JP2001251212A - Finger assignment system and mobile communication apparatus using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a finger assignment system with which occurrence of a momentary interruption is prevented at movement of a mobile communication apparatus, at multi-path or at synthesis of data received from a plurality of areas, to avoid a momentary interrupt operation, where an image is momentarily stopped through the change in the assignment of a path during image communication. SOLUTION: A searcher 3 monitoring the occurrence of a multi-path directly informs each of fingers 41-4n and a RAKE synthesis section 5 about the assignment of a path. Thus, reception timing taking the occurrence of a multi-path into account about which the searcher 3 informs each finger via a timing control section 2, information (valid/invalid information) denoting whether each finger receives data, codes used by each finger to apply inverse spread processing to the received data and combination of the fingers outputs of which the RAKE synthesis section 5 synthesizes, can all be switched at the same time, the occurrence of instantaneous break can be prevented as a result.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a finger assignment system and a mobile communication device using the same, and more particularly to a W-CDM.
The present invention relates to a finger assignment system in a mobile communication device such as an A-type wireless telephone device.

[0002]

2. Description of the Related Art Recently, CDMA (Code Division Multip
The mobile phone called the “le Access” method has begun to spread. One of the features is that, for example, waves in up to three areas are simultaneously received and combined to make it difficult to disconnect a call. Also, in each of the three areas, the waves that arrive with a time delay are received by a so-called FINGER, even in the case of multipath phenomena such as the radio wave reaching the mobile device directly or reaching the building after being slightly reflected. Another feature is that the reception sensitivity is increased by receiving and demodulating the signal with a receiver.

However, strictly speaking, when an area to be received is added or deleted, more specifically, at the moment when the assignment of the wave being received by each finger changes, a certain time (about 10 msec) is accurate. And the demodulated outputs of these fingers cannot be combined. In this case, because of the short time of 10 msec, in the case of voice, no inconvenience is perceived by the ears of the person actually using the sound, but in the case of non-restricted information such as a videophone call, even in the time of 10 msec. Since the image freezes momentarily, the user also feels trouble.

[0004] Such a phenomenon will be described with reference to FIGS. Referring to FIG. 3, a reception signal from an antenna is subjected to RF reception processing by an RF unit 1 and is subjected to A / D (analog / digital) conversion processing to be converted into a digital signal. The timing control unit 2 supplies a reference clock to hardware of the entire apparatus, and a searcher 3.
Is given to the reference clock by
It supplies to each finger 41-4n. The searcher 3 monitors the amount of delay in the reception timing due to the movement of the mobile communication device, a plurality of paths in the multipath propagation signal due to the reflection of a building or the like.
The multipath of the perch channel of each area is monitored, and the correction value (delay amount) of the reception timing of each finger 41 to 4n is reported to the timing control unit 2. Further, the searcher 3 obtains path valid / invalid information indicating the validity of path reception for each finger and a branch (area number) indicating which code should be used for despreading (demodulating), and
(Control device) 7 is notified.

[0005] Each of the fingers 41 to 4n performs a despreading process by using a predetermined spreading code for each area to take out a signal before spreading (one of the features of the CDMA system is "spreading. Means that data to be transmitted is scrambled with a certain code, whereas the receiving side can extract only data by performing despreading using the code used at the time of transmission. ).

The CPU 7 determines, for each of the fingers 41 to 4n, which of the three despreading codes corresponding to each of the three areas at maximum, which despreading code is to be used. These fingers 41 to 4n are notified based on path information such as invalid information and branch numbers. The despread output by these fingers 41-4n is R
RAKE synthesis is performed by the AKE synthesis unit 5 and decoding processing is performed by the Viterbi decoding unit 6.

FIG. 4 is a flowchart showing the operation of the finger assignment processing in the block of FIG. During the call, the searcher 3 monitors the multipath of the perch channel, and enters the “finger allocation state” in a cycle for updating the path allocation (step S1). In response to the arrival of the update cycle for changing the path assignment, the searcher 3 instructs the timing control unit 2 with each of the fingers 41 to 4n.
The amount of delay between the multipath component and the reference perch channel reception timing is acquired and reported for each time, and to the CPU 7, path reception valid / invalid information for each finger and which code should be used for despreading. The branch (area) number is notified (step S2).

The timing controller 2 supplies a clock pulse indicating the reception timing to each of the fingers 41 to 4n based on the delay amount from the searcher 3 (step S).
3). The CPU 7 sets the valid / invalid information and the branch number of each finger 41 to 4n acquired from the searcher 3 to each finger and the RAKE combining unit 5 (step S).
7).

In each finger, a despreading process is performed in synchronization with a new clock pulse after updating the timing assignment from the timing controller 2 (step S4). RA
The KE combining unit 5 combines the received data from the fingers (step S5), and the Viterbi decoding unit 6 performs RAKE
The output data from the synthesizing unit 5 is subjected to Viterbi decoding (step S6).

[0010]

As described above, in the conventional method, the setting of the path valid / invalid information and the branch number set via the CPU 7 is performed by the clock for the reception timing set by the timing control unit 2. The maximum delay is 10 msec from the pulse setting. Therefore, during the frame (10 msec), the reception timing and the despreading code of the fingers 41 to 4n are inconsistent, and a temporary momentary interruption occurs.

As a synthesis procedure in the RAKE synthesis section 5, first, multipath components for each branch are synthesized,
After that, synthesis is performed for each branch, and the branch number is also set for the RAKE synthesis unit 5 via the CPU 7. A momentary interruption will occur.

An object of the present invention is to prevent movement of a mobile communication device, multipath, and instantaneous interruption when combining received data from, for example, up to three areas, and to allocate a path during image communication. It is an object of the present invention to provide a finger assignment method and a mobile communication device using the same, which can prevent an instantaneous interruption operation in which an image stops for a moment.

[0013]

According to the present invention, each path information of a plurality of paths in a multipath propagation signal is obtained by a searcher, and the received signals of the plurality of paths are respectively demodulated according to the path information. A finger assignment method in a mobile communication device for assigning fingers, wherein the path information is directly supplied from the searcher to each of the fingers is obtained.

The path information includes validity / invalidity information indicating the validity of the path, and a service area area number of the mobile communication device, and combines the demodulated outputs from the fingers. The path information is also supplied directly from the searcher to the combining means. Further, the searcher periodically acquires the path information.

The operation of the present invention will be described. The searcher monitoring the multipath notifies each finger and the RAKE combining unit of the path assignment directly. By doing so, the reception timing in consideration of the multipath notified to each finger from the searcher via the timing control unit, which has conventionally occurred when the path assignment is changed, and whether or not each finger receives Information (valid /
Invalid information), codes that each finger despreads received data, and combinations of fingers that are combined by the RAKE combining unit can all be switched at the same time. It is possible to prevent instantaneous interruption when combining data received from the area. Therefore, it is possible to effectively prevent an instantaneous interruption operation in which an image is temporarily stopped due to a change in path assignment during image communication such as a videophone call.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention, and the same parts as those in FIG. 3 are denoted by the same reference numerals. As shown in FIG. 1, the embodiment of the present invention includes an RF unit 1, a timing control unit 2, a searcher 3
And a plurality of fingers 41 to 4n and a RAKE combining unit 5
, A Viterbi decoding unit 6 and a CPU 7. FIG. 1 shows the configuration of hardware related only to the receiving system, and the transmitting system is not particularly described because it is not related to the present invention.

The RF unit 1 is a radio unit, and is a block that converts received analog data into digital data and converts digital data into analog data. Timing control unit 2
Provides a reference clock to the hardware of the entire apparatus. Note that the clock is transmitted in consideration of a correction value that is a delay amount caused by the searcher 3.

A base station (not shown) constantly generates a perch channel specific to an area, and transmits information on the area to the mobile communication device. The mobile communication device operates in synchronization with the timing of the perch channel as a reference timing, and the timing control unit 2 transmits a frame of the perch channel (10 ms) to each hardware.
The clock is provided every ec).

The searcher 3 monitors the amount of delay in the reception timing due to the movement of the mobile communication device and the multipath due to the reflection of a building or the like. At the time of handover, for example, the multipath of a maximum of three perch channels is monitored. Then, each finger reports the correction value of the reception timing to the timing control unit 2. Each of the fingers 4 to 4n is a receiver that performs a receiving process in synchronization with a clock from the timing control unit 2. Each finger performs a despreading process using a spreading code predetermined for each area, and extracts and demodulates a signal before spreading.

Conventionally, as described above, the CPU 7 has specified which of the three despreading codes corresponding to the respective three areas at the maximum for the finger, which despreading code is to be used. In this case, the finger is directly designated from the searcher 3 to each of the fingers 41 to 4n. RAKE
The synthesizing unit 5 synthesizes the data extracted by the respective fingers, that is, performs a multipath component synthesizing process. (Although the content of the actual data is the same even in the case of multipass, by finally synthesizing, Even if waves of up to three areas are received simultaneously by handover, the areas are different but the contents of the received data are the same).

The Viterbi decoding unit 6 decodes the data in units of frames (10 msec) synthesized by the RAKE synthesizing unit 5 and notifies the CPU 7 as received data in units of units (several frames). The CPU 7 transfers the unit data to the voice CODEC (codec) or the ISDN terminal.

An embodiment of the present invention will be described below with reference to FIG. The mobile communication device receives the perch channel transmitted by the base station, and enters a call by performing communication on a call channel having some offset with respect to the perch channel, thereby transiting to a call state. The spreading code differs between the perch channel and the speech channel. In addition, the mobile communication device monitors the multipath (time delay) of the perch channel serving as a reference during a call, and combines these multipath components by performing reception processing using a plurality of receivers. As a result, the reception quality is improved. In addition, by periodically assigning the timing at which the receiver receives multipath components, the receiver can cope with multipath that changes due to movement or interference.

Conventionally, as described above, there is a case where the pulse of the reception timing at the finger and the code used for despreading do not coincide with each other for about 10 msec at the moment when the timing is assigned. There was a momentary interruption. On the other hand, in the present invention, the timing (finger) assignment is improved. That is, according to the present invention, the path information (valid / invalid information, branch number) for finger assignment is notified to the fingers 41 to 4n and the RAKE combining unit 5 without passing through the CPU 7.

FIG. 2 is a flowchart showing the processing.
The points different from the conventional processing flow of FIG. 4 will be described.
A serial line for transferring finger assignment information is connected between the searcher 3 and each of the fingers 41 to 4n and the RAKE combining unit 5, and the delay amount between the multipath component and the perch channel is determined by the timing control unit 2 as before. The path reception valid / invalid information is directly transmitted to each finger, and the branch number is directly transmitted to each finger and the RAKE combining unit without passing through the CPU 7 (step S2).

Each finger can perform the despreading process with the code corresponding to the branch number in synchronization with the new clock pulse after updating the timing assignment.
No mismatch occurs (step S4). The RAKE combining unit 5 can also combine received data from each finger without generating a mismatch state, so that the instantaneous interruption operation is improved (step S5).

Since the path validity / invalidity information and the branch number from the searcher 3 are notified without synchronizing with the frame pulse from the timing control unit 2, the finger or RAKE is notified.
It is needless to say that the synthesizing unit needs to take into consideration that the synthesis is performed from the next frame pulse received serially.

In the above embodiment, the searcher 3 notifies the timing controller 2 of the delay amount of the multipath component with respect to the timing of the perch channel, and the timing controller 2 sends to each of the fingers 41 to 4n a clock in consideration of this delay amount. Although the pulse is notified, the searcher 3 can also monitor the reference timing of the perch channel, and can directly notify the fingers 41 to 4n of the reception clock pulse at the time of timing assignment.

[0028]

According to the first effect of the present invention, since no instantaneous interruption occurs at the time of finger assignment, unlimited (videophone) images are momentarily stopped at the time of branch addition / deletion at the time of handover or at the time of multipath reception. That will be improved. The second effect is that the finger assignment is performed without passing through the CPU, so that the CPU does not need to perform processing periodically, and the operation rate of the CPU is reduced, and the effect of battery saving is further improved. .

[Brief description of the drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a flowchart showing the operation of the embodiment of the present invention.

FIG. 3 is a block diagram showing a conventional technique.

FIG. 4 is a flowchart showing the operation of the block diagram of FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 RF part 2 Timing control part 3 Searcher 41-4n Finger 5 RAKE synthesis part 6 Viterbi decoding part 7 CPU

Claims (7)

[Claims] 1. A mobile communication system in which path information of a plurality of paths in a multipath propagation signal is acquired by a searcher, and fingers are assigned to demodulate received signals of the plurality of paths according to the path information. A finger assignment method in a machine, wherein the path information is directly supplied from the searcher to each of the fingers. 2. The finger assignment method according to claim 1, wherein the path information includes validity / invalidity information indicating validity of the path and a service area number of the mobile communication device. 3. A synthesizing means for synthesizing each demodulated output from said finger, wherein said path information is also supplied directly from said searcher to said synthesizing means. The described finger assignment scheme. 4. The finger assignment method according to claim 1, wherein said searcher periodically acquires said path information. 5. A mobile communication device using the finger assignment method according to claim 1. 6. The mobile communication device according to claim 5, wherein the mobile communication device is a CDMA mobile communication device. 7. The mobile communication device according to claim 6, wherein said combining means is a RAKE combining circuit.