JP2000040981A - Rake receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the omission of data at the switching time of path allocation. SOLUTION: In this rake receiver provided with plural fingers 111-113 for applying inverse spreading processing to the desired signal coming via the allocated path among multi-path and outputting an inverse spreading signal provided by the inverse spreading processing while adding a delay amount corresponding to this path, combining part 12 for combining the outputs of the respective finger parts and path search part 13 for allocating the path to each finger part, at the path search part 13, a correlation detecting part 31 detects the correlation of received wave and desired wave and outputs a correlation value and correlation detecting time, a path selecting part 33 selects the path, through which the desired signal to apply inverse spreading comes, based on the correlation value, a path follow-up part 34 decides whether, or not the selected path is equal with a path allocated to each finger part up to the moment, based on the detection timing of the correlation value. When it is the same path, the finger part of the same up to the moment executes inverse spreading and delay control processing with respect to the desired signal coming through the selected path.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rake receiver in a spread spectrum communication system (hereinafter referred to as DS) by direct spread, and more particularly to a variation in received electric field strength, phase and delay due to multipath fading which is a problem in mobile communication. The present invention relates to a rake receiver capable of improving the reception characteristics of the rake receiver.

[0002]

2. Description of the Related Art DS-CDMA (Direct S-CDMA) is a next-generation mobile communication system that realizes wireless multimedia communication.
2. Description of the Related Art A digital cellular radio communication system using an equence Code Division Multiple Access (direct spreading code division multiple access) technique is being developed. In such CDMA communication, transmission information of a plurality of channels or users is multiplexed by a spreading code and transmitted through a transmission path such as a wireless line. In mobile communications, random amplitude and phase changes and fading occur with a maximum frequency determined by the speed of the mobile object and the frequency of the carrier wave, making stable reception extremely difficult compared to fixed wireless communications. . A spread spectrum communication system is effective as a means for reducing such deterioration due to the frequency selective fading. This is because a narrow band signal is spread and transmitted in a high band, so that even if a drop in the received electric field strength occurs in a certain specific frequency band, information can be restored from other bands with few errors.

In mobile communication, if a fading similar to the above occurs due to an environment around a receiver due to a delayed wave from a distant high-rise building or a mountain, a multipath fading environment occurs. In the case of DS, the delayed wave becomes an interference wave with respect to the spreading code, and thus causes deterioration of reception characteristics. As one of the methods for positively using the delayed wave to improve characteristics, RA
The KA reception method (rake reception method) is known. In this method, despreading is performed for each delay wave arriving via each path of the multipath, delay times are made uniform, and weighted according to the reception level and added to combine.

FIG. 18 shows a configuration example of a general radio.
1 is a transmission system circuit, 2 is a reception system circuit, 3 is a duplexer for transmitting a transmission signal to an antenna and inputting a reception signal to the reception system circuit, and 4 is an antenna. In the transmission system circuit 1,
1a is a coder for coding a transmission signal (transmission data);
Reference numeral 1b denotes a mapping unit which, for example, alternately distributes frame data (pilot signal and transmission data) one bit at a time to an in-phase component (I component: In-Phase compornent).
Data that is converted into two series of I symbol data D _I and Q symbol data D _Q of data and quadrature component (Q component: Quadrature compornent) data, 1c and 1d are I symbol data,
A spreader that performs spread modulation on the Q symbol data D _I and D _Q using a predetermined spreading code, 1e and 1f are waveform shaping filters, and 1g and 1h are outputs of the filters 1e and 1f.
A DA converter for conversion, 1i is a quadrature modulation circuit for performing QPSK quadrature modulation on the Ich signal and Qch signal and outputting the result, 1j
Is a radio unit for performing frequency conversion to IF or RF, high-frequency amplification, and the like. In the receiving circuit 2, 2a is a radio unit for performing frequency conversion to RF or IF, high-frequency amplification, etc., 2b is a quadrature detection circuit for demodulating Ich and Qch signals by quadrature detection, and 2c and 2d are Ich and Qch signals. An AD converter for converting to digital, 2e is a path search circuit for searching for multipaths, 2f is a rake combining / demodulating unit, which performs despreading processing for each multipath path, and obtains I symbol data obtained by despreading. , Q symbol data D _I ′ and D _Q ′ are demodulated to the original data, and the demodulation result is synthesized and output, and 2g is a decoder.

FIG. 19 shows a path search section and rake combining / demodulating.
It is a block diagram of a part. The rake combining / demodulating unit 2 f
Finger part 5 provided for each path of the path₁,
5_Two, 5 _ThreeRake synthesis that combines the output of each finger
It has a part 6. The path search unit 2e matches
(MF: matched filter) 7a, integrating circuit 7b, path
A selection unit 7c for detecting a multipath,
There is an arrival time of the signal arriving via each path constituting
Or the delay time from the reference time, and according to each path
Despreading start timing data and delay at finger
Enter the time adjustment data.

The reception level of a signal transmitted from a transmitter changes according to multipath as shown in FIG. 20, and the arrival time at the receiver also differs. Therefore, the matched filter 7a outputs the autocorrelation of the desired signal included in the received signal. Since the reception output of the antenna 4 includes channel components other than the channel assigned to itself, the matched filter 7a uses the spreading code of the own channel to convert the signal component of the own channel (the desired signal) from the antenna reception signal. ) Is extracted and output. In this case, since the correlation values I and Q of the Ich signal and the Qch signal are obtained independently,
For example, an operation of (I + jQ) (I−jQ) = I ² + Q ² is performed to output a power value.

That is, when a direct spread signal (DS signal) affected by multipath is input, the matched filter 7a outputs a pulse train having a plurality of peaks corresponding to the arrival delay time and the received electric field strength, The data is input to the path selection unit 7c through 7b. The path selection section 7c refers to the integrated output (FIG. 20) of the integration circuit, detects a multipath based on the multipath signals MP ₁ , MP ₂ , and MP _{3 that} are larger than the threshold value, and detects each path constituting the multipath. and delay times t _1, t _2, detects the t _3, the finger portions 5 _1, 5 _2, 5 timing data P ₁ despreading start to _3, P corresponding to each path
_2, P ₃ and delay time adjustment data D _1, D _2, and inputs the D _3. Note that the multipath signals MP ₁ , MP ₂ , and MP ₃ are arranged in the order of their magnitudes, the path having the largest multipath signal is assigned to the _first finger 51, and the path having the second magnitude is assigned to the _first finger 51. assigned to the second finger 5 _2, multipath signals of the third allocation size of the path to the third finger _3, the following processing to each finger unit signals arriving via the assigned path Do.

[0008] Finger portions 5 ₁ , 5 ₂ , 5 corresponding to each path
₃ has the same configuration and includes a despreading circuit 5a, a demodulation circuit 5b, and a delay circuit 5c. Despreading circuit 5a instructed by the path search unit 2e timing (P ₁ ~
In P ₃ ), the received Ich signal and Qch signal are subjected to despreading processing using the spreading code of the own channel. The demodulation circuit 5b demodulates the original data using the I symbol data D _I 'and the Q symbol data D _Q ' obtained by the despreading, and
c is the time instructed by the path search unit 2e (D ₁ ~D ₃₎
Output with delay. As a result, each finger section despreads at the same timing as the spreading code of the transmitter, adjusts the delay time according to the path, aligns the phase, and adjusts the phase.
And a rake combining unit combines the input signals and outputs the combined signal.

FIG. 21 shows an example of the configuration of a despreading circuit in the finger portion, in which despreading processing can be performed on each of the Ich signal and the Qch signal. Numeral 8a denotes a spreading code generator for generating the same spreading code as that of the transmitter, and the code length is 256, for example, the number of chips N per symbol. 8b is a multiplier for multiplying the Ich signal and the spreading code for each chip, 8b 'is a multiplier for multiplying the Qch signal and the spreading code for each chip, and 8c and 8c' are for integrating the multiplication results over one symbol period (256 8d and 8d 'are adders, 8e and 8e' are one-chip time delay circuits, and 8f and 8f 'are symbol clocks and latch the accumulation result of one symbol period to obtain I symbol data D. _This is an output register for outputting _I 'and _DQ '.

In summary, when the path control is independently performed by the receiver, the correlation value between the received signal and the desired signal (spread code sequence to be predicted) is obtained in the matched filter 7a of the path search unit 2e. The path selector 7c selects the one having the larger value, and notifies the time difference to the despreading circuit 5a (FIG. 18). At this time, if the phase modulation is used, the correlation values I and Q
Are individually obtained in quadrature phase, and their powers or sums of squares are compared. In addition, in order to improve the accuracy of the detection timing, usually, values that appear periodically are integrated such as time average. FIG.
In No. 9, three of the large correlation value integrated outputs are despread.

[0011] despreading timing of the despreading circuit 5a in the arrival time t _1, t _2, t ₃ of the three likely path to be detected in this manner, each finger portion 5 _1, 5 _2, 5 ₃ I do. Each despreading circuit 5a generates a despreading code in accordance with the despreading timing thus obtained, and despreads the received data. In the case of phase modulation, the original data is restored by the demodulation circuit 5b from the I and Q symbol data obtained by despreading. After that, from each delay amount, the other two
Are shifted by the delay circuit 5c to align the positions of the restored data. By adding these, a composite signal is obtained. This result is determined as “0” or “1” by a comparator of a data determination unit (not shown), and is used as received data. In some cases, the maximum ratio combining is performed by multiplying the rake combining unit 6 by a reliability corresponding to each reception level and then adding them before combining. As described above, there are a case where the detection of the multipath and the determination of the despread start timing and the delay time are performed by the receiver independently, and a case where the transmitter notifies the receiver. The latter is a case where the base station performs the above-described detection and notifies the mobile station of the information via a control channel or the like.

[0012]

In mobile communications, the environment of one or both of the transceivers changes with time.
The path search unit 2e estimates that the three newly detected paths are the same as the three paths that have been received up to the present time, based on the delay amount and the reception level that change, and determines its own cycle (for example, a frame). Needs to be followed. In addition, a new path with a different delay amount from the three paths that were initially determined (three paths with high reception strength) may become more certain. In such a case, it is necessary to switch the path assignment. Conventional path assignment switching
Arranging multipath signal to its order of magnitude, assigned multipath signal is the maximum path to the first finger 5 _1, multipath signals assigned the second-largest of the path to the second finger 5 _2, multi path signal was intended to allocate a third the size of the path to the third finger 5 _3. However, in such an allocation method, if the amount of delay of a path estimated to be new and likely is small, the other 2
A part of the spreading period sent via one path is missing.

FIG. 22 is an explanatory diagram of data loss that occurs when the path assignment is switched. At the time of the first path assignment switching, the correlation values of the five paths a to e obtained from the matched filter 7a are b>d>e>a> c in order of magnitude. The path selection section 7c selects upper three paths b, d, and e, assign the path b to the first finger portion 5 ₁ assigns the path d to the second finger portion 5 _2, the path e third
Assigned to the finger portion 5 _3. Each finger part 5 ₁ ,
5 _2, 5 ₃ are time T _11, T _12, the T ₁₃ pass b, d, performs inverse diffusion processing on the signals arriving from the e, delays the despread signal obtained time d _1, d _2, d ₃ Delay and align the phase and output.

Next, at the time of the second path assignment switching,
And the five paths a to 5 obtained from the matched filter 7a
The correlation value of e becomes d> b> a> e> c in order of magnitude. Pa
The selection unit 7c selects the top three paths d, b, and a, and
D to the first finger portion 5 ₁And assign path b to
2 fingers 5_TwoAnd assign path a to the third
Nanger part 5_ThreeAssign to As a result, each finger
5₁, 5_Two, 5_ThreeIs the time T_{twenty one}, T_{twenty two}, T_{twenty three}smell
Despreading the signals arriving from paths d, b, and a
And the obtained despread signal is delayed by d₁', D_Two′,
d_Three'Delay and align the phases and output. From the above,
1, via the path b during the second path assignment switching time
If the received valid data is 8 symbols, the path d
Is 6.7 symbols, the path d
The valid data received via is 4.6 symbols.
For this reason, the data from path d
Is missing for 1.3 symbols (missing part DF1), path e
Data is missing for 3.4 symbols (missing part DF
2). In this missing part, the spreading gain decreases and the detection accuracy is poor.
Become

Even if the three probable paths do not change, if the multipath signal level (correlation value) changes, the path assignment is switched and the above-described data loss occurs. Further, depending on the reception environment and the symbol period, more symbols are lost, and in some cases, data from all paths is lost. In the above path search method, finger portions are sequentially assigned starting from the path having the highest reception level. This path allocation method has an advantage that it can be easily performed. However, as described above, data loss occurs, and even in the same three paths, they are interchanged depending on the multipath signal level (correlation value), and data loss occurs due to this interchange. Therefore, it is necessary to estimate the identity of the previous path and the current path, and if they are the same, do not change the assignment of the path to the finger portion. Path estimation includes frequency accuracy of the carrier and clock of the system,
In order to accurately determine the same path from the fading speed, it is necessary to prepare a DLL (Delay Locked Loop) circuit for each path. However, the DLL circuit requires an analog circuit such as an A / D converter and a voltage controlled oscillator VCO for each path, and the reception level of the locked path is equal to or higher than a threshold value depending on the path switching method. Then, there is a problem that the path switching is not performed even if the new path is certain. As described above, conventionally, there has been a problem that data is lost when the path assignment is switched. Further, the method of estimating the identity of a path using a DLL circuit has a problem that the number of analog circuits is increased and that the path assignment cannot be accurately switched.

Accordingly, it is an object of the present invention to provide a rake receiver capable of suppressing data loss.
Another object of the present invention is to provide an A / D converter and a voltage controlled oscillator V
An object of the present invention is to provide a rake receiver that does not require an analog circuit such as CO. Another object of the present invention is to provide a rake receiver that can accurately switch path assignment at an appropriate timing. Another object of the present invention is to provide a rake receiver employing space diversity, which can suppress data loss and can correctly switch path assignment. Another object of the present invention is to enable data loss to be suppressed even when transmission information must be received from two or more base stations during soft handover, and to correctly switch path assignment. Rake receiver.

[0017]

SUMMARY OF THE INVENTION According to the present invention, a desired signal arriving via an assigned path among multipaths is subjected to a despreading process, and a despread signal obtained by the despreading process is obtained. A plurality of despreading / delay adjusting units for adding a delay amount corresponding to the path to the output, a synthesizing unit for synthesizing outputs of the respective despreading / delay adjusting units, and a path search for allocating a path to each despreading / delay adjusting unit In a rake receiver having a section, the path search section includes: (1) a correlation detection section that detects a correlation between a received signal and a desired signal, and outputs a correlation value and a detection time, and (2) a correlation detection section based on the correlation value. And (3) determining whether or not the selected path is the same as the path previously assigned to each despreading / delay adjusting unit. The detection time of the desired signal arriving via the path And a path follower that causes the same despreading / delay adjusting unit to perform the despreading and delay adjusting processing on the desired signal arriving via the selected path if the path is the same. Rake receiver. In this way, if the path previously assigned to the finger part and the path selected this time are the same, the assignment of the path to the finger part is not changed, so that data loss at the time of path assignment can be prevented.

In the present invention, the determination of the path identity is performed as follows. The path following section stores (1) the detection time of the desired signal arriving via the path allocated to each despreading / delay adjusting section in the storage section, and (2) arrives via the path selected this time. It is checked whether the difference between the detection time of the desired signal and the stored detection time is within an allowable range. (3) If the difference is within the allowable range, the path selected this time is subjected to a predetermined despreading / delay adjustment. (4) despreading and delay adjusting the desired signal arriving via the selected path to the same despreading / delay adjusting unit. Let it run. As described above, since the identity of the path is determined based on whether the difference in the detection time is within the allowable range, the accuracy of estimating the path identity can be improved, and the DLL circuit and the like can be eliminated.
Also, by performing despreading according to the latest and most probable path estimation result, a rake receiver with high gain can be realized.
Further, to the despreading / delay adjusting unit for which the path has not been allocated according to the path identity criterion, the paths from which the desired signal having the higher reception level arrives are sequentially allocated. This allows
Each path can be easily assigned to the despreading / delay adjusting unit.

When there are two or more correlation value peaks within the range having the correlation of the spreading code, the path search unit excludes a peak having a small reception level from the path selection target. As a result, an adverse effect due to noise can be removed.
In a rake receiver employing space diversity, the same directivity is added to the condition of path identity. In this way, even in a diversity rake receiver, switching of path assignment can be performed correctly, and data loss can be minimized. Also, in a rake receiver that receives transmission information from two or more base stations at the time of soft handover or the like, it is added that the same transmitting station is included in the path identity condition. If you do this,
Switching of path assignment can be correctly performed at the time of soft handover or the like, and data loss can be minimized.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (A) Outline of the present invention FIG. 1 is a basic configuration diagram of a rake receiver according to the present invention. In the figure, 11 ₁ to 11 ₃ is despread with fingers (despreading / delay adjustment section), three delay desired wave b arriving via the assigned path, d, to e at the timing P ₁ to P ₃ A processing unit for adding delay amounts d _{1 to} d ₃ according to the path to the despread signal obtained by the despreading process and outputting the resultant signal. Reference numeral 12 denotes a synthesis unit that synthesizes the output of each finger unit. A path search unit that allocates a path to the finger unit. The path search unit 13 detects the correlation between the received signal and the desired signal, and outputs a correlation value and a detection time. The correlator 31 outputs a correlation value and a detection time. The selecting unit 32, if the selected path is the same as the path previously assigned to any finger unit,
There is a path following unit 34 that causes the finger unit to perform despreading / delay adjustment processing.

The path follower 34 prepares a pseudo S-curve as a window, like the DLL, for estimating path identity. That is, if there is a newly detected correlation timing within the S-curve window of the previous despread timing, it is estimated that the paths are the same. Specifically, it is determined whether the detection timing (T ₀ ) of the correlation value of the path previously assigned to any of the finger portions and the detection timing (T ₁ ) of the correlation value of the path selected this time are within ± δ chips. to decide. That is, it is checked whether the following equation is satisfied: T ₀ −δ <T ₁ <T ₀ + δ, and if so, it is estimated that the paths are the same. The path following unit 34 individually allocates the selected paths that have not been allocated to the finger units that do not allocate paths based on the above-described path identity. Since these are newly created probable paths, the timing of the previous paths may be significantly different, but the paths with lower reception levels are truncated and the gain due to their combination is small, so the missing The effect is small.

In summary, the path following section 34 determines that the paths selected by the path selecting section 33 are the finger sections 11 ₁ to 11 _1.
1 ₃ whether the same path and which has been assigned to it is performed as follows based on the detected timing of the desired signal arriving via path. That is, the path tracking section 34, the detection timing T ₀ of the desired signal arriving via the path assigned to (1) the finger portions 11 ₁ to 11 ₃
(2) The difference between the detection timing T ₁ of the desired signal arriving via the path selected this time and the stored delay time T ₀ is within an allowable range. −δ
(3) If the difference is within the allowable range, it is determined that the path selected this time is the same as the path previously assigned in the predetermined finger portion, and (4)
A despreading and delay adjustment process for a desired signal arriving via the selected path is executed by the same finger unit as before. In addition, the path following unit 34 sequentially assigns, to the finger units that have not been assigned a path in accordance with the path identity criterion, the paths from which the desired signal having a large correlation value, which has been selected by the path selection unit, arrives. As described above, if the path previously assigned to the finger part and the path selected this time are the same, the assignment of the path to the finger part is not changed, so that data loss at the time of path assignment can be prevented. Further, since the identity of the path is determined based on whether the difference in the delay time is within the allowable range, the accuracy of estimating the path identity can be improved, and the DLL circuit and the like can be eliminated.

FIG. 2 is an explanatory diagram of path assignment. At the time of the first path allocation, the correlation values of the five paths a to g obtained by the correlation detecting unit 31 are b>d>e> c in the order of magnitude.
> A. The path selection unit 33 selects the top three paths b, d, and e with the number of fingers (= 3) as candidate paths, and sends the detection times T ₁ , T ₂ , and T ₃ to the path follower 34 in the order of correlation values. Output. At the initial stage, the path following unit 34 stores the detection times T ₁ , T ₂ , and T ₃ , and sets the paths of the first to third finger units 1 in the order of candidate paths b, d, and e having large correlation values.
Assigned to 1 _1, 11 _2, 11 _3. That is, at the beginning,
Path tracking section 34 assigns the path b to the first finger unit 11 _1, assign the path d to the second finger portion 11 _2, assign the path e to the third finger portion 11 _3, opposite to the respective fingers inputting a spread start timing t ₁ ~t ₃ and the delay time d ₁ to d _3. Each finger part 1
1 _1, 11 _2, 11 ₃ each time t _1, t _2, at t ₃ pass b, d, performs inverse diffusion processing on the signals arriving from the e, delays the despread signal obtained time d _1, d ₂ , and d _{3 are} delayed and the phases are aligned and output.

Next, at the time of the second path allocation,
The correlation values of the five paths a 'to e' obtained by the correlation detection unit 31 are d '>b'> a '>c'> e 'in order of magnitude. The path selection unit 33 selects the top three paths d ', b', a 'having the number of fingers (= 3) as candidate paths, and detects the detection times T ₁ ', T ₂ ', T _{3 in the} order of correlation values. 'To the path follower 34. Thereby, the path following unit 34
Checks whether the difference between the detection time T ₁ ′ of the candidate path d ′ selected this time in the order of the correlation value and the previously stored detection times T _{1 to} T ₃ is within an allowable range, and then, It is checked whether the difference between the detection time T ₂ ′ of the large candidate path b ′ and each of the stored detection times T _{1 to} T ₃ is within an allowable range, and finally, the detection time T ₃ ′ is stored. It is checked whether the difference between each of the detection times T _{1 to} T ₃ is within an allowable range.

If the difference is within the allowable range, the path following section 34 determines that the path selected this time is the same as the path previously assigned to the predetermined finger section. For example,
Since both the difference between the detection time T ₁ and the detection time T ₁ ′ and the difference between the detection time T ₂ and the detection time T ₂ ′ are within the allowable ranges, the path b and the path b ′ and the path d and the path d ′ It is determined that the paths are the same. Next, the path following unit 34 causes the finger units of the paths b and d to execute despreading and delay adjustment processing on the desired signal arriving via the paths b 'and d'. That is, the path tracking section 34 'assigned to the first finger unit 11 _1, the path d' Path b a assigned to the second finger portion 11 _2, starting despreading respective fingers timing t ₁ ', t ₂ 'And the delay time d
₁ ', d _2' to enter. As described above, if the paths b and d are the same as the paths b 'and d' selected this time, the despreading and delay adjustment processing for the desired signal arriving via the paths b 'and d' is performed on the paths b and d. d finger part 11 ₁ , 1
Since subsequently causing at 1 _2, data missing at the finger portions 11 _1, 11 ₂ is not generated at the time of path allocation. Further, since the identity of the path is determined based on whether the difference between the detection times is within an allowable range, the accuracy of estimating the path identity can be improved.

On the other hand, the path following unit 34 determines whether the finger unit 1 that has not been assigned a path in accordance with the path
The 1 _3, 'assigns a despreading start to the finger portion 11 ₃ a timing t _3' path a which has not been allocated in the same manner to enter and the delay time d ₃ '. As a result, despreading and delay adjustment processing to the desired signal fingers 11 ₃ coming therefrom to pass e different path a '. As a result, the data from the path e is lost for 3.4 symbols (missing portion DF), and the spreading gain is reduced by this loss, but the total number of missing data can be minimized, and the detection accuracy is improved as compared with the conventional method. can do.

(B) Rake Receiver of First Embodiment (a) Overall Configuration FIG. 3 is a diagram showing the configuration of a rake receiver according to a first embodiment of the present invention. It is attached. 11 ₁
To 11 ₃ have respective fingers is (despreading / delay adjustment section), based on the timing t ₁ ~t ₃ instructed by the desired signal arriving via the assigned path subjected to despreading processing, despreading processing , And outputs the despread signal obtained by the above by adding delay amounts d _{1 to} d ₃ corresponding to the path.
Is a combining unit that combines the outputs of the finger units, and 13 is a path search unit that assigns a path to each finger unit.

[0028] Each finger portions 11 ₁ to 11 ₃ are made identical configuration, despreading circuit 21, the demodulation circuit 22, a delay circuit 23. Each despreading circuit 21 includes a path search unit 1
Received Ich signal using a spreading code of own channel 3 to the indicated despreading timing (t ₁ ~t _3), despreading processing Qch signals. The demodulation circuit 22 demodulates the original data using the I symbol data D _I and Q symbol data D _Q obtained by the despreading, and the delay circuit 23
The output is delayed with the time (d _{1 to} d ₃ ) specified by ₃ .
As a result, each finger unit 11 ₁ to 11 ₃ despreads a spreading code the same timing as the transmitter, and adjust the delay time in accordance with the path, and enter the RAKE combining unit 12 by aligning phases, Lake The combining unit 12 combines the input signals and outputs the combined signals. The path search unit 13 includes a matched filter (MF) 31 for detecting a correlation, and an integration circuit 3 for integrating and outputting a correlation value.
2. It has a path selecting unit 33, a path following unit 34, and a timing generating unit 35. The matched filter 31 extracts a signal component (a desired signal) of the own channel from the antenna reception signal using the spreading code of the own channel, and outputs the signal component. In this case, since the correlation values I and Q of the Ich signal and the Qch signal can be obtained independently, for example, an operation of (I + jQ) (I−jQ) = I ² + Q ² is performed and output as a power value. . The path selection unit 33 selects a path from which the desired signal of the number of fingers (three in the figure) arrives in the descending order based on the integrated correlation value obtained by integrating the correlation value, and determines the desired signal arriving via the path. The detection time of is output.

The path follower 34 has a path determiner 41 and a path allocator 42. The path determination unit 41 determines whether the path selected by the path selection unit 33 is the same as any of the paths selected up to that time, based on the detection time. If the result of the determination is that the path is the same, the path allocating unit 42 allocates the path so that the same finger unit performs the despreading and delay adjustment processing on the desired signal arriving via the path selected this time. . That is, if the current path and the previous path are the same, the same finger unit is continuously executed to perform the despreading / delay adjustment processing. Further, the path allocating unit 42 forcibly allocates the paths selected in the order of the reception level to the finger units for which the path has not been allocated in accordance with the criterion of the path identity. The timing generation unit 35 includes the respective finger units 11 ₁
To 11 ₃ to the allocated path detection timing T ₁ through T ₃ depending on the despread-start timing data t of each finger portion
It generates a ₁ ~t ₃ and the delay time data d ₁ to d ₃ is input to each finger unit 11 ₁ to 11 _3.

(B) Path selection unit FIG. 4 is a block diagram of the path selection unit.
Correlation value R after integration ₀And its correlation detection timing (scan
Lot counter value) T₀Is input, and the eight
Correlation value R₁~ R₈And its detection time T₁~ T₈What sorts
It is. It should be noted that selecting eight pieces means eight fingers.
Part is assumed to exist. In FIG.₁~
33₈Is the first to eighth largest integrated correlation value R₁~ R₈Passing
And its detection time T₁~ T₈Is a circuit for storing
The comparator 33a and the D-type FF have the same configuration.
Register 33b and a selector 33c. Comparison
The detector 33a receives the integrated correlation value R_i-1(I = 1-8)
And the integral correlation value R stored in the register_i(I = 1 ~
8) Compare the magnitude of_i-1> R_iIf high-level
It outputs an enable signal ENS. The selector 33c is R
_i-1> R_iIf so, the integration stored in the register 33b
Correlation value R_iAnd detection time T_iIs selected and output to the next stage, and R
_i-1≤R_iIf so, the input integral correlation value R_i-1And its detection
Time T_i-1Is selected and output to the next stage. Register 33b
Is R_i-1> R_iIf so, the input integral correlation value R_i-1And its
Detection time T_i-1Is newly stored and R_i-1≤R_iIf it is
Do not change the contents. As described above, the pass selection unit 33 is large.
8 correlation values R₁~ R₈And its detection time T₁~ T₈
In turn for each circuit 33₁~ 33₈In the register 33b of
Detection time T₁~ T₈Is output to the path follower 34 at the next stage.

(C) Path Follower FIG. 5 is a block diagram of the path follower, and FIG. 6 is a time chart for explaining the operation of the path follower. Numeral 34a denotes an 8 * binary counter, which is composed of an octal counter for counting 0 to 7 and a binary counter for counting overflow pulses and outputting WRITE / READ signals, respectively. 34b is
At the time of WRITE (at the time of pass identity determination) and at the time of READ (at the time of forced path allocation), the first to eighth detection times T are calculated based on the count values 0 to 7.
Selector for outputting the ₁ through T ₈ are sequentially selected and, 41 ₁ to 41 ₈
Are provided corresponding to the first to eighth finger units, and the first to eighth path identity determination units 42 for determining the identity of the current and previous selection paths are assigned based on the path identity determination. This is a path allocating unit that forcibly allocates a path to the missing finger unit.

The path identity determination section The first to eighth path identity determination sections 41 _{1 to} 41 ₈ have the same configuration, a storage section 41a for storing the previous detection timing Tj ', and a current output from the selector 34b. Is compared with the previous detection timing Tj ', and the following equation Tj'-. Delta. <Ti <Tj '+. Delta. (J = 1 to 8) (1) where it is checked whether δ = 2 chips is satisfied. The device 41b and the AND gate 41c, and an OR gate 41d for outputting an enable signal Ei when the above expression is satisfied and when a forced capture pulse Pi described later is generated. WRITE time (path identity determination time), the selector 34 outputs the i-th detection time Ti corresponding to the count value i, comparison section 41b and the AND gate 41c of each path identity determining unit 41 ₁ to 41 ₈ (1 ) Check if the expression is satisfied. If the above expression is satisfied, it is estimated that the path at the detection time Ti is the same as the path previously assigned to the j-th finger unit. For example, in the i detection time Ti of the current first pass identity determining unit 41 _1, to satisfy the expression (1) (j = 1), first pass the identity determining unit 41 ₁ is the detection time Ti Is stored in the storage unit 41a. Further, the first path identity determination unit 41 ₁ inputs the detection time Ti to the timing generation circuit 35 (FIG. 3) as the detection timing of the path assigned to the first finger unit.

The path allocator 42 includes an OR gate 42a, a RAM 42
b, a path assignment finger storage unit 42c, and a priority determination circuit 42d. The OR gate 42a includes first to eighth
Calculates the OR of the enable signals E ₁ to E ₈ to output from the path identity determining unit 41 ₁ to 41 ₈ and outputs. That is, the OR gate 42a outputs a high-level signal when it is determined that the paths are the same by the path identity determination. RA
M42b is when WRITE is enabled (when path identity is determined)
The OR gate output is written to the address indicated by the count values 0 to 7 of the counter 34a, and the RAM indicated by the count values 0 to 7 of the counter 34a when READ is enabled (when the path is forcibly assigned).
Reads and outputs data from the address. That is,
RAM42b has a first to a storage area corresponding to the eighth detection time T ₁ through T _8, writes "1" in the storage area corresponding to the detection time of the path assigned during the path identity determination, path forced At the time of allocation, storage contents are sequentially output from each storage area.

The path assignment finger storage section 42c stores the first
To the eighth finger unit, and stores “1” in the storage region corresponding to the finger unit to which the path is assigned. That is, when a path is assigned to the i-th finger unit by the path identity determination, a high-level enable signal Ei is output, so "1" is stored in a storage area corresponding to the i-th finger unit. When a path is assigned to the j-th finger unit by forced path assignment, a high-level enable signal Ej is output, so that “1” is stored in a storage area corresponding to the j-th finger unit. Priority determination circuit 42d
Is forcibly assigning a path that has not been assigned by the path identity determination to a finger that has not been similarly assigned. That is, the detection time (pass) that is not allocated is determined from the storage content of the RAM 42b,
The finger unit to which the path has not been allocated is determined from the storage content of the storage unit 42c, and the time (path) not allocated to the finger unit is allocated.

At the time of READ (at the time of forced path assignment), the priority determination circuit 42d sets the RAM 4 indicated by the count value i of the counter 34a.
It is checked whether the path corresponding to the i-th detection time Ti has been assigned to any of the finger portions by the path identity determination with reference to the storage content of 2b. If not assigned, finger units to which no path is assigned are obtained in ascending order of numbers with reference to the storage unit 42. If the j-th finger unit is not assigned a path, the priority determination circuit 42d outputs the j-th path identity determination unit 41 corresponding to the j-th finger unit.
The forced capture signal Pj is output to j. In parallel with the above, the selector 34 outputs the i-th detection time Ti according to the count value i. As a result, the OR gate 41d of the j-th finger portion
, An enable signal Ej is generated, and the j-th path identity determination unit 41j stores the detection time Ti in the storage unit 41a. or,
The j-th path identity determination unit 41j inputs the detection time Ti to the timing generation circuit 35 (FIG. 3) as the detection timing of the path assigned to the j-th finger unit. Further, the path assignment finger storage section 42c stores the high-level enable signal Ej in the storage area corresponding to the j-th finger section.
1 "is stored. Thereafter, the same processing is performed to perform path forced assignment.

(C) Rake receiver of the second embodiment If there is an interval exceeding one chip before and after between adjacent signals,
The correlator can output a more significant correlation than each signal.
=> There is correlation in the spreading code used for DS-CDMA
The range is 1 chip before and after the rectangular wave,
When using a limiting filter,
Spreads several times from plus number +%. However, as shown in FIG.
If the signal interval is within one chip, the correlator
And outputs a correlation value obtained by combining. The combined correlation value is 1
Multiple peak PK in chip range ₁, PK_TwoWhere there is
Maximum peak PK₁Assign to the finger part
Is valid, but smaller peak PK
_TwoIs the other peak PK with more delay difference_ThreeThan combining
Cannot be determined only by the correlation value to determine whether or not is valid. this
Is actually the peak PK as shown in FIG._ThreeSmaller pi
PK_TwoIs the peak PK ₁PK due to the effect of_ThreeBigger
This is because it may be getting worse. Also within the chip range
Since there is also a correlation in noise,
Is the expected gain not obtained because the noise components are not canceled?
It is. Therefore, the peak that takes the maximum value in this one chip range
PK₁Is the only peak that is not the largest peak
PK_TwoAre excluded from pass selection.

FIG. 8 is a block diagram of the second embodiment in consideration of the above, and the same parts as those in the first embodiment of FIG. 3 are denoted by the same reference numerals. The second embodiment differs from the first embodiment in that a mask control unit 36 is provided in the path search unit 13. The mask control unit 36 selects only peaks having the maximum value in one chip range as candidates for path selection, masks non-maximum peaks and excludes them from path selection. Mask control unit 3
6, as shown in FIG. 9, adapted to operate at 4 times the frequency of the chip rate, a peak detector 36 _1, the maximum peak detector 36 _2, 4 binary counter (timer) 36 ₃ I have. In the peak detecting section 36 ₁ , the storage section 36 a
Stores the sampled correlation value after integration,
6b compares the current sampling value with the previous sampling value, outputs a high-level signal when the current sampling value is large, the D-type flip-flop 36c stores the comparator output, and the AND gate 36d decreases from the increase. The peak detection signal PD is output at the time when the signal turns small. In the maximum peak detector 36 _2, 36e are first storage unit for storing the maximum peak in the chip, 36f compares the maximum peak and the magnitude of the detected peak until then, the maximum peak detection signal the larger the current peak The MPD is output, and the AND gate 36g outputs the extreme value detection signal PKDT when the maximum peak detection signal MPD is generated, and stores the value stored in the storage unit 36a as the maximum peak value in the storage unit 36e. Quaternary counter 36 ₃ resets each time the maximum peaks are detected, the next one chip period data valid signal at a timing of the count value 3 to be detected with maximum peak new (the range with a correlation) (Mask Signal) MSK is output, and peaks other than the maximum peak are masked. The path selection unit 33 selects the largest peak within one chip period and performs path selection control. That is, only peaks having the maximum value in the one-chip range are set as path selection candidates, and non-maximum peaks are excluded from path selection.

(D) Rake Receiver of Third Embodiment Although the first embodiment does not consider spatial diversity,
It can be configured to be able to cope with space diversity. FIG. 10 is a configuration diagram of a rake receiver according to a third embodiment which can be applied to a case where two receiving antennas (branch A and branch B) having different directivity directions are provided. Is attached. In the first embodiment, the desired signals are independently despread and delayed by taking only the time axis into account, and the signals are combined. In the third embodiment, the space is further treated as an independent dimension. In FIG.
The points different from the first embodiment shown in FIG.

The matched filters 31A, 31B and the integrating circuits 32A, 31A provided in the branches A and B, respectively.
32B calculates a correlation between each antenna reception signal and a desired wave, and inputs the integrated value to the path selection unit 33. The path selection unit 33 selects a path from which the three desired signals arrive in descending order based on the respective integrated correlation values output from the integration circuits 32A and 32B, and detects a detection time of the desired signal arriving via the paths. , Output the branch to which the path belongs. The path following unit 34 determines that the detection time difference is equal to or less than the allowable value,
When the branches are the same, it is determined that the paths are the same. The timing generation circuit 35 includes the respective finger units 111 to ₁
Detection time of the path assigned to 11 ₃ and based on the branch Field of the path, the branch selection signal B ₁ .about.B _3, the timing signal t ₁ ~t _3, and outputs a delay amount signal d ₁ to d _3. The selector 24, which is provided to the input portion of each finger portion 11 ₁ to 11 _3, the branch selection signal B ₁ .about.B ₃ Ich signals from the branch to instruction, and outputs takes in the Qch signals.

FIG. 11 is a block diagram of the path selection unit of the third embodiment, which has almost the same configuration as the path selection unit of the first embodiment of FIG. The difference is that the first to eighth circuits 33 ₁
To 33 ₈ registers 33b in addition to the integrated correlation values R ₁ to R ₈ and its detection time T ₁ through T ₈ larger in the first to eighth,
The point is that the branch information Br indicating the branch type (branch A, B) of the path is stored, and the detection time and the detected branch are output. FIG. 12 is a configuration diagram of the path follower of the third embodiment, and has almost the same configuration as the path follower of the first embodiment of FIG. The difference is that the storage unit 41e that stores the branch information Br of the path previously allocated to the first to eighth finger units and the comparator 41f that compares the previous branch information with the current branch information include a path identity determination unit 41. point provided on _{1-41 8,} the aND gate 41c, and satisfying the expression (1), and in that outputs an enable signal E ₁ to E ₈ indicating that the path when the branch is the same are the same .

FIG. 13 is an explanatory diagram of path assignment according to the third embodiment. At the time of the first path allocation, the three highest-order paths having a large correlation value are the path b of the branch A and the paths i and g of the branch B in this order. The pass selection unit 33
The paths b, i, and g are selected, and their detection times and branch information are input to the path follower 34. Initial time, path tracking section 34 pass b, i, stores the respective detection times and branch information g, a large path b correlation value, i, the first to third fingers 11 ₁ path in the order of g, 11 ₂ , 11 ₃
Assign to At the time of the second path allocation, the top three paths having the largest correlation value are the path d 'of the branch A and the paths g' and i 'of the branch B in this order. The path selection unit 33 selects these three high-order paths d ', g', and i ', and inputs the detection time and branch information to the path follow-up unit 34. The path following unit 34 selects each path d ′ selected this time,
g ′, i ′ detection time and each path b, i, g selected last time
It is checked whether the difference from the detection time is within an allowable range and the branch is the same.

If the difference is within the allowable range and the branch is the same, the path following section 34 determines that the path selected this time is the same as the path previously assigned in the predetermined finger section. For example, it is determined that the paths g and g 'and the paths i and i' are the same path.
Next, the path following unit 34 causes the finger units 11 ₂ and 11 ₃ of the paths g and i to perform despreading and delay adjustment processing on the desired signal arriving via the paths g ′ and i ′. On the other hand, path tracking section 34 assigns the fingers 11 ₁ path allocation is not similarly path allocation path d 'which has not been made according to the same criteria of a path, the finger units 11 ₁ and path b so far Different path d '
The despreading and delay adjustment processing is performed on the desired signal arriving from. As described above, in a rake receiver employing spatial diversity, since the same directivity is added to the condition of path identity, even in a diversity rake receiver, it is possible to correctly perform switching of path assignment. Data loss can be minimized.

(E) Rake Receiver of Fourth Embodiment Although the first embodiment does not consider simultaneous communication with two base stations, it is necessary to simultaneously communicate with two or more base stations during soft handover. . FIG. 14 is a configuration diagram of a rake receiver according to a fourth embodiment applicable to a case where two or more base stations are simultaneously communicated, and the same parts as those in the first embodiment are denoted by the same reference numerals. The difference from the first embodiment shown in FIG. 3 is that the station setting unit 37 provided in the path search unit 13 inputs the spreading code corresponding to the partner transmitting station (base station) to be received to the matched filter 31. And the point that the station identification information is input to the path selection unit 33, the matched filter 31 calculates the correlation between the signal received from each base station and the desired wave, and the path selection unit 33 receives the input from the integration circuit 32. Based on the integrated correlation value, the three paths are selected in descending order, the detection time of a desired signal arriving via the path and the station identification information BS to which the path belongs are output. The detection time difference is less than the tolerance,
Further, when the station identification information is the same, the path is determined to be the same.

[0044] Figure 15 is a block diagram of the path selection section 33 of the fourth embodiment, differs from the path selection section of the third embodiment (FIG. 11), first to eighth circuits 33 _to 333 ₈ Is that the station identification information BS is stored instead of the branch information Br, and the detection time and the station identification information are output. FIG. 16 is a configuration diagram of the path follower of the fourth embodiment, and has almost the same configuration as the path follower of the third embodiment of FIG. The difference is that the path identity determining units 41 _{1 to} 41 ₈ store the station identification information BS instead of the branch information Br in the storage unit 41 e ′.
And the point that a comparator 41f 'for comparing the previous station identification information with the current station identification information is provided.
(1) satisfies the formula, and the station identification information is in that outputs an enable signal E ₁ to E ₈ indicating that the path is the same when the same.

FIG. 17 is an explanatory diagram of path assignment according to the fourth embodiment. At the time of the first path assignment, the three highest-order paths having a large correlation value are the path b from the station A, and the paths i and g from the station B in this order. The path selection unit 33 selects these three high-order paths b, i, and g, and inputs the detection time and the station identification information BS to the path following unit 34. At the initial stage, the path following unit 34 detects the respective detection times of the paths b, i, and g and the station identification information BS.
Are stored, and the paths are arranged in the order of the paths b, i, and g having a large correlation value in the order of the first to third finger sections 11 ₁ , 11 ₂ , 11 _3.
Assign to At the time of the second path allocation, the top three paths having the largest correlation values are the path d 'from the station A and the paths g' and i 'from the station B in this order. The path selecting unit 33 selects these three upper paths d ', g', and i ', and inputs the detection time and the station identification information BS to the path following unit 34.
The path following unit 34 selects each of the paths d ′, g ′,
It is checked whether the difference between the detection time of i 'and the detection times of the previously selected paths b, i, and g is within an allowable range and the station identification information is the same.

If the difference is within the allowable range and the station identification is the same, the path following section 34 determines that the path selected this time is the same as the path previously assigned in the predetermined finger section. For example, it is determined that the paths g and g 'and the paths i and i' are the same path. Next, the path following unit 34 causes the finger units 11 ₂ and 11 ₃ of the paths g and i to perform despreading and delay adjustment processing on the desired signal arriving via the paths g ′ and i ′. On the other hand, path tracking section 34 assigns the fingers 11 ₁ path allocation is not similarly path allocation path d 'which has not been made according to the same criteria of a path, the finger units 11 ₁ and path b so far Different path d '
The despreading and delay adjustment processing is performed on the desired signal arriving from. As described above, 2 during soft handover
In the rake receiver that receives the transmission information from the base station described above, the fact that the transmitting station is the same is added to the condition of the path identity, so that the path assignment can be correctly switched at the time of soft handover or the like. In addition, data loss can be minimized. As described above, the present invention has been described with reference to the embodiments. However, the present invention can be variously modified in accordance with the gist of the present invention described in the claims, and the present invention does not exclude these.

[0047]

As described above, according to the present invention, if the path previously assigned to the finger part is the same as the path selected this time, the assignment of the path to the finger part is not changed, so that data loss at the time of path assignment is lost. Can be prevented.
Further, according to the present invention, the path identity is determined based on whether the difference in delay time is within an allowable range, so that the accuracy of estimating the path identity can be improved, and the DLL circuit and the like can be eliminated. . Also, by performing despreading according to the latest and most probable path estimation result, a rake receiver with high gain can be realized. Further, according to the present invention, a path from which a desired signal having a high reception level arrives can be allocated to a finger portion to which no path has been allocated in accordance with the path identity criterion, thereby improving the gain.

Further, according to the present invention, when there are two or more correlation value peaks within the range having the correlation of the spreading code, the smaller peaks are excluded from the path selection target. The adverse effects can be eliminated. Further, according to the present invention, in a rake receiver employing spatial diversity, the fact that the directivity direction is the same as the condition of path identity is added, so that even in a diversity rake receiver, switching of path assignment is correctly performed. Data loss can be minimized. Also, according to the present invention, in a rake receiver that receives transmission information from two or more base stations at the time of soft handover or the like, the fact that the transmitting station is the same is added to the condition of path identity,
Switching of path assignment can be correctly performed at the time of soft handover or the like, and data loss can be minimized.

[Brief description of the drawings]

FIG. 1 is a basic configuration diagram of a rake receiver according to the present invention.

FIG. 2 is an explanatory diagram of path assignment according to the present invention.

FIG. 3 is a configuration diagram of a rake receiver according to the first embodiment.

FIG. 4 is a configuration diagram of a path selection unit.

FIG. 5 is a configuration diagram of a path following unit.

FIG. 6 is a time chart for explaining the operation of the path following unit.

FIG. 7 is an explanatory diagram of a second embodiment.

FIG. 8 is a configuration diagram of a rake receiver according to a second embodiment.

FIG. 9 is a configuration diagram of a mask control unit.

FIG. 10 is a configuration diagram of a rake receiver according to a third embodiment.

FIG. 11 is a configuration diagram of a path selection unit according to a third embodiment.

FIG. 12 is a configuration diagram of a path following unit according to a third embodiment.

FIG. 13 is an explanatory diagram of path assignment according to the third embodiment.

FIG. 14 is a configuration diagram of a rake receiver according to a fourth embodiment.

FIG. 15 is a configuration diagram of a path selection unit according to a fourth embodiment.

FIG. 16 is a configuration diagram of a path following unit according to a fourth embodiment.

FIG. 17 is an explanatory diagram of path assignment according to the fourth embodiment.

FIG. 18 is a configuration diagram of a wireless device.

FIG. 19 is a configuration diagram of a path search unit and a rake combining / demodulating unit.

FIG. 20 is an explanatory diagram of a path search in a path search unit.

FIG. 21 is an example of a despreading circuit.

FIG. 22 is an explanatory diagram of data loss that occurs at the time of switching path assignment.

[Explanation of symbols]

11 _{1 to} 11 ₃ ··· Finger unit (despreading / delay adjustment unit) 12 ··· Synthesis unit 13 ··· Path search unit 31 ··· Correlator (matched filter) 32 ··· Path selection unit 33 ··· Path following unit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5K022 EE02 EE31 EE35 5K052 AA11 BB02 CC06 DD03 EE38 FF05 FF29 GG19 GG20 GG42 5K059 CC00 CC07 DD31 DD35 EE02 5K067 AA02 AA33 CC10 CC24 JJ00

Claims (10)

[Claims] 1. A despreading process is performed on a desired signal arriving via an assigned path among multipaths, and a despread signal obtained by the despreading process is added with a delay amount according to the path and output. Multiple despreading / delay adjustment units, each despreading /
In a rake receiver including a combining unit that combines outputs of the delay adjusting unit and a path search unit that assigns a path to each despreading / delay adjusting unit, the path search unit detects a correlation between a received signal and a desired signal. A correlation detection unit that outputs a correlation value and a detection time, a path selection unit that selects a plurality of paths from which a desired signal to be despread based on the correlation value arrives, and the selected path is sent to each despreading / delay adjustment unit. Is determined based on the detection time of the desired signal arriving via the path, and if the path is the same, the inverse of the desired signal arriving via the selected path is determined. A rake receiver, comprising: a path follower that causes the same despread / delay adjuster to perform spread and delay adjust processing. 2. The path following unit determines whether the selected path is the same as the previously selected path based on the detection time of a desired signal arriving via the path. A determination unit, if the same path, a path allocation unit that allocates a path so that the same despreading / delay adjusting unit performs despreading and delay adjusting processing on a desired signal arriving via the selected path. A rake receiver comprising: 3. A path determination unit, comprising: storage means for storing a detection time of a desired signal arriving via a path allocated to each despreading / delay adjusting unit; If the difference between the detection time and the detection time previously stored in the storage means is within an allowable range, it is determined that the path selected this time is the same as the path previously selected in the predetermined despreading / delay adjusting unit. 3. A method according to claim 2, further comprising:
Rake receiver as described. 4. The apparatus according to claim 1, wherein the path allocating unit has means for allocating a path from which a desired signal having a large correlation value arrives to a despreading / delay adjusting unit that has not yet allocated a path according to the same path criterion. 3. The rake receiver according to claim 2, wherein: 5. A peak exclusion means for, when two or more correlation value peaks exist within a range having correlation of a spreading code, excluding a peak having a low reception level from a path selection target, The rake receiver according to claim 1, comprising: 6. The peak elimination means includes: a peak detection unit that detects a peak of a correlation value; a maximum peak detection unit that detects a maximum peak; a maximum peak storage unit that stores a maximum peak; Check whether a larger peak occurs in the range having the characteristic, and if not, output the validity of the path according to the maximum peak, and if it occurs, generate a larger peak in the range having the next correlation 6. The rake receiver according to claim 5, further comprising: a path validity determination unit that checks whether the operation is performed and repeats the same operation. 7. A despreading process is performed on a desired signal arriving via an assigned path among multipaths, and a despread signal obtained by the despreading process is output by adding a delay amount according to the path. Multiple despreading / delay adjustment units, each despreading /
In a rake receiver including a combining unit that combines the outputs of the delay adjusting unit and a path search unit that assigns a path to each despreading / delay adjusting unit, the path search unit includes: A correlation detection unit that detects a correlation value with a desired signal and outputs the correlation value, the detection time thereof, and the directivity direction, and selects a plurality of paths from which the desired signal to be despread arrives based on the correlation value A path selection unit, a path determination unit that determines whether or not the selected path is the same as the previously selected path, based on the directivity direction of the desired signal arriving via the path and the detection time. A path allocating unit that causes the same despreading / delay adjusting unit to execute the despreading and delay adjusting process for the desired signal arriving via the selected path if the path is the same. Leh Receiver. 8. The storage device for storing a detection time of a desired signal arriving via a path allocated to each despreading / delay adjusting unit and a directivity direction of the desired signal. The difference between the detection time of the desired signal arriving via the path and the detection time stored in the storage means is within an allowable range, and the direction of the desired signal arriving via the path selected this time is stored. If there is the same directivity direction, a determination means is provided for determining that the path selected this time is the same as the path previously selected in the predetermined despreading / delay adjusting unit. A rake receiver according to claim 7. 9. A despreading process is performed on a desired signal arriving via an assigned path among multipaths, and a despread signal obtained by the despreading process is added with a delay amount according to the path and output. Multiple despreading / delay adjustment units, each despreading /
In a rake receiver including a combining unit that combines the outputs of the delay adjusting unit and a path search unit that assigns a path to each despreading / delay adjusting unit, the path search unit is configured to combine each received signal received from a different transmitting station with a desired signal. A correlation detector that detects a correlation value with the signal, and outputs the correlation value, the detection time thereof, and the type of the transmitting station, and selects a path from which the desired signal to be despread arrives based on the reception level of the desired signal A path selection unit, a path determination unit that determines whether the selected path is the same as the previously selected path, based on the detection time and the transmitting station of a desired signal arriving via the path, A path allocating unit that causes the same despreading / delay adjusting unit to execute the despreading and delay adjusting processing for the desired signal arriving via the selected path if the path is the same. Receiver. 10. The path determination unit includes: a storage unit that stores a detection time of a desired signal arriving via a path allocated to each despreading / delay adjustment unit and a transmitting station of the desired signal; The difference between the detection time of the desired signal arriving via the path and the detection time stored in the storage means is within an allowable range, and is stored as the transmitting station of the desired signal arriving via the path selected this time. If a certain transmitting station is the same, determining means is provided for determining that the path selected this time is the same as the path previously selected in the predetermined despreading / delay adjusting unit. A rake receiver according to claim 9.