CN1877356B - A Positioning Method Using Loopback Time - Google Patents

Abstract

The invention discloses a positioning method utilizing the loopback time, which comprises the following steps: Step A. According to the quantization unit of the loopback time set in sections, the base station converts the measured value of the loopback time into a reported value of the loopback time, and converts the reported value Report to the radio network controller; Step B. The radio network controller locates the terminal according to the measurement result reported by the base station. The positioning method using the loopback time of the present invention keeps the quantization unit of the RTT measurement value of the short-distance section unchanged while keeping the byte length reported by the RTT constant, and supports a wide coverage of the RTT in a cell radius of more than 68 kilometers related positioning.

Description

A Positioning Method Using Loopback Time

technical field

The invention relates to positioning technology, in particular to a positioning method using loopback time.

Background technique

The ^3rd Generation Partnership Project (3GPP) defines three positioning methods, namely cell identification (Cell ID), observed time difference of arrival (Observed Time Difference Of Arrival, OTDOA) and Assisted Global Positioning System (Assisted GPS). Global Positioning Systems, A-GPS).

Among them, both OTDOA and A-GPS put forward higher requirements on the network or mobile terminal. The former increases the cost of the network, and the latter increases the cost of the terminal. At the same time, A-GPS is also restricted by the environment of the terminal (UE). The positioning method of directly taking the Cell ID at the center of the cell is the easiest to implement, but the accuracy is also the worst. Therefore, the protocol also proposes an enhanced cell ID (Cell ID) positioning method, that is, Cell ID plus round trip time (Round Trip) Time, RTT) positioning technology to locate the terminal, using the round-trip time length of the signal propagation between the base station and the mobile phone, the distance between the terminal and the base station can be determined.

3GPP defines the loopback time as: RTT=T _RX -T _TX . Among them, T _TX is the start sending time of the downlink dedicated physical channel (Dedicated Physical Channel, DPCH) frame sent to the terminal, and the reference point is the transmitting antenna port; T _RX is the corresponding uplink dedicated physical channel/dedicated physical channel/dedicated frame from the terminal. At the start receiving moment of a physical data channel (Dedicated Physical Control Channel/Dedicated PhysicalData Channel, DPCCH/DPDCH) frame, the reference point is the receiving antenna port.

In theory, RTT is the time interval between when the base station (Node B) sends a downlink signal to the terminal and when the base station receives the uplink signal sent from the terminal. Since the terminal has a time difference Rx-Tx between receiving the downlink signal from the base station and sending the uplink signal to the base station, in the process of actually measuring RTT by the base station, the RTT measurement value includes the time difference Rx-Tx of the terminal. Therefore, in practice In the operation of calculating the circumference radius, the radio network controller (RNC) will subtract the time difference Rx-Tx of the terminal during signal transmission and reception after obtaining the RTT measurement value reported by the base station, so as to achieve more accurate positioning. That is, the specific location of the base station (antenna) and the direction of the sector are obtained according to the cell ID (Cell ID). Therefore, a circle (omnidirectional antenna) or a circular arc (combined with the sector pointing results of a sector cell) is determined with the specific location of the base station as the center and the distance from the terminal to the base station as the radius to realize terminal positioning.

In the 3GPP 25.214 protocol, since there is a certain range of time difference (T ₀ ±148chips) between the transmitting and receiving moments of the terminal, where T ₀ =1024chips, that is, 876~1172chips. The bit width of the RTT reported value is 15 bits, and the quantization unit is 1/16chips. The range of the RTT reported value is 0 to 2 ¹⁵ -1, that is, 0 to 32767. There is a corresponding relationship between the RTT reported value and the RTT measured value. The corresponding relationship is It is established according to the RTT reported value, the quantification unit of the RTT measured value, and the minimum sending and receiving time difference of the terminal, specifically:

(RTT _R -1)×Step+876≤RTT _M <RTT _R ×Step+876

Among them, RTT _R is the reported value, RTT _M is the measured value, Step is the quantization unit, and 876 is the fixed value used when mapping from the RTT measured value to the RTT reported value. In fact, the minimum value of the terminal sending and receiving time difference is taken. Therefore, Call 876 the minimum sending and receiving time difference T _min . When the quantization unit of the RTT measurement value is 1/16chips, the mapping relationship between the RTT reported value and the RTT measurement value is:

(RTT _R -1)×1/16+876≤RTT _M <RTT _R ×1/16+876

The unit in the RTT reporting mapping table is a chip (chip), and the maximum range that the RTT measurement value can represent is 2 ¹⁵ × 1/16 + 876 = 2924chips. Considering the time difference T ₀ ±148chips between the terminal’s transmission and reception moments, When the value of the sending and receiving time difference Rx-Tx is the maximum sending and receiving time difference T _max = 1172chips, according to the formula (RTT-(R _X -T _X ))/2, the maximum cell radius that can be expressed is (2924-1172)/2 =876 chips, 1 chip is equivalent to 78.125 meters, and the corresponding cell radius distance is 876×78.125=68 kilometers.

However, in the case of wide coverage, the radius of the cell may be greater than 68 kilometers, reaching hundreds of kilometers. At this time, if the quantization unit is 1/16chips, the RTT report value with a bit width of 15 bits will not be able to support the distance (greater than 68 kilometers) ) RTT-related positioning functions. For example, at a cell radius of 120 kilometers, the RTT measurement value corresponding to the transmission and reception time difference Rx-Tx value of 1024 is 120×1000/78.125×2+1024=4096chips, which exceeds the maximum range of 2924 that can be represented by the RTT measurement value, so it is limited application.

Contents of the invention

The purpose of the present invention is to provide a positioning method using loopback time, which is applicable to wide coverage scenarios with a cell radius of more than 68 kilometers without changing the byte length reported by RTT.

The positioning method utilizing the loopback time of the present invention may comprise the following steps:

Step A. The base station converts the loopback time measurement result into a loopback time report value according to the loopback time quantization unit set in sections, and reports the reported value to the radio network controller;

Step B. The radio network controller locates the terminal according to the measurement result of the loopback time reported by the base station.

Wherein, the numerical value of the quantization unit of the loopback time increases as the distance increases.

Wherein, the step B specifically includes the following steps:

The terminal reports the Rx-Tx measurement result of the sending and receiving time difference to the radio network controller, and the radio network controller locates the terminal according to the Rx-Tx measurement result and the loopback time measurement result reported by the base station.

The following steps may be further included before the step B:

The radio network controller may initiate the measurement of the sending and receiving time difference Rx-Tx to the terminal.

In the step A, the quantization unit of the loopback time is set to 0.0625chips within the range of 8.5 kilometers.

The bit width of the loopback time report value is 15 bits.

In the step A, the quantization unit may be set according to the actual cell coverage.

Wherein, the process of setting the quantization unit in the step A may include the following steps:

According to the actual cell coverage, the corresponding maximum value of the loopback time is obtained;

Within the range from zero to the maximum value of the round-trip time, the quantization unit of the measured value of the round-trip time may be set in increments as the distance increases.

The segment settings may be equal-spaced or non-equal-spaced segmented settings.

The quantization unit of the segment may be one or a combination of an arithmetic sequence and a geometric sequence.

The beneficial effects of the present invention are: according to the positioning method utilizing the loopback time of the present invention, the quantization unit of the RTT measurement value is set in segments, and the short-distance segment RTT measurement value is maintained under the condition that the byte length reported by the RTT remains unchanged. The unit of quantification remains unchanged, and at the same time, it can support RTT-related positioning functions when the cell radius is more than 68 kilometers and the coverage is wide.

Description of drawings

FIG. 1 is a flow chart of the positioning method using loopback time according to the present invention.

Detailed ways

The positioning method using the loopback time of the present invention will be described in detail below with reference to FIG. 1 .

In the 3GPP 25.133 protocol, it is defined that the reporting range of RTT is 0 to 32767, the bit width of the RTT reported value is 15 bits, and the quantization unit is 0.0625chips. When the quantization unit of the RTT measurement value in the distance range remains unchanged, as the distance increases, the value of the quantization unit is increased, and the quantization unit of the RTT measurement value is set in sections to meet the application scenarios under wide coverage.

As shown in Table 1, it is the RTT reporting mapping table used in the Cell ID+RTT positioning process of the present invention. The RTT reporting mapping table includes three items of RTT reporting value, RTT measurement value and unit. Wherein, the RTT reported value ranges from 0 to 32767, and the RTT reported values are arranged in the first column of Table 1 in an increasing manner. There is a corresponding relationship between the RTT reported value and the RTT measured value in the same row. The corresponding relationship is established based on the RTT reported value, the quantification unit of the RTT measured value, and the minimum sending and receiving time difference, specifically:

(RTT _R -1)×Step+876≤RTT _M <RTT _R ×Step+876

As shown in Table 1, keep the bit width (15 bits) of the RTT reported value unchanged, and keep the quantization unit (0.0625chips) of the RTT measurement value in the close range unchanged, and increase the RTT measurement value as the distance increases. Quantification unit value: the reported value of the first RTT is 0~8191, and the quantization unit is 0.0625chips; the reported value of the second RTT is 8192~16383, and the quantification unit is 0.125chips; the reported value of the third RTT is 16384 ~24575, the quantization unit is 0.25chips; the reported value of the RTT in the fourth segment is 24576~32767, and the quantization unit is 0.5chips.

After such processing, the RTT measurement value corresponding to the maximum RTT reported value of 32767 is 8556, and the maximum cell radius that can be represented reaches 3692chips ((8556-1024-148)/2=3692), corresponding to 288 kilometers (3692×78.125 m = 288.4375 kilometers).

reported value Measurements unit RT_TIME_0000 Round trip time＜876.0000 chip RT_TIME_0001 876.0000≤Round trip time＜876.0625 chip RT_TIME_0002 876.0625≤Round trip time＜876.1250 chip RT_TIME_0003 876.1250≤Round trip time＜876.1875 chip ... ... ... RT_TIME_8189 1387.7500≤Round trip time＜1387.8125 chip RT_TIME_8190 1387.8125≤Round trip time＜1387.8750 chip

reported value Measurements unit RT_TIME_8191 1387.8750≤Round trip time＜1388.0000 chip RT_TIME_8192 1388.0000≤Round trip time＜1388.1250 chip RT_TIME_8193 1388.1250≤Round trip time＜1388.2500 chip RT_TIME_8194 1388.2500≤Round trip time＜1388.3750 chip ... ... ... RT_TIME_16381 2411.6250≤Round trip time＜2411.7500 chip RT_TIME_16382 2411.7500≤Round trip time＜2411.8750 chip RT_TIME_16383 2411.8750≤Round trip time＜2412.0000 chip RT_TIME_16384 2412.0000≤Round trip time＜2412.2500 chip RT_TIME_16385 2412.2500≤Round trip time＜2412.5000 chip RT_TIME_16386 2412.5000≤Round trip time＜2412.7500 chip ... ... ... RT_TIME_24573 4460.2500≤Round trip time＜4460.5000 chip RT_TIME_24574 4460.5000≤Round trip time＜4460.7500 chip RT_TIME_24575 4460.7500≤Round trip time＜4460.0000 chip RT_TIME_24576 4460.0000≤Round trip time＜4460.5000 chip RT_TIME_24577 4460.5000≤Round trip time＜4470.0000 chip RT_TIME_24578 4470.0000≤Round trip time＜4470.5000 chip ... ... ... RT_TIME_32764 8554.0000≤Round trip time＜8554.5000 chip RT_TIME_32765 8554.5000≤Round trip time＜8555.0000 chip RT_TIME_32766 8555.0000≤Round trip time＜8555.5000 chip

reported value Measurements unit RT_TIME_32767 8555.5000≤Round trip time chip

Table 1

Specifically, the positioning process is as follows: first, the radio network controller (RNC) initiates RTT measurement to the base station (NodeB), and initiates the measurement of the sending and receiving time difference Rx-Tx to the terminal (UE); then, the terminal performs the Rx-Tx measurement The result is reported to the radio network controller, and the base station also reports the RTT measurement result to the radio network controller; finally, the radio network controller uses the formula (RTT-(R _x -T _x ) according to the measurement results reported by the terminal and the base station respectively )/2 to calculate the distance between the terminal and the base station (antenna). According to the cell ID (Cell ID), the specific location of the base station and the direction of the sector are obtained. With the specific location of the base station as the center and the distance from the terminal to the base station as the radius, a circle (omnidirectional antenna) or a circular arc (combined with the sector of the sector cell) is determined. area pointing to the result), to realize the positioning of the terminal.

Next, referring to FIG. 1 , the positioning method using the loopback time of the present invention will be described in detail.

Under the condition of not changing the byte length of the existing RTT report value, the positioning method utilizing the loopback time of the present invention comprises the following steps:

Step 1) Set the quantization unit of RTT in the base station and the radio network controller in advance, the numerical value of the quantization unit increases with the increase of the distance, and in the base station and the radio network controller, the quantization unit of the RTT is carried out Segment settings are the same;

Step 2) The radio network controller initiates RTT measurement to the base station, and initiates the measurement of the sending and receiving time difference Rx-Tx to the terminal;

Step 3) The terminal reports the measurement result of Rx-Tx to the radio network controller, and the base station also reports the measurement result of RTT to the radio network controller;

Wherein: in step 3), the base station converts the RTT measurement value into an RTT reporting value according to the RTT quantization unit set in step 1), and reports it to the radio network controller.

Step 4) The radio network controller locates the terminal according to the received terminal and the measurement result reported by the base station.

Wherein, in step 4), the radio network controller obtains the measurement result of RTT according to the RTT quantization unit mapping set in step 1), and combines the measurement result reported by the terminal through the formula (RTT-(R _x -T _x ))/ 2 Calculate the distance between the terminal and the base station (antenna), so as to realize the positioning of the terminal.

Wherein, in step 4), the wireless network controller locates the terminal according to the calculated distance between the terminal and the base station, which is a prior art, and will not be described in detail in the present invention.

Below in conjunction with Table 1, a specific example is used to illustrate the actual application of the positioning method utilizing the loopback time of the present invention:

First, without changing the existing RTT bit width, the base station maps the current RTT measurement value in the range of 4460.2500 to 4460.5000chips to the RTT report value 24573 according to its own saved Table 1, and reports the RTT report value 24573 to Wireless network controller. At this time, for the base station, the quantization unit is 0.25chips.

Secondly, the radio network controller receives the RTT report value (24573), and according to the mapping rule between the RTT report value and the RTT measurement value stored by itself (the mapping rule is the same as that stored in the base station, that is, Table 1), to obtain the RTT The RTT measurement value corresponding to the reported value 24573 is 4460.2500~4460.5000chips.

Again, the radio network controller completes the positioning of the terminal according to the method of the prior art according to the obtained RTT measurement value, the Rx-Tx value received from the terminal, and the base station (antenna) position and cell range determined by the Cell ID. In this way, positioning in a wide-coverage scenario where the terminal is 128 kilometers away from the base station (antenna) is realized.

In the above example, the calculated specific value (128 kilometers) between the terminal and the base station is related to the value of Rx-Tx: when Rx-Tx is T ₀ +148, the maximum cell radius that RTT can represent is 1644.125 chips ( (4460.25-1024-148)/2=1644.125), which corresponds to 128 kilometers (1644.125×78.125=128.447); when Rx-Tx takes T ₀ -148, the maximum cell radius that RTT can represent is 1792.125chips ((4460.25- 1024+148)/2=1792.125 chips, corresponding to 140 kilometers (1792.125×78.125=140.009 kilometers).

After this processing, the word length reported by the RTT remains unchanged, and the quantization unit of the RTT measurement value in the short-distance range (corresponding to the first segment of the RTT, with a cell radius of about 8.5 kilometers) remains unchanged, which does not affect the positioning accuracy performance. For locations farther away from the base station, use the RTT-related positioning method. Other factors (such as the long arc length caused by the fan-shaped opening angle) have already become the main factors affecting the positioning accuracy. At this time, the RTT quantization unit is appropriately reduced. Accuracy has little effect.

Above, the present invention only uses equidistant segmentation as a preferred segmentation method, and the quantization unit of segmentation is geometric sequence, but the present invention is not limited thereto, and geometric sequence, geometric sequence and the like can also be used Segmentation processing is carried out by means of combination of difference series or non-equidistance, corresponding to different quantization units of each segment. Generally, when the RTT measurement value is small, the quantization unit is small, and when the RTT measurement value is large, the quantization unit is large, but it can be set arbitrarily. To realize the present invention, it is only necessary to satisfy the principle that the quantization unit is small in the short-distance range and large in the long-distance range.

In addition, the quantization unit of the RTT measurement value can be set according to the actual cell coverage.

Specifically, the following steps are included:

Obtain the maximum value of the corresponding RTT measurement value according to the actual cell coverage;

According to the maximum value of the RTT measurement value, the quantization unit of the RTT measurement value is set segmentally. The specific segment setting process is as described above. As the distance increases, the numerical value of the quantization unit is increased, and the quantization unit of the RTT measurement value is set segment by segment, which will not be described in detail in the present invention.

For example, the actual cell coverage is 180 kilometers. At this time, the maximum value of the corresponding RTT measurement value is 4608 (180×1000/78.125×2=4608), calculated according to the minimum sending and receiving time difference Rx-Tx as T _min The value range of the RTT measurement value is 876-4608+876chips, and then the quantization unit of the RTT measurement value is set for the 876-4608+876chips segment.

In addition, the positioning method using the loopback time of the present invention is not limited to the Cell ID+RTT positioning technology to locate the terminal. In the observed time difference of arrival (OTDOA) positioning technology, the time difference of arrival (Time Difference of Arrival) measured by the terminal can also be used. Of Arrival, TDOA), combined with the RTT measurement value is converted into time distance of arrival (ToA), so as to locate the terminal. Among them, in the Observed Time Difference of Arrival (OTDOA) positioning technology, as mentioned above, the quantization unit of the RTT measurement value is set in segments to support the positioning function of the wide-coverage scene.

In summary, according to the positioning method using the loopback time of the present invention, the quantization unit of the RTT measurement value is set in sections to ensure that the byte length of the RTT reported value remains unchanged, and the quantification unit of the RTT measurement value in the short range is maintained No change, while being compatible with existing cell coverage scenarios, it realizes wide coverage scenarios with a cell radius of more than 68 kilometers.

The above description is to facilitate those of ordinary skill in the art to understand the present invention and describe the present invention in detail, but it is conceivable that other changes and modifications can be made without departing from the scope covered by the claims of the present invention. These changes All modifications and modifications are within the protection scope of the present invention.

Claims (9)

1. a localization method that utilizes the winding time is characterized in that, comprises the following steps:

Steps A. according to the winding time quantization unit of segmentation setting, the base station is converted to the winding time value of reporting with winding time measurement result, the described value of reporting is reported radio network controller, and the numerical value of described winding time quantization unit increases along with the increase of distance;

Step B. radio network controller positions terminal according to described value of reporting that the base station reports.

2. the localization method that utilizes the winding time as claimed in claim 1 is characterized in that described step B specifically comprises the following steps:

Described terminal reports transmitting-receiving time difference Rx-Tx measurement result, wireless network to radio network controller

Controller positions described terminal according to described value of reporting that Rx-Tx measurement result and base station report.

3. the localization method that utilizes the winding time as claimed in claim 2 is characterized in that, further comprises the following steps: before the described step B

Described radio network controller indicates described terminal to receive and dispatch the measurement of time difference Rx-Tx.

4. the localization method that utilizes the winding time as claimed in claim 1 is characterized in that, the quantization unit that the described winding time is set in the described steps A is 0.0625chips in 8.5 kilometer range.

5. the localization method that utilizes the winding time as claimed in claim 1 is characterized in that, the bit wide of described winding time value of reporting is 15 bits.

6. the localization method that utilizes the winding time as claimed in claim 1 is characterized in that, in described steps A, according to the cell coverage area of reality described quantization unit is set.

7. the localization method that utilizes the winding time as claimed in claim 6 is characterized in that the process that described quantization unit is set comprises the following steps: in described steps A

Cell coverage area according to reality obtains corresponding winding time maximum;

Zero in peaked scope of described winding time, increase segmentation along with the increase of distance described winding time quantization unit is set.

8. as claim 1 or the 6 or 7 described localization methods that utilize the winding time, it is characterized in that described segmentation is set to equidistantly or the segmentation setting of non-equidistance.

9. the localization method that utilizes the winding time as claimed in claim 8 is characterized in that, the quantization unit of described segmentation is a kind of or combination in arithmetic progression, the Geometric Sequence.