WO2005029723A1

WO2005029723A1 - Mobile communication terminal

Info

Publication number: WO2005029723A1
Application number: PCT/JP2003/011911
Authority: WO
Inventors: Koichi Yamashita; Hideto Aikawa; Akihiro Shibuya
Original assignee: Mitsubishi Denki Kabushiki Kaisha
Priority date: 2003-09-18
Filing date: 2003-09-18
Publication date: 2005-03-31
Also published as: JPWO2005029723A1

Abstract

A mobile communication terminal includes a path search device (1) for identifying a path used for RAKE reception. In the path search device (1), a path detection section (12) including a particular number of path detectors (12-1, 12-2, ...) measures a reception power of the pilot signal contained in the reception signal, so as to detect a plurality of paths present within a constant time from a predetermined reference path timing and a path detection controller (11) controls path detection by notifying peripheral cell information including the reference path timing to the path detection section (12) according to a cell allocation plan table (14). Each of the path detectors executes path detection by time division according to the cell information notified from the path detection controller (11).

Description

Description Mobile communication terminal Technical field

The present invention relates to a mobile communication terminal adopting a CDMA (Code Division Multiple Access) system as a communication system. More specifically, the present invention measures a pilot signal power of a nearby radio base station, and The present invention relates to a mobile communication terminal having a configuration for specifying a path used for AKE reception. Technology

Hereinafter, a conventional mobile communication terminal (receiving device) will be described. In the DS-C DMA (Direct Sequence-Code Division Multiple Access) fef method, the information data signal is spread over a wide band using a chip transmission rate higher than the report data transmission rate and transmitted. Despreading using the spreading code used for spreading enables multiple access. In mobile communications (especially land mobile communications), communication is often out of line of sight, and multiple propagation paths from various directions with different arrival times are formed due to reflection from buildings. This multiple propagation path causes a fluctuation in the level of the received signal called fuzzing, which adversely affects the communication quality. Therefore, in the DS-C DMA communication system, at the time of demodulation, the signal of each delay path is separated from the received signal, and these are combined and received by the RAKE receiver to improve the communication quality. Here, since it is necessary to separate each delay path signal from the received signal, path detection processing is important.

Next, a conventional path detection process will be described. Normally, in the path detection processing, a threshold value is set to separate path signals. That is, in the receiving apparatus, the path detecting unit transmits the position information of the path having a value equal to or larger than the threshold value to the RAKE receiving circuit, and the RAKE receiving circuit performs RAKE combining based on the notified path position information. Row PC orchid 003/011911

2

Yeah. As a result, a path-diverse effect can be obtained, and communication quality can be improved.

In mobile communications, when the threshold is set steadily, taking into account attenuation due to the distance between the mobile station and the base station, and the time change of fusing due to position fluctuation, etc. Since the communication quality (reception characteristics) power obviously deteriorates, it is necessary to estimate the threshold value by the initial value and one measurement unit. Therefore, as a method for path detection, for example, a method of setting a threshold based on the average power of a delay profile or a method of setting a threshold based on a maximum value and a minimum value is considered. Have been. In a conventional receiver using the above-described path detection method (see Patent Document 1 below), for example, a floor level of the delay profile is obtained by calculating an average power of a measured delay profile. . The floor level is a value calculated by multiplying the average power by an appropriate constant value. Then, at the time of path detection, the values below the floor level are removed, the position detection data ¾ is reduced, and then the correlation peak value is searched. As a result, the amount of search data in the correlation peak value search can be reduced, and the search processing speed can be further increased.

Patent Document 1.

In the conventional mobile communication terminal (receiving device), as the number of cells to be measured for which the path is to be detected increases as the number of cells to be measured increases, Since the time required for the path search (a series of processes from the intimacy distribution measurement based on the delay profile to the path detection based on the threshold determination) becomes longer, the first path detected becomes older and the reliability increases. There is a problem that the performance is impaired. In particular, when the mobile communication terminal moves at high speed, the effect tends to be remarkable.

Also, in order to avoid the above problem, the path detectors are equipped with path detectors for the number of neighboring cells, which can reduce the time required for path detection. On the other hand, the path detectors that operate simultaneously Power consumption and required resources 11911

Three

There was a problem that it increased in width.

The present invention has been made in view of the above, and an object of the present invention is to provide a mobile communication terminal that can reduce power and resources consumed in path detection while performing path detection under optimal conditions. . Disclosure of the invention

The mobile communication terminal according to the present invention includes a path search device for specifying a path used for RAKE reception, and the path search device measures reception power of a pilot signal included in a received signal. By doing so, a path detecting means including a specific number of path detectors for detecting a plurality of paths existing within a predetermined time (path detection range) from a predetermined quasi-path timing '(the embodiment described later) The cell information including the reference path timing according to the cell allocation information in which the path detection operation start time is associated with each path detector for each cell. Means for controlling the path detection by the specified number of path detectors by notifying the path detection means (path detection control unit: equivalent to I1). Each path detector is on the basis of the path detection control cell information notified from the means [delta], and executes in a time division path detection.

According to the present invention, by performing the path search in a time division manner, the path detection of many peripheral cells is performed by a small number of path detectors (less than the number of peripheral cells). Also, for example, the path detection time for one cell is reduced, and the path detection for one cell is repeatedly executed. Brief Description of Drawings

FIG. 1 is a diagram showing a configuration of a mobile communication terminal (path search device) according to a first embodiment of the present invention. FIG. 2 is a diagram showing an example of a cell allocation plan table. FIG. 5 is a flowchart showing the operation of the path search device ft according to the first embodiment. FIG. 4 is a diagram illustrating the structure of the mobile communication terminal search device according to the second embodiment of the present invention. FIG. 5 is a flowchart showing the operation of the path search device according to the second embodiment, and FIG. 6 is a flowchart showing the operation of the path search device according to the second embodiment. FIG. 7 is a diagram showing the configuration of a mobile communication terminal (path search device) according to a third embodiment of the present invention. FIG. 8 is a diagram showing the operation of the path search device of the third embodiment. FIG. 9 is a diagram showing a configuration of a mobile communication terminal (path search device) according to a fourth embodiment of the present invention. FIG. 10 is a flowchart of the fourth embodiment. FIG. 11 is a flowchart showing the operation of the path search device of FIG. 11. FIG. 11 is a diagram showing a fixed time range (path detection range) centered on the reference path timing given to the path detection unit 12. Figure 12 shows the time range that can be detected by the path detection unit 12. FIG. 13 is a flowchart showing a process corresponding to step S1 of the first to fourth embodiments. BEST MODE FOR CARRYING OUT THE INVENTION

In order to explain the present invention in more detail, this will be described with reference to the accompanying drawings. Embodiment 1,

FIG. 1 is a diagram showing a configuration of a first embodiment of a path search device in a mobile communication terminal (receiving device) according to the present invention, specifically, a mobile communication terminal. The illustrated path search device 1 includes a path detection control unit 11 that controls path detection based on a plurality of cell information input from the outside, and a plurality of path search units based on the cell information received from the path detection control unit 11. A path detection section 12 for detecting paths, a path search result collection section 13 for totalizing and managing a plurality of pieces of path information output from the path detection section 12 in units of cells, and a path detection control section 1 1 is composed of a cell allocation table 14 used for allocating cells to the path detection unit 12. The path detection unit 12 includes a plurality of path detectors 12-1—1, 12-2. , 1 2— 3….

FIG. 2 is a diagram showing an example of a cell allocation meter table 14. Here, for example, a case where a maximum of 16 cells are allocated to four path detectors will be described. ing. This cell allocation meter table 14 has one path detection operation for each cell. It associates a numerical value (path detection start time) that specifies the elapsed time or start time in units of time to be detected with a number that specifies each path detector. The numerical value associated with the start time and the number specifying the path detector indicates the number specifying the cell.

Here, the operation of the path search device 1 will be described in detail with reference to the drawings. FIG. 3 is a flowchart showing the operation of the path search device.

First, the path detection controller 11 collects a plurality of pieces of cell information input from the outside (FIG. 3, step S1). Then, the cell information is set in the path detection unit 12 based on the cell allocation plan table 14 and the time at that time (step S 2). At this time, if the path detector 12 is composed of a plurality of path detectors, cell information corresponding to the number is set.

Next, the path detection unit 12 measures the received power of the pilot signal based on the set cell information, thereby obtaining a plurality of signals existing at a fixed time ら from the reference path timing ′ included in the cell information. Is detected (step S3). At this time, the path detection unit 12 performs a path detection operation until a predetermined time set so as to delay the path detection time is reached, and then outputs a detected path.

Next, the path search result totaling section 13 collects the detected paths output from the path detecting section 12 (step S4), and averages the received level for each detected path (step S5). . Here, as the averaging method, for example, a method of calculating the average of the reception levels of the past detection paths (for the specified number of times) or the time elapsed since the detection of the reception level of the past detection paths A method of multiplying by a coefficient corresponding to and adding.

Next, the path search result totaling unit 13 collectively outputs the detected path information obtained by averaging, for example, path timing and reception level, to the outside (step S6). Thereafter, when continuously performing a path search for each cell, the path detection unit 12 continues the path search based on the cell allocation plan table 14 unless externally controlled to stop the path detection (Step S). 7). As described above, in the present embodiment, by performing the path search in a time-division manner, the path detection of many peripheral cells is performed by a small number of path detectors (less than the number of peripheral cells). Further, by reducing the path detection time for one cell, the difference between the path detection timings in each cell is reduced. Thereby, the reliability of the path detection result for each cell can be made equal. Furthermore, the power consumption can be significantly reduced compared to the conventional technology in which path detectors K are provided with path detectors for the number of peripheral cells and operate them simultaneously. Further, since path detection for one cell is repeatedly performed, it is possible to obtain the same degree of path detection as when performing path detection for a long time.

Embodiment 2

FIG. 4 is a diagram showing a configuration of a mobile communication terminal (receiving device) according to the present invention, specifically, an embodiment of a path search device in the mobile communication terminal. The path search device 1a includes a path detection control unit 11a that controls path switching based on a plurality of cell information input from the outside, and a plurality of paths output from the path detection unit 12. It has a path search result aggregation unit 13a that aggregates and manages ^ in cell units, and a path power determination unit 15 that determines whether the received power of the detected path exceeds a specific threshold. The same components as those in FIG. 1 of Embodiment 1 described above are denoted by the same reference numerals, and description thereof will be omitted.

In the present embodiment, when the determination result of the path power determination unit 15 exceeds the threshold, the number of repetitions of the operation of the path detection control unit 11 a and the path detection unit 12 is reduced. . '

Here, the operation of the path search device 1a will be described in detail with reference to the drawings. FIG. 5 is a flowchart showing the operation of the path search device 1a. Here, only the processing different from FIG. 3 of Embodiment 1 described above will be described. For example, the path result summation unit 13a outputs the detection path information obtained by averaging, for example, the path timing and the reception level, etc., to the outside at once, and after t (step S6), The path power determination unit 15 sets the reception power of the detected path in advance. The power threshold value is compared with the threshold value (FIG. 5, step S8). This dagger comparison operation is performed when a specific time has elapsed from the start of the path search execution.

Then, in the t-shadow comparison process of step S8, for example, if the received power of the detected / exceeded power exceeds the above power threshold value (step S8, OK), the path detection control unit 1a holds the received power. The path detection end number parameter, that is, the number of repetitions of path detection is reduced (step S9). On the other hand, when the reception power of the detection path is equal to or lower than the above power threshold (step S8, NG), the current path detection end count parameter is held.

Finally, the path detection control unit 11 determines the end of the path search operation based on the path detection end number parameter (step S10).

Thus, in the present embodiment, according to the power of the detection path, that is, when the reception power of the detection path is sufficiently large, the path detection operation is terminated in the middle, whereby the path detection operation is performed. The number of repetitions was reduced (operation time was shortened). As a result, the power and processing time consumed in the path search can be further reduced.

Note that, in the present embodiment, a case has been described where the current path detection end number parameter is held when the received power of the detected path is equal to or lower than the above power threshold value (step S8, NG). Instead, for example, as shown in FIG. 6, the number of repetitions of the path detection operation may be increased (operation time is increased) (FIG. 6, step S11).

Embodiment 3.

FIG. 7 is a diagram showing a configuration of a third embodiment of a path search device in a mobile communication terminal (receiving device) according to the present invention. The path search device 1b includes a path power determination unit 15b that determines whether the reception power of the detected path exceeds a specific threshold, a movement speed detection unit 16 that detects the movement speed, A path power threshold generator 17 for generating a threshold for path power determination based on the moving speed detected by the moving speed detector 16. Note that the same components as those in the first or second embodiment described above are denoted by the same reference numerals and description thereof is omitted. To do.

The present embodiment utilizes the fact that the peripheral cell and path power fluctuate greatly during high-speed movement, and relatively slowly during low-speed movement or in a stationary state. Set high values for / and, and set low power thresholds when moving at low speeds.

Here, the operation of the path search device 1b will be described in detail with reference to the drawings. FIG. 8 is a flowchart showing the operation of the path search device 1b. Here, only the processing different from the first or second embodiment described above will be described. For example, the moving speed detector 16 detects the moving speed of the mobile communication terminal equipped with the path search device 1b of the present embodiment (FIG. 8, step S21). Then, the path power threshold generation unit .17 generates a power threshold to be used by the path power determination unit 15b based on the detected moving speed (step S22). That is, a power threshold higher than the reference is generated during high-speed movement, and a power threshold lower than the reference is generated during low-speed movement. Note that the processing related to the moving speed in step S21 and step S22 is not limited to FIG. 8, and is performed before the end of the pass search operation (step S10). This can be done wherever the order is followed.

As described above, in the present embodiment, the power threshold during high-speed movement is set high, and the power threshold during low-speed movement is set low, and the path detection is repeated according to the movement speed. The number was changed. As a result, it is possible to reduce the power consumption and processing speed when moving at low speeds without compromising the path detection accuracy of high-speed moving day temples, and to always perform path detection under optimal conditions according to the communication environment. it can.

Embodiment 4.

FIG. 9 is a diagram showing a horizontal configuration of a mobile communication terminal (receiving device) according to the present invention, specifically, a fourth embodiment of a path search device in a mobile communication terminal. The path search device 1c includes a path detection control unit 11c that controls path detection based on a plurality of pieces of cell information input from the outside, and a reception power of a detected path exceeding a specific threshold. A path power determination unit 15c for determining whether or not to perform the operation, and an intermittent operation control unit 18 for managing the start timing of the intermittent operation. The same components as those in the first, second, or third embodiment described above are denoted by the same reference numerals, and description thereof is omitted. In the present embodiment, the intermittent operation control unit 18 obtains an optimal intermittent operation interval based on the surrounding path power and the moving speed, and adjusts the intermittent operation frequency. In addition, the intermittent operation control unit 18 holds the criterion value of the intermittent operation interval, and corrects the intermittent operation interval based on the moving speed information detected by the moving speed detecting unit 16.

Here, the operation of the path search device 1c will be described in detail with reference to the drawings. No.

FIG. 10 is a flowchart showing the operation of the path search device 1c. Here, only the processing different from the first, second, or third embodiment described above will be described.

For example, after the path detection control unit 1 lc reduces the number of path detection repetitions (path detection end number parameter) stored therein (10th step, step S9), the 欠 operation control unit 18 The optimum intermittent operation interval is determined based on the peripheral path power and the moving speed, and the intermittent operation frequency is adjusted (step S31).

Then, the path detection controller 1 1 c determines the end of the path search operation based on the path detection end frequency parameter (step S 10). After that, the intermittent operation controller 18 determines whether to stop the intermittent operation. (Step S32), for example, if an instruction to stop the intermittent operation is received from outside (Step S32, Yes), the intermittent operation is stopped. On the other hand, if the instruction to stop the intermittent operation has not been received (step S32, No), the intermittent operation frequency is adjusted based on the moving speed of the mobile communication terminal (step S33), and the path search operation is performed. It is stopped (step S34) and waits until the next operation start time.Step S33 is a process for correcting the intermittent operation interval. On the other hand, when moving at high speed, the intermittent operation interval is shortened to follow the path fluctuation, and in step S31, the intermittent operation interval is captured when the path power threshold and the value judgment are OK. As described above, in the present embodiment, based on the peripheral path power and the moving speed, T JP2 drawing 11911

Ten

To determine the optimal intermittent operation interval and adjust the intermittent operation frequency. This makes it possible to further reduce the power and processing time consumed in the path search when moving at a low speed, and further improve the path detection accuracy when moving at a high speed.

Embodiment 5

In the fifth embodiment, the path detection control units (11, 11a, 11c) described in the first to fourth embodiments specify the reference path timing separately from the cell information having the specific reference path timing. Cell information is generated with reference to the timing obtained by adding and subtracting the time difference between the two, and the information is set in the path detection unit 12.

FIG. 11 is a diagram showing a fixed time range (corresponding to the path detection range in Embodiments 1 to 4) centered on the reference path timing ′ given to the path detection unit 12. This time range is often determined at the configuration stage of the device, but in the present embodiment, as shown in FIG. 12, the path detection range detectable by the path detection unit is dynamically increased after the configuration of the attire.

FIG. 13 is a flowchart showing a process corresponding to step S1 in the first to fourth embodiments. In this embodiment, the path detection control unit adds the time range to the reference path timing within the time range detectable by the path detection unit 12 based on the acquired cell information of the path detection target, and Another cell information is generated with the subtracted timing as the reference nos timing (steps S41, S42).

As described above, in the present embodiment, the path detection range that can be detected by the path detection unit can be dynamically increased after the device is configured. As a result, the path detection range can be expanded, so that the accuracy of path detection can be further improved. Industrial applicability

As described above, the mobile communication terminal according to this effort is useful for a system that employs CDMA as a communication method.In particular, it measures the pilot signal power of nearby wireless base stations and uses it for RAKE reception. ! / Mobile communication terminal with a configuration to specify the path Suitable for

Claims

The scope of the claims

1. In a mobile communication terminal equipped with a path search device for specifying a bus used for RAKE reception,

The path search device,

By measuring the received power of the pilot signal included in the received signal, a specific number of path detections that detect multiple paths existing within a certain time (path detection dry space) from a predetermined reference path timing Path detecting means including a detector,

According to the cell allocation information in which the path detection operation start time and the individual path detectors are associated with each other for each cell, by notifying peripheral path information including the reference path timing to the path detection means, Path detection control means for controlling path detection by the path detector;

With

A mobile communication terminal, wherein each path detector included in the path detection means performs path detection in a time division manner based on the cell information notified from the path detection control means.

2. Further, a path power comparison method for comparing the reception power of the detected path with a predetermined power threshold value for determining the end of path detection,

With

When the received power of the detected path exceeds the power threshold value according to the comparison result, the path detection control means terminates path detection and shortens the operation time required for noise search. The mobile communication terminal according to claim 1, wherein

3. A mobility detecting means for detecting a moving speed of the terminal,

Based on the detected moving speed! Power threshold generation means for generating a power threshold used by the path power ratio means; The mobile communication terminal according to claim 15, wherein the mobile communication terminal includes:

4. Further, based on the received power of the detection path before and after 15 moving speeds, or based on the moving speed, an optimum intermittent operation interval is determined, and an intermittent operation control means for adjusting the intermittent operation frequency,

4. The mobile communication terminal according to claim 3, comprising:

5. Further, a path power comparison unit for comparing the reception power of the detection path with a predetermined power threshold for judging the end of path detection,

With

2. The mobile communication terminal according to claim 1, wherein the path detection control means controls a reduction in an operation time required for a path search according to the comparison result.

6. A moving speed detecting means for detecting a moving speed of the terminal,

Power threshold generation means for generating a power threshold used by the path power comparison means based on the detected moving speed;

6. The mobile communication terminal according to claim 5, comprising:

7. Further, based on the received power of the detection path and the self-moving speed, or the moving speed, an optimal intermittent operation interval is determined, and an intermittent operation control means for adjusting the intermittent operation frequency,

7. The mobile communication terminal according to claim 6, wherein the mobile communication terminal has an IB.

8. The path detection control unit generates, in addition to the cell information including the reference path timing, another cell information that shortens a time range detectable by the path detection unit, and sets the path detection range. The mobile communication terminal according to claim 1, characterized in that the mobile communication terminal is dynamically added.