JP4488857B2 - Mobile radio terminal device - Google Patents

Description

  The present invention relates to a mobile wireless terminal device used in a wireless communication system such as a mobile phone system and a wireless LAN.

  As is well known, a mobile communication service adopting the CDMA2000 system provides a 1x service for performing voice communication and a 1xEV-DO service for performing packet data communication (see, for example, Patent Document 1).

  In packet data communication by 1xEV-DO, downlink high-speed packet communication up to 2.4 Mbps is possible, and the transmission rate is determined according to the reception state of the mobile station. For this reason, in order to improve the reception state in the mobile station, the mobile station employs reception diversity. This reception diversity is, for example, a configuration in which an outside antenna and a built-in antenna are combined, and both antennas are provided at a distance of about λ / 2.

  By the way, in the 1xEV-DO service, since many users use high-speed packets, sometimes a large number of mobile stations concentrate on one cell. In order to avoid this, it is important to divide a cell into a macro cell and a micro cell and distribute data as much as possible to provide data services.

  In the current 1xEV-DO service, the radius of the macro cell is 3 km and the radius of the micro cell is 100 m, and different frequencies are assigned to the macro cell and the micro cell.

For this reason, in the conventional system, for example, when packet data communication is performed by switching between a macro cell and a micro cell, it is necessary to switch frequencies, and thus there is a problem that high-speed handover cannot be performed.
JP 2004-066989 A

  In the conventional mobile radio terminal apparatus, for example, when packet data communication is performed by switching between a macro cell and a micro cell, it is necessary to switch frequencies, and thus there is a problem that high-speed handover cannot be performed.

  The present invention has been made to solve the above problem, and an object of the present invention is to provide a mobile radio terminal apparatus capable of detecting a base station suitable for handover at high speed even when handover is performed to a cell having a different frequency. And

  In order to achieve the above object, the present invention provides a first reception for receiving a radio signal from a base station using a first antenna in a mobile radio terminal apparatus that selectively performs radio communication with a plurality of base stations. Means, a second receiving means for receiving a radio signal from the base station using the second antenna, and causing the first receiving means and the second receiving means to receive a radio signal from the same base station to thereby receive diversity. A first control means for performing a reception speed detection means for detecting a reception speed of data by reception diversity; and a first reception means when the reception speed detected by the reception speed detection means falls below a preset threshold value. Control to continue receiving radio signals from the base station, and control the second receiving means to receive radio signals from neighboring base stations using a frequency different from the frequency used by the base station received by the first receiving means. It was set to configure and a second control means for detecting a base station suitable for receiving by receiving the.

  As described above, according to the present invention, when receiving diversity is performed to receive a radio signal from the same base station using two receiving means, and the receiving speed falls below a preset threshold value, one receiving means Thus, reception is continued, and the other receiving means receives a radio signal from another base station and detects a base station suitable for reception.

  Therefore, according to the present invention, since reception is continued by one receiving means, and the other receiving means receives a radio signal from another base station and detects a base station suitable for reception, the frequency used before and after the handover. Even if they are different, it is possible to provide a mobile radio terminal device capable of handover capable of detecting a base station suitable for handover at high speed.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, a CDMA (Code Division Multiple Access) type mobile phone apparatus corresponding to 1x service and 1xEV-DO service will be described as an example of a mobile radio terminal apparatus according to the present invention.

  The mobile radio terminal apparatus according to the present invention includes, for example, a main reception RF unit 4 and a sub reception RF unit 6 as shown in FIG. The reception RF unit 4 is connected to a go-out antenna 9 that is a main antenna, and the reception RF unit 6 is connected to a built-in antenna 10 that is a sub antenna.

  Although reception diversity is realized by such a configuration, it is desirable that the out-going antenna 9 and the built-in antenna 10 be provided apart from each other by λ / 2 because it is desirable to prevent correlation between the received signals. .

  And since this mobile radio | wireless terminal apparatus employ | adopts a CDMA system, the path separation for every antenna is possible. Therefore, instead of antenna switching, a plurality of finger receivers are provided to perform maximum ratio combining.

FIG. 2 shows a circuit block diagram of the mobile radio terminal apparatus.
This mobile radio terminal apparatus includes a control unit 1, a transmission RF unit 2, a transmission modem unit 3, a reception RF unit 4, an ADC 5, a reception RF unit 6, an ADC 7, a reception modem unit 8, and an antenna 9. , 10 and the throughput detection unit 11, the antenna 9, the reception RF unit 4 and the ADC 5 constitute a main reception system, and the antenna 10, the reception RF unit 6 and the ADC 7 constitute a sub reception system.

  The control unit 1 controls each unit of the mobile radio terminal device in an integrated manner. For example, when performing 1x service (voice communication), control is performed so that reception is performed by a transmission system including the transmission RF unit 2 and the transmission modem unit 3 and a main reception system including the reception modem unit 8 and one system. .

  When a 1xEV-DO service (packet data communication) is performed, a transmission system including the transmission RF unit 2 and the transmission modem unit 3, a main reception system including the reception modem unit 8, a sub reception system, and two systems To perform reception diversity.

  The control unit 1 controls the operation of each of the main reception system and the sub reception system, and performs intermittent reception. The control unit 1 controls the receiving modem unit 8 so as to selectively process the digital signals input from the two receiving systems.

  As a new control function, the control unit 1 has a function of performing handover by controlling the configuration related to the reception diversity according to the detection result of the throughput detection unit 11 during packet data communication.

  The transmission data is used by the transmission modem unit 3 to modulate a carrier wave. The signal thus obtained is spread by the transmission modem unit 3 with a predetermined spreading code, then up-converted by the transmission RF unit 2, and radiated from the antenna 9 to the space.

  Radio signals from base stations accommodated in the network of the mobile communication system are received by the antenna 9 and the antenna 10. A radio signal received by the antenna 9 is down-converted to a baseband signal by the reception RF unit 4, converted from an analog signal to a digital signal by the ADC 5, and input to the reception modem unit 8.

  A radio signal received by the antenna 10 is down-converted to a baseband signal by the reception RF unit 6, converted from an analog signal to a digital signal by the ADC 7, and input to the reception modem unit 8.

  The receiving modem unit 8 selectively processes the digital signals input from the two receiving systems under the control of the control unit 1. The receiving modem unit 8 includes searchers 81 and 82, fingers 83 to 86, and a synthesizer 87. In this example, the number of searchers is 2, and the number of fingers is 4.

  Searchers 81 and 82 select one of the digital signals obtained by the main reception system and the digital signal obtained by the sub reception system in accordance with an instruction from control unit 1.

  The searchers 81 and 82 generate a PN code based on an instruction from the control unit 1, despread the selected digital signal with the generated PN code, and a correlation level between the PN code and the digital signal. Is output to the control unit 1.

  That is, the control unit 1 varies the type and generation timing (phase) of the PN code generated by the searchers 81 and 82, causes the searchers 81 and 82 to despread the digital signal, and is suitable for reception from the result. Detecting the path.

  Then, the control unit 1 assigns a PN code so that the fingers 83 to 86 receive a path suitable for reception. The fingers 83 to 86 despread the digital signal of the reception system indicated by the control unit 1 among the two reception systems with the PN code assigned by the control unit 1.

  FIG. 3 shows a configuration example of the searcher 81. The searcher 81 includes an input switching unit 801, a PN code generator 802, a multiplier 803, an integrator 804, and a square circuit 805. Since the searcher 82 has the same configuration, the description thereof is omitted.

  The input switching unit 801 selectively outputs one of the output of the ADC 5 and the output of the ADC 7 to the first input terminal of the multiplier 803 in response to an instruction from the control unit 1. The PN code generator 802 generates a timing (phase) and type of PN code according to an instruction from the control unit 1, and outputs the generated PN code to the second input terminal of the multiplier 803.

  The multiplier 803 multiplies the digital signal input to the first input terminal by the PN code input to the second input terminal. The integrator 804 integrates the multiplication result of the multiplier 803 and outputs the result to the square circuit 805. Square circuit 805 squares the output of integrator 804. In this way, the correlation level between the digital signal and the PN code is obtained and output to the control unit 1.

The concept of the path search by the control unit 1 using the searchers 81 and 82 as described above will be described with reference to FIG. Here, the CDMA2000 system is taken as an example.
Each base station is arranged in the code space 2 ¹⁵ in multiples of 64 codes. Therefore, it is possible to assign a PN offset of 0 to 511. When the PN offset is “3”, as shown in FIG. 5, a search is performed from −64 to 0 to +64 in the case of a window length of 128 chips centering on the 64 × 3 = 192 code phase.

  Here, for example, it is assumed that a search result as shown in FIG. 6 is obtained. In this example, the control unit 1 causes the searcher 81 to perform a path search for the main reception system, and causes the searcher 82 to perform a path search for the sub reception system.

  In this case, the control unit 1 controls the reception RF unit 4 and the reception RF unit 6 to receive the same frequency in order to search for the same cell, and the searcher 81 and the searcher 82 have the same PN. A code is assigned.

  In the example illustrated in FIG. 6, the paths 71 to 74 are detected for the main reception system. However, since the paths 71 and 74 obtain the upper two powers, the control unit 1 sets the path 71 to the finger 83. At the same time, the path 74 is assigned to the finger 84.

  For the sub-reception system, the paths 75 to 78 are detected. Since the upper two powers are obtained from the paths 76 and 77, the control unit 1 assigns the path 76 to the finger 85 and the path 77. Is assigned to finger 86.

In FIG. 7, the structural example of the fingers 83-86 is shown. Each of the fingers 83 to 86 includes an input switching unit 810, a finger demodulating unit 820, and a synchronization tracking unit 830.
The input switching unit 810 selectively outputs one of the output of the ADC 5 and the output of the ADC 7 to the finger demodulation unit 820 and the synchronization tracking unit 830 in response to an instruction from the control unit 1.

  The finger demodulator 820 demodulates the input digital signal in accordance with an instruction from the controller 1. The synchronization follower 830 detects the phase shift and notifies the controller 1 of the phase shift. Thereby, the control unit 1 gives an instruction to the finger demodulation unit 820 in consideration of the phase shift detected by the synchronization tracking unit 830.

  The finger demodulator 820 includes a PN code generator 821, a multiplier 822, and an integrator 823. The PN code generator 821 generates a timing (phase) and type of PN code according to an instruction from the control unit 1, and outputs the generated PN code to the second input terminal of the multiplier 822.

  The multiplier 822 inputs the digital signal selected by the input switching unit 810 to the first input terminal, and multiplies the digital signal by the PN code input to the second input terminal. The integrator 823 integrates the multiplication result of the multiplier 822 and outputs the demodulation result obtained thereby to the synthesizer 87.

  The synchronization tracking unit 830 includes PN code generators 831a and 831b, multipliers 832a and 832b, integrators 833a and 833b, square circuits 834a and 834b, and an adder circuit 835.

  The PN code generator 831a generates the same PN code as the PN code generated by the PN code generator 821 by advancing the phase by 1/2 chip from the PN code generator 821. Output to the second input terminal of the multiplier 832a.

  The multiplier 832a receives the digital signal selected by the input switching unit 810 at the first input terminal, and multiplies the digital signal by the PN code input at the second input terminal. The integrator 833a integrates the multiplication result of the multiplier 832a and outputs the result to the square circuit 834a. The square circuit 834a squares the output of the integrator 833a.

  The PN code generator 831b generates the same PN code as the PN code generated by the PN code generator 821 with a phase delayed by 1/2 chip from the PN code generator 821, and multiplies the generated PN code. To the second input terminal of the device 832b.

  The multiplier 832b inputs the digital signal selected by the input switching unit 810 to the first input terminal, and multiplies the digital signal by the PN code input to the second input terminal. The integrator 833b integrates the multiplication result of the multiplier 832b and outputs the result to the square circuit 834b. The square circuit 834b squares the output of the integrator 833b.

  The square results of the square circuit 834 a and the square circuit 834 b are added by the addition circuit 835 and output to the control unit 1. The control unit 1 detects a phase shift based on the output of the adder circuit 835, and causes the PN code generator 821 to generate a PN code at a timing when the phase shift is corrected.

  As described above, the result of despreading obtained by the fingers 83 to 86 is output to the combiner 87. The combiner 87 combines the results of despreading of the fingers 83 to 86 with a maximum ratio, and outputs the result as demodulated data to a subsequent signal processing unit (not shown). According to such reception diversity, reception quality is improved and high-speed downlink packet data communication is possible.

  The throughput detector 11 detects the throughput from the base station to the mobile radio terminal apparatus based on the demodulated data obtained by the combiner 87. As this detection method, for example, as shown in FIG. 8, a method of monitoring the amount of packet data received while the timer is started and the time t elapses, or a method of calculating an average interval in packet reception can be considered. The detection result is notified to the control unit 1.

  Next, the operation of the mobile radio terminal apparatus will be described. Here, a case where the mobile radio terminal apparatus is placed in an environment as shown in FIG. 9 will be described as an example. In the environment shown in FIG. 9, cells C and D each indicate a macro cell, and the base stations forming these cells both provide 1xEV-DO service at frequency f1 and perform high-speed packet data communication. The radius of the macro cell is assumed to be approximately 3 km.

  A microcell group is formed in a region where the cell C and the cell D overlap. Each base station forming a micro cell provides a 1xEV-DO service at a frequency f2. The radius of the microcell is assumed to be approximately 100 m.

  Among the microcells constituting the microcell group, the cell A is located in a region where the cell C and the cell D overlap in the vicinity of the center of the microcell group. On the other hand, the cell B is located at the outer edge of the microcell group in the macrocell C.

  Cell A provides neighboring cell information as shown in FIG. 10 to the mobile radio terminal apparatus. In this adjacent cell information, since the cell A is located at a point surrounded by other microcells, the PN code identification number used by the adjacent microcell and the frequency f2 used by the microcell are notified.

  Cell B provides neighboring cell information as shown in FIG. 11 to the mobile radio terminal apparatus. In this adjacent cell information, since the cell B is located at the outer edge of the microcell group, the identification number of the PN code used by the adjacent microcell, the frequency f2 used by the microcell, and the PN code used by the macrocell such as the cell D And the frequency f1 used in the macro cell are notified.

  Further, the cell C provides neighboring cell information as shown in FIG. 12 to the mobile radio terminal apparatus. In this neighboring cell information, since a micro cell exists in the cell C, the identification number of the PN code used by the adjacent macro cell D, the frequency f1 used by the macro cell, and the identification number of the PN code used by the micro cell, The frequency f2 used in the microcell is notified.

  That is, when the cell is a macro cell or a micro cell and is located at the outer edge of the micro cell group, information on both the micro cell and the macro cell is provided to the mobile radio terminal apparatus. On the other hand, when the cell is a micro cell and is surrounded by other micro cells, only the information about the micro cell is provided even within the macro cell.

  When a mobile wireless terminal device located near the cell A performs high-speed packet data communication using the 1xEV-DO service, even if the user moves, the mobile wireless terminal device is located in another microcell. It is preferable to receive service from the microcell.

  On the other hand, when the mobile wireless terminal device located at the outer edge of the microcell group such as the cell B is performing high-speed packet data communication using the 1xEV-DO service, it is necessary to receive the service from the macrocell when the mobile radio terminal device is disconnected from the microcell. There is.

  When service is received from a macro cell in this way, the amount of packet data received addressed to itself is reduced as compared to the case of using a micro cell, and the throughput may deteriorate. For this reason, the mobile radio terminal apparatus performs handover between the micro cell and the macro cell by a process as described below.

  FIG. 13 shows a control operation related to the handover, which is performed by the control unit 1. This control program is stored in the control unit 1 and is repeatedly executed until the power is turned off when the mobile radio terminal device is turned on.

  First, in step 13a, the control unit 1 determines whether or not the throughput has fallen below a preset threshold based on the detection result of the throughput detection unit 11. If the throughput falls below a preset threshold value, the process proceeds to step 13b.

  On the other hand, if the throughput is not lower than a preset threshold value, the throughput monitoring is continued. Note that if the mobile radio terminal apparatus does not request the base station to transmit packet data and the throughput decreases, the process does not proceed to step 13b.

Here, it is assumed that the 1xEV-DO service has been received from the cell B so far, and the throughput with the cell B is lowered.
In step 13b, the control unit 1 uses the neighboring cell information received from the pending cell B and the like, and the neighboring cell using a frequency (for example, f1) different from the frequency f2 used for communication with the pending cell B. It is determined whether or not exists.

  If there is an adjacent cell using a different frequency, the process proceeds to step 13c. On the other hand, if there is no adjacent cell using a different frequency, the process proceeds to step 13a to monitor the throughput. Here, it is assumed that cell C exists as an adjacent cell.

  In step 13c, the control unit 1 controls the main reception system, the sub reception system, and the searchers 81 and 82, detects Ec / No for the same cell (for example, cell B) having the same frequency, and proceeds to step 13d.

  In step 13d, the control unit 1 obtains the difference d between the main reception system and the sub reception system based on the result detected in step 13c, and proceeds to step 13e. The index for examining the difference in reception is not limited to Ec / No, but RSCP (Received Signal Code Power) or the like can be considered.

  In step 13e, the control unit 1 temporarily suspends reception diversity, and receives a pending cell B using only the main reception system. For this reason, as shown in FIG. 14, the reception signals of the main reception system are input to all the fingers 83 to 86, and the main reception system path previously searched by the searcher 81 is assigned to the fingers 83 to 86. The program proceeds to step 13f.

  In step 13f, the control unit 1 uses the sub reception system for path search for the cell C having a frequency different from that of the main reception system. Therefore, the reception RF unit 2 is caused to receive the frequency f1, and as shown in FIG. 14, the reception signal of the sub reception system is input to the searcher 82 to perform path search, and the process proceeds to step 13g. Note that the searcher 81 receives a reception signal of the main reception system and performs a path search for the cell B.

  In step 13g, the control unit 1 corrects the total correlation level value (see FIG. 15) of each path obtained from the search result of the cell C performed in step 13f with the reception performance difference d obtained in step 13d, and The total value (see FIG. 16) of the correlation level of each path of the cell B of the main reception system detected by the searcher 81 is compared to determine whether or not to hand over to the cell C.

  Here, when the total correlation level of each path of the sub reception system (cell C) considering the reception performance difference d is greater than the total correlation level of each path of the main reception system (cell B) The control unit 1 performs handover so as to receive a signal from the cell C, and performs control so that reception diversity is performed again between the main reception system and the sub reception system.

  As described above, in the mobile radio terminal apparatus having the above-described configuration, when the throughput from a pending cell falls below a preset threshold, reception diversity is temporarily suspended and packet data reception is performed by the main reception system. At the same time, the reception quality of signals from adjacent cells having different frequencies is verified in the sub reception system, and depending on the quality of the received signals from the adjacent cells, handover is performed to the adjacent cells.

  Therefore, according to the mobile radio terminal apparatus having the above configuration, adjacent cells having different frequencies can be verified as handover destinations using the sub-reception system, so that even when the used frequencies are different before and after handover, fast handover is possible. Is possible.

  Further, in the mobile radio terminal apparatus having the above configuration, the necessity for handover is determined by correcting the reception performance difference between the main reception system and the sub reception system, so that the above determination can be made accurately.

  Furthermore, only the cells (for example, cell B) located at the outer edge of the microcell group provide information about cells having different frequencies to the mobile radio terminal apparatus. For this reason, the mobile radio terminal apparatus performs a path search for a cell having a different frequency only when it is located in a cell located at the outer edge of the microcell group, and when it is located in a cell in the microcell group like the cell A. Will perform cell search only for microcells. For this reason, the mobile radio terminal apparatus does not perform a path search for different frequencies unnecessarily.

  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, for example, in the above embodiment, when the throughput from the pending cell is reduced, the reception performance difference between the main reception system and the sub reception system is obtained, but regardless of the decrease in throughput, The reception performance difference may be obtained in advance. For example, the reception performance difference may be obtained at the start of packet data communication.

Further, in order to increase the measurement accuracy of the reception performance difference, the reception performance difference may be obtained a plurality of times, and an average of these may be used in step 13g. Alternatively, the reception performance difference may be obtained periodically, the reception performance difference obtained last may be stored, and this value may be used in step 13g.
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 figure which shows that the mobile radio | wireless terminal apparatus concerning this invention is equipped with a main receiver and a sub receiver. The circuit block diagram which shows the structure of the mobile radio | wireless terminal apparatus concerning this invention. The circuit block diagram which shows the structure of the searcher of the mobile radio | wireless terminal apparatus shown in FIG. The figure for demonstrating the concept of the path search of the mobile radio | wireless terminal apparatus shown in FIG. The figure for demonstrating the search window of the mobile radio | wireless terminal apparatus shown in FIG. The figure for demonstrating the search result of the mobile radio | wireless terminal apparatus shown in FIG. The circuit block diagram which shows the structure of the finger of the mobile radio | wireless terminal apparatus shown in FIG. The figure for demonstrating the throughput measurement of the mobile radio | wireless terminal apparatus shown in FIG. The figure which shows an example of the environment where the mobile radio | wireless terminal apparatus concerning this invention is utilized. The figure which shows an example of the periphery cell information which the cell A shown in FIG. 9 provides to a mobile radio | wireless terminal apparatus. The figure which shows an example of the periphery cell information which the cell B shown in FIG. 9 provides to a mobile radio | wireless terminal apparatus. The figure which shows an example of the periphery cell information which the cell C shown in FIG. 9 provides to a mobile radio | wireless terminal apparatus. The flowchart for demonstrating operation | movement of the mobile radio | wireless terminal apparatus shown in FIG. The figure which shows the signal allocated to the finger and searcher of the mobile radio | wireless terminal apparatus shown in FIG. The figure which shows the search result of the searcher of the mobile radio | wireless terminal apparatus shown in FIG. The figure which shows the search result of the searcher of the mobile radio | wireless terminal apparatus shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Control part, 2 ... Transmission RF part, 3 ... Transmission modem part, 4 ... Reception RF part, 5 ... ADC, 6 ... Reception RF part, 7 ... ADC, 8 ... Reception modem part, 9 ... Outing antenna, 10 ... built-in antenna, 11 ... throughput detector, 81, 82 ... searcher, 83, 84, 85, 86 ... finger, 87 ... synthesizer, 801 ... input switching part, 802 ... PN code generator, 803 ... multiplier, 804 Integrator 805 Square circuit 810 Input switching unit 820 Finger demodulator 821 PN code generator 822 Multiplier 823 Integrator 830 Synchronization follower 831a, 831b PN code Generator, 832a, 832b ... multiplier, 833a, 833b ... integrator, 834a, 834b ... square circuit, 835 ... adder circuit (Σ).

Claims (9)

In a mobile radio terminal apparatus that selectively performs radio communication with a plurality of base stations,
First receiving means for receiving a radio signal from the base station using a first antenna;
Second receiving means for receiving a radio signal from the base station using a second antenna;
First control means for performing reception diversity by causing the first receiving means and the second receiving means to receive a radio signal from the same base station;
A reception speed detecting means for detecting a reception speed of data by the reception diversity;
When the reception speed detected by the reception speed detection means is less than or equal to a preset threshold value, the first reception means is controlled to continue reception of radio signals from the base station, and the second reception means And second control means for detecting a base station suitable for reception by receiving a radio signal from a neighboring base station using a frequency different from the frequency used by the base station received by the first receiving means. A mobile radio terminal apparatus. In a mobile radio terminal apparatus that selectively performs radio communication with a plurality of base stations,
First receiving means for receiving a radio signal from the base station using a first antenna;
Second receiving means for receiving a radio signal from the base station using a second antenna;
First demodulation means for demodulating the received signal;
Second demodulation means for demodulating the received signal;
Combining means for combining the demodulation result of the first demodulation means and the demodulation result of the second demodulation means;
Throughput detection means for detecting throughput based on the demodulation result synthesized by the synthesis means;
First detection means for detecting a path suitable for reception based on a reception signal received by the first reception means;
Second detection means for detecting a path suitable for reception based on a reception signal received by the second reception means;
The first receiving means and the second receiving means are controlled to receive a radio signal from the same base station, and based on the detection result of the first detecting means and the detection result of the second detecting means, First control means for selectively inputting the received signals respectively obtained by the first receiving means and the second receiving means to the first demodulating means and the second demodulating means;
When the throughput detected by the throughput detection unit is equal to or less than a preset threshold, the second reception of a radio signal from a neighboring base station using a frequency different from the frequency used by the base station received by the first reception unit A mobile radio terminal apparatus comprising: a second control unit configured to cause the second detection unit to detect a path suitable for reception from the neighboring base station by controlling the unit to receive. The first detection means detects a plurality of paths suitable for reception together with a degree suitable for reception based on the received signal received by the first reception means,
The second detection means detects a plurality of paths suitable for reception together with a degree suitable for reception based on the received signal received by the second reception means,
And a base station detection means for detecting a base station suitable for reception based on the detection result of the first detection means and the detection result of the second detection means,
The first control means controls the radio signal from the base station detected by the base station detection means to be received by the first receiving means and the second receiving means. The mobile radio terminal device described in 1.   The base station detection means receives a signal based on a difference in reception performance between the first reception means and the second reception means, a detection result of the first detection means, and a detection result of the second detection means. The mobile radio terminal apparatus according to claim 3, wherein a base station suitable for the mobile station is detected. Further, when the first receiving means and the second receiving means receive a radio signal from the same base station, based on the detection result of the first detection means and the detection result of the second detection means, A third control means for obtaining a difference in reception performance between the first receiving means and the second receiving means;
The mobile radio terminal apparatus according to claim 4, wherein the base station detection means uses a difference in reception performance obtained by the third control means. Further, the first receiving means and the second receiving means are controlled to receive a radio signal from the same base station, and based on the detection result of the first detecting means and the detection result of the second detecting means. And third control means for obtaining a difference in reception performance between the first receiving means and the second receiving means,
The mobile radio terminal apparatus according to claim 4, wherein the base station detection means uses a difference in reception performance obtained by the third control means. When the throughput detected by the throughput detection means is less than or equal to a preset threshold value,
The third control means controls the first receiving means and the second receiving means to receive a radio signal from the same base station, and the detection result of the first detecting means and the detection of the second detecting means Based on the result, a difference in reception performance between the first receiving means and the second receiving means is obtained ,
Thereafter, the second control means controls the second receiving means to receive a radio signal from a peripheral base station using a frequency different from the frequency used by the base station received by the first receiving means, mobile radio terminal apparatus according to claim 5, characterized in Rukoto to find the path which is suitable for receiving from the neighboring base station to said second detection means. The third control means obtains a plurality of samples of the difference in reception performance, averages them,
8. The mobile radio terminal apparatus according to claim 5, wherein the base station detection means uses a difference in reception performance obtained by averaging by the third control means. Furthermore, comprising an acquisition means for acquiring information about a frequency used by a neighboring base station from the base station,
When the information acquired by the acquisition unit includes information about the neighboring base station , and the throughput detected by the throughput detection unit falls below a preset threshold, the second control unit 3. The control unit according to claim 2, wherein the second receiving unit is controlled to receive a radio signal from a base station, thereby causing the second detecting unit to detect a path suitable for reception from the neighboring base station. The mobile radio terminal device described in 1.

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