JP2003273776A - Radio communication equipment and cell search method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accelerate searching of another cell. <P>SOLUTION: A self cell timing deletion part 119 takes out the timing of the path of a self cell from a delay profile outputted from a memory 116 for a communication channel, that is the timing of the path of a signal with which its own station communicates with a communication opposite party, and deletes a path existing at the timing of the path of its own cell from the delay profile outputted from a memory for cell search 110. To put it more concretely, the deletion part 119 sets a correlation value at the timing of the path of self cell to be '0' from the delay profile outputted from the memory 110. A first step processing part 111 detects the next candidate timing of another cell from a correlating result outputted from the deletion part 119. In this case a next candidate timing shows the timing of the path of a signal from another cell included in the delay profile. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless communication device and a cell search method, and more particularly to a wireless communication device and a cell search method suitable for use in a CDMA communication system.

[0002]

2. Description of the Related Art Conventionally, in cellular communication, a terminal must search for all possible codes for identifying a base station, which increases the hardware scale for cell search and increases the cell size. There was a problem that the search took time.

Therefore, in W-CDMA, a two-step or three-step search method has been proposed in order to shorten the time required for cell search. Hereinafter, a wireless communication system using the 3-step cell search will be described.

FIG. 11 is a diagram showing an example of a conventional wireless communication system. In FIG. 11, the mobile station 11 communicates with any one of the base station 12, the base station 13, and the base station 14. The base station 12 communicates with mobile stations within the range of the cell 22. Similarly, the base station 13 communicates with mobile stations within the range of the cell 23. The base station 14 then communicates with mobile stations within the range of the cell 24.

In FIG. 11, when the mobile station 11 whose position is registered in the base station 12 moves and hands over to another cell, adjacent cells other than the base station 12 (other cells, base station 13, base station 14). Cell-specific code (scrambling code), cell frame timing, and other additional information are reported to the base station 12. This is called another cell search. Here, the other cell indicates a communicable range with a base station apparatus to which the own station does not belong.

A radio receiving apparatus for performing another cell search will be described below. FIG. 12 is a block diagram showing a configuration of a conventional wireless reception device. In FIG. 12, the antenna 3
The radio signal received from 1 is subjected to frequency conversion from the carrier frequency to the baseband frequency in the reception RF unit 32, and is received as an A / D conversion unit 33 and an A / D conversion unit 34.
Is output to. Then, of the signals converted to the baseband frequency, the in-phase component (I-ch) is the A / D conversion unit 3
3 and the orthogonal component (Q-ch) is output to the A / D conversion unit 3
4 is output.

The A / D converter 33 converts the signal of the in-phase component from analog to digital. In addition, the A / D conversion unit 34
The signal of the quadrature component is converted from analog to digital. The wireless reception device 30 uses the received signal converted into a digital signal to identify the frame timing of another cell and the scrambling code unique to the cell.

First, the timing control unit 35 sets the timing for receiving the signal of its own cell in the code control unit 36, and receives the system-specific code used in the first stage of the three-stage cell search method and the signal of its own cell. The operation is instructed to the code generation unit 37 in accordance with the timing. here,
The own cell indicates a range in which communication is possible with the base station device to which the own cell belongs.

The system-specific code generated by the code generation unit 37 is set in the matched filter unit (MF) 38. The matched filter unit 38 performs a correlation calculation between the code unique to this system and the output signals of the A / D conversion unit 33 and the A / D conversion unit 34. The switch circuit 39 switches the output destination of the correlation result based on the determination result of the cell control mode or the communication channel mode in the code control unit 36.

When the operation of the radio receiving apparatus is in the cell search mode, the switch circuit 39 outputs the correlation result to the cell search memory 40. Then, the correlation result is stored in the cell search memory 40. Then, the first stage processing unit 4
1 detects the next candidate timing of another cell from the correlation result output from the cell search memory 40. Here, the next candidate timing indicates the timing of a path of a signal from another cell included in the delay profile.

The timing control unit 35 starts from the next candidate timing of another cell and the second stage processing unit 42 and the code control unit 36.
Output the code timing to. Here, the code timing indicates the timing of the path of the delay profile.

The second stage processing section 42 includes an A / D conversion section 33.
The frame timing and the code group of the scrambling code are identified from the output signal of the A / D converter 34 and the code timing output from the timing controller 35. Then, this frame timing is output to the code control unit 36 via the timing control unit 35.

The code control unit 36 includes a third stage processing unit 43.
The code generation unit 37 is instructed on the code used in step S1 and the code timing. The code generation unit 37 creates a code to be used in the third stage processing unit 43, and the code control unit 3
It outputs to the 3rd step process part 43 at the code timing which 6 instruct | indicates.

The third-stage processing section 43 includes an A / D conversion section 33.
Also, the correlation calculation between the output signal of the A / D converter 34 and the code generated by the code generator 37 is performed, and the code having the largest correlation value is identified as the scrambling code of another cell.

The own cell determination unit 44 is used for the scrambling code identified by the third stage processing unit 43 and the signals received by the output signals of the A / D conversion unit 33 and A / D conversion unit 34. The code of the own cell is compared, and the comparison result is output to the other cell detection number determination unit 45.

When the scrambling code identified in the third stage processing unit 43 is the same as the code of the own cell used for the received signal, the other cell detection number determination unit 4
5 indicates that the other cells are not detected and the number of detected other cells is not counted, and the timing detected by the first stage processing unit 41 is the timing of the path of the own cell.
Output to 1.

When the operation of the radio receiver is in the communication channel mode, the switch circuit 39 outputs the correlation result to the communication channel memory 46.

On the other hand, the receiver 47 performs soft decision processing on the output signals of the A / D converter 33 and A / D converter 34 at the timing indicated by the timing controller 35 for the code output from the code generator 37. And the soft decision result is demodulated by the demodulation unit 48.
Output to. The demodulation unit 48 performs hard decision processing from the soft decision result and demodulates the received data.

The radio receiving apparatus 30 repeats the processing from the first stage processing section 41 to the own cell determining section 44 until it reports all the other cell frame timings and scrambling codes designated by the base station. The operation of the wireless reception device 30 will be described below. FIG. 13 is a flowchart showing an example of the operation of the conventional wireless reception device.

In FIG. 13, step (hereinafter "ST")
51), the first stage processing unit 41 detects the next candidate timing of another cell from the correlation result output from the cell search memory 40. In ST52, the second
In the stage processing unit 42, the A / D conversion unit 33 and the A / D
The frame timing and the code group of the scrambling code are identified from the output signal of the conversion unit 34 and the code timing output from the timing control unit 35. In ST53, in the third stage processing unit 43, A /
The correlation calculation between the output signals of the D conversion unit 33 and the A / D conversion unit 34 and the code generated by the code generation unit 37 is performed, and the scrambling code of another cell is identified.

In ST54, the other cell detection number determination unit 45
Determines whether the identified scrambling code is the same as the code of the own cell used for the received signal. If the identified scrambling code is not the same as the code of the own cell used for the received signal, S
Returning to T51, the identified scrambling code is
When the code of the own cell used for the received signal is the same, the process proceeds to ST55.

In ST55, the other cell detection number determination section 45 determines whether or not all the other cell frame timings and scrambling codes designated by the base station have been reported. If the base station does not report the designated number of other cell frame timings and scrambling codes, the process returns to ST51 and reports the designated number of other cell frame timings and scrambling codes from the base station. If so, the process ends.

As described above, in the first stage processing section 41, the timing detected in the first stage is invalidated and the timing shown in FIG.
As shown in the processing flow chart shown in FIG. 3, the same processing is repeated from the first stage processing unit 41 to the own cell determination unit 44,
Further, the other cell detection number determination unit 45 repeats the processing from the first stage processing unit 41 to the own cell determination unit 44 until all the other cell frame timings and scrambling codes designated by the base station are reported.

[0024]

However, in the conventional apparatus, when performing the other cell search, all the paths obtained as a result of the correlation calculation of the code common to all cells and the received signal are targeted for the other cell search. Since the processing is performed, there is a problem that the other cell search time increases.

FIG. 14 is a diagram showing an example of the delay profile in the first stage of cell search. In FIG. 14, the vertical axis represents the reception level and the horizontal axis represents time. W indicates the range of the window width to be processed by the delay profile.

The paths 61, 62 and 63 are the base station 12
This is the path of the signal transmitted from. Also, the path 71 is
The path of the signal transmitted from the base station 13
Is a path of a signal transmitted from the base station 14. In the conventional wireless reception device, all of these paths are subjected to the processing of other cell search.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a radio communication apparatus and a cell search method capable of performing another cell search at high speed.

[0028]

A radio communication apparatus of the present invention comprises a delay profile creating means for creating a cell search delay profile which is a correlation between a synchronization code and a received signal, and a local station based on the cell search delay profile. And a cell search means for performing a cell search from the delay profile for cell search from which the path has been removed by the deleting means.

In the radio communication apparatus of the present invention, the delay profile creating means has a structure for creating a cell search delay profile which is a correlation between a synchronization code commonly used in a plurality of cells and a received signal.

In the radio communication apparatus of the present invention, the delay profile creating means has a structure for creating a cell search delay profile which is a correlation between a synchronization code and a received signal which is different for each cell.

According to these configurations, in the other cell search for searching for a candidate for a communication partner, the local station is selected from the delay profile indicating the correlation between the midamble code of the signal used when the local station communicates with the communication partner and the received signal. By selecting the path of the signal transmitted from the communication partner, removing this path from the delay profile for cell search and performing another cell search, the path of the own cell can be excluded from other cell search targets, Other cell search can be performed at high speed.

In the wireless communication apparatus of the present invention, the delay profile creating means creates an own cell delay profile which is a correlation between the received signal and the midamble code used for the signal of communication between the own station and the communication partner, and the deleting means. Adopts a configuration in which the signal path of the communication between the own station and the communication partner is removed from the cell search delay profile using the own cell delay profile.

In the wireless communication apparatus of the present invention, the deleting means adopts a structure for deleting the path at the timing when the signal path of the communication between the own station and the communication partner exists from the delay profile for cell search.

According to these configurations, in the other cell search for searching for a candidate for a communication partner, the local station is selected from the delay profile showing the correlation between the received signal and the midamble code of the signal used when the local station communicates with the communication partner. By selecting the path of the signal transmitted from the communication partner, removing this path from the delay profile for cell search and performing another cell search, the path of the own cell can be excluded from other cell search targets, Other cell search can be performed at high speed.

In the radio communication apparatus of the present invention, the deleting means has a structure in which the own cell delay profile is subtracted from the cell search delay profile for each path to delete the signal path of the communication between the own station and the communication partner. .

According to this structure, the delay profile of the signal of the own cell is subtracted from the delay profile for cell search on a path-by-path basis to delete the path of the signal of the communication between the own station and the communication partner. It is possible to leave the path having the same timing as that of the other cell in the delay profile, and it is possible to detect the frame timing and the scrambling code of the other cell even at the timing of the other cell at the same timing as the own cell timing.

In the wireless communication apparatus of the present invention, the deleting means selects the timing of the path of the own cell delay profile whose correlation value is equal to or more than the average value of the correlation values of the own cell delay profile, and delays the cell search. A configuration is adopted in which the path at the above timing is deleted from the profile.

According to this configuration, the threshold value processing is performed by multiplying the correlation value of the own cell timing by the coefficient for the timing of another cell having the same timing as the own cell timing,
Even if the path timings of the other cell and the own cell are the same, it is possible to detect the valid path timing of the other cell without deleting the path timing of the own cell.

In the wireless communication device of the present invention, the deleting means compares the cell search delay profile and the own cell delay profile for each path having the same reception timing, and determines the path of the cell search delay profile and the own cell delay. When the difference between the profile paths is equal to or smaller than a predetermined value, the path of the reception timing is deleted from the cell search delay profile.

According to this structure, when the correlation value of the path timing of the own cell is small, the relative threshold value for each path is small, and the correlation value of the other cell is small, the probability of not determining the invalid other cell timing as valid is high. It is possible to improve and reduce the number of unnecessary three-step cell search processes.

In the radio communication apparatus of the present invention, the delay profile creating means creates a cell search delay profile which is a correlation between the received signal and the first synchronization code commonly used in a plurality of cells, and the other cell searching means First processing means for detecting the timing of identifying a scramble code used by a candidate for a communication partner by using a cell search delay profile obtained by removing a signal path of communication between the local station and the communication partner in the deleting means, and the timing. Second processing means for identifying a group of scramble codes used by the communication partner candidate from the correlation result between the received signal and the second synchronization code.
And a third processing means for identifying the scrambling code used by the communication partner candidate from the correlation result between the scramble code belonging to the identified scrambling code group and the received signal.

According to this structure, it becomes possible to introduce the three-step cell search system only to the received signals of other cells,
The other cell search time can be greatly reduced.

According to the cell search method of the present invention, a cell search delay profile, which is a correlation between a received signal and a synchronization code commonly used in a plurality of cells, is created, and the cell search delay profile is used to communicate with the local station. The signal path in the communication with the other party is removed, and the information of the cell which is the communication partner candidate of the own station is acquired from the cell search delay profile from which the path is removed.

According to this method, in the other cell search for searching for a candidate for a communication partner, the communication of the local station is performed based on the delay profile showing the correlation between the midamble code of the signal used when the local station communicates with the communication partner and the received signal. By selecting the path of the signal transmitted from the other party and removing this path from the delay profile for cell search and performing another cell search, the path of the own cell can be excluded from other cell search targets. The cell search can be performed at high speed.

[0045]

BEST MODE FOR CARRYING OUT THE INVENTION In the other cell search in which the communication terminal apparatus detects the code of the base station of the communication partner candidate, since the code for performing the correlation calculation is common to all cells, it is not possible to distinguish between the own cell and other cells. , The code identification process from the second stage onward is performed for all paths in descending order of correlation value. As a result, the path of the own cell, which is unnecessary for the processing of other cell search, is also processed.

In particular, when the cell search is performed stepwise in three steps from the first step to the third step, the cell search from the first step to the third step is performed for the path including the scrambling code of the detected own cell. As a result of performing processing and determining that it is not the scrambling code of another cell,
Returning to the first stage, the processes from the second stage onward are repeatedly performed on the delayed waves of the own cell at path timings other than the one at which the three-step cell search method was previously performed. As a result, the cell search process is performed in three steps even for a path that is not the target of another cell search, and thus it takes extra time.

The present inventor came to the present invention by focusing on the fact that, of the delay profile paths, the path transmitted by the communication partner of the own station is not the target of other cell search.

That is, the essence of the present invention is that in CDMA communication, the path of the communication partner of the own station is removed from the delay profile showing the correlation between the synchronization code and the received signal, and the communication partner candidate of the own station is identified from the removed delay profile. This is to identify the code to be used and perform another cell search.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. (Embodiment 1) In Embodiment 1, in another cell search for searching for a candidate for a communication partner, a self profile is selected from a delay profile indicating a correlation between a midamble code of a signal used when the local station communicates with a communication partner and a received signal. The path of the signal transmitted from the communication partner of the station is selected, and this path is removed from the delay profile for cell search to perform another cell search.

FIG. 1 is a block diagram showing the configuration of a radio receiving apparatus according to Embodiment 1 of the present invention. In FIG. 1, the wireless reception device 100 includes an antenna 101 and a reception R.
F section 102, A / D conversion section 103, and A / D conversion section 1
04, the timing control unit 105, and the code control unit 10
6, the code generation unit 107, and the matched filter unit (M
F) 108, a switch circuit 109, a cell search memory 110, a first-stage processing unit 111, a second-stage processing unit 112, a third-stage processing unit 113, and its own cell determination unit 1
14, the other cell detection number determination unit 115, the communication channel memory 116, the reception unit 117, the demodulation unit 118, and the own cell timing deletion unit 119.

The antenna 101 receives a radio signal.
The reception RF unit 102 frequency-converts the radio signal received by the antenna 101 from a carrier frequency to a baseband frequency, and the in-phase component of the obtained reception signal is A / D conversion unit 10.
3 and outputs the quadrature component of the received signal to the A / D conversion unit 104.
Output to. Hereinafter, the in-phase component of the received signal is described as I-ch and the quadrature component is described as Q-ch.

A / D converter 103 and A / D converter 10
Reference numeral 4 converts the reception signal converted into the baseband frequency from an analog signal into a digital signal, and converts the reception signal after conversion into a matched filter unit 108 and a second stage processing unit 11
2 to the third stage processing unit 113 and the receiving unit 117.

Radio receiving apparatus 100 uses the received signal converted into a digital signal to identify the frame timing of another cell and the scrambling code which is a cell-specific code.

First, the timing control section 105 sets the reception timing of its own cell in the code control section 106. The code control unit 106 instructs the operation of the code generation unit 107 by matching the output of the system-specific code (primary synchronization code) used in the first step of the three-step cell search method with the reception timing of the own cell.
This primary synchronization code is a code commonly used by a plurality of cells.

Further, the timing control section 105 adjusts the output of the code (secondary synchronization code) for identifying the group of scrambling codes used in the second step of the three-step cell search method to the reception timing of its own cell, It instructs the operation of the code generation unit 107.

Then, the timing control section 105 instructs the operation of the code generation section 107 in accordance with the output of the scrambling code used in the third step of the three-step cell search method in accordance with the reception timing of its own cell.

The code generator 107 includes a code controller 10
According to the instructions of 6, the primary synchronization code, the secondary synchronization code,
A scrambling code or a midamble code is generated and output to the matched filter unit 108. The matched filter unit 108 includes the code output from the code generation unit 107, the A / D conversion unit 103, and the A / D conversion unit 10.
The correlation calculation of the output signal of 4 is performed.

The switch circuit 109 is used in the code controller 10
The output destination of the correlation result is switched based on the determination result of the cell search mode or the communication channel mode in 6. When the operation of the wireless reception device 100 is in the cell search mode, the switch circuit 109 outputs the correlation result to the cell search memory 1
Output to 10. When the operation of the wireless reception device 100 is in the communication channel mode, the switch circuit 109 outputs the correlation result to the communication channel memory 116. In addition,
The communication channel mode includes not only the case of receiving the communication channel but also the accumulation of the delay profile used for tracking the frame timing of the own cell even in the standby mode.

The cell search memory 110 accumulates the correlation result output from the switch circuit 109 and outputs it to the first stage processing section 111 and the own cell timing deleting section 119. Further, the communication channel memory 116 is a code (for example, a midamble code) used for communication with a communication partner.
The timing control unit 1 accumulates the correlation result between the received signal and the received signal.
05 and its own cell timing deletion unit 119.

The own cell timing deleting unit 119 extracts the timing of the path of the own cell, that is, the timing of the path of the signal with which the own station is communicating with the communication partner, from the delay profile output from the communication channel memory 116, The path at the timing of the path of the own cell is deleted from the delay profile output from the cell search memory 110. Specifically, the own cell timing deletion unit 119
Sets the correlation value at the timing of the path of its own cell to “0” from the delay profile output from the cell search memory 110.

First stage processing section 111 detects the next candidate timing of another cell from the correlation result output from own cell timing removing section 119. Here, the next candidate timing indicates the timing of a path of a signal from another cell included in the delay profile.

The second-stage processing section 112 includes the A / D conversion section 1
03 and the output signals of the A / D conversion unit 104 and the code timing output from the timing control unit 105, the frame timing and the code group of the scrambling code are identified. The frame timing is controlled by the code control unit 10 via the timing control unit 105.
6 is output.

The code control unit 106 is the third stage processing unit 1.
The code generation section 107 is instructed of the code used in step 13 and the code timing. The code generation unit 107 creates a code to be used in the third stage processing unit 113 and outputs it to the third stage processing unit 113 at the code timing instructed by the code control unit 106.

The third-stage processing unit 113 includes the A / D conversion unit 1
03 and the output signal of the A / D converter 104 and the code generated by the code generator 107,
The code with the highest correlation value is identified as the scrambling code of another cell.

The own cell determination unit 114 is used for the signals received by the scrambling code identified by the third stage processing unit 113 and the output signals of the A / D conversion unit 103 and A / D conversion unit 104. The code of the own cell is compared, and the comparison result is output to the other cell detection number determination unit 115.

When the scrambling code identified by the third stage processing unit 113 is the same as the code of the own cell used for the received signal, the other cell detection number determination unit 115 determines that the other cell has not been detected. It outputs to the first-stage processing unit 111 that the timing detected by the first-stage processing unit 111 is the pass timing of the own cell without counting the number of detected cells.

When the operation of radio receiving apparatus 100 is in the communication channel mode, switch circuit 109 outputs the correlation result to communication channel memory 116.

On the other hand, the receiving section 117 includes an A / D conversion section 10
3 and the output signals of the A / D converter 104 to the code generator 1
The code output from 07 is subjected to soft decision processing at the timing designated by the timing control section 105, and the soft decision result is output to the demodulation section 118. The demodulation unit 118 performs hard decision processing from the soft decision result and demodulates the received data.

Radio receiving apparatus 100 has first stage processing section 111 until it reports all other cell frame timings and scrambling codes designated by the base station.
To the own cell determination unit 114 are repeated.

Next, radio receiving apparatus 1 according to the present embodiment
The delay profile used for the 00 cell search will be described. FIG. 2 is a diagram showing an example of a delay profile of a received signal. In FIG. 2, the horizontal axis represents the reception timing time, and the vertical axis represents the correlation value level. Also,
W indicates the window width for processing with the delay profile. Figure 2
A is a delay profile used in the cell search mode. FIG. 2B is a delay profile used in the communication channel mode. Then, FIG. 2C is a delay profile used in the present embodiment.

The delay profile of FIG. 2A is stored in the cell search memory 110 because of the cell search mode. In the delay profile of FIG. 2B, the frame timing for the own cell is generated in the communication channel memory 116 by generating the delay profile for tracking the frame timing regardless of communication and standby.

All own cell timings including delayed waves are
By referring to the information accumulated in the communication channel memory 116, the timing can be known.

The radio receiving apparatus 100 of the present invention feeds back the own cell timing information accumulated in the communication channel memory 116 to the cell search memory 110 and deletes the path of the own cell, so that FIG. The delay profile of the cell search can be obtained only for the received signals of the other cells (base station B, base station C) to be detected.

For example, in the radio receiving apparatus 100, the cell search memory 1 is
For the delay profile stored in 10, the timing of the own cell is deleted from the delay profile information stored in the communication channel memory 116 (correlation value is set to “0”), and this delay profile is processed in the first stage. Part 111
To enter.

By this operation, the received signal of the own cell and the received signal of the other cell, which are factors that increase the other cell search time, are distinguished, and the three-step cell search system is introduced only in the reception timing of the received signal of the other cell. You can

Next, the operation of the radio reception apparatus according to this embodiment will be explained. FIG. 3 is a flowchart showing an example of the operation of the wireless reception device according to the present embodiment.

In FIG. 3, steps (hereinafter, referred to as "ST")
In step 301, the own cell timing deleting unit 119 deletes the signal path of the own cell from the cell search delay profile.

In ST302, first stage processing section 111 detects the next candidate timing of another cell from the delay profile in which the signal path of the own cell is deleted. ST
In 303, the second stage processing unit 112 identifies the code group of the scrambling code. ST3
In 04, the scrambling code is identified in the third stage processing unit 113.

In ST305, own cell determining section 114 determines whether or not the identified scrambling code matches the scrambling code used in the own cell. If the identified scrambling code matches the scrambling code used in the own cell, ST301
Return to. If the identified scrambling code does not match the scrambling code used in the own cell, the process proceeds to ST306.

In ST306, the other cell detection number determination unit 11
In 5, it is determined whether or not all the other cell frame timings and scrambling codes of the number m designated by the base station have been detected. When the number m of other cell frame timings and scrambling codes designated by the base station are not detected, the process returns to ST301.
When the base station detects all other cell frame timings and scrambling codes of the specified number m, the cell search process is terminated.

As described above, according to the radio receiving apparatus of this embodiment, in the other cell search for searching for a communication partner candidate,
From the delay profile showing the correlation between the midamble code of the signal used when the local station communicates with the communication partner and the received signal, select the path of the signal transmitted from the local station's communication partner and select from the delay profile for cell search By removing this path and performing another cell search, the path of the own cell can be excluded from the other cell search target, and the other cell search can be performed at high speed.

Specifically, the radio receiving apparatus according to this embodiment feeds back the communication channel memory 116 for the own cell to the cell search memory 110 to distinguish the own cell timing from the other cell timing. Yes, by deleting own cell timing in advance,
It is possible to eliminate the repetition of the processing loop from ST301 to ST304 in FIG. Therefore, the three-step cell search method can be introduced only to the received signals of other cells, and the other cell search time can be greatly reduced.

It should be noted that the deletion of the timing of the own cell means that the processing of setting the correlation value of only the path timing of the own cell (the path having the maximum value at a certain threshold value or more) to "0" is deleted. There is.

(Embodiment 2) FIG.4 is a block diagram showing a configuration of a radio reception apparatus according to Embodiment 2 of the present invention. However, the same components as those in FIG. 1 are denoted by the same reference numerals as those in FIG. 1, and detailed description thereof will be omitted.

The radio receiving apparatus 400 of FIG. 4 is provided with the same path timing differentiator 401, and subtracts the delay profile of the signal of the own cell from the delay profile for cell search on a path-by-path basis to communicate between itself and the communication partner. 1 is different from the wireless reception device in FIG.

The cell search memory 110 accumulates the correlation result output from the switch circuit 109 and outputs it to the same path timing differencer 401 as the first stage processing unit 111. Further, the communication channel memory 116 is a code (for example, a midamble code) used for communication with a communication partner.
The timing control unit 1 accumulates the correlation result between the received signal and the received signal.
05 and the same path timing differencer 401.

The same path timing differentiator 401 subtracts the delay profile output from the communication channel memory 116 from the delay profile output from the cell search memory 110 on a path-by-path basis, and obtains the delay profile obtained as a result of the subtraction. Output to the first stage processing unit 111.

The first stage processing unit 111 detects the next candidate timing of another cell from the correlation result output from the same path timing differencer 401. Here, the next candidate timing indicates the timing of a path of a signal from another cell included in the delay profile.

Next, radio receiving apparatus 4 according to the present embodiment
The delay profile used for the 00 cell search will be described. FIG. 5 is a diagram showing an example of a delay profile of a received signal. In FIG. 5, the horizontal axis represents the reception timing time, and the vertical axis represents the correlation value level. Also,
W indicates the window width for processing with the delay profile. Figure 5
A is a delay profile used in the cell search mode. Further, FIG. 5B is a delay profile used in the communication channel mode. Then, FIG. 5C is a delay profile used in the present embodiment.

In FIG. 5A, path 511 and path 512
Indicates the signal path of the own cell, and the path 513 and the path 51
Reference numeral 4 indicates a path in which the signal path of the own cell and the signal path of another cell overlap. Also, pass 515 and pass 516
Indicates a signal path of another cell.

The same path timing differencer 401 is shown in FIG.
Paths 521 and 52 detected by the delay profile of B
2, 523, and 524 are extracted as the paths of the signals of the own cell, and the paths 511 and 51 of FIG.
3, 514, 512 and paths 521, 522, 523, 5
Take the difference of 24 correlation values.

FIG. 5C shows the same path timing differencer 40.
1 is a delay profile obtained by taking the difference between the correlation values of the paths. In FIG. 5C, the path 531 is the path 513.
Is the result of subtracting the path 522 from. Also, pass 53
3 is the result of subtracting the path 523 from the path 514.

The path 532 is the path 515 of FIG. 5A.
And path 534 is path 516 of FIG. 5A. In FIG. 5B, the path having the same timing as these two paths is not extracted as the path of the own cell and is not the target of subtraction.

Further, in FIG. 5C, the path of the signal of the own cell is deleted as a result of subtracting the path 521 from the path 531. Similarly, in FIG. 5C, the path of the signal of the own cell is deleted as a result of subtracting the path 524 from the path 532.

As described above, according to the radio receiving apparatus of this embodiment, the paths 531 and 533 in FIG. 5C can be left as candidates for other cell timing, and a more effective path timing of another cell can be detected. It will not be damaged,
Handover with stable quality can be performed.

Next, the operation of the radio reception apparatus according to this embodiment will be explained. FIG. 6 is a flowchart showing an example of the operation of the wireless reception device according to the present embodiment.

In FIG. 6, in ST601, the same path timing differentiator 401 subtracts the signal path of its own cell from the cell search delay profile.

In ST602, first stage processing section 111 detects the next candidate timing of another cell from the delay profile in which the signal path of the own cell is deleted. ST
At 603, the second-stage processing unit 112 identifies the code group of the scrambling code. ST6
In 04, the scrambling code is identified in the third stage processing unit 113.

In ST605, own cell determining section 114 determines whether or not the identified scrambling code matches the scrambling code used in the own cell. If the identified scrambling code matches the scrambling code used in the own cell, ST601
Return to. If the identified scrambling code does not match the scrambling code used in the own cell, the process proceeds to ST606.

In ST606, other cell detection number determination section 11
In 5, it is determined whether or not all the other cell frame timings and scrambling codes of the number m designated by the base station have been detected. When the number m of all other cell frame timings and scrambling codes designated by the base station are not detected, the process returns to ST601.
When the base station detects all other cell frame timings and scrambling codes of the specified number m, the cell search process is terminated.

As described above, according to the radio receiving apparatus of this embodiment, the delay profile of the signal of the own cell is subtracted from the delay profile for cell search on a path-by-path basis to obtain the signal of the communication between the own station and the communication partner. By deleting the path, the path at the same timing as the own cell timing and the timing of another cell can be left in the delay profile, and the frame timing and scrambling code of another cell at the same cell timing as the own cell timing Can be detected.

The path timing of FIG. 5 is described as a specific path timing for the sake of simplicity of explanation. However, this is performed when the calculation amount is reduced and If there is a margin, the correlation value of the delay profile corresponding to the window width in W, or the delay profile obtained by all the differences may be used. As a result, all the autocorrelation components of the own cell are deleted, and the delay profile can be generated for other cells.

(Embodiment 3) FIG.7 is a block diagram showing a configuration of a radio reception apparatus according to Embodiment 3 of the present invention. However, the same components as those in FIG. 1 are denoted by the same reference numerals as those in FIG. 1, and detailed description thereof will be omitted.

Radio receiving apparatus 700 of FIG. 7 has same path timing determining section 701 and own cell timing deleting section 70.
2 is provided, and the timing of another cell having the same timing as the own cell timing is determined by multiplying the correlation value of the own cell timing by a coefficient to perform threshold processing to determine whether or not the same timing is satisfied. Different from the device.

The cell search memory 110 accumulates the correlation result output from the switch circuit 109 and outputs it to the first-stage processing unit 111, the same-path timing determining unit 701, and the own cell timing deleting unit 702. Further, the communication channel memory 116 accumulates the correlation result between the code (for example, a midamble code) used for communication with the communication partner and the received signal, and outputs the result to the timing control unit 105 and the own cell timing deletion unit 702.

The same path timing determination unit 701 extracts the timing of the path of its own cell, that is, the timing of the path of the signal with which the local station is communicating with the communication partner, from the delay profile output from the communication channel memory 116. It is output to the own cell timing deletion unit 702.

The own cell timing deletion unit 702 determines the communication channel from the correlation value of the path of the delay profile output from the cell search memory 110 at the timing of the path of the signal which the local station is communicating with the communication partner. The correlation value of the path of the delay profile output from the memory 116 is subtracted, and the path whose subtraction result is a predetermined value or less is deleted from the delay profile output from the cell search memory 110. Specifically, the own cell timing deleting unit 702 sets the correlation value at the timing of the path of the own cell to “0” from the delay profile output from the cell search memory 110.

First stage processing section 111 detects the next candidate timing of another cell from the correlation result output from own cell timing deleting section 702. Here, the next candidate timing indicates the timing of a path of a signal from another cell included in the delay profile.

Next, radio receiving apparatus 7 according to the present embodiment
The delay profile used for the 00 cell search will be described. FIG. 8 is a diagram showing an example of a delay profile of a received signal. In FIG. 8, the horizontal axis represents the reception timing time, and the vertical axis represents the correlation value level. Also,
W indicates the window width for processing with the delay profile. Figure 8
8A and 8C are delay profiles used in the cell search mode. Further, FIG. 8B is a delay profile used in the communication channel mode. And FIG. 8D
Is a delay profile used in the present embodiment.

In FIG. 8A, the path 811 is a path 8
Reference numeral 12 indicates a signal path of the own cell, and paths 813 and 814 indicate paths where a signal path of the own cell and a signal path of another cell overlap. Also, pass 815 and pass 81
Reference numeral 6 denotes a signal path of another cell.

As shown in FIG. 8A, when the same code (primary synchronization code) is used between the base stations (cells), the delay profile accumulated in the cell search memory 110 is the timing of its own cell. And the timing of other cells overlap. As shown in FIG. 8A, pass 8
13 and the path of path 814 are correlation values C (813), C
(814) becomes large.

From this input signal, as shown in FIG. 8B, threshold determination processing is performed at the timing of paths 821, 822, 823 and 824 of the own cell. As shown in FIG. 8C, a threshold is set for each path. The correlation value of each path timing of the own cell is C (821), C (822), C
(823), C (824), and the relative value α for each pass
To set the threshold. The threshold for each path is αC (821),
It becomes αC (822), αC (823), and αC (824).

It is determined that the path timing exceeding these thresholds is the same as the path timing of another cell,
The deletion is not performed as the path of the own cell, and the three-step cell search is performed as the timing of the path of the other cell. The same path timing determination unit 701 outputs the determination result to the own cell timing deletion unit 119. As shown in FIG. 8C, the determination results of the path timing exceeding the threshold value are the path 832 and the path 833. For example, (αC (832) <C (83
2) and αC (833) <C (833)), the paths 832 and 833 are determined to be the same as the timing of the paths of other cells, and the deletion is not performed as the path of the own cell.

The own cell timing deleting unit 119 deletes the path timing of the own cell other than the path timing of the own cell which is determined to be the same timing as the other cell, and sets the correlation value to 0.
Set to. As a result, the result is as shown in FIG. 8D. The output signal of the own cell timing deletion unit 119 is input to the first stage processing unit 111.

Next, the operation of the radio receiving apparatus according to this embodiment will be explained. FIG. 9 is a flowchart showing an example of the operation of the wireless reception device according to the present embodiment.

In ST901, in ST901, the same-path timing determination section 701 extracts the timing of the path of the own cell, that is, the timing of the path of the signal with which the own station communicates with the communication partner. In ST902, the own cell timing deleting section 702 deletes the signal path of the own cell from the delay profile for cell search.

In ST903, first stage processing section 111 detects the next candidate timing of another cell from the delay profile in which the signal path of the own cell is deleted. ST
At 904, the second-stage processing unit 112 identifies the code group of the scrambling code. ST9
In 05, the scrambling code is identified in the third stage processing unit 113.

In ST906, own cell determining section 114 determines whether or not the identified scrambling code matches the scrambling code used in the own cell. If the identified scrambling code matches the scrambling code used in the own cell, ST901
Return to. If the identified scrambling code does not match the scrambling code used in the own cell, the process proceeds to ST907.

In ST907, other cell detection number determination section 11
In 5, it is determined whether or not all the other cell frame timings and scrambling codes of the number m designated by the base station have been detected. When the number m of other cell frame timings and scrambling codes designated by the base station are not detected, the process returns to ST901.
When the base station detects all other cell frame timings and scrambling codes of the specified number m, the cell search process is terminated.

As described above, according to the radio receiving apparatus of the present embodiment, the timing of another cell having the same timing as the own cell timing is multiplied by the coefficient of the correlation value of the own cell timing to perform threshold processing. Even if the path timings of the other cell and the own cell are the same, it is possible to detect the valid path timing of the other cell without deleting the path timing of the own cell.

Further, since the threshold value is set relatively to the correlation value of the own cell, it is possible to detect the timing of another cell even in a fading environment.

In the above description, the threshold value processing of the same path timing determination unit 701 determines with the relative value of the path timing of the own cell, but not limited to this, the average value of all delay profiles in the own cell. Calculate Cave, determine the relative value β to this average value, and set the threshold β common to all paths.
It is also possible to set Cave and determine only the path timing of the own cell and the path exceeding this threshold as the timing of another cell.

FIG. 10 is a diagram showing an example of the delay profile of the received signal. In FIG. 10, the horizontal axis represents the reception timing time, and the vertical axis represents the correlation value level.
W indicates the window width to be processed by the delay profile. 10A and 10C are delay profiles used in the cell search mode. Further, FIG. 10B is a delay profile used in the communication channel mode. Then, FIG. 10D is a delay profile used in the present embodiment.

Further, as shown in FIG. 10B, the average value Cave of all delay profiles in the own cell is calculated,
A relative value β is determined for the average value, and as shown in FIG. 10C,
A threshold βCave common to all paths is set, and only the path timing of the own cell and only the paths exceeding this threshold are determined to be the timing of other cells. That is, the timing of exceeding the two threshold values in the path timing of the own cell is determined as the timing of the other cell. Therefore, in the own cell timing deleting unit 702, based on the determination result of the same path timing determining unit 701, only the effective other cell timing remains unchanged, and the other own cell timing and the path timing of the other cell timing with a small received signal are used. Set the correlation value to 0.

As described above, according to the radio receiving apparatus of this embodiment, the correlation value of the path timing of the own cell is small,
When the relative threshold for each path is also small and the correlation value of the other cell is small, the probability of not determining invalid other cell timing as valid is improved, and useless three-step cell search processing can be reduced.

In the description of each embodiment, an example of three-step cell search is explained, but the present invention is not limited to this, and
The wireless reception device of the present invention can be applied as long as it performs another cell search using the delay profile of the received signal.

Further, in the present invention, the synchronization code that correlates with the received signal can distinguish the signal communicated between itself and the communication partner of the own station from the signal of the communication partner candidate of the own station. Sync code commonly used in multiple cells,
Alternatively, any synchronization code different for each cell can be used.

For example, as a synchronization code commonly used in a plurality of cells, there is a Primary Synchronization Code in the 3.84 Mcps TDD Option system. Also, as a synchronization code different for each cell, there is a SYNC # DL Code in the 1.28 Mcps TDD Option system.

Further, the wireless communication device of the present invention can be mounted on a communication terminal device to perform another cell search. Also,
The wireless communication device of the present invention can be used in both an asynchronous system and a synchronous system of a CDMA system.

[0130]

As described above, according to the wireless communication device and the cell search method of the present invention, in CDMA communication, a delay profile indicating a correlation between a common synchronization code commonly used by a plurality of cells and a received signal. The path of the communication partner of the local station is removed from the cell, the code used by the candidate communication partner of the local station is identified from the removed delay profile, and another cell search is performed to distinguish only the path of the signal of the other cell and A search can be performed, and another cell search can be performed at high speed.

[Brief description of drawings]

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

FIG. 2 is a diagram showing an example of a delay profile of a received signal.

FIG. 3 is a flowchart showing an example of the operation of the wireless reception device according to the above embodiment.

FIG. 4 is a block diagram showing a configuration of a wireless reception apparatus according to Embodiment 2 of the present invention.

FIG. 5 is a diagram showing an example of a delay profile of a received signal.

FIG. 6 is a flowchart showing an example of the operation of the wireless reception device according to the above embodiment.

FIG. 7 is a block diagram showing a configuration of a wireless reception apparatus according to Embodiment 3 of the present invention.

FIG. 8 is a diagram showing an example of a delay profile of a received signal.

FIG. 9 is a flowchart showing an example of the operation of the wireless reception device according to the above embodiment.

FIG. 10 is a diagram showing an example of a delay profile of a received signal.

FIG. 11 is a diagram showing an example of a conventional wireless communication system.

FIG. 12 is a block diagram showing a configuration of a conventional wireless reception device.

FIG. 13 is a flowchart showing an example of the operation of a conventional wireless reception device.

FIG. 14 is a diagram showing an example of a delay profile in the first stage of cell search.

[Explanation of symbols]

105 Timing control unit 106 code control unit 107 code generator 108 Matched filter section 109 switch circuit 110 cell search memory 111 First Stage Processing Unit 112 Second Stage Processing Unit 113 Third Stage Processing Unit 114 own cell determination unit 115 Other cell detection number determination unit 116 Communication channel memory 119, 702 Own cell timing deletion unit 401 Same path timing differencer 701 Same path timing determination unit

Claims (10)

[Claims] 1. A delay profile creating means for creating a delay profile for cell search, which is a correlation between a synchronization code and a received signal, and a signal path in communication between itself and a communication partner is removed from the delay profile for cell search. A wireless communication apparatus comprising: a deleting unit and a cell searching unit that performs a cell search from the delay profile for cell search from which the path is removed by the deleting unit. 2. The wireless communication device according to claim 1, wherein the delay profile creating means creates a cell search delay profile that is a correlation between a synchronization code commonly used in a plurality of cells and a received signal. . 3. The wireless communication apparatus according to claim 1, wherein the delay profile creating means creates a cell search delay profile which is a correlation between a synchronization code and a received signal which is different for each cell. 4. The delay profile creating means creates an own cell delay profile which is a correlation between a received signal and a midamble code used for a communication signal between the own station and a communication partner, and the deleting means creates the own cell delay profile. 2. The path of the signal for communication between the local station and the communication partner is removed from the delay profile for cell search using the profile.
4. The wireless communication device according to claim 3. 5. The deleting means deletes a path at a timing at which a signal path for communication between itself and a communication partner exists from the delay profile for cell search, according to any one of claims 1 to 4. The wireless communication device as described in. 6. The deleting means deletes the signal path of the communication between the own station and the communication partner by subtracting the own cell delay profile from the cell search delay profile on a path-by-path basis. The wireless communication device described. 7. The deleting unit selects a timing of a path having a correlation value equal to or more than an average value of correlation values of the own cell delay profile among paths of the own cell delay profile, and selects the timing from the delay profile for cell search. The wireless communication device according to claim 4, wherein the path is deleted. 8. The deleting means compares the cell search delay profile with the own cell delay profile for each path having the same reception timing, and determines the difference between the path of the cell search delay profile and the own cell delay profile. The wireless communication device according to claim 4, wherein when the value is equal to or less than a predetermined value, the path of the reception timing is deleted from the delay profile for cell search. 9. The delay profile creating means creates a cell search delay profile that is a correlation between a received signal and a first synchronization code commonly used in a plurality of cells, and the other cell searching means uses its own means in the deleting means. First processing means for detecting a timing of identifying a scramble code used by a candidate for a communication partner by using a delay profile for cell search in which a path of a signal for communication with a communication partner is removed, and a received signal and a second signal at the timing. Second processing means for identifying the group of scramble codes used by the communication partner candidate based on the correlation result with the synchronization code, and the communication partner from the correlation result between the scramble code belonging to the identified scrambling code group and the received signal. Third processing means for identifying the scrambling code used by the candidate. The wireless communication device according to any one of claims 1 to 8. 10. A delay profile for cell search, which is a correlation between a received signal and a synchronization code commonly used in a plurality of cells, is created, and a signal path in communication between the local station and a communication partner is created from the delay profile for cell search. Remove
A cell search method, characterized in that information on a cell that is a communication partner candidate of the local station is acquired from the delay profile for cell search from which the path has been removed.