WO2007117025A1

WO2007117025A1 - Mobile communication terminal

Info

Publication number: WO2007117025A1
Application number: PCT/JP2007/057996
Authority: WO
Inventors: Taiga Saegusa; Tetsuya Mishuku; Yuichi Nakai; Sinsuke Uga; Shingo Higuchi; Yoshihiro Yamabe; Masakazu Takahashi; Shuichi Kimura; Tetsuro Takahira; Hiroki Iwai; Masato Maeda; Hiroo Omori
Original assignee: Mitsubishi Electric Corporation; Ntt Docomo, Inc.
Priority date: 2006-04-11
Filing date: 2007-04-11
Publication date: 2007-10-18
Also published as: JPWO2007117025A1; JP4685930B2

Abstract

A mobile communication terminal comprises a received electric field intensity measuring section (12) for measuring the received electric field intensity of a cell and an event 1x judging section (6) for judging addition of a cell to the radio link, deletion of a cell from the radio link, or replacement of the cell according to the measured received electric field intensity. The event 1x judging section (6) judges the addition, deletion, or replacement of the cell with respect to the radio link according to the instantaneous value of received electric field intensity at the time of opening a DCH upon start of communication.

Description

Specification

Mobile communication terminal

Technical field

TECHNICAL FIELD [0001] The present invention relates to a mobile communication terminal, and more particularly to a mobile communication terminal capable of performing cell reselection and node over at an appropriate timing during high-speed movement.

Background art

[0002] As a conventional mobile communication system, there is one disclosed in Patent Document 1, for example. In the system disclosed in Patent Document 1, a mobile communication terminal monitors communicable base stations at predetermined intervals, and stores the received electric field strength of the base station selected by this monitoring as time-series data for each base station. The inclination of the received electric field strength for each base station monitored based on the time series data of the received electric field strength is calculated.

[0003] Then, the mobile communication terminal of Patent Document 1 uses the calculated inclination of the received electric field strength for each base station and the latest received electric field strength value for each base station in the stored time-series data. Based on the above, the base station that can obtain the optimum received field strength is predicted from the monitored base stations. In this way, by predicting a change in received electric field strength with time and selecting a base station at the time of standby, the system of Patent Document 1 can improve the call quality at the time of communication.

Here, a description will be given of operations during transmission and communication of a general mobile communication system. A conventional mobile communication terminal is a base station that covers a standby cell at the start of a call (hereinafter abbreviated as a standby cell). In response, open the FACH (Forward Access CHannel) and measure the received field strength. At this time, if the measured received electric field strength force is a base station capable of cell reselection, cell reselection is performed until DCH (Dedicated CHannel) is opened.

[0005] After the DCH is opened, the conventional mobile communication terminal measures the received electric field strength for the base station and determines an event. Here, the control to control handover between base stations If the received electric field strength satisfies the event occurrence condition for the trigger time (Time To Trigger) (milliseconds) specified by your station, the “Measurement Report” is the search result of the neighboring cells for handover to the base station. To the control station.

[0006] The operation according to the above-described procedure is performed until the DCH is closed. Note that the received electric field strength used for the conventional celery selection and event determination is a value obtained by performing smoothing by a time average within a certain time rather than an instantaneous value.

Patent Document 1: Japanese Patent Laid-Open No. 11 136738

As shown in FIG. 14, at the cell edge of base stations BTS1 and BTS2, the received electric field strength is a weak electric field. In addition, at this cell edge, there is a section where communication with both base stations BTS1 and BTS2 is possible. When the mobile communication terminal enters this section, handover is performed and communication is continued.

[0009] In such a mobile communication system, since the mobile communication terminal is moving with the passage of time, the base station selected at the time of standby at the time of outgoing call and the base station that actually communicates are the same position. However, there is no guarantee that the best base station is selected when performing actual communication.

Similarly, during communication, there is a problem that the received electric field strength of the handover source cell deteriorates during the handover procedure, and communication is interrupted. In particular, during high-speed movement, the received electric field strength may deteriorate rapidly at the cell edge. In this case, the time required for cell reselection or handover is shorter when moving at high speed (see Fig. 15 (b)) than when stationary or at low speed (see Fig. 15 (a)). Failure may occur, resulting in a decrease in transmission rate and deterioration in reception quality.

[0011] As described above, the problem during communication during high-speed movement is that the base station is selected using the amount of time variation of the received electric field strength for a cell that is waiting, that is, a non-communication cell. The system cannot handle it.

[0012] The present invention was made to solve the above-described problems, and a mobile unit that can improve cell rate and communication quality by performing cell reselection and node over at appropriate timing during high-speed movement. The purpose is to obtain a communication terminal. Disclosure of the invention

[0013] A mobile communication terminal according to the present invention is a mobile communication terminal in which one or more connectable cells are selected as a communication partner cell from a plurality of cells served by a plurality of base stations. A reception level measurement unit that measures the reception level of the cell, and an event determination unit that determines addition, deletion, or replacement of the cell to the radio link based on the reception level measured by the reception level measurement unit, When the event determination unit starts communication, it determines whether a cell is added to, deleted from, or replaced with a radio link based on the instantaneous value of the reception level at the time of channel establishment for controlling communication from the base station to its own terminal. It is what you do.

[0014] Thus, when the event determination unit starts communication, the event determination unit determines whether the cell link to the radio link of the cell is based on the instantaneous value of the reception level at the time of channel establishment for controlling communication from the base station to the terminal. Since addition, deletion, or replacement is determined, there is an effect that communication quality can be improved by performing handover at an appropriate timing even when moving at high speed.

Brief Description of Drawings

FIG. 1 is a block diagram showing a configuration of a mobile communication terminal according to Embodiment 1 of the present invention.

FIG. 2 is a graph showing changes in received electric field strength over time in a standby cell and a monitor cell.

FIG. 3 is a flowchart showing the operation up to the end of communication by the mobile communication terminal according to the first embodiment.

FIG. 4 is a graph showing changes in received electric field strength over time in a standby cell and a monitor cell.

FIG. 5 is a flowchart showing the operation up to the end of communication by the mobile communication terminal according to the second embodiment.

FIG. 6 is a flowchart showing operations up to the end of DCH open force communication of the mobile communication terminal according to the third embodiment.

FIG. 7 is a graph showing the change over time of the received electric field strength in the communicating cell and the monitor cell. The

FIG. 8 is a flowchart showing an operation up to the end of DCH open force communication of a mobile communication terminal according to Embodiment 4 of the present invention.

FIG. 9 is a flowchart showing an operation up to the end of DCH open force communication of a mobile communication terminal according to Embodiment 5 of the present invention.

FIG. 10 is a flowchart showing operations up to the end of DCH open force communication of a mobile communication terminal according to Embodiment 6 of the present invention.

FIG. 11 is a flowchart showing an operation up to the end of DCH open force communication of a mobile communication terminal according to Embodiment 7 of the present invention.

FIG. 12 is a flowchart showing the operation until the DCH open power of the mobile communication terminal according to Embodiment 8 of the present invention reaches the end of communication.

FIG. 13 is a flowchart showing the operation until the DCH open force of the mobile communication terminal according to Embodiment 9 of the present invention reaches the end of communication.

FIG. 14 is a conceptual diagram of handover.

[Fig.15] A diagram showing possible sections for handover during stationary, low-speed movement, and high-speed movement.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, in order to explain the present invention in more detail, the best mode for carrying out the present invention will be described with reference to the accompanying drawings.

Embodiment 1.

FIG. 1 is a block diagram showing a configuration of a mobile communication terminal according to Embodiment 1 of the present invention. The mobile communication terminal 1 of the present invention includes an RF unit 3 and a modem unit 4. The RF unit 3 amplifies and frequency-converts the signal received by the antenna 2 and outputs a demodulation signal to the demodulation unit 14, or amplifies the modulation signal from the modulation unit 15 and converts the frequency to output to the antenna 2 To do. The modem unit 4 has a software configuration that is managed and controlled by an operation system (not shown) in the mobile communication terminal 1, and includes a layer 1 (physical layer) processing module, a layer 2 (data link layer) processing module, and a layer. 3 (Network layer) processing module power The wireless control unit 5 is formed by the layer 1 processing module. The wireless control unit 5 includes an event lx determination unit (event determination unit) 6, a time change amount determination unit 7, a celery selection determination unit 8, an approach speed measurement unit (speed measurement unit) 9, a frequency deviation measurement unit 10, It comprises a Doppler shift measurement unit 11, a received electric field strength measurement unit (reception level measurement unit) 12, an uplink transmission power command determination unit (command determination unit) 13, a demodulation unit 14, and a modulation unit 15. Note that these constituent parts are obtained by classifying each processing module of a processing program executed by the processor of the mobile communication terminal 1 which is a computer having a communication function for convenience.

[0018] The event lx determination unit 6 performs event determination for detecting a handover destination cell in communication based on information on received electric field strength, frequency deviation, Doppler shift, or a combination thereof. The time change amount determination unit 7 measures the time change amount of the received electric field strength and determines whether or not the event lx is necessary based on the measured time change amount. The celery selection determination unit 8 performs celery selection determination according to the received electric field strength.

[0019] The approach speed measurement unit 9 sets the speed of the mobile communication terminal to V and sets the IVI to 0 when the angle formed by the straight line connecting the mobile communication terminal and the base station and the moving direction of the mobile communication terminal is 0. The approach speed to the base station represented by cos 0 is calculated. The frequency deviation measuring unit 10 measures the frequency deviation between the base station added to the radio link and the own terminal. The Doppler shift measurement unit 11 measures the Doppler shift of the downlink signal having the base station power.

[0020] The received electric field strength measuring unit 12 measures the received electric field strength (EcZlo), the desired signal received power (RSCP), and the path loss. The uplink transmission power command determination unit 13 holds the uplink transmission power command cumulative value, and determines the base station that is the target of radio link deletion according to the cumulative value. The demodulating unit 14 demodulates the received signal of the antenna 2 input from the RF unit 3, and the frequency deviation measuring unit 10, the Doppler shift measuring unit 11, the received electric field strength measuring unit 12, and the uplink transmission power command determining unit 13 as demodulated signals. Output to. The modulation unit 15 receives and modulates the uplink transmission power command from the uplink transmission power command determination unit 13 and outputs the modulated modulation signal to the RF unit 3.

[0021] It should be noted that in the following description, the relationship between the base station and the “cell” is not particularly specified. In this case, the base station that covers the cell is referred to as a “cell”. The network described later is an external network that is connected to the mobile communication terminal 1 of the present invention through wireless communication, and is connected to a control station that controls handover between W-CDMA base stations. It shall be. This control station controls handover of the terminal 1 according to “Measurement Report” reported from the mobile communication terminal 1.

[0022] Also, for simplicity of explanation, FIG. 1 shows all the unique configurations in the present invention. However, in Embodiment 1, reception is performed immediately after DCH opening with respect to a conventional mobile communication terminal. The reception field strength measuring unit 12 that measures the instantaneous value of the electric field strength and the event lx determination unit 6 that determines the event using the instantaneous value may be added.

Next, the operation will be described.

FIG. 2 is a graph showing the change over time of the received electric field strength between the standby cell and the monitor cell, and FIG. 3 is a flowchart showing the operation until the end of communication of the mobile communication terminal according to the first embodiment. . In the following, the operation will be explained using Figs. 1 to 3 as appropriate.

[0024] First, the mobile communication terminal 1 opens a forward access channel (FACH), which is a DL common channel for control information, to a waiting cell (Serving Cell) at the start of a call (step ST1). The strength measuring unit 12 measures the received field strength of the received signal through the antenna 2 and the demodulating unit 14 through the standby cell and monitor cell power (step ST 2). The process so far corresponds to the start of the communication sequence in FIG. The measured received field strength is output to the celery selection determination unit 8.

[0025] The celery selection determination unit 8 evaluates the monitor cell based on the received electric field strength input from the received electric field strength measurement unit 12, and performs celery selection determination (step ST3). At this time, if the reception level is higher than that of the standby cell, if it is an appropriate monitor cell having “reception level without reception error” as shown in FIG. 2, the process proceeds to step ST4 and the cell is set as the standby cell. If it is not an appropriate cell, the process proceeds to step ST5.

[0026] In step ST5, the mobile communication terminal 1 continues from step ST3 onward until DCH (Dedicated CHannel), which is a channel for transferring user information and control information, is opened. The celery selection determination process is repeatedly executed. The process so far corresponds to the period indicated by the arrow labeled FACH in Fig. 2.

[0027] When the DCH is opened (at the beginning of the period indicated by the arrow labeled DCH in FIG. 2), the received electric field strength measurement unit 12 of the mobile communication terminal 1 communicates via the antenna 2 and the demodulation unit 14. Medium cell power Measure the received field strength of the received downlink signal. At this time, the received electric field strength measuring unit 12 measures the instantaneous value of the received electric field strength immediately after the DCH open, which is not the value obtained by smoothing by the time average within a fixed time, and outputs it to the event lx determining unit 6. . The instantaneous value of the received electric field strength refers to the received electric field strength immediately after the DCH is opened (0 milliseconds).

[0028] The event lx determination unit 6 uses a parameter set different from normal event determination, for example, the instantaneous value of the received electric field strength immediately after DCH opening, and the event determination trigger time (Time To Trigger) is 0 from DCH opening. Under the condition of millisecond, event 1 A is determined for the cell as a target of addition of the radio link (step ST6). As a result, even if the received field strength of the cell in communication immediately deteriorates immediately after the DCH is opened, handover can be performed at a timing before the reception quality deteriorates.

[0029] It should be noted that normal event determination is control specified by 3GPP (3rd Generation Partnership Project), which is an optimal destination (handover destination) cell associated with movement of the mobile communication terminal 1 during communication. It is a process for detecting. The parameter set for normal event determination is a condition for detecting the optimum destination cell, for example, the event determination protection time that is the determination time when adding, deleting, or replacing the monitor cell to the radio link. included.

[0030] In the event determination when the DCH is opened according to the first embodiment, the determination threshold (starting event determination) is shorter than the normal event determination described above, for example, and lower in the determination protection time according to the instantaneous value of the received electric field strength. Set the received electric field strength threshold). That is, in the first embodiment, considering the mobile communication terminal 1 moving at high speed, the event determination immediately after the DCH opening is shortened, and the parameter for shifting to the event determination for the next cell as soon as possible Set.

[0031] If an event indicating that the optimum destination cell has been detected in this determination occurs, the event lx determination Fixed section 6 is the “Measurement Report (Event 1A)” for making the cell a node destination for the network (control station connected to the network). Is transmitted to the network side as a layer 3 message via the RF unit 3 and the antenna 2 (step ST7).

[0032] As described above, by using an instantaneous value of the received electric field strength for event determination immediately after the DCH is opened, it is possible to cope with a sudden change in reception level when moving at high speed or when there are many cells. It becomes possible. In other words, by using a parameter set that can respond to sudden reception level fluctuations in the standby cell, the responsiveness can be accelerated even when the reception level drops rapidly during high-speed movement as shown in Fig. 15 (b). be able to.

[0033] After transmitting "Measurement Report (Event 1A)" or when "Measurement Report (Event 1A)" is not transmitted, the operation shifts to the normal operation when DCH is open. That is, the reception electric field strength measurement unit 12 of the mobile communication terminal 1 measures the reception electric field strength (value obtained by performing smoothing by time average within a predetermined time) for the above-described cell (step ST8). And output to the event lx determination unit 6.

[0034] Similar to normal event determination, the event lx determination unit 6 receives the monitor cell's received electric field strength force S event generation condition for the trigger time (Time To Trigger) (ms) specified from the network side according to 3GPP. Event 1A is determined based on whether or not the power satisfies the condition (step ST9). At this time, if the received electric field strength of the cell satisfies the above condition, “Measurement Report (Event 1 A)”, which is a neighbor cell search result for adding the cell to the radio link (Radio Link: RL), is displayed. Transmit to the network side (step ST10).

[0035] After sending “Measurement Report (Event 1A)” or when “Measurement Report (Event 1 A)” is sent, the event lx determination unit 6 is designated by the network side as described above. During the trigger time (Time To Trigger) (milliseconds), the event 1B is judged based on whether or not there is a cell having the received electric field strength that satisfies the event 1B generation condition (step ST1 Do). If there is a cell that satisfies the above event 1B occurrence condition, a “Measur ement Report (Event IB)” that is a result of searching for neighboring cells that are subject to deletion from the radio link is transmitted to the network side (step ST12). ).

[0036] Further, after sending "Measurement Report (Event IB)" or "Measurement Report ( If the event IB) is not transmitted successfully, the event lx determination unit 6 also performs the event 1C occurrence condition for the specified trigger time (Time To Trigger) (milliseconds) as described above. Event 1C is determined based on whether there is a cell with a received field strength that satisfies the conditions (step ST13). At this time, if there is a cell whose reception electric field strength satisfies the event 1C occurrence condition, the “Measurement Report (Event 1C)” that is the result of the peripheral cell search for replacing the cell with the radio link is sent to the network side. (Step ST14).

[0037] The above-described operations from step ST8 to step ST14 are performed until the DCH is closed. When DCH is closed (step ST15), communication with the cell in communication is terminated.

[0038] As described above, according to the first embodiment, in addition to the conventional handover event determination, the instantaneous value of the received electric field strength immediately after the DCH opening, which is different from the normal event determination at the time of DCH opening, Event determination is performed using a parameter set including a determination protection time and a determination threshold. As a result, even if the reception field strength suddenly deteriorates immediately after the DCH is opened, it is possible to perform a handover at an appropriate timing before the reception quality deteriorates. It is possible to improve quality.

[0039] Embodiment 2.

In the second embodiment, celery selection determination is performed using the instantaneous value of the received electric field strength immediately after the FACH is opened, and if celery selection is possible, the celery selection is stopped and celery selection is performed. Is to continue.

[0040] The basic configuration of the mobile communication terminal according to the second embodiment is the same as that shown in FIG. 1 of the first embodiment. The force cell reselection determining unit 8 and the received electric field strength measuring unit 12 The difference is that celery selection determination using the instantaneous value of the received field strength is performed immediately after the FACH is opened. For simplicity of explanation, FIG. 1 shows all the specific configurations of the present invention. However, the second embodiment is a reception electric field that functions as described above with respect to a conventional mobile communication terminal. A configuration in which only the strength measurement unit 12 and the celery selection determination unit 8 are added may be used. Next, the operation will be described.

FIG. 4 is a graph showing temporal changes in the received electric field strength of the standby cell and the monitor cell, and FIG. 5 is a flowchart showing the operation up to the end of the call start power communication of the mobile communication terminal according to the second embodiment. . In the following, we will explain the operation using Figure 1, Figure 4 and Figure 5 as appropriate.

[0042] First, mobile communication terminal 1 opens FACH for a standby cell at the start of a call (step STla). The received electric field strength measuring unit 12 measures the received electric field strength of the signal that has also received the standby cell and monitor cell forces via the antenna 2 and the demodulator 14 (step ST2a). At this time, the instantaneous value of the received field strength immediately after the FACH is opened is measured. Note that the instantaneous value of the received electric field strength is within the period until the signal of RACH (Random Access CHannel), which is the first UL common channel for control information, is sent immediately after the FACH is opened (a period of less than about 100 milliseconds). Of the received electric field. The instantaneous value of the received electric field strength measured by the received electric field strength measuring unit 12 is output to the celery selection determining unit 8.

[0043] The cell reselection determination unit 8 evaluates the monitor cell and performs cell reselection determination (CR determination) based on the instantaneous value of the received electric field strength input from the received electric field strength measurement unit 12 (step ST3a). . At this time, if the reception level is higher than that of the standby cell and the monitor cell is an appropriate monitor cell having the “reception level without reception error” as shown in FIG. 4, the transmission sequence is stopped (step ST4a ), Cell reselection of the appropriate cell as a standby cell (step ST5a), and restart the transmission sequence (step ST6a)

[0044] In this way, when there is a monitor cell with a better received field strength than the standby cell immediately after the FACH is opened, cell reselection is immediately performed using the FACH open command as a trigger, so that the received field strength during standby can be reduced. When the FACH is open when the measurement period is long, the received field strength is not the best and it is possible to prevent a call from being made in the cell, and it is possible to determine cell reselection using the latest cell level. In addition, by using an instantaneous value as the received electric field strength for cell reselection determination, it is possible to cope with a rapid change in reception level when moving at high speed or when there are many cells. [0045] On the other hand, the received electric field strength measurement unit 12 determines whether there is no cell reselection in step ST3a or after reselecting cell reselection in step ST5a and restarting the transmission sequence in step ST6a. Measure the received electric field strength (step ST7a). Here, similarly to the normal celery selection determination stipulated in 3GPP, a value obtained by performing smoothing by a time average within a certain time as the received electric field strength is measured and output to the celery selection determination unit 8.

[0046] The celery selection determination unit 8 evaluates the monitor cell based on the received electric field strength input from the received electric field strength measurement unit 12, and performs celery selection determination (step ST8a). At this time, if the reception level is higher than that of the standby cell and the monitor cell is an appropriate monitor cell having the “reception level without reception error” as shown in FIG. 4, the process proceeds to step ST9a to wait for that cell. Cell reselection is performed as a cell, and if it is not an appropriate cell, the process proceeds to step STIOa.

[0047] In step STIOa, the mobile communication terminal 1 repeats the cell reselection determination process from step ST7a to step ST9a until DCH (Dedicated CHannel), which is a channel for transferring user information and control information, is opened. Execute. The process so far corresponds to the period indicated by the arrow marked FACH in Fig. 4 (the period until the communication sequence start force DCH opens).

[0048] When the DCH is opened, the reception field strength measurement unit 12 measures the reception field strength of the downlink signal received from the cell in communication via the antenna 2 and the demodulation unit 14 (step ST1 la), and determines the event lx Output to part 6. This received field strength is measured by smoothing the signal by averaging the time within a certain period of time as in the normal DCH open process specified by 3GPP.

[0049] In the event lx determination unit 6, as in the normal event determination stipulated in 3GPP, the received electric field strength is increased by the specified trigger time (Time To Trigger) (milliseconds). Event 1A is determined based on whether or not the force satisfies the generation condition (step ST12a). At this time, if the received electric field strength of the monitor cell satisfies the above condition, a “Measurement Report (Event 1A)” that is a search result of a neighboring cell in which the cell is an addition target of the radio link is transmitted to the network side (step ST13a). ). [0050] Hereinafter, as in the first embodiment, until the DCH is closed, the determination of the event 1A, the event IB and the event 1C related to the radio link deletion and the radio link replacement is performed from the step ST1 la to the step ST1 la. The processing up to ST17a is repeated. When the DCH is closed (step ST18a), the communication with the cell in communication ends as described above.

[0051] Note that celery selection can be performed only in the FACH section, but conventionally, the transmission sequence proceeds before celery selection is completed, and the FACH is closed and the DCH may be opened. Therefore, in the second embodiment, during cell reselection, transmission in a cell with good reception quality can be performed by preferentially performing cell reselection by stopping the transmission sequence in the FA CH section.

[0052] As described above, according to the second embodiment, when an instantaneous value of the received electric field strength immediately after opening the FACH is used and there is a monitor cell having a better received electric field strength than the standby cell when the FACH is opened, Cell reselection is performed immediately using the FACH open command as a trigger, and at the start of the transmission sequence, it is possible to suppress the transmission sequence from being delayed due to the deterioration of the reception field strength of the standby cell, resulting in transmission failure. As a result, it is possible to avoid a call in a state where the received electric field strength is bad, and the call rate can be improved.

[0053] Embodiment 3.

In the third embodiment, the time change amount of the received electric field strength of the monitor cell is calculated after the DCH is opened, and this time change amount is used as an event report index.

[0054] The basic configuration of the mobile communication terminal according to the third embodiment is the same as that shown in Fig. 1 of the first embodiment described above. The difference is that event judgment is performed using the time variation of received electric field strength after H-open. For the sake of simplicity, FIG. 1 shows all the specific configurations in the present invention V, but the received field strength is measured before the received field strength measurement after DCH opening for a conventional mobile communication terminal. The time change amount determining unit 7 for calculating the time change amount and the event lx determining unit 6 for determining an event using the time change amount may be added.

Next, the operation will be described. Fig. 6 is a flowchart showing the operation up to the end of DCH open force communication of the mobile communication terminal according to the third embodiment, and Fig. 7 is a graph showing the time variation of the received electric field strength in the communicating cell and the monitor cell. FIG. 7 (a) shows the case of a conventional mobile communication system, and FIG. 7 (b) shows the case according to the third embodiment. Hereinafter, the operation will be described with reference to FIGS. 1, 6 and 7 as appropriate.

[0056] When the DCH opens (step STlb) and shifts to the communication state, the received electric field strength measuring unit 12 measures the received electric field strength of the received signal through the antenna 2 and the demodulating unit 14, and changes over time. Output to the quantity judgment unit 7. The time variation determining unit 7 calculates the time variation of the received electric field strength of the monitor cell input from the received electric field strength measuring unit 12, and determines whether or not the calculation result exceeds a threshold regarding the time variation of the received electric field strength. To do. Here, when the threshold value is exceeded or when the force is exceeded, the event lx determination unit 6 is notified accordingly.

[0057] In step ST2b, when the event lx determination unit 6 receives notification from the time change amount determination unit 7 that the threshold has been exceeded, the event lx determination unit 6 proceeds to step ST3b and adds the monitor cell to the radio link, or the monitor cell Send an event (event 1 AZ1C) to switch to a wireless link to the network side (event 1AZ1C). In addition, when receiving a notification that the threshold value is not exceeded in step ST2b, the event lx determination unit 6 does not report the event, and shifts to a state waiting for input of the received electric field strength from the received electric field strength measuring unit 12. At this time, the received electric field strength measurement unit 12 receives the received electric field strength (value obtained by performing smoothing by time average within a certain time) for the communicating cell and the monitor cell as in the conventional case, as in the normal operation during communication. Is measured (step ST4b) and output to the event lx determination unit 6.

[0058] As in the case of normal event determination, the event lx determination unit 6 has a cell with a received electric field strength that satisfies the event generation condition for a trigger time (Time To Trigger) (milliseconds) specified by the network side. Event 1A is determined based on whether or not there is (step ST5b). At this time, if there is a cell whose received electric field strength satisfies the above condition, a “Measurement Report (Event 1A)” that is a result of a peripheral senor search for the cell as an additional target of the radio link is transmitted to the network side (step ST6b).

[0059] After sending "Measurement Report (Event 1A)" or "Measurement Report (Event When the transmission of “1 A)” fails, the event lx determination unit 6 determines the occurrence condition of event 1B for the trigger time (Time To Trigger) (milliseconds) specified from the network side as described above. Event 1B is determined based on whether or not the cell of the received electric field strength that satisfies the power is present (step ST7 b). At this time, if there is a cell whose received electric field strength satisfies the above condition, “Measurement Report”, which is a result of searching for neighboring cells that are to be deleted from the wireless link, is transmitted to the network side (event 1B). (Step ST8b).

[0060] Furthermore, after sending a “Measurement Report (Event IB)” or when “Measurement Report (Event IB)” is sent, the event lx determination unit 6 specifies the network side as well as the above. During the specified trigger time (Time To Trigger) (milliseconds), the event 1C is determined based on whether or not there is a cell having a received electric field strength that satisfies the event 1C generation condition (step ST9b). At this time, if there is a cell whose reception electric field strength satisfies the event 1C occurrence condition, a “Measurement Report”, which is a result of a neighbor cell search for a cell that satisfies the above condition as a replacement target, is transmitted to the network side. (Event 1C) (Step ST10b).

[0061] The above-described operation is performed until the DCH is closed (step ST1 lb). Communication ends when DCH is closed. As described above, in the third embodiment, the amount of time change of the received electric field strength of the monitor cell is always calculated in the communication state, and when the amount of time change of the received electric field strength exceeds the threshold, An event report for switching the wireless link is made, and after the event report is executed and when the event report is weak, the operation shifts to the normal operation during communication.

[0062] As shown in Fig. 7 (a), in the conventional event report, the received electric field strength (EcZ Io) of the monitor cell is the reporting range (dB) (Fig. If the upper limit of the received electric field strength range with the symbol A is exceeded and the communication status continues for the trigger time (Time To Trigger) (seconds) (the period with the symbol B in the figure), an event report is issued. It was done.

In contrast to this, in Embodiment 3, as shown in FIG. 7 (b), the received electric field strength of the monitor cell is measured, and the time variation (= A EcZloZ At) of the received electric field strength is a threshold value. An event report is made when the number is exceeded. In this way, the time variation of the received electric field strength of the monitor cell is calculated By doing so, it is possible to detect a cell whose reception field strength suddenly improves as in the case of the monitor cell in FIG. 7 (b).

[0064] Also, for example, as shown in Fig. 7 (b), assuming that the received electric field strength changes linearly with time, the slope value can be obtained without waiting for the event determination trigger time as in the prior art. It is possible to perform event determination based on (time change amount), and it is possible to report events for addition and replacement of radio links at an earlier timing than before. As a result, the number of communication interruptions can be reduced and communication quality can be improved.

[0065] In the third embodiment, an example is shown in which an event is determined based on the amount of time change in the received electric field strength of the monitor cell. You may use the amount of time change of the received electric field strength of the cell in communication, not the amount. In this case, it is used to detect a sudden deterioration of the cell in communication, and when the amount of time change in the received electric field strength of the cell in communication exceeds the threshold, the addition of a radio link or the replacement of a radio link is performed. Will report.

[0066] As described above, according to the third embodiment, since the event determination is performed by measuring the amount of change in the received electric field strength over time, the cell in which the received electric field strength rapidly increases or rapidly deteriorates. The cell detection timing becomes earlier, and a cell with good reception quality can be added to the radio link target earlier than when adding a normal monitor cell to the radio link, and stable communication quality can be maintained. it can.

[0067] Also, in Embodiment 3 described above, the received field strength is drastically increased by calculating the time change amount of the received field strength of the monitor cell and Z or the cell in communication, and determining the event based on this calculation result. It is possible to detect cells that become better and Z or deteriorated cells, and it is possible to report events of addition and replacement of monitor cells to the radio link at an earlier timing than before. As a result, the number of communication interruptions can be reduced, and communication quality can be improved.

Embodiment 4.

In the fourth embodiment, the approach speed between the mobile communication terminal and the base station is measured, and the base station approaching with the movement of the mobile communication terminal is set as the addition target of the radio link. The cell to be deleted is a radio link deletion target. [0069] It should be noted that the approach speed is V when the speed of the mobile communication terminal is V, and Θ is the angle formed by the straight line connecting the mobile communication terminal and the base station and the moving direction of the mobile communication terminal. V | cos is the value represented by 0. In this case, the direction in which the mobile communication terminal approaches the base station is positive, and the direction in which the mobile communication terminal moves away is negative.

[0070] The basic configuration of the mobile communication terminal according to the fourth embodiment is the same as that shown in FIG. 1 of the first embodiment, except that the approach speed measuring unit 9 and the event lx determining unit 6 The difference is that event determination is performed by predicting the reception level of the cell using the approach speed in addition to the measurement of the received electric field strength. The approach speed measurement unit 9 may calculate the speed of movement of the mobile communication terminal in the direction of the base station as the approach speed using the position information of the mobile communication terminal 1 and the base station location information by GPS. The result of estimating the moving speed of the mobile communication terminal 1 in the direction of the base station based on the Doppler frequency estimation result of the downlink signal from the base station may be used as the approach speed.

[0071] For simplicity of explanation, FIG. 1 shows all the unique configurations of the present invention. However, event determination is performed using the approach speed measuring unit 9 and the approach speed for a conventional mobile communication terminal. Event lx determination unit 6 may be added.

[0072] Further, as an example of cell reception level prediction using the moving speed in the direction of the base station, when there are a plurality of cells having the same reception field strength, priority is given to a base station with a high access speed. For example, it is possible to determine whether to add or delete a radio link based only on the sign of the approach speed, or to change the event judgment meter according to the approach speed. In this way, in addition to the measurement of the received electric field strength, the reception level of the cell is predicted using the approach speed of the mobile communication terminal 1 to the base station, and the result of adding and deleting the radio link using this result Communication quality can be improved by performing the determination.

Next, the operation will be described.

FIG. 8 is a flowchart showing the operation up to the end of DCH open power communication (end call) of the mobile communication terminal according to Embodiment 4 of the present invention. Hereinafter, the operation will be described using FIGS. 1 and 8 as appropriate.

[0074] When the DCH is opened (step STlc) and shifts to the communication state, the approach speed measurement unit 9 acquires the location information of the terminal 1 and the base station location information by GPS (not shown), for example. Then, the relative movement speed of the terminal 1 in the direction of the base station is calculated as an approach speed (step ST 2c) and output to the event lx determination unit 6. Further, the moving speed of the terminal 1 in the direction of the base station may be estimated based on the Doppler frequency estimation result of the downlink signal from the base station, and the approaching speed to the base station may be used.

[0075] Next, reception field strength measurement section 12 measures the reception field strength of the signal received from the monitor cell via antenna 2 and demodulation section 14 (step ST3c), and outputs it to event lx determination section 6 . In the event lx determination unit 6, when the approach speed from the approach speed measurement unit 9 and the reception field strength from the reception field strength measurement unit 12 are input, the event 1A is first determined based on the reception field strength (step ST4c). At this time, the number of radio links that can be set by the terminal itself can be added to the radio link, and the received field strength of the processing target monitor cell is greater than or equal to the received field strength that should report the occurrence of event 1A. If there is, “Measurement Report (Event 1 A)”, which is the result of searching for neighboring cells for which the cell is to be added as a radio link, is transmitted to the network side (step ST6c).

[0076] On the other hand, even if the event lx determination unit 6 determines that event 1A has not occurred in step ST4c, the event lx determination unit 6 proceeds to the process of step ST5c and determines the event 1A based on the approach speed! Make a decision. For example, if the approach speed of the monitor cell to the base station is greater than a predetermined threshold (additional acceleration threshold), the process proceeds to step ST6c, and the measurement report (event 1A) that sets the cell as a target for additional radio link "To the network side.

[0077] In addition, after sending "Measurement Report (Event 1A)" or when "Measurement Report (Event 1A)" is sent, the event lx determination unit 6 uses the trigger time specified from the network side ( During Time To Trigger) (milliseconds), event 1B is determined based on whether or not there is a cell with a received field strength that satisfies the event generation condition (step ST7c). At this time, if there is a cell whose reception electric field strength satisfies the event 1B occurrence condition, a “Measurement Report (Event IB)” that is a search result of a neighboring cell for which the cell is to be deleted from the radio link is transmitted to the network side. (Step ST9c).

[0078] Even if it is determined in step ST7c that event IB has not occurred, event lx determination unit 6 proceeds to the process of step ST8c and determines event 1B based on the approach speed. For example, the radio link power cell can be deleted and the monitor cell base If there is a cell whose access speed to the station is less than a predetermined threshold (deletion speed threshold), the process proceeds to step ST9c, and the measurement report (event) IB) ”to the network side.

[0079] After sending “Measurement Report (Event IB)” or when “Measurement Report (Event 1 B)” is not sent, the event lx judgment unit 6 uses the specified trigger time (Time To Trigger). ) Event 1C is determined based on whether or not there is a cell having a received electric field strength that satisfies the event occurrence condition for (milliseconds) (step ST10c). At this time, if there is a cell whose received electric field strength satisfies the above-mentioned event 1C occurrence condition, a “Measurement Report (Event 1C)” that is a search result of surrounding cells that replace the cell satisfying this condition with the radio link is displayed on the network. (Step ST12c).

[0080] On the other hand, even if it is determined in step STIOc that event 1C has not occurred, event lx determination unit 6 proceeds to the processing of step STl lc and determines event 1 C based on the approach speed. Do. For example, the number of radio links can be switched to a radio link, and the proximity speed that is the moving speed of the terminal 1 toward the base station relative to the base station of the monitor cell is used to replace the existing cell as a radio link. If there is a base station that is larger than the predetermined threshold (replacement / additional speed threshold) and whose approach speed is less than the predetermined threshold (replacement / deletion speed threshold), the process proceeds to step ST12c, and no additional target cell exists. Send “Measurement Report (Event 1C)”, which is the search result of neighboring cells to be switched to the line link, to the network side.

[0081] The above-described operation is performed until the DCH is closed (step ST13c). Communication ends when DCH is closed.

[0082] As described above, according to the fourth embodiment, in addition to the measurement of the received electric field strength, the speed (approach speed) at which the mobile communication terminal 1 approaches or moves away from the base station is used. Then, the reception level of the cell is predicted, and an event is determined using this result, and the radio link is added and deleted by the monitor cell, so communication in a cell with relatively good communication quality becomes possible. A stable communication state can be maintained.

[0083] Embodiment 5.

In the fifth embodiment, there is no base station that does not follow the transmission power requested by the mobile communication terminal. The line link is to be deleted. When the followability of the downlink transmission power control command transmitted from the mobile communication terminal 1 to the base station is poor, it is considered that the reception quality of the uplink signal to the base station also deteriorates. Therefore, in Embodiment 5, in addition to the measurement of the received electric field strength, communication quality is improved by deleting the radio link of the base station that does not follow the downward transmission power control command.

[0084] The basic configuration of the mobile communication terminal according to the fifth embodiment is the same as that shown in FIG. 1 of the first embodiment. The transmission power requested by the own terminal 1 by the force event lx determination unit 6 The difference is that the event for which the cell is to be deleted from the radio link is determined depending on whether it is capable of following the power. For the sake of simplicity, FIG. 1 shows all the unique configurations in the present invention, but the fifth embodiment is an event that performs event determination as described above for a conventional mobile communication terminal. It may be configured to add only the function of lx determination unit 6.

FIG. 9 is a flowchart showing the operation up to the end of DCH open power communication (end call) of the mobile communication terminal according to Embodiment 5 of the present invention. In the following, the operation will be described using FIGS. 1 and 9 as appropriate.

When the DCH is opened (step STld) and transitions to the communication state, the event lx determination unit 6 sets the number of base stations to n, sets i = l to n for each base station, and requests its own terminal 1 The event for which the cell is to be deleted from the radio link is determined according to whether or not it can follow the transmission power.

[0086] First, the event lx determination unit 6 receives a signal received from the base station via the DPCH (Dedicated Physical CHannel) by the terminal 1 for the base station corresponding to i = l (step ST2d). From the power (BTS (l) —downlink DPCH received power), the received power of the downlink signal corresponding to the downlink transmission power control command transmitted to the base station BTS (l) one slot before (BTS (1 slot before BTS ( 1) —Downlink DPCH reception power) is subtracted to obtain the difference BTS (1) —Downlink DPCH reception slot power difference (step ST3d).

[0087] Subsequently, the event lx determination unit 6 compares the obtained BTS (1) —downlink DPCH reception slot power difference with the downlink transmission power control command transmitted to the base station BTS (1). ST4d). At this time, if power does not match the power difference according to the command, The downlink TPC (Transmit Power Control) tracking index for the base station BTS (l) is decreased (step ST5d). The downlink TPC tracking index is a value indicating the degree of tracking of the transmission power requested by the terminal 1 from the base station.

[0088] When the power difference by the above command matches, or after decreasing the TPC tracking index, the event lx determination unit 6 determines whether or not the parameter i is the power of the number of radio links n (step ST6d) If i has not reached n, i is counted (step ST7d), and the processing from step ST3d is repeated.

Thus, in the fifth embodiment, for each base station BTS (i) (i = l to n) that is wirelessly linked, the inter-slot difference in the received power of the downlink dedicated CH and the base station BTS ( The downlink transmission power control command transmitted in i) is compared in multiple frame periods (for example, decoding period), and if they do not match, the downlink TPC tracking index is decreased.

[0090] When the parameter i reaches the number of radio links n, the reception field strength measurement unit 12 measures the reception field strength of the signal that also received the monitor cell force via the antenna 2 and the demodulation unit 14 (step ST8d), and the event Output to lx determination unit 6. Event lx determination unit 6 determines event 1 A based on the received electric field strength (step ST9d). At this time, if the received electric field strength of the monitor cell to be processed is equal to or higher than the received electric field strength to be reported, an “Measurement Report (Event 1A)” is sent to the network side with the cell as the addition target of the radio link. (Step STIOd).

[0091] After sending “Measurement Report (Event 1A)” or when “Measurement Report (Event 1 A)” is sent, the event lx decision unit 6 sets the trigger time (Time To (Trigger) (milliseconds), event 1B is determined based on whether or not there is a cell having a reception field strength that satisfies the event generation condition (step STl ld). At this time, if there is a cell whose received electric field strength satisfies the above-mentioned event 1B occurrence condition, a “Measurement Report (Event IB)”, which is the result of searching for neighboring cells that are to be deleted from the radio link, is sent to the network. (Step ST13d).

[0092] On the other hand, even if event 1x determination unit 6 determines that event 1B has not occurred in step ST1 Id, event lx determination unit 6 proceeds to the processing of step ST12d and determines event 1B based on the downlink TPC tracking index. Do. For example, it is possible to delete a radio link power cell and If the downlink TPC follow-up index of the base station of the target monitor cell is equal to or less than the predetermined threshold, the process moves to step ST13d, and the `` Measurement Report (Event IB) ”is sent to the network side.

[0093] After sending "Measurement Report (Event IB)" or when "Measurement Report (Event IB)" has not been sent, the event lx determination unit 6 is designated from the network side as described above. During the trigger time (Time To Trigger) (milliseconds), event 1C is determined based on whether or not there is a cell having a received electric field strength that satisfies the event generation condition (step ST14d). At this time, if there is a cell whose received electric field strength satisfies the above condition, a “Measurement Report (Event 1C)”, which is a result of a peripheral cell search for the cell as a target for wireless link replacement, is transmitted to the network side (step ST16d).

On the other hand, even if it is determined that event 1C has not occurred, event lx determination unit 6 proceeds to the process of step ST15d and determines event 1C based on the downlink TPC tracking index. For example, when there is a cell whose radio link can be switched based on a predetermined number of radio links and whose downlink TPC tracking index is equal to or less than a predetermined threshold, the mobile terminal shifts to step ST1 6d to perform downlink TPC tracking. Instead of a cell whose index is less than or equal to a predetermined threshold, a measurement report (event 1C), which is a result of a peripheral cell search for a cell whose received electric field strength does not satisfy the above conditions, is to be replaced. Send to the network side.

[0095] The processing from step ST2d to step ST16d described above is performed until the DCH is closed (step ST17d). Communication ends when DCH is closed. In this way, even when event 1B and event 1C do not occur in event determination based on received electric field strength, if the downlink TPC tracking index is below the threshold, it is determined that the base station does not follow the TPC command. However, event 1B and event 1C are generated by making it a target of deletion from the radio link.

[0096] As described above, according to the fifth embodiment, the reception state of the uplink signal to the base station is estimated by the followability of the downlink transmission power control command transmitted from the mobile communication terminal 1 to the base station. Therefore, the monitor cell of the base station, which is considered to have poor tracking performance and poor reception quality, is eliminated. It can be deleted from the line link, and communication quality can be improved.

[0097] Embodiment 6.

In the sixth embodiment, a base station that does not follow FBI (FeedBack Information) requested by a mobile communication terminal is targeted for deletion of the radio link strength. If the mobile communication terminal 1 has good follow-up to the FBI transmitted to the base station, it can be estimated that the reception quality of the uplink signal to this base station is not good. Therefore, in Embodiment 6, the communication quality is improved by deleting the radio link of the base station that does not follow the FBI in consideration of the measurement of the received field strength.

[0098] The basic configuration of the mobile communication terminal according to the sixth embodiment is the same as the FBI requested by the own terminal 1 by the force event lx determination unit 6 which is the same as that shown in FIG. The difference is that the event for which the cell is subject to deletion of the radio link power is determined according to whether or not the power to follow. For simplicity of explanation, FIG. 1 shows all the unique configurations in the present invention, but the sixth embodiment performs event determination as described above for a conventional mobile communication terminal. The configuration may be such that only the function of the event lx determination unit 6 is added.

[0099] FIG. 10 is a flowchart showing the operation up to the end of DCH open power communication (end call) of the mobile communication terminal according to Embodiment 6 of the present invention. Hereinafter, the operation will be described using FIGS. 1 and 10 as appropriate. In the following description, the base station has two antennas A and B for downlink transmission diversity, and the signals transmitted from the antennas A and B are received after being combined on the mobile communication terminal 1 side. In order to increase the power, the phase angle of the common channel and the dedicated channel of antenna B is estimated in mobile communication terminal 1, and as a result, according to the FBI notified from mobile communication terminal 1, antenna B's It is assumed that the TxDiv Closed Loop Model that controls the phase angle of the individual channel with respect to the common channel is applied.

[0100] When the DCH opens (step STle) and shifts to the communication state, the event lx determination unit 6 sets the number of base stations with radio links to n, and sets each base station i = l to n Then, depending on whether or not the terminal 1 follows the FBI requested by the terminal 1, an event for deleting the cell from the radio link is determined.

[0101] Here, the event lx determination unit 6 determines that the communication base station BTS (l) corresponding to i = l Step ST2e), the phase angle (phase difference 0) between the common channel of antenna B of antenna B and the downlink dedicated channel of antenna B (phase difference 0) and the phase angle of the common channel and dedicated channel of antenna B of base station BTS (1) The command (FBI) instructed to) is compared at multiple frame periods (step ST3e). At this time, if the phase angle does not coincide with the command, the FBI tracking index for the base station BTS (1) is decreased (step ST4e). The FBI tracking index may be a value indicating the degree of tracking to the FBI requested by the terminal 1 from the base station.

[0102] When the phase angle by the above command coincides, or after the FBI tracking index is decreased, the event lx determination unit 6 determines whether or not the norm i is the number of radio links n (step ST5e) If i has not reached n, add i (step ST6e) and repeat the process from step ST3e.

Thus, in the sixth embodiment, a plurality of FBI commands for each base station BTS (i) (i = l to n) and the phase angle of the common channel of antenna B and the downlink dedicated channel of antenna B are plural. Compare with the frame period (eg, decoding period), and if the two do not match, decrease the FBI tracking index.

[0103] When the parameter i reaches the number of radio links n, the reception field strength measurement unit 12 measures the reception field strength of the signal that also received the monitor cell power via the antenna 2 and the demodulation unit 14 (step ST7e), and the event Output to lx determination unit 6. Event lx determination unit 6 determines event 1 A based on the received electric field strength (step ST8e). At this time, if the received electric field strength of the monitor cell to be processed is equal to or higher than the received electric field strength to be reported, an “Measurement Report (Event 1A)” is sent to the network side with the cell as the addition target of the radio link. (Step ST9e).

[0104] After sending "Measurement Report (Event 1A)" or when "Measurement Report (Event 1 A)" is not sent, the event lx determination unit 6 sets the trigger time (Time To Trigger) (milliseconds), event 1B is determined based on whether or not there is a cell with a reception field strength that satisfies the event generation condition (step ST10e). At this time, if there is a cell whose received electric field strength satisfies the above conditions, a “Measurement Report (Event IB)” that is a result of searching for a neighboring cell whose radio link power is to be deleted is transmitted to the network side. (Step ST12e). [0105] On the other hand, even if event lx determination unit 6 determines that event 1B has not occurred in step STIOe, the event lx determination unit 6 proceeds to step ST1 le based on the FBI tracking index! / Determine 1B. For example, if the radio link power cell can be deleted and the FBI tracking index of the base station of the monitor cell to be processed is equal to or less than a predetermined threshold, the process moves to step ST12e, and the cell is removed from the radio link. Send “Measurement Report (Event IB)” to be deleted to the network side.

[0106] In addition, after sending "Measurement Report (Event IB)" or when "Measurement Report (Event IB)" is not sent, the event lx determination unit 6 is designated from the network side as described above. During the trigger time (Time To Trigger) (milliseconds), event 1C is determined based on whether or not there is a cell having a received electric field strength that satisfies the event generation condition (step ST13e). At this time, if there is a cell whose received electric field strength satisfies the above condition, a “Measurement Report (Event 1C)” that sets the cell as a wireless link replacement target is transmitted to the network side (step ST15e).

[0107] On the other hand, even if event lx determination unit 6 determines that event 1C has not occurred in step ST13e, the event lx determination unit 6 proceeds to step ST14e and based on the FBI tracking index! /, Event 1C Judgment is made. For example, when there is a cell in which radio links can be replaced based on a predetermined number of radio links and the FBI tracking index is equal to or less than a predetermined threshold, the process proceeds to step ST15e, where the FBI tracking index is set in advance. Instead of cells that are less than or equal to the set threshold, a measurement report (Event 1C), which is a result of a neighbor search for a cell whose received electric field strength does not satisfy the above conditions, is the target of network replacement. Send.

[0108] The processing from step ST2e to step ST15e described above is performed until the DCH is closed (step ST16e). Communication ends when DCH is closed. In this way, even if event 1B and event 1C do not occur in event determination based on the received electric field strength, if the FBI tracking index is below the threshold, it is determined that the base station does not follow the FBI command. Event 1B and event 1C are generated by making the radio link power deletion target.

[0109] As described above, according to the sixth embodiment, the mobile communication terminal 1 transmits to the base station. Since the uplink signal reception status of the base station is estimated based on the follow-up to the FBI, the monitor cell of the base station that is considered to have poor follow-up and poor reception quality can be deleted from the radio link. Can be improved.

[0110] Embodiment 7.

In the seventh embodiment, a base station having a large uplink transmission power required for a mobile communication terminal by a base station power uplink transmission power control command is a deletion target from a radio link. In this way, by deleting the RL of the base station with a large uplink transmission power required by the uplink transmission power control command, it is possible to release extra radio resources between the mobile communication terminal and the base station. It becomes.

[0111] The basic configuration of the mobile communication terminal according to the seventh embodiment is the same as that shown in Fig. 1 of the first embodiment. The force event lx determination unit 6 and the uplink transmission power command determination unit 1 3 Depending on the uplink transmission power control command transmitted from the base station, an event in which the cell is subject to deletion of the radio link power is determined according to the magnitude of transmission power requested of the terminal 1. For simplification of explanation, FIG. 1 shows all the specific configurations in the present invention. However, the seventh embodiment has the above uplink transmission power for a conventional mobile communication terminal. A configuration in which only the command determination unit 13 and the event lx determination unit 6 are added may be used.

[0112] FIG. 11 is a flowchart showing an operation up to the end of DCH open power communication (end call) of the mobile communication terminal according to Embodiment 7 of the present invention. Hereinafter, the operation will be described using FIGS. 1 and 11 as appropriate.

When the DCH opens and transitions to the communication state (step STlf), the uplink transmission power command determination unit 13 sets the number of base stations currently linked to radio to n, and sets i = l to n to each base station. Then, the own terminal 1 determines an event for deleting the cell from the radio link according to the magnitude of the transmission power requested by the uplink transmission power control command.

[0113] Here, the uplink transmission power command determination unit 13 performs the uplink transmission power control received from the base station BTS (l) for the communicating base station BTS (1) corresponding to i = l (step ST2f). It is determined whether the command requests an increase in uplink signal transmission power or a request for a decrease (step ST3f). At this time, if the transmission power of the uplink signal is requested to be reduced, the base The uplink transmission power control command cumulative value (transmission power requested by the uplink transmission power control command) for the station BTS (l) is decreased (step ST4f).

[0114] In addition, when an increase in uplink signal transmission power is requested, the uplink transmission power control command cumulative value (transmission power requested by the uplink transmission power control command) for base station BTS (l) is increased. (Step ST5f)

[0115] After increasing or decreasing the uplink transmission power control command cumulative value, the uplink transmission power command determination unit 13 determines whether or not the parameter i is the number of radio links n (step ST6f), and reaches n. If not, add i (step ST7f) and repeat the process from step ST3f. The uplink transmission power control command accumulated value is output from the uplink transmission power command determination unit 13 to the event lx determination unit 6.

Thus, in Embodiment 7, the uplink transmission power control command for each radio-linked base station BTS (i) (i = l to n) requests an increase in the transmission power of the uplink signal. Whether or not it is requested to be down is determined by a plurality of frame periods (for example, decoding period), and the accumulated value is adjusted according to the request of the uplink transmission power control command.

[0117] When the parameter i reaches the number of radio links n, the reception field strength measurement unit 12 measures the reception field strength of the downlink signal that also received the monitor cell power via the antenna 2 and the demodulation unit 14, and determines the event lx Output to part 6 (step ST8f). Event lx determination unit 6 determines event 1 A based on the received electric field strength (step ST9f). At this time, if the received electric field strength of the processing target motor cell is equal to or higher than the received electric field strength to be reported, “Measurement Report (Event 1A)” that makes the cell the target of addition of the radio link is sent to the network side. Send (step STIOf).

[0118] After sending “Measurement Report (Event 1 A)” or when “Measurement Report (Event 1 A)” is sent, the event lx judgment unit 6 sets the trigger time (Time For To Trigger) (milliseconds), event 1B is determined based on whether or not there is a cell having a reception field strength that satisfies the event generation condition (step ST1 If). At this time, if there is a cell whose received electric field strength satisfies the above condition, a “Measurement Report (Event IB)” for which the cell is the target of radio link force deletion is transmitted to the network side (step ST13f). [0119] On the other hand, even if event lx determination unit 6 determines that event 1B has not occurred in step ST1 If, the event lx determination unit 6 proceeds to the processing of step ST12f and performs an uplink transmission power control command for the base station of the cell. Event 1B is judged based on the accumulated value. For example, if the radio linkr can also delete a cell, and the uplink transmission power control command cumulative value of the base station of the monitor cell to be processed is equal to or greater than a predetermined threshold, the process proceeds to step ST13f, and the cell “Measurement Report (Event IB)” to be deleted from the wireless link is transmitted to the network side.

[0120] In addition, after sending "Measurement Report (Event IB)" or when "Measurement Report (Event IB)" is not sent, the event lx determination unit 6 is designated from the network side as described above. During the trigger time (Time To Trigger) (milliseconds), event 1C is determined based on whether or not there is a cell having a received electric field strength that satisfies the event generation condition (step ST13e). At this time, if there is a cell whose received electric field strength satisfies the above condition, a “Measurement Report (Event 1C)”, which is a result of a peripheral cell search for the cell as a target for wireless link replacement, is transmitted to the network side (step ST16f).

[0121] On the other hand, even if event lx determination unit 6 determines in step ST14f that event 1C has not occurred, event lx determination unit 6 proceeds to the processing in step ST15f and accumulates the transmission power control command for the base station of the cell. Determine event 1C based on the value. For example, if there is a cell in which radio link replacement is possible based on a predetermined number of radio links and the uplink transmission power control command cumulative value is equal to or greater than a predetermined threshold, step ST1

Transition to 6f, and instead of cells whose uplink transmission power control command accumulated value is greater than or equal to a predetermined threshold value, neighboring cell search for cells whose received electric field strength does not satisfy the above conditions is to be replaced with a radio link The result “Measurement Report (Event 1C)” is sent to the network side.

[0122] The processing from step ST2f to step ST16f described above is performed until the DCH is closed (step ST17f). Communication ends when DCH is closed. Thus, in Embodiment 7, the uplink transmission power control command for each base station is accumulated in a plurality of frame periods (for example, decoding period), and event 1B and event 1C are generated by event determination based on the received electric field strength. However, in some cases, the accumulated value of the uplink transmission power control command (uplink signal) Event IB and event 1C are generated by making the base station with a large number of power demands (No. 2) to be deleted.

[0123] As described above, according to the seventh embodiment, since the radio link of the base station having a large uplink transmission power requested by the uplink transmission power control command is deleted, the mobile communication terminal 1 and the base station are deleted. Extra radio resources with the station can be released.

[0124] Embodiment 8.

In the eighth embodiment, a base station with a small frequency deviation is set as a radio link addition target, and a base station with a large frequency deviation is set as a radio link deletion target. In this way, it is possible to improve communication quality by determining events taking into account frequency deviations in addition to measuring received field strength, and adding and deleting radio links.

[0125] The basic configuration of the mobile communication terminal according to the eighth embodiment is the same as that shown in Fig. 1 of the first embodiment described above, by the force event lx determination unit 6 and the frequency deviation measurement unit 10. Thus, the difference is that an event is determined in which a base station with a small frequency deviation is an addition target of a radio link and a base station with a large frequency deviation is a deletion target of a radio link. For simplicity of explanation, FIG. 1 shows all the unique configurations in the present invention, but this Embodiment 8 performs event determination as described above for a conventional mobile communication terminal. The event lx determination unit 6 and the frequency deviation measurement unit 10 may be added.

FIG. 12 is a flowchart showing the operation up to the end of DCH open power communication (end call) of the mobile communication terminal according to Embodiment 8 of the present invention. Hereinafter, the operation will be described using FIGS. 1 and 12 as appropriate.

When the DCH opens and transitions to the communication state (step S Tig), the frequency deviation measurement unit 10 measures the frequency deviation at the antenna 2 end of the terminal 1 including the influence of AFC etc. on the downstream signal of the monitor cell power. Then, the event is output to the event lx determination unit 6 (step ST2g). The frequency f that the demodulator 14 of the mobile communication terminal 1 is waiting for is the temperature deviation of the temperature compensated crystal oscillator (TcXo) or the AFC (Automatic Frequency Control) relative to the absolute frequency fO of the carrier. The pull-in error is included. Therefore, if the frequency of the downlink signal from the base station is ff, the frequency deviation due to the temperature deviation and AFC pull-in error can be expressed as (ff f). [0127] Next, the received electric field strength measuring unit 12 measures the received electric field strength of the downlink signal that is also received by the monitor cell via the antenna 2 and the demodulator 14 (step ST3g), and outputs it to the event lx determination unit 6 To do. Event lx determination unit 6 determines event 1 A based on the received electric field strength (step ST4g). At this time, if the received electric field strength of the processing target monitor cell is equal to or higher than the received electric field strength to be reported, the “Measurement Report (Event 1A)” that is the result of the peripheral cell search for adding the cell to the radio link. "To the network side (step ST6g).

[0128] On the other hand, even if event lx determination unit 6 determines that event 1A has not occurred in step ST4g, event lx determination unit 6 proceeds to the processing in step ST5g and sets the frequency deviation in the downlink signal from the base station of the cell. Based on the event 1 A determination. For example, if it is possible to add to the radio link and the frequency deviation of the base station BTS of the monitoring cell to be added is less than the predetermined additional frequency deviation threshold, the process moves to step ST6g and the cell is added to the radio link. Send the target “Measurement Report (Event 1A)” to the network side.

[0129] In addition, the event lx determination unit 6 does not transmit the "Measurement Report (Event 1 A)" or if there is no "Measurement Report (Event 1 8)" transmission, the trigger time specified from the network side ( During Time To Trigger) (milliseconds), event 1B is determined based on whether or not there is a cell having a received electric field strength that satisfies the event generation condition (step ST7g). At this time, if there is a cell whose received electric field strength satisfies the above conditions, a `` Measurement Report (Event IB) '' that is a result of searching for neighboring cells whose radio link power is to be deleted is transmitted to the network side (step ST9g).

[0130] On the other hand, even if event lx determination unit 6 determines that event 1B has not occurred in step ST7g, event lx determination unit 6 proceeds to the processing in step ST8g and adds the frequency deviation in the downlink signal from the base station of the cell. Based on this, the event 1B is judged. For example, if the radio link power can also delete a cell, and the frequency deviation in the downlink signal of the base station power of the processing target monitor cell is equal to or greater than a predetermined deletion target frequency deviation threshold, the process proceeds to step ST 9g. Then, a “Measurement Report (Event IB)” for deleting the cell from the radio link is transmitted to the network side. [0131] In addition, after sending "Measurement Report (Event IB)" or when "Measurement Report (Event IB)" is not sent, the event lx determination unit 6 is designated from the network side as described above. During the trigger time (Time To Trigger) (milliseconds), event 1C is determined based on whether or not there is a cell having a received electric field strength that satisfies the event generation condition (step ST10g). At this time, if there is a cell whose received electric field strength satisfies the above condition, a “Measurement Report (Event 1C)”, which is a result of a peripheral cell search for the cell as a target for wireless link replacement, is transmitted to the network side (step ST12g).

[0132] On the other hand, even if event lx determination unit 6 determines that event 1C has not occurred in step STIOg, the event lx determination unit 6 proceeds to the processing in step ST1 lg and performs frequency deviation in the downlink signal from the base station of the cell. Determine event 1C based on For example, a base station whose frequency deviation in the downlink signal from the cell is less than a predetermined replacement additional frequency deviation threshold value and whose frequency deviation is larger than a predetermined replacement deletion frequency deviation threshold value in a base station linked to a radio link. If there is a station, the process proceeds to step ST12g, and instead of the cell to be deleted, a “Measurement Report (Event 1C)” for replacing the replacement target cell with the radio link is transmitted to the network side.

[0133] The processing from step ST2g to step ST12g described above is performed until the DCH is closed (step ST13g). Communication ends when DCH is closed. Thus, even when event 1B does not occur, if the frequency deviation between the deleted base station and mobile communication terminal 1 is equal to or greater than the deleted frequency deviation threshold, event 1B reporting is performed. Similarly, even when event 1C does not occur, the frequency deviation between the additional base station and mobile communication terminal 1 is interchanged and is below the additional frequency deviation threshold, and the deleted base station and mobile communication terminal 1 If the frequency deviation is greater than or equal to the replacement deletion frequency deviation threshold, report event 1C.

As described above, according to the eighth embodiment, in addition to the measurement of the received electric field strength, the event determination taking into account the frequency deviation is performed and the addition and deletion of the monitor cell are performed. It becomes possible to improve.

[0135] Note that the concept in Embodiment 8 can also be applied to the determination of celery selection in the FACH state. In other words, the cell reselection determination unit 8 Cell reselection is determined according to the frequency deviation in the downlink signal from the base station. This is expected to improve the transmission rate.

[0136] Embodiment 9.

In the ninth embodiment, a base station with a small Doppler shift is set as a radio link addition target, and a base station with a large Doppler shift is set as a radio link deletion target. The Doppler shift observed by the mobile communication terminal with the downlink received signal is equally applied to the uplink signal received at the base station. For this reason, as in the ninth embodiment, the base station cell with a small Doppler shift is set as the addition target of the radio link, and the base station cell with a large Doppler shift is set as the deletion target of the radio link. It is possible to select a base station with good reception quality.

[0137] The Doppler shift can be expressed as (ff-fO) where fO is the absolute frequency of the carrier and ff is the frequency of the downlink signal from the base station. Note that the Doppler shift is measured using the downlink received signal for each base station.

[0138] The basic configuration of the mobile communication terminal according to the ninth embodiment is the same as that shown in Fig. 1 of the first embodiment described above by the force event lx determination unit 6 and the Doppler shift measurement unit 11. The difference is that an event is determined in which a base station with a small Doppler shift amount is an addition target of a radio link and a base station with a large Doppler shift amount is a deletion target of a radio link. For simplicity of explanation, FIG. 1 shows all the unique configurations in the present invention. However, in the ninth embodiment, event determination as described above is performed on a conventional mobile communication terminal. An event lx determination unit 6 and a Doppler shift measurement unit 11 may be added.

FIG. 13 is a flowchart showing the operation up to the end of DCH open power communication of the mobile communication terminal according to Embodiment 9 of the present invention. In the following, the operation will be described using FIG. 1 and FIG. 13 as appropriate. When the DCH opens (step STlh) and shifts to the communication state, the Doppler shift measurement unit 11 measures the Doppler shift for the downlink signal from each base station (step ST2h) and outputs it to the event lx determination unit 6. .

[0140] Next, the received electric field strength measuring unit 12 measures the received electric field strength of the downlink signal received by the monitor cell via the antenna 2 and the demodulating unit 14, and outputs the received signal strength to the event lx determining unit 6 ( Step ST3h). Event lx determination unit 6 determines event 1A based on the received electric field strength (step ST4h). At this time, if the received electric field strength of the monitor cell to be processed is equal to or higher than the received electric field strength to be reported, “Measurement Report (Event 1A)”, which is the result of the peripheral cell search for adding the cell to the radio link. Is sent to the network side (step ST6h).

[0141] On the other hand, even if event lx determination unit 6 determines that event 1 A has not occurred in step ST4h, the event lx determination unit 6 proceeds to the processing of step ST5h and performs an event based on the Doppler shift in the base station of the cell. Perform 1A determination. For example, if a cell can be added to the radio link, and if the Doppler shift of the base station BTS of the target monitor cell to be added is less than a predetermined additional Doppler shift threshold, the process proceeds to Step ST6h. Send “Measurement Report (Event 1A)” to the network side, where the cell is the target of the wireless link addition.

[0142] In addition, the event lx determination unit 6 does not transmit the “Measurement Report (Event 1 A)” or if there is no “M easurement Report (Event 1 8)” transmission, the trigger time specified from the network side ( During Time To Trigger) (milliseconds), event 1B is determined based on whether or not there is a cell having a received electric field strength that satisfies the event generation condition (step ST7h). At this time, if there is a cell whose received electric field strength satisfies the above condition, a “Measurement Report (Event IB)” for which the cell is a target for deleting the radio link strength is transmitted to the network side (step ST9h).

[0143] On the other hand, even if event lx determination unit 6 determines that event 1B has not occurred in step ST7h, event lx determination unit 6 proceeds to the processing of step ST8h and determines event 1B based on the Doppler shift of base station BTS of the cell. Judgment of For example, if the cell can be deleted from the radio link and the Doppler shift of the base station BTS of the monitoring cell to be processed is larger than the predetermined deletion Doppler shift threshold, the process moves to step ST9h and the cell is wirelessly transmitted. Send “Measurement Report (Event IB)” to be deleted from the link to the network side.

[0144] In addition, after transmitting "Measurement Report (Event IB)" or when "Measurement Report (Event IB)" has not been transmitted, the event lx determination unit 6 performs the same as above. Between designated from the side the trigger time (Time the To Trigger) (ms), determines an event 1C depending force whether there is a cell of a received field strength which satisfies the generation condition of an event (step S T10h) _o At this time, If there is a cell whose received electric field strength satisfies the above conditions, a “Measurement Report (Event 1C)” is sent to the network side with the cell as a target for wireless link replacement (step ST12h).

[0145] On the other hand, even if event lx determination unit 6 determines that event 1C has not occurred V in step STIOh, the event lx determination unit 6 proceeds to the process in step ST1 lh and is based on the Doppler shift of the base station BTS of the cell. To determine Event 1C. For example, the Doppler shift of the base station BTS of the cell is less than a predetermined replacement addition Doppler shift threshold, and larger than the predetermined replacement deletion Doppler shift threshold in the base station linked to the radio link If there is another base station, move to step ST12h, and instead of the cell to be deleted, send the “Measurement Report (Event 1C)” that is the result of the neighboring cell search to replace the cell to be replaced and replaced with the radio link to the network side. Send.

[0146] The above-described processing from step ST2h to step ST12h is performed until DCH is closed (step ST13h). Communication ends when DCH is closed. Thus, even when event 1B does not occur, event 1B is reported if the Doppler shift between the base station to be deleted and mobile communication terminal 1 is greater than or equal to the deletion Doppler shift threshold. Similarly, even if event 1C does not occur, the Doppler shift between the base station to be added and mobile communication terminal 1 is switched below the additional Doppler shift threshold, and the base station to be deleted and the mobile If communication terminal 1's Doppler shift is greater than or equal to the replacement deletion Doppler shift threshold, report event 1C.

[0147] As described above, according to the ninth embodiment, in addition to the measurement of the received electric field strength, the monitor cell is added to and deleted from the radio link by event determination using the Doppler shift amount. Can be improved.

[0148] Note that the concept in the ninth embodiment can also be applied to the determination of celery selection in the FACH state. That is, the celery selection determination unit 8 determines celery selection according to the Doppler shift between the base station of the monitor cell and the terminal 1 itself. As a result, the transmission rate is expected to improve. [0149] In the configuration of Fig. 1, the event lx determination unit 6 performs the instantaneous value of the received electric field strength immediately after the DCH is opened, as described in the first embodiment, the third embodiment to the ninth embodiment. , Receive field strength variation over time, Tracking capability for downlink transmission power control command, Tracking capability for uplink transmission power control command, Tracking capability for FBI, Frequency deviation, Doppler shift amount Judgment may be made. Similarly, the celery selection determination unit 8 may perform the celery selection determination according to a combination of any of the instantaneous value of received electric field strength, frequency deviation, and Doppler shift amount immediately after the FACH is opened.

Industrial applicability

[0150] As described above, the mobile communication terminal according to the present invention can perform cell reselection and not-over at an appropriate timing even when moving at high speed. Suitable for devices!

Claims

The scope of the claims

[1] In a mobile communication terminal having one or more connectable cells as a communication partner cell among a plurality of cells served by a plurality of base stations,

A reception level measurement unit for measuring the reception level of the cell;

An event determination unit that determines addition, deletion, or replacement of the cell to the radio link based on the reception level measured by the reception level measurement unit;

When the event determination unit starts communication, based on the instantaneous value of the reception level at the time of opening a channel for controlling communication between the base station and the terminal, the event determination unit A mobile 1§ terminal characterized by determining addition, deletion or replacement.

[2] In a mobile communication terminal having one or more connectable cells as a communication partner cell among a plurality of cells served by a plurality of base stations,

A cell reselection determination unit that determines reselection of a standby cell to be called based on the reception level measured by the reception level measurement unit;

The cell reselection determination unit determines re-selection of a standby cell to call based on an instantaneous value of the reception level at the time of channel establishment for starting a transmission sequence when starting transmission. A mobile communication terminal.

[3] In a mobile communication terminal having one or more connectable cells as a communication partner cell among a plurality of cells served by a plurality of base stations,

A time variation measuring unit for measuring a time variation of the reception level measured by the reception level measuring unit;

An event determination unit for determining addition, deletion or replacement of the cell to the radio link based on the reception level;

The time change amount measuring unit measures a time change amount of a reception level for a cell in communication measured by the reception level measurement unit or another cell whose reception level is monitored during communication, In addition to the reception level, the event determination unit adds the cell to the radio link based on a time change amount of the reception level of the cell in communication or another cell whose reception level is monitored during communication. A mobile communication terminal characterized by determining deletion or replacement.

[4] In a mobile communication terminal having one or more connectable cells as a communication partner cell among a plurality of cells served by a plurality of base stations,

A speed measuring unit for measuring a speed of approaching or leaving the base station as the terminal moves,

The event determination unit determines addition, deletion, or replacement of the cell to a radio link based on the speed measured by the speed measurement unit in addition to the reception level. .

[5] In a mobile communication terminal having one or more connectable cells as a communication partner cell among a plurality of cells served by a plurality of base stations,

The event determination unit, based on the degree of followability of the downlink signal to the control command for controlling the transmission power of the downlink signal transmitted from the terminal to the base station, in addition to the reception level, A mobile communication terminal characterized by determining deletion or replacement of link force.

[6] In a mobile communication terminal having one or more connectable cells as a communication partner cell among a plurality of cells served by a plurality of base stations,

An event determination unit for determining addition, deletion or replacement of the cell to the radio link based on the reception level; The event determining unit, based on the degree of followability to the control information for controlling the phase angle of the downlink signal transmitted from the own terminal to the base station, in addition to the reception level, A mobile communication terminal characterized by determining deletion or replacement.

[7] In a mobile communication terminal having one or more connectable cells as a communication destination cell among a plurality of cells served by a plurality of base stations,

A command determination unit for determining a base station having a large uplink transmission power required by a control command for controlling transmission power of an uplink signal transmitted from the base station to the terminal; and the cell based on the reception level. An event determination unit that determines whether to add, delete, or replace

The event determining unit determines deletion or replacement of the cell from the radio link based on the magnitude of transmission power requested by the control command determined by the command determining unit in addition to the reception level. A mobile communication terminal characterized by that.

[8] In a mobile communication terminal having one or more connectable cells as a communication destination cell among a plurality of cells served by a plurality of base stations,

A frequency deviation measurement unit that measures a frequency deviation of a downlink signal from the base station, and an event determination unit that determines addition, deletion, or replacement of the cell to the radio link based on the reception level,

The event determination unit determines addition, deletion, or replacement of the cell to the radio link based on the frequency deviation measured by the frequency deviation measurement unit in addition to the reception level. Body communication terminal.

[9] In a mobile communication terminal having one or more connectable cells as a communication partner cell among a plurality of cells served by a plurality of base stations,

A frequency deviation measuring unit for measuring a frequency deviation of a downlink signal from the base station, and a waiting to be called based on the reception level measured by the reception level measuring unit. A cell reselection determination unit that determines reselection of a receiving cell;

The cell reselection determination unit determines re-selection of a standby cell to be called according to a frequency deviation value measured by the frequency deviation measurement unit in addition to the reception level. Terminal.

[10] In a mobile communication terminal having at least one connectable cell as a communication destination cell among a plurality of cells served by a plurality of base stations,

A Doppler shift measurement unit that measures a Doppler shift of a downlink signal of the base station power, and an event determination unit that determines addition, deletion, or replacement of the cell to the radio link based on the reception level,

The event determining unit determines addition, deletion, or replacement of the cell to the radio link according to a Doppler shift amount measured by the Doppler shift measurement unit in addition to the reception level. Communication terminal.

[11] In a mobile communication terminal having at least one connectable cell as a communication destination cell among a plurality of cells served by a plurality of base stations,

A Doppler shift measurement unit that measures a Doppler shift of a downlink signal of the base station power, and a cellli that determines reselection of a standby cell to be called based on the reception level measured by the reception level measurement unit. A selection determination unit,

The cell reselection determination unit determines re-selection of a standby cell to be called according to a Doppler shift amount measured by the Doppler shift measurement unit in addition to the reception level. Terminal.