WO2016076644A1 - Method and apparatus for transmitting positioning reference signal - Google Patents

Abstract

The present invention relates to a technology for estimating a position of a terminal using a positioning reference signal. More specifically, the present invention relates to a method and apparatus for controlling a transmission period or transmission power of a positioning reference signal in order to accurately measure a position of a terminal. In particular, the present invention provides a method and apparatus for estimating a position of a terminal, the method comprising the steps of: receiving a positioning reference signal from each of a serving cell and one or more neighboring cells; generating reference signal time difference (RSTD) information on the basis of information on a reception time of the positioning reference signal; and estimating a position of a terminal on the basis of the RSTD information.

Description

Location reference signal transmission method and device

The present invention relates to a technique for estimating the position of a terminal using a positioning reference signal. More specifically, the present invention relates to a method and apparatus for controlling a transmission period or transmission power of a location reference signal in order to accurately measure the position of the terminal.

As communication systems evolve, consumers, such as businesses and individuals, are demanding wireless terminals that support a variety of services.

In current mobile communication systems such as 3GPP, Long Term Evolution (LTE), and LTE-A (LTE Advanced), it is a high-speed, high-capacity communication system that can transmit and receive various data such as video and wireless data, beyond voice-oriented services. In addition, there is a need to develop a technology capable of transmitting large amounts of data comparable to a wired communication network, as well as an appropriate error detection method that can improve system performance by minimizing reduction of information loss and improving system transmission efficiency. Doing.

In addition, in various current communication systems, various reference signals have been proposed to provide information on a communication environment to the counterpart device through uplink or downlink.

Among them, in order to measure the position of a user equipment (UE), each cell or base station transmits a Positioning Reference Signal (PRS) to the terminal, and the corresponding terminal transmits each of these signals at a specific time. The position reference signal from the base station is received and the position is measured.

However, the conventional position measurement of the terminal using the position reference signal has a problem in that accurate position measurement is difficult when the terminal is located indoors or in a situation where it is difficult to receive the position reference signal.

The present invention devised in the above-described background is to propose a method and apparatus for setting a transmission parameter so that the terminal can measure the exact position using the location reference signal.

In addition, the present invention is to propose a method and apparatus for adjusting the position reference signal to enable accurate position measurement even when the terminal is located indoors.

According to an aspect of the present invention, a method for estimating a location of a terminal includes receiving a location reference signal from a serving cell and each of one or more neighboring cells and based on the reception time information of the location reference signal. A method includes generating reference signal time difference (RSTD) information and estimating a position of a terminal based on reference signal time difference information.

In addition, the present invention provides a terminal for estimating a position, wherein a reference unit receives a reference signal time difference based on a reception unit for receiving a position reference signal from each of a serving cell and one or more neighboring cells and reception time information of the position reference signal. RSTD) information, and a control unit for estimating the position of the terminal based on the reference signal time difference information.

According to the present invention, there is an effect of providing a method and apparatus for setting a transmission parameter so that the terminal can measure the exact position using the location reference signal.

In addition, the present invention provides an effect that enables accurate position measurement even when the terminal is located indoors.

1 is a view for explaining a position estimation method of a terminal according to the OTDOA method.

2 is a flowchart illustrating a position estimation operation of a terminal according to an embodiment of the present invention.

3 is a diagram illustrating a resource element allocation pattern of a location reference signal.

4 is a view for explaining a method of transmitting a location reference signal according to an embodiment of the present invention.

5 is a diagram for describing transmission power allocation of a location reference signal according to an embodiment of the present invention.

6 is a diagram for explaining a structure of an uplink subframe used in a UTDOA scheme.

7 is a diagram for describing an example of a subframe in which a sounding reference signal is transmitted.

8 is a view for explaining the configuration of a terminal according to an embodiment of the present invention.

Hereinafter, some embodiments of the present invention will be described in detail through exemplary drawings. In adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are assigned to the same components as much as possible even though they are shown in different drawings. In addition, in describing the present invention, when it is determined that the detailed description of the related well-known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

In the present specification, the MTC terminal may mean a terminal supporting low cost (or low complexity) or a terminal supporting coverage enhancement. In the present specification, the MTC terminal may mean a terminal supporting low cost (or low complexity) and coverage enhancement. Alternatively, in the present specification, the MTC terminal may mean a terminal defined in a specific category for supporting low cost (or low complexity) and / or coverage enhancement.

In other words, in the present specification, the MTC terminal may mean a newly defined 3GPP Release-13 low cost (or low complexity) UE category / type for performing LTE-based MTC related operations. Alternatively, in the present specification, the MTC terminal supports enhanced coverage compared to the existing LTE coverage, or supports UE category / type defined in the existing 3GPP Release-12 or lower, or newly defined Release-13 low cost (or lower power consumption). low complexity) can mean UE category / type.

The wireless communication system in the present invention is widely deployed to provide various communication services such as voice, packet data, and the like. The wireless communication system includes a user equipment (UE) and a base station (base station, BS, or eNB). In the present specification, a user terminal is a generic concept meaning a terminal in wireless communication. In addition, user equipment (UE) in WCDMA, LTE, and HSPA, as well as mobile station (MS) in GSM, user terminal (UT), and SS It should be interpreted as a concept that includes a subscriber station, a wireless device, and the like.

A base station or a cell generally refers to a station that communicates with a user terminal, and includes a Node-B, an evolved Node-B, an Sector, a Site, and a BTS. Other terms such as a base transceiver system, an access point, a relay node, a remote radio head (RRH), a radio unit (RU), and a small cell may be called.

That is, in the present specification, a base station or a cell is interpreted in a comprehensive sense to indicate some areas or functions covered by a base station controller (BSC) in CDMA, a NodeB in WCDMA, an eNB or a sector (site) in LTE, and the like. It is meant to cover various coverage areas such as mega cell, macro cell, micro cell, pico cell, femto cell and relay node, RRH, RU, small cell communication range.

Since the various cells listed above have a base station for controlling each cell, the base station may be interpreted in two senses. i) A device providing a mega cell, a macro cell, a micro cell, a pico cell, a femto cell, a small cell in relation to a radio area, or ii) may indicate the radio area itself. In i) all devices which provide a given wireless area are controlled by the same entity or interact with each other to cooperatively configure the wireless area to direct the base station. The eNB, RRH, antenna, RU, LPN, point, transmit / receive point, transmit point, receive point, and the like, according to the configuration of the radio region, become an embodiment of the base station. In ii), the base station may indicate the radio area itself to receive or transmit a signal from a viewpoint of a user terminal or a neighboring base station.

Therefore, mega cells, macro cells, micro cells, pico cells, femto cells, small cells, RRHs, antennas, RUs, low power nodes (LPNs), points, eNBs, transmission / reception points, transmission points, and reception points are collectively referred to the base station. Refers to.

In the present specification, the user terminal and the base station are two transmitting and receiving entities used to implement the technology or technical idea described in this specification in a comprehensive sense and are not limited by the terms or words specifically referred to. The user terminal and the base station are two types of uplink or downlink transmitting / receiving subjects used to implement the technology or the technical idea described in the present invention, and are used in a generic sense and are not limited by the terms or words specifically referred to. Here, the uplink (Uplink, UL, or uplink) refers to a method for transmitting and receiving data to the base station by the user terminal, the downlink (Downlink, DL, or downlink) means to transmit and receive data to the user terminal by the base station It means the way.

There is no limitation on the multiple access scheme applied to the wireless communication system. Various multiple access techniques 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-TDMA, OFDM-CDMA Can be used. One embodiment of the present invention can be applied to resource allocation in the fields of asynchronous wireless communication evolving to LTE and LTE-advanced through GSM, WCDMA, HSPA, and synchronous wireless communication evolving to CDMA, CDMA-2000 and UMB. The present invention should not be construed as being limited or limited to a specific wireless communication field, but should be construed as including all technical fields to which the spirit of the present invention can be applied.

The uplink transmission and the downlink transmission may use a time division duplex (TDD) scheme that is transmitted using different times, or may use a frequency division duplex (FDD) scheme that is transmitted using different frequencies.

In addition, in a system such as LTE and LTE-A, a standard is configured by configuring uplink and downlink based on one carrier or a pair of carriers. The uplink and the downlink include a Physical Downlink Control CHannel (PDCCH), a Physical Control Format Indicator CHannel (PCFICH), a Physical Hybrid ARQ Indicator CHannel (PHICH), a Physical Uplink Control CHannel (PUCCH), an Enhanced Physical Downlink Control CHannel (EPDCCH), and the like. Control information is transmitted through the same control channel, and data is configured by a data channel such as a physical downlink shared channel (PDSCH) and a physical uplink shared channel (PUSCH).

On the other hand, control information may also be transmitted using an enhanced PDCCH (EPDCCH or extended PDCCH).

In the present specification, a cell means a component carrier having a coverage of a signal transmitted from a transmission / reception point or a signal transmitted from a transmission point or a transmission / reception point, and the transmission / reception point itself. Can be.

A wireless communication system to which embodiments are applied may be a coordinated multi-point transmission / reception system (CoMP system) or a coordinated multi-antenna transmission scheme in which two or more transmission / reception points cooperate to transmit a signal. antenna transmission system), a cooperative multi-cell communication system. The CoMP system may include at least two multiple transmission / reception points and terminals.

The multiple transmit / receive point is at least one having a high transmission power or a low transmission power in a macro cell region, which is connected to an eNB or a macro cell (hereinafter referred to as an 'eNB') and wired controlled by an optical cable or an optical fiber to an eNB. May be RRH.

Hereinafter, downlink refers to a communication or communication path from a multiple transmission / reception point to a terminal, and uplink means a communication or communication path from a terminal to multiple transmission / reception points. In downlink, a transmitter may be part of multiple transmission / reception points, and a receiver may be part of a terminal. In uplink, a transmitter may be part of a terminal, and a receiver may be part of multiple transmission / reception points.

Hereinafter, a situation in which a signal is transmitted and received through a channel such as a PUCCH, a PUSCH, a PDCCH, an EPDCCH, and a PDSCH may be expressed in the form of 'sending and receiving a PUCCH, a PUSCH, a PDCCH, an EPDCCH, and a PDSCH.'

In addition, hereinafter, a description of transmitting or receiving a PDCCH or transmitting or receiving a signal through the PDCCH may be used as a meaning including transmitting or receiving an EPDCCH or transmitting or receiving a signal through the EPDCCH.

That is, the physical downlink control channel described below may mean PDCCH or EPDCCH, and may also be used to include both PDCCH and EPDCCH.

In addition, for convenience of description, the EPDCCH, which is an embodiment of the present invention, may be applied to the portion described as the PDCCH, and the EPDCCH may be applied to the portion described as the EPDCCH as an embodiment of the present invention.

Meanwhile, high layer signaling described below includes RRC signaling for transmitting RRC information including an RRC parameter.

The eNB performs downlink transmission to the terminals. The eNB includes downlink control information and an uplink data channel (eg, a physical downlink shared channel (PDSCH), which is a primary physical channel for unicast transmission, and scheduling required to receive the PDSCH. For example, a physical downlink control channel (PDCCH) for transmitting scheduling grant information for transmission on a physical uplink shared channel (PUSCH) may be transmitted. Hereinafter, the transmission and reception of signals through each channel will be described in the form of transmission and reception of the corresponding channel.

Location estimation method of terminal

Recently, the location estimation method of the terminal has increased due to various applications in real life. The well-known methods of the location estimation method of the terminal can be largely classified into a GPS (Global Positioning System) based method and a terrestrial positioning based method.

GPS-based method is a method for measuring the location of the user device using a satellite, there is a disadvantage that requires a signal transmitted from at least four satellites, and cannot be used in an indoor environment. On the other hand, the terrestrial location-based method is a method of measuring the location of the terminal using a timing difference (timing difference) of the signal transmitted from the base stations, a signal transmitted from at least three base stations is required. The ground positioning based method has a poor position estimation performance compared to the GPS based method, but has an advantage that it can be used in almost all environments. The terrestrial positioning based method mainly estimates the position of a terminal using a synchronization signal or a reference signal. In addition, the ground positioning based method may be defined in various terms. For example, it is defined as Observed Time Difference Of Arrival (OTDOA) in UMTS Terrestrial Radio Access Network (UTRAN), Enhanced Observed Time Difference (E-OTD) in GSM / EDGE Radio Access Network (GERAN), and in CDMA2000. Defined as AFLT (Advanced Forward Link Trilateration). In this specification, these various terms are described in a terrestrial positioning-based manner in a comprehensive sense, and there is no limitation on the terms.

1 is a view for explaining a position estimation method of a terminal according to the OTDOA method.

As shown in FIG. 1, since the terminal 100 performs a reference clock based on a subframe transmitted from a current serving cell 110, neighboring cells 120 and 130. The signals received from) have different TDOAs.

For example, a method of determining a location of the terminal 100 using OTDOA will be described. When the reference cell is the serving cell 110 or the terminal 100 performs an operation such as a handover, the reference cell may be a serving cell before the handover operation and may not be changed regardless of the handover operation of the terminal 100. The location estimation method of the UE may be performed through a common reference signal (CRS) or a synchronization signal (Primary Synchronization Signal / Secondary Synchronization Signal, PSS / SSS), but a dedicated location reference signal for a LoCation Service (LCS). (Positioning Reference Signal, hereinafter referred to as "PRS") may be defined and used. The terminal 100 receives a plurality of times and a plurality of times to receive a signal from one serving cell 110 using a location reference signal or a synchronization signal received from one reference cell 110 and a plurality of neighboring cells 120 and 130. The position may be estimated by obtaining a difference in time taken to receive a signal from each of the neighboring cells 120 and 130. For example, the terminal of the present invention may transmit information on the difference in signal reception time to an serving-serving mobile location center (E-SMLC). The E-SMLC may calculate the position of the terminal 100 by solving a linearlized equation using Taylor series expansion using information on the received time difference. Information about the location of the terminal 100 may be transmitted to the terminal 100. Alternatively, the terminal 100 of the present invention may estimate the position in the terminal itself without additional information transmission to the E-SMLC by using the time difference of the received signal.

2 is a flowchart illustrating a position estimation operation of a terminal according to an embodiment of the present invention.

The terminal according to an embodiment of the present invention receives the reference signal from each of the serving cell and one or more neighboring cells and the reference signal time difference (RSTD) information based on the reception time information of the location reference signal And generating a location of the terminal based on the reference signal time difference information.

Referring to FIG. 2, the terminal of the present invention includes receiving a location reference signal from each of a serving cell and one or more neighboring cells (S210). The terminal receives a location reference signal for position estimation from the serving cell. In addition, the terminal receives a location reference signal from each of one or more neighboring cells. In this case, the location reference signal may be received based on preset location reference signal configuration information.

For example, the terminal may receive information on the location reference signal configuration index from the serving cell. The location reference signal configuration index includes index information corresponding to preset location reference signal configuration information. The terminal may identify the location reference signal configuration information corresponding to the received location reference signal configuration index and receive the location reference signal according to the location reference signal configuration information.

The position reference signal configuration information includes information on the transmission period of the position reference signal required for the terminal to receive the position reference signal, subframe offset information on which the position reference signal is transmitted, and information on transmission subframes on which the position reference signal is transmitted. It may include at least one information. Each information included in the position reference signal configuration information will be described in more detail below.

In addition, the terminal of the present invention includes generating reference signal time difference (RSTD) information based on the reception time information of the location reference signal (S220). The terminal checks the information on the reception time of the location reference signal received from the serving cell and each neighbor cell, and calculates information on the difference in the reception time of each location reference signal. Information on the difference in reception time of each location reference signal will be described as RSTD information. For example, the difference between the reception time of the location reference signal transmitted by the serving cell 110 and the reception time of the location reference signal transmitted by the neighbor cell 2 130 is calculated as TDOA2 in FIG. 1. Similarly, the difference between the reception time of the location reference signal transmitted by the serving cell 110 and the reception time of the location reference signal transmitted by the neighbor cell 1 120 in FIG. 1 may be calculated as TDOA1. As described above, the terminal generates RSTD information based on the information on the reception time difference of the location reference signal transmitted by neighboring cells based on the reference cell (eg, the serving cell).

In addition, the terminal of the present invention includes the step of estimating the position of the terminal based on the reference signal time difference information (S230). The terminal may estimate the position of the terminal based on the above-described RSTD information. There is no limitation on a specific method of estimating the position of the terminal based on the RSTD information. For example, triangulation may be performed using location information and RSTD information of each cell transmitting the location reference signal. Alternatively, the position may be estimated using the linear equation in the aforementioned OTDOA.

As described above, the terminal may estimate the position of the terminal by receiving the location reference signal.

Meanwhile, the terminal may estimate the location of the terminal by using the RSTD, or transmit the RSTD information to the location server as described above, and the location server may estimate the location of the terminal. To this end, the terminal may transmit the RSTD information to the serving cell. Thereafter, the terminal may receive information on the location of the terminal estimated by the location server of the serving cell from the serving cell.

In the present invention, the terminal may be located where the location reference signal does not reach smoothly, such as in a building. To this end, the present invention describes a method for changing the various information of the location reference signal configuration information to enable the terminal to receive the location reference signal.

First, the positioning reference signal (hereinafter referred to as "PRS") will be described in more detail.

The PRS is a reference signal used for positioning of the terminal and is transmitted only through resource blocks of a downlink subframe determined for PRS transmission.

The PRS sequence may be defined as in Equation 1.

[Equation 1]

는 PRS 시퀀스를 나타내고, n_s는 무선프레임 내에서 슬롯 번호를 나타내고, l은 슬롯 내에서 OFDM 심볼 번호를 나타낸다. c(i)는 슈도 랜덤(pseudo-random) 시퀀스를 나타내고, 슈도 랜덤 시퀀스 생성기는 OFDM 심볼 각각의 시작점에서 수학식 2와 같은 c_init로 초기화된다. 또한,

는 서브캐리어의 개수로 표현될 수 있는 최대 하향링크 밴드폭을 의미한다. here,

Denotes a PRS sequence, n _s denotes a slot number in a radio frame, and l denotes an OFDM symbol number in a slot. c (i) represents a pseudo-random sequence, and the pseudo random sequence generator is initialized with c _init as shown in Equation 2 at the start of each OFDM symbol. Also,

Denotes a maximum downlink bandwidth that can be expressed by the number of subcarriers.

[Equation 2]

는 물리계층 셀 아이디이고,

는 OFDM 심볼이 일반 순환전치(cyclic prefix, CP)를 가질 때는 1이고 확장된 CP를 가질 때는 0이다.here,

Is the physical layer cell ID,

Is 1 when the OFDM symbol has a general cyclic prefix (CP) and 0 when it has an extended CP.

The sequence of the location reference signal may be determined through the above equations (1) and (2).

3 is a diagram illustrating a resource element allocation pattern of a location reference signal. 3 illustrates a resource element in which a location reference signal transmitted through antenna port 6 is allocated in one subframe in the case of a normal CP. As shown in FIG. 3, the location reference signal may be transmitted by hopping in units of frequencies.

On the other hand, the location reference signal of the present invention is to change the configuration information of the location reference signal dynamically so that the terminal smoothly receives the location reference signal even if the location of the terminal is not suitable for signal reception, such as in the building or underground Can be.

To this end, the terminal of the present invention may receive location reference signal index information from the serving cell and receive the location reference signal using the location reference signal configuration information corresponding to the corresponding index. Table 1 shows an example of configuration information of the location reference signal corresponding to the location reference signal index information.

Referring to Table 1, a PRS transmission period and subframe offset information correspond to each location reference signal index (IPRS).

Additionally, in the present invention, the cell transmitting the location reference signal may dynamically change the location reference signal transmission period, transmission subframe or transmission power in order to improve the location reference signal reception rate of the terminal.

First, the transmission period of the position reference signal will be described.

4 is a view for explaining a method of transmitting a location reference signal according to an embodiment of the present invention.

Referring to FIG. 4, the location reference signal may be transmitted in some radio frames at a set transmission period. In detail, when the transmission period is 40 ms, the location reference signal may be transmitted in units of 4 radio frames.

For example, in the present invention, the position reference signal is received at a transmission period set to 40 ms times N, and N may be configured to 32 of 1, 4, 8, and 16. For example, a 40 ms transmission period may be additionally included in the transmission period shown in Table 1. In addition, a location reference signal index corresponding to a 40 ms transmission period may be set. Alternatively, the location reference signal transmission period is set to an integer multiple of 40 ms, and each cell may transmit the location reference signal at a transmission period set to an integer multiple of 40 ms.

As another example, the cell may transmit the location reference signal in the first transmission period, and intermittently transmit the location reference signal for the terminal located in the building in the second transmission period. For example, the cell transmits the location reference signal at a 160 ms transmission period, but in the case of the nth transmission location reference signal, the cell may set a shorter transmission period. That is, while transmitting the location reference signal in a first transmission period of 160ms, the location reference signal m may be additionally transmitted in a second transmission period set in advance between the fourth and fifth location reference signal transmissions. Through this, the terminal can more smoothly receive the location reference signal.

Meanwhile, the location reference signal may be repeatedly transmitted through a plurality of subframes within one radio frame.

As an example, the location reference signal may be repeatedly transmitted in consecutive K subframes. In FIG. 4, the case where K is 4 is exemplarily illustrated. That is, the position reference signal may be determined based on the subframe offset information, and the position of the subframe in which the transmission starts is transmitted, and may be continuously transmitted through the K subframes from the corresponding position. Referring to FIG. 4, the location reference signal may be transmitted in subframes 3, 4, 5, and 6.

As another example, the location reference signal may be set to have a different number of subframes continuously transmitted for each radio frame. This increases the number of repetitive transmissions of the location reference signal while saving waste of radio resources so that the terminal can receive the location reference signal more smoothly. For example, the position reference signal set to a transmission period of 40 ms may be repeatedly transmitted through two subframes in the first transmission radio frame and repeatedly transmitted through four subframes in the second transmission radio frame.

On the other hand, the position reference signal of the present invention may be dynamically set the transmission power.

5 is a diagram for describing transmission power allocation of a location reference signal according to an embodiment of the present invention.

For example, each cell may set the transmission power of the location reference signal relatively higher than other reference signals (for example, CRS, DM-RS, etc.). Specifically, the transmission power of the location reference signal may be set high at a specific period. For example, the transmission power of the location reference signal may be set up by a predetermined value every four radio frames.

As another example, the location reference signal may be set such that the transmission power in the L th subframe among the K consecutive subframes in one radio frame is allocated higher than the L-1 th transmission power. In this case, L is a natural number from 2 to K. 5, K is 4 and L is 2, 3, 4. Therefore, the transmission power of the location reference signal transmitted in subframe 520 may be set higher than the transmission power of the location reference signal transmitted in subframe 510. Similarly, the transmission power of the location reference signal transmitted in subframe 530 may be set higher than the transmission power of the location reference signal transmitted in subframe 520. In addition, the transmission power of the location reference signal transmitted in subframe 540 may be set higher than the transmission power of the location reference signal transmitted in subframe 530. In this case, the transmission power of the location reference signal transmitted in subframe 510 may be the same as the transmission power of the location reference signal transmitted in subframe 560. Similarly, 520 may be equal to 570, 530 may be equal to 580, and 540 may be equal to 590.

As another example, the transmission power of the location reference signal in units of radio frames may be increased, and at the same time, the location reference signal transmission power in one radio frame may also be increased. That is, the transmission power of the radio frame may be increased at regular intervals, and even in this case, the transmission power of each subframe within the same radio frame may be increased.

As another example, the transmission power may be increased and transmitted only in a specific transmission period.

As described above, in the position reference signal of the present invention, at least one of a transmission period, a number of transmission subframes, and a transmission power may be dynamically set. In addition, the embodiments may be performed in combination with each other.

Meanwhile, the terminal of the present invention may receive a parameter for estimating the 3D position in estimating the position. For example, when a large number of small cells or radio units (RUs) are deployed in a building, the terminal may use information about the location of the small cell or RU as a parameter in order to check information on which floor the terminal is located. Can be delivered to. Through this, the UE additionally receives the position reference signal received from the small cell or RU, the position reference signal received from the serving cell, and information on the position of each small cell or RU, the serving cell as parameters, and estimates the 3D position of the terminal. You may.

In the above, the method for estimating location through dynamic setting of the location reference signal when the signal reception environment of the terminal according to the embodiment of the present invention is bad has been described.

There is also a method for the base station to measure the position based on the reference signal transmitted by the terminal. This is called UTDOA. The present invention has the technical idea of dynamically setting configuration information of a reference signal, which is a reference for position estimation, in order to increase the accuracy of position estimation. Therefore, each embodiment of the present invention may be applied to UTDOA. However, in this case, the sounding reference signal SRS may be used as the position reference signal, and the transmitting entity of the position reference signal is a terminal and the receiving entity is a base station.

Hereinafter, a case of using the UTDOA method will be described with reference to the drawings.

Another example of the above-described ground position estimation method is the UTDOA method using uplink time delay of arrival (UTDOA) measurement. Specifically, the location of the terminal may be determined using uplink arrival time delay measurements for a reference signal (eg, sounding reference signal) transmitted from the terminal to its serving cell and two or more neighboring cells. Since the neighbor cells have not been selected as the serving cell, the terminal is very likely to be located near the edge of the neighbor cells or even outside the cell boundaries. Therefore, the strength of the reference signal transmitted from the terminal and received in the neighboring cell is relatively weak compared to the signal strength transmitted from the second terminal operating in the neighboring cell and / or received by the neighboring cell and received in the neighboring cell.

Therefore, hereinafter, a method and apparatus for more efficiently transmitting and receiving a location reference signal for position estimation of a terminal using the UTDOA scheme are proposed. Hereinafter, a sounding reference signal will be described as an example of a location reference signal transmitted by a terminal, but is not limited thereto.

6 is a diagram for explaining a structure of an uplink subframe used in a UTDOA scheme.

Referring to FIG. 6, the uplink subframe includes a control region 610 to which a physical uplink control channel (PUCCH) carrying an uplink control signal is allocated and a physical region to which a physical uplink shared channel (PUSCH) carrying user data is allocated. 620). In order to maintain a single carrier characteristic in SC-FDMA, one resource terminal is allocated with consecutive resource blocks in the frequency domain.

PUCCH for one UE is allocated to an RB pair in a subframe. Resource blocks belonging to a resource block pair occupy different subcarriers in each of a first slot and a second slot. The resource block pair allocated to the PUCCH is said to be frequency hopping at a slot boundary. m is a location index indicating a frequency domain location of a resource block allocated to a PUCCH in a subframe.

The PUSCH is mapped to an UL-SCH (Uplink Shared Channel) which is a transport channel. The uplink control signal transmitted on the PUCCH includes a HARQ (Hybrid Automatic Repeat and reQuest) ACK / NACK (Acknowledgement. (Scheduling Request). PUCCH may support multiple formats. That is, an uplink control signal having a different number of bits per subframe may be transmitted according to a modulation scheme. For example, when using BPSK (Binary Phase Shift Keying), 1-bit uplink control information can be transmitted on PUCCH, and when using QPSK (Quadrature Phase Shift Keying), 2-bit uplink control information is PUCCH. Can be sent over the air.

Sounding reference signal

Hereinafter, a method of transmitting a sounding reference signal (SRS) will be described. The sounding reference signal is a reference signal transmitted by the terminal to the base station for uplink scheduling. The base station estimates an uplink channel based on the received sounding reference signal and uses the estimated uplink channel for uplink scheduling.

7 is a diagram for describing an example of a subframe in which a sounding reference signal is transmitted. Referring to FIG. 7, a sounding reference signal is transmitted through one SC-FDMA symbol 700 in a subframe. Hereinafter, the SC-FDMA symbol 700 in the period in which the sounding reference signal is transmitted will be referred to as a sounding symbol. Here, the last SC-FDMA symbol 700 of the 14 SC-FDMA symbols constituting the subframe is a sounding symbol, but this is only an example, and the position or number of sounding symbols in the subframe may be variously changed.

The sounding reference signal is not transmitted in the control area but in the data area. The terminal may transmit the sounding reference signal over the entire frequency (or subcarrier) of the data region or over some frequency of the data region.

When the terminal transmits a sounding reference signal over some frequencies, the terminal may hop and transmit a different frequency for each subframe in which the sounding reference signal is transmitted. In addition, the terminal may transmit the sounding reference signal using only subcarriers with even or odd indexes. The terminal may transmit the sounding reference signal periodically or aperiodically.

The sounding reference signal may be transmitted in a form in which a specific cyclic shift value is applied to the basic sequence. The basic sequence may be a PN sequence, a ZC sequence, or a computer generated CAZAC sequence.

In the UTDOA type estimation method, the position can be estimated using the SRS.

However, when buildings are densely populated, such as in an urban environment, or when a user is located in a building, the SRS transmitted by the terminal may not be properly transmitted to the base station. In addition, in the case of a non-serving cell in which the terminal does not currently communicate, interference may occur due to the SRS signal of the terminal. Therefore, in this case, a problem that it is difficult to accurately measure the terminal position may occur. In particular, when a terminal is located in a building, there is a difficulty in estimating a location using a satellite such as GNSS. Therefore, a method for estimating an accurate location of a user terminal located in a building is required.

The main parameters of the conventional SRS are shown in Tables 2 to 5. Table 2 6≤N ^UL _RB, and _{m SRS, b, N b (} b = 0, 1, 2, 3) at ≤40, Table 3 40≤N ^UL _RB at ≤60 m _{SRS, b,} N _b (b = 0, 1, 2, 3), Table 4 is m _{SRS, b} , N _b (b = 0, 1, 2, 3) at 60 ≦ N ^UL _RB ≦ 80, and Table 5 is 80 M _{SRS, b} , N _b (b = 0, 1, 2, 3) at? N ^UL _RB ?

However, as described above, in estimating the position of the terminal using the conventional SRS, when the terminal is located in the building, a problem may occur in that the SRS reach is reduced by the wall of the building or various objects.

Therefore, in order to solve this problem, it is necessary to newly design the conventional SRS.

A terminal according to an embodiment of the present invention may dynamically set main parameters of an SRS, similarly to a method of dynamically setting a PRS and estimating a location.

The terminal may dynamically adjust the transmission period of the SRS.

For example, the SRS may be transmitted to the base station more frequently by setting to reduce the transmission period of the SRS. For example, the SRS transmission period may be set to an integer multiple of 5ms, and the terminal may transmit the SRS signal at a transmission period set to an integer multiple of 5ms.

As another example, the terminal may transmit the SRS in the existing transmission period, and the terminal located in the building may intermittently transmit the SRS at an additional predetermined period. That is, while transmitting the SRS in the existing existence period, the transmission period can be set short in the case of the n-th transmitted SRS. For example, SRS may be additionally transmitted in a preset transmission period between the fourth and fifth SRS transmissions.

The terminal may transmit by widening the transmission band width of the SRS. For example, the transmission band width of the SRS may be dynamically changed within a range not exceeding the uplink transmission band width.

Alternatively, the terminal may set the transmission power for SRS transmission to be higher than other reference signals.

For example, the SRS transmission power may be ramped up and transmitted by a predetermined number of times according to a transmission period. That is, in the case of setting 5 times, the SRS transmission power may be allocated by increasing the second transmission power by a predetermined value than the first transmission power. Similarly, the third transmit power may be set higher than the second transmit power.

As another example, the transmission power may be changed in the case of a specific transmission period according to the SRS transmission period. Alternatively, a new SRS transmission period may be added and the SRS transmission power may be changed and transmitted only when the SRS is transmitted in the added SRS transmission period.

The terminal may repeatedly transmit the SRS.

For example, the UE may repeatedly transmit the SRS a predetermined number of times and set a repetition level. That is, when the base station does not receive the SRS, the SRS may be repeatedly transmitted k times according to the next repetition level.

As another example, the UE may perform SRS transmission by mixing the above-described repetition level and the change of the transmission power. For example, if the terminal transmits the SRS while increasing the repetition level, but if the base station does not receive the maximum repetition level, the terminal may ramp up the transmission power to transmit the SRS. In this case, the repetition level may be changed to the initial repetition level, and the maximum repetition level may be maintained. The number of repetitions of the SRS may be repeatedly set within a specific radio frame, or may be repeated over a plurality of radio frames.

In the meantime, the UE may modify and set the pattern in allocating the resources of the SRS. For example, the pattern may be added to increase the RE for the SRS in the time-frequency resource, or may be configured by mapping the SRS resource to the reserve RE.

In addition, each embodiment of the above-described SRS transmission method setting may be configured in combination with each other.

A brief description will be given of a terminal configuration capable of performing all of the method for estimating a location of a terminal described above.

8 is a view for explaining the configuration of a terminal according to an embodiment of the present invention.

Referring to FIG. 8, the user terminal 800 according to an embodiment of the present invention may be based on a reception unit 830 for receiving a location reference signal from each of a serving cell and one or more neighboring cells and reception time information of the location reference signal. And a control unit 810 for generating reference signal time difference (RSTD) information and estimating the position of the terminal based on the reference signal time difference information.

In addition, the terminal 800 may further include a transmitter 820 for transmitting the reference signal time difference information to the serving cell. The receiver 830 may receive the location information of the terminal estimated by the location server of the serving cell based on the reference signal time difference information.

In addition, the receiving unit 830 may further receive the location reference signal configuration index and receive the location reference signal from each of the serving cell and one or more neighboring cells based on the location reference signal configuration information. The controller 810 may check preset location reference signal configuration information corresponding to the location reference signal configuration index.

In addition, the receiver 830 receives downlink control information, data, and messages from the base station through a corresponding channel, and the transmitter 820 transmits uplink control information, data, and messages to the base station through the corresponding channel. In addition, the transmitter 820 may transmit the aforementioned uplink reference signal to the base station.

The control unit 810 controls the overall operation of the terminal 800 according to the estimation of the position of the terminal 800 by transmitting and receiving the position reference signal necessary to carry out the present invention.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and changes without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

CROSS-REFERENCE TO RELATED APPLICATION

This patent application is filed with Korean Patent Application No. 10-2014-0156924 filed on November 12, 2014, and Korean Patent Application No. 10-2014-0156928 filed on November 12, 2014, and November 2015. Patent Application No. 10-2015-0158862, filed in Korea on 12 December, claims priority under US Patent Act Article 119 (a) (35 USC § 119 (a)), all of which are hereby incorporated by reference. Incorporated into the application. In addition, if this patent application claims priority for the same reason for countries other than the United States, all its contents are incorporated into this patent application by reference.

Claims (10)

In the method for estimating the position of the terminal, Receiving a location reference signal from each of the serving cell and one or more neighboring cells; Generating reference signal time difference (RSTD) information based on the reception time information of the location reference signal; And Estimating the position of the terminal based on the reference signal time difference information. The method of claim 1, Estimating the location of the terminal, Transmitting the reference signal time difference information to the serving cell; And Receiving location information of the terminal estimated by the location server of the serving cell based on the reference signal time difference information. The method of claim 1, Receiving the location reference signal, Receiving a location reference signal configuration index; And Confirming preset location reference signal configuration information corresponding to the location reference signal configuration index; And And receiving a location reference signal from each of the serving cell and one or more neighboring cells based on the location reference signal configuration information. The method of claim 3, wherein The location reference signal configuration information, And at least one of transmission period information, subframe offset information, and transmission subframe information. The method of claim 1, The position reference signal is, Received in a transmission period set to 40 ms times N, wherein N is any one of 32 among 1, 4, 8, and 16. The method of claim 1, The position reference signal is, And repeatedly transmitted in consecutive K subframes. The method of claim 1, The position reference signal is, The transmission power in the L-th subframe among the K consecutive subframes in one radio frame is assigned to be transmitted higher than the L-1 th transmission power, characterized in that L is a natural number from 2 to K How to. In the terminal for estimating the position, A receiver which receives a location reference signal from each of the serving cell and one or more neighboring cells; And And a controller configured to generate reference signal time difference (RSTD) information based on the reception time information of the location reference signal, and estimate the location of the terminal based on the reference signal time difference information. The method of claim 8, Further comprising a transmitter for transmitting the reference signal time difference information to the serving cell, And the receiving unit receives location information of the terminal estimated by the location server of the serving cell based on the reference signal time difference information. The method of claim 8, The receiving unit, Receiving a location reference signal configuration index and receiving a location reference signal from each of the serving cell and one or more neighboring cells based on the location reference signal configuration information; The control unit is characterized in that for confirming the preset position reference signal configuration information corresponding to the position reference signal configuration index.

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