JP2001267962A - Mobile wireless terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mobile wireless terminal that can prevent a load required for reassignment processing of a reception path from being increased even when a reception path reassignment period is decreased to enhance a reception characteristic. SOLUTION: A control section 18a monitors a reception level on the basis of demodulation results of fingers 13, 14, 15. When the control section 18a detects a finger whose reception path requires revision because the reception level is lower than a preset threshold value Pth, a path assignment section 17a selects a path optimum to the reception among path objects having been detected by a path search section 16 and assigns new path timing only to the finger whose reception path requires revision.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Spread Spectrum-Direct Seq.
Rake that employs multiple receivers
The present invention relates to a mobile radio terminal used in a mobile radio communication system such as a mobile phone system or a mobile phone system that performs reception.

[0002]

2. Description of the Related Art As is well known, a mobile radio terminal used in a radio communication system adopting a direct spread spectrum spreading method is provided with a plurality of fingers for despreading a received signal and extracting symbols. The radio signals (paths) passing through different paths are received, and the symbols extracted by the plurality of fingers are RAKE-combined to improve the anti-fading characteristics.

Conventionally, as a method of allocating a path to be received by each finger, a matched filter can perform reception by performing a spreading process of multiplying a received signal by a spread code at various timings at a predetermined cycle. There is a first path allocation method of detecting paths and allocating a path having a higher received power to fingers.

Further, as a second path assignment method,
There is a method of accumulating reception power of a path obtained by a matched filter for each path for a predetermined time, determining a path suitable for reception based on the accumulated reception power, and allocating a path to a finger. .

However, in the first path assignment method, if the reassignment cycle of the reception path is lengthened, it becomes impossible to follow a rapid change in the path due to the influence of buildings moving in a high speed or an urban area, and the reception characteristics deteriorate. There is a problem,
On the other hand, when the re-allocation cycle of the reception path is shortened to improve the reception characteristics, there is a problem that the load required for the re-allocation processing increases.

In the second path assignment method, if the accumulated time of the matched filter output is lengthened to improve the selection accuracy of the optimum path, a sudden change occurs in the path due to shadowing or the like. There is a problem that the reception characteristics are deteriorated.On the other hand, if the accumulated time of the matched filter output is set short to improve the reception characteristics, not only the accuracy of selecting the optimum path is deteriorated, but also the reception power of the path is relatively slow. However, there is a problem that the reception characteristic is deteriorated when the frequency is varied.

[0007]

In the conventional mobile radio terminal, if the reassignment period of the reception path is lengthened, it becomes impossible to follow a rapid change in the path due to the influence of a building moving in a high speed or an urban area, and the reception characteristic becomes poor. There is a problem of deterioration,
On the other hand, when the re-allocation cycle of the reception path is shortened to improve the reception characteristics, there is a problem that the load required for the re-allocation processing increases.

Further, in the conventional mobile radio terminal, if the accumulated time of the matched filter output is lengthened to improve the selection accuracy of the optimum path, a sudden change occurs in the path due to the influence of shadowing or the like, so that the reception is not possible. If the accumulation time of the matched filter output is set short to improve the reception characteristics, the selection accuracy of the optimal path is not only deteriorated, but also the reception power of the path fluctuates relatively slowly. In such a case, the reception characteristics are deteriorated, so that it is difficult to cope with a change in the reception environment, and there is a problem that it is not possible to maintain good reception characteristics.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problem, and prevents the load required for the reassignment process from increasing even if the reassignment period of the reception path is shortened to improve reception characteristics. It is an object of the present invention to provide a mobile radio terminal capable of performing the operation.

Another object of the present invention is to provide a mobile radio terminal capable of maintaining a good reception characteristic in response to a change in the reception environment. In addition, the present invention
It is an object of the present invention to provide a mobile radio terminal that can support various reception environments and maintain good reception characteristics.

[0011]

In order to achieve the above object, the present invention according to claim 1 employs a direct spread spectrum spread method and a mobile radio terminal that performs rake reception using a plurality of receivers. A path detection means for performing a despreading process of multiplying a reception signal frequency-converted into a baseband signal by a spread code at various timings to detect a path suitable for reception, and demodulated by a plurality of receivers. Power level detecting means for detecting the received power level of the received signal for each receiver, and monitoring the detection result of the power level detecting means. When the received power level falls below a preset threshold value, A path allocating unit that allocates a new path detected by the path detecting unit to a receiver that demodulates a signal of a power level is provided.

In the mobile radio terminal having the above configuration, the received power level is monitored from the demodulation result, a finger whose reception path needs to be changed is detected, and a new path timing is assigned only to the detected finger. I have. That is, for the finger for which the normal reception is performed, the path timing is not updated unnecessarily.

Therefore, according to the mobile radio terminal having the above configuration, even if the re-allocation cycle of the reception path is shortened in order to improve the reception characteristics, it is possible to prevent the load required for the re-allocation process from increasing.

According to a second aspect of the present invention, there is provided a mobile radio terminal that employs a direct spread spectrum spreading method and performs Rake reception using a plurality of receivers. By performing despreading processing of multiplying a spreading code at various timings, a path detecting means for detecting a path suitable for reception, and a reception power level of a signal demodulated by a plurality of receivers, for each receiver. A power level detecting means for detecting, and a detection result of the power level detecting means at an update cycle preset for each of a plurality of receivers, and for a receiver whose received power level falls below a preset threshold value, And a path allocating means for allocating a new path detected by the path detecting means.

[0015] In the mobile radio terminal having the above configuration, the path update cycle is set for each receiver, and the reception path is updated. Therefore, according to the mobile radio terminal having the above configuration, the finger whose update cycle is set to be long enables selection of an optimal path in an environment where the path or the reception power fluctuates relatively slowly and the finger whose update cycle is set to be short. Therefore, the optimum path can be selected even in an environment where the path or the reception power fluctuates rapidly, so that good reception characteristics can be maintained in various reception environments.

Further, according to the present invention, in a mobile radio terminal that employs a direct spread spectrum spreading method and performs Rake reception using a plurality of receivers, a reception signal that has been frequency-converted into a baseband signal is converted to a baseband signal. Despreading means for performing despreading processing of multiplying a spreading code at various timings to detect signal strength of a receivable path and despreading timing, and for each receivable path detected by the despreading means. Path detection means for accumulating the signal strength at a predetermined accumulation period, and detecting a path suitable for reception from the accumulation result;
The received power level of the signal demodulated by a plurality of receivers,
Power level detecting means for each receiver, and cumulative cycle variable means for monitoring the detection result of the power level detecting means and varying the cumulative cycle in the path detecting means in accordance with the fluctuation of the received power level. To be configured.

In the mobile radio terminal having the above-described configuration, the accumulated time of the received power level, which is used as a criterion for the path detection in the path detecting means, is changed according to the fluctuation of the received power level. Therefore, according to the mobile radio terminal having the above-described configuration, it is possible to cope with a change in the reception environment that appears due to a change in the reception power level and maintain good reception characteristics.

Furthermore, the present invention according to claim 9 provides:
In a mobile radio terminal that adopts a direct spread spectrum spreading method and performs Rake reception using a plurality of receivers, a despreading process of multiplying a received signal frequency-converted into a baseband signal by a spreading code at various timings is performed. Despreading means for detecting the signal strength of the receivable path and the timing of despreading, and for each receivable path detected by the despreading means, accumulates the signal strength at a predetermined accumulation cycle,
Path detection means for detecting a path suitable for reception from the accumulated result, reception power levels of signals demodulated by a plurality of receivers, power level detection means for detecting for each receiver,
The detection result of the power level detecting means is monitored, and a new path detected by the path detecting means is assigned to a receiver whose received power level is lower than a preset threshold, and a new path is assigned to the receiver. Path allocation means for receiving
A moving speed detecting means for detecting a moving speed of the mobile radio terminal, a cumulative cycle variable means for monitoring a detection result of the moving speed detecting means, and changing a cumulative cycle in the path detecting means in accordance with a change in the moving speed; Is provided.

In the mobile radio terminal having the above-described configuration, the accumulated time of the received power level, which is used as a criterion for the path detection in the path detection means, is varied according to the moving speed of the mobile radio terminal. Therefore, according to the mobile radio terminal configured as described above, it is possible to maintain a good reception characteristic in response to a change in the reception environment that appears in a change in the moving speed.

According to the twelfth aspect of the present invention, there is provided a mobile radio terminal which adopts a direct spread spectrum spread system and performs Rake reception using a plurality of receivers, the reception signal being frequency-converted into a baseband signal. Despreading means for performing a despreading process of multiplying the spread code at various timings to detect a signal strength of a receivable path and despreading timing, and for each receivable path detected by the despreading means. A path detection unit that accumulates the signal strength at a predetermined accumulation period, and detects a path suitable for reception from the accumulation result, and detects a base station to which the mobile radio terminal is connected at a predetermined period. A base station detecting means for monitoring a detection result of the base station detecting means, and changing a cumulative cycle in the path detecting means in accordance with a change in identification information of a connected base station; And to constitute by comprising a variable means.

In the mobile radio terminal having the above configuration, the accumulated time of the received power level, which is used as a criterion for path detection in the path detection means, is made variable in accordance with a change in the base station to which the mobile radio terminal is connected. ing. Therefore, according to the mobile radio terminal having the above configuration, it is possible to cope with a change in the reception environment caused by a change in the connected base station and maintain good reception characteristics.

According to a fifteenth aspect of the present invention, in a mobile radio terminal that employs a direct spread spectrum spreading method and performs Rake reception using a plurality of receivers, a reception signal frequency-converted into a baseband signal is converted to a baseband signal. Despreading means for performing a despreading process of multiplying a spreading code at various timings to detect a signal strength of a receivable path and despreading timing, and a signal of a receivable path detected by the despreading means. Path detection means for accumulating the strength at a plurality of different accumulation periods and detecting a path suitable for reception from the accumulation result, and path assignment for allocating a new path detected by the path detection means at a preset assignment cycle And means.

In the mobile radio terminal having the above configuration, the reception power level, which is used as a determination material for path detection in the path detection means, is accumulated at a plurality of different accumulation periods, and a path suitable for reception is determined based on the accumulation result. And assign it to the receiver.

Therefore, according to the mobile radio terminal having the above configuration, the path and the reception power can be relatively slowly controlled by the receiver to which the optimum path detected based on the reception power level accumulated in the long accumulation period is allocated. Optimal path can be received in a fluctuating environment, and the optimal path is detected based on the received power level accumulated in a short accumulation period. Since good paths can be received, good reception characteristics can be maintained in various reception environments.

[0025]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a first embodiment of the present invention.
3 shows a configuration of a receiving system of the mobile wireless terminal device according to the embodiment.

The A / D converter 11 performs A / D conversion and sampling of the reception signal received through the antenna 10, and converts the reception baseband signal obtained by the A / D conversion into 12 matched filters and 13, 14, 15 Output to each finger.

The matched filter 12 detects all receivable paths from the spread signal in the received baseband signal, measures the power of each detected path, and performs a path search on the detected / measured result. Output to the unit 16.

The path search section 16 includes the matched filter 1
Among the paths detected in step 2, the path having the higher received power is set as a candidate path, and a phase in a path slot (hereinafter, referred to as path timing) indicating the despread timing of the candidate path is notified to the path allocating unit 17a.

The path allocating unit 17a includes a control unit 18 described later.
a, the path candidates corresponding to the path timings specified by the control unit 18a are excluded from the path candidates, and the path timings corresponding to the remaining path candidates are set to the finger 1 specified by the control unit 18a.
Assign to 3-15.

The fingers 13 to 15 are connected to a path allocating unit 17a.
At the assigned path timing, the received baseband signal is despread and demodulated.
The signal is output to an AKE combining unit (not shown) and the control unit 18a. Each of the fingers 13 to 15 notifies the control unit 18a of path timing identification information used for despreading.

The control unit 18a forms the center of the control of the allocation of the paths to be received by the fingers 13 to 15, and includes a reception power memory 181a and a path timing memory 182a, based on information stored in these memories. Then, it instructs the path allocating unit 17a to allocate a reception path.

The control unit 18a controls each finger 13
The received power is detected from the demodulation results of the fingers 13 to 15, and the received power of the demodulation results of the fingers 13 to 15 is recorded in the reception power memory 181a in association with the identification information of the fingers 13 to 15.

On the other hand, the path timing memory 182a stores identification information of the path timing assigned to each of the fingers 13 to 15 in association with the identification information of each of the fingers 13 to 15.

Next, the operation of controlling the allocation of the reception paths to the fingers 13 to 15 of the mobile radio terminal having the above configuration will be described. FIG. 2 is a flowchart showing the control operation, which is a process performed by the control unit 18a.

In the following description, the finger 13 is referred to as a finger 1 for simplicity, and the finger 1
4 is referred to as finger 2 and finger 15 is referred to as finger 3.

First, in step 2a, after setting the parameter n to "0", the received powers P1 to P3 of the demodulated results of the fingers 1 to 3 are detected and associated with the identification information of the fingers 1 to 3. The corresponding received powers P1 to P3 are recorded in the received power memory 181a, and the process proceeds to step 2b.

Next, at step 2b, "1" is added to the parameter n, and the routine goes to step 2c. Step 2
In step c, a preset determination threshold value Pth is compared with the received power Pn stored in the received power memory 181a. If the received power Pn is equal to or greater than the determination threshold value Pth, the process proceeds to step 2d. On the other hand, if the received power Pn is less than the determination threshold Pth, the process proceeds to step 2e.

In step 2d, by referring to the path timing memory 182a, the identification information of the path timing recorded in association with the finger n is read, and this path timing is notified to the path allocating unit 17a, and step 2f is executed.
Move to

On the other hand, the path allocating unit 17a deletes the path corresponding to the path timing notified by the control unit 18a from the candidate paths notified by the path search unit 16 in step 2d.

At step 2e, it is determined whether or not n is "3", that is, whether or not the processing from step 2c to step 2d has been performed for all the fingers 1 to 3. If all the fingers 1 to 3 have been performed, the process proceeds to step 2f. On the other hand, if there is a finger that has not been performed yet, the process proceeds to step 2b.
Move to

In step 2f, the process waits for the arrival of the update period T of the path timing assigned to the fingers 1 to 3. Eventually, when the update cycle T arrives, step 2g
Move to

At step 2g, n is reset to "0", and the routine goes to step 2h. In step 2h, n
Is added to "1", and the routine goes to Step 2i. In step 2i, it is determined whether or not the finger n has been notified of the path timing in step 2d. If the finger n has been notified, step 2
k, on the other hand, if not notified, the process proceeds to step 2j.

In step 2j, the identification information of the finger n is notified to the path allocating unit 17a, and the process proceeds to step 2k. On the other hand, the path allocating unit 17a allocates the path timing corresponding to the path candidate to the finger n.

In step 2k, it is determined whether or not n is "3", that is, in step 2i, all fingers 1
3 are determined. Here, if the processing has been performed for all the fingers 1 to 3, the processing is terminated. On the other hand, if there is a finger that has not been performed, the process proceeds to step 2h.

As described above, in the mobile radio terminal having the above configuration, the control unit 18a monitors the reception level from the demodulation result, detects the finger whose reception path needs to be changed, and only detects the finger that is detected. A new path timing is assigned. In other words, the path timing is not unnecessarily updated for the finger for which the normal reception is performed.

At the time of normal reception, it is not necessary to perform reassignment to all fingers. Therefore, according to the mobile radio terminal having the above configuration, reassignment of the reception path is performed in order to improve reception characteristics. Even if the period is shortened, it is possible to prevent the load required for the reallocation processing from increasing.

Next, a second embodiment of the present invention will be described. FIG. 3 shows a configuration of a mobile wireless terminal device according to the second embodiment of the present invention.

The A / D converter 11 performs A / D conversion and sampling of the received signal received through the antenna 10, and converts the received baseband signal obtained by the A / D conversion into 12 matched filters and 13, 14, and 15. Output to each finger.

The matched filter 12 detects all receivable paths from the spread signal in the received base band signal, measures the power of each detected path, and searches the detected / measured result for a path search. Output to the unit 16.

The path search section 16 includes the matched filter 1
Among the paths detected in step 2, a path having a high received power is set as a candidate path, and a phase in a path slot (hereinafter, referred to as path timing Ptm) indicating the despread timing of the candidate path is notified to the path allocating unit 17b.

The path allocating unit 17b includes a control unit 18 to be described later.
For the fingers 13 to 15 designated by b, an optimal path is selected from the path candidates, and a path timing Ptm corresponding to the selected path is assigned.

The fingers 13 to 15 include a path allocating unit 17b
At the assigned path timing Ptm, the received baseband signal is despread and demodulated, and the demodulation result is output to a subsequent RAKE combining unit (not shown) and the control unit 18b. Each of the fingers 13 to 15 outputs the identification information of the path timing Ptm used for the despreading to the control unit 18.
Notify b.

The control unit 18b forms the center of the control for allocating paths to be received by the fingers 13 to 15, and includes an allocation period memory 181b and a path timing memory 182.
b, and instructs the path allocating unit 17b to allocate a reception path based on the information stored in these memories.

Then, the control unit 18b records the update period Tn of the path timing for each of the fingers 13 to 15 in the allocation period memory 181b. Note that the allocation cycle memory 1
The minimum update cycle Tmin, the maximum update cycle Tmax, and the variable cycle width Td are recorded in advance in 81b.

Further, the control unit 18b records the identification information Ptm of the path timing currently and in the past assigned in a time sequence in the path timing memory 182b in association with each of the fingers 13 to 15.

Next, the operation of controlling the allocation of the reception paths to the fingers 13 to 15 of the mobile radio terminal having the above configuration will be described. FIG. 4 is a flowchart showing this control operation, which is a process performed by the control unit 18b.

In the following description, for simplicity, the finger 13 is referred to as the finger 1 and the finger 1
4 is referred to as finger 2 and finger 15 is referred to as finger 3.

First, at step 4a, n is reset to "0", and the routine goes to step 4b. In step 4b, “1” is added to n, and the process proceeds to step 4c.

In step 4c, the allocation period memory 181
Referring to b, it is determined whether or not the update cycle Tn of the finger n has arrived. Here, when the update period Tn has arrived, the process proceeds to step 4d, and when the update period Tn has not arrived, the process proceeds to step 4j.

In step 4d, the identification information of the finger n is notified to the path allocating unit 17b, and the process proceeds to step 4e. On the other hand, the path allocating unit 17b determines the path timing Ptm corresponding to the path optimal for reception from the path candidate.
Is assigned to the finger n.

Then, the finger n despreads the received baseband signal with the assigned path timing Ptm, and also performs the assigned path timing Ptm.
Is notified to the control unit 18b.

On the other hand, the control unit 18b records the path timing Ptm notified from the finger n in a register corresponding to the finger n of the path timing memory 182b and storing the currently used path timing. .

In step 4e, by referring to the information recorded in the register corresponding to the finger n of the path timing memory 182b, the identification information of the currently used path timing matches the identification information of the previously allocated path timing. It is determined whether or not to perform. Here, if they match, the process proceeds to step 4f, while if they do not match, the process proceeds to step 4h.

In step 4f, it is determined whether or not the currently used path timing is continuous A times by referring to the information recorded in the register corresponding to the finger n of the path timing memory 182b. Here, if the number of consecutive times is A, the process proceeds to step 4g. If not, the process proceeds to step 4j.

In step 4g, the update period Tn is increased from the current value by the period variable width Td, and the process proceeds to step 4i. If the update cycle Tn is already the maximum update cycle Tmax, it is not increased.

On the other hand, in step 4h, the update cycle Tn is reduced from the current value by the cycle variable width Td, and the process proceeds to step 4i. If the update cycle Tn is already the shortest update cycle Tmin, it is not reduced.

In step 4i, the register corresponding to the finger n of the path timing memory 182b is cleared,
Move to step 4j. In step 4j, it is determined whether or not n is “3”, that is, whether or not the processing after step 4d has been performed for all the fingers 1 to 3. Here, if the processing has been performed for all the fingers 1 to 3, the process is terminated. On the other hand, if there is a finger that has not been performed yet, the process proceeds to step 4b.

As described above, in the mobile radio terminal having the above configuration, a path update cycle is set for each finger, and when the same path is continuously assigned to the same finger, the path update cycle of the finger is changed. When the assigned path fluctuates for each update cycle in the same finger, the path update cycle of the finger is shortened.

Therefore, according to the mobile radio terminal having the above configuration, the path update cycle can be set for each finger, and the path and the received power fluctuate relatively slowly due to the finger whose update cycle is set long. The optimal path can be selected in an environment where there is a problem, and the optimal path can be selected even in an environment where the path and the received power fluctuate rapidly due to the finger whose update cycle is set short, so that good reception characteristics are maintained in various reception environments can do.

Further, for a finger for which normal reception is performed stably, the update period is extended, so that the path timing is not updated unnecessarily, while normal reception can be performed stably. For a finger that is not present, the update cycle is shortened, and the path timing is frequently reviewed.

Therefore, according to the mobile radio terminal having the above configuration, the re-allocation cycle of the reception path is set short only for the fingers that cannot perform normal reception stably. Improved,
The load required for the reallocation process is unlikely to increase.

Next, a third embodiment of the present invention will be described. FIG. 5 shows a configuration of a mobile wireless terminal device according to the third embodiment of the present invention.

The A / D converter 21 performs A / D conversion and sampling of the received signal received through the antenna 20, and converts the received baseband signal obtained by the A / D conversion into 22a.
To the respective matched filters 23, 24, and 25.

The matched filter 22a detects all receivable paths from the spread signal in the received baseband signal, measures the power of each detected path, and compares the detected / measured result with the received power. Output to the accumulator 29.

The matched filter 22a specifies one path suitable for reception among the detected paths, and controls the reception power of the specified path in response to a request from the control unit 28a described later. Notify the unit 28a.

The received power accumulating section 29 includes a control section 28 described later.
a during the time Tm set by the
The received power input from “a” is accumulated for each path, and the accumulated result is output to the path search unit 26.

The path search section 26 includes a reception power accumulation section 29
Monitor the received power for each path accumulated in
A path having a large received power is set as a candidate path, and a phase in a path slot (hereinafter, referred to as path timing) indicating the despread timing of the candidate path is notified to the path allocating unit 27.

The path allocator 27 includes a finger 23 to be described later.
Monitor the received power of the demodulation results of ~ 25, and
When a finger whose received power is lower than a preset threshold level occurs, a path timing of a path not allocated to any finger among the candidate paths is allocated to the finger.

Fingers 23 to 25 despread and demodulate the received baseband signal at the path timing allocated by path allocating section 27, and demodulate the demodulated result in the subsequent RA.
It outputs to the KE combining unit (not shown) and the path allocating unit 27.

The control unit 28a includes a reception power memory 281a
The reception power of the path specified by the matched filter 22a is read for a predetermined time, and is recorded in the reception power memory 281a. Then, the control unit 28a, based on the information stored in the reception power memory 281a,
The received power accumulation unit 29 controls the accumulated time Tm of the received power.

Next, the operation of controlling the accumulated time Tm of the received power in the received power accumulating section 29 of the mobile radio terminal having the above configuration will be described. FIG. 6 is a flowchart showing this control operation, which is a process performed by the control unit 28a.

First, in step 6a, the processing for reading the received power at the path timing specified by the matched filter 22a, recording the received power in the received power memory 281a, and proceeds to step 6b.

At step 6b, it is determined whether a predetermined time T has elapsed. Here, if the predetermined time T has elapsed, the process proceeds to step 6c, and if not, the process waits in step 6b.

At step 6c, the recording process of the received power started at step 6a is completed, and the routine goes to step 6d. In step 6d, the fluctuation of the received power recorded in the received power memory 281a is verified, the number N of points indicating the maximum is counted, and the process proceeds to step 6e.

In step 6e, it is determined whether N counted in step 6d is smaller than a preset threshold value Nmin. Here, when N is smaller than the threshold value Nmin, the process proceeds to step 6h, and when N is equal to or larger than the threshold value Nmin, the process proceeds to step 6f.

At step 6f, it is determined whether or not N counted at step 6d is larger than a preset threshold value Nmax (> Nmin). Here, if N is larger than the threshold value Nmax, the process proceeds to step 6g. On the other hand, if N is smaller than the threshold value Nmax, the process ends without changing the accumulated time Tm.

In step 6g, the accumulated time Tm is reduced from the current value by the variable width Ti, and the process ends. Note that the accumulated time Tm is already the accumulated minimum time Tmi.
If it is n, it is not reduced.

On the other hand, in step 6h, the accumulated time Tm is increased from the current value by the variable width Ti, and the process is terminated. Note that the accumulated time Tm is already the accumulated maximum time T
If it is max, it is not increased.

As described above, in the mobile radio terminal having the above configuration, when the fluctuation of the received power of the predetermined path is small, the accumulated time Tm of the matched filter 22a is extended,
On the other hand, when the fluctuation of the received power of the predetermined path is large,
The accumulated time Tm of the matched filter 22a is reduced.

Therefore, according to the mobile radio terminal having the above-described configuration, the matched filter 2 can be changed according to the change of the reception environment.
By varying the accumulated time of 2a, priority is given to following a path change or to improvement of reception characteristics. Therefore, it is possible to cope with changes in the reception environment and maintain good reception characteristics. .

The present invention is not limited to the above embodiment. For example, in the above embodiment, the optimal path is determined and assigned to all the fingers 23 to 25 based on the received power accumulated at the same accumulated time Tm. However, the present invention is not limited to this. ,
For example, a modified example as shown in FIG. 7 can be considered.

FIG. 7A shows that the finger 23 is
The optimum path is determined based on the received power accumulated in the longest accumulated time Tmax, and for the finger 25, the shortest accumulated time Tmax is determined.
The optimum path is determined based on the received power accumulated in min, and the optimum path is determined only for the finger 24 based on the received power accumulated in the variable accumulation time Tm.

FIG. 7B shows all the fingers 23-2.
In 5, the optimum path is determined based on the received power accumulated at the variable accumulated time Tm, but the accumulated time Tm is varied independently for each finger.

FIG. 7C shows all the fingers 23-2.
In 5, the optimum path is determined based on the received power accumulated by the variable accumulated time Tm. The independent longest accumulated time Tmax and the shortest accumulated time Tmin are set independently for each finger, and the accumulated time is set in each variable range. Tm is made variable.

Next, a fourth embodiment of the present invention will be described. FIG. 8 shows a configuration of a mobile wireless terminal device according to the fourth embodiment of the present invention.

The A / D converter 21 performs A / D conversion and sampling of the received signal received through the antenna 20, and converts the received baseband signal obtained by the A / D conversion into 22b.
To the respective matched filters 23, 24, and 25.

The matched filter 22b detects all receivable paths from the spread signal in the received baseband signal, measures the power of each detected path, and compares the detected / measured result with the received power. Output to the accumulator 29.

[0098] The received power accumulating section 29 includes a control section 28 described later.
b during the time Tm set by the b.
The received power input from b is accumulated for each path, and the accumulated result is output to the path search unit 26.

The path search section 26 includes a received power accumulating section 29
Monitor the received power for each path accumulated in
A path having a large received power is set as a candidate path, and a phase in a path slot (hereinafter, referred to as path timing) indicating the despread timing of the candidate path is notified to the path allocating unit 27.

The path allocating unit 27 includes a finger 23 to be described later.
Monitor the received power of the demodulation results of ~ 25, and
When a finger whose received power is lower than a preset threshold level occurs, a path timing of a path not allocated to any finger among the candidate paths is allocated to the finger.

Fingers 23 to 25 despread and demodulate the received baseband signal at the path timing allocated by path allocating section 27, and demodulate the demodulated result in the subsequent RA.
It outputs to the KE combining unit (not shown) and the path allocating unit 27.

The speed detecting means 200b detects the moving speed V of the mobile radio terminal device and notifies the control unit 28b. The control unit 28b includes a speed information memory 281b,
During a predetermined time, the moving speed V detected by the speed detecting means 200b is read and recorded in the speed information memory 281b. Then, the control unit 28b controls the accumulated time Tm of the received power in the received power accumulating unit 29 based on the information stored in the speed information memory 281b.

Next, the operation of controlling the accumulated time Tm of the received power in the received power accumulating section 29 of the mobile radio terminal having the above configuration will be described. FIG. 9 is a flowchart showing this control operation, which is a process performed by the control unit 28b.

First, in step 9a, the speed detecting means 2
The moving speed V detected at 00b is read, recorded in the speed information memory 281b, and the process proceeds to step 9b. In step 9b, it is determined whether or not the moving speed V recorded in the speed information memory 281b is smaller than a preset threshold value Vmin. Here, the moving speed V is equal to the threshold Vmi.
If n is smaller than n, the process goes to step 9e.
If the moving speed V is equal to or higher than the threshold value Vmin, step 9
Move to c.

At step 9c, it is determined whether or not the moving speed V is higher than a preset threshold value Vmax (> Vmin). Here, if the moving speed V is larger than the threshold value Vmax, the process proceeds to step 9d.
Is smaller than the threshold value Vmax, the processing is terminated without changing the accumulated time Tm.

In step 9d, the accumulated time Tm is reduced from the current value by the variable width Ti, and the process ends. Note that the accumulated time Tm is already the accumulated minimum time Tmi.
If it is n, it is not reduced.

On the other hand, in step 9e, the accumulated time Tm is increased from the current value by the variable width Ti, and the process is terminated. Note that the accumulated time Tm is already the accumulated maximum time T
If it is max, it is not increased.

As described above, in the mobile radio terminal having the above configuration, when the mobile radio terminal is moving at a high speed, the accumulated time Tm of the matched filter 22a is extended. When the speed is low, the accumulated time Tm of the matched filter 22a is reduced.

Therefore, according to the mobile radio terminal having the above configuration, by varying the accumulated time of the matched filter 22a in accordance with the moving speed of the mobile radio terminal, priority is given to following the path change, and Because we prioritize the improvement of characteristics, we can respond to changes in the reception environment,
Good receiving characteristics can be maintained.

The present invention is not limited to the above embodiment. For example, in the above-described embodiment, the optimal path is determined and assigned to all the fingers 23 to 25 based on the received power accumulated at the same accumulation time Tm. Similarly,
A modification as shown in FIG. 8 can be applied.

Next, a fifth embodiment of the present invention will be described. FIG. 10 shows a configuration of a mobile wireless terminal device according to the fifth embodiment of the present invention.

The A / D converter 21 performs A / D conversion and sampling of the received signal received through the antenna 20, and converts the received baseband signal obtained by the A / D conversion into 22c.
To the respective matched filters 23, 24, and 25.

The matched filter 22c detects all receivable paths from the spread signal in the received baseband signal, measures the power of each detected path, and compares the detected / measured result with the received power. Output to the accumulator 29.

The received power accumulating section 29 includes a control section 28 described later.
c during the time Tm set by the matched filter 22.
The received power input from c is accumulated for each path, and the accumulated result is output to the path search unit 26.

The path search section 26 includes a received power accumulating section 29
Monitor the received power for each path accumulated in
A path having a large received power is set as a candidate path, and a phase in a path slot (hereinafter, referred to as path timing) indicating the despread timing of the candidate path is notified to the path allocating unit 27.

The path allocating unit 27 includes a finger 23 to be described later.
Monitor the received power of the demodulation results of ~ 25, and
When a finger whose received power is lower than a preset threshold level occurs, a path timing of a path not allocated to any finger among the candidate paths is allocated to the finger.

Fingers 23 to 25 despread and demodulate the received baseband signal at the path timing allocated by path allocating section 27 and demodulate this demodulated result to the subsequent RA.
It outputs to the KE combining unit (not shown) and the path allocating unit 27.

The cell detecting means 200c detects the identification information C of the cell (wireless zone) where the radio base station connected to the mobile radio terminal is connected, and notifies the control unit 28c. The control unit 28c includes a cell information memory 281c,
The cell information C detected by the cell detection means 200c is read at a predetermined cycle and recorded in the cell information memory 281c. The cell information memory 281c stores up to N pieces of cell information C
Can be stored.

Further, the control unit 28c controls the movement information memory 2
82c, and determines whether or not the mobile radio terminal device is moving at high speed based on information stored in the cell information memory 281c, and records the determination result (movement mode) in the movement information memory 282c. I do. Then, the control unit 28c controls the accumulated time Tm of the received power in the received power accumulating unit 29 based on the mode information recorded in the movement information memory 282c.

Next, the operation of controlling the accumulated time Tm of the received power in the received power accumulating section 29 of the mobile radio terminal having the above configuration will be described. FIG. 11 is a flowchart showing this control operation, which is a process executed by the control unit 28c every time a predetermined cycle arrives.

First, in step 11a, the identification information C of the cell detected by the cell detecting means 200c is read, and
The data is recorded in the cell information memory 281c, and the process proceeds to step 11b. Here, when the cell information memory 281c has already stored N pieces of cell information C, the oldest recorded information is deleted and the latest cell information C is recorded.

In step 11b, the cell information memory 28
1c with reference to the cell information stored in
When the number is stored, it is determined that the object is moving at a high speed (high-speed mode), and otherwise, it is determined that the object is moving at a low speed (low-speed mode). After recording in 282c, step 11c
Move to

In step 11c, the movement information memory 28
2c, the previous travel mode and the current step 1
It is determined whether or not the movement mode determined in 1b has changed. If the movement mode has changed, that is, if the mode has changed from the high-speed mode to the low-speed mode or from the low-speed mode to the high-speed mode, step 11d is executed.
Move to On the other hand, if there is no change in the travel mode,
The process ends.

In step 11d, the movement information memory 28
Referring to 2c, it is determined whether or not the current travel mode is the high-speed mode. Here, in the case of the high-speed mode, the process proceeds to step 11e. On the other hand, in the case of the low-speed mode,
Move to step 11f.

In step 11e, the accumulated time Tm is increased from the current value by the variable width Ti, and the process ends. Note that the accumulated time Tm is already the accumulated maximum time Tma
If it is x, it is not increased.

On the other hand, in step 11f, the accumulated time Tm
Is decreased from the current value by the variable width Ti, and the process is terminated. If the cumulative time Tm has already reached the cumulative minimum time Tmin, it is not reduced.

As described above, in the mobile radio terminal having the above configuration, when the mode changes from the high-speed mode to the low-speed mode, the accumulated time Tm of the matched filter 22a is extended,
On the other hand, when changing from low-speed mode to high-speed mode,
The accumulated time Tm of the matched filter 22a is reduced.

Therefore, according to the mobile radio terminal having the above-described configuration, by following the change in the accumulated time of the matched filter 22a in accordance with the change in the moving speed of the mobile radio terminal, priority is given to following the path change. Since the priority is given to the improvement of the reception characteristics, it is possible to cope with a change in the reception environment and maintain the good reception characteristics.

Note that the present invention is not limited to the above embodiment. For example, in the above-described embodiment, the optimal path is determined and assigned to all the fingers 23 to 25 based on the received power accumulated at the same accumulation time Tm. Similarly,
A modification as shown in FIG. 8 can be applied.

Next, a sixth embodiment of the present invention will be described. FIG. 12 shows a configuration of a mobile wireless terminal device according to the sixth embodiment of the present invention.

The A / D converter 31 performs A / D conversion and sampling of the reception signal received through the antenna 30, and converts the reception baseband signal obtained by the A / D conversion into 32 matched filters and 33, 34, 35. Output to each finger.

The matched filter 32 detects all receivable paths from the spread signal in the received baseband signal, measures the power of each detected path, and compares the detected / measured result with the received power. Output to the accumulator 39.

The received power accumulating section 39 operates during the time Tm1,
The received power input from the matched filter 32 is accumulated for each path, and the accumulated result is output to the path search unit 36. In parallel with this, the time Tm2 (<Tm1)
During this period, the received power input from the matched filter 32 is accumulated for each path, and the accumulated result is stored in the path search unit 36.
Output to

The path search section 36 includes a received power accumulating section 39
Monitor the received power for each path accumulated only during the time Tm1.
a1, a phase in a path slot (hereinafter referred to as path timing) Ph indicating the despread timing of the candidate path
1 is notified to the path assignment unit 37.

In parallel with this, the path search unit 36 monitors the received power of each path accumulated by the received power accumulating unit 39 only during the time Tm2, and among these, the path having the large received power is determined. A candidate path Pa2 is set, and a path slot phase Ph2 indicating the despread timing of the candidate path is notified to the path allocating unit 37.

The path allocating unit 37 includes a finger 3 to be described later.
The received power of the demodulation results of 3, 34 is monitored, and when a finger whose received power is less than a preset threshold level occurs for a predetermined time or more, the finger is not allocated to any of the fingers of the candidate path Pa1. The path timing of the path is assigned to the finger.

The path allocating unit 37 monitors the received power of the demodulated result of the finger 35, which will be described later, and when the received power is lower than a predetermined threshold level for a predetermined time or more, the path of the candidate path Pa2 is determined. , The path timing of the path not assigned to any finger
Assign to

Fingers 33 to 35 despread and demodulate the received baseband signal at the path timing allocated by path allocating section 37, and demodulate the demodulated result in the subsequent RA.
It outputs to the KE combining unit (not shown) and the path allocating unit 37.

Next, with reference to FIG. 13, a description will be given of a path allocating operation for the fingers 33, 34, 35 of the mobile radio terminal having the above configuration. First, finger 33,
The operation of assigning a path to the path 34 will be described.

The reception power accumulating section 39 includes the fingers 33 and 3
In order to allocate a path to the path No. 4, the received power input from the matched filter 32 is accumulated for each path every time Tm1, and the accumulated result is output to the path search unit.

On the other hand, the path search unit 36 monitors the received power for each path accumulated for the time Tm1 by the received power accumulating unit 39, and among the paths, the path having the large received power is selected as the candidate path Pa1. The phase Ph1 in the path slot indicating the despread timing of this candidate path is
Notify to

In the path allocating section 37, the fingers 33, 34
Monitoring the received power of the demodulation result of
It is determined whether or not any finger whose received power is lower than a preset threshold level has not occurred.

In the meantime, when a finger whose received power becomes lower than the preset threshold level occurs, among the candidate paths Pa1 detected by the path search unit 36, a path of a path not allocated to any finger. Timing
Assigned to fingers whose received power level is less than the threshold.

In parallel with the path allocating operation for the fingers 33 and 34, the path allocating operation for the finger 35 is performed. Hereinafter, a path assignment operation for the finger 35 will be described.

The received power accumulating section 39 accumulates, for each path, the received power input from the matched filter 32 for each path Tm2 for path assignment to the finger 35, and accumulates the accumulated result in the path search section 36. Output to

On the other hand, the path search unit 36 monitors the received power of each path accumulated for the time Tm2 by the received power accumulating unit 39, and among the paths, the path having the large received power is determined as the candidate path Pa2. And the phase Ph2 in the path slot indicating the despread timing of this candidate path
Notify to

The path allocating unit 37 monitors the received power of the demodulated result of the finger 35, and determines whether or not the received power by the finger 35 is lower than a predetermined threshold level for a predetermined time or more. .

When the above state occurs, the candidate path Pa2 detected by the path search unit
The path timing of a path not assigned to any finger is assigned to the finger 35.

As described above, in the mobile radio terminal having the above-described configuration, when the path allocating unit 37 allocates the optimal path to the fingers 33 to 35, the fingers 33 and 34 of the matched filter 32 are accumulated in the accumulated time Tm1. The optimum path is detected based on the result of accumulating the output, and the path is allocated.

On the other hand, for the finger 35, the optimum path is detected based on the result of accumulating the output of the matched filter 32 at the accumulation time Tm2, and the path is assigned.

That is, the optimum path is detected between the fingers 33 and 34 and the finger 35 based on the result obtained by accumulating the outputs of the matched filter 32 at different accumulation times.

Therefore, according to the mobile radio terminal having the above configuration, the optimum path can be selected in an environment where the path and the reception power fluctuate relatively slowly, and the optimum path can be selected even in an environment where the path and the reception power fluctuate rapidly. Since a path can be selected, good reception characteristics can be maintained in various reception environments.

Note that the present invention is not limited to the above embodiment. For example, in the above-described embodiment, three fingers are described, but the number is not limited thereto. It goes without saying that various modifications can be made without departing from the spirit of the present invention.

[0154]

As described above, according to the present invention, the received power level is monitored from the demodulation result, the finger whose reception path needs to be changed is detected, and a new path timing is detected only for the detected finger. We are trying to assign.
That is, for the finger for which the normal reception is performed, the path timing is not updated unnecessarily.

Therefore, according to the present invention, there is provided a mobile radio terminal capable of preventing an increase in the load required for the reassignment process even if the reassignment cycle of the reception path is shortened in order to improve reception characteristics. it can.

Further, according to the present invention, the path updating cycle is set for each receiver, and the receiving path is updated. Therefore, according to the present invention, it is possible to select an optimal path in an environment where the path or the reception power fluctuates relatively slowly by the finger whose update cycle is set to be long, and the path is rapidly set by the finger whose update cycle is set to be short Therefore, it is possible to provide a mobile radio terminal capable of maintaining good reception characteristics in various reception environments because an optimum path can be selected even in an environment where reception power varies.

Further, according to the present invention, the accumulated time of the received power level, which is used as a criterion for the path detection in the path detecting means, is varied according to the fluctuation of the received power level.

Therefore, according to the present invention, it is possible to provide a mobile radio terminal capable of maintaining a good reception characteristic in response to a change in the reception environment caused by a change in the reception power level.

Further, according to the present invention, the accumulated time of the received power level, which is used as a criterion for path detection in the path detecting means, is varied according to the moving speed of the mobile radio terminal. Therefore, according to the present invention, it is possible to provide a mobile radio terminal that can maintain good reception characteristics in response to a change in the reception environment that appears in a change in the moving speed.

Further, according to the present invention, according to the change of the base station to which the mobile radio terminal is connected, the path detection means varies the accumulated time of the reception power level used as a criterion for path detection. I have.

Therefore, according to the present invention, it is possible to provide a mobile radio terminal capable of maintaining a good reception characteristic in response to a change in the reception environment that appears due to a change in the connected base station.

According to the present invention, the reception power level, which is used as a criterion for path detection in the path detection means, is accumulated at a plurality of different accumulation periods, and based on the accumulation result,
A path suitable for reception is determined and assigned to a receiver.

Therefore, according to the present invention, the receiver to which the optimal path detected based on the received power level accumulated in the long accumulation cycle is allocated can be used in an environment where the path and the received power fluctuate relatively slowly. A receiver that can receive the optimal path and assigns the optimal path detected based on the received power level accumulated in a short accumulation period allows the optimal path to be received even in an environment where the path and received power fluctuate rapidly. Therefore, it is possible to provide a mobile radio terminal capable of maintaining good reception characteristics in various reception environments.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram showing a configuration of a first embodiment of a mobile wireless terminal device according to the present invention.

FIG. 2 is a flowchart illustrating a reception path allocation control operation of the mobile wireless terminal device shown in FIG. 1;

FIG. 3 is a circuit block diagram showing a configuration of a second embodiment of the mobile wireless terminal device according to the present invention.

FIG. 4 is a flowchart for explaining a reception path allocation control operation of the mobile wireless terminal device shown in FIG. 3;

FIG. 5 is a circuit block diagram showing a configuration of a third embodiment of the mobile wireless terminal device according to the present invention.

FIG. 6 is a flowchart for explaining a control operation of a cumulative time of the received power in the received power accumulating section of the mobile wireless terminal device shown in FIG. 5;

FIG. 7 is a view for explaining a modification of the mobile wireless terminal device shown in FIGS. 5, 8, and 10;

FIG. 8 is a circuit block diagram showing a configuration of a fourth embodiment of the mobile wireless terminal device according to the present invention.

9 is a flowchart for explaining a control operation of a cumulative time of the received power in the received power accumulating section of the mobile wireless terminal device shown in FIG.

FIG. 10 is a circuit block diagram showing the configuration of a fifth embodiment of the mobile wireless terminal device according to the present invention.

FIG. 11 is a flowchart illustrating a control operation of a cumulative time of the received power in the received power accumulating unit of the mobile wireless terminal device shown in FIG.

FIG. 12 is a circuit block diagram showing a configuration of a sixth embodiment of the mobile wireless terminal device according to the present invention.

13 is a flowchart for explaining a reception path allocation control operation of the mobile wireless terminal device shown in FIG.

[Explanation of symbols]

10, 20, 30 ... Antenna 11, 21, 31 ... A / D converter 12, 22a, 22b, 22c, 32 ... Matched filter 13-15, 23-25, 33-35 ... Finger 16, 26, 36 ... Path search units 17a, 17b, 27, 37 ... path allocation units 18a, 18b, 28a, 28b, 28c ... control units 181a ... reception power memory 181b ... allocation cycle memory 182a, 182b ... path timing memory 281a ... reception power memory 281b ... Speed information memory 281c Cell information memory 282c Moving information memory 29, 39 Received power accumulating unit 200b Speed detecting means 200c Cell detecting means

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[Procedure amendment]

[Submission date] April 19, 2000 (2004.1.
9)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 9

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction contents]

Furthermore, the present invention according to claim 9 provides:
In a mobile radio terminal that adopts a direct spread spectrum spreading method and performs Rake reception using a plurality of receivers, a despreading process of multiplying a received signal frequency-converted into a baseband signal by a spreading code at various timings is performed. Despreading means for detecting the signal strength of the receivable path and the timing of despreading, and for each receivable path detected by the despreading means, accumulates the signal strength at a predetermined accumulation cycle,
Path detection means for detecting a path suitable for reception from the accumulated result, reception power levels of signals demodulated by a plurality of receivers, power level detection means for detecting for each receiver,
A moving speed detecting means for detecting a moving speed of the mobile radio terminal, a cumulative cycle variable means for monitoring a detection result of the moving speed detecting means, and changing a cumulative cycle in the path detecting means in accordance with a change in the moving speed; Is provided.

Claims (15)

[Claims] 1. A mobile radio terminal adopting a direct spread spectrum spreading method and performing Rake reception using a plurality of receivers, multiplies a reception signal frequency-converted into a baseband signal by a spread code at various timings. Apply the inverse diffusion process,
Path detection means for detecting a path suitable for reception; power level detection means for detecting the reception power level of the signal demodulated by the plurality of receivers for each receiver; detection of the power level detection means Monitoring the result, if the received power level falls below a preset threshold,
For a receiver that demodulates the signal of this received power level,
A mobile radio terminal comprising: a path allocating unit that allocates a new path detected by the path detecting unit. 2. A mobile radio terminal adopting a direct spread spectrum spreading method and performing Rake reception using a plurality of receivers, multiplies a reception signal frequency-converted into a baseband signal by a spread code at various timings. Apply the inverse diffusion process,
A path detection unit that detects a path suitable for reception; a power level detection unit that detects a reception power level of a signal demodulated by the plurality of receivers for each of the receivers; A detection result of the power level detection means is monitored at a preset update cycle, and a new path detected by the path detection means for a receiver whose received power level is lower than a preset threshold value. And a path allocating unit for allocating the mobile terminal. 3. A path storage means for storing identification information of a path allocated by the path allocation means for each of the plurality of receivers, and the path information is stored on the basis of the path identification information stored in the path storage means. 3. The mobile radio terminal according to claim 2, further comprising: an update cycle changing unit that changes an update cycle of the allocating unit. 4. The update cycle variable means, based on the path identification information stored in the path storage means, determines a receiver to which a predetermined number of paths having the same identification information are continuously allocated. 4. The mobile radio terminal according to claim 3, wherein the mobile radio terminal detects the reception, and extends an update cycle of the path allocating means corresponding to the detected receiver. 5. The update cycle changing means, based on path identification information stored in the path storage means, determines a receiver to which a predetermined number or more of paths having the same identification information are allocated without being consecutive. 4. The mobile radio terminal according to claim 3, wherein the mobile radio terminal detects, and shortens an update cycle of the path allocating means corresponding to the detected receiver. 6. A mobile radio terminal adopting a direct spread spectrum spreading method and performing Rake reception using a plurality of receivers, multiplies a received signal frequency-converted into a baseband signal by a spread code at various timings. Apply the inverse diffusion process,
Despreading means for detecting the signal strength of the receivable path and the timing of the despreading; and for each receivable path detected by the despreading means, accumulating the signal strength at a predetermined accumulation cycle, A path detection unit that detects a path suitable for reception from, a power level detection unit that detects a reception power level of a signal demodulated by the plurality of receivers for each receiver, and a power level detection unit. A mobile radio terminal, comprising: a cumulative cycle variable unit that monitors a detection result and varies a cumulative cycle in the path detecting unit according to a change in the received power level. 7. The cumulative period variable unit monitors a detection result of the power level detecting unit, and shortens the cumulative period of the path detecting unit when the received power level fluctuates more than a preset level. The mobile radio terminal according to claim 6, wherein 8. The cumulative cycle variable unit monitors a detection result of the power level detecting unit, and when a change in the received power level is stable to a predetermined level or more,
7. The mobile radio terminal according to claim 6, wherein an accumulation period in said path detection means is extended. 9. A mobile radio terminal adopting a direct spread spectrum spreading method and performing Rake reception using a plurality of receivers, multiplies a reception signal frequency-converted into a baseband signal by a spread code at various timings. Apply the inverse diffusion process,
Despreading means for detecting the signal strength of the receivable path and the timing of the despreading; and for each receivable path detected by the despreading means, accumulating the signal strength at a predetermined accumulation cycle, A path detection unit that detects a path suitable for reception from a power level detection unit that detects a reception power level of a signal demodulated by the plurality of receivers for each of the receivers; A detection result is monitored, and a new path detected by the path detecting means is assigned to a receiver whose received power level is lower than a preset threshold, and the receiver receives the new path. A path allocating unit; a moving speed detecting unit that detects a moving speed of the mobile radio terminal; a detection result of the moving speed detecting unit, which is monitored by the path detecting unit according to a change in the moving speed. Mobile radio terminal characterized by and a cumulative period varying means for varying the cumulative period. 10. The cumulative cycle variable means monitors the detection result of the moving speed detecting means, and shortens the cumulative cycle in the path detecting means when the moving speed increases to a value equal to or greater than a preset value. The mobile radio terminal according to claim 9, wherein: 11. The cumulative cycle variable means monitors the detection result of the moving speed detecting means, and extends the cumulative cycle in the path detecting means when the moving speed is reduced to a value equal to or greater than a preset value. The mobile radio terminal according to claim 9, wherein: 12. A mobile radio terminal adopting a direct spread spectrum spreading method and performing Rake reception using a plurality of receivers, multiplies a received signal frequency-converted into a baseband signal by a spread code at various timings. Apply the inverse diffusion process,
Despreading means for detecting the signal strength of the receivable path and the timing of the despreading; and for each receivable path detected by the despreading means, accumulating the signal strength at a predetermined accumulation cycle, A path detecting means for detecting a path suitable for reception from a mobile station, a base station detecting means for detecting a base station connected to the mobile radio terminal at a predetermined cycle, and monitoring a detection result of the base station detecting means. A mobile radio terminal comprising: a cumulative cycle varying unit that varies the cumulative cycle of the path detecting unit according to a change in identification information of a connected base station. 13. The accumulation period variable unit monitors a detection result of the base station detection unit, and when a change in identification information of a connected base station is more than a predetermined level, the path detection unit. 13. The mobile radio terminal according to claim 12, wherein a cumulative period in the mobile terminal is shortened. 14. The cumulative cycle variable unit monitors a detection result of the base station detecting unit, and when a change in identification information of a connected base station is stable at a predetermined level or more, 13. The mobile radio terminal according to claim 12, wherein an accumulation period in the path detection unit is extended. 15. A mobile radio terminal adopting a direct spread spectrum spreading method and performing Rake reception using a plurality of receivers, multiplies a reception signal frequency-converted into a baseband signal by a spread code at various timings. Apply the inverse diffusion process,
Despreading means for detecting the signal strength of the receivable path and the timing of despreading, and the signal strength of the receivable path detected by the despreading means are accumulated at a plurality of different accumulation periods, and from this accumulation result A mobile radio terminal, comprising: a path detecting unit that detects a path suitable for reception; and a path allocating unit that allocates a new path detected by the path detecting unit at a preset allocation cycle.