JPH1169405A - Hand-off system and hand-off device for ds-cdma system mobile station - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform soft hand-off and to evade complete disconnection from a moving origin base station by performing site diversity reception between the respective base stations of a moving origin and a moving destination until all branches are connected to the moving destination base station. SOLUTION: At the time of approaching a base station BS2 while performing the 2 branch diversity reception of the base station BS1 before hand-off, when hand-off request signals are outputted from the base station BS1 to a mobile station, after long code timing detection and fixation, the delay profile timing of a base station BS2 control channel in the branch 2 is detected. That is, a matched filter 17 for the control channel computes the correlation of base station BS2 demodulation signals from a demodulation part 12 and a spreading code for the control channel from a code generation part 115 for the control channel and outputs it to a selector 19, the delay profile timing is detected based on it and the 2 branch diversity reception of a base station BS1 communication channel and spreading code transmission timing adjustment in a base station BS2 branch 2 are performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DS-CDMA (Direct Sequence) using a long code.
e-Code Division Multiple
Access: Direct spreading code division multiple access) This relates to a base station switching (handoff) function of a mobile station.

[0002]

2. Description of the Related Art In a DS-CDMA system using a long code, a code obtained by multiplying a code (long code) circulating in a cycle of one frame or more and a code (short code) circulating in a symbol cycle is used as a spreading code. By using this method, it is possible to perform RAKE combining even on a long delay signal.

In mobile communication, it is necessary to perform handoff of a mobile station when moving between service areas of different base stations. It is DS-CDM using long code
The same applies to the A method.

FIG. 7 shows a conventional DS using a long code.
2 shows an example of a circuit configuration of a handoff device of a CDMA mobile station. FIG. 7 shows a case where the number of branches of space diversity used for reducing the effect of fading is two. In FIG. 7, reference numeral 411 denotes branch 1
And 412, a demodulation unit for demodulating the received signal of the branch 2. A control unit 413 performs handoff control.

[0005] A communication channel matched 414 is provided on the output side of the demodulation unit 411 and calculates the correlation between the communication channel of the branch 1 and the spread code for the communication channel (code obtained by multiplying the long code and the short code of the communication channel). Filter. Reference numeral 415 is provided on the output side of the demodulation unit 411, and the control channel of the branch 1 and the control channel spreading code (the long code and the control channel have the same code as the long code related to the communication channel spreading code, but have different phases depending on the case) This is a matched filter for a control channel that calculates a correlation with a code obtained by multiplying the short code by a short code.

Reference numeral 417 denotes a communication channel matched filter which is provided on the output side of the demodulation unit 412 and calculates the correlation between the communication channel of the branch 2 and the communication channel spread code. Reference numeral 416 denotes a control channel matched filter which is provided on the output side of the demodulation unit 412 and calculates the correlation between the control channel of the branch 2 and the control channel spreading code.

A delay profile timing detector 418 is provided on the output side of the matched filter 414 for the communication channel of the branch 1 and detects a delay profile timing. 419 is a matched filter 41 for the control channel.
5 is a delay profile timing detection unit for detecting a delay profile timing. 4
A selector 24 selects one of the outputs of the delay profile timing detectors 418 and 419 based on the output of the controller 413.

Reference numeral 423 is provided on the output side of the matched filter 417 for the communication channel of the branch 2, and a delay profile timing detector 422 for detecting the delay profile timing is provided with a matched filter 41 for the control channel.
6 is a delay profile timing detection unit that is provided on the output side and detects a delay profile timing. 4
Reference numeral 25 denotes a selector for selecting one of the outputs of the delay profile timing detectors 423 and 422 based on the output of the controller 413.

Reference numeral 426 denotes a communication channel code generation unit which is provided on the output side of the selector 424 and outputs a spread code for the communication channel of the branch 1. 420 is provided on the output side of the delay profile timing detection unit 419. This is a control channel code generation unit that outputs a spreading code for the control channel of branch 1.

Reference numeral 427 denotes a communication channel code generation unit which is provided on the output side of the selector 425 and outputs a spread code for the communication channel of the branch 2, and 421 is provided on the output side of the delay profile timing detection unit 422. This is a control channel code generation unit that outputs a spreading code for the control channel of branch 2.

Reference numeral 428 denotes a communication channel code generator 4 of the branch 1 in response to a handoff control signal from the controller 13.
26, or the communication channel code generation unit 42 of the branch 2
7 is a switch for freely switching the input of the spread code output from 7 to the matched filter 414 for the communication channel of the branch 1 or the matched filter 417 for the communication channel of the branch 2.

FIGS. 8 and 9 are connection diagrams of a conventional hand-off circuit according to the configuration example of FIG. Hereinafter, the operation of the conventional handoff device will be described with reference to these drawings. Now, it is assumed that a signal from the base station BS1 is receiving two-branch diversity. At this time, the respective units are connected as shown in "(a) Before handoff" in FIG. Specifically, demodulation section 411 demodulates the signal of branch 1 and demodulation section 412 demodulates the received signal of branch 2, and demodulation section 411 converts the demodulated signal to matched filter 414 for communication channel and matched filter 415 for control channel. The demodulation unit 412 outputs the demodulated signal to the control channel matched filter 416 and the communication channel matched filter 417, respectively.

The matched filter for communication channel 414 receives the demodulated signal input from the demodulator 411 and the switch 42
8 and calculates a correlation with the communication channel spreading code input from 8 and outputs it to the delay profile timing detection unit 418 and a communication channel signal processing unit (not shown). Control channel matched filter 415 calculates a correlation between the demodulated signal input from demodulation section 411 and the control channel spreading code input from control channel code generation section 420, and outputs the result to delay profile timing detection section 419.

A delay profile timing detector 419
Detects the delay profile timing based on the correlation value input from the matched filter for control channel 415, and the first peak position in the delay profile always appears at the same position for the control channel code generation unit 420. Thus, the spread code transmission timing is adjusted, and the synchronization of the branch 1 is maintained.

A communication channel matched filter 417,
The control channel matched filter 416, the delay profile timing detection units 422 and 423, and the control channel code generation unit 421 also perform the same operation as the branch 1 on the branch 2.

Before the handoff, two-branch diversity reception for the base station BS1 is performed. At this time, in each branch, the control channel and the communication channel have the same frequency and the same propagation path. Therefore, if the delay profile timing of the control channel is obtained, it is not necessary to detect the delay profile timing of the communication channel. Therefore, in branch 1, the control unit 413 selects the timing output from the delay profile timing detection unit 419 on the control channel side by the selector 424, and thereby adjusts the spread code transmission timing of the communication channel code generation unit 426. . Similarly, in branch 2,
Based on the timing from the delay profile timing detection unit 422 on the control channel side selected by the selector 425, the spread code transmission timing of the communication channel code generation unit 427 is adjusted.

At this time, the control unit 413 operates the switch 428 so as to have the switch configuration shown in the flow before handoff in FIG. As a result, the communication channel spreading code output from the communication channel code generation section 426 on the branch 1 side matches the communication channel matched filter 414.
And 417.

By this series of operations, the mobile station is connected to the base station B.
It is assumed that the mobile terminal approaches the base station BS2 while performing 2-branch diversity reception of S1. Here, when a handoff request signal is output from the base station BS1 to the mobile station, the mobile station starts a handoff operation to the base station BS2.

At this time, in the asynchronous system between base stations,
Since the long code timing obtained from the base station BS2 is different from that of the base station BS1 and the long code timing is different between the control channel and the communication channel, it is necessary to detect the delay profile timing also for the communication channel.

Next, the branches 1 and 2 simultaneously detect the delay profile timing of the base station BS2.
At this time, the respective units are connected as shown in "(a) Detection of adjacent channel timing" in FIG. In particular,
In the branch 1, the control unit 413 selects the timing output from the delay profile timing detection unit 418 on the communication channel side by the selector 424, and thereby adjusts the spread code transmission timing of the communication channel code generation unit 426.

Similarly, in the branch 2, the spread code transmission timing of the communication channel code generation section 427 is adjusted based on the timing from the communication channel side delay profile timing detection section 423 selected by the selector 425.

At this time, the control unit 413 operates the switch 428 so as to obtain the switch configuration shown in the flow during handoff in FIG. Thus, the communication channel spread code output from communication channel code generation section 426 is output to communication channel matched filter 414, and the communication channel spread code output from communication channel code generation section 427 is output to communication channel matched filter. 417 respectively.

With this series of operations, even if the delay profile timing in the control channel and the delay profile timing in the communication channel have different long code timings, the matched filter for the communication channel has the correct spreading code for the communication channel. It is possible to supply

When both branches are connected to the base station BS2, the respective units are connected as shown in "(c) Handoff end" in FIG.

[0025]

However, in the above-mentioned conventional circuit, the control channel and the communication channel of all branches simultaneously detect the delay profile timing of the destination base station at the time of handoff between base stations. Therefore, at the time of handoff, there is a problem that a hard handoff is performed in which the connection with the source base station is instantaneously and completely disconnected. Also, since the delay profile timing detector is provided for each matched filter, the delay profile timing detector needs a memory for storing the correlation value for one symbol.
There is also a problem that the circuit scale and power consumption increase. If only the delay profile timing detection unit is converted to a gate, the number of gates for two branches is 24000 gates.
In terms of power consumption, when the operation clock is 10 MHz, the power consumption is about 700 mW, which is a value that cannot be ignored for low power consumption design.

The present invention has been made to solve the above-mentioned conventional problems, and enables connection with a destination base station without completely disconnecting from a source base station at the time of handoff. It is another object of the present invention to provide a DS-CDMA mobile station handoff system and an apparatus thereof that can reduce an increase in circuit scale and power consumption by a memory.

[0027]

A DS-C according to the present invention
In a handoff method of a DMA mobile station, when a mobile station moves through a service area of a plurality of base stations, the plurality of base stations transmit the same information spread by different long code spreading codes at substantially the same time. When the mobile station realizes the soft handoff function of seamlessly shifting communication from the service area of one base station to the service area of the other base station while simultaneously receiving the plurality of transmission signals on a plurality of branches, Detection of the delay profile timing of the control channel and the communication channel of the destination base station is performed in only one arbitrary branch among the plurality of branches, and after the above-mentioned branch is connected to the destination base station, the other branches are similarly sequentially transmitted. Detection and connection of the delay profile timing of the control channel and communication channel of the destination base station. Until all branches are connected to the destination base station, the site diversity reception that combines while receiving the same information between the source base station and the destination base station is performed. It was done.

Further, a hand-off device for a DS-CDMA mobile station according to the present invention multiplies a first code and a second demodulator for demodulating a received radio signal into a baseband, and multiplies a long code by a short code of a communication channel. First and second communication channel code generators for generating a communication channel spreading code which is a converted code, a baseband signal input from the first demodulator, and the first or second communication channel code A first communication channel matched filter that calculates a correlation with a communication channel spreading code input from the generation unit and outputs a result; a baseband signal input from the second demodulation unit and the first or second A second communication channel matched filter for calculating the correlation with the communication channel spreading code input from the second communication channel code generation unit and outputting the result , A first and second control channel code generation unit for generating a control channel spreading code which is a code obtained by multiplying a long code having the same code as the long code but different phases in some cases by a short code of the control channel. And a first control for calculating a correlation between a baseband signal input from the first demodulation unit and a control channel spreading code input from the first control channel code generation unit, and outputting a result. A channel matched filter, and a second unit for calculating a correlation between a baseband signal input from the second demodulation unit and a control channel spreading code input from the second control channel code generation unit, and outputting a result. 2 matched filters for the control channel and the matched filter for the first communication channel or the matched filter for the first control channel. A first delay profile timing detection unit for detecting a delay profile timing from the input correlation result, and a delay profile timing from a correlation result input from the second communication channel matched filter or the second control channel matched filter. , A first selector for switching the outputs of the first communication channel matched filter and the first control channel matched filter, and the second communication channel matched filter. And a second selector for switching the output of the matched filter for the second control channel, and the output of the code generator for the first communication channel and the code generator for the second communication channel to the first and second communications. A changeover switch that can be freely connected to the matched filter for channels,
And a control section for controlling the first and second selectors and the changeover switch.

Further, the DS-CDMA according to the present invention
In a mobile station handoff device, the matched filter is provided in an ADF (Analog Digital F).
ilter).

According to such a configuration, it is possible to connect to the destination base station without completely disconnecting from the source base station at the time of handoff, and to reduce the circuit scale and power consumption by the memory. The increase can be reduced.

[0031]

Embodiments of the present invention will be described below with reference to the drawings. In the embodiment described below, the number of branches of space diversity used for reducing the effect of fading is set to 2 as described in the related art.

Embodiment 1 FIG. 1 is a block diagram showing an example of a handoff circuit configuration of a DS-CDMA mobile station using a long code according to the first embodiment. In FIG. 1, reference numeral 11 denotes a demodulation unit that demodulates the reception signal of the branch 1, and reference numeral 12 denotes a demodulation unit that demodulates the reception signal of the branch 2. Reference numeral 13 denotes a control unit that performs handoff control.

Numeral 14 denotes a matched filter for the communication channel which is provided on the output side of the demodulation unit 11 and calculates the correlation between the communication channel of the branch 1 and the spread code for the communication channel. 15 is provided on the output side of the demodulation unit 11, and the branch 1
And a control channel matched filter for calculating the correlation between the control channel and the control channel spreading code.

Reference numeral 16 denotes a matched filter for the communication channel which is provided on the output side of the demodulation unit 12 and calculates the correlation between the communication channel of the branch 2 and the spread code for the communication channel. 17 is provided on the output side of the demodulation unit 12, and the branch 2
And a control channel matched filter for calculating the correlation between the control channel and the control channel spreading code.

A selector 18 selects one of the correlation value input from the communication channel matched filter 14 of the branch 1 and the control channel matched filter 15. Reference numeral 19 denotes a selector for selecting one of the correlation value input from the communication channel matched filter 16 of the branch 2 and the control channel matched filter 17.

Reference numeral 110 denotes a delay profile timing detection unit that detects a delay profile timing based on the correlation value selected by the selector 18 of the branch 1 and holds the synchronization of the branch 1. Reference numeral 111 denotes a communication channel code generation unit that outputs a spread code for the communication channel of the branch 1, and reference numeral 112 denotes a control channel code generation unit that outputs a spread code for the control channel of the branch 1.

Reference numeral 113 denotes a delay profile timing detection unit which detects a delay profile timing based on the correlation value selected by the selector 19 of the branch 2 and holds the synchronization of the branch 2. Reference numeral 114 denotes a communication channel code generation unit that outputs a spread code for the communication channel of the branch 2, and 115 denotes a control channel code generation unit that outputs a spread code for the control channel of the branch 2.

Reference numeral 116 denotes a communication channel code generation unit 11 of the branch 1 in response to a handoff control signal from the control unit 13.
1 or a switch for switching the input of the spread code output from the communication channel code generation unit 114 of the branch 2 to the matched filter 14 for the communication channel of the branch 1 or the matched filter 16 for the communication channel of the branch 2.

The operation of the first embodiment will be described below with reference to FIGS. Here, FIGS.
FIG. 2 is a connection diagram of a device for showing a DS-CDMA mobile station handoff system using a long code according to Embodiment 1 of the present invention. FIG. 2 shows a state before handoff and detection of a branch 2 adjacent control channel. FIG. 3 is a connection relation diagram showing a branch 2 adjacent communication channel detection state and a branch 2 constant connection state, and FIG. 4 is a connection diagram showing a branch 1 adjacent control channel detection state and a branch 1 adjacent communication channel detection state. FIG. 5 is a connection diagram showing a handoff end state. Further, in these drawings, the same reference numerals as those in FIG. 1 indicate the same or equivalent parts as those in FIG.

First, the flow of control from the start of handoff to the reception of site diversity will be described with reference to FIGS. 1, 2 and 3. Now, it is assumed that a signal from the base station BS1 is receiving two-branch diversity. At this time, the respective units are connected as indicated by "(A) Before handoff" in FIG. Specifically, the demodulation unit 11 demodulates the branch 1 reception signal, and the demodulation unit 12 demodulates the branch 2 reception signal. Then, the demodulation unit 11 outputs the demodulated signal to the communication channel matched filter 14 and the control channel matched filter 15, and the demodulation unit 12 outputs the demodulated signal to the communication channel matched filter 16 and the control channel matched filter 17, respectively. .

The matched filter 14 for the communication channel of the branch 1 calculates the correlation between the demodulated signal input from the demodulation unit 11 and the spread code for the communication channel input from the switch 116, and selects the selector 18 and the communication channel signal processing unit. Output to The control channel matched filter 15 calculates a correlation between the demodulated signal input from the demodulation unit 11 and the control channel spread code input from the control channel code generation unit 112, and outputs the correlation to the selector 18 and the control channel signal processing unit. Output.

The matched filter 16 for the communication channel of the branch 2 calculates the correlation between the demodulated signal input from the demodulation unit 12 and the spread code for the communication channel input from the switch 116, and selects the selector 19 and the signal processing unit for the communication channel. Output to The control channel matched filter 17 calculates the correlation between the demodulated signal input from the demodulation unit 12 and the control channel spread code input from the control channel code generation unit 115, and outputs the result to the selector 19.

The operation up to the calculation of the correlation value is the same as in the prior art. As in the prior art, before the handoff, the base station BS1 performs 2-branch diversity reception, so there is no need to detect the delay profile timing of the communication channel. Therefore, the control unit 13 selects the correlation values output from the control channel matched filter 15 in the branch 1 and the correlation values output from the control channel matched filter 17 in the branch 2 to select the correlation values. Operate.

The delay profile timing detecting section 110 of the branch 1 detects the delay profile timing based on the correlation value of the control channel input from the selector 18, and sends it to the communication channel code generating section 111 and the control channel code generating section 112. On the other hand, the spread code transmission timing is adjusted. Similarly, the delay profile timing detection unit 113 of the branch 2 detects the delay profile timing based on the correlation value of the control channel input from the selector 19, and outputs the communication channel code generation unit 11
4 and the control channel code generating section 115 are adjusted for the spread code transmission timing.

Control channel code generator 1 of branch 1
12 supplies the control channel spreading code to the control channel matched filter 15. Similarly, the control channel code generation section 115 of the branch 2 supplies the control channel spread code to the control channel matched filter 17.

At this time, the control unit 13 performs the same operation as in the prior art.
The switch 116 is operated so that the switch configuration (the right column in FIG. 2A) shown in the flow before handoff in FIG. 2 is obtained. As a result, the communication channel spread code output from the communication channel code generation unit 111 of the branch 1 is supplied to the communication channel matched filters 14 and 16 of the branches 1 and 2.

When a mobile station performing this series of operations approaches the base station BS2 while performing 2-branch diversity reception of the base station BS1, a handoff request signal is output from the base station BS1 to the mobile station. If
The mobile station starts a handoff operation to the base station BS2.

In this case, after detecting and identifying the long code timing by an external circuit, the delay profile timing of the control channel of the base station BS2 in the branch 2 is detected. In this case, the respective units are connected as shown in "(B) Detection of adjacent control channel on branch 2" in FIG. Specifically, the matched filter for control channel 17 calculates a correlation between the demodulated signal of the base station BS2 input from the demodulation unit 12 and the spread code for control channel input from the code generation unit 115 for control channel, and selects the selector 19
Output to

At this time, the control unit 13 selects the correlation value from the control channel matched filter 17 by the selector 19 and supplies the correlation value to the delay profile timing detection unit 113. The delay profile timing detecting section 113 detects the delay profile timing based on the correlation value of the control channel input from the selector 19 and adjusts the spread code transmission timing to the control channel code generating section 115. The configuration of the switch 116 is the same as before the handoff as shown in FIG.

By this operation, it is possible to perform 2-branch diversity reception of the communication channel of the base station BS1, and at the same time, adjust the spread code transmission timing of the control channel in the branch 2 of the base station BS2.

Next, the delay profile timing of the communication channel of the base station BS2 in the branch 2 is detected. At this time, the respective units are connected as shown in "(C) Detection of adjacent communication channel on branch 2" in FIG. Specifically, the communication channel matched filter 16 calculates the correlation between the demodulated signal of the base station BS2 input from the demodulation unit 12 and the communication channel spread code input from the switch 116, and outputs the result to the selector 19. .

At this time, the control unit 13 selects a correlation value from the communication channel matched filter 16 by the selector 19 and supplies the correlation value to the delay profile timing detection unit 113. The delay profile timing detector 113 detects the delay profile timing based on the communication channel correlation value input from the selector 19 and adjusts the spread code transmission timing to the communication channel code generator 114.

The control unit 13 changes the configuration of the switch 116 as shown in the right column of FIG. As a result, the communication channel spread code output from the communication channel code generation section 111 of the branch 1 is supplied to the communication channel matched filter 14, and the communication channel spread code output from the communication channel code generation section 114 of the branch 2 is output. The spreading code is supplied to the communication channel matched filter 16.

At this time, the system dedicated to the communication channel of the branch 2 is separated from the communication channel of the base station BS1 in order to detect the delay profile timing of the communication channel of the base station BS2. By this operation, the base station BS1
At the same time as the single branch reception of
The transmission timing of the spread code of the communication channel of the base station BS2 in the branch 2 can be adjusted.

Next, site diversity reception is performed based on the delay profile timing of the control channel and communication channel of the base station BS2 in the branch 2 detected in the previous stage. In this case, “(C) branch 2 in FIG.
Each part is connected as shown by “always connected”. Specifically, the control unit 13 selects the correlation value output from the matched filter 17 for the control channel of the branch 2 by the selector 19, and
To supply.

Delay profile timing detection section 113
Detects the delay profile timing based on the correlation value of the control channel input from the selector 19 and adjusts the spread code transmission timing for the communication channel code generation unit 114 and the control channel code generation unit 115.
The configuration of the switch 116 is the same as that at the time of the single branch reception of the base station BS1 in the previous stage. Thereby, the base station B
It becomes possible to perform site diversity reception between S1 and the base station BS2.

Next, the flow of control from the reception of site diversity to the end of handoff will be described with reference to FIGS. 1, 4 and 5. First, after establishing the site diversity reception between the base stations BS1 and BS2, the delay profile timing of the control channel of the base station BS2 in the branch 1 is detected. In this case, “(E) branch 1 in FIG.
Each unit is connected as shown in “Adjacent control channel detection”. More specifically, the control channel matched filter 15
Calculates the correlation between the demodulated signal of the base station BS2 input from the demodulation unit 11 and the control channel spread code input from the control channel code generation unit 112,
Output to

The control section 13 is the same as the previous step, and the selectors 18 and 19 control the control channel matched filter 1.
Correlation values from 5 and 17 are selected and supplied to the delay profile timing detectors 110 and 113, respectively.
The delay profile timing detection unit 110 selects the selector 1
Based on the correlation value of the control channel input from step 8, the delay profile timing is detected, and the spread code transmission timing is adjusted for the control channel code generation unit 112. The configuration of the switch 116 is the same as that at the time of receiving site diversity at the previous stage (FIG. 3D).

By this operation, the base stations BS1 and B
At the same time as performing the site diversity reception of the communication channel in S2, it is possible to adjust the spread code transmission timing of the control channel of the base station BS2 in the branch 1.

Next, the delay profile timing of the communication channel of the base station BS2 in the branch 1 is detected. At this time, the respective units are connected as shown in "(F) Detection of adjacent communication channel on branch 1" in FIG. Specifically, the communication channel matched filter 14 calculates a correlation between the demodulated signal of the base station BS2 input from the demodulation unit 11 and the communication channel spreading code input from the switch 116, and outputs the correlation to the selector 18. .

At this time, the controller 13 selects the correlation value from the communication channel matched filter 14 by the selector 18 and supplies it to the delay profile timing detector 110. The delay profile timing detector 110 detects the delay profile timing based on the communication channel correlation value input from the selector 18 and adjusts the spread code transmission timing to the communication channel code generator 111. The configuration of the switch 116 is the same as that of the previous stage at the time of site diversity.

At this time, the system dedicated to the communication channel of the branch 1 is separated from the communication channel of the base station BS1 in order to detect the delay profile timing of the communication channel of the base station BS2. By this operation, the base station BS2
At the same time as performing the single-branch diversity reception in the branch 2, the transmission code spreading timing adjustment of the communication channel in the branch 1 of the base station BS2 can be performed.

Finally, two-branch diversity reception of the base station BS2 is performed based on the delay profile timing of the control channel and the communication channel of the base station BS2 in the branch 1 detected in the previous stage. At this time, the respective units are connected as shown by "(G) Handoff end" in FIG. Specifically, the control unit 13 operates the switch 116 so as to have the switch configuration shown in the right column of the flow of FIG. As a result, the communication channel spread code output from the communication channel code generation unit 114 of the branch 2 is supplied to the communication channel matched filters 14 and 16. With this operation, the base station BS2 can receive two branches of diversity, and the handoff ends.

Embodiment 2 Hereinafter, a second embodiment of the present invention will be described. The second embodiment is different from the first embodiment.
ADF (Analog D)
digital filter). FIG. 6 is a block diagram showing a configuration example of a handoff circuit of a DS-CDMA mobile station using a long code according to Embodiment 2.

In FIG. 6, reference numeral 31 denotes a demodulator for demodulating the received signal of the branch 1, and 32 denotes a demodulator for demodulating the received signal of the branch 2. A control unit 33 is provided between the branch 1 and the branch 2 and performs handoff control.

Reference numeral 34 denotes an ADF for a communication channel which is provided on the output side of the demodulation unit 31 and calculates a correlation between the communication channel of the branch 1 and the spread code for the communication channel. A control channel ADF 35 is provided on the output side of the demodulation unit 31 and calculates the correlation between the control channel of the branch 1 and the control channel spreading code.

A communication channel ADF 36 is provided on the output side of the demodulation unit 32 and calculates the correlation between the communication channel of the branch 2 and the communication channel spreading code. Reference numeral 37 denotes a control channel ADF that is provided on the output side of the demodulation unit 32 and calculates the correlation between the control channel of the branch 2 and the control channel spreading code.

38 is an ADF for the communication channel of branch 1
A selector 39 selects one of the correlation values input from the control channel ADF 35 and the control channel ADF 35. The selector 39 selects either the communication channel ADF 36 of the branch 2 or the correlation value input from the control channel ADF 37. It is a selector.

Reference numeral 310 denotes a delay profile timing detection unit for detecting the delay pro-filter timing based on the correlation value selected by the selector 38 of the branch 1 and holding the synchronization of the branch 1. Is a communication channel code generation unit that outputs the spread code of the communication channel. Reference numeral 312 denotes a control channel code generation unit that outputs a spread code for the control channel of the branch 1.

Reference numeral 313 denotes a delay profile timing detection unit for detecting the delay profile timing based on the correlation value selected by the selector 39 of the branch 2 and holding the synchronization of the branch 2. Reference numeral 314 denotes a communication channel for the communication channel of the branch 2. This is a communication channel code generation unit that outputs a spread code. Reference numeral 315 denotes a control channel code generation unit that outputs a spreading code for the control channel of branch 2.

Reference numeral 316 denotes a communication channel code generator 3 of the branch 1 in response to a handoff control signal from the controller 33.
11 or the code generator 31 for the communication channel of the branch 2
4 is a switch for switching the input of the spread code output from the ADF 34 for the communication channel ADF 34 of the branch 1 or the ADF 36 for the communication channel of the branch 2.

The configuration itself in the second embodiment is the same as the circuit shown in the first embodiment, but the matched filters for both channels in the first embodiment are ADFs 34, 35,
36 and 37 are different.

The ADF is considerably effective in circuit design because both the circuit area and the power consumption are reduced to about one-fourth as compared with the digital matched filter (refer to “Matched filter LSI for wideband DS-CDMA”). "
Sawabashi, Adachi, Kotobuki, Zhou et al., The Institute of Electronics, Information and Communication Engineers, Radio Communication Systems Study Group, RCS96-01).

[0074]

As described above, the DS-CDMA of the present invention is used.
According to the mobile station handoff method and apparatus, at the time of handoff, it is possible to detect the delay profile timing of the destination base station and connect at the same time as being connected to the source base station, so that soft handoff is performed. And complete disconnection from the source base station can be avoided. Further, by using the delay profile timing detection unit by switching it for each control channel and communication channel, the number of memories is reduced to one, so that the circuit scale and power consumption by the memory can be reduced to half of the conventional one. . Further, by replacing the matched filter with the ADF, it is possible to further reduce the circuit scale and power consumption, and the effect is remarkable.

[Brief description of the drawings]

FIG. 1 is a diagram showing a D using a long code according to the first embodiment.
FIG. 2 is a block diagram illustrating an example of a handoff circuit configuration of an S-CDMA mobile station.

FIG. 2 is a connection diagram showing a state before handoff and a branch 2 adjacent control channel detection state.

FIG. 3 is a connection relation diagram showing a branch 2 adjacent communication channel detection state and a branch 2 constant connection state.

FIG. 4 is a connection diagram showing a branch 1 adjacent control channel detection state and a branch 1 adjacent communication channel detection state.

FIG. 5 is a connection diagram showing a handoff end state.

FIG. 6 is a diagram illustrating D using a long code according to the second embodiment.
FIG. 2 is a block diagram illustrating an example of a handoff circuit configuration of an S-CDMA mobile station.

FIG. 7 is a block diagram illustrating a configuration example of a handoff circuit of a conventional DS-CDMA mobile station.

FIG. 8 is a connection relation diagram showing a state before handoff and an adjacent channel timing detection state in the related art.

FIG. 9 is a connection diagram in a handoff end state in the related art.

[Explanation of symbols]

11, 12, 31, 32 Demodulation unit 13, 33 Control unit 14, 16 Matched filter for communication channel 15, 17 Matched filter for control channel 18, 19, 38, 39 Selector 110, 113, 310, 313 Delay profile timing detection unit 111, 114, 311 and 314 Communication channel code generators 112, 115, 312 and 315 Control channel code generators 116 and 316 switches

Claims (3)

[Claims] When a mobile station moves in a service area of a plurality of base stations, the plurality of base stations transmit the same information spread with spreading codes of different long codes from each other at substantially the same time. When realizing a soft handoff function that seamlessly shifts communication from the service area of one base station to the service area of the other base station while simultaneously receiving the plurality of transmission signals on the plurality of branches, The delay profile timing of the control channel and the communication channel of the destination base station is detected only in one arbitrary branch of the destination base station, and after the above branch is connected to the destination base station, the other branches are similarly sequentially moved to the destination base station. Control channel and communication channel delay profile timing detection and connection operation of the base station. Until a branch is connected to a destination base station, a site diversity reception for combining data while receiving the same information between the source base station and the destination base station is performed. -CDMA mobile station handoff scheme. 2. A first and second demodulator for demodulating a received radio signal to a baseband, and a first and a second demodulator for generating a communication channel spreading code which is a code obtained by multiplying a long code by a communication channel short code. A second communication channel code generation unit, and a correlation between a baseband signal input from the first demodulation unit and a communication channel spreading code input from the first or second communication channel code generation unit. A first communication channel matched filter that outputs an operation and a result, a baseband signal input from the second demodulation unit, and a communication channel input from the first or second communication channel code generation unit. A second communication channel matched filter for calculating the correlation with the spreading code and outputting the result; and the long code and the code are the same, but in some cases the phase is A first and a second control channel code generator for generating a control channel spreading code which is a code obtained by multiplying a long code by a control channel short code, and a baseband signal input from the first demodulator A first control channel matched filter for calculating the correlation between the control code and the control channel spreading code input from the first control channel code generation unit and outputting the result; and inputting from the second demodulation unit. A second control channel matched filter for calculating a correlation between a baseband signal and a control channel spreading code input from the second control channel code generation unit and outputting a result, and for the first communication channel. Detecting a delay profile timing from a correlation result input from the matched filter or the matched filter for the first control channel; A second delay profile timing detector, a second delay profile timing detector that detects a delay profile timing from a correlation result input from the second communication channel matched filter or the second control channel matched filter, A first selector for switching the outputs of the first communication channel matched filter and the first control channel matched filter; and a switching of the outputs of the second communication channel matched filter and the second control channel matched filter. A second selector; and a changeover switch capable of freely switching and connecting the outputs of the first communication channel code generation unit and the second communication channel code generation unit to the first and second communication channel matched filters. Controlling the first and second selectors and the changeover switch Comprising a control unit DS-CDMA system handoff device of a mobile station. 3. The DS-CDMA mobile station handoff apparatus according to claim 2, wherein said matched filter is replaced with an analog digital filter.
Handoff device for CDMA mobile station.