JP2001189970A - Channel measurement control method, mobile station and mobile communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decide on a proper measurement period, so as to measure a channel (e.g., perch tree channel) with the measurement period. SOLUTION: The perch tree channel is measured (S301), the measurement period is decided (S302-S306) on the basis of a state of the measured perch channel (e.g., number of channels). For example, when the number of perch channels is large, the measurement period is reduced, and when the number of perch channels is few, the measurement period is extended.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a channel measurement control method, a mobile station, and a mobile communication system for determining an appropriate measurement period and measuring a channel (for example, a perch channel) at the measurement period.

[0002]

2. Description of the Related Art Conventionally, in a mobile communication system, a mobile station has detected one or more channels transmitted by one or more base stations and made a communication request to one or more base stations.

For example, CDMA (Code Division Multipl
In e-Access) communication, there is a technique called diversity handover (hereinafter referred to as "DHO"). This is a technique in which a mobile station simultaneously receives a plurality of downlink signals transmitted from the same divided base station or a plurality of downlink signals transmitted from a plurality of base stations, and eliminates communication interruption.

In the present technology, a mobile station detects a channel (for example, a perch channel) transmitted by a plurality of or a single base station by a plurality of different radios. By detecting the perch channel, the mobile station recognizes that there is a DHO-connectable downlink signal, and performs DHO by transmitting a DHO request to the base station.

[0005] Further, even after the detection of the perch channel, the mobile station measures the perch channel at a constant period. This is due to the perch channel the mobile station is measuring,
This is to determine whether HO connection is possible or not.

FIG. 1 is a flowchart showing an example of a conventional channel measurement process. In step S101, the communicating mobile station measures a perch channel. next,
Proceeding to step S102, the measurement period T is set to a perch channel measurement period Ta that is a constant value. The mobile station performs step S
In 103, a timer is issued based on the measurement period T determined in step S102, and when the timer expires, the perch channel is measured again. As described above, in the related art, the perch channel measurement is always performed at a constant cycle.

[0007]

However, when a mobile station has a plurality of perch channels immediately below a base station or the like,
In a region where the reception power of the perch channel and the reception quality fluctuate drastically, if the measurement is performed at regular intervals, which is the conventional technology, the mobile station cannot follow the fluctuation of the perch channel between measurements. , The determination of DHO connection possible / impossible is delayed, and in the worst case, communication is disconnected. Also, when the mobile station is in a stationary state or the like, and the reception power and reception quality of the perch channel are very stable, the measurement at regular intervals, which is the conventional technique, is more than necessary and consumes battery power. Has been invited. As described above, the conventional technique has a problem.

Therefore, an object of the present invention is to determine an appropriate measurement period and measure a channel in the measurement period.

[0009]

[Means for Solving the Problems] The measurement period of a channel is defined as
Channel status (number of channels, received power, received quality,
It is considered that by making the variable according to propagation loss, propagation delay, etc., communication can be stabilized and power consumption of the receiving device can be reduced. More specifically, if the conditions for maintaining communication are insufficient, or if it is possible to anticipate a situation in which the current condition is sufficient but may be insufficient in the near future, the measurement period of the perch channel is shortened, and To obtain the channel status. In addition, when the mobile station is in a state sufficient to continue communication well, the mobile station extends the channel measurement cycle to reduce power consumption.

[0010] In order to achieve the above object, an invention according to claim 1 is a channel for a mobile station which detects one or more channels transmitted by one or more base stations and issues a communication request to one or more base stations. A measurement control method, comprising: a measurement step of measuring the channel; and a control step of determining a measurement cycle in the measurement step based on a state of the channel measured in the measurement step, wherein the measurement step includes the control step The channel is measured at a measurement cycle determined by:

The invention according to claim 2 is the channel measurement control method according to claim 1, wherein the control step determines a measurement cycle in the measurement step based on the number of channels measured in the measurement step. It is characterized by doing.

According to a third aspect of the present invention, there is provided the channel measurement control method according to the first aspect, wherein the control step sets a measurement cycle in the measurement step based on a reception power of the channel measured in the measurement step. It is characterized in that it is determined.

According to a fourth aspect of the present invention, there is provided the channel measurement control method according to the first aspect, wherein the control step is performed based on a variation in received power of the channel measured in the measurement step. The measurement cycle is determined.

According to a fifth aspect of the present invention, there is provided the channel measurement control method according to the first aspect, wherein the control step sets a measurement cycle in the measurement step based on reception quality of the channel measured in the measurement step. It is characterized in that it is determined.

According to a sixth aspect of the present invention, there is provided the channel measurement control method according to the first aspect, wherein the control step is performed based on a variation in reception quality of the channel measured in the measurement step. The measurement cycle is determined.

According to a seventh aspect of the present invention, there is provided the channel measurement control method according to the first aspect, wherein the control step sets a measurement cycle in the measurement step based on a channel propagation loss measured in the measurement step. It is characterized in that it is determined.

According to an eighth aspect of the present invention, there is provided the channel measurement control method according to the seventh aspect, wherein the control step shortens a measurement period when the propagation loss is small, and reduces the measurement period when the propagation loss is large. It is characterized in that the measurement cycle is lengthened.

According to a ninth aspect of the present invention, there is provided the channel measurement control method according to the first aspect, wherein the control step is performed based on a variation in channel propagation loss measured in the measurement step. The measurement cycle is determined.

According to a tenth aspect of the present invention, there is provided the channel measurement control method according to the first aspect, wherein the control step sets a measurement cycle in the measurement step based on a propagation delay of a channel measured in the measurement step. It is characterized in that it is determined.

The invention according to claim 11 is the channel measurement control method according to claim 10, wherein the control step shortens a measurement cycle when the propagation delay is small.
When the propagation delay is large, the measurement cycle is lengthened.

According to a twelfth aspect of the present invention, there is provided the channel measurement control method according to the first aspect, wherein the control step is performed based on a variation amount of a channel propagation delay measured in the measurement step. The measurement cycle is determined.

According to a thirteenth aspect of the present invention, there is provided the channel measurement control method according to the first aspect, wherein the control step includes the step of measuring based on the number of channels, reception power, and reception quality measured in the measurement step. It is characterized in that a measurement cycle in the step is determined.

According to a fourteenth aspect of the present invention, in the channel measurement control method according to the first aspect, the control step includes performing the measurement based on the number of channels, propagation loss, and propagation delay measured in the measurement step. It is characterized in that a measurement cycle in the step is determined.

According to a fifteenth aspect of the present invention, in the channel measurement control method according to the first aspect, the control step comprises the steps of: measuring the number of channels, reception power, reception quality, propagation loss, The measurement cycle in the measurement step is determined based on the propagation delay.

According to a sixteenth aspect of the present invention, there is provided a mobile station for detecting one or more channels transmitted by one or more base stations and making a communication request to one or more base stations, wherein the measurement is performed for measuring the channels. Means, and control means for determining a measurement cycle by the measurement means based on the state of the channel measured by the measurement means, wherein the measurement means measures the channel at the measurement cycle determined by the control means. Features.

According to a seventeenth aspect of the present invention, in the mobile station according to the sixteenth aspect, the control means determines a measurement cycle in the measuring means based on the number of channels measured by the measuring means. It is characterized by.

The invention according to claim 18 is the mobile station according to claim 16, wherein the control means determines a measurement period in the measurement means based on the reception power of the channel measured by the measurement means. It is characterized by the following.

According to a nineteenth aspect of the present invention, in the mobile station according to the sixteenth aspect, the control unit is configured to determine a measurement period in the measuring unit based on a variation in received power of the channel measured by the measuring unit. Is determined.

According to a twentieth aspect of the present invention, in the mobile station according to the sixteenth aspect, the control means determines a measurement cycle in the measuring means based on the reception quality of the channel measured by the measuring means. It is characterized by the following.

According to a twenty-first aspect of the present invention, in the mobile station according to the sixteenth aspect, the control unit is configured to determine a measurement period in the measurement unit based on a variation in reception quality of the channel measured by the measurement unit. Is determined.

According to a twenty-second aspect of the present invention, in the mobile station according to the sixteenth aspect, the control means determines a measurement period in the measuring means based on a channel propagation loss measured by the measuring means. It is characterized by the following.

According to a twenty-third aspect of the present invention, in the mobile station according to the twenty-second aspect, the control means shortens a measurement period when the propagation loss is small, and measures the measurement period when the propagation loss is large. It is characterized in that the period is lengthened.

According to a twenty-fourth aspect of the present invention, in the mobile station according to the sixteenth aspect, the control unit determines a measurement period in the measurement unit based on a variation in channel propagation loss measured by the measurement unit. Is determined.

According to a twenty-fifth aspect of the present invention, in the mobile station according to the sixteenth aspect, the control means determines a measurement period in the measurement means based on a channel propagation delay measured by the measurement means. It is characterized by the following.

According to a twenty-sixth aspect of the present invention, in the mobile station according to the twenty-fifth aspect, the control means shortens the measurement period when the propagation delay is small, and measures the measurement period when the propagation delay is large. It is characterized in that the period is lengthened.

According to a twenty-seventh aspect of the present invention, in the mobile station according to the sixteenth aspect, the control unit determines a measurement period in the measurement unit based on a variation amount of a propagation delay of a channel measured by the measurement unit. Is determined.

According to a twenty-eighth aspect of the present invention, in the mobile station according to the sixteenth aspect, the control means determines the number of channels, reception power, and reception quality measured by the measurement means. The measurement cycle is determined.

According to a twenty-ninth aspect of the present invention, in the mobile station according to the sixteenth aspect, the control unit determines the number of channels, propagation loss, and propagation delay measured by the measuring unit. The measurement cycle is determined.

According to a thirtieth aspect of the present invention, in the mobile station according to the sixteenth aspect, the control means includes: a number of channels, reception power, reception quality, propagation loss, and propagation delay measured by the measurement means. The measurement cycle in the measuring means is determined based on the following.

According to a thirty-first aspect of the present invention, there is provided a mobile communication system, comprising: the mobile station according to any one of the sixteenth to thirty aspects; and a base station for communicating with the mobile station. And

According to the above configuration, an appropriate measurement period can be determined, and the channel can be measured in the measurement period. Thereby, for example, the DHO followability can be improved and communication can be stabilized. In addition, reduction of battery consumption can be realized.

[0042]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 2 is a diagram showing a configuration example of a mobile station according to the embodiment of the present invention. FIG. 3 conceptually shows a part of the configuration of the mobile station that is particularly relevant to the present invention.

The mobile station 200 includes a control unit 201 and a radio unit 202. The control unit 201 has a function of controlling the wireless unit 202, and includes a timer control unit 203 and a perch channel measurement control unit 204. Wireless unit 204
Has a function of communicating with a base station and includes a measurement unit 205. The timer control unit 203 is connected to the perch channel measurement control unit 204, and controls timer driving and the like. The perch channel measurement control unit 204 is connected to the timer control unit 203 and the measurement unit 205, and has a function of instructing measurement of the perch channel, a function of determining a measurement cycle based on the measurement result reported from the measurement unit 205, It has a function of instructing a timer value and a function of storing a measurement result. Measurement unit 205
Is connected to the perch channel measurement control section 204, performs perch channel measurement according to the instruction of the perch channel measurement control section 204, and receives the received power (for example, RSSI
(Received Signal Strength Indicator), reception quality (for example, SIR (Signal to Interference power Ra)
tio) etc.).

Perch channel measurement control section 204 determines a measurement cycle based on the measurement result reported from measurement section 205. This is different from the prior art in which the measurement period is always constant. In the present embodiment, the perch channel is measured, and the measurement period is determined based on the state of the perch channel.However, a channel other than the perch channel is measured, and the measurement period is determined based on the state of the channel. Is also good.

Hereinafter, a specific example of the channel measurement control will be described with reference to a flowchart.

(Channel Measurement Control 1) FIG. 3 is a flowchart showing an example of processing in the case where the measurement period is determined based on the number of perch channels measured by the mobile station and channel measurement is performed. In this channel measurement control, the measurement cycle is shortened when the number of perch channels is large, and the measurement cycle is lengthened when the number of perch channels is small.

In step S301, a mobile station in communication measures a perch channel. Step S30
In 2, the number N of the measured perch channels is compared with a threshold number Nlarge of the number of perch channels for shortening the measurement period, which is preset in the mobile station. Number of perch channels N
Is larger than the threshold Nlarge, it can be estimated that the mobile station is in a zone where a large number of zones are densely located in a short distance, such as immediately below the base station, and the reception power of the perch channel being measured, the sharpness of the reception quality Since a change is assumed to occur, the mobile station changes the measurement cycle T to a shorter interval Tshort in step S303. Number of perch channels N
Is smaller than the threshold Nlarge, the mobile station proceeds to step S30.
Then, in step S304, the measured number N of perch channels is compared with the threshold Nsmall of the number of perch channels for extending the measurement cycle, which is preset in the mobile station. When the number N of perch channels is smaller than the threshold value Nsmall, it is assumed that the mobile station is relatively far from the base station, and that the received power of the perch channel being measured does not cause a sharp change in reception quality. In step S305, the mobile station sets the measurement period T to a longer interval T
Change to long (> Tshort). If the number N of perch channels is larger than the threshold Nsmall, the mobile station proceeds to step S306.
The measurement period T is set to the standard interval Tnormal (Tshort <Tnorma
l <Tlong). In step S307, the mobile station issues a timer based on the measurement cycle T determined in the above-described step, and when the timer expires, measures the perch channel again.

In the present channel measurement control, the measurement cycle to be determined has three stages of Tshort, Tnormal and Tlong, but may be two stages or four or more stages.

(Channel Measurement Control 2) FIG. 4 shows the reception power (for example, RSS) of the perch channel measured by the mobile station.
11 is a flowchart illustrating a processing example in the case where a measurement cycle is determined based on I) and channel measurement is performed. In step S401, the communicating mobile station measures a perch channel. In step S402, the measured reception power P of the perch channel is compared with a perch channel reception power threshold Plow for measurement cycle shortening preset in the mobile station.

As the reception power P, for example, it is conceivable to use the maximum value of the reception power of the perch channel of the base station (channel) with which the mobile station is currently communicating. The base station (channel) with which the mobile station is currently communicating
It is also conceivable to use the minimum value or the average value of the received power of the perch channel. Furthermore, it is conceivable to use the reception power of the perch channel (which is performing the measurement) of the base station (channel) with which the mobile station is not currently communicating.

When the perch channel reception power P is smaller than the threshold value Plow, the mobile station is currently receiving sufficient power, but it is assumed that the mobile station will be in an insufficient state in the near future, and In step S403, the measurement cycle T is changed to a shorter interval Tshort. If the perch channel reception power P is larger than the threshold value Plow, the mobile station proceeds to step S404. In step S404, the measured perch channel reception power P and the perch channel for measurement period extension preset in the mobile station are set. Compare with the reception power threshold Phigh. If the perch channel reception power P is larger than the threshold value Phigh, the mobile station has received enough power, and it is assumed that the mobile station can withstand even a change in the state in the near future. S4
At 05, the measurement period T is changed to a longer interval Tlong. If the perch channel reception power P is smaller than the threshold value Phigh, the mobile station proceeds to step S406, and changes the measurement cycle T to the standard interval Tnormal. The mobile station performs step S40.
In step 7, a timer is issued based on the measurement period T determined in the above step, and when the timer expires, the perch channel is measured again.

(Channel Measurement Control 3) FIG. 5 is a flowchart showing an example of processing in a case where a measurement cycle is determined based on the fluctuation amount of the received power of the perch channel measured by the mobile station and channel measurement is performed. Here, the fluctuation amount of the reception power is an absolute value of a difference between the reception power measured this time and the reception power measured last time. In step S501, the communicating mobile station measures a perch channel. In step S502, a variation amount Cp of the received power is calculated from the absolute value of the difference between the measured received power P of the perch channel and the previously measured received power Plast.

As the received power fluctuation amount Cp, for example, it is conceivable to use the maximum value of the received power fluctuation amount of the perch channel of the base station (channel) with which the mobile station is currently communicating. It is also conceivable to use the minimum or average value of the fluctuation amount of the received power of the perch channel of the base station (channel) with which the mobile station is currently communicating. Further, it is conceivable to use the amount of fluctuation in the received power of the perch channel of the base station (channel) with which the mobile station is not currently communicating.

In step S503, the calculated variation amount Cp of the received power and the threshold value Cpbig of the perch channel reception power variation for shortening the measurement period preset in the mobile station.
Compare with If the fluctuation amount Cp of the perch channel reception power is larger than the threshold value Cpbig, the mobile station is assumed to be in an area where the reception power changes abruptly. Therefore, the mobile station shortens the measurement period T in step S504. Change to interval Tshort. If the variation amount Cp of the perch channel reception power is smaller than the threshold value Cpbig, the mobile station proceeds to step S
Proceeding to 505, in step S505, the calculated perturbation channel reception power fluctuation amount Cp is compared with the perch channel reception power threshold Cpsmall for measurement period extension preset in the mobile station. If the variation amount Cp of the perch channel reception power is smaller than the threshold value Cpsmall, the mobile station is assumed to be in a stable area where the reception power does not change abruptly. Therefore, the mobile station sets the measurement period T in step S506. Change to a longer interval Tlong. If the variation amount Cp of the perch channel reception power is larger than the threshold value Cpsmall, the mobile station proceeds to step S507 and executes the measurement cycle T
To the standard interval Tnormal. The mobile station performs step S5
In 08, the measurement period T determined in the aforementioned steps
, A timer is issued, and when the timer expires, the perch channel is measured again.

(Channel Measurement Control 4) FIG. 6 shows the reception quality (for example, SIR) of the perch channel measured by the mobile station.
9 is a flowchart illustrating an example of a process in a case where a measurement cycle is determined based on the measurement period and channel measurement is performed. Step S
At 601, the communicating mobile station measures a perch channel. In step S602, the measured reception quality Q of the perch channel and the perch channel reception quality threshold for the measurement cycle shortening preset in the mobile station.
Compare with Qlow.

As the reception quality Q, similarly to the reception power P,
For example, it is conceivable to use the maximum value of the reception quality of the perch channel of the base station (channel) with which the mobile station is currently communicating.

If the perch channel reception quality Q is smaller than the threshold value Qlow, it is assumed that the mobile station has sufficient quality at present, but may be in an unsatisfactory state in the near future. In, the measurement cycle T is changed to a shorter interval Tshort. If the perch channel reception quality Q is greater than the threshold Qlow, the mobile station proceeds to step S
Proceeding to 604, in step S604, the measured perch channel reception quality Q and the perch channel reception quality threshold Qh for measurement period extension preset in the mobile station are set.
Compare with igh. Perch channel reception quality Q is threshold Qh
If the value is larger than igh, it is assumed that the mobile station has sufficient quality and can sufficiently withstand a change in the state in the near future.
Change the measurement period T to a longer interval Tlong. When the perch channel reception quality Q is smaller than the threshold Qhigh, the mobile station proceeds to step S606, and sets the measurement period T to the standard interval Tnormal.
Change to In step S607, the mobile station issues a timer based on the measurement period T determined in the above step, and when the timer expires, measures the perch channel again.

(Channel Measurement Control 5) FIG. 7 is a flowchart showing an example of processing in a case where a measurement period is determined based on a fluctuation value of the reception quality of the perch channel measured by the mobile station and channel measurement is performed. Here, the fluctuation amount of the reception quality is an absolute value of a difference between the reception quality measured this time and the reception quality measured last time. In step S701, the communicating mobile station measures a perch channel. In step S702, a variation amount Cq of the reception quality is calculated from the absolute value of the difference between the measured reception quality Q of the perch channel and the previously measured reception quality Qlast.

As the variation amount Cq of the reception quality, similarly to the variation amount Cp of the reception power, for example, the maximum variation amount of the reception quality of the perch channel of the base station (channel) with which the mobile station is currently communicating. It is conceivable to use a value or the like.

In step S703, the calculated variation amount Cq of the reception quality and the threshold value Cqbig of the perch channel reception quality variation amount for shortening the measurement period preset in the mobile station.
Compare with If the fluctuation amount Cq of the perch channel reception quality is larger than the threshold value Cqbig, it is assumed that the mobile station is located in an area where the reception quality changes rapidly. Therefore, the mobile station shortens the measurement period T in step S704. Change to interval Tshort. If the fluctuation amount Cq of the perch channel reception quality is smaller than the threshold value Cqbig, the mobile station performs step S
Proceeding to 705, in step S705, the calculated perturbation channel reception quality variation Cq is compared with the perch channel reception quality threshold Cqsmall for measurement period extension preset in the mobile station. If the fluctuation amount Cq of the perch channel reception quality is smaller than the threshold value Cqsmall, the mobile station is assumed to be in a stable area where the reception quality does not change rapidly, so the mobile station sets the measurement period T in step S706. Change to a longer interval Tlong. If the variation amount Cq of the perch channel reception quality is larger than the threshold value Cqsmall, the mobile station proceeds to step S707, and the measurement period T
To the standard interval Tnormal. The mobile station performs step S7
In 08, the measurement period T determined in the aforementioned steps
, A timer is issued, and when the timer expires, the perch channel is measured again.

(Channel Measurement Control 6) FIG. 8 is a flowchart showing an example of processing in the case where the measurement period is determined based on the perch channel propagation loss measured by the mobile station and channel measurement is performed. In step S801, the communicating mobile station measures the perch channel and receives the transmission power information of the broadcast perch channel.

The transmission power information of the perch channel may be transmitted and received separately from the perch channel,
The base station may transmit the signal in a perch channel, and the mobile station may receive and extract the signal. It is also conceivable that the transmission power of the perch channel is determined in advance so that the mobile station does not have to receive the information.

In step S802, the propagation loss L is calculated based on the measured perch channel reception power P and the received perch channel transmission power information. The propagation loss is obtained by dividing the transmission power by the reception power (d
It is a difference when thinking in B).

As the propagation loss L, similarly to the reception power P,
For example, it is conceivable to use the maximum value of the propagation loss of the perch channel of the base station (channel) with which the mobile station is currently communicating.

In step S803, the calculated propagation loss L is compared with a perch channel propagation loss threshold Llow for measurement period shortening preset in the mobile station. If the perch channel propagation loss L is smaller than the threshold Llow,
Since the mobile station is presumed to be directly below the base station, and it is assumed that a sudden change in the reception power and reception quality of the measured perch channel occurs, the mobile station performs step S80.
At 4, the measurement cycle T is changed to a shorter interval Tshort. If the perch channel propagation loss L is greater than the threshold Llow, the mobile station proceeds to step S805, and proceeds to step S8.
05, the calculated perch channel propagation loss L
And a permissible perch channel propagation loss threshold Lhigh for measurement period extension preset in the mobile station. If the perch channel propagation loss L is larger than the threshold Lhigh, it is estimated that the mobile station is located at a certain distance from directly below the base station, and the reception power of the perch channel measured just below the base station, reception Since it is assumed that no sharp change in quality will occur, the mobile station proceeds to step S806.
In, the measurement cycle T is changed to a longer interval Tlong.
If the perch channel propagation loss L is smaller than the threshold Lhigh, the mobile station proceeds to step S807, and changes the measurement cycle T to the standard interval Tnormal. The mobile station determines in step S808
, A timer is issued based on the measurement period T determined in the above-described step, and when the timer expires, the perch channel is measured again.

(Channel Measurement Control 7) FIG. 9 is a flowchart showing an example of processing in the case where the measurement period is determined based on the fluctuation amount of the propagation loss of the perch channel measured by the mobile station and channel measurement is performed. Here, the fluctuation amount of the propagation loss is an absolute value of a difference between the propagation loss measured (calculated) this time and the propagation loss measured last time. Step S901
In, the communicating mobile station measures the perch channel and receives the transmission power information of the perch channel that is being broadcast. In step S902, the propagation loss L is calculated based on the measured perch channel reception power P and the received perch channel transmission power information. In step S903, the variation Cl of the propagation loss is calculated from the absolute value of the difference between the measured propagation loss L of the perch channel and the previously measured propagation loss Llast.

As the variation Cl of the propagation loss, similar to the variation Cp of the received power, for example, the maximum variation of the propagation loss of the perch channel of the base station (channel) with which the mobile station is currently communicating is used. It is conceivable to use a value or the like.

In step S904, the calculated amount Cl of the propagation loss and the threshold value Clbig of the perch channel propagation loss fluctuation for shortening the measurement period preset in the mobile station.
Compare with If the fluctuation amount Cl of the perch channel propagation loss is larger than the threshold Clbig, the mobile station is assumed to be in an area where the propagation loss changes abruptly. Therefore, the mobile station shortens the measurement period T in step S905. Change to interval Tshort. If the fluctuation amount Cl of the perch channel propagation loss is smaller than the threshold Clbig, the mobile station proceeds to step S
Proceeding to 906, in step S906, the calculated perch channel propagation loss variation Cl is compared with a perch channel propagation loss threshold Clsmall for measurement period extension preset in the mobile station. If the fluctuation amount Cl of the perch channel propagation loss is smaller than the threshold Clsmall, it is assumed that the mobile station exists in a stable area where the propagation loss does not change abruptly. Therefore, the mobile station sets the measurement period T in step S907. Change to a longer interval Tlong. If the fluctuation amount Cl of the perch channel propagation loss is larger than the threshold value Clsmall, the mobile station proceeds to step S908, and executes the measurement cycle T
To the standard interval Tnormal. The mobile station performs step S9.
09, the measurement period T determined in the above-described steps
, A timer is issued, and when the timer expires, the perch channel is measured again.

(Channel Measurement Control 8) FIG. 10 is a flowchart showing an example of processing in the case where the measurement period is determined based on the propagation delay of the perch channel measured by the mobile station and channel measurement is performed. In step S1001, the communicating mobile station measures the perch channel and receives the propagation delay information of the broadcast perch channel. In step S1002, the measured perch channel propagation delay D is compared with the perch channel propagation delay threshold Dshort for measurement period shortening preset in the mobile station.

The propagation delay D is, for example, the time required for the base station to transmit some signal to the mobile station and for the mobile station to respond to the signal, and for the base station to transmit a signal and receive a response. The time can be measured to be propagation delay information and transmitted to the mobile station. Also, for example, the time at which the base station transmitted the perch channel, independently or transmitted to the mobile station as propagation delay information included in the perch channel, and the time at which the mobile station received the transmission time and the perch channel The propagation delay can be obtained from

As the propagation delay D, similarly to the reception power P,
For example, it is conceivable to use the maximum value of the propagation delay of the perch channel of the base station (channel) with which the mobile station is currently communicating.

The perch channel propagation delay D is equal to the threshold Dshort
If it is smaller, it is assumed that the mobile station is immediately below the base station, and it is assumed that a sudden change in the reception power and reception quality of the perch channel being measured occurs. Change the cycle T to a shorter interval Tshort. If the perch channel propagation delay D is greater than the threshold Dshort, the mobile station proceeds to step S100
In step S1004, the measured perch channel propagation delay D and the perch channel propagation delay threshold Dlon for measurement period extension set in the mobile station are set in advance.
Compare with g. Perch channel propagation delay D is threshold Dlon
If it is larger than g, it is presumed that the mobile station is located at a certain distance from directly below the base station, and there is no rapid change in the reception power and reception quality of the measured perch channel just below the base station. Therefore, in step S1005, the mobile station changes the measurement period T to a longer interval Tlong. Perch channel propagation delay D
Is smaller than the threshold Dlong, the mobile station proceeds to step S10
In step 06, the measurement cycle T is changed to the standard interval Tnormal.
In step S1007, the mobile station issues a timer based on the measurement period T determined in the above step, and when the timer expires, measures the perch channel again.

(Channel Measurement Control 9) FIG. 11 is a flowchart showing an example of processing in a case where the measurement period is determined based on the fluctuation amount of the propagation delay of the perch channel measured by the mobile station and channel measurement is performed. Here, the variation amount of the propagation delay is an absolute value of a difference between the propagation delay measured this time and the propagation delay measured last time. In step S1101, the communicating mobile station measures the perch channel and receives the propagation delay information of the broadcast perch channel. In step S1102, the received propagation delay D of the perch channel and the previously measured propagation delay Dlast
The variation Cd of the propagation delay is calculated from the absolute value of the difference.

As the fluctuation amount Cd of the propagation loss, similarly to the fluctuation amount Cp of the reception power, for example, the maximum value of the fluctuation amount of the propagation delay of the perch channel of the base station (channel) with which the mobile station is currently communicating. It is conceivable to use such as.

In step S1103, the calculated propagation delay fluctuation amount Cd and the perch channel propagation delay fluctuation amount threshold Cdbi preset in the mobile station for shortening the measurement period are set.
Compare with g. Perturbation channel propagation delay variation Cd
Is larger than the threshold value Cdbig, it is assumed that the mobile station exists in an area where the propagation delay changes abruptly. Therefore, the mobile station changes the measurement cycle T to a shorter interval Tshort in step S1104. If the variation amount Cd of the perch channel propagation delay is smaller than the threshold value Cdbig, the mobile station proceeds to step S1105, and in step S1105, the calculated variation amount Cd of the perch channel propagation delay and a measurement preset in the mobile station. This is compared with the perch channel propagation delay threshold Cdsmall for period extension. If the variation amount Cd of the perch channel propagation delay is smaller than the threshold value Cdsmall, the mobile station is assumed to be in a stable area where the propagation delay does not change abruptly.
At 6, the measurement cycle T is changed to a longer interval Tlong. Perch channel propagation delay variation Cd is threshold Cdsmal
If it is larger than 1, the mobile station proceeds to step S1107, and changes the measurement period T to the standard interval Tnormal. In step S1108, the mobile station issues a timer based on the measurement period T determined in the above step, and when the timer expires, measures the perch channel again.

(Channel Measurement Control 10) FIG. 12 is a flowchart showing an example of processing in a case where a measurement cycle is determined based on the number of perch channels, reception power, and reception quality measured by the mobile station, and channel measurement is performed. . Step S
At 1201, a communicating mobile station measures a perch channel. In step S1202, the measured number N of perch channels is compared with a permissible channel number threshold Nlarge for measurement cycle shortening preset in the mobile station. If the number N of the perch channels exceeds the threshold Nlarge, it can be estimated that the mobile station is in a zone where many zones are densely located in a short distance such as directly below the base station, and the reception power of the perch channel being measured, Since a sudden change in reception quality is expected to occur, the mobile station performs step S
At 1203, the measurement cycle T is changed to a shorter interval Tshort. If the number N of perch channels is less than the threshold Nlarge, the mobile station proceeds to step S1204, and proceeds to step S1204.
At 1204, the measured perch channel reception power P and the measurement period extension reception power threshold Pbig preset in the mobile station are preset to the measured perch channel reception quality Q and the mobile station. The reception quality threshold value Qbig for measurement period extension is compared with each other. Received power P
Exceeds the threshold value Pbig, and the reception quality Q exceeds the threshold value Qbig, the mobile station is present at a relatively distant point from the base station, and the received power of the perch channel being measured, a sudden change in the reception quality Since it is assumed that this will not occur, the mobile station changes the measurement period T to a longer interval Tlong in step S1205. If the reception power P exceeds the threshold Pbig and the reception quality Q does not satisfy the condition of exceeding the threshold Qbig, the mobile station proceeds to step S1206, where the measured reception power P of the perch channel and the mobile station are preset. The measurement cycle shortening reception power threshold Psmall, the measured perch channel reception quality Q and the measurement cycle shortening reception quality threshold Qsmall preset in the mobile station,
Compare each. Received power P falls below threshold Psmall,
Or, if the reception quality Q is lower than the threshold Qsmall, the mobile station is located far away from the base station, and currently the mobile station is receiving sufficient power, but may be in an insufficient state in the near future. Assuming that the mobile station performs step S120
At 7, the measurement cycle T is changed to a shorter interval Tshort. Received power P is below threshold Psmall or received quality Q
Does not satisfy the condition of being less than the threshold value Qsmall, the mobile station proceeds to step S1208 and sets the measurement period T to the standard interval Tnorm.
Change to al. The mobile station determines in step S1209
A timer is issued based on the measurement cycle T determined in the above-described steps, and when the timer expires, the perch channel is measured again.

(Channel Measurement Control 11) FIG. 13 is a flow chart showing an example of processing in a case where a measurement cycle is determined based on the number of perch channels measured by the mobile station, a propagation loss and a propagation delay, and channel measurement is performed. . Step S
In 1301, a mobile station in communication measures a perch channel and receives broadcast power information and propagation delay information of the perch channel that is being broadcast. In step S1302, a propagation loss L is calculated based on the measured perch channel reception power P and the received perch channel transmission power information. In step S1303, the measured number N of the perch channels is compared with a permutation channel number threshold Nlarge for measurement cycle shortening preset in the mobile station. The number N of perch channels is the threshold Nla
If the rge exceeds rge, it can be inferred that the mobile station is in a zone where many zones are densely located in a short distance, such as directly below the base station, and the sudden change in the propagation loss and propagation delay of the measured perch channel Since it is assumed to occur, the mobile station changes the measurement cycle T to a shorter interval Tshort in step S1304. The number N of perch channels is the threshold Nla
If it is less than rge, the mobile station proceeds to step S1305. In step S1305, the measured perch channel L and the measured perch channel propagation loss threshold Lsmall preset in the mobile station are compared with the measured perch. The propagation delay D of the channel is compared with the propagation delay threshold Dshort for extending the measurement period, which is preset in the mobile station. If the propagation loss L is less than the threshold Lsmall and the propagation delay D is less than the threshold Dshort, the mobile station is relatively far from the base station, and the received power of the perch channel being measured, the sharpness of the received quality Since it is assumed that no significant change occurs, the mobile station changes the measurement period T to a longer interval Tlong in step S1306. Propagation loss L is below threshold Lsmall, and propagation delay D is threshold Dshort
If the condition is not satisfied, the mobile station proceeds to step S1.
Proceeding to 307, the measured propagation loss L of the perch channel
And the propagation loss threshold Lbig for measurement period shortening preset in the mobile station, and the measured propagation delay of the perch channel.
D is compared with a propagation delay threshold Dlong for measurement period shortening preset in the mobile station. If the propagation loss L exceeds the threshold Lbig, or the propagation delay D exceeds the threshold Dlong, the mobile station is located far from the base station, and currently the mobile station is receiving sufficient power, but in the near future Since it is assumed that the state may be insufficient, the mobile station sets the measurement period T to a shorter interval T in step S1308.
Change to short. If the propagation loss L exceeds the threshold Lbig or the propagation delay D does not satisfy the condition exceeding the threshold Dlong, the mobile station proceeds to step S1309 and changes the measurement period T to the standard interval Tnormal. The mobile station performs step S13.
At 10, the measurement period T determined in the above steps
, A timer is issued, and when the timer expires, the perch channel is measured again.

(Channel Measurement Control 12) FIG. 14 shows a process for determining a measurement cycle based on the number of perch channels, reception power, reception quality, propagation loss and propagation delay measured by the mobile station, and performing channel measurement. It is a flowchart which shows an example. In step S1401, the communicating mobile station measures the perch channel and receives the transmission power information and the propagation delay information of the perch channel that has been broadcast. In step S1402, the propagation loss L is calculated based on the measured perch channel reception power P and the received perch channel transmission power information. In step S1403, the measured number N of perch channels is compared with a permissible channel number threshold Nlarge for measurement cycle shortening preset in the mobile station. If the number N of the perch channels exceeds the threshold Nlarge, it can be estimated that the mobile station is in a zone where a number of zones are densely located in a short distance such as directly below the base station, and the propagation loss of the perch channel being measured, Since it is assumed that a rapid change in the propagation delay occurs, the mobile station determines in step S1404
Change the measurement cycle T to a shorter interval Tshort.

If the number N of perch channels is smaller than the threshold value Nlarge, the mobile station proceeds to step S1405. In step S1405, the measured reception power P of the perch channel and the reception period extension preset in the mobile station are set. The power threshold value Pbig is compared with the measured reception quality Q of the perch channel and the measurement period extension reception quality threshold value Qbig preset in the mobile station. Receive power
When P exceeds the threshold value Pbig and the reception quality Q exceeds the threshold value Qbig, the mobile station is located relatively far from the base station, and the received power of the perch channel being measured is rapidly changed. Is assumed not to occur, the mobile station changes the measurement period T to a longer interval Tlong in step S1406. If the reception power P exceeds the threshold Pbig and the reception quality Q does not satisfy the condition of exceeding the threshold Qbig, the mobile station proceeds to step S1407, and the measured reception power P of the perch channel and the mobile station are preset. The measurement cycle shortening reception power threshold Psmall, the measured perch channel reception quality Q and the measurement cycle shortening reception quality threshold Qsmall preset in the mobile station,
Compare each. Received power P falls below threshold Psmall,
Or, if the reception quality Q is lower than the threshold Qsmall, the mobile station is located far away from the base station, and currently the mobile station is receiving sufficient power, but may be in an insufficient state in the near future. Since it is assumed, the mobile station determines in step S140
At 8, the measurement cycle T is changed to a shorter interval Tshort.

If the received power P is less than the threshold value Psmall or the reception quality Q does not satisfy the condition of being less than the threshold value Qsmall, the mobile station proceeds to step S1409 and sets the measured perch channel propagation loss L and the mobile station in advance. The measured propagation delay threshold Lsmall for extension of the measurement period is compared with the measured propagation delay D of the perch channel and the propagation delay threshold Dshort for extension of the measurement period preset in the mobile station. If the propagation loss L is less than the threshold Lsmall and the propagation delay D is less than the threshold Dshort, the mobile station is relatively far from the base station, and the received power of the perch channel being measured, the sharpness of the received quality Since no change is expected to occur, the mobile station determines in step S1410
In, the measurement cycle T is changed to a longer interval Tlong.
Propagation loss L is below threshold Lsmall, and propagation delay D is threshold
If the condition of less than Dshort is not satisfied, the mobile station proceeds to step S1411, and calculates the measured perch channel propagation loss L and the measurement period shortening propagation loss threshold Lbig preset in the mobile station by the measured perch. The propagation delay D of the channel is compared with a propagation delay threshold Dlong for shortening the measurement period, which is preset in the mobile station. The propagation loss L exceeds the threshold Lbig, or the propagation delay D is the threshold Dlong
If the mobile station is located far away from the base station and the mobile station is currently receiving sufficient power, it is assumed that the mobile station will be in an insufficient state in the near future,
In step S1412, the mobile station changes the measurement cycle T to a shorter interval Tshort.

If the propagation loss L does not exceed the threshold Lbig or the propagation delay D does not satisfy the condition of exceeding the threshold Dlong, the mobile station proceeds to step S1413 and changes the measurement period T to the standard interval Tnormal. In step S1414, the mobile station issues a timer based on the measurement period T determined in the above step, and when the timer expires, measures the perch channel again.

In FIG. 14, after the processing of group B (processing of steps S1409 to S1412) is performed, the processing of group A (steps S1405 to S140) is performed.
8) may be performed.

[0084]

As described above, according to the present invention, an appropriate measurement period can be determined, and channel measurement can be performed at the measurement period. Thereby, for example, the DHO followability can be improved and communication can be stabilized. Also,
Battery consumption can be reduced.

[Brief description of the drawings]

FIG. 1 is a flowchart illustrating an example of a conventional channel measurement process.

FIG. 2 is a diagram illustrating a configuration example of a mobile station according to the embodiment of the present invention.

FIG. 3 is a flowchart illustrating a processing example when a measurement period is determined based on the number of perch channels measured by a mobile station and channel measurement is performed.

FIG. 4 is a flowchart illustrating a processing example in a case where a measurement period is determined based on reception power of a perch channel measured by a mobile station and channel measurement is performed.

FIG. 5 is a flowchart illustrating a processing example in a case where a measurement period is determined based on a variation amount of received power of a perch channel measured by a mobile station and channel measurement is performed.

FIG. 6 is a flowchart illustrating a processing example in a case where a measurement period is determined based on reception quality of a perch channel measured by a mobile station and channel measurement is performed.

FIG. 7 is a flowchart illustrating an example of processing in a case where a measurement period is determined based on a fluctuation amount of reception quality of a perch channel measured by a mobile station and channel measurement is performed.

FIG. 8 is a flowchart illustrating an example of processing when a measurement period is determined based on a perch channel propagation loss measured by a mobile station and channel measurement is performed.

FIG. 9 is a flowchart illustrating a processing example in a case where a measurement period is determined based on a variation amount of a propagation loss of a perch channel measured by a mobile station and channel measurement is performed.

FIG. 10 is a flowchart illustrating a processing example in a case where a measurement period is determined based on a perch channel propagation delay measured by a mobile station and channel measurement is performed.

FIG. 11 is a flowchart illustrating a processing example in a case where a measurement period is determined based on a variation amount of a propagation delay of a perch channel measured by a mobile station and channel measurement is performed.

FIG. 12 is a flowchart illustrating a processing example in a case where a measurement period is determined based on the number of perch channels, reception power, and reception quality measured by a mobile station, and channel measurement is performed.

FIG. 13 is a flowchart illustrating a processing example in a case where a measurement period is determined based on the number of perch channels, propagation loss, and propagation delay measured by a mobile station, and channel measurement is performed.

FIG. 14 is a flowchart illustrating a processing example in a case where a measurement period is determined based on the number of perch channels, reception power, reception quality, propagation loss, and propagation delay measured by a mobile station, and channel measurement is performed.

[Explanation of symbols]

 Reference Signs List 200 Mobile station 201 Control unit 202 Radio unit 203 Timer control unit 204 Perch channel measurement control unit 205 Measurement unit

Continuing on the front page (72) Inventor Shinsuke Ogawa 2-10-1, Toranomon, Minato-ku, Tokyo Inside NTT Mobile Communication Network Corporation (72) Inventor Hisashi Takeshita 2--10 Toranomon, Minato-ku, Tokyo No. 1 Inside NTT Mobile Communication Network Co., Ltd. (72) Inventor Shogo Ito 2-10-1, Toranomon, Minato-ku, Tokyo F-Term within NTT Mobile Communication Network Co., Ltd. 5K067 AA23 AA43 DD44 DD45 EE02 EE10 EE24 JJ15 JJ35 JJ39

Claims (31)

[Claims] 1. A channel measurement control method in a mobile station for detecting one or more channels transmitted by one or more base stations and making a communication request to one or more base stations, comprising: a measurement step of measuring the channels; A control step of determining a measurement cycle in the measurement step based on the state of the channel measured in the measurement step, wherein the measurement step measures the channel in the measurement cycle determined by the control step. Channel measurement control method to perform. 2. The channel measurement control method according to claim 1, wherein the control step determines a measurement cycle in the measurement step based on the number of channels measured in the measurement step. Measurement control method. 3. The channel measurement control method according to claim 1, wherein the control step determines a measurement cycle in the measurement step based on reception power of a channel measured in the measurement step. Channel measurement control method. 4. The channel measurement control method according to claim 1, wherein the control step determines a measurement cycle in the measurement step based on a variation in received power of the channel measured in the measurement step. Characteristic channel measurement control method. 5. The channel measurement control method according to claim 1, wherein the control step determines a measurement cycle in the measurement step based on reception quality of a channel measured in the measurement step. Channel measurement control method. 6. The channel measurement control method according to claim 1, wherein the control step determines a measurement cycle in the measurement step based on a variation in reception quality of the channel measured in the measurement step. Characteristic channel measurement control method. 7. The channel measurement control method according to claim 1, wherein the control step determines a measurement cycle in the measurement step based on a propagation loss of the channel measured in the measurement step. Channel measurement control method. 8. The channel measurement control method according to claim 7, wherein the control step shortens a measurement cycle when the propagation loss is small, and lengthens the measurement cycle when the propagation loss is large. A channel measurement control method. 9. The channel measurement control method according to claim 1, wherein the control step determines a measurement cycle in the measurement step based on a variation amount of a propagation loss of the channel measured in the measurement step. Characteristic channel measurement control method. 10. The channel measurement control method according to claim 1, wherein the control step determines a measurement cycle in the measurement step based on a propagation delay of a channel measured in the measurement step. Channel measurement control method. 11. The channel measurement control method according to claim 10, wherein the control step shortens a measurement cycle when the propagation delay is small, and lengthens the measurement cycle when the propagation delay is large. A channel measurement control method. 12. The channel measurement control method according to claim 1, wherein the control step determines a measurement period in the measurement step based on a variation amount of a propagation delay of the channel measured in the measurement step. Characteristic channel measurement control method. 13. The channel measurement control method according to claim 1, wherein the control step determines a measurement cycle in the measurement step based on the number of channels, reception power, and reception quality measured in the measurement step. A channel measurement control method, characterized in that: 14. The channel measurement control method according to claim 1, wherein said control step determines a measurement period in said measurement step based on the number of channels, propagation loss, and propagation delay measured in said measurement step. A channel measurement control method, characterized in that: 15. The channel measurement control method according to claim 1, wherein the control step is performed based on the number of channels, reception power, reception quality, propagation loss, and propagation delay measured in the measurement step. A channel measurement control method, characterized in that a measurement period is determined in the above. 16. A mobile station that detects one or more channels transmitted by one or more base stations and issues a communication request to one or more base stations, comprising: a measuring unit that measures the channel; And a control means for determining a measurement cycle by the measurement means based on the measured state of the channel, wherein the measurement means measures the channel at the measurement cycle determined by the control means. 17. The mobile station according to claim 16, wherein:
The mobile station, wherein the control means determines a measurement cycle in the measurement means based on the number of channels measured by the measurement means. 18. The mobile station according to claim 16, wherein:
The mobile station, wherein the control means determines a measurement cycle in the measurement means based on the reception power of the channel measured by the measurement means. 19. The mobile station according to claim 16, wherein:
A mobile station, wherein the control means determines a measurement cycle in the measurement means based on a variation in received power of a channel measured by the measurement means. 20. The mobile station according to claim 16, wherein:
A mobile station, wherein the control means determines a measurement cycle in the measurement means based on reception quality of a channel measured by the measurement means. 21. The mobile station according to claim 16, wherein
A mobile station, wherein the control means determines a measurement cycle in the measurement means based on a variation in reception quality of a channel measured by the measurement means. 22. The mobile station according to claim 16, wherein
The mobile station, wherein the control means determines a measurement cycle in the measurement means based on a channel propagation loss measured by the measurement means. 23. The mobile station according to claim 22, wherein
A mobile station, wherein the control means shortens the measurement cycle when the propagation loss is small, and lengthens the measurement cycle when the propagation loss is large. 24. The mobile station according to claim 16, wherein
A mobile station, wherein the control means determines a measurement period in the measurement means based on a variation in channel propagation loss measured by the measurement means. 25. The mobile station according to claim 16, wherein
A mobile station, wherein the control means determines a measurement cycle in the measurement means based on a propagation delay of a channel measured by the measurement means. 26. The mobile station according to claim 25, wherein:
The mobile station, wherein the control means shortens the measurement cycle when the propagation delay is small, and lengthens the measurement cycle when the propagation delay is large. 27. The mobile station according to claim 16, wherein
A mobile station, wherein the control means determines a measurement cycle in the measurement means based on a variation amount of a propagation delay of a channel measured by the measurement means. 28. The mobile station according to claim 16, wherein
A mobile station, wherein the control means determines a measurement cycle in the measurement means based on the number of channels, reception power, and reception quality measured by the measurement means. 29. The mobile station according to claim 16, wherein
A mobile station, wherein the control means determines a measurement cycle in the measurement means based on the number of channels, propagation loss, and propagation delay measured by the measurement means. 30. The mobile station according to claim 16, wherein:
A mobile station, wherein the control unit determines a measurement cycle in the measurement unit based on the number of channels, reception power, reception quality, propagation loss, and propagation delay measured by the measurement unit. 31. A mobile communication system comprising: the mobile station according to claim 16; and a base station that communicates with the mobile station.