KR100834634B1 - Apparatus and methods for location service in mobile communication system - Google Patents

Abstract

The present invention provides a terminal in a narrow band time division duplexing code division multiple access communication method (NB-TDD) in a third generation mobile communication system using a code division multiple access method. A method and apparatus for estimating position information capable of estimating a position of a?

In the mobile communication system according to the present invention, a method for estimating the position of a terminal may include receiving pilot channel signals from a serving base station and a plurality of neighbor base stations of the terminal during a specific downlink signal period, and receiving from the serving base station. When the power of the received pilot channel signal is greater than a preset threshold, the pilot signal received from the serving base station is removed by removing the pilot signal received from the serving base station from the pilot channel signals received from the serving base station and the plurality of neighbor base stations. Outputting a channel signal and outputting a pilot channel signal received from the serving base station and the plurality of adjacent base stations when the power of the pilot channel signal received from the serving base station is less than a preset threshold, and outputting the output pilot channel Signals After decoding, after calculating a time difference between pilot channel signals having a power greater than a predetermined minimum power among the decoded pilot channel signals, the serving base station and the location estimation information including the time difference between the pilot channel signals are calculated. And transmitting to at least one base station among a plurality of neighboring base stations, and estimating the position of the terminal using the position estimation information at the base station receiving the position measurement information.

NB TDD, Location Service, UE Location Estimation, DwPCH, Signal Eliminator

Description

Apparatus and methods for location service in mobile communication system}

1 is a diagram illustrating the configuration of a radio access network of a narrowband time division duplexing (NB-TDD) system.

FIG. 2 illustrates a sub-frame structure in a narrowband time division duplexing (NB-TDD) system. FIG.

FIG. 3 is a diagram illustrating a method for allocating uplink and downlink channels to UEs in a narrowband time division duplexing (NB-TDD) system.

4 illustrates a structure of a time slot in a subframe of FIG.

5 shows the structure of a DwPTS;

6 is a diagram illustrating the structure of an UpPTS.

7 is a diagram illustrating an apparatus for transmitting and receiving a mobile station (UE) according to an embodiment of the present invention.

8 is a diagram illustrating a configuration of a DwPTS arrival time difference estimator for UE location estimation according to an embodiment of the present invention.                 

9 is a diagram illustrating an apparatus for transmitting and receiving a base station in a narrowband time division duplexing system according to an exemplary embodiment of the present invention.

10 is a diagram illustrating a flow of a UE location estimation process in a terminal of a narrowband time division duplexing (NB TDD) system according to an embodiment of the present invention.

11 is a diagram illustrating a flow of a UE location estimation process in a base station in a narrowband time division duplexing system according to an embodiment of the present invention.

12 is a view for explaining a method for measuring Observed Time Difference Of Arrival position in a narrowband time division duplexing system according to an embodiment of the present invention.

The present invention relates to a method and apparatus for estimating the position of a terminal in a narrowband time division duplexing code division multiple access communication method in a third generation mobile communication system using a code division multiple access method. The third generation mobile communication system uses a frequency division duplexing communication system (FDD) for distinguishing up and down transmissions by frequency, and a wideband time division multiplexing communication system for distinguishing uplink and downlink transmissions by time. Time division duplexing communication system (hereinafter referred to as WB-TDD) and NB-TDD, and the broadband time division multiple communication scheme and the frequency division multiple communication scheme use 3.84 MHz at a chip rate. Uses a chip rate of 1.28 MHz.

Brief description of the NB-TDD mobile communication system for the convenience of description of the present invention is as follows.

FIG. 1 is a diagram illustrating a configuration of a radio access network (hereinafter referred to as a RAN) in an NB-TDD. The upper concepts of a network such as the RAN and a core network (hereinafter referred to as a CN) are UTRAN. (UMTS Terrestrial Radio Access Netwrok).

1, reference numeral 100 denotes a RAN. The RAN 100 includes a plurality of RNCs (hereinafter referred to as RNCs), a plurality of Node-Bs connected to the RNCs by wire, and terminals (user equipments (hereinafter referred to as UEs)). The RNC 110 and 120 of FIG. 1 respectively control a plurality of node Bs (called base stations). The nodes B 111, 112, 121, and 122 of FIG. 1 are connected to a plurality of UEs, respectively, and the node B exchanges an uplink signal and a downlink signal using a radio frequency with the UE. The UE 113 and the UE 123 of FIG. 1 are terminals used by a user, and transmit user information and higher layer signaling information to the UTRAN through node B, and user information and higher layer signaling information transmitted through node B in UTRNA. Receive.

2 is a diagram illustrating a sub-frame structure of NB TDD. The two subframes are 10ms long and become a radio frame, which is a basic unit of wireless transmission, in the 3rd generation asynchronous mobile communication system. The 10ms long radio frame is a basic unit of wireless transmission commonly used in FDD, WB-TDD, and NB-TDD.

 The subframes used in the NB-TDD shown in FIG. 2 include seven time slots, a forward pilot time slot (DwPTS), and an uplink pilot time slot (UpPTS). It is composed of In FIG. 2, a time slot with a down arrow is a section for transmitting a signal from a base station to a UE, and a time slot with a up arrow is a section for transmitting a signal from a terminal to a base station. In NB-TDD, since uplink and downlink transmission is changed in units of time slots, several rules are applied to allocate time slots of subframes to uplink and downlink transmission. 201 of FIG. 2 should be used only for downlink transmission with time slot 0. 202 DwPTS is a period in which a base station transmits a pre-promised code sequence to synchronize the UE, and 204 UpPTS is used for backward synchronization. A terminal transmits a predetermined code sequence previously promised to a base station. 210 in FIG. 2 indicates a time point at which up and down transmissions are switched to the switching point. The guard period 203 of FIG. 2 (hereinafter referred to as GP) is a period set so that DwPTS and UpPTS overlap each other so as not to interfere with each other. The 211 switching point is a time point for distinguishing up and down transmission of time slots other than TS0 of the NB-TDD subframe of FIG. 2. The 211 switching point is set to have a large number of uplink slots when there is a large amount of data to be transmitted upwards, and to set a large number of downlink slots when there is a lot of data to be transmitted downwards.

3 is a diagram illustrating a method for allocating uplink and downlink channels to UEs in an NB-TDD system. For convenience of explanation, it is assumed that the uplink channel between the base station and one UE is allocated. 3, 301, 302, 303, and 304 are radio frames, 311 and 312 are two subframes of a radio frame 301, 321 and 322 are two subframes of a radio frame 302, and 331 and 332 are two subframes of a radio frame 303. 341,342 are two subframes of the radio frame 304.

In FIG. 3, when the UE requests the base station to allocate a channel or when the base station allocates a channel to the UE, the base station uses resources such as radio frames, subframes, timeslots, channel codes, and the like for uplink transmission. The UE informs the UE of resources such as radio frame, subframe, time slot, channel code, and the like for downlink transmission. Among the resources used for the channel allocation, the channel code is an orthogonal code and distinguishes downlink transmission channels using the same timeslot in the case of downlink transmission, and different UEs using the same timeslot in the uplink transmission. It serves to distinguish. In the up-and-down transmission through the orthogonal code, one or more channel codes may be allocated to the same UE to increase the transmission rate of the downlink transmission and the uplink transmission to the UE. The channel code used in NB-TDD uses an orthogonal variable spreading code (hereinafter referred to as an OVSF code) used in a 3rd generation asynchronous mobile communication system. The characteristic of the OVSF code is that the length and number change according to the spreading rate for spreading the data. For example, if the spreading rate is 4, the data is expanded by four times the bandwidth. In this case, the length of the channel code used is 4, and four channel codes having a spreading rate of 4 are generated. The spreading rate of data used in NB-TDD is 1,2,4,8,16, and as the spreading rate increases, the transmission rate of the transmitted data is lowered.

In FIG. 3, a method of determining an uplink channel between a base station and a UE sets a downlink channel to a specific channel code in a time slot used for downlink transmission among time slots of 311 subframes and transmits uplink among time slots of 311 subframes. This is to set up channel to specific channel code in time slot used for. The uplink and downlink channels established between the UE and the base station may be repeated every radio frame unit, and the uplink and downlink channel between the UE and the base station may be reset after a certain radio frame. How many times the uplink channel between the UE and the base station is repeated or how many radio frames are reset may depend on the nature and amount of data transmitted between the UE and the base station. In addition, when there is a lot of uplink data and little data to be transmitted downlink, the uplink transmission channel may be repeated more frequently than the downlink transmission channel. In FIG. 2, the 204 frame refers to a frame in which data transmission between the UE and the base station is terminated.

FIG. 4 is a diagram illustrating a structure of a time slot in a subframe of FIG. 3 and is used in the same way for uplink transmission and downlink transmission. The data parts 411 and 417 of FIG. 4 are used for transmission of data to be transmitted upward or downward, and 412 and 416 are TFCI parts for transmitting a Transport Format Combination Indicator (TFCI), wherein the TFCI is a base station to a UE. If there is a data rate of the downlink channel transmitted to or a downlink channel transmitted by several channel codes, it serves to inform the data rate and the nature of the data of each channel code, and also the case of the uplink channel. The 413 midamble of FIG. 4 is used to distinguish UEs using the same timeslot or uplink base station channels using the same timeslot for uplink transmission in WB-TDD and NB-TDD among 3G asynchronous mobile communication standards. In this case, it is used for channel estimation in uplink and downlink transmission. The downlink transmission is used to measure the loss due to the channel path from the base station to the UE and to distinguish the base stations due to the use of different midambles. A specific sequence is used for the 413 midamble unit, and there are 128 kinds of specific sequences. The channel code and the midamble sequence described in the description of FIG. 3 have different characteristics and types. When the uplink transmission is taken as an example, the channel code is an orthogonal code used for the data parts 411 and 417 of FIG. 4 and transmitted to the data parts. The midamble plays a role of distinguishing which UE is transmitting, and the midamble is not spread using a channel code.

The 414 SS (Synchronization Shift: hereinafter referred to as SS) of FIG. 4 is used to transmit a command for adjusting synchronization when synchronization is out of synchronization due to a change in distance between the UE and the base station or other reasons during transmission. By the command transmitted to the SS, the UE can adjust synchronization in units of 1/8 chip.

The 418 GP of FIG. 4 is a section for distinguishing between the currently transmitted slot and the next transmitted slot, and the GP has an uplink transmission slot followed by a downlink transmission slot or a downlink transmission slot after a downlink transmission slot. In this case, it serves to distinguish each other from becoming an interference signal.

The TPC (Transmit Power Control Commander, hereinafter referred to as TPC) of FIG. 4 is used to control downlink transmission power of a base station when the TPC is transmitted upward, and is used to control downlink transmission power of a UE when transmitted downward. Used for control

FIG. 5 is a diagram illustrating the structure of a DwPTS. The DwPTS includes a GP and a SYNC DL (SYNC DL), and transmits a DwPCH (DwPCH, hereinafter referred to as DwPCH). It can be used for initial cell search and down synchronization. The length of the 501 GP of FIG. 5 is 32 chips, which exists in front of the SYNC DL, and serves to prevent the signal of the SYNC DL code and the time slot 0 from overlapping. Base stations use different SYNC DL codes.

FIG. 6 is a diagram illustrating a structure of an UpPTS. UpPTS is also composed of a GP and a SYNC UL (hereinafter referred to as SYNC UL), and transmits an UpPCH (Uplink Pilot Channel: hereinafter referred to as UpPCH). The length of the 602 GP of FIG. 6 is 32 chips, similar to the 501 GP of FIG. 5, and its position is located behind the SYNC UL, unlike DwPTS. The 601 SYNC UL code of FIG. 6 has a length of 128 chips and has a total of 256 codes. The purpose of the 601 SYNC UL code is to use the base station to measure UpPCH to synchronize uplink of the UE.

Accordingly, an object of the present invention is to propose a method for estimating the position of a UE in the NB TDD system described above. The location tracking of a UE is performed by the UE measuring a signal from each base station or a GPS (Global Positioning Syetem (GPS) satellite signal) to directly calculate its own location or reporting the measurement to the base station so that the base station can locate the UE. It is to provide an apparatus and method for identifying the.

Another object of the present invention is to provide an apparatus and method for identifying a location of a UE for providing emergency contact service or vehicle location tracking in the narrowband time division duplexing system.

It is still another object of the present invention to provide an apparatus and a method for better determining the location of a UE using DwPCH of NB-TDD, and measuring a signal of DwPCH better using a signal canceling method.
In the mobile communication system according to the present invention, a method for estimating the position of a terminal may include receiving pilot channel signals from a serving base station and a plurality of neighbor base stations of the terminal during a specific downlink signal period, and receiving from the serving base station. When the power of the received pilot channel signal is greater than a preset threshold, the pilot signal received from the serving base station is removed by removing the pilot signal received from the serving base station from the pilot channel signals received from the serving base station and the plurality of neighbor base stations. Outputting a channel signal and outputting a pilot channel signal received from the serving base station and the plurality of adjacent base stations when the power of the pilot channel signal received from the serving base station is less than a preset threshold, and outputting the output pilot channel Signals After decoding, after calculating a time difference between pilot channel signals having a power greater than a predetermined minimum power among the decoded pilot channel signals, the serving base station and the location estimation information including the time difference between the pilot channel signals are calculated. And transmitting to at least one base station among a plurality of neighboring base stations, and estimating the position of the terminal using the position estimation information at the base station receiving the position measurement information.
In addition, the terminal apparatus for estimating the position of the terminal according to the present invention includes a receiver for receiving pilot channel signals from a serving base station and a plurality of neighbor base stations of the terminal during a specific downlink signal interval, and a pilot received from the serving base station. A determiner that compares a power of a channel signal with a preset threshold and determines whether to remove a pilot signal received from the serving base station from pilot channel signals received from the serving base station and a plurality of adjacent base stations; The serving base station is determined to remove the pilot signal received from the serving base station from the pilot channel signals received from the serving base station and a plurality of neighboring base stations according to the power of the pilot channel signal received from the base station greater than a preset threshold. And A cancel unit which removes pilot signals received from the serving base station from pilot channels signals received from a plurality of neighbor base stations and outputs pilot channel signals received from the plurality of neighbor base stations, and the plurality of neighbors output from the remove unit Receives at least one of a pilot channel signal received from a base station and a pilot channel signal received from the serving base station and a plurality of neighboring base stations, decodes the transmitted pilot channel signals, and power of the decoded pilot channel signals is reduced. After calculating a time difference between pilot channel signals having a power greater than a predetermined minimum power, the position estimation information including the time difference between the pilot channel signals for transmission to at least one of the serving base station and the plurality of neighboring base stations is obtained. Output time difference calculator It includes.
In addition, the base station for estimating the position of the terminal according to the present invention includes a receiver for transmitting a pilot channel signal during a pilot channel signal transmission slot, and receiving position measurement information including a time difference between the pilot channel signals from the terminal; And a position estimator for estimating the position of the terminal using the received position estimation information.

Hereinafter, with reference to the accompanying drawings to aid in the detailed description and understanding of the present invention.

The present invention relates to a method and apparatus for enabling UE location estimation in NB TDD. The present invention relates to 3GPP (3GPP), which is a standard organization of the third generation asynchronous mobile communication method. What is set as a method to enable position estimation is largely divided into three techniques. The three technologies are referred to as a cell based method, an observing time difference of arrival method (hereinafter referred to as an OTDOA method), and a method using GPS (Global Positioning System). It is called. The cell-based method is a method for estimating the location of a UE by assigning an identifier to a base station communicating with the UE, determining which base station the UE belongs to, and the OTDOA method is a signal transmitted from each base station by the UE. It is a method of estimating the position of the UE by measuring the arrival time of them, and the method using GPS is a method of estimating the position of the UE using a signal transmitted from a GPS satellite in the earth orbit. The present invention is a technique applied to the technique of estimating the position of the UE by measuring the signal, such as the method using the OTDOA method and GPS among the three methods.

In order to estimate the location of the UE, the UE needs to measure information indicating its location, and can calculate the location of the UE based on the measurement result. The location calculation of the UE may be performed directly at the UE, or may be performed at the base station side by transmitting the measurement information to the base station. The method of directly calculating the position of the UE by the UE is called a UE based method, and when using the UE based method, the UE should know information about the position of a signal measurement source that sends a signal measured by the UE itself. The method of calculating the position of the UE at the base station in transmitting the information measured by the UE to the base station is called a UE based method. The location calculation of the UE is performed in a device capable of UE location measurement at the base station, and the location of the device capable of location estimation of the UE is a SRNC (Serving Radio Network Controller: S-RNC) to which the UE is connected. It may be located at any location in the upper network.

In order to help the understanding of the present invention, the OTDOA method of the location estimation method of the UE will be described with reference to FIG. 12.

Before describing FIG. 12, it is assumed that three base stations exist around the UE. For convenience of description of the present invention, in FIG. 12, the number of base stations is limited to three. In a real environment, when using OTDOA, there may be at least three base station signals. In FIG. 12, the UE 1201 receives downlink signals from node B (a) 1211, node B (b) 1212, and node B (c) 1213. Since the distance is different, the UE arrives with a relative time difference. The relative time difference is a value that depends on the distance between the UE and node B, but may also be dependent on the channel environment between the UE and node B. Since the time difference due to the channel environment is relatively small, it may bring an error in the position estimation of the UE, but does not have an absolute effect. The UE 1201d measures a time difference of signals from each node B, reports the measured values to a base station, or directly calculates a location. With the time difference of the signals measured by the UE, a method of estimating the position of the UE is to use a hyperboloid shown in FIG. 12. That is, from among the signals received from the respective Node Bs, the time difference is calculated by measuring the reception time of the signals of the base station received after that point, from the first signal arriving at the UE. By using the calculated time difference, a method of drawing a hyperbolic curve with two node Bs where the time difference occurs as a vertex is repeated, and the intersection point of the hyperbolic curve is estimated as the region where the UE exists as shown in FIG. . The accuracy of the position estimation of the UE is determined by the precision of the signal to be measured. The signals used for the location estimation of the UE are different in each of 3GPP technologies, that is, FDD, WB-TDD, and NB-TDD, but the common point is that a UE receiving a signal distinguishes it from signals from other node Bs. It should be a signal that can be, and should be a signal that must be continuously transmitted from the node B.

Since the NB TDD system to which the present invention is applied uses a special subframe structure as described in the above description of the prior art, since all node Bs in the NB-TDD system are synchronized, the DwPCH transmitted in the DwPTS is transmitted to the UE. Is used as a signal to be measured, but other signals with requirements that the UE can use for the above-described position estimation do not limit the application of the present invention.

The DwPCH is a signal that is repeated every 5 ms subframe, and is a signal that can be sufficiently identified by the UE because different Sync-DL codes are used for each base station around the UE. Another reason for using the DwPCH as a signal for measuring is that as described above, the frame synchronization of all node Bs in the NB-TDD coincides with each other, so that at the time when one node B transmits the DwPCH in the DwPTS, all other base stations are used. This is because they transmit DwPCH. That is, from the standpoint of a UE that needs to measure a signal for position estimation, since only the DwPCH signal required by the UE exists during the DwPTS period, measurement interference by other downlink channels is not received.

The present invention proposes a signal removal method and apparatus in order to facilitate the measurement in measuring DwPCHs or other signals of respective Node Bs to be measured by the UE.

The first problem in using the OTDOA method is that when the UE is located near node B, it is difficult for the UE to measure signals other than the signal of node B because the signal strength of the node B is strong. That is, in order to use the OTDOA method, signals of three or more node Bs must be measured, but UEs near node B are difficult to receive signals of other node Bs due to the signal of the node B, or to the node B. If you are very close, you cannot receive signals from other node Bs.

In general, the signals received by the UE are mathematically represented by Equation 1 below.

 Io = Ior + Ioc

In Equation 1, Io means all signals received by the UE, and Ior node B, which transmits a self-signal to be received by the UE, that is, a common channel including system information of a dedicated channel or a base station to the current UE. Is a downlink signal, and Ioc means all other signals except for the signal of node B or node B, and also includes noise. The method proposed by the present invention provides a method of removing the Ior, the size of which is increased in Equation 1, when the UE is located near a certain node B or moves near the node B. The signal measurement of other base stations included in the Ioc of 1> is facilitated. The signal of the other base stations may be DwPCH in the NB-TDD communication system.

Hereinafter, detailed operations and principles of the present invention will be described with reference to FIGS. 7, 8, and 9.

FIG. 7 illustrates an example of a structure of a transmitter and a receiver of a UE according to the present invention. The transmitter transmits an uplink physical channel, which is an uplink transmission channel transmitted from a UE to a node B, and receives a downlink physical channel transmitted from a node B to a UE. A diagram illustrating a receiver. In the NB-TDD mobile communication system, since the same frequency band is used for the up-and-down transmission, the transceiver may be distinguished and used as a switch. In FIG. 7, a UE transceiver will be described on the assumption of an I / O user up / down transmission / reception process.

The 701 i-th user data of FIG. 7 includes signaling information of the upper layer and data information of the user. The 701 i-th user data is encoded through a 702 encoder. The encoding is used to increase the reliability of data transmission. When an error occurs during data transmission, the encoding is used to detect or correct the error. Convolutional coding and turbo coding are the most commonly used coding methods, and other channel coding methods may be used. The i-th user data encoded through the encoder 702 is interleaved in the interleaver 703. The interleaving is a process for reducing the influence of the error on the data for the time-intensive error when the error occurs continuously in the i-th user data transmitted on the physical channel. The interleaving is to change the transmission order of the user data according to a predetermined rule when transmitting the i-th user data. Even when a concentrated error due to narrowband noise occurs in the transmission process, each error is deinterleaved at the receiving end. Due to the spreading of these positions, the influence of the concentration error caused by the narrowband noise is minimized.

The i-th user data that has passed through the interleaving 703 is input to the 707 multiplexer, whereby the 704 transmission format combination indicator (hereinafter referred to as TFCI), 705 SS (synchronization shift: referred to as SS), and 706 TPC (Transmit Power) control Command: hereinafter referred to as TPC) and multiplexed to become the user's data part. The 704 TFCI is an indicator indicating a data rate and a combination of transmissions of various types of user data, for example, voice information and packet information, so that node B can correctly interpret the data. . 705 SS is a command transmitted for each subframe and used to adjust downlink synchronization as described in FIG. 706 TPC is used for control of downlink transmission power from node B to UE as a command for power control. The user data unit generated by the 707 multiplexer is input to the 708 spreader and multiplied by a channelization code. In the NB-TDD communication system, an OVSF code (hereinafter referred to as an OVSF code) is used as the channel code. The OVSF code is a kind of orthogonal code whose length is determined according to a data rate. The channel code distinguishes an uplink channel of each user when several users simultaneously transmit data in one time slot in an NB-TDD communication system, and the data of the user depends on the length of the channel code. Spreads the band to be transmitted. The spreading rate of the transmission band is called spreading rate, and the product of the spreading rate and the transmission rate of user data is 1.28 mcps, which is the chip rate of the NB-TDD communication system. The i th user data portion spread in the 708 spreader is multiplied by the channel gain in the multiplier 709. The channel gain is a value used to determine the transmit power of the uplink channel from the UE to the base station. The i-th user data portion output from the multiplier 709 is multiplied by a scrambling code (hereinafter, referred to as a scrambling code) in the multiplier 710. The scrambling code is a code used in the 3rd generation asynchronous mobile communication standard, and is used to reduce cross-correlation of node B or base station and user, and multipath of the same signal. In the Nb-TDD communication system, it is used only to reduce the discrimination and cross-correlation of base stations. In the NB-TDD communication system, one scrambling code is used for each base station, and the scrambling code is used for up and down transmission. The i-th user data portion scrambled by the multiplier 710 is input to the multiplexer 711 to be multiplexed with the midamble 714 to form an i-th user upstream channel. The i-th user data part multiplexed by the multiplexer 711 is divided into two parts, and the midamble is inserted between the i-th user data part divided into the two parts. The uplink time slot includes a user data unit, a midamble, and a guard period. A description of the user data unit has been described above in the multiplexer 707, and the description of the midamble has been described above with reference to FIG. . The guard interval is intended to prevent interference between uplink and downlink transmissions by overlapping uplink transmission slots and downlink transmission slots in an NB-TDD communication system, and even if the next time slot is the same uplink transmission time slot, Since the positions are different from each other, the uptime slots are created for the purpose of preventing interference, and virtually nothing is transmitted in the guard interval.

 The i-th user upstream channel output from the 711 multiplexer is modulated by the 712 modulator. In the NB-TDD communication system, Quadrature Phase Shift Keying (QPSK) or 8 Phase Shift Keying (8PSK) is used as the modulation scheme, and other QAM (Quardrature Amplifire Modulation) may be used. The i-th user upstream channel output from the 712 modulator is input to the switch 720 and transmitted to node B in a time slot in which the user uplink channel is transmitted.

The switch 420 is controlled by the controller 421, and the controller 421 adjusts a time point at which an uplink channel is transmitted, and transmits an UpPTS, a DwPTS, and a node B according to a subframe structure of the NB-TDD system. The switch 420 is controlled according to the downlink channel reception time of the switch 420. The UpPTS is generated through the UpPTS generator 413. The UpPTS is transmitted when the UE needs to allocate a channel from a base station or in a handover situation. Used to adjust.

The user upstream channel output from the switch 720 is raised to a carrier frequency band through the RF unit 422 and transmitted to the node B through the antenna 723, and the signal transmitted to the node B is transmitted to the UTRAN.

The process of receiving the down channel of the i-th user in the UE transceiver structure diagram of FIG. 7 is as follows.

The downlink channels received through the antenna 723 of FIG. 7 are lowered from the carrier band to baseband frequency through the RF device 722 and input to the switch 720. The switch 720 is connected to the demodulator 432 when it is time to receive the downlink channel by the controller 721. Signals received by the UE of the user from the node B may include DwPTSs transmitted by the node B and DwPTSs transmitted by other node Bs. The switch 720 is connected to the DwPTS analyzer 731 and the reception signal arrival time measuring instrument 744 at the time of receiving the DwPTS, and inputs the received DwPTSs to the DwPTS analyzer 731 and the reception signal arrival time measuring instrument 744. The DwPTS has a location of a primary common control channel (hereinafter referred to as P-CCPCH), which is a physical channel through which a UE receives a base station discovery process and transmits a broadcasting channel containing system information. The UE informs which position the UE is currently receiving a downlink frame in a multi-frame structure, and simultaneously measures downlink channel synchronization. In the NB-TDD, when a base station transmits and receives data, a predetermined number of radio frames (10 ms units) are scheduled and used together. Typically, 64 radio frames or 72 radio frames form one multi-frame structure. In addition, in the present invention, in addition to the DwPTS transmitted from the node B, another DwPTS is also input to the reception signal arrival time measuring instrument 744, and the reception times of the DwPTSs are calculated. The detailed structure of the received signal arrival time measuring instrument 744 is shown in FIG. 8. In addition, the DwPTS analyzer 731 of FIG. 8 may be a correlator or a matched filter.

In the demodulator 432 of FIG. 7, the downlink channel is demodulated again according to the modulation scheme used by node B and inputted to the demultiplexer 733. The demultiplexer 733 divides the downlink channel into a midamble and a user data unit, and the separated midamble 734 enables the measurement of the received power of the downlink channel transmitted from the base station. It is possible to know what is there, and the interpretation of the midamble 734 also enables the determination of whether or not there is data transmitted to the UE.

The downlink data portion output from the demultiplexer 433 is input to a multiplier 735, and the multiplier 735 performs a demixing process of multiplying a demodulated downlink data portion with a scrambled code used in the node B. The demixed data Is input to despreader 736. The despreader 736 distinguishes the downlink common channel 737 through which the i-th user data and the base station system information or the UE control information are transmitted to the downlink data unit, and despreads the spread i-th user data and the downlink common channel. . In the despreader 736, the base station multiplies the i th user data part by the OVSF code used for the downlink common channel to perform the same function as described above.

The user data output from the despreader is input to the demultiplexer 738 and separated into TPC 739, TFCI 740, SS 770, and pure user data. The TPC 739 is used to control transmission power of an uplink channel to be transmitted by the user's UE, and the TFCI 740 is used to distinguish and interpret the type of data transmitted from the base station to the i th user. It is used as a command to request synchronization adjustment of uplink channel. The pure i-th user data output from the demultiplexer 738 is deinterleaved by the deinterleaver 741, after the concentrated errors generated during downlink transmission are distributed, inputted to the decoder 742, decoded, and then the i-th user data 743 is obtained. Used.

8 is an example of the received signal arrival time measuring instrument 744 of FIG. 7.

The received signal arrival time estimator of FIG. 8 uses DwPCH of neighboring Node Bs of the UE equipped with the received signal arrival time estimator, but as described above, the arrival of other signals that can be used for position estimation of the UE. The time can also be estimated. The condition for estimating the arrival time of the other signals is that the UE having the received signal arrival time estimator knows the transmission conditions of the other signals, i.e., the position of the scrambling code and the channel code and the time slot in which the other signals are transmitted. .

In the description of the present invention, the signal arrival time of the DwPCH is estimated.

The received signal arrival time estimator of FIG. 8 inputs DwPCHs of other node Bs including the output signal 803 of the DwPTS analyzer 731 of FIG. 7 and the received signal output from the switch 720 of FIG. 7, that is, the DwPCH of node B to which it belongs. As a result, the arrival time of each DwPCH is measured.

 The determiner 804 of FIG. 8 receives information on the DwPTS of the node B to which the current UE belongs from the DwPTS interpreter 731 of FIG. 7 to determine whether to subtract the DwPTS signal of the node B from the received signal 801. The DwPTS information of the node B to which the UE belongs refers to the magnitude of the received power of the DwPTS and the arrival time measurement of the DwPTS. The magnitude of the received power of the DwPTS is used to remove the node B signal from the received signal of the current UE, and the arrival time measurement of the DwPTS is used to obtain the arrival time difference of the received DwPTS in the time difference calculator 810.

The reason for using the 804 determiner of FIG. 8 is that in this method, the UE uses a signal cancellation method to smoothly receive DwPTSs. The principle of the signal removal method is to remove components having the largest magnitude among received signals one by one. It is. In order to effectively perform the signal removal method, the larger the difference between the components of the received signal is, the better. If the components of the received signal are similar in size, in the process of removing the components of the received signal one by one, other received signal components that are not removed in the process of removing any signal components may also be partially removed. Performance may be degraded than if the size difference is large. Therefore, in the present invention, in consideration of the reception signal size of the DwPCH of the Node B to which the UE currently belongs, if the reception signal size of the DwPCH is large enough, the reception time of the reception signals of other DwPCHs is measured using a signal removal method, and the DwPCH If the magnitude of the received signal is not large enough, the arrival time of each DwPCH is measured for the entire received signal including the DwPCH of the node B. The criterion for determining whether to use the signal removal method may be the size of the DwPCH of the Node B to which the UE belongs, measured in the UE, in which case the transmission power of the DwPCH should be known to the UE in advance. Another criterion may be a method of comparing the received powers of all DwPCHs received by the UE. In the method of comparing the received powers of the DwPCH, one more interpreter of the DwPCH is needed in FIG. 8. The added DwPCH interpreter is an interpreter for analyzing all DwPCHs received by the UE, and the DwPCH interpreter 808 of FIG. 8 serves as an interpreter for interpreting another DwPCH from which the DwPCH signal of node B to which the UE belongs is removed. In FIG. 8, it is assumed that the determiner determines whether to use a signal removal method or not based on the size of the DwPCH measured by the UE.

When it is determined in the determination unit 804 of FIG. 8 that the signal removal method is used, the determination unit 804 controls the switch 802 to connect the received signal 801 to the summer 807. The determiner 804 also outputs the received power of the DwPCH to the multiplier 805 at the output 803 of the DwPTS analyzer. The magnitude of the DwPCH output to the multiplier 805 is multiplied by the DwPCH code of 808. The multiplied DwPCH becomes a UE received signal of the DwPCH of the base station to which the current UE belongs, and is input to the summer 807, but is changed to a negative value. The summer 807 removes the reception DwPCH of the node B to which the current UE output from the multiplier 805 belongs in the reception signal 801.

The signal output from the summer 807 is input to the DwPCH analyzer 808 and used to estimate the arrival time of each DwPCH constituting the signal. The DwPCH interpreter 808 may use a correlator or a matched filter. The Sync_DL codes to be used for the analysis of the DwPCH may be informed by node B (base station side), or all 32 Sync_DL codes in the UE may be used. The codes reported by the base station are Sync_DL codes of neighboring base stations known by the base station, and when the SYNC_DL codes are known to the UE in advance, the execution time in the interpreter 808 of the DwPCH may be reduced. In addition, even if the DwPCH analysis is performed on all 32 Sync_DL codes known to the UE, no particular problem occurs. The output of the DwPCH interpreter 808 is a time indication value for the time interval for when the DwPCH was received during a predetermined length of time interval received by the UE and the size of each DwPCH. The output of the DwPCH analyzer 808 is input to a power comparator 809, which is compared with a threshold in the power comparator, so that DwPCH measurements that do not exceed the threshold are not used. The reason for using the power comparator 809 is that if the size of the DwPCH measurement interpreted by the DwPCH analyzer 808 is too small, the DwPCH measurement may be interpreted as DwPCH, but the error may be interpreted and changed to a DwPCH measurement. If the error is used to estimate the location of the UE, the error may also occur in the location estimation of the UE, so that the DwPCH estimate that is not larger than a certain size may be removed to increase the reliability of the location estimation of the UE. The threshold value of the power comparator may be a value determined by the UE at its own control, and may also be a value comparing the magnitude of the received power of the DwPCHs received by the UE. That is, as an example, if the UE has a received signal power of node B to which the current UE belongs to 1, and the received power of another DwPCH is less than 0.1 with respect to 1, the estimate of the DwPCH may not be used. have.

The DwPCH arrival time estimate passing through the power comparator 809 is input to a Time Difference Calculator 810 to calculate all time differences by selecting two of the signals arriving during a predetermined time interval when the UE receives the DwPCHs, and calculating the DwPCH. Report the reception time difference of the UE to the upper layer. Although the time difference may be selected by comparing the same two DwPCH, since the two two DwPCH is received through the multi-path may have a certain range rather than a specific value. The received time differences of the reported DwPCH output from the time difference calculator 810 may be used to estimate the position of the UE within the UE itself, and are transmitted to the base station side by higher layer signaling in the form of a UE measurement report message. It can be used to calculate the location of the UE at the base station side.

9 is an example of a transceiver diagram of a base station corresponding to FIG. 8.

Referring to FIG. 9, the Node B transmits a downlink channel to UEs in the Node b. In the following description, in order to facilitate the understanding of the present invention, a part of transmitting to one user is described in detail, but the method of transmitting a downlink channel to another user in node B is the same as the method described with reference to FIG.

9, 901 of FIG. 9 is downlink data to be transmitted to the i-th user. The downlink data 901 is channel-coded via the encoder 902 and then input to the interleaver 903. In the multiplexer 906, the TPC 905 for controlling the uplink transmit power of the i-th user UE and the TFCI 904 indicating the transport format used for the i-th user data are transmitted from the UE. The SS 960 and the i-th user data which require synchronization adjustment of the uplink transmission channel of the multiplexed multiplexer are multiplexed to become the i-th user data unit.

The data unit is spread by the OVSF code used for the downlink channel of the i-th user in the spreader 907, and then multiplied by the channel gain for the downlink channel transmission power to be transmitted to the i-th user in the multiplier 908. 911).

The adder 911 receives the downlink common channel 910, the other user channel 909, and the i-th user channel as inputs, and the channels are each channel spread with different OVSF codes, which are added together. It does not affect other channels. The downlink channel signals output from the summer 911 are mixed with the scrambling code used by the base station in the multiplier 912 and then input to the multiplexer 914. The multiplexer 914 multiplexes the downlink channel signals and the input midamble 913 to generate a downlink channel slot. The midamble 913 may be used when the UE receiving the midamble 913 estimates the size of the base station transmit power, and determines which channels are transmitted to the multiplexed downlink slots in the multiplexer 914. It is used to find out.

The output of the multiplexer 914 is input to a modulator 915. The modulator 915 modulates the input down channel signals, and QPSK, 8PSK, QAM, etc. may be used as a modulation scheme. The modulated downlink channel signals are input to a switch 920. The switch 920 is connected to the demodulator 915 at the time of transmission of the downlink channel slot under the control of the controller 921, and the downlink channel slot is RF. Send to machine 922. The switch 920 is connected to the DwPTS generator 916 under the control of the controller 921, and transmits the DwPTS at the time when the DwPTS is transmitted. The DwPTS is a base station during the initial base station discovery process by the UE receiving the DwPTS. It is used to estimate the location of the broadcasting channel containing the information, the size of the base station signal, and the location of the frame currently being received in the multiframe. In addition, in the present invention, the DwPTS is also used as data of the position estimation of the UE. The RF device 922 of FIG. 9 converts the downlink channel slot into a carrier band and then outputs it to the antenna 923, and the antenna 923 transmits the downlink channel slot to UEs in a base station. .

Referring to FIG. 9, a process of receiving an uplink signal from UEs in a base station is as follows. The uplink signals received through the antenna 923 of FIG. 9 are converted from the carrier band to the baseband through the RF device 922 and then input to the switch 920. The switch 920 inputs uplink signals received from the UE to the demodulator 931 at a predetermined time according to the controller 921. The controller 921 grasps a time point at which UEs in the base station transmit an uplink channel signal, controls the switch 920, and connects the switch 920 to the UwPTS interpreter 930 according to the reception time point of the UwPTS. It also has a function that enables the interpretation of UwPTS transmitted from each UE.

The demodulator 931 of FIG. 9 demodulates the input upstream signal and inputs the same to the multiplexer 932. The multiplexer 932 of FIG. 9 serves to separate the midamble 933 and the uplink signal data unit from the received uplink signals, and the midamble 933 is a user joint detection and a channel environment between the UE and the base station. It is used for estimating and estimating the magnitude of the transmission signal of the UE. The uplink signal data portion output from the multiplexer 932 is input to the multiplier 934 and multiplied by the scrambling code used in the UE transceiver of FIG. 4 to be demixed. The demixed uplink signal data unit is input to the despreader 935 so that the uplink signal data unit is separated for each user, and the uplink signal data unit of the i-th user is input to the multiplexer 936. The demultiplexer 936 separates the TPC 937, the TFCI 938, the SS 970, and the i-th user's data from the i-th user's uplink data portion, and the TPC 937 is a downlink transmit power controller ( 980 is used to control the downlink transmission signal power of the i-th user, the TFCI 938 is used to interpret the transmission format used in the data portion of the i-th user, and the SS 970 is directed down to the UE. Used to adjust the transmission timing of the channel. The i-th user's data output from the demultiplexer 936 is inputted to the deinterleaver 939 and deinterleaved, and then input to the decoder 940 to be decoded to become the i-th user's data 941. The other user uplink channel 950 output from the despreader 935 is also received by the base station through the same process as the i-th user data. The I-th user data includes measurements for calculating the location of the UE or the location of the UE received from the UE, and the measurements for calculating the location of the UE are input to the UE location calculator 942. The UE location calculator 942 may be located in the base station, may be in the SRNC to which the UE is currently connected, or may be located at any point in the UTRAN.

The method performed by the 942 user location calculator of FIG. 9 most typically uses an Observed Time Dirrerence Of Arrival (hereinafter referred to as OTDOA). In using the OTDOA, the measurement used in the present invention is a difference in the reception time of the DwPCH received during a certain reception time interval of the UE. In addition, information about the distance between each base station should be given in order to calculate using the OTDOA method. The UE calculates the difference between signals from the base station (or cell) to which it belongs and other base stations (or cells), so the information given by the measurement only shows how far the UE is from each base station. In order to use the OTDOA method, the base stations transmitting the DwPCH received by the UE are fixed to one vertex, hyperbolic curves representing the same distance around the vertex are selected, and the hyperbola is selected by a distance that is calculated by the UE. The intersection of the hyperbolas of each base station is estimated as the location of the UE.

10 is a flowchart illustrating a UE location estimation process of a terminal.

If the control information of the upper layer to the position measurement to the UE comes to 1001 start step. In step 1002, the UE interprets the DwPCH of the cell to which it belongs. In step 1003 of determining the analyzed DwPCH power, the power of the DwPCH is compared with the threshold 1. The threshold 1 moves to step 1004 if the detected DwPCH power is greater than the threshold 1 as the threshold value for the base station DwPCH power to which the current base station belongs. In step 1004, since the DwPCH power of the current base station is sufficiently large and determined to be close to the UE base station, a process of generating a DwPCH signal of the current base station and removing it from the received signal is performed. After removing the DwPCH signal of the current base station, it moves to step 1005. Step 1005 is a process of decoding the DwPCH signal and may immediately come from step 1003 or may go through step 1004. The signal that has passed through step 1004 is a signal from which the DwPCH of the base station to which it currently belongs is removed. Therefore, the result value of step 1005 detects only the DwPCH signal of the neighboring base station except the DwPCH of the current base station. On the other hand, if the command to move directly from step 1003 to step 1005, the result value after the DwPCH decoding in step 1005 includes the DwPCH of the current base station and the DwPCH signal of the remaining neighboring base stations are also detected. In step 1006, the determination of the DwPCH signals found in step 1005 is performed. In step 1006, the power of each of the DwPCH signals found in step 1005 is compared with the threshold value 2. Threshold 2 is basically the minimum power required to perform all procedures. In other words, the signals that do not exceed the threshold value 2 can be said to have a very high degree of distortion. Therefore, these signals are considered to be wrong data. Therefore, the signals are discarded without being treated as a measurement value. In step 1006, only signals exceeding the threshold 2 are passed, and the signals are input in step 1007, and in step 1007, the time difference from the reference DwPCH signal is calculated, and the process is completed.

11 is a flowchart when a base station receives a signal from a terminal.

In step 1101 of FIG. 11, the base station enters a UE location estimation process. The base station determines whether the UE measures the time difference of arrival of the DwPCH signals of each base station among the signals of the UEs currently transmitted to the base station in step 1102. If it is determined in step 1102 that measurement data for UE location estimation has been transmitted from the UE, the process moves to step 1103. If there is no information transmitted from the UE as a result of step 1102, the process ends with step 1105. In step 1103, the base station detects data measured by the UE and transmitted to the base station, and the base station calculates the location of the UE with the information. The result is stored by the base station and ends at step 1105.

As described above, the present invention has an advantage of effectively identifying the location of the UE.

Claims (6)

A method for estimating the position of a terminal in a mobile communication system, Receiving a pilot channel signal from a serving base station and a plurality of neighboring base stations of the terminal during a specific downlink signal period at the terminal, When the power of the pilot channel signal received from the serving base station is greater than a preset threshold, the pilot signal received from the serving base station is removed from the pilot channel signals received from the serving base station and a plurality of neighboring base stations to remove the plurality of neighbor base stations. Outputs a pilot channel signal received from If the power of the pilot channel signal received from the serving base station is less than a predetermined threshold value, and outputs a pilot channel signal received from the serving base station and the plurality of neighboring base stations, After decoding the output pilot channel signals, calculating a time difference between pilot channel signals having a power greater than a predetermined minimum power among the decoded pilot channel signals, and estimating a position including a time difference between the pilot channel signals. Transferring information to at least one of the serving base station and the plurality of neighbor base stations; And estimating the position of the terminal by using the position estimation information at the base station receiving the position measurement information. The method of claim 1, And the specific downlink signal interval is a pilot channel signal transmission slot. In the terminal device for estimating the position of the terminal, A receiver for receiving pilot channel signals from a serving base station and a plurality of neighboring base stations of the terminal during a specific downlink signal period; A determiner that compares the power of the pilot channel signal received from the serving base station and a preset threshold to determine whether to remove the pilot signal received from the serving base station from the pilot channel signals received from the serving base station and a plurality of neighboring base stations; , Wherein the determiner removes the pilot signal received from the serving base station from the pilot channel signals received from the serving base station and a plurality of adjacent base stations as the power of the pilot channel signal received from the serving base station is greater than a preset threshold. A determination unit for removing pilot signals received from the serving base station from the pilot channel signals received from the serving base station and the plurality of neighbor base stations and outputting pilot channel signals received from the plurality of neighbor base stations; Receiving at least one of the pilot channel signals received from the plurality of neighbor base stations and the pilot channel signals received from the serving base station and the plurality of neighbor base stations, and decoding the transmitted pilot channel signals; After calculating a time difference between pilot channel signals having a power greater than a predetermined minimum power among the decoded pilot channel signals, the pilot channel for transferring to at least one of the serving base station and the plurality of neighbor base stations And a time difference calculator for outputting position estimation information including time difference between signals. The method of claim 3, wherein The specific downlink signal interval is a pilot channel signal transmission slot. The method of claim 3, wherein When the pilot signal received from the serving base station is removed from the pilot channel signals received from the serving base station and the plurality of neighbor base stations according to the determination result, the removing unit removes the pilot channel signals received from the serving base station and the plurality of neighbor base stations. Pass it on, A switch for transmitting pilot channel signals received from the serving base station and the plurality of neighbor base stations to the time difference calculator when the pilot signals received from the serving base station are not removed from the pilot channel signals received from the serving base station and the plurality of neighbor base stations. Terminal device further comprising. delete

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