JP4731092B2 - Mobile communication terminal - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mobile communication terminal used in a cellular mobile communication system.
[0002]
[Prior art]
In a cellular mobile communication system, so-called handoff is performed to switch base stations to be synchronized with movement of a mobile communication terminal. In preparation for this handoff, the mobile communication terminal executes cell measurement processing.
[0003]
For example, in a state where synchronization is established with a certain base station, neighboring cell information provided by a broadcast channel is received from this base station. Subsequently, the received power is measured for each cell (hereinafter referred to as a monitor cell) described in the received neighboring cell information, and the measured value of the received power is compared with a threshold value so that each monitor cell is evaluate. The threshold value is set based on the received power value of the synchronization establishment destination cell (hereinafter referred to as an active cell). Then, based on the comparison evaluation result, a cell to be added or exchanged to the active cell is determined, and the determined cell is notified to the base station (see, for example, Non-Patent Document 1).
[0004]
By providing such a function, it becomes possible for the mobile communication terminal to always establish synchronization with the base station of the optimum cell at any time, regardless of whether it is waiting or communicating.
[0005]
[Non-Patent Document 1]
3GPP TS25.331 V3.7.0 (2001-06) 14.Specific function
[0006]
[Problems to be solved by the invention]
However, such a conventional cell measurement processing function has the following problems to be improved. That is, a large number of cells are described in the neighboring cell information generally notified from the base station. The conventional mobile communication terminal performs a comparison evaluation operation with a threshold value after measuring the received power for all the cells specified by the flag as a measurement target among many cells described in the neighboring cell information. .
[0007]
For this reason, when determining a cell to be added or replaced as an active cell, a comparative evaluation calculation process is required for each of the cells, and a microcomputer or a digital signal processing unit (DSP) of the control module is used for this process. : Digital Signal Processor) has an extremely large processing load, which increases the power consumption of the terminal and shortens the battery life.
[0008]
The present invention has been made paying attention to the above circumstances, and its purpose is to reduce the processing load of the control module related to the cell measurement process, thereby reducing the power consumption and extending the battery life. It is to provide a mobile communication terminal .
[0009]
[Means for Solving the Problems]
Mobile communication terminals, a plurality of monitor cell described in the acquired surrounding cell information from the base station, based on the reception quality, the cell within the reception quality number higher constant according to the present invention in order to achieve the above object Are registered in a first category and a second category in which cells not included in the first category are registered . Then, from among the classified categories, only the first category whose reception quality exceeds a predetermined level is selected as an evaluation target , and the second category is excluded from the evaluation target, and the selected first category is selected. Create a list of cells to be evaluated based on the included monitor cells, perform a predetermined evaluation calculation process on the cells included in the created list, and select cells that are candidates for synchronization establishment It is a thing.
[0010]
Therefore, according to the present invention, among the plurality of monitor cells that are notified by the neighboring cell information, a list of cells to be evaluated from the monitor cell for some of the reception quality is classified into the first category of higher creation Thus, the comparative evaluation operation is performed only for the cells of this list. Therefore, among the plurality of monitor cells that are notified by the peripheral cell information, comparative evaluation prior had to perform calculation of the threshold and After measuring the reception power for all the cells specified by the flag as measured Compared to the cell measurement control method, the number of cells subject to comparative evaluation calculation is limited, and the processing load of the control module can be reduced, thereby reducing the power consumption of the terminal and extending the battery life. It becomes possible.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a diagram showing a cell configuration of a cellular mobile communication system according to an embodiment of the present invention.
[0012]
In the service area, a plurality of base stations BS1, BS2,... Are distributed, and these base stations BS1, BS2,... Form radio areas E1, E2,. The mobile communication terminal MS enters a standby state after establishing synchronization with the nearest base station in any of the cells E1, E2,. When an incoming / outgoing call occurs in this standby state, wireless information communication is possible using a dedicated channel (DCH) after establishing a wireless link. As a radio access scheme for connecting the base stations BS1, BS2,... And the mobile communication terminal MS, a CDMA (Code Division Multiple Access) scheme is used.
[0013]
FIG. 2 is a circuit block diagram showing a configuration of the mobile communication terminal MS.
The radio signal transmitted from the base stations BS1, BS2,... Via the dedicated channel is received by the antenna 1 and then input to the radio module RU. The radio module RU includes an antenna duplexer (DUP) 2, a reception circuit (RX) 3, a frequency synthesizer (SYN) 4, and a transmission circuit (TX) 5. The reception circuit 3 mixes the radio signal input via the antenna duplexer (DUP) 2 with the reception local oscillation signal output from the frequency synthesizer 4 and converts the frequency into an intermediate frequency signal. Then, the intermediate frequency signal is orthogonally demodulated and a received baseband signal is output. The frequency of the reception local oscillation signal generated from the frequency synthesizer 4 is indicated by a frequency control signal SYC generated from the main control unit 12.
[0014]
The received baseband signal is input to the CDMA signal processing unit 6 of the baseband unit BU. The CDMA signal processing unit 6 includes a RAKE receiver. In the RAKE receiver, each multipath received signal included in the received baseband signal is despread by a spreading code. The despread multipath received signals are combined in phase after being matched in phase. As a result, received data in a predetermined transmission format is obtained. The received data is separated into control data and user data. The control data is input to the main control unit 12, while the user data is input to the compression / decompression processing unit (hereinafter referred to as compander) 7.
[0015]
The compander 7 separates the user data output from the CDMA signal processing unit 6 for each medium by the demultiplexing unit. Then, the data of each separated medium is decrypted. For example, if audio data is included in user data, the audio data is decoded by a speech codec. If the user data includes video data, the video data is decoded by a video codec.
[0016]
The digital audio signal obtained by the decoding process is input to a PCM (Pulse Code Modulation) code processing unit (hereinafter referred to as a PCM codec) 8, and the digital video signal is input to a main control unit 12. Furthermore, when text data such as e-mail is included in the user data, this text data is input from the compander 7 to the main control unit 12.
[0017]
The PCM codec 8 performs PCM decoding on the digital audio signal output from the compander 7 and outputs an analog audio signal. The analog audio signal is amplified by the receiving amplifier 9 and then output from the speaker 10 as a loud voice.
[0018]
The main control unit 12 displays the digital video signal output from the compander 7 on a liquid crystal display (LCD) of the display unit 15 using a video memory. The main control unit 12 temporarily stores web data downloaded from a site on the Internet and text data such as an e-mail in the received data storage area of the storage unit 16 and displays the data on the LCD. When the answering machine mode is set, the main control unit 12 takes in the audio data and video data before being decoded by the compander 7 and stores these data in the answering machine recording area of the storage unit 16. .
[0019]
On the other hand, the voice signal of the speaker input to the microphone 11 is amplified to an appropriate level by the transmission amplifier 13 and then subjected to PCM encoding processing by the PCM codec 8 to be input to the compander 7 as a digital audio signal. Is done. A video signal captured by a camera (not shown) is digitized by the main control unit 12 and input to the compander 7. Note that text data such as an e-mail created in the main control unit 12 is also input from the main control unit 12 to the compander 7.
[0020]
The compander 7 performs transmission processing of a transmission voice signal according to an AMR (Adaptive Multi Rate) method. That is, the energy amount of the input voice is detected from the digital audio signal output from the PCM codec 8, and the transmission data rate is determined based on the detection result. Then, the digital audio signal is encoded into a signal having a format corresponding to the transmission data rate, thereby generating audio data. The digital video signal output from the main control unit 12 is encoded to generate video data. Then, these audio data and image data are packetized according to a predetermined transmission format by the demultiplexing unit, and this transmission data is output to the CDMA signal processing unit 6. Even when text data such as e-mail is output from the main control unit 12, the text data is multiplexed with the transmission data.
[0021]
The CDMA signal processing unit 6 multiplexes the transmission user data output from the compander 7 and the transmission control data output from the main control unit 12 by performing spread spectrum processing using a spreading code. Then, the multiplexed transmission data is supplied to the transmission circuit (TX) 5 of the wireless module RU. The transmission circuit 5 modulates the transmission data supplied from the CDMA signal processing unit 6 using a digital modulation method such as a QPSK (Quadriphase Phase Shift Keying) method. Then, the transmission signal generated by the digital modulation is combined with a transmission local oscillation signal generated from the frequency synthesizer 4 in accordance with an instruction from the main control unit 12 and frequency-converted into a transmission radio signal. Then, the transmission radio signal is amplified at a high frequency so that the transmission power value instructed by the main control unit 12 is obtained. The amplified transmission radio signal is supplied to the antenna 1 via the antenna duplexer 2 and is transmitted by radio from the antenna 1 to the connected base station.
[0022]
In addition to the dial keys, the input unit 14 is provided with function keys such as a transmission key, an end key, a power key, a volume adjustment key, and a mode designation key. The display unit 15 is provided with an LED (Light Emitting Diode) in addition to the LCD described above. In addition to the transmission / reception video data and mail data, the LCD displays phone book information, the telephone number of the terminal used by the communication partner user, transmission / reception history, the operating state of the terminal itself, and the like. Further, the LED is used for notifying incoming calls and displaying the state of charge of the battery 16. Reference numeral 18 denotes a power supply circuit, which generates a predetermined operating power supply voltage Vcc based on the output of the battery 17 and supplies it to each circuit unit.
[0023]
By the way, the main control unit 12 as a control module includes a microcomputer and a DSP. As a control processing function according to the present invention, a peripheral cell information acquisition function 12a, a category classification function 12b, and an evaluation calculation processing function 12c are provided. Further, the storage unit 16 is provided with a peripheral cell information storage area 16a, a category list storage area 16b, and a detection target list storage area 16c for each control process described above.
[0024]
The neighboring cell information acquisition function 12a causes the wireless unit RU to receive neighboring cell information provided via a broadcast channel from a base station with which synchronization has been established, and the received neighboring cell information is stored in the storage unit 16 as described above. It is stored in the peripheral cell information storage area 16a.
[0025]
The category classification function 12b classifies each cell described in the peripheral cell information acquired by the peripheral cell information acquisition function 12a into a plurality of preset categories and creates a category list. Then, the wireless unit RU is caused to measure the received power value for each cell in each created category list. Then, each category list is updated based on the measurement result. Each updated category list is stored in the category list storage area 16 b in the storage unit 16.
[0026]
The evaluation calculation processing function 12c selects a category list in which cells having higher received power values are registered from each category list created by the category classification function 12b, and selects a detection target cell from the selected category list. Select to create an event detection target list. The event detection target list is composed of an event detection target list for cell addition and an event detection target list for cell replacement. These event detection target lists are stored in a detection target list storage area 16c in the storage unit 16. Is done.
[0027]
Then, the evaluation calculation processing function 12c performs an evaluation calculation for each cell included in the created event detection target list. The evaluation calculation is performed by obtaining a threshold value based on the received power value of the active cell and comparing the received power value of each cell with this threshold value.
[0028]
Next, operations related to cell measurement control by the mobile communication terminal MS configured as described above will be described. 4 to 7 are flowcharts showing the control procedure and control contents.
[0029]
When the neighboring cell information is transmitted from the base station via the broadcast channel in the standby state, the mobile communication terminal MS receives the neighboring cell information by the radio unit RU and then passes through the CDMA signal processing unit 6 to the main control unit 12. And stored in the peripheral cell information storage area 16a of the storage unit 16. For example, as shown in FIG. 3A, the neighboring cell information is a list of a plurality of cells (monitor cells) existing around the mobile communication terminal MS for each radio frequency f1, f2,. Each cell is represented by a cell number and cell information representing a cell attribute. The cell information includes, for example, a detection target flag.
[0030]
Now, when the neighboring cell information is acquired in this way, the mobile communication terminal MS first executes a category classification process with a power measurement process in step 4a by the main control unit 12 as shown in FIG.
[0031]
That is, first, the peripheral cell information is read from the peripheral cell information storage area 16a of the storage unit 16, each monitor cell described in the peripheral cell information is classified into a plurality of categories, and a category list is created. For example, there are the following five categories.
[0032]
(1) Category A category in which cells that are active cells are registered.
(2) A category in which cells changed from the C category or the N category are temporarily registered when the broadcast information of a cell selected as a reselection candidate among the B category monitor cells is acquired with the channel open. Note that the cells registered in the B category are changed again to the A category and the C category after the broadcast information is acquired.
(3) A category in which cells that are not included in the B category and whose received power value is within the upper fixed number are registered among the C category monitor cells.
(4) A category in which cells that are not included in the B category and the C category and whose received power value is within the upper certain number are registered among the N category monitor cells.
(5) A category in which cells that are not included in the C category and the N category are registered among the R category monitor cells.
[0033]
Subsequently, as shown in FIG. 5, the main control unit 12 performs scheduling for power measurement based on the category list in step 5a. In this scheduling, a monitor cell whose detection target flag is set to “valid” is selected. Then, according to the created schedule, a power measurement request for each monitor cell to be measured is given to the wireless unit RU. This power measurement request is made by writing measurement setting information to the DSP in step 5b.
[0034]
The radio unit RU sequentially measures the received power for each monitor cell to be measured in accordance with the power measurement request, and returns the measurement result to the main control unit 12. The main control unit 12 reads the measurement results into the DSP in step 5c, and performs a calculation for converting the read measurement results into power values in step 5d. Then, based on the calculated power value of each cell, the contents of each category list are updated in step 5e. FIG. 3B shows an example of the structure of each updated category list.
[0035]
Next, the main control unit 12 proceeds to step 4b, where an evaluation calculation process is performed for the monitor cell subject to event detection. That is, as shown in FIG. 6, first, in step 6a, a category list including cells with higher power values is selected from each category list stored in the category list storage area 16b of the storage unit 16. For example, a B category list and a C category list are selected. Then, a detection target cell is selected from the selected B category list and C category list to create an event detection target list.
[0036]
As described above, the event detection target list is composed of the cell addition event detection target list and the cell replacement event detection target list. These event detection target lists are stored in the detection target list in the storage unit 16. Stored in area 16c. FIG. 3C shows an example of the configuration.
[0037]
Subsequently, in step 6b, the main control unit 12 determines whether or not a detection target cell exists in each of the detection target lists. If a detection target cell exists, one detection target cell is selected, and a comparative evaluation operation is performed on the selected cell in step 6c. The evaluation calculation is performed by obtaining a threshold value based on the received power value of the active cell and comparing the received power value of each cell with this threshold value. The evaluation formula used for this evaluation calculation is defined in the 3GPP recommendation. For example, 3GPP TS 25.304 is used when waiting and using a common channel (reselection), and 3GPP TS 25.331 is used when using an individual channel.
[0038]
Further, based on the result of the evaluation calculation, the main control unit 12 determines in step 6d whether or not the detection target cell has a condition necessary for adding to or replacing the active cell. As a result of the determination, if the condition is satisfied, the process proceeds to step 6e to set a notification flag for the detection target cell. Then, after updating the cell pointer in step 6f, the process returns to step 6b, and the evaluation calculation process for the next detection target cell is repeated. As a result of the determination in step 6d, if the condition is not provided, the process proceeds to step 6f as it is without setting the notification flag, and after the cell pointer is updated here, the process returns to step 6b.
[0039]
Then, when the evaluation calculation is completed for all the detection target cells described in the cell addition event detection target list and the cell replacement event detection target list, the main control unit 12 performs notification control in step 4c of FIG. Execute. That is, as shown in FIG. 7, first, in step 7a, it is determined whether there is a monitor cell for which a notification flag is set. As a result of the determination, if there is a cell for which the notification flag is set, the process proceeds to step 7b, and the cell number and cell information of the cell for which the notification flag is set are read from the storage unit 16, and this read The cell number and cell information are notified to the base station that is establishing synchronization using the control channel.
[0040]
As described above, in this embodiment, each cell described in the neighboring cell information acquired by the neighboring cell information acquisition function 12a is classified into a plurality of categories by the category classification function 12b based on the received power value. Create a category list for each. Then, among the created category lists, an event detection target list is created by selecting a detection target cell from a category list in which a cell having a higher received power value is registered, and the event detection target list is created. An evaluation operation is performed for each included cell. Then, based on the result of this evaluation calculation, it is determined whether or not the cell satisfies a condition for adding or exchanging to the active cell. If the condition is satisfied, the cell is notified to the base station. I have to.
[0041]
Therefore, according to this embodiment, the detection target cell is selected from the monitor cells classified into the B category and the C category with the higher received power, and the detection target list is created. Only the monitor cells in this detection target list A comparative evaluation calculation process is performed. For this reason, the processing load of the control module can be greatly reduced, thereby reducing the power consumption of the mobile communication terminal MS and extending the battery life.
[0042]
Incidentally, in the conventional cell measurement control method in which comparative evaluation calculation is performed for a large number of cells described in the neighboring cell information, comparative evaluation calculation processing is performed for a maximum of 32 cells. For this reason, the processing load of the control module becomes extremely large, and a large amount of power is consumed for this processing. As a result, shortening of the battery life is inevitable.
[0043]
The present invention is not limited to the above embodiment. For example, in the embodiment, the detection target list is created from the B category list and the C category list. However, when the number of monitor cells classified into the B category list is large, the detection target list is generated only from the B category list. If the number of monitor cells classified into the B category list and the C category list is not sufficient, a monitor cell is selected from the N category list in addition to the B category list and the C category list. Then, the detection target list may be created.
[0044]
In the embodiment, the received power is measured for all the monitor cells notified by the neighboring cell information, and each category list is updated based on the result. However, the present invention is not limited to this, and the received power may be measured only for the monitor cells classified in the upper category list in the category list, and the category list may be updated based on the result. With this configuration, the time required for measuring the received power of the monitor cell can be shortened, and the power consumption in the wireless unit can be reduced.
[0045]
In addition, the circuit configuration of the mobile communication terminal, the configuration of the reception quality detection means, the type of category, the procedure and contents of the category classification process, the procedure and contents of the evaluation calculation process, and the like are variously within the scope of the present invention. It can be implemented with deformation.
[0046]
【The invention's effect】
Above in the present invention as described in detail, first of multiple monitors cell described in the acquired surrounding cell information from the base station, based on the reception quality, reception quality cell within the upper fixed number is registered And a second category in which cells not included in the first category are registered . Then, only the first category whose reception quality exceeds a predetermined level is selected as the evaluation target from among the classified categories , and the second category is excluded from the evaluation target, and the selected first category is selected . A list of cells to be evaluated is created based on the monitor cells included in the category, a predetermined evaluation calculation process is performed on the cells included in the created list, and a cell that is a candidate for synchronization establishment is selected. I am doing so.
[0047]
Therefore, according to the present invention, it is possible to provide a mobile communication terminal that can reduce the processing load of the control module related to the cell measurement process, thereby reducing the power consumption and extending the battery life.
[Brief description of the drawings]
FIG. 1 is a diagram showing a cell configuration of a cellular mobile communication system according to an embodiment of the present invention.
2 is a circuit block diagram showing a configuration of a mobile communication terminal of the mobile communication system shown in FIG.
3 is a diagram showing an example of the configuration of neighboring cell information, a category list, and a detection target list stored in a storage unit in the mobile communication terminal shown in FIG.
4 is a flowchart showing the procedure and contents of cell measurement processing executed by the main control unit of the mobile communication terminal shown in FIG. 2;
FIG. 5 is a flowchart showing the procedure and contents of a category classification process involving a power measurement process executed by the main control unit of the mobile communication terminal shown in FIG. 2;
6 is a flowchart showing the procedure and contents of a comparison determination process executed by the main control unit of the mobile communication terminal shown in FIG.
7 is a flowchart showing the procedure and contents of notification processing executed by the main control unit of the mobile communication terminal shown in FIG. 2;
[Explanation of symbols]
BU ... Baseband unit RU ... Wireless unit 1 ... Antenna 2 ... Duplexer (DUP)
3. Receiving circuit (RX)
4 ... Frequency synthesizer (SYN)
5 ... Transmission circuit (TX)
6 ... CDMA signal processing unit 7 ... compression / decompression processing unit (compander)
8 ... PCM code processor (PCM codec)
DESCRIPTION OF SYMBOLS 9 ... Reception amplifier 10 ... Speaker 11 ... Microphone 12 ... Control part 12a ... Peripheral cell information acquisition function 12b ... Category classification function 12c ... Evaluation calculation processing function 13 ... Transmission amplifier 14 ... Input part 15 ... Display part 16 ... Storage part 16a ... peripheral cell information storage area 16b ... category list storage area 16c ... detection target list storage area 17 ... battery 18 ... power supply circuit 18 ... transmitter amplifier

Claims (2)

In a mobile communication terminal that selects a cell that satisfies a predetermined condition from a plurality of cells formed by a plurality of base stations, and establishes synchronization with the base station that forms the cell,
Obtaining means for obtaining neighboring cell information describing a list of cells existing around the mobile communication terminal of the mobile terminal from the base station;
Based on the acquired neighboring cell information, measuring means for measuring reception quality of signals from base stations constituting a plurality of cells described in the neighboring cell information;
Multiple monitors cell described in the obtained neighboring cell information in accordance with the measurement result of the reception quality, a first category reception quality is registered cell within the top predetermined number, the first category A classifying means for classifying the cells not included in the second category to be registered ;
Only the first category whose reception quality exceeds a predetermined level is selected as an evaluation target from among the classified categories , and the second category is excluded from the evaluation target and included in the selected first category. a list creation means for creating a list of cells to be evaluated on the basis of the only monitor cell,
Cell selection means for performing a predetermined evaluation calculation process on the cells included in the created list and selecting a cell that is a candidate for synchronization establishment based on a result of the evaluation calculation process; Mobile communication terminal. The list creation means selects only the first category whose reception quality exceeds a predetermined level from the classified categories as an evaluation target, excludes the second category from the evaluation target, and selects the selected first category. only to the original monitor cell that is included in the first category, to create an evaluation target list and the evaluation target list for cell replacement for the cell respectively added,
The cell selection means performs predetermined evaluation calculation processing for each of the cells included in the created cell addition evaluation target list and cell replacement evaluation target list, and based on the result of the evaluation calculation processing, synchronization is performed. 2. The mobile communication terminal according to claim 1, wherein a cell to be added to an establishment destination candidate and a cell to be exchanged with an existing synchronization establishment destination candidate are selected.

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