304 performs transmission baseband processing on transmission data input from the modulation unit 303 in accordance with an instruction from the transmission control unit 302, and outputs the transmission data after transmission baseband processing to the RF unit 305. .

The RF unit 305 performs transmission radio processing (up-conversion, digital analog (D / A) conversion, etc.) on transmission data input from the transmission baseband unit 304 in accordance with an instruction from the transmission control unit 302, and transmits transmission radio. The processed transmission data is transmitted from the antenna 306.

In addition, here, the case where the transmission control information received by the terminal 300 (macro terminal) is mainly reported directly from the base station 100 (pico base station) has been described. However, the base station 100 notifies the other base station 200 of transmission control information in advance via a backhaul line (or a wireless line via a reception RF unit (not shown)), and the other base station 200 transmits it. The configuration of the terminal 300 is the same when reporting the control information to the terminal 300. That is, another base station 200 shown in FIG. 4 performs transmission processing on transmission control information from base station 100 in addition to transmission data (downlink data).

[Operations of Base Station 100, Other Base Station 200, and Terminal 300]
Operations of the base station 100, the other base station 200, and the terminal 300 configured as described above will be described.

[Determination of Resource Group Available to Terminal 300]
Terminals 300 are grouped into a plurality of groups in advance according to the amount of interference given to base station 100 by the terminal 300, that is, the degree of influence of each terminal 300 on the total interference in base station 100. For example, a plurality of terminals 300 having the same distance from the base station 100 are considered to have the same degree of influence on the interference sum in the base station 100. Therefore, as an example of grouping for the terminals 300, the plurality of terminals 300 are grouped into a plurality of groups according to the distance from the base station 100. For example, the distance between the base station 100 and the terminal 300 is measured using GPS (Global Positioning System).

Further, the means for grouping the terminals 300 is not limited to the means for using the distance between the base station 100 and the terminal 300, and other means described below may be used.
(1) Means using the received power of the transmission signal of the terminal 300 in the base station 100. In this means, the base station 100 (interfered station) receiving the interference groups the terminals 300 according to the reception power of the transmission signal of each terminal 300, and clearly shows the formed group to each terminal 300. .
(2) Means using the received power value of the base station 100 in the terminal 300. In this means, each terminal 300 measures the strength (or quality) of a downlink signal received from the base station 100, and determines a group to which the own device belongs according to the measured value. Since there is a strong correlation between the measured downlink signal strength and the interference that the own device gives to the base station 100 in the uplink channel, grouping using such a method is also effective.
(3) Means using an estimated value of the amount of interference given from the terminal 300 to the base station 100. In this means, each terminal 300 estimates the path loss from the intensity of the downlink signal received from the base station 100 and the transmission power information of the base station 100 (for example, information notified by the other base station 200 to the terminal 300). Then, the group to which the aircraft belongs should be determined according to the estimated path loss.

In this way, each terminal 300 is grouped in advance into a plurality of groups, and a resource group to be used by each terminal 300 is designated for each group.

[Generation of Transmission Control Information by Base Station 100]
Base station 100 groups resources to be used in advance into a plurality of groups (resource groups). In each resource group, transmission control is performed on interference information regarding the amount of interference received by the own station, which is an interfered station, in the uplink channel. Information is generated at regular time intervals. Specifically, the transmission control information generation unit 105 has a certain amount of interference (for example, the sum of interference power from the plurality of terminals 300) that the own device receives from the plurality of terminals 300 (hereinafter referred to as an interference threshold). ) Is generated as transmission control information.

Note that the interference threshold value may be a value set in advance in the specification, or a different value for each base station 100 may be used. For example, the maximum interference amount allowable in the base station 100 may be set as the interference threshold. Further, as described above, the amount of interference received by the base station 100 may be a total value of the amount of interference (interference power) received from the plurality of terminals 300, and the base station 100 does not necessarily receive information on the plurality of terminals 300. There is no need to hold it.

Thus, the transmission control information is generated based on the amount of interference received by the base station 100 (interfered station) from the terminal 300 (transmitting apparatus). Then, the base station 100 broadcasts the generated transmission control information to the plurality of terminals 300 as common transmission control information. The information amount of the transmission control information is 1 bit for each resource group.

[Transmission control by terminal 300]
Each terminal 300 uses the transmission control information corresponding to the resource group used by itself from among the transmission control information broadcast for each resource group from the base station 100 (or via another base station 200). The terminal 300 performs transmission control based on a “strategy” that each terminal 300 has uniquely.

The “strategy” is a correspondence relationship in which a transmission control policy of the terminal 300 is associated with each of a plurality of history pattern candidates of transmission control information (patterns of reception results of transmission control information for the past several times). In other words, “strategy” is mapped with what kind of action (transmission control policy) is performed when transmission control information (μ [k]: 1 or −1) at a certain time (k) is received. Can be represented by a table.

For example, a table representing “strategy” in a certain terminal 300 is shown in FIG. As illustrated in FIG. 6, each terminal 300 includes a strategy group including a plurality of different strategies (here, three strategies of strategy a, strategy b, and strategy c). In each strategy shown in FIG. 6, transmission control information (μ [k−1] and μ [k]) for the past two times from the base station 100 from the transmission control information received last time to the transmission control information received this time. A history pattern candidate (history length 2) of four types of transmission control information representing a reception result pattern is associated with a transmission control policy ("transmission +" or "transmission-"). In other words, each “strategy” is represented by a collection of correspondences between each of a plurality of history pattern candidates of transmission control information constituting a history pattern candidate group of transmission control information and a transmission control policy.

In FIG. 6, when the amount of interference received by base station 100 at time k (the sum of interference power from a plurality of terminals 300) exceeds the interference threshold, transmission control information μ [k] = 1, and time In k, when the amount of interference received by the base station 100 is within the interference threshold, the transmission control information μ [k] = − 1.

Also, in the transmission control policy, “transmission +” represents an operation for increasing the transmission of the terminal 300, that is, transmission control for actively transmitting the terminal 300. On the other hand, “transmission-” represents an operation for reducing the transmission of the terminal 300, that is, transmission control for passively transmitting the terminal 300. That is, the transmission control policy indicates whether the transmission (transmission opportunity) of the terminal 300 is increased or decreased.

For example, as transmission control corresponding to “transmission +” (transmission control for actively transmitting terminal 300), transmission control for increasing transmission power of terminal 300 (power control), transmission of downlink data for terminal 300 Transmission control for increasing the frequency (frequency of subframes in which downlink data is transmitted) (control in the time domain), transmission control for increasing the frequency band (frequency resource) used for transmission of the terminal 300 (control in the frequency domain) Alternatively, there is transmission control (control in the spatial domain) in which the terminal 300 performs transmission.

On the other hand, as transmission control corresponding to “transmission−” (operation opposite to “transmission +”, that is, transmission control in which transmission of terminal 300 is passively performed), transmission control for reducing transmission power of terminal 300 is performed. (Power control), transmission control for reducing downlink data transmission frequency of terminal 300 (frequency of subframes for transmitting downlink data) (control in time domain), frequency band used for transmission of terminal 300 ( There is transmission control (frequency domain control) for reducing (frequency resources) or transmission control (spatial domain control) in which terminal 300 does not perform transmission.

Further, a plurality of different strategies (strategy groups) that each terminal 300 has uniquely are generated in association with, for example, IDs unique to the terminals. That is, the contents of the strategy group (strategy a, strategy b, strategy c) shown in FIG. 6 (operations associated with the reception results of the transmission control information for the past two times) are different for each terminal 300.

Further, as shown in FIG. 6, each of the plurality of different strategies possessed by each terminal 300 has priority (priority a [k] for strategy a, priority b [k] for strategy b, priority for strategy c). c [k]) is set. The terminal 300 selects a strategy with a higher priority at each time.

Then, the transmission control unit 302 of each terminal 300 is identified from the history of the transmission control information received from the base station 100 (or via another base station 200) and the selected strategy (high priority strategy). Based on the transmission control policy (“transmission +” or “transmission−”). Specifically, assuming that a history pattern of transmission control information is represented by a predetermined number (for example, N, ie, history length = 2) of transmission control information patterns, the transmission control unit 302 has received this time. The priority of each strategy is updated based on the transmission control information, and history of N pieces of transmission control information from the transmission control information received (N-1) times before to the transmission control information received this time, and the priority Based on the control strategy specified by the high strategy, the transmission of its own device is controlled.

For example, in terminal 300 having the strategy group (history length = 2) shown in FIG. 6, transmission control information μ [k−1] = 1 at time k−1, and transmission control information μ [k] = − 1 at time k−1. A case where the priority a [k] of the strategy a is the highest among the strategies a to c at time k will be described.

In this case, as shown in FIG. 6, the transmission control unit 302 is associated with the history pattern candidate (μ [k−1] = 1, μ [k] = − 1) of the transmission control information in the strategy a. The transmission control policy “transmission +” is specified. Therefore, the transmission control unit 302 performs transmission control for increasing transmission of the terminal 300 (transmission control that actively performs transmission of the terminal 300) based on the specified transmission control policy “transmission +” at time k. .

Next, the transmission control unit 302 updates the priority of each of a plurality of different strategies based on the transmission control information transmitted from the base station 100. Specifically, each terminal 300 determines that transmission control based on the history pattern of transmission control information at time k-1 and time k (that is, the transmission control policy specified at time k) is correct from the viewpoint of the system. Is determined using transmission control information μ [k + 1] received at time k + 1.

For example, as shown in FIG. 6, the history pattern of the transmission control information is (μ [k−1] = 1, μ [k] = − 1), and the terminal 300 selects the strategy a at time k, as shown above. Then, a case will be described where transmission control information μ [k + 1] notified from base station 100 at the next timing (time k + 1) is −1. In this case, the terminal 300 determines that “when the history pattern of the transmission control information is (μ [k−1] = 1, μ [k] = − 1), the terminal 300 performs“ transmission + ”transmission control at time k. “It was correct to perform (transmission control for actively transmitting the terminal 300)”.

Therefore, the transmission control unit 302 has a strategy in which the transmission control policy associated with the history pattern candidate (μ [k−1] = 1, μ [k] = − 1) of the transmission control information is “transmission +”. Increase the priority of a certain amount. Conversely, the transmission control unit 302 has a transmission control policy “transmission−” associated with the history pattern candidate (μ [k−1] = 1, μ [k] = − 1) of the transmission control information. Reduce strategy priority by a certain amount. For example, in FIG. 6, the transmission control unit 302 increases the priority a [k + 1] of the strategy a actually selected at the time k by a certain amount, and the history pattern candidate (μ [k− The priority c [k + 1] of the strategy c whose transmission control policy associated with 1] = 1, μ [k] = − 1) is “transmission +” is also increased by a certain amount. On the other hand, in FIG. 6, the transmission control unit 302 sets the transmission control policy associated with the history pattern candidate (μ [k−1] = 1, μ [k] = − 1) of the transmission control information to “transmission- The priority b [k + 1] of the strategy b that is “is decreased by a certain amount.

In other words, the above operation is performed even though the base station 100 performs the transmission control in which the terminal 300 actively transmits the terminal 300 based on the strategy a (“transmission +” transmission control) at the time k. It was possible to maintain the result (μ [k + 1] = − 1) that the amount of interference at is less than the allowable value (interference threshold) ”. That is, at time k, the strategy a for the terminal 300 can be said to be effective for the purpose of “maximizing the transmission opportunity of the terminal 300 while suppressing interference with the base station 100”.

On the other hand, as shown in FIG. 6, when the history pattern of the transmission control information is (μ [k−1] = 1, μ [k] = − 1) and the terminal 300 selects the strategy a at time k, A case where the transmission control information μ [k + 1] notified from the base station 100 at the next timing (time k + 1) is 1 will be described. In this case, the terminal 300 determines that “when the history pattern of the transmission control information is (μ [k−1] = 1, μ [k] = − 1), the terminal 300 performs“ transmission + ”transmission control at time k. “It was wrong to perform (transmission control that actively transmits the terminal 300)”.

Therefore, the transmission control unit 302 has a strategy in which the transmission control policy associated with the history pattern candidate (μ [k−1] = 1, μ [k] = − 1) of the transmission control information is “transmission +”. Decrease the priority of by a certain amount. Conversely, the transmission control unit 302 has a transmission control policy “transmission−” associated with the history pattern candidate (μ [k−1] = 1, μ [k] = − 1) of the transmission control information. Increase strategy priority by a certain amount. For example, in FIG. 6, the transmission control unit 302 decreases the priority a [k + 1] of the strategy a actually selected at time k by a certain amount, and the history pattern candidate (μ [k− The priority c [k + 1] of the strategy c whose transmission control policy associated with 1] = 1, μ [k] = − 1) is “transmission +” is also decreased by a certain amount. On the other hand, in FIG. 6, the transmission control unit 302 sets the transmission control policy associated with the history pattern candidate (μ [k−1] = 1, μ [k] = − 1) of the transmission control information to “transmission- The priority b [k + 1] of the strategy b which is “is increased by a certain amount.

In other words, the above operation is partly caused by the fact that “the terminal 300 has performed transmission control that actively transmits the terminal 300 based on the strategy a (“ transmission + ”transmission control) at time k, It can be said that the amount of interference in the base station 100 exceeds the allowable value (interference threshold) (μ [k + 1] = 1) ”. That is, at time k, the strategy a for the terminal 300 is not effective for the purpose of “maximizing the transmission opportunity of the terminal 300 while suppressing interference with the base station 100” (incorrect selection). It can be said.

Then, the transmission control unit 302 of each terminal 300, at time k + 1 (not shown), the transmission control information history pattern (μ [k], μ [k + 1]) and the strategy (priority) selected at time k + 1. The transmission of the terminal 300 is controlled based on the transmission control policy specified by the high-level strategy. In this way, each terminal 300 sequentially performs the transmission control described above, and continues to update the priorities of a plurality of different strategies that each terminal has.

That is, each terminal 300 (macro terminal) keeps updating the priority of each strategy, thereby suppressing “interference with the base station 100 (pico base station) in each of a plurality of history pattern candidates of the transmission control information. We will identify strategies that include more transmission control policies that were effective for the purpose of maximizing the transmission opportunity of the device. As a result, the network is finally configured in an autonomous and distributed manner so that each terminal 300 uses a unique strategy (a strategy suitable for each terminal 300).

Here, the above operation of the terminal 300 will be described from another viewpoint as follows.

The target of the transmission control of the terminal 300 in the present embodiment is “maximizing the transmission opportunity of the terminal 300 while keeping the interference value given to the base station 100 below a certain value (allowable value)”. In other words, the terminal 300 performs transmission control such that “the transmission opportunity of the terminal 300 is maximized while satisfying the constraint condition regarding interference in the base station 100 (that is, interference on the uplink channel)”.

On the other hand, compared with the above operation of terminal 300 in the present embodiment, it is different in “a point in which a plurality of terminals are grouped according to the degree of interference that the terminal gives to the base station”. For example, the ability to effectively use a technique based on the Minority Game (MG) concept for the transmission control of “maximizing the transmission opportunity of its own device while satisfying the constraint condition regarding a certain interference” , "Koji Yamamoto, Kazuya Kimura, Eiichi Murata, Susumu Yoshida," Characteristic Evaluation of Self-Organized Interference Control Method Using Minority Games ", IEICE Technical Report, SR2009-106, March 2010 (K .Yamamoto, K.Kimura, H.Murata, S.Yoshida, oshi "Performance Evaluation of Minority Game-based Self-organized Interference Management," IEICE Technical Report, SR2009-106, March 2010) ".

As described above, in the present embodiment, the transmission control of each terminal 300 (macro terminal) is based on the Minority Game concept as described in the above document. Thus, transmission control can be effectively performed from the viewpoint of the system. Specifically, each terminal 300 (macro terminal) updates the priority of each unique strategy group (a plurality of different strategies) based on the transmission control information, and autonomously distributed transmission control ( Interference control based on Minority Game concept). Thereby, for example, when performing transmission control of a plurality of macro terminals in a heterogeneous network, it is possible to perform appropriate transmission control for each macro terminal while suppressing an increase in the complexity of the entire system. .

In addition, in a minority game, the more the effect on the result (the amount of interference given to the base station 100) is the same, the more the “method based on the concept of the minority game” is performed, There is a feature that it is possible to further reduce the amount of interference on the interfered side while further increasing the transmission probability on the transmitting side.

The above features can also be read from, for example, the computer simulation result shown in FIG. As a result of the computer simulation shown in FIG. 7, as an example of transmission control, the macro terminal (terminal 300) applies a minority game (game theory) to “transmit (transmit +)” or “do not transmit (transmit −). Assuming that two-choice transmission control is performed, a state after a sufficient time has elapsed and the strategy in each macro terminal has converged is shown. FIG. 7 shows each state when the number of macro terminals is constant 100 and the variation in distance from the macro terminal to the pico base station is changed.

In FIG. 7, the horizontal axis indicates the outage probability in the pico base station (base station 100) (that is, the rate at which the amount of interference exceeds the allowable value in the base station 100), and the vertical axis indicates the transmission probability of the macro terminal (that is, The rate at which the terminal 300 is allowed to transmit). That is, in FIG. 7, the better the characteristic is, the higher the upper left (the characteristic that the outage probability is low and the transmission probability is high).

As shown in FIG. 7, it can be seen that the greater the variation in the distance from the macro terminal (terminal 300) to the pico base station (base station 100), the more the characteristics after the strategy converges. That is, as shown in FIG. 7, the smaller the variation in the distance from the macro terminal (terminal 300) to the pico base station (base station 100), that is, the distance from the pico base station becomes a plurality of macro terminals (100 It can be seen that the more the same degree between the macro terminals), the better the characteristics after the strategy converges.

That is, as in the present embodiment, according to the distance to the base station 100, a plurality of terminals 300 are grouped into a plurality of groups, and a minority game is applied to each group, thereby comparing with a case where no grouping is performed. This makes it easier to obtain the characteristics (effects) of the minority game described above.

Furthermore, the characteristics of the above-mentioned minority game can also be read from the computer simulation results shown in FIG. The computer simulation shown in FIG. 8 shows the characteristics (triangle mark) when the macro terminals are grouped into two groups at an optimum distance, and transmission control is performed by applying a minority game for each group. The characteristic (circle) when not grouping is shown. That is, when grouping, a plurality of terminals 300 whose distance to the base station 100 is equal to or greater than a certain threshold (optimum distance) are set as the first group, and the distance to the base station 100 is less than the threshold (optimum distance). A plurality of terminals 300 are defined as the second group. And the transmission control which applied the minority game for every group is performed, using a different resource group by each of a 1st group and a 2nd group. However, the “optimum distance” here is a distance that bisects all the terminals 300 when the number of resource groups allocated to the first group is the same as the number of resource groups allocated to the second group. Become.

In FIG. 8, the horizontal axis indicates the dispersion value from the target interference amount at the pico base station (base station 100), and the vertical axis indicates the transmission probability of the macro terminal (that is, the terminal 300 may transmit). Ratio). Here, the smaller the variance value of the target interference amount, the better the convergence characteristic of the actual interference amount with respect to the target interference amount at the pico base station. That is, in FIG. 8, the better the state is, the closer to the upper left (characteristic that the dispersion value is low and the transmission probability is high).

As shown in FIG. 8, when the macro terminals are grouped into two groups at an optimum distance, better convergence characteristics (lower dispersion value) and higher transmission are obtained than when the macro terminals are not grouped. Probability is shown.

As described above, in this embodiment, each terminal 300 (macro terminal) performs transmission control based on the concept of minority game (Minority よ う な Game) as shown in the above document, for example, randomly transmitting Compared with the case where control is performed, transmission control can be effectively performed from the viewpoint of the system. Specifically, each terminal 300 (macro terminal) updates the priority of its own strategy group (a plurality of different strategies) based on the transmission control information, and each terminal 300 (macro terminal) performs independent and distributed transmission control ( Interference control based on the concept of minority games). Thereby, for example, when performing transmission control of a plurality of macro terminals in a heterogeneous network, it is possible to perform appropriate transmission control for each macro terminal while suppressing an increase in the complexity of the entire system. .

Further, in the present embodiment, a plurality of terminals 300 are assigned to a plurality of terminals 300 (macro terminals) in accordance with the magnitude of influence (degree of influence of interference) on the amount of interference in base station 100 (pico base station). Group into groups (resource groups). Then, on the premise that different resources are used for each group, the base station 100 generates transmission control information for each group, and the terminal 300 performs transmission control using transmission control information corresponding to the group to which the mobile station belongs. I do. As a result, the effect obtained by applying the minority game (that is, the effect of suppressing the amount of interference on the interfered side to be smaller while increasing the transmission probability on the transmission side) is compared to the case of not grouping. , Get bigger.

Also, the information amount of the transmission control information of each resource group (information common to all terminals 300 belonging to the same group) notified from the base station 100 to the terminal 300 is 1 bit. That is, in each group, the amount of transmission control information from base station 100 (pico base station) to terminal 300 (macro terminal) can be minimized (1 bit). Further, the base station 100 (pico base station) only needs to measure the total interference (total interference power) from the plurality of terminals 300 (macro terminals), and minimizes the measurement load (measurement load) at the base station 100. To the limit.

As described above, according to the present embodiment, when performing macro terminal transmission control, an increase in the amount of transmission control information from a pico base station to a macro base station or a macro terminal is suppressed, and appropriate for each macro terminal. Transmission control can be performed.

In the present embodiment, a case has been described in which the transmission opportunity (or transmission power, transmission band, etc.) of the macro terminal is maximized while suppressing uplink interference from the macro terminal in the pico base station. However, this embodiment can also be applied to the following cases.
(1) A case where the transmission opportunity of the pico terminal is maximized while suppressing uplink interference from the pico terminal in the macro base station. In this case, the macro base station generates transmission control information, and the pico terminal performs transmission control using a minority game.
(2) The case of maximizing the transmission opportunity of the macro base station while suppressing downlink interference from the macro base station in the pico terminal. In this case, the pico terminal generates transmission control information, and the macro base station performs transmission control using a minority game.
(3) A case where the transmission opportunity of the pico base station is maximized while suppressing downlink interference from the pico base station in the macro terminal. In this case, the macro terminal generates transmission control information, and the pico base station performs transmission control using a minority game.

However, the above-described device grouping effect can be obtained more when there are more interference sources (transmitting devices according to the present embodiment). For this reason, considering the situation where many terminals are connected to one base station, the effect of device grouping is that when downlink interference control is performed (that is, the base station (macro base station or pico base It is considered that when uplink interference control is performed (that is, when grouping is applied to a terminal (macro terminal or pico terminal)) is larger than when grouping is applied to a station). It is done.

[Other embodiments]
(1) In the above embodiment, the number of strategies (three in FIG. 6) of each terminal 300 may be adaptively changed.

(2) Further, in the present embodiment, a case has been described in which transmission control information is generated in accordance with the total interference received by base station 100. For example, TDMA (Time Division Multiple Access) and FDMA (Frequency Division Multiple Access) are used. In the case where a plurality of channels are explicitly divided as in the above, the total sum of interference is the total sum of interference amounts in each resource group. In addition, when channels are not explicitly divided, such as OFDMA (Orthogonal Frequency Division Multiple Access) and SC-FDMA (Single Carrier-Frequency Frequency Division Multiple Access), the total interference is a resource that can be used by each group. It is a value obtained by integrating the amount of interference within (that is, the frequency (subcarrier) range).

(3) In the above embodiment, the same amount of resource group is allocated to each of the “groups formed according to the distance to the base station 100” (that is, the distance that bisects all the terminals 300 is However, it is also possible to allocate a different amount of resource group to each group. In this case, the above-mentioned “optimum distance” is the resource for each group. Varies according to the group quota. For example, if more resources are assigned to the first group than the second group, a threshold (that is, “optimum distance”) is set so that more terminals belong to the first group. Thus, the plurality of terminals 300 may be grouped.

(4) Also, in the above embodiment, the so-called Weighted, in which the ratio of the transmission control policies (“transmission +” and “transmission−”) associated with the history pattern candidates of each transmission control information is different for each strategy You may apply table. In this case, the weighted table is set so that the transmission control (transmission control policy) associated with the history pattern of the transmission control information is biased to one (either “transmission +” or “transmission −”). Is a table to be played. An example in which Weighted table is applied to the strategy is shown in FIG. In the strategy c shown in FIG. 9, among the four types of history pattern candidates of the transmission control information, “transmission +” is associated with three types of history pattern candidates, and “transmission−” is associated with the remaining one type of history pattern. It is associated. That is, the strategy c illustrated in FIG. 9 is a strategy (Weighted table) in which a transmission control policy biased toward “transmission +” is set.

For example, in the terminal 300 that is far from the base station 100 and the terminal 300 that is close to the base station 100, even if the former transmits signals more actively, the base station It is considered that the amount of interference at 100 does not increase. For this reason, it is preferable to apply, for example, a weighted table that is biased toward “transmission +” like strategy c shown in FIG. 9 to a group of terminals to which the former (terminal 300 far from the base station 100) belongs. It is.

(5) Further, in the above embodiment, a case has been described in which the base station 100 sets the notification transmission control information to the terminal 300 to 1 bit for each resource group. However, the transmission control information notified by the base station 100 is not limited to 1 bit for each resource group, and may be expressed by 2 bits or more. Thereby, the amount of interference in the base station 100 can be fed back more accurately.

(6) Although cases have been described with the above embodiments as examples where the present invention is configured by hardware, the present invention can also be realized by software in conjunction with hardware.

Further, each functional block used in the description of the above embodiment is typically realized as an LSI which is an integrated circuit. These may be individually made into one chip, or may be made into one chip so as to include a part or all of them. Although referred to as LSI here, it may be referred to as IC, system LSI, super LSI, or ultra LSI depending on the degree of integration.

Further, the method of circuit integration is not limited to LSI, and implementation with a dedicated circuit or a general-purpose processor is also possible. An FPGA (Field Programmable Gate Array) that can be programmed after manufacturing the LSI or a reconfigurable processor that can reconfigure the connection and setting of circuit cells inside the LSI may be used.

Furthermore, if integrated circuit technology that replaces LSI emerges as a result of progress in semiconductor technology or other derived technology, it is naturally possible to integrate functional blocks using this technology. Biotechnology can be applied.

The disclosure of the specification, drawings and abstract contained in the Japanese application of Japanese Patent Application No. 2010-284618 filed on Dec. 21, 2010 is incorporated herein by reference.

The present invention is useful for a macro base station / macro terminal, a pico base station / pico terminal, a femto base station / femto terminal, and the like introduced into a heterogeneous network.

100 base station 101, 204, 306 antenna 102, 203, 305 RF unit 103 reception baseband unit 104 interference measurement unit 105 transmission control information generation unit 106, 201, 303 modulation unit 107, 202, 304 transmission baseband unit 200 other Base station 300 Terminal 301 Control information receiving unit 302 Transmission control unit

Claims (12)

1. A receiver for receiving control information related to interference in the interfered station;
   A correspondence relationship in which a control guideline for transmission is associated with each of the plurality of history patterns of the control information, and the priority of each of the plurality of different correspondence relationships is updated based on the control information, A control unit for controlling transmission based on the control guideline specified from the history of the received control information and the correspondence relationship having a high priority;
   A transmitter.
2. A plurality of the transmitting devices are grouped into a plurality of groups;
   The control information is generated for each group.
   The transmission device according to claim 1.
3. A plurality of the transmission devices are grouped into a plurality of groups according to the degree of influence of interference on the interfered station,
   The control information is generated for each group.
   The transmission device according to claim 1.
4. A plurality of the transmission devices are grouped into a plurality of groups according to the distance to the interfered station,
   The control information is generated for each group.
   The transmission device according to claim 1.
5. The control information is generated based on the amount of interference received by the interfered station from the transmission device.
   The transmission device according to claim 1.
6. The control information indicates whether or not the interference amount is within a predetermined value.
   The transmission device according to claim 5.
7. The control information is 1 bit.
   The transmission device according to claim 1.
8. The control guidelines indicate whether to increase or decrease transmissions;
   The transmission device according to claim 1.
9. The control guideline indicates whether to increase or decrease transmission power, increase or decrease time resources used for transmission, increase or decrease frequency resources used for transmission, or perform transmission.
   The transmission device according to claim 1.
10. The interfered station is a base station.
    The transmission device according to claim 1.
11. A mobile station comprising the transmission device according to any one of claims 1 to 10.
12. Receive control information related to interference at the interfered station,
    A correspondence relationship in which a control guideline for transmission is associated with each of the plurality of history patterns of the control information, and the priority of each of the plurality of different correspondence relationships is updated based on the control information, Control transmission based on the control guideline specified from the received history of the control information and the correspondence relationship with the high priority.
    Transmission control method.

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