JP4992593B2 - Mobile radio terminal device - Google Patents

Description

  The present invention relates to a mobile radio terminal used in a mobile communication system such as a mobile phone system.

  As is well known, in a mobile communication system such as a mobile phone system, for example, a plurality of base stations each form a radio zone, and the mobile radio terminal apparatus measures the reception quality of a pilot signal transmitted from the base station. Then, location registration is performed through a base station with good reception quality, and incoming call waiting is performed (see, for example, Non-Patent Document 1 and Non-Patent Document 2).

However, when a mobile radio terminal device is located in a so-called fringe area such as a radio zone boundary, the reception quality varies greatly, and location registration may occur frequently. For example, when the user's home is in the fringe area, location registration frequently occurs regularly, and the mobile radio terminal device has a problem of wasting the battery.
3GPP TS 25.331 V6.10.0 (2006-06) Technical Specification 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Radio Resource Control (RRC); Protocol Specification (Release 6) 3GPP TS 25.304 V5.9.0 (2005-09) Technical Specification 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; User Equipment (UE) procedures in idle mode and procedures for cell reselection in connected mode (Release 5)

In the conventional mobile radio terminal apparatus, if the operating environment frequently used by the user is a fringe area, the location registration process with respect to the base station occurs frequently and the battery is wasted.
The present invention has been made to solve the above problem, and even if the user uses it in the fringe area, it accurately determines the necessity of the location registration process and suppresses battery waste due to unnecessary location registration processing. An object of the present invention is to provide a mobile radio terminal device capable of performing the above.

In order to achieve the above object, the present invention relates to a quality detection means for detecting reception quality and occurrence of handover in a mobile radio terminal apparatus that performs radio communication by selecting a plurality of base stations accommodated in a mobile communication network. and frequency detecting means for detecting the frequency, at a cycle corresponding to the frequency of said frequency detecting unit detects, comparing means for comparing the reception quality of the base station which finished the location registration, the reception quality of the other base station , according to the comparison result of the comparison means, comprising a registration means for performing a location registration, the comparing means, for comparing a preset time, the reception quality of the base station which finished the location registration, the other base The registration means compares the reception quality of other base stations with the reception quality of the base station that has completed the location registration during the comparison time based on the comparison result of the comparison means. Other than the above, And it carries out location registration to the base station.

  As described above, in the present invention, the reception quality of the base station whose location registration has been completed is compared with the reception quality of other base stations at a cycle according to the frequency of occurrence of handover, and according to the comparison result Location registration is performed.

  Therefore, according to the present invention, for example, even when the user uses the fringe area, it is possible to determine the necessity of accurate location registration processing according to the frequency of occurrence of handover, and to suppress battery waste due to unnecessary location registration processing. A possible mobile radio terminal device can be provided.

  Hereinafter, a mobile communication system according to an embodiment of the present invention will be described with reference to the drawings. The mobile communication system includes a base station accommodated in a mobile communication network and a mobile station that performs radio communication with the base station. In the following description, a case where an OFDM (Orthogonal Frequency Division Multiplexing) scheme is adopted as a modulation scheme for communication between a base station and a mobile station will be described as an example.

  First, the configuration of the mobile station in the wireless communication system according to the first embodiment of the present invention will be described. FIG. 1 mainly shows the configuration of the downlink reception system of the above system provided in this mobile station.

  As shown in FIG. 1, the mobile station includes a control unit 100, a radio reception unit 101, a GI (Guard Interval) removal unit 102, an FFT (Fast Fourier Transform) unit 103, a signal separation unit 104, and a quality measurement. Unit 105, control channel demodulation unit 106, orthogonal code multiplication unit 107, depreciation unit 108, demodulation unit 109, channel deinterleaver 110, channel decoder 111, storage unit 112, and transmission system 113 And.

The radio receiving unit 101 receives a radio signal transmitted from the base station, removes noise outside the desired band from the received signal, and converts the signal that has passed through the filter into a baseband digital signal. An AD converter.
The GI removal unit 102 removes the guard interval from the baseband digital signal output from the wireless reception unit 101.

  The FFT unit 103 performs fast Fourier transform on the digital signal from which the guard interval has been removed by the GI removal unit 102 and converts the signal from the time domain to the frequency domain, thereby dividing the signal into signals for each subcarrier.

  The signal separation unit 104 separates the signal divided for each subcarrier by the FFT unit 103 into a phase reference signal, a control signal, a data signal, and the like, and outputs the separated signals to corresponding modules. In this example, the phase reference signal is output to the quality measurement unit 105 and the demodulation unit 109, the control signal is output to the control channel demodulation unit 106, and the data signal is output to the orthogonal code multiplication unit 107.

  The quality measurement unit 105 operates in accordance with an instruction from the control unit 100, and obtains a signal received from each base station by taking a cross-correlation between the scrambling pattern assigned to each base station and the received phase reference signal. Measure the power level or power density. Then, the quality measurement unit 105 obtains an interference level from the reception power level of each base station and the reception power level ratio of other base stations from the measurement result for each base station. The quality measuring unit 105 also determines the interference generated between sectors by distinguishing the received signals of each sector formed by the base station by the scrambling pattern even in the same base station.

  The control channel demodulation unit 106 demodulates the control signal given from the signal separation unit 104, extracts control information regarding the physical layer, and outputs this control information to the control unit 100. The control information includes MCS information indicating a transmission format sent from the base station and incoming call notification information for notifying the occurrence of an incoming call addressed to the mobile station.

  The orthogonal code multiplication unit 107 multiplies the data signal by the complex conjugate of the orthogonal code corresponding to the parameter N instructed from the control unit 100, cancels the signal component from the other base station, and obtains the multiplication result. Output. When the parameter N = 1, the data signal is output as it is without performing the complex conjugate multiplication of the orthogonal code on the data signal.

  The depreciation unit 108 cumulatively adds the multiplication results of the orthogonal code multiplication unit 107 by the parameter N instructed from the control unit 100, and outputs the result as one data. Note that when the parameter N = 1, the multiplication result is not accumulated and output as it is.

  Demodulation section 109 obtains a channel estimated value of the subcarrier frequency from the phase reference signal, uses this to channel-equalize the output of depreciation section 108, and obtains the equivalent result from the demodulation scheme instructed by control section 100. By demodulating the data, the bit string constituting the data signal is reproduced.

Channel deinterleaver 110 performs channel deinterleaving on the bit string output from demodulation section 109 based on the interleave pattern instructed from control section 100.
The channel decoder 111 performs channel decoding on the bit string output from the channel deinterleaver 110 at the coding rate R instructed from the control unit 100, and reproduces transmission data.

  The storage unit 112 stores a control program and control data of the control unit 100. For example, the storage unit 112 stores a transmission format table as control data. The transmission format table associates MCS information for identifying a transmission format with information such as a modulation scheme M, a coding rate R, a repetition factor, and a parameter N for determining orthogonalization.

The storage unit 112 also stores a handover table that stores the time of occurrence of handover. Further, the storage unit 112 stores a measurement cycle table in which the handover parameter L and the measurement cycle _Tn are associated with each other as illustrated in FIG. T> T ₁ > T ₂ > T ₃ >...> 0, and T is, for example, 3GPP TS 25.331 V6.10.0 (2006-06) Technical Specification 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Radio Resource Control (RRC): A normal measurement cycle defined by Protocol Specification (Release 6).

The control unit 100 generates control information indicating the interference level obtained by the quality measuring unit 105 and transmits the control information to the base station through the transmission system 113.
Further, the control unit 100 detects MCS information from the control information extracted by the control channel demodulation unit 106, and determines that the transmission format used by the base station for transmission to the mobile station is the transmission format indicated by the MCS information. recognize. Then, the control unit 100 refers to the transmission format table stored in the storage unit 112 and controls the respective units of the mobile station by using parameters corresponding to the MCS information so that the information transmitted from the base station can be received. To do.

  The control unit 100 also has a function of measuring time, and based on the handover table, the measurement cycle table, the handover parameter L, and the power level or power density of each base station measured by the quality measurement unit 105. Thus, a function for determining the necessity of handover and executing handover according to the determination result is provided.

  Next, the operation of the mobile station having the above configuration will be described. Here, an operation related to determination and execution of handover will be described in particular. FIG. 3 is a flowchart for explaining this operation, and is performed by the control unit 100. The control unit 100 reads the control program from the storage unit 112 and executes it. The process shown in FIG. 3 is repeated when the power of the base station is turned on until the power is turned off. When the power is turned on, the handover parameter L is set to “1” as an initial value. Thereafter, the value updated in the process shown in FIG. 3 is held until the power is turned off.

  First, in step 3a, the control unit 100 controls the operation of each part of the reception system to intermittently receive a signal transmitted from a base station (hereinafter referred to as a current base station) used for communication or waiting for an incoming call, The measurement unit 105 is caused to measure the received power level (or power density), and the process proceeds to step 3b. Thereby, each part of the receiving system receives a signal transmitted from a base station other than the current base station, and the quality measuring unit 105 measures the received power level based on the signal.

Control unit in step 3b 100, by receiving power level is measured to the quality measuring unit 105 in Step 3a to determine whether the threshold th ₁ below a preset, determines whether there is a need for handover To do. Here, when the received power level is equal to or lower than the threshold th ₁ , the process proceeds to step 3c, whereas when the received power level is higher than the threshold th ₁ , the process proceeds to step 3a.

  In step 3c, the control unit 100 controls the operation of each unit of the reception system and the quality measurement unit 105 again to measure the received power level for base stations other than the current base station. Thereby, each part of the receiving system receives a signal transmitted from a base station other than the current base station, and the quality measuring unit 105 measures the received power level based on the signal. And the control part 100 detects the candidate base station from which high received power is obtained based on the measurement result, and transfers to step 3d.

  In step 3d, the control unit 100 refers to the handover table stored in the storage unit 112, detects the number of handovers that occurred within a predetermined time in the past from the current time, that is, the occurrence frequency f of handover that occurred within the predetermined time, Control goes to step 3e.

Controller 100 in step 3e, the frequency f of the handover detected in step 3d is, by determining whether preset threshold value th ₂ less or more, determines whether a handover is frequently. Here, if the handover occurrence frequency f is less than the threshold th _2, the process proceeds to step 3f, whereas, handover frequency f is in the case of the threshold value th ₂ or more, the process proceeds to step 3A.

  In step 3f, the control unit 100 starts a timer and sets a preset time (for example, 3GPP TS 25.331 V6.10.0 (2006-06) Technical Specification 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Radio Resource Control (RRC ); Starts a countdown of the time specified in Protocol Specification (Release 6), 5.12 seconds), and proceeds to step 3g.

  In step 3g, the control unit 100 determines whether or not a period T × k that is k times the preset normal period (k = 0, 1, 2,...) Has arrived since the timer start in step 3f. Then, it is determined whether or not the timing of intermittent reception has arrived. Here, when the timing of intermittent reception has arrived, the process proceeds to step 3h. On the other hand, when the timing of intermittent reception has not arrived, the process proceeds to step 3g, and the arrival of intermittent reception timing again. Monitor.

  In step 3h, the control unit 100 controls the control channel demodulation unit 106 to receive the control signal transmitted from the current base station, and based on the demodulation result, the incoming call notification information indicating the arrival of the incoming call addressed to the mobile station. Check if there is any. Here, when incoming call notification information is detected, incoming call notification processing (not shown) is executed to notify the user of the incoming call.

  Further, in step 3h, following the reception of the control signal, the control unit 100 controls the operation of each unit of the reception system and the quality measurement unit 105 to measure the received power level for the current base station and the candidate base station. Thereby, each part of the receiving system receives signals transmitted from the current base station and the candidate base station, respectively, and the quality measuring unit 105 sets the received power level for the current base station and the candidate base station based on the signal. Measure and go to step 3i.

  In step 3i, the control unit 100 compares the received power level of the current base station measured by the quality measuring unit 105 in step 3h with the received power level of the candidate base station. When the received power level of the current base station is lower than the received power level of the candidate base station, the process proceeds to step 3j. On the other hand, when the received power level of the current base station is equal to or higher than the received power level of the candidate base station. Therefore, it is assumed that there is no need for handover, and the process is terminated.

  In step 3j, the control unit 100 determines whether or not a preset time has elapsed from the timer activation in step 3f by determining whether or not the timer activated in step 3f has timed out. Here, if the preset time has elapsed, the process proceeds to step 3p. On the other hand, if the preset time has not elapsed, the process returns to step 3g, and the received power level continues every measurement period T. Measure and compare

Controller 100 in step 3A refers to the measurement cycle table storage unit 112 stores, reads the measurement period T _n corresponding to the handover parameter L, the process proceeds to step 3k.

  In step 3k, the control unit 100 starts a timer and sets a preset time (for example, 3GPP TS 25.331 V6.10.0 (2006-06) Technical Specification 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Radio Resource Control (RRC ); Starts a countdown of the time specified in Protocol Specification (Release 6), 5.12 seconds), and proceeds to step 3l.

In step 31, the control unit 100 determines whether or not the normal period T _n × k (k = 0, 1, 2...) Set in advance has arrived since the timer start in step 3 k, thereby performing intermittent reception. It is determined whether or not timing has arrived. Here, when the timing of intermittent reception has arrived, the process proceeds to step 3m. On the other hand, when the timing of intermittent reception has not arrived, the process proceeds to step 3l, and the arrival of intermittent reception timing is again detected. Monitor.

  In step 3m, the control unit 100 controls the operation of each unit of the reception system and the quality measurement unit 105 to measure the received power level for the current base station and the candidate base station, and proceeds to step 3n. Thereby, each part of the receiving system receives signals transmitted from the current base station and the candidate base station, respectively, and the quality measuring unit 105 sets the received power level for the current base station and the candidate base station based on the signal. taking measurement.

In step 3m, when the current cycle T _n × k corresponds to a constant multiple of the normal cycle T, the control unit 100 controls the control channel demodulation unit 106 before measuring the received power level described above. Then, the control signal transmitted from the current base station is received, and based on the demodulation result, the presence / absence of incoming call notification information indicating the occurrence of an incoming call addressed to the mobile station is confirmed. Here, when incoming call notification information is detected, incoming call notification processing (not shown) is executed to notify the user of the incoming call.

  In step 3n, the control unit 100 compares the received power level of the current base station measured by the quality measuring unit 105 in step 3m with the received power level of the candidate base station. If the received power level of the current base station is less than the received power level of the candidate base station, the process proceeds to step 3o. On the other hand, if the received power level of the current base station is greater than or equal to the received power level of the candidate base station Therefore, it is assumed that there is no need for handover, and the process proceeds to step 3B.

In step 3o, the control unit 100 determines whether or not a preset time has elapsed from the timer activation in step 3k by determining whether or not the timer activated in step 3k has timed out. Here, in a case where a preset time has elapsed, the process proceeds to step 3p, whereas, if not elapsed time set in advance, the process returns to step 3l, subsequently, received power for each measurement cycle T _n Measure and compare levels.

In step 3B, the control unit 100 decreases the value of the handover parameter L by “1” and ends the process. Thus, when the process proceeds to the next step 3A, it will select one step longer period than the current measurement period T _n.

  In step 3p, the control unit 100 first controls the transmission system 113 to make a handover request to the candidate base station detected in step 3c, and then controls each unit of the reception system and the transmission system 113 to perform predetermined processing. Hand over to the candidate base station according to the procedure of And the control part 100 controls the transmission system 113, performs position registration through a candidate base station, and transfers to step 3q.

In step 3q, the control unit 100 records the time at which the handover in step 3p is completed in the handover table stored in the storage unit 112, and proceeds to step 3C.
In step 3C, the control unit 100 increases the value of the handover parameter L by “1” and ends the process. Thus, when the process proceeds to the next step 3A, it will select one step shorter period than the current measurement period T _n.

As described above, in the mobile station having the above configuration, in addition to the cell evaluation at the period T defined by the standard, the mobile station The candidate base stations are compared with each other so that the candidate base station can accurately and efficiently determine whether the candidate base station should perform handover.
That is, as shown in FIG. 4, when the handover does not occur frequently (f is less than the threshold th ₂ ), the comparison between the current base station and the candidate base station in the normal cycle T as shown in FIG. On the other hand, when handovers occur frequently (f is greater than or equal to the threshold th ₂ ), as shown in FIG. 4B, the current base station and the candidate are selected at a cycle T _n (<T) according to the handover parameter L. Compare with the base station.

Thus, when a handover occurs frequently, in order to determine the need for handover in a short cycle T _n than the normal period T definite by the standard, the reception received level of the candidate base station of the current base station power level It is easier to detect a state that is lower and not suitable as a standby base station, and when that state is detected (No in step 3n), standby is continued by the current base station without performing handover. .

  Therefore, according to the mobile station having the above configuration, even if the user uses it in the fringe area, it is possible to accurately determine the necessity of the location registration process, thereby suppressing battery waste due to unnecessary location registration processing. it can.

When handovers occur frequently (f is greater than or equal to the threshold th ₂ ), as shown in FIG. 4B, the current base station, the candidate base station, and the candidate base station have a cycle T _n (<T) according to the handover parameter L. The occurrence of an incoming call is detected only at a timing corresponding to a constant multiple of the normal period T. For this reason, the reception time for monitoring the occurrence of an incoming call can be suppressed, and an increase in power consumption accompanying the increase in the frequency of determination can be suppressed.

  Next explained is a mobile station of the radio communication system according to the second embodiment of the invention. The mobile station according to the second embodiment differs from the mobile station of the first embodiment described above in the control content of the control unit 100 and the information stored in the storage unit 112, but apparently has the same configuration. From the above, with reference to FIG. 1, the description will focus on the parts different from the mobile station of the first embodiment.

  The storage unit 112 stores a control program and control data of the control unit 100. For example, the storage unit 112 stores a transmission format table as control data. The transmission format table associates MCS information for identifying a transmission format with information such as a modulation scheme M, a coding rate R, a repetition factor, and a parameter N for determining orthogonalization.

The storage unit 112 also stores a handover table that stores the time of occurrence of handover. The storage unit 112 also stores a measurement cycle table in which the handover frequency f and the measurement cycle _Tn are associated with each other as shown in FIG. T> T ₁ > T ₂ > T ₃ >...> 0, and T is, for example, 3GPP TS 25.331 V6.10.0 (2006-06) Technical Specification 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Radio Resource Control (RRC): A normal measurement cycle defined by Protocol Specification (Release 6).

The control unit 100 generates control information indicating the interference level obtained by the quality measuring unit 105 and transmits the control information to the base station through the transmission system 113.
Further, the control unit 100 detects MCS information from the control information extracted by the control channel demodulation unit 106, and determines that the transmission format used by the base station for transmission to the mobile station is the transmission format indicated by the MCS information. recognize. Then, the control unit 100 refers to the transmission format table stored in the storage unit 112 and controls the respective units of the mobile station by using parameters corresponding to the MCS information so that the information transmitted from the base station can be received. To do.

  Further, the control unit 100 has a function of measuring time, and also requires handover based on the handover table, the measurement cycle table, and the power level or power density of each base station measured by the quality measurement unit 105. And a function of executing a handover according to the determination result.

  Next, the operation of the mobile station having the above configuration will be described. Here, an operation related to determination and execution of handover will be described in particular. FIG. 6 is a flowchart for explaining this operation, and is performed by the control unit 100. The control unit 100 reads the control program from the storage unit 112 and executes it. The process shown in FIG. 6 is repeatedly executed until the power is turned off when the base station is turned on.

  First, in step 6a, the control unit 100 controls the operation of each part of the reception system to intermittently receive a signal transmitted from a base station (hereinafter referred to as a current base station) used for communication or waiting for an incoming call. The measurement unit 105 is caused to measure the received power level (or power density), and the process proceeds to step 6b. Thereby, each part of the receiving system receives a signal transmitted from a base station other than the current base station, and the quality measuring unit 105 measures the received power level based on the signal.

Control unit in step 6b 100, by receiving power level is measured to the quality measurement unit 105 in step 6a to determine whether the threshold th ₁ below a preset, determines whether there is a need for handover To do. Here, when the received power level is less than the threshold th _1, the process proceeds to step 6c, whereas, if the received power level is greater than the threshold th _1, the process proceeds to step 6a.

  In step 6c, the control unit 100 again controls the operation of each unit of the reception system and the quality measurement unit 105 to measure the reception power level for base stations other than the current base station. Thereby, each part of the receiving system receives a signal transmitted from a base station other than the current base station, and the quality measuring unit 105 measures the received power level based on the signal. And the control part 100 detects the candidate base station from which high received power is obtained based on the measurement result, and transfers to step 6d.

  In step 6d, the control unit 100 refers to the handover table stored in the storage unit 112, detects the number of handovers that occurred within a predetermined time in the past from the current time, that is, the occurrence frequency f of handover that occurred within the predetermined time, Control goes to step 6e.

Controller 100 in step 6e refers to the measurement cycle table storage unit 112 stores, reads the measurement period T _n corresponding to the handover frequency f, the process proceeds to step 6f.
In step 6f, the control unit 100 starts a timer and sets a preset time (for example, 3GPP TS 25.331 V6.10.0 (2006-06) Technical Specification 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Radio Resource Control (RRC ); Starts a countdown of the time specified in Protocol Specification (Release 6), 5.12 seconds, and proceeds to Step 6g.

In step 6g, the control unit 100 determines whether or not a normal cycle T _n × k (k = 0, 1, 2,...) Set in advance has arrived since the timer start in step 6f. It is determined whether or not timing has arrived. Here, when the timing of intermittent reception has arrived, the process proceeds to step 6h. On the other hand, when the timing of intermittent reception has not arrived, the process proceeds to step 6g and the arrival of intermittent reception timing is again detected. Monitor.

  In step 6h, the control unit 100 controls the operation of each part of the reception system and the quality measurement unit 105 to measure the reception power level for the current base station and the candidate base station, and proceeds to step 6i. Thereby, each part of the receiving system receives signals transmitted from the current base station and the candidate base station, respectively, and the quality measuring unit 105 sets the received power level for the current base station and the candidate base station based on the signal. taking measurement.

In step 6h, when the current cycle T _n × k corresponds to a constant multiple of the normal cycle T, the control unit 100 controls the control channel demodulation unit 106 before measuring the received power level described above. Then, the control signal transmitted from the current base station is received, and based on the demodulation result, the presence / absence of incoming call notification information indicating the occurrence of an incoming call addressed to the mobile station is confirmed. Here, when incoming call notification information is detected, incoming call notification processing (not shown) is executed to notify the user of the incoming call.

  In step 6i, the control unit 100 compares the received power level of the current base station measured by the quality measuring unit 105 in step 6h with the received power level of the candidate base station. If the received power level of the current base station is less than the received power level of the candidate base station, the process proceeds to step 6j. On the other hand, if the received power level of the current base station is greater than or equal to the received power level of the candidate base station Therefore, it is assumed that there is no need for handover, and the process is terminated.

In step 6j, the control unit 100 determines whether or not a preset time has elapsed since the timer start in step 6f by determining whether or not the timer started in step 6f has timed out. Here, in a case where a preset time has elapsed, the process proceeds to step 6k, whereas, if not elapsed time set in advance, the process returns to step 6 g, subsequently, received power for each measurement cycle T _n Measure and compare levels.

In step 6k, the control unit 100 first controls the transmission system 113 to make a handover request to the candidate base station detected in step 6c, and then controls each unit of the reception system and the transmission system 113 to perform predetermined processing. Hand over to the candidate base station according to the procedure of And the control part 100 controls the transmission system 113, performs position registration through a candidate base station, and transfers to step 6l.
In step 61, the control unit 100 records the time at which the handover in step 6k is completed in the handover table stored in the storage unit 112, and ends the process.

As described above, the mobile station configured as described above compares the current base station with the candidate base station in a cycle according to the frequency of occurrence of handover in addition to the cell evaluation in the cycle T defined by the standard. It is determined accurately and efficiently whether a station is a base station that should perform a handover.
That is, as shown in FIG. 4, when handovers do not occur frequently (f is less than or equal to f ₁ ), the current base station and the candidate base station are compared with each other at a normal period T as shown in FIG. On the other hand, when handovers occur frequently (f is greater than f ₁ ), as shown in FIG. 4B, the current base station and the candidate bases with a cycle T _n (<T) according to the handover parameter L Compare with the station.

Thus, when a handover occurs frequently, in order to determine the need for handover in a short cycle T _n than the normal period T definite by the standard, the reception received level of the candidate base station of the current base station power level It is easy to detect a state that is lower and not suitable as a standby base station, and when that state is detected (No in step 6i), standby is continued by the current base station without performing handover. .

  Therefore, according to the mobile station having the above configuration, even if the user uses it in the fringe area, it is possible to accurately determine the necessity of the location registration process, thereby suppressing battery waste due to unnecessary location registration processing. it can.

When handovers occur frequently (f is greater than f ₁ ), as shown in FIG. 4B, the current base station and the candidate bases with a cycle T _n (<T) corresponding to the frequency of occurrence of handovers f. Comparison with the station is performed, but the occurrence of the incoming call is detected only at a timing corresponding to a constant multiple of the normal period T. For this reason, the reception time for monitoring the occurrence of an incoming call can be suppressed, and an increase in power consumption accompanying the increase in the frequency of determination can be suppressed.

  Next explained is a mobile station of the radio communication system according to the third embodiment of the invention. The mobile station according to the third embodiment is configured as shown in FIG. 7, and the mobile station of the first embodiment shown in FIG. 1, the control contents of the control unit 100, and the information stored in the storage unit 112 are stored. Are different from each other in that two antennas and an antenna switching unit 114 are provided. In the following description, the description will focus on parts different from the mobile station of the first embodiment shown in FIG.

The antenna switching unit 114 accommodates two antennas, selects one antenna in accordance with an instruction from the control unit 100, and uses it for reception.
The storage unit 112 stores a control program and control data of the control unit 100. For example, the storage unit 112 stores a transmission format table as control data. The transmission format table associates MCS information for identifying a transmission format with information such as a modulation scheme M, a coding rate R, a repetition factor, and a parameter N for determining orthogonalization.

The storage unit 112 also stores a handover table that stores the time of occurrence of handover. The storage unit 112 also stores a switching cycle table in which the handover parameter L and the antenna switching cycle (measurement cycle) _Tn are associated with each other as shown in FIG. T> T ₁ > T ₂ > T ₃ >...> 0, and T is, for example, 3GPP TS 25.331 V6.10.0 (2006-06) Technical Specification 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Radio Resource Control (RRC): A normal measurement cycle defined by Protocol Specification (Release 6).

The control unit 100 generates control information indicating the interference level obtained by the quality measuring unit 105 and transmits the control information to the base station through the transmission system 113.
Further, the control unit 100 detects MCS information from the control information extracted by the control channel demodulation unit 106, and determines that the transmission format used by the base station for transmission to the mobile station is the transmission format indicated by the MCS information. recognize. Then, the control unit 100 refers to the transmission format table stored in the storage unit 112 and controls the respective units of the mobile station by using parameters corresponding to the MCS information so that the information transmitted from the base station can be received. To do.

  The control unit 100 has a function of measuring time, and based on a handover table, a switching cycle table, a handover parameter L, and the power level or power density of each base station measured by the quality measurement unit 105. Thus, a function for determining the necessity of handover and executing handover according to the determination result is provided.

  Next, the operation of the mobile station having the above configuration will be described. Here, an operation related to determination and execution of handover will be described in particular. FIG. 9 is a flowchart for explaining this operation, and is performed by the control unit 100. The control unit 100 reads the control program from the storage unit 112 and executes it. The process shown in FIG. 9 is repeatedly executed until the power is turned off when the base station is turned on. When the power is turned on, the handover parameter L is set to “1” as an initial value. Thereafter, the value updated in the process shown in FIG. 9 is held until the power is turned off.

  First, in step 9a, the control unit 100 controls each part of the reception system to intermittently receive a signal transmitted from a base station (hereinafter referred to as a current base station) used for communication or waiting for an incoming call. The measurement unit 105 is caused to measure the received power level (or power density), and the process proceeds to step 9b. Thereby, each part of the receiving system receives a signal transmitted from a base station other than the current base station, and the quality measuring unit 105 measures the received power level based on the signal.

Control unit in step 9b 100, by receiving power level is measured to the quality measurement unit 105 in step 9a to determine whether the threshold th ₁ below a preset, determines whether there is a need for handover To do. Here, when the received power level is less than the threshold th _1, the process proceeds to step 9c, on the other hand, if the received power level is greater than the threshold th _1, the process proceeds to step 9a.

  In step 9c, the control unit 100 again controls the operation of each unit of the reception system and the quality measurement unit 105 to measure the reception power level for base stations other than the current base station. Thereby, each part of the receiving system receives a signal transmitted from a base station other than the current base station, and the quality measuring unit 105 measures the received power level based on the signal. And the control part 100 detects the candidate base station from which high received power is obtained based on the measurement result, and transfers to step 9d.

  In step 9d, the control unit 100 refers to the handover table stored in the storage unit 112, detects the number of handovers that have occurred within a predetermined time in the past from the current time, that is, the occurrence frequency f of handover that has occurred within the predetermined time, Control goes to step 9e.

Controller 100 in step 9e, the frequency f of the handover detected by the step 9d is, by determining whether preset threshold value th ₂ less or more, determines whether a handover is frequently. If the occurrence frequency f of the handover is less than the threshold th ₂ , the process proceeds to step 9 f, while if the occurrence frequency f of the handover is greater than or equal to the threshold th ₂ , the process proceeds to step 9 A.

  In step 9f, the control unit 100 starts a timer and sets a preset time (for example, 3GPP TS 25.331 V6.10.0 (2006-06) Technical Specification 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Radio Resource Control (RRC ); The countdown of the time specified in Protocol Specification (Release 6), 5.12 seconds) is started, and the process proceeds to Step 9g.

  In step 9g, the control unit 100 determines whether or not a period T × k that is k times the normal period set in advance (k = 0, 1, 2,...) Has arrived since the timer start in step 9f. Then, it is determined whether or not the timing of intermittent reception has arrived. Here, when the timing of intermittent reception has arrived, the process proceeds to step 9h. On the other hand, when the timing of intermittent reception has not arrived, the process proceeds to step 9g and the arrival of intermittent reception timing is again detected. Monitor.

  In step 9h, the control unit 100 controls the control channel demodulation unit 106 to receive the control signal transmitted from the current base station, and based on the demodulation result, incoming call notification information indicating the occurrence of an incoming call addressed to the mobile station. Check if there is any. Here, when incoming call notification information is detected, incoming call notification processing (not shown) is executed to notify the user of the incoming call.

  Further, in step 9h, following the reception of the control signal, the control unit 100 controls the operation of each unit of the reception system and the quality measurement unit 105 to measure the received power level for the current base station and the candidate base station. Thereby, each part of the receiving system receives signals transmitted from the current base station and the candidate base station, respectively, and the quality measuring unit 105 sets the received power level for the current base station and the candidate base station based on the signal. Measure and go to step 9i.

  In step 9i, the control unit 100 compares the received power level of the current base station measured by the quality measuring unit 105 in step 9h with the received power level of the candidate base station. If the received power level of the current base station is lower than the received power level of the candidate base station, the process proceeds to step 9j. On the other hand, if the received power level of the current base station is equal to or higher than the received power level of the candidate base station. Therefore, it is assumed that there is no need for handover, and the process is terminated.

  In step 9j, the control unit 100 determines whether or not a preset time has elapsed since the timer start in step 9f by determining whether or not the timer started in step 9f has timed out. Here, if the preset time has elapsed, the process proceeds to step 9p. On the other hand, if the preset time has not elapsed, the process returns to step 9g, and the received power level continues every measurement cycle T. Measure and compare

Controller 100 at step 9A refers to the switching period table storage unit 112 stores, switching corresponding to the handover parameter L (measured) reads the period T _n, the process proceeds to step 9k.

  In step 9k, the control unit 100 starts a timer and sets a preset time (for example, 3GPP TS 25.331 V6.10.0 (2006-06) Technical Specification 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Radio Resource Control (RRC ); Starts a countdown of the time specified in Protocol Specification (Release 6), 5.12 seconds, and proceeds to Step 9l.

In step 9l, the control unit 100 determines whether or not the normal period T _n × k (k = 0, 1, 2,...) Set in advance has arrived since the timer start in step 9k. It is determined whether or not timing has arrived. Here, when the timing of intermittent reception has arrived, the process proceeds to step 9D. On the other hand, when the timing of intermittent reception has not arrived, the process proceeds to step 9l and the arrival of intermittent reception timing is again detected. Monitor.

  In step 9D, the control unit 100 instructs the antenna switching unit 114 to switch the antenna, and proceeds to step 9m. As a result, the antenna switching unit 114 switches the antenna to be used from the currently used antenna to the unused antenna.

  In Step 9m, the control unit 100 controls the operation of each unit of the reception system and the quality measurement unit 105 to measure the reception power level for the current base station and the candidate base station, and proceeds to Step 9n. As a result, each part of the reception system receives signals transmitted from the current base station and the candidate base station through the antenna newly selected in step 9D, and the quality measurement unit 105 determines the current based on the signal. The received power level is measured for the base station and the candidate base station.

In step 9m, when the current cycle T _n × k corresponds to a constant multiple of the normal cycle T, the control unit 100 controls the control channel demodulation unit 106 before measuring the received power level described above. Then, the control signal transmitted from the current base station is received, and based on the demodulation result, the presence / absence of incoming call notification information indicating the occurrence of an incoming call addressed to the mobile station is confirmed. Here, when incoming call notification information is detected, incoming call notification processing (not shown) is executed to notify the user of the incoming call.

  In step 9n, the control unit 100 compares the received power level of the current base station measured by the quality measuring unit 105 in step 9m with the received power level of the candidate base station. If the received power level of the current base station is less than the received power level of the candidate base station, the process proceeds to step 9o. On the other hand, if the received power level of the current base station is greater than or equal to the received power level of the candidate base station Therefore, it is assumed that there is no need for handover, and the process proceeds to step 9B.

In step 9o, the control unit 100 determines whether or not a preset time has elapsed from the timer activation in step 9k by determining whether or not the timer activated in step 9k has timed out. Here, in a case where a preset time has elapsed, the process proceeds to step 9p, whereas, if not elapsed time set in advance, the process returns to step 9l, subsequently, received power for each measurement cycle T _n Measure and compare levels.

In step 9B, the control unit 100 decreases the value of the handover parameter L by “1” and ends the process. Thus, when the process proceeds to the next step 9A, it will select one step longer period than the current measurement period T _n.

  In step 9p, the control unit 100 first controls the transmission system 113 to make a handover request to the candidate base station detected in step 9c, and then controls each unit of the reception system and the transmission system 113 to perform predetermined processing. Hand over to the candidate base station according to the procedure of And the control part 100 controls the transmission system 113, performs position registration through a candidate base station, and transfers to step 9q.

In step 9q, the control unit 100 records the time at which the handover in step 9p is completed in the handover table stored in the storage unit 112, and proceeds to step 9C.
In step 9C, the control unit 100 increases the value of the handover parameter L by “1” and ends the process. Thus, when the process proceeds to the next step 9A, it will select one step shorter period than the current measurement period T _n.

  As described above, in the mobile station having the above-described configuration, in addition to the cell evaluation at the period T defined by the standard, two antennas are installed at a period according to the handover parameter L that changes according to the occurrence / non-occurrence of the handover. The current base station and the candidate base station are compared by performing switching and reception, and it is determined accurately and efficiently whether the candidate base station should perform handover.

That is, when handovers occur frequently (f is greater than or equal to the threshold th ₂ ), reception is performed by switching between two antennas at a cycle T _n (<T) according to the handover parameter L, and the candidate base station is always current. Handover is executed when the received power level is higher than that of the base station.

Thus, when a handover occurs frequently, in order to determine the need for handover performs reception by switching two antennas in a short cycle T _n than the normal period T definite by the standard, when switching antenna In addition, it is easy to detect a state in which the reception level of the candidate base station is lower than the reception power level of the current base station and is not suitable as a standby base station, and when that state is detected (No in step 9n), handover is performed. Without waiting for the current base station to continue waiting.

  Therefore, according to the mobile station having the above configuration, even if the user uses it in the fringe area, it is possible to accurately determine the necessity of the location registration process, thereby suppressing battery waste due to unnecessary location registration processing. it can.

When handovers occur frequently (f is greater than or equal to the threshold th ₂ ), as shown in FIG. 4B, the current base station, the candidate base station, and the candidate base station have a cycle T _n (<T) according to the handover parameter L. The occurrence of an incoming call is detected only at a timing corresponding to a constant multiple of the normal period T. For this reason, the reception time for monitoring the occurrence of an incoming call can be suppressed, and an increase in power consumption accompanying the increase in the frequency of determination can be suppressed.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. Further, for example, a configuration in which some components are deleted from all the components shown in the embodiment is also conceivable. Furthermore, you may combine suitably the component described in different embodiment.

As an example, in the third embodiment, when handover occurs frequently (f is greater than or equal to the threshold th ₂ ), the necessity for handover is confirmed by alternately switching the two antennas. Instead, for example, a vibrator (not shown) provided to notify an incoming call may be operated to confirm the necessity of handover while changing the distance from the base station. Also by this, since the necessity of a handover can be confirmed accurately by receiving paths in various directions, useless handover can be suppressed.
In addition, it goes without saying that the present invention can be similarly implemented even if various modifications are made without departing from the gist of the present invention.

The circuit block diagram which shows the structure of 1st and 2nd embodiment of the mobile radio | wireless terminal apparatus concerning this invention. The figure which shows the table which the memory | storage part of the mobile radio | wireless terminal apparatus of 1st Embodiment memorize | stores. The flowchart for demonstrating operation | movement of the mobile radio | wireless terminal apparatus of 1st Embodiment. The figure for demonstrating operation | movement of the mobile radio | wireless terminal apparatus of 1st and 2nd embodiment. The figure which shows the table which the memory | storage part of the mobile radio | wireless terminal apparatus of 2nd Embodiment memorize | stores. The flowchart for demonstrating operation | movement of the mobile radio | wireless terminal apparatus of 2nd Embodiment. The circuit block diagram which shows the structure of 3rd Embodiment of the mobile radio | wireless terminal apparatus concerning this invention. The figure which shows the table which the memory | storage part of the mobile radio | wireless terminal apparatus of 3rd Embodiment memorize | stores. The flowchart for demonstrating operation | movement of the mobile radio | wireless terminal apparatus of 3rd Embodiment. The figure for demonstrating operation | movement of the mobile radio | wireless terminal apparatus of 3rd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 ... Control part 101 ... Radio | wireless receiving part 102 ... GI removal part 103 ... FFT part 104 ... Signal separation part 105 ... Quality measurement part 106 ... Control channel demodulation part 107 ... Orthogonal code multiplication part 108 ... Depreciation unit 109 ... Demodulation unit 110 ... Channel deinterleaver 111 ... Channel decoder 112 ... Storage unit 113 ... Transmission system 114 ... Antenna switching unit

Claims (4)

In a mobile radio terminal device that performs radio communication by selecting a plurality of base stations accommodated in a mobile communication network,
Quality detection means for detecting reception quality;
A frequency detection means for detecting the frequency of occurrence of handover;
At a cycle corresponding to the frequency of said frequency detecting unit detects, comparing means for comparing the reception quality of the base station which finished the location registration, the reception quality of the other base station,
Depending on the comparison result of the comparison means, comprising a registration means for performing position registration,
The comparison means compares the reception quality of the base station whose location registration has been completed during a preset comparison time with the reception quality of another base station,
The registration means, based on the comparison result of the comparison means, when the reception quality of the base station that has completed the location registration during the comparison time is lower than the reception quality of other base stations, A mobile radio terminal device that performs location registration with a base station . In a mobile radio terminal device that performs radio communication by selecting a plurality of base stations accommodated in a mobile communication network,
Quality detection means for detecting reception quality;
A frequency detection means for detecting the frequency of occurrence of handover;
At a cycle corresponding to the frequency of said frequency detecting unit detects, comparing means for comparing the reception quality of the base station which finished the location registration, the reception quality of the other base station,
Depending on the comparison result of the comparison means, comprising a registration means for performing position registration,
The comparison means compares the reception quality of the base station whose location registration has been completed during a preset comparison time with the reception quality of another base station,
The registration means, based on the comparison result of the comparison means, when the reception quality of the base station that has completed the location registration exceeds the reception quality of other base stations during the comparison time, A mobile radio terminal device that does not register its location with the base station . In a mobile radio terminal device that performs radio communication by selecting a plurality of base stations accommodated in a mobile communication network,
Multiple antennas,
A selection means for selecting the antenna to be used;
Quality detection means for said selecting means using the selected antenna, detecting the reception quality,
A frequency detection means for detecting the frequency of occurrence of handover;
At a cycle corresponding to the frequency of said frequency detecting means detects a switching means for switching the antenna used by controlling the selection means,
At a cycle corresponding to the occurrence frequency of the frequency detecting unit detects, comparing means for comparing the reception quality of the base station which finished the location registration, the reception quality of the other base station,
Depending on the comparison result of the comparison means, comprising a registration means for performing position registration,
The comparison means compares the reception quality of the base station whose location registration has been completed during a preset comparison time with the reception quality of another base station,
The registration means, based on the comparison result of the comparison means, when the reception quality of the base station that has completed the location registration during the comparison time is lower than the reception quality of other base stations, A mobile radio terminal device that performs location registration with a base station . In a mobile radio terminal device that performs radio communication by selecting a plurality of base stations accommodated in a mobile communication network,
Multiple antennas,
A selection means for selecting the antenna to be used;
Quality detection means for said selecting means using the selected antenna, detecting the reception quality,
A frequency detection means for detecting the frequency of occurrence of handover;
At a cycle corresponding to the frequency of said frequency detecting means detects a switching means for switching the antenna used by controlling the selection means,
At a cycle corresponding to the occurrence frequency of the frequency detecting unit detects, comparing means for comparing the reception quality of the base station which finished the location registration, the reception quality of the other base station,
Depending on the comparison result of the comparison means, comprising a registration means for performing position registration,
The comparison means compares the reception quality of the base station whose location registration has been completed during a preset comparison time with the reception quality of another base station,
The registration means, based on the comparison result of the comparison means, when the reception quality of the base station that has completed the location registration exceeds the reception quality of other base stations during the comparison time, A mobile radio terminal device that does not register its location with the base station .

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