KR20170014189A - Transmission power of the base station control method and apparatus - Google Patents

Abstract

The present invention relates to a method and an apparatus for controlling transmission power of a base station. According to the present invention, in a method of allocating power to a terminal in a base station interlocking with a plurality of terminals, the method comprises the following steps: receiving, form the plurality of terminals, information including a reception sensitivity with respect to a second transmission power lower than a first transmission power which is the maximum available transmission power of the base station; using the reception sensitivity to recognize a cell-edge terminal with respect to each of the plurality of terminals; and changing a first modulation mode into a second modulation mode robust to noise and interference with respect to only the recognized cell-edge terminal, and allocating the power equivalent to the difference between the first transmission power and the second transmission power.

Description

[0001] The present invention relates to a transmission power control method and apparatus for a base station,

The present invention relates to a transmission power control method and apparatus for a base station, and more particularly, to a method and apparatus for adaptively controlling a modulation scheme and a transmission power based on channel quality of a terminal in a cell.

Recently, with the development of mobile communication technology and the spread of various portable communication equipments, many users can easily and quickly use multimedia services through the Internet in indoor and outdoor. In particular, as video services such as video streaming become common, mobile traffic is explosively increasing. In order to cope with such increasing traffic, it is required to maximize the channel capacity for using resources such as limited power and frequency band as efficiently as possible for each transmission medium. Various modulation and demodulation techniques are being used to efficiently use these limited resources.

In the case of a wired network, high-efficiency QAM modulation and demodulation techniques are widely used because the channel characteristics are stable. In general, a wireless network is not stable compared to a wired channel due to a fading effect due to a multipath or Doppler effect. The modulation and demodulation scheme of FSK and PSK series that transmit 1 to 2 bits per each is used, and multi-level modulation and demodulation methods such as 16-QAM, 64-QAM and 256-QAM are adopted in the wireless network between the base station and the subscriber, .

Meanwhile, with the use of various modulation and demodulation schemes, the base station controls the cell coverage of the base station by using a lot of power for high-speed and high-capacity data communication with the terminal.

The cell coverage is changed according to the transmission power of the base station. When the transmission is performed with a large transmission power, the cell coverage is increased but a lot of power is consumed. When the transmission power is reduced, the power consumption is decreased, but the cell coverage is decreased. The cell edge user located at the edge of the cell has a problem that the communication quality is deteriorated.

It is an object of the present invention to reduce the transmission power of a base station, thereby saving power and reducing the transmission power of a terminal (Cell-Edge User) located at a cell edge Thereby providing a method for ensuring quality.

It is another object of the present invention to provide a base station that communicates with a terminal using a power lower than the maximum transmission power.

It is another object of the present invention to provide a terminal that changes a modulation scheme according to reception sensitivity from a base station and communicates data by increasing power only to a terminal located at a cell edge, thereby ensuring communication quality.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, unless further departing from the spirit and scope of the invention as defined by the appended claims. It will be possible.

According to an aspect of the present invention, there is provided a method for allocating power to a terminal in a base station interworking with a plurality of terminals, the method comprising: receiving, from a plurality of terminals, Receiving information including a reception sensitivity for a second transmission power lower than the power; Identifying a terminal located at a cell edge with respect to each of the plurality of terminals using the reception sensitivity; And changing a first modulation scheme to a second modulation scheme resistant to noise and interference only for a terminal located at an edge of the identified cell and allocating power equal to the difference between the first transmission power and the second transmission power; . ≪ / RTI >

According to an exemplary embodiment, the reception sensitivity may include at least one of a reference signal received power (RSRP), a received signal strength indicator (RSSI), and a channel quality indicator (CQI).

According to the embodiment, the first modulation scheme may have a larger number of symbols to be transmitted per unit time than the second modulation scheme.

According to an embodiment, the first modulation scheme may be one of 16QAM (Quadrature Amplitude Modulation), 64QAM, and 256QAM, and the second modulation scheme may be Quadrature Phase Shift Keying (QPSK).

According to an embodiment, the step of allocating power equal to the difference between the first transmission power and the second transmission power may differentially allocate power according to the reception sensitivity of each of the plurality of terminals.

According to an embodiment of the present invention, the step of identifying a terminal located at a cell edge with respect to each of the plurality of terminals using the reception sensitivity may include the step of, when the reception sensitivity has a value lower than a predetermined threshold value, .

According to an embodiment, the information including the reception sensitivity may be periodically received.

According to an embodiment of the present invention, the step of identifying a terminal located at an edge of a cell with respect to each of the plurality of terminals using the reception sensitivity may include the step of, when a predetermined number of averages has a value lower than a predetermined threshold, It can be identified by the terminal.

Also, the base station interworking with a plurality of terminals according to an embodiment of the present invention may transmit information including reception sensitivity to a second transmission power lower than the first transmission power, which is the maximum transmission power of the base station, from the plurality of terminals A communication unit for receiving; A cell edge user identification unit for identifying a terminal located at a cell edge with respect to each of the plurality of terminals using the reception sensitivity; A modulation scheme changing unit that changes the first modulation scheme only to the edge users to a second modulation scheme that is strong against noise and interference; A transmission power adjustment unit that allocates only the edge user a power equal to the difference between the first transmission power and the second transmission power; . ≪ / RTI >

According to an exemplary embodiment, the reception sensitivity may include at least one of a reference signal received power (RSRP), a received signal strength indicator (RSSI), and a channel quality indicator (CQI).

According to the embodiment, the first modulation scheme may have a larger number of symbols to be transmitted per unit time than the second modulation scheme.

According to an embodiment, the first modulation scheme may be one of 16QAM (Quadrature Amplitude Modulation), 64QAM, and 256QAM, and the second modulation scheme may be Quadrature Phase Shift Keying (QPSK).

According to an embodiment, the step of allocating power equal to the difference between the first transmission power and the second transmission power may differentially allocate power according to the reception sensitivity of each of the plurality of terminals.

According to an embodiment, when the reception sensitivity has a value lower than a preset threshold value, the cell edge user identification unit can identify the terminal located at a cell edge.

According to an embodiment, the information including the reception sensitivity may be periodically received.

According to an embodiment, the cell edge user identification unit can identify a cell located at a cell edge when the average value of a certain number of times has a value lower than a preset threshold value.

In addition, a terminal interworking with a base station according to an embodiment of the present invention includes a reception sensitivity calculating unit for calculating reception sensitivity for a second transmission power lower than a first transmission power, which is a maximum transmission power of the base station; A wireless communication unit for transmitting information including the reception sensitivity; A cell edge user recognition unit for recognizing whether the terminal is located at a cell edge using the reception sensitivity; A modulation scheme switching unit that changes a first modulation scheme to a second modulation scheme that is strong against noise and interference when the MS is recognized as a terminal located at the edge of the cell; . ≪ / RTI >

According to an exemplary embodiment, the reception sensitivity may include at least one of a reference signal received power (RSRP), a received signal strength indicator (RSSI), and a channel quality indicator (CQI).

According to the embodiment, the first modulation scheme may have a larger number of symbols to be transmitted per unit time than the second modulation scheme.

According to an embodiment, the first modulation scheme may be one of 16QAM (Quadrature Amplitude Modulation), 64QAM, and 256QAM, and the second modulation scheme may be Quadrature Phase Shift Keying (QPSK).

Effects of the energy saving and accordingly the method and apparatus for securing the quality of the cell edge user by reducing the transmission power of the base station according to the present invention will be described as follows.

First, the present invention can save the power of the base station by using the transmission power lower than the maximum transmission power of the base station.

Second, by using transmission power lower than the maximum transmission power of the base station, the present invention can reduce interference and noise to the terminals in the nearby base station.

Third, the present invention utilizes modulation of interference and noise selectively only for a terminal located at a cell edge by using the reception sensitivity of the terminal, thereby ensuring a high communication quality for a terminal located at a cell edge.

The effects obtained by the present invention are not limited to the above-mentioned effects, and other effects not mentioned can be clearly understood by those skilled in the art from the following description will be.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. It is to be understood, however, that the technical features of the present invention are not limited to the specific drawings, and the features disclosed in the drawings may be combined with each other to constitute a new embodiment.
1 is a configuration diagram of a transmission power reduction system according to an embodiment of the present invention.
2 is a flowchart of a transmit power reduction method in accordance with an embodiment of the present invention.
FIG. 3 is a flowchart of a transmission power reduction method applying a modulation scheme to QPSK as a concrete example of FIG. 2. FIG.
4 is a configuration diagram of a base station according to an embodiment of the present invention.
5 is a configuration diagram of a terminal according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an apparatus and various methods to which embodiments of the present invention are applied will be described in detail with reference to the drawings. The suffix "module" and " part "for the components used in the following description are given or mixed in consideration of ease of specification, and do not have their own meaning or role.

In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

1 is a configuration diagram of a transmission power reduction system according to an embodiment of the present invention.

Referring to FIG. 1, a transmission power reduction system 1000 includes a base station 100 and a terminal 200.

The base station 100 transmits a resource allocation and transmission format of a downlink-shared channel (DL-SCH), a resource allocation of an uplink shared channel (UL-SCH), and the like, through a PHYSICAL CHANNEL such as a physical downlink control channel (PDCCH) Resource allocation for an upper layer control message such as paging information on a paging channel (PCH), system information on a DL-SCH, random access response transmitted on a physical downlink shared channel (PDSCH) And sets a control for exchanging data with the terminal 200 by allocating a traffic channel such as a PDSCH by exchanging control signals such as a set of transmission power control commands for individual UEs in the group.

The UE 200 may transmit uplink control information to the base station 100 through a physical uplink control channel (PUCCH). The uplink control information transmitted on the PUCCH includes a hybrid automatic repeat request (HARQ) acknowledgment / non-acknowledgment (NACK) / non-acknowledgment (NACK) for informing the base station 100 of an error on downlink traffic, A channel quality indicator (CQI) indicating an uplink radio resource allocation request, an SR (scheduling request) requesting uplink radio resource allocation, and the like.

In other words, the base station 100 and the terminal 200 can control transmission and reception power of the downlink and uplink through the control channel.

2 is a flowchart of a transmit power reduction method in accordance with an embodiment of the present invention.

2, the base station 100 can exchange control information with a plurality of terminals 200 with a transmission power lower than the maximum transmission power. The plurality of terminals 200 transmits information including the reception sensitivity through the PUCCH to the base station 100 (S310).

The location of the terminal 200 is flexible and the surrounding environment can be continuously changed due to the characteristics of the wireless network, so that the terminal 200 can periodically transmit the information including the reception sensitivity.

The reception sensitivity may be at least one of Reference Signal Received Power (RSRP), Received Signal Strength Indicator (RSSI), and Channel Quality Indicator (CQI).

The RSSI is the power of the entire signal passed through a Squared Root Raised Cosine (SRRC) filter, which is a pulse shaping filter, and is measured in dBm to be reported, and the point measured is the connector of the antenna.

The meaning of reference signal received power (RSRP) refers to the power of a reference signal received at the terminal. The unit of this measure is also dBm and the point to be measured is the connector of the antenna.

The channel quality indicator (CQI) measures the radio channel quality at a location where the terminal 200 itself is located, and transmits the measured CQI to the base station 100. The base station 100 uses the measured CQI to control the modulation scheme and transmission power Information. The CQI information includes a signal-to-noise ratio (SNR), a signal-to-interference-plus-noise ratio (SINR), a carrier-to- , Or Carrier-to-Interference-plus-Noise-Ratio (CINR)) in a predetermined bit (e.g., 5 bits or 4 bits).

The base station 100 determines whether the terminal 200 located at the edge of the cell or the terminal 200 located in the shaded area is used for each of the plurality of terminals 200 by using the reception sensitivity of the message received from the terminal 200. [ (Step S320).

For example, the base station 100 may determine the terminal 200 having a value lower than a predetermined threshold value of the reception sensitivity as the terminal 200 located at the cell edge. The threshold value can be set by the manager of the base station 100.

Also, the base station 100 may periodically receive information including the reception sensitivity from the terminal 200. Even if the average value of the predetermined number of times is lower than a predetermined threshold value, the base station 100 may identify the terminal 200 located at the edge of the cell .

For example, when the user of the terminal 200 has boarded the elevator, in order to identify the reception sensitivity inside the elevator and the reception sensitivity at the terminal 200 located at the edge of the cell, a predetermined number of reception sensitivities The average value can be used to identify this.

As a result of the determination by the base station 100, the base station 100 selectively changes the modulation scheme of the base station 100 to be strong against noise and interference only to the base station 200 determined to be the mobile station 200 located at the edge of the cell, The transmission power is further amplified for the transmission power lower than the maximum transmission power (S330).

The base station 100 can allocate the power according to the reception sensitivity of each of the plurality of terminals 200 by amplifying and allocating the transmission power to each of the terminals 200 located at the edge of the cell.

For example, when the terminal 1 and the terminal 2 are all identified as the terminal 200 located at the edge of the cell and the CQI of the terminal 2 is larger than the CQI of the terminal 1, 2 can be allocated.

Amplifying the transmission power to the terminal 200 located at the edge of the cell and using a modulation method stronger against noise and interference is to ensure communication quality.

FIG. 3 is a flowchart of a transmission power reduction method applying a modulation scheme to QPSK as a concrete example of FIG. 2. FIG.

Referring to FIG. 3, the base station 100 can be connected to a plurality of terminals 200 using transmission power lower than the maximum transmission power (S410), thereby saving power.

The plurality of terminals 200 transmit the information including the reception sensitivity to the base station 100 through the signal received through the transmission power lower than the maximum transmission power (S420).

The base station 100 determines whether it is the terminal 200 located at the cell edge based on the reception sensitivity included in the message (S430).

The base station 100 changes the modulation scheme of the terminal 200 determined as the terminal 200 located at the edge of the cell to the QPSK scheme which is more resistant to noise and interference than the QAM scheme and amplifies the transmission power.

By using the transmission power lower than the maximum transmission power, power equal to the maximum transmission power can be amplified to the terminal 200 determined as the terminal 200 located at the edge of the cell.

For example, when the maximum transmission power of the base station 100 is 2X60 (W) and the transmission power is 2X40 (W), the base station 100 transmits the power (2X20 (W) To the terminal 200 located in the terminal 200.

Regarding the modulation scheme, both the base station 100 and the terminal 200 modulate the data before transmitting the data. There are many different types of modulation schemes including, for example, binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), quadrature amplitude modulation (QAM), and pulse amplitude modulation (PAM). Each of these modulation schemes is preferred for certain types of transmissions. Moreover, implementations of each of these schemes may require different hardware configurations within base station 100 or terminal 200 implementing these schemes.

Quadrature phase shift keying (QPSK) is a technique for transmitting a transmission signal of two values (0 or 1) to be transmitted as one of phase shift keying (PSK) in accordance with two phases of 0 phase and π phase of a carrier, (BPSK: binary PSK), two bits of 0 and 1 of digital signals of two values are collected and transmitted in correspondence with four phases of a carrier wave.

QAM (Quadrature Amplitude Modulation) is a type of multi-level modulation that is a type of digital modulation and is a modulation scheme that uses both the amplitude and phase of a carrier wave. The QAM scheme includes, but is not limited to, higher order modulation schemes including 16QAM, 64QAM, 256QAM.

4 is a configuration diagram of a base station according to an embodiment of the present invention.

The base station 100 may include a communication unit 110, a cell edge user determination unit 120, a cell edge user determination unit 130, and a modulation scheme changing unit 140. The components shown in FIG. 4 are not essential, and the base station 100 having more or fewer components may be implemented.

Hereinafter, the components will be described in detail.

The communication unit 110 can transmit and receive control signals and data signals to and from a plurality of terminals 200. [ In one embodiment, the base station 100 may receive information including reception sensitivity for a second transmission power that is lower than the first transmission power, which is the maximum transmission power of the base station 100. [

The control signal is described in Fig. 1, and the reception sensitivity is described in Fig.

The cell edge user determination unit 120 determines whether each of the plurality of terminals 200 is a terminal 200 located at a cell edge using the reception sensitivity.

The cell edge user determination unit 130 can control to amplify the transmission power lower than the maximum transmission power only for the terminal 200 located at the cell edge.

The modulation scheme changing unit 140 can change the modulation scheme that is resistant to noise and interference only to the terminal 200 located at the cell edge.

AMC (Adaptive Modulation and Coding) is related to the modulation scheme change.

AMC is a technology that changes the modulation method and coding according to the wireless environment for high-speed data transmission. The terminal 200 reports the radio environment to the base station 100 through the CQI (power control is RSSI), and the base station 100 transmits data by applying a proper modulation scheme and coding.

For example, if the communication environment is good, a 4/4 coding rate is applied to the 64QAM modulation scheme, and if the communication environment is poor, the 1/4 coding rate is applied to the QPSK modulation. In the intermediate case, a 2/4 coding rate is applied to 16QAM.

When the terminal 200 reports the radio environment to the base station 100 through the CQI as in the case of controlling the transmission power, the base station 100 selects the modulation scheme and the coding rate based on the information of the CQI.

 5 is a configuration diagram of a terminal according to an embodiment of the present invention.

The terminal 200 may include a wireless communication unit 210, a reception sensitivity calculation unit 220, a cell edge user recognition unit 230, and a modulation scheme switching unit 240. The components shown in FIG. 5 are not essential, so that the terminal 200 having more or fewer components may be implemented.

Hereinafter, the components will be described in detail.

The wireless communication unit 210 can transmit and receive a control signal and a data signal to and from the base station 100. In one embodiment, the base station 100 transmits information including reception sensitivity.

The reception sensitivity calculating unit 220 calculates the reception sensitivity for the second transmission power lower than the first transmission power which is the maximum transmission power of the base station 100. [ The calculation of the reception sensitivity is shown in Fig.

The cell edge user recognition unit 230 recognizes whether the terminal 200 itself is the terminal 200 located at the cell edge using the reception sensitivity.

The modulation scheme switching unit 240 changes the modulation scheme of the terminal 200 in accordance with the modulation scheme to be changed by the base station 100 when recognizing the terminal 200 as the terminal 200 located at the edge of the cell .

It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof.

Accordingly, the above description should not be construed in a limiting sense in all respects and should be considered illustrative. The scope of the present invention should be determined by rational interpretation of the appended claims, and all changes within the scope of equivalents of the present invention are included in the scope of the present invention.

100: base station
200: terminal
110:
120: Transmission power adjustment unit
130: Cell edge user determination unit
140: Modulation method changing section
210:
220: reception sensitivity calculation unit
230: Cell edge user recognition unit
240: modulation method switching section

Claims (20)

A method for allocating power to a terminal in a base station interworking with a plurality of terminals,
Receiving information including reception sensitivity for a second transmission power lower than a first transmission power which is an available maximum transmission power of the base station from the plurality of terminals;
Identifying a terminal located at a cell edge with respect to each of the plurality of terminals using the reception sensitivity; And
Changing a first modulation scheme to a second modulation scheme resistant to noise and interference only for a terminal located at the cell edge identified; allocating power equal to the difference between the first transmission power and the second transmission power;
/ RTI > The method according to claim 1,
The reception sensitivity may be expressed as:
(RSRP), a received signal strength indicator (RSSI), and a channel quality indicator (CQI). The method according to claim 1,
Wherein the first modulation scheme has a larger number of symbols to be transmitted per unit time than the second modulation scheme. The method according to claim 1,
Wherein the first modulation scheme is one of 16QAM (Quadrature Amplitude Modulation), 64QAM, and 256QAM, and the second modulation scheme is Quadrature Phase Shift Keying (QPSK). The method according to claim 1,
Wherein the step of allocating power equal to the difference between the first transmission power and the second transmission power comprises:
The power is differentially allocated according to the reception sensitivity of each of the plurality of terminals
Power allocation method. The method according to claim 1,
Wherein the step of identifying a terminal located at a cell edge with respect to each of the plurality of terminals using the reception sensitivity comprises:
When the reception sensitivity has a value lower than a preset threshold value,
Power allocation method. The method according to claim 1,
And the information including the reception sensitivity is periodically received. 8. The method of claim 7,
Wherein the step of identifying a terminal located at a cell edge with respect to each of the plurality of terminals using the reception sensitivity comprises:
When the average value of the predetermined number of times has a value lower than a preset threshold value,
Power allocation method. A base station interworking with a plurality of terminals,
A communication unit for receiving information including reception sensitivity for a second transmission power lower than a first transmission power which is a maximum transmission power of the base station from the plurality of terminals;
A cell edge user identification unit for identifying a terminal located at a cell edge with respect to each of the plurality of terminals using the reception sensitivity;
A modulation scheme changing unit that changes the first modulation scheme only to the edge users to a second modulation scheme that is strong against noise and interference;
A transmission power adjustment unit that allocates only the edge user a power equal to the difference between the first transmission power and the second transmission power;
/ RTI > 10. The method of claim 9,
The reception sensitivity may be expressed as:
(RSRP), a received signal strength indicator (RSSI), and a channel quality indicator (CQI). 10. The method of claim 9,
Wherein the first modulation scheme has a larger number of symbols to be transmitted per unit time than the second modulation scheme. 10. The method of claim 9,
The first modulation scheme may be one of 16QAM (Quadrature Amplitude Modulation), 64QAM, and 256QAM, and the second modulation scheme is Quadrature Phase Shift Keying (QPSK). 10. The method of claim 9,
Wherein the step of allocating power equal to the difference between the first transmission power and the second transmission power comprises:
The power is differentially allocated according to the reception sensitivity of each of the plurality of terminals
Base station. 10. The method of claim 9,
Wherein the cell edge user identification unit comprises:
When the reception sensitivity has a value lower than a preset threshold value,
Base station. 10. The method of claim 9,
And receiving the information including the reception sensitivity periodically. 16. The method of claim 15,
Wherein the cell edge user identification unit comprises:
When the average value of the predetermined number of times has a value lower than a preset threshold value,
Base station. In a terminal interworking with a base station,
A reception sensitivity calculation unit for calculating reception sensitivity for a second transmission power lower than a first transmission power which is a maximum transmission power of the base station;
A wireless communication unit for transmitting information including the reception sensitivity;
A cell edge user recognition unit for recognizing whether the terminal is located at a cell edge using the reception sensitivity;
A modulation scheme switching unit that changes a first modulation scheme to a second modulation scheme that is strong against noise and interference when the MS is recognized as a terminal located at the edge of the cell;
. 18. The method of claim 17,
The reception sensitivity may be expressed as:
(RSRP), a received signal strength indicator (RSSI), and a channel quality indicator (CQI). 18. The method of claim 17,
Wherein the first modulation scheme has a larger number of symbols to be transmitted per unit time than the second modulation scheme. 18. The method of claim 17,
The first modulation scheme may be one of 16QAM (Quadrature Amplitude Modulation), 64QAM, and 256QAM, and the second modulation scheme is Quadrature Phase Shift Keying (QPSK).

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