KR20140129913A - Transmitting Power Control Apparatus and Method - Google Patents

Transmitting Power Control Apparatus and Method Download PDF

Info

Publication number
KR20140129913A
KR20140129913A KR1020130048871A KR20130048871A KR20140129913A KR 20140129913 A KR20140129913 A KR 20140129913A KR 1020130048871 A KR1020130048871 A KR 1020130048871A KR 20130048871 A KR20130048871 A KR 20130048871A KR 20140129913 A KR20140129913 A KR 20140129913A
Authority
KR
South Korea
Prior art keywords
transmission power
base station
reference signal
maximum value
propagation attenuation
Prior art date
Application number
KR1020130048871A
Other languages
Korean (ko)
Inventor
문희찬
Original Assignee
인텔렉추얼디스커버리 주식회사
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 인텔렉추얼디스커버리 주식회사 filed Critical 인텔렉추얼디스커버리 주식회사
Priority to KR1020130048871A priority Critical patent/KR20140129913A/en
Publication of KR20140129913A publication Critical patent/KR20140129913A/en

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
    • H04W52/04—TPC
    • H04W52/18—TPC being performed according to specific parameters
    • H04W52/24—TPC being performed according to specific parameters using SIR [Signal to Interference Ratio] or other wireless path parameters
    • H04W52/241—TPC being performed according to specific parameters using SIR [Signal to Interference Ratio] or other wireless path parameters taking into account channel quality metrics, e.g. SIR, SNR, CIR, Eb/lo
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
    • H04W52/04—TPC
    • H04W52/18—TPC being performed according to specific parameters
    • H04W52/24—TPC being performed according to specific parameters using SIR [Signal to Interference Ratio] or other wireless path parameters
    • H04W52/245—TPC being performed according to specific parameters using SIR [Signal to Interference Ratio] or other wireless path parameters taking into account received signal strength

Abstract

The present invention relates to an apparatus and method for controlling transmission power, and an object of the present invention is to provide an apparatus and method for reducing interference at a base station by a signal from a terminal performing D2D communication.

Description

TECHNICAL FIELD [0001] The present invention relates to a transmission power control apparatus,

The present invention relates to an apparatus and method for controlling transmission power.

As the spread of mobile terminals such as smart phones and the demand for various services using such mobile terminals have been developed, inter-terminal communication capable of directly transferring data between terminals without passing through network infrastructures such as base stations and access points is getting more popular.

For example, LTE (Long Term Evolution) or LTE-Advanced network, in order to provide more diversified services to users, to guarantee the reliability of communication between terminals, or to increase communication capacity through more efficient use of bandwidth. There is a demand for a technology for supporting inter-terminal communication (or D2D (Device to Device) communication) using radio resources of various mobile communication networks.

When D2D communication is supported, the communication between the terminal and the terminal and the communication between the terminal and the base station use the same radio resources. In this case, the signal between the terminal and the terminal may interfere with communication between the terminal and the base station. For example, if a terminal transmits with excessive power for D2D communication, the quality of data received by the base station may deteriorate or the operation of the base station may be interrupted.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an apparatus and method for reducing interference at a base station by a signal from a terminal performing D2D communication.

According to an embodiment of the present invention, there is provided an apparatus comprising: a receiver for receiving a reference signal from a base station; A transmitter for transmitting a signal to another terminal; And a controller for controlling the maximum value of the transmission power or the transmission power of the transmission unit based on the amount of propagation attenuation estimated from the reference signal.

Another embodiment of the present invention is a method for receiving a signal from a base station, comprising: receiving a reference signal from a base station; Calculating a maximum value of transmission power or transmission power based on the amount of propagation attenuation estimated from the reference signal; And transmitting a signal to another terminal according to the calculated maximum value of the transmission power or the transmission power.

According to the present invention, a terminal measures a downlink reception signal to measure a propagation attenuation or a channel quality with a base station, and changes the transmission power or the maximum transmission power used for D2D communication based on the measurement, . In addition, when propagation attenuation below a certain level or channel state above a certain level is measured, the D2D communication can be interrupted to prevent the D2D communication from obstructing the existing communication system and to protect the operation of the existing communication system.

FIG. 1 shows an example of a mobile communication system to which an embodiment of the present invention is applied.
2 shows an example of a downlink channel structure used in LTE.
FIG. 3 illustrates a configuration of a terminal according to an embodiment of the present invention.
4 illustrates a configuration of a terminal according to another embodiment of the present invention.
Figure 5 illustrates a method according to an embodiment of the present invention.

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. It should be noted that, in adding reference numerals to the constituent elements of the drawings, the same constituent elements are denoted by the same reference numerals whenever possible, even if they are shown in different drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

In describing the components of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are intended to distinguish the constituent elements from other constituent elements, and the terms do not limit the nature, order or order of the constituent elements. When a component is described as being "connected", "coupled", or "connected" to another component, the component may be directly connected to or connected to the other component, It should be understood that an element may be "connected,""coupled," or "connected."

FIG. 1 is a schematic view of a wireless communication system to which embodiments are applied.

The wireless communication system 100 is widely deployed to provide various communication services such as voice, packet data, and so on.

1, a wireless communication system 100 includes a first user equipment (UE) 120, a second user equipment 122, and a base station 110 (BS).

The term " UE " in this specification is a generic concept of a user terminal in a wireless communication. UE (User Equipment) in Wideband Code Division Multiple Access (WCDMA) and Long Term Evolution (LTE) and High Speed Packet Access (HSPA) Of course, it should be interpreted as a concept including all of MS (Mobile Station), UT (User Terminal), SS (Subscriber Station), and wireless device in Global System for Mobile communications (GSM).

Each of the terminals can perform feedback of channel information described below and provides the device.

A base station 110 or a cell is generally a station that communicates with a terminal and includes a Node-B, an evolved Node-B (eNB), a Base Transceiver System (BTS), an access point Access Point, Relay Node, and the like.

The base station 110 transmits a reference signal to the terminals 120 and 122, receives channel information from the terminals 120 and 122, and transmits data or signals using the channel information.

That is, the base station 110 or the cell in the present specification should be construed as a comprehensive meaning indicating a partial area covered by a BSC (Base Station Controller) in CDMA (Code Division Multiple Access), a Node-B in WCDMA And covers various coverage areas such as megacell, macrocell, microcell, picocell, femtocell, and relay node communication range.

The term " terminal " and " base station 110 " are used herein in the broadest sense as the two transmitting and receiving subjects used to implement the technical or technical idea described in this specification and are not limited by any specific term or word.

There is no limit to the multiple access scheme that is applied to the wireless communication system 100. Various multiple access schemes such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), OFDM-FDMA, OFDM- Can be used.

A TDD (Time Division Duplex) scheme in which uplink and downlink transmissions are transmitted using different time periods, or an FDD (Frequency Division Duplex) scheme in which they are transmitted using different frequencies can be used.

One embodiment is applied to asynchronous wireless communication that evolves into LTE (Long Term Evolution) and LTE-advanced via GSM, WCDMA, and HSPA, and synchronous wireless communication that evolves into CDMA, CDMA-2000, and UMB (Ultra Mobile Broadband) . The present invention should not be construed to be limited or limited to a specific wireless communication field and should be construed as including all technical fields to which the idea of the present invention can be applied.

The wireless communication system 100 to which embodiments are applied may support uplink and / or downlink HARQ (Hybrid ARQ) and may use a channel quality indicator (CQI) for link adaptation. For example, the downlink may be OFDMA (Orthogonal Frequency Division Multiple Access), the uplink may be a Single Carrier-Frequency Division Multiple Access (SC-FDMA) ) Can be used.

2 shows an example of a downlink channel structure used in an LTE system as an example. Figure 2 shows the signal transmitted during a 1 ms subframe. In Fig. 2, the time axis is a symbol unit and the frequency axis is a subcarrier unit. In Fig. 2, a plurality of reference signals are transmitted in addition to the control channel region indicated by "C" and the data channel region indicated by "D ". FIG. 2 shows a case where four antenna ports (R1 to R4) are used for a cell-specific reference signal (CRS). The CRS is used not only for the channel estimation when the UE demodulates the downlink channel, but also for the estimation of the noise level, the downlink quality, and the like.

In the current mobile communication system, the base station 110 transmits data to the terminals 120 and 122 through the downlink, and the terminals 120 and 122 transmit data to the base station 110 through the uplink. However, current mobile communication systems do not provide a way for terminal 120 to transmit data directly to another neighboring terminal 122. [ A communication method in which the terminal 120 transmits data to another adjacent terminal 122 may be referred to as D2D (Device to Device) communication.

As resources available for D2D communication, it is possible to consider uplink resources in which a terminal transmits data to a base station. In the case of the uplink, the subject of reception becomes the base station. The number of base stations in the mobile communication system is small and the terminal can measure information such as propagation attenuation of the channel from the base station to the base station through various methods.

Interference may occur when a terminal transmits data for communication between terminals. Interference can act as an impediment to communication of other users. For example, if a terminal transmits with excessive power for D2D communication, the quality of data received by the base station may deteriorate or the operation of the base station may be interrupted.

In the mobile communication system, each base station can periodically transmit a downlink signal. For example, in W-CDMA or CDMA, the pilot channel may be periodically transmitted. As another example, in LTE or LTE-A, a reference signal may be periodically transmitted. The terminal can measure the quality of the downlink channel based on the pilot or the reference signal. Also, the terminal can measure the downlink channel through various signals of a predetermined format transmitted periodically such as the SYNC channel transmitted in the mobile communication system. In the following embodiments, an example of measuring the quality of a downlink channel using a reference signal (CRS in FIG. 2) in an LTE system will be described. However, the present invention is not limited thereto, and it will be understood by those of ordinary skill in the art that the downlink quality can be measured with a signal of any other fixed format transmitted periodically.

FIG. 3 illustrates a terminal according to an embodiment of the present invention.

3, the terminal 300 includes a receiving unit, a controller 340 and a D2D transmitting unit 360. The receiving unit includes an RF circuit 310, an automatic gain control (AGC) unit 320, an analog- (Digital Converter) 330, and RS RS / I O (Reference Signal Energy / Others Interference).

The RF circuit 310 receives the downlink signal through the antenna.

AGC 320 automatically changes the amplification factor so that the output of the circuit is within a certain level range. The AFC 320 can calculate a Received Signal Strength Indicator (RSSI). The RSSI represents the power of the noise and the total signal received at the receiver.

The signal passed through the AGC 320 is converted into a digital signal by the ADC 330.

The E RS / I O measurer 340 extracts a reference signal from the received signal and calculates a signal-to-noise ratio (SNR) value of the reference signal. Alternatively, the E RS / I O measurer 340 may calculate the value of E RS / I O. Here, the SNR represents the ratio of the power of the signal component received by the terminal to the power of the noise component. E RS represents the energy of the RE (Resource Element) of the reference signal received by the receiver, and I O represents the power spectral density of the power signal received by the receiver. Therefore, E RS / I O can represent the ratio of the power of the received reference signal component measured at the receiver to the power of the total received signal (sum of noise and noise). This value may also be a value proportional to the SNR of the reference signal measured at the receiver.

The controller 350 may determine the channel state of the downlink based on the RSSI value and the E RS / I O value. Further, when the terminal knows the transmission power value of the base station (for example, the base station transmits the base station transmit power value to the terminal), the controller 350 calculates the downlink propagation attenuation Can be estimated.

[Equation 1]

Propagation attenuation 1 = base station transmit power - RSSI + constant 1

&Quot; (2) "

Propagation attenuation 2 = transmit power of the base station - (RSSI + E RS / I O ) + constant 2

The above equations (1) and (2) are expressions expressed in dB scale. Alternatively, the addition may be expressed as a linear scale, and addition may be expressed as multiplication and subtraction may be replaced with division. In the above Equations 1 and 2, the transmission power of the base station may be included in the system information transmitted by the base station in the downlink. In this case, the MS can calculate the propagation loss of Equation (1) or (2) using the value of the transmission power of the BS in the downlink channel transmitted by the BS. Alternatively, in the case of a system in which the base station does not transmit the value of the transmission power in advance, the transmission power of the base station can be preset to a constant value.

Equations (1) and (2) are merely examples, and the channel state of the downlink can be estimated by various other methods, and the propagation loss can be estimated.

The large radio wave attenuation generally means that the distance between the base station and the terminal is large. If the distance between the base station and the terminal is large and the radio wave attenuation is large, even if the terminal performs D2D communication with a relatively large power, the uplink performance may not be significantly affected. Therefore, the terminal can transmit data with a relatively large power for D2D communication. On the other hand, if the radio wave attenuation is small, even if the terminal transmits data with a relatively small power for D2D communication, the uplink performance may be greatly affected.

Therefore, in this specification, the terminal proposes to estimate the channel attenuation using a downlink reference or pilot signal, and to control the transmission power according to the attenuation. That is, the controller 350 can set the power of the signal transmitted through the D2D communication as shown in Equation (3).

&Quot; (3) "

Transmit power of D2D channel = propagation attenuation + constant 3

However, when the amount of data to be transmitted through the D2D communication is small, or when the counterpart terminal is located in a short distance, it is not always necessary to transmit data with the above power. In this case, the controller 350 can set the maximum transmission power that the terminal transmits through D2D communication according to the propagation attenuation as shown in Equation (4).

&Quot; (4) "

Maximum transmission power of D2D channel = min (constant 4, propagation attenuation + constant 5)

In Equation (4), the constant 4 means the maximum power that the terminal can transmit through D2D communication regardless of the attenuation. Constant 5 is a constant used to change the maximum transmission power according to the propagation attenuation.

As described above, the controller 350 controls the transmit power of the D2D channel or the maximum transmit power of the D2D channel, and the D2D transmitter 360 performs the D2D transmission based on the controlled value.

On the other hand, when the terminal is located in the cell boundary region, signals of two or more base stations can be detected. Particularly, in the case of the next generation mobile communication, the probability that a mobile station detects signals of two or more base stations in a cell boundary region can be increased. In this case, it is necessary to prevent the D2D signal transmitted from the terminal from adversely affecting the uplink signals of two or more base stations.

FIG. 4 illustrates a configuration of a terminal when a terminal detects signals of two or more base stations.

4, the terminal 300 'includes a receiving unit, a controller 350, and a D2D transmitting unit 360. The receiving unit includes an RF circuit 310, an AGC 320, an ADC 330, and an E RS / I O meters 340-1 and 340-2.

The RF circuit 310, the AGC 320, and the ADC 330 are similar to those of FIG. 3, and detailed description thereof is omitted.

E RS / IO measuring devices 340-1 and 340-2 can extract a reference signal from each base station in a signal received from two or more base stations and calculate a SNR (Signal-to-Noise Ratio) value. In other words, the first cell E RS / I o measurer 340 - 1 calculates the SNR for the first cell (or first base station), and the second cell E RS / I o measurer 340 - The SNR for the cell (or the second base station) can be calculated. Alternatively, the E RS / I o measurers 340-1 and 340-2 may calculate the value of E RS / I O for each base station. That is, the first cell E RS / I O measurer 340-1 calculates the E RS / I O for the first cell (or the first base station) and the second cell E RS / I O measurer 340-2 May compute E RS / I O for the second cell (or second base station). Here, SNR represents the ratio of the power of the signal component received by the terminal to the power of the noise component, and E RS / I O represents the ratio of the received downlink pilot channel power to the total noise power. Figure 4 illustrates a two RS E / I O Meter (340-1, 340-2) by way of example, but the number of the RS E / I O instrument may be more than two.

The controller 350 can determine the base station with the best downlink channel state and estimate the propagation loss for the base station using Equation (1) or (2). Then, the estimated propagation attenuation can be applied to Equation (3) or (4) to calculate the transmit power of the D2D channel or the maximum transmit power of the D2D channel.

Alternatively, as shown in Equation (5) below, the controller 350 takes the minimum value of the propagation attenuation calculated using Equation 1 or Equation 2 for each base station and sets the minimum value of the propagation attenuation to Equation 3 Or Equation 4 to calculate the transmit power of the D2D channel or the maximum transmit power of the D2D channel.

&Quot; (5) "

Propagation attenuation in the cell boundary region = min (propagation attenuation in the first cell, propagation attenuation in the second cell)

In Equation (5), min (x, y) represents a smaller value of the two values. The transmission power or the maximum transmission power of the D2D channel can be calculated by applying the value of the propagation attenuation in the cell boundary region calculated above to the equation (3) or (4). Although equation (5) is shown as calculating the minimum value for two cells, the present invention is not limited to this, and the minimum value can be calculated for three or more cells.

The D2D transmission unit 360 performs D2D communication based on the transmission power of the D2D channel or the maximum transmission power of the D2D channel calculated by the controller 350. [

5 illustrates a transmission power control method for D2D communication according to an embodiment of the present invention.

Referring to FIG. 5, a terminal receives a downlink pilot signal or a reference signal from one or more base stations (S510).

The terminal calculates the propagation attenuation based on the received pilot signal or the reference signal (S520). The calculation of the propagation attenuation can be calculated using Equation (1) or Equation (2). In Equation (1) or (2), the transmission power of the base station is a state that the terminal knows by signaling or presetting from the base station, and RSSI and / or E RS / I O are calculated by the terminal.

When the terminal receives a downlink pilot signal or a reference signal from two or more base stations, the value of the propagation attenuation is calculated for the base station with the best channel condition, or the value of the propagation attenuation estimated for each base station Can be determined.

The terminal calculates the transmit power of the D2D channel or the maximum transmit power of the D2D channel based on the calculated value of the propagation attenuation (S530). The transmit power of the D2D channel or the maximum transmit power of the D2D channel may be calculated using Equation (3) or Equation (4).

Then, the terminal controls the transmission power for D2D communication based on the calculated transmission power of the D2D channel or the maximum transmission power of the D2D channel (S540).

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

Claims (12)

A receiving unit for receiving a reference signal from a base station;
A transmitter for transmitting a signal to another terminal; And
And a control unit for controlling the maximum value of the transmission power or the transmission power of the transmission unit based on the amount of propagation attenuation estimated from the reference signal. The method according to claim 1,
Wherein the amount of the propagation attenuation is estimated by a magnitude of a received signal or estimated by a magnitude of the received signal and a ratio of a signal to a noise. The method according to claim 1,
Wherein the transmission power of the transmitter controlled by the controller is calculated by adding a first constant to the amount of the propagation attenuation. The method according to claim 1,
Wherein the maximum value of the transmission power of the transmitter controlled by the controller is calculated as a minimum value among a value obtained by adding the second constant to the amount of the propagation attenuation and a third constant. The method according to claim 1,
The receiving unit receives a reference signal from a plurality of base stations,
The control unit determines a base station having the best channel state from the reference signal and determines a maximum value of the transmission power or transmission power of the transmission unit based on the amount of propagation attenuation estimated from the reference signal from the base station having the best channel state And controlling the terminal. The method according to claim 1,
The receiving unit receives a reference signal from a plurality of base stations,
Wherein the control unit estimates the amount of radio wave attenuation for each base station and controls the maximum value of the transmission power or the transmission power of the transmission unit based on the minimum value of the plurality of radio wave attenuation amounts. Receiving a reference signal from a base station;
Calculating a maximum value of transmission power or transmission power based on the amount of propagation attenuation estimated from the reference signal; And
And transmitting a signal to another terminal according to the calculated maximum value of the transmission power or the transmission power. 8. The method of claim 7,
Wherein the amount of the propagation attenuation is estimated by a magnitude of a received signal or estimated by a magnitude of the received signal and a ratio of a signal to a noise. 8. The method of claim 7,
Wherein the transmission power is calculated by adding a first constant to the amount of the propagation attenuation. 8. The method of claim 7,
Wherein the maximum value of the transmission power is calculated as a minimum value among a value obtained by adding the second constant to the amount of the propagation attenuation and a third constant. 8. The method of claim 7,
The reference signal receiving step includes receiving a reference signal from a plurality of base stations,
Wherein the step of calculating the maximum value of the transmission power or the transmission power comprises the steps of: determining a base station having the best channel state from the reference signal; and calculating a maximum value of the transmission power or the transmission power based on the amount of the propagation attenuation estimated from the reference signal from the base station, And calculating a maximum value of the transmission power or the transmission power of the transmission unit on the basis of the maximum transmission power of the transmission unit. 8. The method of claim 7,
The reference signal receiving step includes receiving a reference signal from a plurality of base stations,
Wherein the step of calculating the maximum value of the transmission power or the transmission power includes the steps of estimating the amount of the propagation attenuation for each base station and estimating the maximum value of the transmission power or the transmission power based on the minimum of the amounts of the plurality of propagation attenuation. And controlling a maximum value of the transmission power of the terminal.
KR1020130048871A 2013-04-30 2013-04-30 Transmitting Power Control Apparatus and Method KR20140129913A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
KR1020130048871A KR20140129913A (en) 2013-04-30 2013-04-30 Transmitting Power Control Apparatus and Method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
KR1020130048871A KR20140129913A (en) 2013-04-30 2013-04-30 Transmitting Power Control Apparatus and Method

Publications (1)

Publication Number Publication Date
KR20140129913A true KR20140129913A (en) 2014-11-07

Family

ID=52455076

Family Applications (1)

Application Number Title Priority Date Filing Date
KR1020130048871A KR20140129913A (en) 2013-04-30 2013-04-30 Transmitting Power Control Apparatus and Method

Country Status (1)

Country Link
KR (1) KR20140129913A (en)

Similar Documents

Publication Publication Date Title
US8761826B2 (en) Uplink power control in coordinated multi-point wireless communication system
US9769765B2 (en) System and method for direct mobile communications power control
CN110062408B (en) Method and radio network node for measuring interference
KR101906332B1 (en) Method and apparatus for mitigation of interference due to peer-to-peer communication
JP5814041B2 (en) Radio communication system, radio base station apparatus, user terminal, and radio communication method
JP5712934B2 (en) Relay device, relay system, relay method, wireless communication system, program
EP2247143A1 (en) Relay transmission system, base station, relay station, and method
US9107177B2 (en) Wireless base station, transmission power control method and computer program
CN110149689B (en) Power control method and device
RU2506720C1 (en) Method and apparatus for controlling uplink power
US9979503B2 (en) Signal transmission with interference mitigation
US20130102307A1 (en) Radio base station apparatus, mobile terminal device, and cell selecting method
WO2014114106A1 (en) Uplink data reception method and apparatus for wireless transceiving device
WO2014098737A1 (en) Tracking received power in wireless communications
JP5949402B2 (en) Receiving apparatus and receiving method
JP7128650B2 (en) User terminal and radio base station
KR20140129913A (en) Transmitting Power Control Apparatus and Method
JP2012114861A (en) Base station and communication control method
KR101315193B1 (en) Output power control system and method for a mobile repeater
KR20150021253A (en) System and Method for Measuring Position of Mobile Terminal using Connection Information
KR20150063915A (en) Transmit power control method of terminal in direct communication between terminals, terminal supporting the same

Legal Events

Date Code Title Description
N231 Notification of change of applicant
WITN Withdrawal due to no request for examination