JP4567919B2 - Mobile radio terminal - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mobile radio terminal used in a mobile radio communication system such as a car phone system or a mobile phone system adopting a CDMA (Code Division Multiple Access) system.
[0002]
[Prior art]
As is well known, in a mobile radio communication system such as a car phone system or a mobile phone system adopting the CDMA system, a communication area is called a cell, and a radius is divided into several hundred m to several km units. ing. Then, the base station notifies the mobile station of information related to a cell adjacent to the cell to which the base station belongs (hereinafter referred to as an adjacent cell).
[0003]
This information includes the identification information of the spread signal necessary for the mobile station to receive the radio signal from each adjacent cell, and the information indicating the priority to be connected to the mobile station for each adjacent cell. Yes.
[0004]
On the other hand, the mobile station performs a path search for the currently located cell (hereinafter referred to as a stay cell) and adjacent cells based on the information broadcast from the base station, and performs communication for each cell. Sixteen suitable paths are detected and recorded in the storage unit, and among the recorded paths, the path of the cell having a higher priority is preferentially used for communication.
[0005]
However, a cell having a low priority has not only a small number of effective paths but also a low possibility of being used for communication, and records information of the same number of paths as the staying cell in the storage unit. There is a problem that the storage capacity of the storage unit is consumed due to the low path information.
[0006]
In addition, the mobile station periodically updates the path information of each cell. However, as described above, since the update process is also performed for a path with low utility value, an unnecessary load is imposed on the control unit. Has been put on and contributed to the waste of electricity.
[0007]
[Problems to be solved by the invention]
The conventional mobile radio terminal has a problem that the storage capacity and power consumption of the storage unit are wasted because the information is held and updated even for paths with low utility value.
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a mobile radio terminal capable of preventing the storage capacity and power consumption of the storage unit from being wasted.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the present invention according to claim 1 wirelessly communicates with a base station by a CDMA system, and receives rake reception from a plurality of base stations respectively forming different radio zones through a plurality of communication paths. In a mobile radio terminal that can be performed, a priority information acquisition unit that acquires information indicating priorities respectively assigned to a plurality of radio zones from a base station, and the priority information acquisition unit Candidate path number determining means for determining the number of candidate paths for each wireless zone according to the priority of each wireless zone, and receiving the radio signal from each wireless zone, and said candidate path number determining means for each wireless zone Path detection means for detecting paths suitable for reception by the number of candidate paths determined by the storage means, storage means for storing path information detected by the path detection means, and storage means for storing Based on the path information that was to be configured by including a receiving means for performing rake reception.
[0009]
In the mobile radio terminal having the above-described configuration, when obtaining a candidate for a path to be received, the number of candidate paths is obtained by the number of candidate paths determined for each radio zone in accordance with the priorities assigned in advance to the plurality of radio zones. To keep.
[0010]
Therefore, according to the mobile radio terminal having the above-described configuration, path candidates for each radio zone are held in the number corresponding to the priority, so that it is possible to prevent detecting and holding an unnecessarily large number of path candidates. The storage capacity of the storage means can be saved, unnecessary processing can be omitted, and power consumption can be reduced.
[0011]
In order to achieve the above object, the present invention according to claim 3 wirelessly communicates with a base station by a CDMA system, and a plurality of base stations respectively forming different wireless zones are raked through a plurality of communication paths. In a mobile radio terminal capable of receiving, reception level detection means for receiving radio signals from a plurality of radio zones and detecting the respective reception levels, and each radio obtained by the reception level detection means Candidate path number determining means for determining the number of candidate paths for each wireless zone according to the reception level of the zone, and receiving the radio signal from each wireless zone, and the candidate path number determining means for each wireless zone The path detection means for detecting paths suitable for reception by the number of candidate paths, a storage means for storing information on the paths detected by the path detection means, and the storage means Based on the information of the path to be, and to be configured by including a receiving means for performing rake reception.
[0012]
In the mobile radio terminal having the above-described configuration, when obtaining a candidate for a path to be received, the number of candidate paths determined for each radio zone according to the reception power level of each radio zone is obtained and held. Yes.
[0013]
Therefore, according to the mobile radio terminal having the above-described configuration, path candidates for each radio zone are held in the number corresponding to the reception power level of each radio zone, so that an unnecessarily large number of path candidates are detected and held. Can be prevented, the storage capacity of the storage means can be saved, unnecessary processing can be omitted, and power consumption can be reduced.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, this embodiment will be described with reference to the drawings.
FIG. 1 shows the configuration of a CDMA mobile radio terminal apparatus according to an embodiment of the present invention. In particular, the following description will focus on the receiving system according to the present invention.
[0015]
The transmission device 12 modulates transmission data such as digitized voice and data by a digital modulation scheme such as PSK (Phase Shift Keying) modulation, spreads the modulated data using a spreading code, and wideband To baseband signal.
[0016]
In the transmission device 12, the spread baseband signal is up-converted into a radio frequency signal and input to the antenna 10 through the duplexer 11. The input radio frequency signal is radiated to the space from the antenna 10 and transmitted toward the base station BS accommodated in the mobile communication network.
[0017]
On the other hand, the radio signal transmitted from the base station BS is received by the antenna 10 and input to the receiving device 13 through the duplexer 11. The receiving device 13 includes a radio circuit 14, an intermediate frequency circuit 15, and a RAKE receiver 16.
[0018]
In the radio circuit 14, the radio signal received from the duplexer 11 is input to the attenuator 14a, where it is attenuated by a preset amount. The signal that has passed through the attenuator 14a is amplified to a predetermined level by the amplifier 14b, mixed with the local oscillation signal generated by the frequency synthesizer 14b by the mixer 14c, and down-converted to an intermediate frequency.
[0019]
The signal down-converted to the intermediate frequency is input to the intermediate frequency circuit 15 and amplified to a predetermined level by the amplifier 15a. The amplification result is input to a band pass filter (BPF) 15b, and only a desired band is passed from here to the mixer 15c.
[0020]
In the mixer 15c, the signal that has passed through the bandpass filter 15b is mixed with the signal generated by the frequency synthesizer 15d and converted into a baseband signal. This baseband signal is converted into a digital signal by an A / D converter (A / D) 15 e and input to the RAKE receiver 16.
[0021]
The RAKE receiver 16 includes a searcher 16a, fingers 16b, 16c, and 16d, and a symbol synthesizer 16e. The digital signal is input to the searcher 16a and the fingers 16b, 16c, and 16d, respectively.
[0022]
The searcher 16a performs a despreading process using various spreading codes on the digital signal based on an instruction from the control unit 100, and a signal arriving through a plurality of paths from the base station to the terminal. The so-called multipath detection process is performed, and the received power level and reception timing (despreading timing) of the detected path are obtained and notified to the control unit 100.
[0023]
The fingers 16b, 16c, and 16d perform despreading processing on the digital signal by using the same spreading code as that used for spreading on the transmission side at the despreading timing assigned by the control unit 100.
[0024]
The symbol synthesizer 16e synthesizes the multipath components despread by the fingers 16b, 16c and 16d in consideration of the despreading timing assigned to each finger 16b, 16c and 16d.
[0025]
The signal synthesized by the symbol synthesizer 16e is subjected to demodulation processing corresponding to digital modulation on the transmission side by the signal processing unit 17 at the subsequent stage, and the received data is reproduced.
[0026]
The control unit 100 includes a CPU, a ROM, a RAM, and the like, and the CPU controls each unit of the mobile radio terminal device according to a control program and control data stored in the ROM. Thus, for example, control related to management of paths that may be received by the fingers 16b, 16c, and 16d (hereinafter referred to as candidate paths) is performed.
[0027]
In the control related to the management of candidate paths, the control unit 100 periodically detects a plurality of candidate paths and records them in a path table storage area 200a, which will be described later, in preparation for handover. , 16c, and 16d are updated. As a new control function, a function for controlling the number of candidate paths is provided.
[0028]
In this new function, the control unit 100 extracts cell information from the received data reproduced by the signal processing unit 17. This cell information is transmitted from the staying cell, and includes identification information of the spreading code used for receiving signals from the staying cell and its neighboring cells, and information indicating the priority assigned to these cells. included.
[0029]
And the control part 100 controls the searcher 16a, and determines the holding | maintenance number of candidate paths for each cell according to the respectively assigned priority and the received power from the object cell.
[0030]
The storage unit 200 is a storage medium such as a ROM and a RAM, and has an area for storing various information including telephone book data that can be arbitrarily stored by the user, and also includes the path table storage area 200a. .
[0031]
In the path table storage area 200a, information is read and written by the control unit 100, and information for each cell is stored as shown in FIG. This information includes the type of spreading code used for communication, Status information indicating whether or not the mobile radio terminal apparatus is a cell used for communication, Carrier RSSI, and path information regarding the path to the cell.
[0032]
This path information includes the number of candidate paths determined by the control unit 100 according to the priority order of the cells notified from the base station of the staying cell, and the average state information of each of the plurality of candidate paths detected by the searcher 16a. Consists of.
[0033]
Also, the averaged state information is based on the average result of the reception quality (for example, RSCP, RxAGC, etc.) of the corresponding path and the reception path flag indicating whether or not reception is performed by any of the fingers 16b, 16c, and 16d. Become.
[0034]
In addition, although illustration is abbreviate | omitted in FIG. 1, the power supply part which supplies the electric power for operating each part mentioned above as a component of this apparatus, and has a battery which can be charged / discharged repeatedly exists.
[0035]
Next, the operation of the mobile radio terminal apparatus having the above configuration will be described. In the following description, processing for controlling the number of candidate paths that may be received by the fingers 16b, 16c, and 16d will be described. Further, in the following description, the case where the cell arrangement is in the state shown in FIG. 3 will be described as an example.
[0036]
As shown in this figure, the mobile radio terminal apparatus uses cell A as a staying cell, and neighboring cells B, C, D, and cells E, F, G, H, as neighboring cells of the base station of cell A, I and J exist, the priority of staying cell A is the highest, and the higher priority is set to other cells as it is closer to staying cell A.
[0037]
In FIG. 3, the higher the priority, the higher the priority, the maximum value being “7”, and the minimum value being “1”. Although not shown in this figure, the priority “0” indicates a cell that is not monitored.
[0038]
In addition, the cell A base station transmits the above cell information to the mobile radio terminal device staying in the cell, and when the control unit 100 obtains this information, the information is organized for each cell. Recorded in the path table storage area 200a.
[0039]
FIG. 4 is a flowchart for explaining a process for controlling the number of candidate paths held. This control is performed by the control unit 100 and is repeatedly executed until the power is turned off when the power is turned on.
[0040]
First, in step 4a, each of the staying cell A and neighboring cells B, C, D, E, F, G, H, I, and J is determined based on the priority included in the cell information notified from the staying cell A. A process for determining the number of candidate paths to be detected is performed.
[0041]
FIG. 5 is a flowchart for explaining this process, and this process is performed for each cell. Here, this processing will be described with reference to FIG.
In step 5a, the priority of the cell to be processed is detected from the path table storage area 200a, and the process proceeds to step 5b.
[0042]
In step 5b, it is determined whether or not the priority detected in step 5a is equal to or less than the median “4”. Here, when the priority is “4” or less, the process proceeds to step 5c, and when the priority is “5” or more, the process proceeds to step 5d.
[0043]
In step 5c, “4” is recorded in the “number of candidate paths” in the area of the path table storage area 200a corresponding to the cell to be processed, and the process ends.
In step 5d, “16” is recorded in the “number of candidate paths” in the area of the path table storage area 200a corresponding to the cell to be processed, and the process ends.
As described above, when the process shown in FIG. 5 is completed for each cell, the process proceeds to step 4b.
[0044]
Again, a description will be given with reference to FIG.
In step 4b, for the cell in which “16” is recorded as the number of candidate paths in the process of step 4a, the process of reviewing the “number of candidate paths” is performed based on the total received power of this cell.
[0045]
FIG. 6 is a flowchart for explaining this process. This process is performed for all cells in which “16” is set as the number of candidate paths in the process of step 4a. Here, this process will be described with reference to FIG.
[0046]
In step 6a, the searcher 16a is controlled to detect the level of the total received power of the cell to be processed, and the process proceeds to step 6b. This level is the level of the signal obtained when the received signal is despread using the spreading code assigned to the cell, and the spreading code to be used is based on the cell information notified from the staying cell A. Can be identified.
[0047]
In step 6b, it is determined whether or not the received power level detected in step 6a is equal to or higher than a threshold th_16.
Here, when the received power level is equal to or higher than the threshold th_16, the process is terminated without updating the “number of candidate paths” in the area of the path table storage area 200a corresponding to the cell to be processed. When the level is less than the threshold th_16, the process proceeds to Step 6c.
[0048]
In step 6c, it is determined whether or not the received power level detected in step 6a is equal to or higher than a threshold th_10 (<th_16).
If the received power level is greater than or equal to the threshold th_10, the process proceeds to step 6d. On the other hand, if the received power level is less than the threshold th_10, the process proceeds to step 6e.
[0049]
In step 6d, the “number of candidate paths” in the area of the path table storage area 200a corresponding to the cell to be processed is updated to “10”, and the process ends.
[0050]
In step 6e, it is determined whether or not the received power level detected in step 6a is equal to or higher than a threshold th_8 (<th_10).
If the received power level is greater than or equal to the threshold th_8, the process proceeds to step 6f. On the other hand, if the received power level is less than the threshold th_8, the process proceeds to step 6g.
[0051]
In step 6f, the “number of candidate paths” in the area of the path table storage area 200a corresponding to the cell to be processed is updated to “8”, and the process ends.
[0052]
In step 6g, it is determined whether or not the received power level detected in step 6a is equal to or higher than a threshold th_6 (<th_8).
If the received power level is greater than or equal to the threshold th_6, the process proceeds to step 6h. On the other hand, if the received power level is less than the threshold th_6, the area of the path table storage area 200a corresponding to the cell to be processed is stored. The process ends without updating the “candidate path number”.
[0053]
In step 6h, the “number of candidate paths” in the area of the path table storage area 200a corresponding to the cell to be processed is updated to “6”, and the process ends.
[0054]
As described above, when the process shown in FIG. 6 is completed for all cells in which “16” is set as the number of candidate paths in the process of step 4a, the process ends.
[0055]
In parallel with the processing shown in FIGS. 5 and 6, the control unit 100 periodically performs a process of reviewing candidate paths for each cell in preparation for handover.
[0056]
In this process, the control unit 100 detects candidate paths for each cell by the number of candidate paths determined in the processes shown in FIGS. 5 and 6, and stores the detected candidate path information in the path table storage area 200a. Record and update the paths assigned to fingers 16b, 16c, 16d as needed.
[0057]
As described above, in the mobile radio terminal having the above configuration, based on the priority information of neighboring cells notified from the base station of the staying cell A, the higher the priority, the more candidate paths are held. I am doing so.
[0058]
Therefore, according to the mobile radio terminal having the above-described configuration, the higher the priority cell, the more candidate paths are held. The storage capacity of the storage unit 200 required for holding can be used efficiently.
In addition, since there is no need to review unnecessary candidate paths that are held unnecessarily, the load on the control unit 100 can be reduced and the power consumption can be reduced.
[0059]
Furthermore, in the mobile radio terminal having the above-described configuration, the number of candidate paths held based on the priority is variable according to the received power level for each cell. For cells with a low received power level, the number of candidate paths held is limited, so that the storage unit 200 can be used more efficiently and the load on the control unit 100 is also appropriate.
[0060]
The present invention is not limited to the above embodiment.
For example, in the above embodiment, the number of candidate path holdings is set to be small for a cell with a low reception power level even if the priority is high. Instead, for example, reception is possible even if the priority is low. For cells with a high power level, a large number of candidate paths may be set.
[0061]
The number of candidate paths held according to the received power level is also revised after setting the number of candidate paths held based on priority. However, the number of candidate paths is not limited to this. The number may be set, or prior to setting the number of candidate paths held based on priority.
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.
[0062]
【The invention's effect】
As described above, according to the present invention, when obtaining a candidate for a path to be received, the number of candidate paths is the same as the number of candidate paths determined for each wireless zone in accordance with the priorities assigned in advance to a plurality of wireless zones. Seeking to hold.
[0063]
Therefore, according to the present invention, the number of path candidates in each radio zone is held in the number corresponding to the priority of each radio zone, so that it is possible to prevent unnecessarily detecting and holding a large number of path candidates. Thus, it is possible to provide a mobile radio terminal capable of saving the storage capacity of the storage means, omitting unnecessary processing, and reducing power consumption.
[0064]
In addition, in the present invention, when obtaining a candidate for a path to be received, the above-mentioned path candidates are obtained and held by the number of candidate paths determined for each radio zone according to the received power level of each radio zone.
[0065]
Therefore, according to the present invention, the number of path candidates for each radio zone is maintained in the number corresponding to the reception power level of each radio zone, so that it is possible to prevent detecting and maintaining an unnecessarily large number of path candidates. In addition, it is possible to provide a mobile radio terminal capable of saving the storage capacity of the storage means, omitting unnecessary processing, and reducing power consumption.
[Brief description of the drawings]
FIG. 1 is a circuit block diagram showing a configuration of an embodiment of a mobile radio terminal according to the present invention.
FIG. 2 is a view for explaining information stored in a path table storage area of the mobile radio terminal shown in FIG. 1;
3 is a diagram showing an example of cell arrangement in a mobile radio communication system in which the mobile radio terminal shown in FIG. 1 is used.
4 is a flowchart for explaining processing for controlling the number of candidate path holdings of the mobile radio terminal shown in FIG. 1;
FIG. 5 is a flowchart for explaining in detail the processing shown in FIG. 4;
6 is a flowchart for explaining in detail the processing shown in FIG. 4;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Antenna 11 ... Duplexer 12 ... Transmitter 13 ... Receiver 14 ... Radio circuit 14a ... Attenuator 14b ... Amplifier 14c ... Mixer 14d ... Frequency synthesizer 15 ... Intermediate frequency circuit 15a ... Amplifier 15b ... Band pass filter (BPF)
15c ... mixer 15d ... frequency synthesizer 15e ... A / D converter (A / D)
16 ... Receiver 16a ... Searchers 16b, 16c, 16d ... Finger 16e ... Symbol combiner 17 ... Signal processing unit 100 ... Control unit 200 ... Storage unit 200a ... Path table storage area

Claims (3)

In a mobile radio terminal capable of performing rake reception through a plurality of communication paths from a plurality of base stations, each of which forms a different radio zone, in wireless communication with a base station by a CDMA (Code Division Multiple Access) method,
From the base station, priority information acquisition means for acquiring information indicating priorities respectively assigned in advance to a plurality of wireless zones;
Candidate path number determining means for determining the number of candidate paths for each wireless zone according to the priority of each wireless zone obtained by the priority information acquisition means;
Path detection means for receiving radio signals from each radio zone and detecting paths suitable for reception by the number of candidate paths determined by the candidate path number determination means for each radio zone;
Storage means for storing information on the path detected by the path detection means;
A mobile radio terminal comprising: receiving means for performing rake reception based on path information stored in the storage means. Receiving level detection means for receiving radio signals from a plurality of radio zones and detecting the respective reception levels;
The candidate path number determining means is configured to change each wireless zone according to the priority of each wireless zone obtained by the priority information obtaining means and the reception level of each wireless zone obtained by the reception level detecting means. The mobile radio terminal according to claim 1, wherein the number of candidate paths is determined for each zone. In a mobile radio terminal capable of performing rake reception through a plurality of communication paths from a plurality of base stations, each of which forms a different radio zone, in wireless communication with a base station by a CDMA (Code Division Multiple Access) method,
Reception level detection means for receiving radio signals from a plurality of radio zones and detecting the respective reception levels;
Candidate path number determination means for determining the number of candidate paths for each wireless zone according to the reception level of each wireless zone obtained by the reception level detection means;
Path detection means for receiving radio signals from each radio zone and detecting paths suitable for reception by the number of candidate paths determined by the candidate path number determination means for each radio zone;
Storage means for storing information on the path detected by the path detection means;
A mobile radio terminal comprising: receiving means for performing rake reception based on path information stored in the storage means.

Images