JP2005026996A - Preamble receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To receive a preamble signal with high accuracy while avoiding erroneous detection upon receiving the preamble signal on a random access channel. <P>SOLUTION: A matched filter 101 generates a delay profile for each known signature from the received preamble signal, and a path detecting part 103 detects a maximum correlation value and a phase of a path having the maximum correlation value from the generated delay profile. A threshold determining part 105 compares the detected maximum correlation value with a specified threshold for determination, and an inversely diffusing part 109 multiplies the received preamble signal by a signature having the maximum correlation value with the detected phase of the path to perform inverse diffusion. A hard deciding part 111 performs hard decision of a result of the inverse diffusion. A preamble detecting part 107 uses a decision result of the threshold determining part 105 and a decision result of the hard deciding part 111 to determine the detection of a preamble signal. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
The present invention relates to a preamble receiver.
[0002]
[Prior art]
In the third generation mobile communication system, a code division multiple access (CDMA) method is adopted as a radio access method, and a random access method is described in TS25.211 and TS25.213 of 3GPP (Third Generation Partnership Project). .
[0003]
According to 3GPP TS25.211 and TS25.213, a mobile station uses a random access channel (RACH) to establish a connection with a base station before transmitting a message. A preamble signal as a signal is transmitted to the base station.
[0004]
When the preamble signal is normally received at the base station, the response signal is transmitted from the base station. On the other hand, the mobile station retransmits the preamble signal while increasing the transmission power until the response signal can be received. The base station transmits a response signal, and then waits for a message signal from the mobile station at a predetermined timing.
[0005]
Since the base station receives a preamble which is a random access signal from a plurality of mobile stations on such a random access channel, it is as much as possible that the preambles from different mobile stations collide on the random access channel. It is necessary to avoid it.
[0006]
As a method for this, 3GPP introduces access slotting and signatures for separating preamble signals from a plurality of mobile stations in order to disperse the timing at which mobile stations perform random access.
[0007]
FIG. 9 shows an example of the configuration of a preamble signal in which a signature is introduced. As shown in FIG. 9, the signature has a length of 16 chips (S0 to S15), and a preamble signal having a length of 4096 chips is configured by repeating the 16-chip cycle 256 times. In 3GPP, 16 types of signatures are defined, and each has an orthogonal property. Therefore, as a result, there are 16 types of preamble signals.
[0008]
In the mobile station, the types of signatures that can be used are determined in advance, and one type of signature is selected at random from the range of signatures that can be used in the cell, and a preamble signal is transmitted. Further, when receiving the preamble signal, the base station detects the preamble signal corresponding to the used signature for each access slot in parallel, so that the preamble signals of different signatures can be separated.
[0009]
As an example of such a preamble receiver, for example, the one described in Patent Document 1 is known.
[0010]
FIG. 10 is a block diagram showing a main part configuration of a conventional preamble receiving apparatus 1. In the preamble receiver 1 shown in FIG. 10, the signal power to interference power ratio is calculated from the received preamble signal using the matched filter 3, the path detection unit 5, and the RAKE combining unit 7, and the calculated signal power pair is calculated. The interference power ratio is compared with a predetermined threshold by the preamble detector 9.
[0011]
Then, the determination result obtained by comparison is output to the CPU 11. The CPU 11 controls to transmit an AICH (Acquisition Indication Channel) that is a response signal when the calculated signal power to interference power ratio is equal to or greater than the threshold value. Controls not to send.
[0012]
As described above, in the preamble receiver 1, the preamble detector 9 determines the RAKE combining result after path detection, that is, the determination as to whether or not the threshold is exceeded, and reduces the probability of missing the detection of the preamble signal.
[0013]
[Patent Document 1]
JP 2001-204072 A
[0014]
[Problems to be solved by the invention]
However, in the conventional preamble receiving apparatus 1, the preamble detection unit 9 determines whether or not the preamble signal has been received by determining whether or not the RAKE combining result after path detection exceeds the threshold value. When the threshold value is set low in order to maintain the performance, there is a high possibility that the preamble signal is erroneously detected, AICH is transmitted unnecessarily, and the amount of interference increases.
[0015]
In order to prevent erroneous detection of the preamble, it is conceivable that the threshold value is set high. However, when the RAKE synthesis result is compared with a high threshold value, the probability that the preamble signal is missed increases, and the preamble reception performance deteriorates. There was a problem that.
[0016]
The present invention has been made in view of the above points, and provides a preamble receiver capable of receiving a preamble signal with high accuracy while avoiding erroneous detection when receiving a preamble signal on a random access channel. Objective.
[0017]
[Means for Solving the Problems]
The preamble receiver of the present invention is generated by delay profile generation means for generating a delay profile for each known signature by performing a correlation operation while shifting a plurality of known signatures to a received preamble signal composed of a predetermined signature. A maximum correlation value, a detection means for detecting a phase of a path having the maximum correlation value, and a threshold determination means for comparing the detected maximum correlation value with a prescribed threshold value, from a delay profile of the obtained signature; Based on the detected phase of the path, the received preamble signal is despread by multiplying the detected signature having the maximum correlation value, and the result of despreading by the despreading unit is hard-decisioned Using the hard decision means, the decision result of the threshold decision means and the decision result of the hard decision means, the reception preamble A configuration and a preamble detection means for determining the detection signal.
[0018]
According to this configuration, the phase of the path having the maximum correlation value and the maximum correlation value is detected from the delay profile of the known signature generated using the received preamble signal, and threshold determination is performed using the detected maximum correlation value. At the same time, the received preamble signal is despread with a signature having the detected maximum correlation value with the detected phase of the path, integration processing is performed, and the detection result of the received preamble signal is determined by making a hard decision on the result of the integration processing. Therefore, the detection accuracy of the received preamble signal can be improved and the false detection rate can be reduced.
[0019]
The preamble receiver of the present invention performs a correlation operation on a received preamble signal obtained by spreading a predetermined signature with a spreading code while shifting the spreading code and a plurality of known signatures to obtain a delay profile for each known signature. A delay profile generating means for generating, a detecting means for detecting a maximum correlation value and a phase of a path having the maximum correlation value from the generated delay profile, and a threshold value for defining the detected maximum correlation value Threshold determination means for comparison, despreading means for multiplying a known spreading code by the detected phase of the path and despreading, and multiplying the despreading result output from the despreading means by a known signature A signature collating unit that collates the despreading result with the known signature, and a determination result of the threshold value determining unit. And using the matching result of the signature verification unit, a configuration having a preamble detecting means for determining the detection of the received preamble signal.
[0020]
According to this configuration, the phase of the path having the maximum correlation value and the maximum correlation value is detected from the delay profile of the known signature generated using the received preamble signal, and threshold determination is performed using the detected maximum correlation value. In addition, the detection accuracy of the received preamble signal is improved by determining the detection of the received preamble signal by collating the despread result obtained by despreading the known reverse calculation code with the phase of the detected path with the known signature. And the false detection rate can be reduced.
[0021]
The preamble reception apparatus of the present invention includes: a delay profile generation unit configured to generate a delay profile of the known signature by performing a correlation operation while shifting a plurality of known signatures to a received preamble signal including a predetermined signature; A path detection that detects a delay profile of the signature having the maximum correlation value from the delay profile and detects correlation values and phases of the top N paths in descending order of the correlation value in the detected delay profile having the maximum correlation value. Means, a correlation value adding means for adding the correlation values of the detected top N paths, a threshold value judging means for comparing and comparing the added correlation value with a prescribed threshold value, and the detected top N numbers Despreading means for despreading the detected signature at each of the phases of the path and the result of despreading RAK RAKE combining means for combining and calculating a correlation result, hard decision means for making a hard decision on the correlation result obtained by RAKE combination, the reception preamble using the decision result of the threshold decision means and the decision result of the hard decision means A configuration having preamble detection means for determining signal detection is adopted.
[0022]
According to this configuration, the delay profile of the signature having the maximum correlation value is detected from the delay profile of the known signature generated using the received preamble signal, and the correlation values of the top N paths in the detected delay profile Is added to the specified threshold value, and the received preamble is determined with a hard decision on the correlation result obtained by despreading the detected signature and RAKE combining with the phase of the correlation value of the top N paths. Since the detection of the signal is determined, the detection accuracy of the received preamble signal can be further improved and the false detection rate can be further reduced.
[0023]
The preamble receiver of the present invention employs a configuration having control means for controlling the operations of the despreading means and the hard decision means using the determination result of the threshold value determination means in the above configuration.
[0024]
According to this configuration, in order to control the operation of the despreading unit and the hard decision unit according to the determination result of the threshold determination unit, the despreading unit and the hard decision are determined when the threshold determination unit determines that there is no received preamble signal. By stopping the operation of the means, the power consumption of the entire preamble receiver can be reduced.
[0025]
The preamble reception apparatus of the present invention employs a configuration having control means for controlling the operations of the despreading means and the signature matching means using the determination result of the threshold value determination means in the above configuration.
[0026]
According to this configuration, in order to control the operation of the despreading unit and the signature verification unit according to the determination result of the threshold determination unit, the despreading unit and the signature verification are performed when the threshold determination unit determines that there is no received preamble signal. By stopping the operation of the means, the power consumption of the entire preamble receiver can be reduced.
[0027]
In the above configuration, the preamble receiving apparatus of the present invention employs a configuration in which the delay profile generation unit includes a holding unit that holds a correlation calculation result in the delay profile.
[0028]
According to this configuration, since the correlation calculation result at the phase in the delay profile is held by the holding means of the delay profile generation means, the correlation calculation result is output to the hard decision means without using the despreading means. Can be determined.
[0029]
In the preamble reception apparatus of the present invention, in the above configuration, the despreading is performed by rearranging signatures repeated in a predetermined cycle in the received preamble signal so as to group the signatures corresponding to the same chip timing from the beginning of each signature. The arrangement further includes rearranging means for outputting to the means.
[0030]
According to this configuration, the rearrangement unit rearranges the received preamble signal into a state in which the signals corresponding to the same chip timing from the head of each signature repeated at a predetermined period are collected. Therefore, the despreading process by the despreading means can be performed quickly.
[0031]
DETAILED DESCRIPTION OF THE INVENTION
The essence of the present invention is to generate a delay profile of a signature having a maximum correlation value generated using a received preamble signal on a random access channel, despread the path phase of the maximum correlation value in the delay profile, and an integration process By making a hard decision on the result, the reception of the preamble signal is determined, the false detection rate is reduced, and the detection accuracy of the received preamble signal is improved.
[0032]
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0033]
(Embodiment 1)
FIG. 1 is a block diagram showing a configuration of preamble reception apparatus 100 according to Embodiment 1 of the present invention.
[0034]
The preamble receiving apparatus 100 detects a received preamble signal (hereinafter referred to as a “preamble received signal”) obtained by spreading a signature having a predetermined length with a common spreading code (scrambling code) from the preamble received signal. By performing despreading with the path phase of the maximum correlation value and making a hard decision on the result of despreading, the detection accuracy when detecting the preamble reception signal is improved and the false detection rate is reduced.
[0035]
As illustrated in FIG. 1, the preamble receiving apparatus 100 includes a matched filter 101, a path detection unit 103, a threshold determination unit 105, a preamble detection unit 107, a despreading unit 109, and a hard determination unit 111.
[0036]
The matched filter 101 performs complex multiplication on the preamble reception signal while shifting a known spreading code and 16 known signatures, calculates a delay profile for each of the 16 signatures, and outputs the delay profile to the path detection unit 103.
[0037]
The path detection unit 103 includes the maximum correlation value in the calculated delay profile, the phase of the path having the maximum correlation value (hereinafter referred to as “maximum correlation value path phase”), the maximum correlation value, and the signature having the maximum correlation value path phase. And the maximum correlation value is output to the threshold value determination unit 105, and the maximum correlation value path phase and the signature having the maximum correlation value and the maximum correlation value path phase are output to the despreading unit 109.
[0038]
The threshold determination unit 105 determines whether or not the detected maximum correlation value exceeds a prescribed threshold, and outputs a determination result to the preamble detection unit 107.
[0039]
The despreading unit 109 converts the input pre-ample received signal into a signature pattern having a known spreading code and a maximum correlation value detected by the path detection unit with the phase of the maximum correlation value path detected by the path detection unit 103. And despreading is performed, and the result of despreading is output to the hard decision unit 111.
[0040]
FIG. 2 is a diagram illustrating a preamble reception signal that is despread by the despreading unit, where FIG. 2A is a preamble reception signal before being input to the despreading unit, and FIG. 2B is a despreading unit. The preamble reception signal in FIG.
[0041]
As shown in FIG. 2B, when the preamble reception signal P1 is input, the despreading unit 109 multiplies the preamble reception signals P1 that are located at the same chip position from the signature head. As a result, the preamble reception signal P1 is despread while each signature pattern is extracted.
[0042]
The hard decision unit 111 calculates the correlation value by performing an integration process on the despread result already calculated using the known signature in the despreading unit 109. If the correlation value is positive, the hard decision unit 111 matches. Hard decision is made to be inconsistent. The hard decision unit 111 can obtain 16 of these results. If the correlation values do not match, they are counted as mismatch bits. This process is performed for each successive signature in the preamble reception signal.
[0043]
Hard decision section 111 determines whether the counted number of mismatch bits exceeds a predetermined error tolerance, and outputs the determination result to preamble detection section 107. The error tolerance value is arbitrarily set by a number from 0 to 16.
[0044]
The preamble detection unit 107 determines that the input threshold determination result exceeds the threshold, and determines the detection of the preamble reception signal only when the hard determination result is determined to be equal to or less than the error tolerance, and the detection result is detected as the preamble detection. Otherwise, the detection result is output as no preamble detected.
[0045]
Next, the operation of preamble reception apparatus 100 having the above configuration will be described.
[0046]
When the preamble receiving apparatus 100 receives a preamble signal from the mobile station side, the preamble received signal is input to the matched filter 101 and the despreading section 109.
[0047]
In the matched filter 101, the preamble reception signal is complex-multiplied by shifting a known spreading code (scrambling code) and 16 known signatures to generate 16 delay profiles. Input to the detection unit 103.
[0048]
The path detection unit 103 detects the maximum correlation value in the delay profile, the phase of the path having the maximum correlation value, and the delay profile of the signature having the maximum correlation value and the path phase. The detected maximum correlation value is output to threshold determination section 105, and the phase and signature of the path having the detected maximum correlation value is output to despreading section 109.
[0049]
The threshold determination unit 105 determines whether or not the input maximum correlation value exceeds a prescribed threshold, and the determination result is output to the preamble detection unit 107.
[0050]
On the other hand, the despreading section 109 multiplies the input preamble reception signal by the known spreading code and the input signature with the maximum correlation value path phase input from the path detection section 103, and performs despreading. Then, the despreading result calculated by the despreading unit 109 is input to the hard decision unit 111.
[0051]
The hard decision unit 111 calculates the correlation value by integrating the input despreading result. Then, in the hard decision unit 111, if the calculated correlation value is positive, the signature of the preamble reception signal and the detected signature match, and if it is negative, a hard decision is made that does not match. Count as a mismatch bit. This process is performed for each bit of the preamble signal (here, for each signature). The hard decision unit 111 determines whether the counted number of mismatch bits exceeds a predetermined error tolerance, and the determination result is output to the preamble detection unit 107.
[0052]
Finally, the preamble detection unit 107 determines that the input threshold determination result exceeds the threshold, and only determines that the hard determination result is equal to or less than the allowable error value, and determines that the preamble is not detected. Output the detection result.
[0053]
As described above, according to the present embodiment, the matched filter 101 generates a delay profile for each of the 16 types of signatures using the preamble reception signal, and the path detection unit 103 determines the maximum correlation from the 16 types of delay profiles. Value, the phase of the path having the maximum correlation value, and the delay profile of the signature having the maximum correlation value, the threshold determination unit 105 performs threshold determination using the detected maximum correlation value, and the despreading unit 109 In the detected path phase, the received preamble signal is despread with the detected signature and integration processing is performed, and the integration processing result is hard-decided by the hard decision unit 111, thereby detecting the received preamble signal. Therefore, the detection accuracy of the received preamble signal can be improved and the false detection rate can be reduced. Kill.
[0054]
(Embodiment 2)
FIG. 3 is a block diagram showing a configuration of preamble reception apparatus 200 according to Embodiment 2 of the present invention.
[0055]
This preamble receiving apparatus 200 improves the detection accuracy in the preamble detecting unit by collating the result of despreading the received preamble signal with the path phase of the maximum correlation value of the received preamble signal with the signature pattern, thereby detecting false detection. The rate is reduced.
[0056]
As illustrated in FIG. 2, the preamble reception apparatus 200 according to the present embodiment includes a matched filter 201, a path detection unit 203, a threshold determination unit 205, a preamble detection unit 207, a despreading unit 209, and a signature pattern matching unit 213. . Note that the matched filter 201, path detection unit 203, and threshold determination unit 205 in the preamble receiver 200 have substantially the same configuration and operational effects as the matched filter 101, path detection unit 103, and threshold determination unit 105 described above. Since it has, explanation is omitted.
[0057]
The despreading unit 209 performs despreading on the input preample received signal by multiplying only the known spreading code by the maximum correlation value path phase detected by the path detection unit 203, and calculates the despread result Is output to the signature pattern matching unit 213.
[0058]
The signature pattern verification unit 213 holds known signature patterns in advance, for example, 16 types of signature patterns. The despreading result inputted from the despreading unit 209, that is, the code of the correlation result, and the code of the known signature pattern Are determined to be “positive” if they match, and “not” if they do not match, and a bit is calculated. Sixteen of these results are obtained.
[0059]
Further, as a result of comparing the code of the correlation result with the code of the known signature pattern, the signature pattern matching unit 213 determines that the preamble has been detected when the number of bits indicating that they match is equal to or less than the error tolerance. If the allowable error value is exceeded, it is determined that the preamble has not been detected, and the collation result is output to the preamble detector 207. The allowable error value can be arbitrarily set from 0 to 16.
[0060]
The preamble detection unit 207 determines that the input threshold determination result exceeds the threshold, and outputs the detection result as preamble detection only when the collation result is determined to be equal to or less than the error tolerance value. Otherwise, the preamble detection is not detected. Output the result.
[0061]
Next, the operation of the preamble receiving apparatus 200 having the above configuration will be described.
[0062]
When the preamble receiving apparatus 200 receives a preamble signal from the mobile station side, the preamble signal (hereinafter, “preamble received signal”) is input to the matched filter 201 and the despreading unit 209.
[0063]
The matched filter 201 generates a delay profile by performing complex multiplication while shifting the preamble reception signal and the known spreading code phase. The generated delay profile is input to the path detection unit 203.
[0064]
In the path detection unit 203, the maximum correlation value and the maximum correlation value path phase in the delay profile are detected, the detected maximum correlation value is output to the threshold determination unit 205, and the detected maximum correlation value path phase is the despreading unit. It is output to 209.
[0065]
The threshold determination unit 205 determines whether or not the input maximum correlation value exceeds a prescribed threshold, and the determination result is output to the preamble detection unit 207.
[0066]
On the other hand, the despreading section 209 multiplies the input preamble reception signal by a known spreading code by the maximum correlation value path phase input from the path detection section 203, and performs despreading.
[0067]
The despreading result calculated by the despreading unit 209 is integrated for each signature pattern and output to the signature pattern matching unit 213 as a correlation result.
[0068]
In the signature pattern matching unit 213, the input correlation result is compared with a plurality of known signature patterns held in advance in the signature pattern matching unit 213, and if the number of matching bits is equal to or less than the error allowable value, the preamble If the error exceeds the allowable error value, it is determined that the preamble has not been detected, and is output to the preamble detection unit 207 as a collation result.
[0069]
Finally, the preamble detection unit 207 determines that the input threshold determination result exceeds the threshold, and only determines that the hard determination result is equal to or less than the error tolerance. Is output.
[0070]
As described above, according to the present embodiment, by performing despreading with the path phase of the maximum correlation value and performing a hard decision on the result of integration processing, the detection accuracy in the preamble detection unit 207 is improved and the false detection rate is reduced. Can be made.
[0071]
Furthermore, when 16 types of signatures are to be detected in parallel, 16 despreading units are required, and the circuit scale is 16 times. In this embodiment, the signature is processed after one despreading unit 209 is processed. Since the pattern matching unit 213 performs processing by collating 16 types of signatures, an effect of reducing the circuit scale can be expected.
[0072]
(Embodiment 3)
FIG. 4 is a block diagram showing a configuration of preamble reception apparatus 300 according to Embodiment 3 of the present invention.
[0073]
Preamble receiving apparatus 300 according to Embodiment 3 of the present invention uses a preamble detection unit that collates with a known signature by multiplying the result of despreading with the phase of the upper N path in descending order of the correlation value and collating with the signature. The detection accuracy is improved and the false detection rate is reduced.
[0074]
Preamble receiving apparatus 300 according to the present embodiment shown in FIG. 4 includes matched filter 301, upper N path detecting section 303, threshold determining section 305, preamble detecting section 307, multiple despreading sections 309, RAKE combining section 311, A hard decision unit 313 is included.
[0075]
The matched filter 301 has the same configuration as the matched filter 101 except that it outputs a delay profile to be generated to the upper N path detection unit 303 instead of the path detection unit 103, and thus description thereof is omitted.
[0076]
The upper N path detection unit 303 calculates the correlation value of the upper N paths and the phase of the path having the correlation value in descending order of correlation values in the delay profile having the maximum correlation value detected by the matched filter 301. To detect.
[0077]
The upper N path detection unit 303 adds the correlation values of the detected upper N paths, outputs the addition result to the threshold determination unit 305, and detects the detected phase and maximum correlation values of the N paths. Are output to N despreading sections 309, respectively.
[0078]
The threshold determination unit 305 determines whether or not there is a preamble signal by comparing the input result of the correlation values for the input N paths with a specified threshold, and if it exceeds the specified threshold, determines whether there is a preamble signal, If it does not exceed, it is determined that there is no preamble signal, and the determination result is output to the preamble detector 307.
[0079]
The despreading unit 309 performs despreading by multiplying each input preamble reception signal by a known spreading code and an inputted signature at each phase of the inputted N paths. Desirably, the despreading unit 309 has a number equal to or greater than the number of upper N paths detected by the upper N path detection unit 303. Here, since N paths are input, N despreading units 309 function.
[0080]
These N despreading units 309 perform the respective despreading processes in parallel, and output these despreading results to the RAKE combining unit 311.
[0081]
The RAKE combining unit 311 integrates the despreading results input from the N despreading units 309 for a certain period of time (for example, 4096 chips which are preamble lengths), and then performs RAKE combining (addition processing), and the hard decision unit It outputs to 313.
[0082]
The hard decision unit 313 performs an integration process on the RAKE-combined despread result to calculate a correlation value, performs a hard decision that matches if the correlation value is positive, and does not match if the correlation value is negative. Is determined to exceed a predetermined error tolerance, and the determination result is output to the preamble detector 307.
[0083]
The preamble detection unit 307 determines that the input threshold determination result has exceeded the threshold, and outputs the detection result as preamble detection only when the hard determination result is determined to be equal to or less than the error tolerance value. Otherwise, the preamble is not detected. Output the detection result.
[0084]
Next, the operation of preamble reception apparatus 300 having the above configuration will be described.
[0085]
When the preamble receiving apparatus 300 receives a preamble signal from the mobile station side, the preamble signal (hereinafter, “preamble received signal”) is input to the matched filter 301 and the despreading unit 309. The matched filter 301 generates a delay profile by performing complex multiplication while shifting the preamble reception signal and the known spreading code phase, and this delay profile is input to the upper N path detection unit 303.
[0086]
The upper N path detection unit 303 detects the correlation values and phases of the upper N paths in the descending order of correlation values in the generated delay profile, and adds the detected correlation values of the N paths to the threshold value. The phase for N paths detected and output to the determination unit 305 is output to the despreading unit 309.
[0087]
The threshold determination unit 305 determines whether or not the addition result of the correlation values for the input N paths exceeds a prescribed threshold, and the determination result is output to the preamble detection unit 307.
[0088]
On the other hand, in the N despreading units 309, despreading is performed by multiplying each received preamble reception signal by a known spreading code and signature at each path phase input from the upper N path detection unit 303 and integrating. Each despreading result performed in parallel and calculated by the despreading unit 309 is output to the RAKE combining unit 311.
[0089]
In the RAKE combining unit 311, the input despreading result is subjected to addition processing (RAKE combining processing) and output to the hard decision unit 313.
[0090]
The hard decision unit 313 calculates a correlation value by integrating the RAKE-combined back calculation result, and performs a hard decision that matches if the calculated correlation value is positive and does not match if the calculated correlation value is negative. When it is determined that there is a mismatch, it is counted as a mismatch bit, and it is determined whether this count exceeds a predetermined error tolerance, and the determination result is output to the preamble detector 307.
[0091]
Finally, the preamble detection unit 307 determines that the input threshold determination result has exceeded the threshold value, and only detects the preamble when the hard determination result is equal to or less than the allowable error value. Otherwise, the preamble detection is not detected. Is output.
[0092]
According to the third embodiment of the present invention, the detection accuracy of the received preamble signal can be further improved, and the false detection rate can be further reduced.
[0093]
In the above configuration, the hard decision unit 313, the despreading unit 309, and the preamble detection unit 307 are replaced with the functions of the signature pattern matching unit 213, the despreading unit 209, and the preamble detection unit 207 of the second embodiment, respectively. It is good.
[0094]
(Embodiment 4)
FIG. 5 is a block diagram showing a configuration of preamble reception apparatus 400 according to Embodiment 4 of the present invention.
[0095]
The fourth embodiment of the present invention includes a rearrangement input unit 409 that rearranges preamble reception data in advance before despreading in the preamble receiving apparatus 100 of the first embodiment. Is simplified.
[0096]
A preamble receiver 400 shown in FIG. 5 includes a matched filter 401, a path detection unit 403, a threshold determination unit 405, a preamble detection unit 407, a rearrangement input unit 409, a despreading unit 411, and a hard determination unit 413.
[0097]
Note that the matched filter 401, path detection unit 403, threshold value determination unit 405, hard decision unit 413, and preamble detection unit 407 in the preamble reception apparatus 400 are the same as the matched filter 101 and path detection unit in the preamble reception apparatus 100 described above. 103, the threshold determination unit 105, the hard determination unit 111, and the preamble detection unit 107 have substantially the same configuration and operational effects, and will not be described.
[0098]
Rearrangement input section 409 rearranges the preamble reception signal input together with matched filter 401 for each signature pattern constituting the preamble reception signal, and outputs the result to despreading section 411.
[0099]
FIG. 6 is a diagram illustrating the preamble reception signals rearranged by the rearrangement input unit.
As shown in FIG. 6, the rearrangement input unit 409 stores 16 chips at the same position from the beginning of the signature in each signature in the preamble reception signal P <b> 1 in which a 16-cycle signature pattern is repeated 256 times. Are rearranged in a state in which they are collected for each signature, and output to the despreading section 411 as a preamble reception signal P2.
[0100]
The despreading unit 411 receives the pre-ample reception signal P2 rearranged for each input signature shown in FIG. 6 with the known spreading code and the input with the maximum correlation value path phase input from the path detection unit 403. The correlation result is calculated by multiplying the signature and performing despreading processing and integration processing. Further, the despreading unit 411 outputs the calculated correlation result to the hard decision unit 413.
[0101]
Next, the operation of preamble reception apparatus 400 having the above configuration will be described.
[0102]
When the preamble receiver 400 receives a preamble signal from the mobile station side, the preamble signal (hereinafter, preamble received signal) is input to the matched filter 401 and the rearrangement input unit 409.
[0103]
The matched filter 401 generates a delay profile by performing complex multiplication while shifting the preamble reception signal and the known spreading code phase. The generated delay profile is input to the path detection unit 403.
[0104]
The path detection unit 403 detects the maximum correlation value and the maximum correlation value path phase in the delay profile, the detected maximum correlation value is output to the threshold determination unit 405, and the detected maximum correlation value path phase is the despreading unit. 411 is output.
[0105]
The threshold determination unit 405 determines whether or not the input maximum correlation value exceeds a specified threshold, and the determination result is output to the preamble detection unit 407.
[0106]
On the other hand, in the rearrangement input unit 409, the received preamble signals are rearranged for each signature pattern and output to the despreading unit 411. In the despreading unit 411, the preamble reception signal rearranged in advance for each signature pattern is multiplied by a known spreading code and signature by the maximum correlation value path phase input from the path detecting unit 403, thereby performing despreading processing. And a correlation result is calculated. In the despreading process in the despreading unit 411, since the signature of the input preamble reception signal is rearranged by the rearrangement input unit 409 so that the despreading process can be easily performed, 16 pieces of target data are skipped. There is no need to extract with, and the processing is faster.
[0107]
The calculated correlation result is input to the hard decision unit 413 and integrated to calculate a correlation value. If the calculated correlation value is positive, the signature of the preamble reception signal and the detected signature are detected. If they match and are negative, a hard decision is made that they do not match. If they do not match, they are counted as mismatch bits. This process is performed for each bit of the preamble reception signal (here, for each signature), and the hard decision unit 413 determines whether the counted number of mismatch bits exceeds a predetermined error tolerance, The determination result is output to the preamble detector 407.
[0108]
Finally, the preamble detection unit 407 determines that the input threshold determination result exceeds the threshold, and only determines that the hard determination result is equal to or less than the allowable error value, and determines that the preamble is not detected. Output the detection result.
[0109]
According to the fourth embodiment of the present invention, the detection accuracy in the preamble detection unit is improved by despreading with the path phase of the maximum correlation value, and the result of integration processing is hard-decision, and the false detection rate is increased. Can be reduced.
[0110]
(Embodiment 5)
FIG. 7 is a block diagram showing a configuration of preamble reception apparatus 500 according to Embodiment 5 of the present invention. The preamble receiving apparatus 500 has a configuration in which a control unit that controls the operation of the despreading unit is provided in the preamble receiving apparatus 100 described above. Therefore, preamble receiving apparatus 500 has the same basic configuration as preamble receiving apparatus 100 corresponding to the first embodiment shown in FIG. 1, and the same components are denoted by the same reference numerals, and the description thereof is omitted. Is omitted.
[0111]
This embodiment is an attempt to reduce the power consumption of the preamble receiver in the first embodiment.
[0112]
A preamble receiving apparatus 500 illustrated in FIG. 7 includes a matched filter 101, a path detection unit 103, a threshold determination unit 505, a preamble detection unit 107, a despreading unit 109, a hard determination unit 111, and a control unit 513.
[0113]
The threshold determination unit 505 receives the maximum correlation value detected from the delay profile from the path detection unit 103, compares the maximum correlation value with a predetermined threshold value, and the maximum correlation value exceeds the predetermined threshold value. And the determination result is output to the preamble detector 107 and the controller 513.
[0114]
The control unit 513 controls the operations of the despreading unit 109 and the hard determination unit 111 based on the determination result input from the threshold determination unit 505. Specifically, when the threshold determination unit 505 determines that the preamble is not detected, the control unit 513 is configured to stop the operations of the despreading unit 109 and the hard determination unit 111.
[0115]
Next, the operation of preamble receiving apparatus 500 having the above configuration will be described. However, only differences from the preamble receiver 100 will be described here.
[0116]
When the preamble receiving apparatus 500 receives a preamble signal (hereinafter, “preamble reception signal”) from the mobile station side, the result determined by the threshold determination unit 505 is output to the preamble detection unit 107 and the control unit 513.
[0117]
In the control unit 513, when the preamble is not detected from the threshold determination unit 505, that is, when the determination result when the maximum correlation value is less than the predetermined threshold is input in the threshold determination unit 505, the despreading unit 109 and the hard determination unit 111 are input. The operation stop control is performed.
[0118]
As described above, according to the present embodiment, when the threshold value determination unit 505 does not exceed the threshold value, it is not necessary to operate the despreading unit and the signature pattern matching unit, so that the power consumption of the entire preamble reception apparatus can be reduced.
[0119]
Note that the preamble receiving apparatus 500 of the present embodiment has attempted to reduce the power consumption of the preamble receiving apparatus 500 itself by providing the control unit 513 in the configuration of the preamble receiving apparatus 100 of the first embodiment. However, the present invention is not limited to this, and any preamble reception apparatus having a hard decision unit and a signature verification unit may be provided in any configuration of the preamble reception apparatus.
[0120]
For example, a control unit is provided in the preamble receiving apparatus 200 of the second embodiment, and this control unit controls the operations of the despreading unit 209 and signature pattern matching unit 213 based on the determination result input from the threshold determination unit 205. The configuration. Specifically, when the threshold determination unit 205 determines that the preamble is not detected, the control unit stops the operations of the despreading unit 209 and the signature pattern matching unit 213. As described above, if the preamble receiving apparatus 200 includes the control unit that controls the operations of the despreading unit 209 and the signature pattern collation unit 213, the despreading unit 209 and the signature pattern collation are performed when the threshold determination unit 205 does not exceed the threshold. Since it is not necessary to operate the unit 213, the power consumption of the entire preamble receiver can be reduced.
[0121]
(Embodiment 6)
FIG. 8 shows a preamble reception apparatus according to Embodiment 6 of the present invention.
[0122]
A preamble receiving apparatus 600 shown in FIG. 8 is an attempt to reduce the hardware circuit scale or software processing load in the preamble receiving apparatus 100. Therefore, it has the same basic configuration as that of the preamplifier receiving apparatus 100 corresponding to the first embodiment shown in FIG. 1, and the same components are denoted by the same reference numerals and description thereof is omitted.
[0123]
The preamble receiving apparatus 600 includes a matched filter 601, a path detection unit 603, a threshold determination unit 105, a preamble detection unit 107, and a hard determination unit 609.
[0124]
The matched filter 601 performs complex multiplication on the preamble signal while shifting a known spreading code and 16 known signatures, calculates a delay profile for each of the 16 signatures, and outputs the delay profile to the path detection unit 603.
[0125]
Also, the matched filter 601 has a memory 601a for accumulating a complex multiplication result at the time of delay profile generation. When the phase of the path having the maximum correlation value is input from the path detection unit 603, the matched filter 601 The multiplication result corresponding to is read from the memory 601 a and output to the hard decision unit 609.
[0126]
The path detection unit 603 detects the maximum correlation value in the calculated delay profile and the phase of the path having the maximum correlation value, and the delay profile of the signature having the maximum correlation value and the phase of the path having the maximum correlation value. The maximum correlation value is detected and output to the threshold determination unit 105, and the phase of the path having the maximum correlation value and the signature are output to the matched filter 601.
[0127]
Next, the operation of preamble reception apparatus 600 having the above configuration will be described. Here, only differences from preamble reception apparatus 100 corresponding to Embodiment 1 will be described.
[0128]
First, when the preamble receiving apparatus 600 receives a preamble signal from the mobile station side, the preamble signal (hereinafter, preamble received signal) is input to the matched filter 601.
[0129]
In the matched filter 601, a preamble signal is complex-multiplied with a known spreading code and 16 known signatures while shifting to generate 16 types of delay profiles, and these delay profiles are input to the path detection unit 603. At the same time, each complex multiplication result when the delay profile is generated is temporarily stored in the memory 601a inside the matched filter.
[0130]
The path detection unit 603 detects and detects the phase delay of the path having the maximum correlation value and the maximum correlation value and the signature delay profile having the maximum correlation value and the path phase in the input delay profile for each signature. The maximum correlation value is output to the threshold determination unit 105, the phase of the path having the detected maximum correlation value is input to the matched filter 601, and the multiplication result of the phase of the path specified from the internal memory 601a is output. And input to the hard decision unit 609.
[0131]
In the hard decision unit 609, as with the hard decision unit 111, integration processing is performed on the input multiplication result, and a correlation value is calculated. If the correlation value is positive, it matches, and if it is negative, it does not match. A hard decision is made. Furthermore, it is determined whether the number of mismatch bits counted as a mismatch bit exceeds a predetermined error tolerance, and the determination result is output to the preamble detection unit 107.
[0132]
As described above, according to the present embodiment, a hardware circuit scale or software processing load of the entire preamble receiver is expected to be reduced by effectively utilizing the processing result performed in the matched filter 601 without newly providing a despreading unit. it can.
[0133]
Note that a base station apparatus including the preamble receiver described in any of Embodiments 1 to 6 can achieve the same effect and improve preamble detection accuracy, so that an AICH is not transmitted unnecessarily. Interference can be suppressed and the number of accommodated channels can be secured.
[0134]
Further, the same effect can be obtained in a mobile communication system including the preamble receiver described in any of Embodiments 1 to 6. In addition, since the preamble detection accuracy is improved, AICH is not transmitted unnecessarily, interference can be suppressed, and the number of accommodated channels can be ensured.
[0135]
Further, it may be stored in a storage medium as an operation program in the preamble receivers of the first to sixth embodiments.
[0136]
【The invention's effect】
As described above, according to the present invention, when a preamble signal on a random access channel is received, the preamble signal can be received with high accuracy while avoiding erroneous detection.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a preamble reception apparatus according to Embodiment 1 of the present invention.
2A is a diagram illustrating a preamble reception signal before being input to a despreading unit, and FIG. 2B is a diagram illustrating a preamble reception signal in the despreading unit.
FIG. 3 is a block diagram showing a configuration of a preamble receiving apparatus according to Embodiment 2 of the present invention.
FIG. 4 is a block diagram showing a configuration of a preamble receiving apparatus according to Embodiment 3 of the present invention.
FIG. 5 is a block diagram showing a configuration of a preamble reception apparatus according to Embodiment 4 of the present invention.
FIG. 6 is a diagram showing preamble reception signals rearranged by the rearrangement input unit;
FIG. 7 is a block diagram showing a configuration of a preamble reception apparatus according to Embodiment 5 of the present invention.
FIG. 8 is a block diagram showing a configuration of a preamble receiving apparatus according to Embodiment 6 of the present invention.
FIG. 9 is a diagram showing an example of the configuration of a preamble signal
FIG. 10 is a block diagram showing a configuration of a conventional preamble receiver.
[Explanation of symbols]
100, 200, 300, 400, 500, 600 Preamble receiver
101, 201, 301, 401, 601 matched filter
103, 203, 403, 603 Path detection unit
105, 205, 305, 405, 505 Threshold determination unit
111, 313, 413, 609 Hard decision part
107, 207, 307, 407 Preamble detector
109, 209, 309, 411 Despreading part
213 Signature pattern verification unit
303 Upper N Path Detection Unit
311 RAKE synthesis unit
409 Sorting input part
513 control unit

Claims (7)

A delay profile generating means for generating a delay profile for each known signature by performing a correlation operation while shifting a plurality of known signatures to a received preamble signal composed of a predetermined signature;
A detection means for detecting a maximum correlation value and a phase of a path having the maximum correlation value from a delay profile of the generated signature;
Threshold determination means for comparing the detected maximum correlation value with a predetermined threshold;
Despreading means for multiplying and despreading the received preamble signal by the detected signature having the maximum correlation value with the detected phase of the path;
Hard decision means for hard decision of the result of despreading by the despreading means;
Preamble detection means for determining detection of the received preamble signal using the determination result of the threshold determination means and the determination result of the hard determination means;
A preamble receiver characterized by comprising: A delay profile generation means for generating a delay profile for each known signature by performing a correlation operation while shifting the spread code and a plurality of known signatures to a received preamble signal obtained by spreading a predetermined signature with a spreading code;
Detecting means for detecting a maximum correlation value and a phase of a path having the maximum correlation value from the generated delay profile;
Threshold determination means for comparing the detected maximum correlation value with a predetermined threshold;
Despreading means for multiplying and despreading a known spreading code by the detected phase of the path;
Signature collating means for collating the despreading result with the known signature by multiplying the despreading result output from the despreading means by a known signature;
Preamble detection means for determining detection of the received preamble signal using the determination result of the threshold value determination means and the verification result of the signature verification means;
A preamble receiver characterized by comprising: A delay profile generating means for generating a delay profile of the known signature by performing a correlation operation while shifting a plurality of known signatures to a received preamble signal composed of a predetermined signature;
From the generated delay profile, the delay profile of the signature having the maximum correlation value is detected, and the correlation values and phases of the top N paths are detected in descending order of the correlation value in the detected delay profile having the maximum correlation value. Path detecting means for
Correlation value addition means for adding the correlation values of the detected top N paths;
Threshold determination means for comparing and determining the added correlation value and a prescribed threshold;
Despreading means for multiplying and despreading the detected signature at each of the detected top N path phases;
RAKE combining means for calculating a correlation result by RAKE combining the despread result;
A hard decision means for making a hard decision on the RAKE-combined correlation result;
Preamble detection means for determining detection of the received preamble signal using the determination result of the threshold determination means and the determination result of the hard determination means;
A preamble receiver characterized by comprising: The preamble reception apparatus according to claim 1, further comprising a control unit that controls operations of the despreading unit and the hard determination unit using a determination result obtained by the threshold determination unit. 3. The preamble receiver according to claim 2, further comprising a control unit that controls operations of the despreading unit and the signature collating unit using a determination result obtained by the threshold determination unit. The preamble receiving apparatus according to claim 1, wherein the delay profile generating means includes holding means for holding a correlation calculation result in the delay profile. Reordering means for rearranging signatures repeated in a predetermined cycle in the received preamble signal so that those corresponding to the same chip timing from the beginning of the respective signatures are collected and output to the despreading means is further provided. The preamble receiver according to claim 1.

Images