CN100591158C - A Method of Positioning Enhancement Using Beamforming in LCR-TDD System - Google Patents

Abstract

In the method of using beamforming to implement positioning enhancement in the LCR-TDD system, the SRNC sends a message to control the UE to enter the CELL_PCH state of the connected mode; the SRNC sends a public measurement initialization request message to Node B; Node B then sends back a public measurement initialization response message, and starts at the same time AOA measurement on RACH channel; RNC controls UE to perform OTDOA measurement on active set cells and neighboring cells by sending measurement control message; according to the requirements of the received measurement control message, return the OTDOA measurement result in the measurement report message to SRNC; RNC receives the RACH channel data frame or RACH/CPCH[FDD] channel data frame sent by the user plane of the Iub/Iur interface, extracts the UE identifier from the message, and if the ID points to the UE being positioned, extracts the RACH_AOA measurement result and RACH_AOA accuracy estimation domain. The present invention implements AOA measurement through beamforming and completes the positioning function in combination with OTDOA/Cell-ID, so as not to occupy dedicated wireless resources and reduce the necessary additional signaling overhead for UE transition state.

Description

A Method of Positioning Enhancement Using Beamforming in LCR-TDD System

technical field

The present invention relates to the third-generation mobile communication system, more specifically to a method for implementing positioning enhancement using beamforming in a 1.28Mcps low chip rate Time Division Duplex Code Division Multiple Access (LCR-TDD CDMA) system.

Background technique

The LCR-TDD system is a low chip rate time division duplex code division multiple access (LCR-TDDCDMA) system, and 3GPP has formulated corresponding technical specifications for the LCR-TDD code division multiple access. The LCR-TDD CDMA system will be able to be installed at Node B using Smart Antennas (SA). A smart antenna (SA) is an antenna array composed of multiple low-gain antenna elements. It uses digital signal processing technology to implement beamforming on multiple different users to generate multiple different spatial beams. The maximum direction of each beam automatically aligns Align the respective users, and align the zero receiving direction with the interference direction to suppress co-channel interference, multiple access interference and multipath fading, so as to achieve the purpose of significantly improving the signal-to-interference ratio and enhancing the system capacity.

Since the smart antenna uses an array antenna with a different number of array elements in a certain spatial position, the same radio signal arrives at each array element with different wave path differences, and signals in different directions produce different array responses after beamforming (Beamforming) of the array antenna. The angle of arrival (AOA) of the wave can be estimated. The smart antenna receiving system can adopt different algorithms, which can be implemented in radio frequency, intermediate frequency or baseband respectively, so as to distinguish signals from different directions, thereby reducing interference and improving system performance.

Fig. 1 is a structural diagram of implementing location services defined by the 3GPP standardization organization, which includes RNC102 and 103, location measurement unit (LMU) associated with Node B104 and 105, independent location measurement unit 107 (Stand-alone LMU), independent service Mobile positioning center 108 (SAS), user equipment 106 (UE) and core network 101 (CN), each entity communicates through interfaces 111, 113, 112, 110, 109 (Iu, Iub, Iur, Iupc, Uu). The SRNC 102 exchanges positioning service signaling with the CN through the Iu111 interface, and the SRNC is responsible for controlling UTRAN resources (Node B, LMU, SAS), user equipment (UE) and computing functions, thereby estimating the position of the UE and returning the positioning result to the CN.

In the current technical specification of 3GPP, three positioning technologies are defined, namely Cell-ID, Observed Time Difference of Arrival (OTDOA) and Assisted Global Positioning System (A-GPS). In addition, these three techniques can be combined with other available measurements to increase the accuracy of the positioning without significantly increasing the complexity of the system.

Therefore, the present invention proposes to add angle of arrival (AOA) measurement to OTDOA/Cell-ID positioning measurement in LCR-TDD code division multiple access system to improve positioning accuracy.

In the existing 3GPP protocol, as shown in FIG. 2 , the following briefly describes the signaling process of performing positioning in combination with OTDOA of AOA measurement in the Cell Dedicated Channel (CELL_DCH) state of the Radio Resource Control (RRC) connected mode. It should be noted that the modes of the UE are divided into idle (IDLE) mode and RRC connected mode, wherein the RRC connected mode includes four states of CELL_DCH, CELL_FACH, CELL_PCH, and URA_PCH. It is worth noting that the existing 3GPP specification defines that the UE must work in the CELL_DCH state of the RRC connection mode. In order to clearly describe the content specified in the existing specification, the present invention only shows the signaling related to the UE positioning operation in the figure, which mainly includes the following steps:

First, the core network (CN) sends a location control report to the UE to the SRNC, and the SRNC then analyzes the location request and selects an appropriate location method according to the UE's capabilities (step 201); The cell performs OTDOA measurement, wherein the OTDOA measurement is completed in the CELL_DCH state of the RRC connection mode (step 202); the UE can return the measurement result of OTDOA to the SRNC (step 203); if the SRNC cannot obtain enough OTDOA measurement information, or consider additional Under the situation that measurement has advantage for improving precision, SRNC also can request Node B to measure the AOA (step 204) of serving cell; If SRNC requests Node B to carry out AOA measurement (only to LCR-TDD system), so Node B reports AOA value to SRNC (step 205); SRNC is able to perform position calculations combining OTDOA and AOA information. In addition, the geographic information coordinate system adopted may also be converted according to customer application requirements. Position estimation includes position information, position accuracy estimation, measurement time, etc. If the core network includes the entity SAS, the SAS can perform the positioning calculation function and send the result to the SRNC (step 206); finally, the SRNC reports the positioning estimation to the core network, and can also report the measurement method or positioning method list used for the positioning estimation according to the requirements ( Step 207).

In the existing 3GPP protocol, the AOA measurement mechanism has the following characteristics:

1) The AOA measurement can only be obtained by measuring the dedicated channel in the CELL_DCH state of the RRC connection mode, that is, in order to complete the AOA measurement, the UE must be in the CELL_DCH state;

2) Assuming that the core network initiates a positioning request for a UE in an idle (IDLE) state, the UE must first establish an RRC connection and enter the CELL_DCH state, which means that dedicated radio resources, such as spreading codes, must be allocated to the UE;

3) Assuming that the core network initiates a positioning request for a UE in the CELL_FACH, CELL_PCH, and URA_PCH states, the UE must first perform necessary signaling to transfer to the CELL_DCH state, which means that dedicated radio resources must be allocated for the UE, such as extension frequency code, etc.;

Based on the above analysis, for UEs that are not in the RRC connection mode CELL_DCH state, the current LCR-TDD system has the following defects in the AOA measurement mechanism:

1) Only in order to complete the positioning operation, such as measuring AOA, it is necessary to allocate dedicated radio resources for the user and transfer the UE to the CELL_DCH state, which is not conducive to the effective use of the precious channel code resources of the LCR-TDD system, because the channel of the LCR-TDD system Code resources are limited;

2) If the UE is in the idle (IDLE) state and the RRC connection mode CELL_FACH, CELL_PCH, and URA_PCH state, necessary control signaling is required to make the UE transition to the CELL_DCH state in order to perform related measurements, such as measuring AOA, which is obviously for resources a consumption.

Contents of the invention

The purpose of the present invention is to provide a method for improving positioning by combining OTDOA/Cell-ID positioning technology with AOA measurement in the LCR-TDD system configured with beamforming, which can complete the measurement work of positioning with relatively low resource consumption , to optimize system resource management.

In order to achieve the above purpose, a method for implementing positioning enhancement using beamforming in an LCR-TDD system includes steps:

(a) SRNC sends a message to control the UE to enter the CELL_PCH state of the connection mode;

(b) SRNC sends a public measurement initialization request message to Node B;

(c) Node B then sends back the public measurement initialization response message, and at the same time starts the AOA measurement of the RACH channel;

(d) The RNC controls the UE to perform OTDOA measurement on the active set cell and the neighboring cell by sending a measurement control message;

(e) According to the requirements of the received measurement control message, return the measurement result of OTDOA to SRNC in the measurement report message;

(f) RNC receives the RACH channel data frame or RACH/CPCH[FDD] channel data frame sent by the user plane of the Iub/Iur interface, extracts the ID of the UE from the message, and extracts the RACH_AOA measurement result if the ID points to the UE being positioned and RACH_AOA accuracy estimation domain.

The present invention proposes to implement AOA measurement through beamforming in the RRC connection mode CELL_FACH state, and complete the positioning function in combination with OTDOA/Cell-ID, so as to achieve the purpose of not occupying dedicated wireless resources and reducing the necessary additional information for UE transition state. order overhead.

Description of drawings

Figure 1 is a structural diagram of implementing positioning services in 3GPP;

Figure 2 is the OTDOA positioning signaling flow combined with AOA measurement in the existing specification;

Fig. 3 is the OTDOA positioning improvement signaling process (IDLE) proposed in conjunction with the AOA measurement proposed by the present invention;

Fig. 4 is the OTDOA location improvement signaling process (CELL_PCH/URA_PCH) that the present invention proposes in conjunction with AOA measurement;

Fig. 5 is the structure of Iub user plane common channel RACH data frame;

Fig. 6 is the structure of the Iur user plane common channel RACH/CPCH [FDD] data frame.

Detailed ways

The present invention is aimed at the defect that consumes dedicated resources in the OTDOA/Cell ID that combines AOA measurement in the existing 3GPP specification and implements the positioning scheme, proposes the following a kind of time division duplex code division multiple access (LCR) at a low chip rate of 1.28Mcps -Using beamforming to measure AOA in the TDD CDMA) system to implement the method for positioning enhancement, the key technical points of its invention are as follows:

(1) Complete the relevant positioning measurement operation in the CELL_FACH state of the RRC connection mode instead of the CELL_DCH state;

(2) The measurement type needs to be included in the Common Measurement Initiation Request (Common Measurement Initiation Request) message and the Common Measurement Initiation Response (Common Measurement Initiation Response) message of the Iub interface protocol between RNC and Node B and the interface protocol Iur between RNCs respectively A Random Access Angle of Arrival (RACH_AOA) field is added to the information element (IE) to control Node B to implement random access channel angle of arrival measurement;

(3) Node B measures AOA by implementing beamforming on the uplink random access channel (RACH) sent by the UE;

(4) By extending the data field of the Iub/Iur interface user plane data frame, the AOA measurement result measured by the Node B is transmitted to the RNC.

Figure 5 shows the Iub user plane RACH channel data frame structure. In order to support the reporting of the RACH AOA measurement result of the present invention, the RACH data frame is extended, and specifically two fields are added: AOA measurement result 501 and AOA accuracy 502 . At the same time, indicate to the RNC whether the above two fields of AOA measurement result and AOA accuracy are available through a certain bit of the New Information Element Flags (New IE flags) field.

Figure 6 shows the Iur user plane RACH/CPCH[FDD] channel data frame structure. In order to support the reporting of AOA measurement results, the RACH/CPCH[FDD] data frame needs to be extended, specifically adding two fields: AOA measurement result 601 and AOA accuracy 602 . At the same time, indicate to the RNC whether the above two fields of AOA measurement result and AOA accuracy are available through a certain bit of the New Information Element Flags (New IE flags) field.

SRNC according to the present invention receives the RACH channel data frame (or RACH/CPCH[FDD] channel data frame) that Iub/Iur interface user plane sends, extracts the identification of UE from message, if this ID points to the UE being positioned, extracts The corresponding AOA measurement results and AOA accuracy estimation fields are used to perform position calculations in combination with methods such as OTDOA or Cell ID, and send the results of position estimation to the core network (CN).

Describe the present invention below in conjunction with several examples.

Referring to FIG. 3 to describe the first embodiment of the present invention, that is, the core network (CN) initiates a signaling process for positioning a UE in the IDLE state:

First, when the UE is in an idle state, the core network (CN) sends a paging message (Paging) to the SRNC (step 301); after receiving the paging message (Paging), the SRNC sends the paging type according to the service area registered by the UE 1 (Paging Type 1) message to page the UE (step 302); after the UE receives the Paging Type 1 message, it implements the RRC connection between the UE and the SRNC by sending the RRC Connection Request (RRC ConnectionRequest) message, so as to start from the idle state Transfer to the RRC connection state (step 303); Then, the SRNC sends back the RRC connection setup (RRCConnection Setup) message to confirm the RRC connection request of the UE, and after the UE has received the RRC connection setup, the UE enters the CELL_FACH state of the RRC connection mode, in In this state, the UE does not allocate dedicated resources, but only has a signaling connection with RRC (step 304); the UE confirms the signaling connection of RRC by sending back an RRC Connection Setup Complete (RRC Connection Setup Complete) message to the SRNC and reports this to the SRNC The capability information possessed by the UE, including the capability of positioning etc. (step 305); then, the UE sends an Initial Direct Transfer (Initial Direct Transfer) message to the SRNC to respond to paging (306); after the SRNC receives the initial direct transfer message , by sending an initial UE message (Initial UE Message) to respond to the paging of the CN (307); the CN then sends a Location Reporting Control (Location Reporting Control) message to the SRNC to request the location information of the UE. SRNC receives the location report control (Location Reporting Control) message that CN sends, combines UE capability and the accuracy requirement of location, selects the appropriate location method, for example SRNC selects the OTDOA location estimation method (step 308) that combines AOA measurement; Because SRNC The OTDOA positioning estimation method combined with AOA measurement is selected, so the SRNC sends a Common Measurement Initiation Request (Common Measurement Initiation Request) message to the Node B, which includes in the Common Measurement Initiation Request (Common Measurement Initiation Request) message measurement type information element (IE) Randomly access the angle of arrival (RACH_AOA) field to configure the NodeB to start the AOA measurement (step 309) of the access channel; the NodeB then sends back a Common Measurement Initiation Response (Common Measurement Initiation Response) message, and simultaneously starts the AOA measurement of the RACH channel; In addition, the Node B reports the measurement result to the SRNC (step 310) through the RACH channel data frame (or RACH/CPCH[FDD] channel data frame) of the Iub/Iur interface user plane; then, the SRNC sends a measurement control (MeasurementControl) message To control the UE to perform OTDOA measurement on the active set cells and neighboring cells. It is worth noting that the OTDOA measurement in the present invention is completed in the RRC connection mode CELL_FACH state (step 311); the UE returns the OTDOA in the measurement report (Measurement Report) message according to the requirements of the received Measurement Control (Measurement Control) message The measurement result to SRNC; This message is sent to SRNC through the Iub/Iur interface user plane through Node B on the random access channel, and simultaneously carries the AOA information of RACH channel (step 312); SRNC receives the Iub/Iur interface user plane transmission The incoming RACH channel data frame (or RACH/CPCH[FDD] channel data frame), extracts the ID of the UE from the message, and if the ID points to the UE being positioned, extracts the RACH_AOA measurement result and the RACH_AOA accuracy estimation field. The SRNC performs position calculation for locating the UE based on OTDOA combined with AOA information. In addition, the calculation can also convert the geographic information coordinate system adopted according to the customer's application requirements, and the positioning estimation includes position information, position accuracy estimation, and measurement time. If the core network includes the entity SAS, the SAS can also perform the positioning calculation function and send the result to the SRNC (step 313); the SRNC reports the positioning estimation result to the core network, and can also report the measurement method or positioning method list used for the positioning estimation according to the requirements ( Step 314). At last, SRNC sends RRC connection release message to UE, and informs UE to release RRC connection related resources (step 315); UE sends back RRC connection release completion message to SRNC after receiving RRC connection release message, gets back to idle mode state (step 316 again) ).

Referring to FIG. 4 to describe the first embodiment of the present invention, that is, the core network (CN) initiates a signaling process for positioning a UE in the CELL_PCH/URA_PCH state:

First, after receiving the Location Reporting Control (Location Reporting Control) message sent by the CN, the SRNC selects a suitable location method in combination with the stored UE capability and location accuracy requirements, for example, the SRNC selects an OTDOA location estimation method combined with AOA measurement (401); When UE is in RRC connection mode CELL_PCH state or URA_PCH state, SRNC sends the paging message of Paging Type 1 type to page UE; After UE receives paging message, UE transfers to the CELL_FACH state of RRC connection mode (step 402) ; The UE then sends a cell update (CELL UPDATE) message to the SRNC to respond to the paging message, and the SRNC can obtain the cell information (step 403) where the UE is located; then, the SRNC sends back the CELL UPDATE CONFIRM message to confirm that the cell update sent by the UE has been received message (step 404); because the SRNC has selected the OTDOA location estimation method in conjunction with the AOA measurement, so the SRNC sends a common measurement initialization request (Common MeasurementInitiation Request) message to the Node B, wherein the common measurement initialization request (CommonMeasurement Initiation Request) message measurement type The information element (IE) includes a random access angle of arrival (RACH_AOA) field to configure the Node B to start the AOA measurement of the access channel (step 405); the Node B then sends back a Common Measurement Initiation Response (CommonMeasurement Initiation Response) message, and simultaneously starts To the AOA measurement of RACH channel; In addition, NodeB reports measurement result to SRNC (step 406) by the RACH channel data frame (or RACH/CPCH[FDD] channel data frame) of Iub/Iur interface user plane; Then, SRNC sends by sending The Measurement Control (Measurement Control) message is used to control the UE to perform OTDOA measurements on the active set cells and neighboring cells. It is worth noting that the OTDOA measurement in the present invention is completed in the RRC connection mode CELL_FACH state (step 407); the UE returns the OTDOA in the measurement report (Measurement Report) message according to the requirements of the received Measurement Control (Measurement Control) message The measurement result to SRNC; This message is sent to SRNC through the Iub/Iur interface user plane through Node B on the random access channel, and simultaneously carries the AOA information of RACH channel (step 408); SRNC receives the Iub/Iur interface user plane transmission The incoming RACH channel data frame (or RACH/CPCH[FDD] channel data frame), extracts the ID of the UE from the message, and if the ID points to the UE being positioned, extracts the RACH_AOA measurement result and the RACH_AOA accuracy estimation field. The SRNC performs position calculations for positioning UEs based on OTDOA combined with AOA measurements. In addition, the calculation can also convert the geographic information coordinate system adopted according to the customer's application requirements, and the positioning estimation includes position information, position accuracy estimation, and measurement time. If the core network includes the entity SAS, the SAS can also perform the positioning calculation function and send the result to the SRNC (step 409); the SRNC reports the positioning estimation result to the core network, and can also report the measurement method or positioning method list used for the positioning estimation according to the requirements ( Step 410); Finally, the SRNC sends a physical channel reconfiguration message to the UE, and the RRC connection state of the control UE will return to the CELL_PCH/URA_PCH state (step 411); after the UE receives the physical channel reconfiguration message, the physical channel reconfiguration is returned and completed message to SRNC, UE then re-enters CELL_PCH/URA_PCH state (step 412).

Claims (10)

1. plant and in the LCR-TDD system, utilize beam shaping to implement the method that the location strengthens, comprise step:

(a) SRNC sends the CELL_PCH state that message control UE enters connection mode;

(b) SRNC sends public-measurement initialization request message to Node B;

(c) Node B loopback public-measurement initialization answer message subsequently begins the AOA of RACH channel is measured simultaneously;

(d) RNC controls UE to Active Set sub-district and neighbor cell execution OTDOA measurement by sending the measurement control messages;

(e) according to the requirement of the measurement control messages of being received, the measurement result of returning OTDOA in measurement report message is to SRNC;

(f) RNC receives RACH channel data frame or the RACH/CPCH[FDD that the Iub/Iur interface user plane is sent] channel data frame, from message, extract the sign of UE, if this ID points to the UE that is locating, extract RACH_AOA measurement result and RACH_AOA precision estimation domain.

2. by the described method of claim 1, it is characterized in that when UE is in idle condition that the message that described RNC transmission control UE enters the CELL_PCH state of connection mode comprises: message is set up in the RRC connection.

3. by the described method of claim 1, it is characterized in that when UE is in RRC connection mode CELL_PCH state or URA_PCH state the message that described RNC transmission control UE enters the CELL_PCH state of connection mode comprises: the beep-page message of Paging Type 1 type.

4. by the described method of claim 1, it is characterized in that comprising in the described public-measurement initialization request message and insert angle of arrival RACH_AOA field at random.

5. by the described method of claim 1, it is characterized in that described step (c) also comprises: NodeB is by the RACH channel data or the RACH/CPCH/[FDD of Iub/Iur interface user plane] channel data frame gives SRNC with measurement report.

6. by claim 4 or 5 described methods, it is characterized in that signaling is replied in the public-measurement initialization request of Iub/Iur interface protocol and public-measurement initialization increases a measurement type RACH_AOA respectively.

7. by the described method of claim 5, it is characterized in that, by the data field of Iub/Iur interface user plane Frame is expanded, so that the measured AOA measurement result of Node B is sent to RNC.

8. by the described method of claim 5, it is characterized in that Node B is to the measurement result of RACH channel AOA, by Iub user plane common signal channel RACH Frame and Iur user plane common signal channel RACH/CPCH[FDD] Frame report SRNC.

9. by the described method of claim 7, it is characterized in that, Iub user plane common signal channel RACH Frame is expanded corresponding territory, increased by two territories of AOA measurement result and AOA precision, and certain bit by the new information element mark domain indicates above-mentioned AOA measurement result and two territories of AOA precision whether available to RNC.

10. by the described method of claim 1, it is characterized in that, Iur user plane common signal channel RACH/CPCH[FDD] Frame expands corresponding territory, increased by two territories of AOA measurement result and AOA precision, and certain bit by the new information element sign indicates above-mentioned AOA measurement result and two territories of AOA precision whether available to RNC.

Images