JP3843244B2 - Receiving apparatus and receiving method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a receiving apparatus and a receiving method for demodulating a received signal by synthesizing delayed waves.
[0002]
[Prior art]
In IMT2000-TDD, a midamble that is a pilot sequence is inserted at the center of a time slot. This midamble is created by circulating one basic midamble code on the transmission side.
[0003]
A method of creating a midamble will be described with reference to FIG. Midambles 1001-1 to 1001-8 are 144 chips long, and are combined with two known series of basic midambles 1002 consisting of 128 chips and cyclically shifted every 16 chips within this range for 8 users ( 8 types). Each user signal is assigned with one of eight types of midambles and transmitted. As a method for assigning midambles to users, a Default midamble assignment method in which the relationship between a spreading code and a midamble code to be used is determined in advance, a User specific midamble assignment method in which individual midamble codes are used for each user, and There are three common midamble allocation schemes in which a midamble code common to all users is used.
[0004]
On the receiving side, when calculating the midamble correlation, the correlation calculation is performed while cyclically shifting the basic midamble code every 16 chips, and based on the calculation result, the midamble 1001-1 to the midamble 1001-8 are sequentially performed. A continuous delay profile is created. Then, a path is selected from the created delay profile, the selected path is rake synthesized, and JD processing is performed using the rake synthesis result and the delay profile.
[0005]
In this way, the delay profile created from the midamble of codes different for each user is created as a continuous delay profile for each user, but the peak of the back user is the delay of the previous user due to the characteristics of the reception filter. May appear behind the profile.
[0006]
[Problems to be solved by the invention]
However, in the conventional receiving apparatus, even when another user's peak appears behind the delay profile of his / her own, the user selects the path as his / her path and performs rake composition and JD processing. There is a problem that deterioration occurs.
[0007]
The present invention has been made in view of such a point, and when a peak of another user appears behind the delay profile, a receiving apparatus and a receiving method capable of demodulating a received signal without causing characteristic deterioration The purpose is to provide.
[0008]
[Means for Solving the Problems]
The receiving apparatus of the present invention includes a correlation calculation unit that performs a correlation calculation between a midamble included in a reception signal and a midamble sequence obtained by circulating a predetermined amount of basic midambles, and a correlation calculation unit for each user based on a calculation result of the correlation calculation. A delay profile creating means for creating a delay profile; a path selecting means for selecting a peak exceeding a threshold in the delay profile as a path; and the delay of another user using a midamble of a cyclic amount immediately after each user. Invalid path determination means for excluding from the selection a path existing within the last predetermined number of samples in the delay profile of each user based on whether or not the selected path exists within a predetermined number of samples from the beginning of the profile; The demodulated signal is demodulated for each user using the path left by the invalid path determination means. It adopts a configuration comprising a means.
[0009]
According to this configuration, the path existing within the last predetermined number of samples of the delay profile created for each user is removed from the selection, and the received signal is demodulated using the remaining path. It is possible to prevent deterioration of characteristics due to selection and demodulation.
[0010]
The receiving apparatus of the present invention has user determination means for determining whether or not communication is being performed for each user based on a delay profile for each user, and the invalid path determination means is not in communication by the user determination means. The user who uses the midamble of the circulation amount immediately before the user determined to have the configuration of leaving all the paths selected by the path selection means.
[0011]
According to this configuration, it is determined whether or not communication is performed for each user, and based on the determination result, it is determined whether or not to select a path when demodulating the path within the last predetermined number of samples. When it is determined that it is its own path, all the paths selected by the path selection means are left, so that the number of paths that can be used for demodulation increases and the quality of the received signal can be improved.
[0012]
In the receiving apparatus of the present invention, the invalid path determination means uses the path selection means in a user who uses a midamble of a cyclic amount immediately before a user for which there is no path selected within a predetermined number of samples from the head of the delay profile. A configuration is adopted in which all the selected paths are left.
[0013]
According to this configuration, a user whose correlation peak is formed immediately before a user who does not have a selected path within the predetermined number of samples from the beginning of the delay profile demodulates using all the selected paths, and thus can be used for demodulation. The number of paths can be increased and the quality of the received signal can be improved.
[0014]
In the receiving apparatus according to the present invention, the demodulating unit rake-combines the received signals of the respective users based on the paths left by the invalid path determining unit, and the rake-combined received signal and invalid path determining unit A configuration in which JD demodulation is performed using the remaining path is adopted.
[0015]
According to this configuration, JD demodulation is performed using a rake-combined received signal that does not have characteristic degradation, so that a received signal that has no characteristic degradation can be obtained even after JD demodulation.
[0016]
The communication terminal device of the present invention employs a configuration including any one of the above receiving devices. Moreover, the base station apparatus of this invention takes the structure which comprises either of said receivers.
[0017]
According to these configurations, it is possible to prevent characteristic deterioration caused by erroneously selecting another user's path and performing rake composition.
[0018]
The reception method of the present invention includes a correlation calculation step for performing a correlation calculation between a midamble included in a reception signal and a midamble sequence obtained by circulating a predetermined amount of the basic midamble, and a correlation calculation step for each user based on the calculation result of the correlation calculation. A delay profile creation process that creates a continuous delay profile, a path selection process that selects a peak that exceeds a threshold value in the delay profile as a path, and other users who use the midamble of the cyclic amount immediately after each user. Based on whether the selected path exists within a predetermined number of samples from the head of the delay profile, an invalid path determination that excludes from the selection a path existing within the last predetermined number of samples in the delay profile of each user. And a demodulation step of demodulating the received signal for each user using the remaining path Is Rukoto.
[0019]
According to this method, the path existing within the last predetermined number of samples of the delay profile created for each user is deselected, and the received signal is demodulated using the remaining path. It is possible to prevent deterioration of characteristics due to selection and demodulation.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
The gist of the present invention is to obtain received data by performing rake synthesis and JD processing without selecting a path within the last predetermined number of samples in the delay profile. In addition, it is determined whether or not communication is performed for each user from the delay profile. If communication is not being performed, the last predetermined delay profile of another user created immediately before the delay profile of the user who is not communicating Rake synthesis and JD processing are performed using all selected paths including paths existing within the number of samples to obtain received data of other users.
[0021]
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0022]
(Embodiment 1)
FIG. 1 is a diagram showing a configuration of a receiving apparatus according to the present embodiment, and FIGS. 2 to 5 are delay profiles for each user created in the receiving apparatus according to the present embodiment. The reception apparatus according to the present embodiment includes an antenna 101, a radio reception unit 102, a correlation processing unit 103, a delay profile creation unit 104, a midamble shift determination unit 105, a path selection unit 106, an invalid path determination unit 107, and a JD calculation unit 108. And a despreading / rake combining unit 109.
[0023]
Radio receiving section 102 performs predetermined radio processing such as down-conversion on the signal received by antenna 101, and outputs the result to correlation processing section 103 and despreading / rake combining section 109. The correlation processing unit 103, which is a correlation calculation unit, performs a correlation calculation between a pilot signal unit called a midamble included in the received signal output from the radio reception unit 102 and a midamble sequence obtained by circulating a predetermined basic midamble. And output to the delay profile creation unit 104.
[0024]
The delay profile creation unit 104 creates a delay profile of the signal output from the correlation processing unit 103 for each user and outputs the delay profile to the midamble shift determination unit 105, as shown in FIGS. Here, the user 1 is a user who uses the midamble of the cyclic amount immediately before the user 2, and the user 2 is a user who uses the midamble of the cyclic amount immediately before the user 3. The same applies to the user 7. And the user 8 is a user who uses the midamble of the circulation amount immediately before the user 1. In addition, since user 5 to user 8 in this embodiment are not communicating, only four types of delay profiles are illustrated in FIGS. 2 to 5, but in reality, delay profile creation unit 104 has eight users. For each user from midamble 1001-1 to midamble 1001-8, eight types of continuous delay profiles are created in order from the front to the rear.
[0025]
The midamble shift determination unit 105 serving as a user determination unit determines, for each user, whether or not the delay profile created by the delay profile creation unit 104 exceeds a preset power value threshold value, and the determination result is obtained. Output to the invalid path determination unit 107. This determination is based on the assumption that each user has a power profile of 0.05 as a threshold value 201, 301, 401, 501, and a user who has a delay profile that has a peak exceeding the threshold value is currently communicating. It is determined that The threshold value can be changed as appropriate. Since user 1 has peaks 202, 203, and 204 that exceed the threshold value, it is determined that user 1 is currently communicating. Since user 2 has peaks 302, 303, and 304 that exceed the threshold, it is determined that the user 2 is currently communicating. User 3 is determined to be currently communicating because there is a peak 402 exceeding the threshold. Since there is no peak exceeding the threshold, the user 4 is determined not to be currently communicating.
[0026]
The path selection unit 106 selects, as a path, a peak that exceeds a preset threshold using the delay profile of each user, and outputs the selected path to the invalid path determination unit 107. User 1 selects paths 202, 203, and 204 that exceed threshold 201, user 2 selects paths 302, 303, and 304 that exceed threshold 301, and user 3 exceeds threshold 401 Since the path 402 is selected, the user 4 does not select a path because there is no path exceeding the threshold 501. Note that a threshold different from the threshold used in the midamble shift determination unit 105 may be used as a threshold used in path selection. The threshold setting in the path selection unit 106 is a method of setting for each user by multiplying a peak power value for each user by a predetermined constant, and a value obtained by multiplying the noise level by a constant is the threshold. Any method can be applied, such as a method for setting a threshold value obtained for one user and a threshold value obtained for one user as a common threshold value for all users.
[0027]
The invalid path determination unit 107 determines the last 8 samples in the delay profile based on the user information input from the midamble shift determination unit 105 and information on whether or not the selected path exists in 10 samples from the beginning of the delay profile. If there is a selected path, it is determined whether or not to exclude the path from the selection. As shown in FIGS. 2 to 5, one black circle on the delay profile is one sample, and is sampled at a predetermined cycle. In user 1, since user 2 is communicating and there is a selected path 302 in 10 samples from the head of the delay profile of user 2, the selected path 204 in the last 8 samples is excluded from the selection. To do. In addition, in user 2 in which a correlation peak is formed immediately before user 3, user 3 is communicating, but since there is no path selected within 10 samples from the top of the delay profile of user 3, The selected path 304 in 8 samples is left without being excluded. In addition, in the user 3 in which a correlation peak is formed immediately before the user 4, since the user 4 is not communicating, it is determined whether or not there is a selected path within 10 samples from the head of the delay profile of the user 4. Without doing so, the selected paths in the last 8 samples are left without being excluded. However, since there is no valid path exceeding the threshold in the last 8 samples, the user 3 does not select a path from the last 8 samples. The path thus selected is output to the JD calculation unit 108 and the despreading / rake combining unit 109.
[0028]
Note that if there is a peak in the last 8 samples in the delay profile of the user 4, whether or not to select that peak as the path of the user 4 is determined from user information based on the delay profile of the user 5. Then, the user 5 to the user 8 are determined in the same manner. When the determination to the user 8 is completed, it is next determined whether or not the user 1 is communicating. If the user 1 is determined to be communicating, the user 8 The peak in the last 8 samples is not selected as the user 8 path.
[0029]
Based on the received signal rake-combined by the despreading / rake combining unit 109 and the delay profile generated by the delay profile generating unit 104, the JD calculation unit 108 serving as a demodulating unit converts the received signal into a received signal over one time slot. JD arithmetic processing is performed and output to a decoding unit not shown in the figure to obtain received data. Here, the JD calculation is a calculation method as described in Japanese Patent Application No. 2001-156625, for example. The despreading / rake combining unit 109 serving as a demodulating unit performs despreading and rake combining using the selected path information input from the invalid path determining unit 107 and the received signal input from the wireless receiving unit 102, and a JD operation unit 108. Output to. The user 1 performs rake composition using the selected paths 202 and 203. User 2 performs rake composition using the selected paths 302, 303, and 304. User 3 performs rake composition using the selected path 402.
[0030]
Next, the operation of the receiving apparatus in this embodiment will be described using the flowcharts of FIGS. The reception signal received by the antenna 101 is subjected to correlation calculation by the correlation processing unit 103, and a delay profile generation unit 104 generates a delay profile from the reception signal subjected to the correlation calculation (step (hereinafter referred to as “ST”). 601). Next, midamble shift creation section 105 performs midamble shift determination (ST602), and outputs the determination result to invalid path determination section 107 and to path selection section 106. Next, path selection section 106 selects a peak that exceeds the threshold value from the delay profile as a path (ST603), and outputs the selected path information to invalid path determination section 107.
[0031]
The invalid path determination unit 107 sets 1 to the midamble k (ST604), and the user using the midamble k + 1 is currently determined from the information of the user currently communicating input from the midamble shift determination unit 105. It is determined whether communication is in progress (ST605). For example, if midamble k is midamble 1001-2 in FIG. 10, midamble k + 1 becomes midamble 1001-3. That is, the midamble k and the midamble k + 1 are midambles that are shifted by 16 chips as shown in FIG. If the user of midamble k + 1 is communicating, it is determined whether there is a path selected by the user of midamble k + 1 within the 10 samples from the beginning of the delay profile of the user of midamble k + 1 (ST606). . On the other hand, if the user using midamble k + 1 is not communicating in ST605, the paths existing in the last 8 samples are left. In ST606, if there is a path selected within 10 samples from the head of the delay profile of the user of midamble k + 1, the path existing in the last 8 samples is removed from the selection (ST607). On the other hand, in ST606, when there is no path selected in the 10 samples from the head of the delay profile of the user of midamble k + 1, the selection of the path existing in the last 8 samples is left without being excluded.
[0032]
Next, it is determined whether or not k = 4 (ST608). If k = 4, 1 is added to the value of k (ST609), and if k = 4, it is determined whether the user of midamble 1 is currently communicating (ST610). When the user of midamble 1 is currently communicating, it is determined whether there is a path selected by the user of midamble 1 within the 10 samples from the beginning of the delay profile of the user of midamble 1 ( ST611). On the other hand, if the user of midamble 1 is not currently communicating in ST610, the paths existing in the last 8 samples are left. In ST611, if there is a path selected in the 10 samples from the head of the delay profile of the user of midamble 1, the path existing in the last 8 samples is removed from the selection (ST612). On the other hand, in ST611, when there is no path selected in the 10 samples from the head of the delay profile of the user of midamble 1, the selection of the path existing in the last 8 samples is left without being excluded. Next, JD operation section 108 performs JD processing for each user using the selected path (ST613), and decodes this to obtain received data.
[0033]
As described above, according to the receiving apparatus of the present embodiment, midamble shift determination section 105 determines whether or not a user using a midamble shifted by 16 chips is communicating, and shifts by 16 chips. If the user using the midamble is in communication, the path existing in the last 8 samples is removed. Therefore, the characteristic degradation caused by erroneously selecting another user's path and performing rake synthesis and JD calculation. Can be prevented. In addition, if the user using the midamble shifted by 16 chips is not communicating, the path existing in the last 8 samples can be regarded as the own path. High received data can be obtained.
[0034]
In the present embodiment, it is determined whether or not a path exists in 10 samples from the head of the delay profile of the user 3, but the number of samples for determining whether or not a path exists is as follows. It can be any number of samples other than 10 samples. In addition, the users other than the user 2 and the user 3 can be applied as long as they are users whose delay profiles are continuously created.
[0035]
(Embodiment 2)
FIG. 8 is a diagram showing the configuration of the receiving apparatus according to the second embodiment. In the present embodiment, the configuration in which the midamble determination unit 105 is not provided in FIG. 7 is different from the configuration in FIG. 1, and the other configurations are the same as those in FIG. Is omitted.
[0036]
The invalid path determination unit 107 does not select all of the selected paths input from the path selection unit 106 when the selected paths exist in the last eight samples. Therefore, the path information selected except for the paths in the last 8 samples in the delay profiles of all users is output to the despreading / rake combining unit 109 and the JD calculating unit 108.
[0037]
Next, the operation of the receiving apparatus in this embodiment will be described using the flowchart of FIG. The reception signal received by antenna 101 is subjected to correlation calculation by correlation processing section 103, and a delay profile generation section 104 generates a delay profile from the reception signal subjected to correlation calculation (ST901). Next, path selection section 106 selects a peak that exceeds the threshold value from the delay profile as a path (ST902), and outputs the selected path information to invalid path determination section 107. The invalid path determination unit 107 sets 1 to the midamble k (ST903), and if there is a selected path in the last 8 samples, the selection of the path is stopped (ST904). Next, it is determined whether or not k = 5 (ST905). If k = 5, the JD processing unit 108 performs JD processing for each user using the selected path (ST907), and decodes this to obtain received data. On the other hand, if k = 5 is not satisfied in ST905, 1 is added to the value of k (ST906).
[0038]
As described above, according to the receiving apparatus of the present embodiment, the user using the midamble shifted by 16 chips is uniformly selected within the last 8 samples regardless of whether or not the user is currently communicating. When there is a path, the selection is stopped, so that a circuit for determining whether or not the user using the adjacent midamble shift is currently communicating is unnecessary, and the circuit configuration is simplified. The device can be downsized. In addition, when there is a selected path in the last 8 samples, rake composition is performed using a path excluding the path, and therefore, by selecting another user's path by mistake and performing rake composition and JD calculation. Characteristic deterioration can be prevented.
[0039]
In the first embodiment and the second embodiment, the number of samples for determining whether there is an unselected path is the last eight samples. However, the number of samples for determining whether there is an unselected path. Can be set arbitrarily. In the first embodiment and the second embodiment, the midamble is generated by shifting 16 chips. However, if the delayed wave of the user before and after is not selected by mistake, the midamble is 16 chips. The same effect can be obtained by using a midamble created while shifting with the number of chips other than. Further, a demodulation method other than JD demodulation may be used as the demodulation method.
[0040]
【The invention's effect】
As described above, according to the present invention, it is possible to demodulate a received signal without causing characteristic deterioration when another user's peak appears even though there is no path at the end of the delay profile. it can.
[Brief description of the drawings]
1 is a block diagram showing a receiving apparatus according to Embodiment 1 of the present invention; FIG. 2 is a delay profile of user 1 in the receiving apparatus according to Embodiment 1 of the present invention; FIG. 4 shows a delay profile of the user 3 in the receiving apparatus according to the first embodiment of the present invention. FIG. 5 shows a delay profile of the user 2 in the receiving apparatus according to the first embodiment of the present invention. FIG. 6 is a flowchart showing the operation of the receiving apparatus according to the first embodiment of the present invention. FIG. 7 is a flowchart showing the operation of the receiving apparatus according to the first embodiment of the present invention. FIG. 9 is a block diagram showing a configuration of a receiving apparatus according to Embodiment 2 of the present invention. FIG. 9 is a flowchart showing an operation of the receiving apparatus according to Embodiment 2 of the present invention. Explanation of symbols
104 delay profile creation unit 105 midamble shift determination unit 106 path selection unit 107 invalid path determination unit 108 JD operation unit 109 despread / rake combination unit

Claims (7)

Correlation calculation means for performing a correlation operation between a midamble included in the received signal and a midamble sequence obtained by circulating a predetermined amount of the basic midamble, and a delay profile for creating a delay profile for each user based on the calculation result of the correlation calculation Creating means, path selecting means for selecting a peak exceeding a threshold in the delay profile as a path, and a predetermined number of samples from the head of the delay profile of another user using the midamble of the cyclic amount immediately after each user An invalid path determining means for excluding a path existing in the last predetermined number of samples in the delay profile of each user from selection based on whether or not the selected path exists in the user, and the invalid path determining means And demodulating means for demodulating the received signal for each user using the remaining path. Receiving apparatus according to claim and.   User determining means for determining whether or not communication is being performed for each user based on a delay profile for each user, and the invalid path determining means is immediately before the user determined to be not communicating by the user determining means. 2. The receiving apparatus according to claim 1, wherein all the paths selected by the path selection unit are left in a user who uses a midamble having a cyclic amount of 5.   The invalid path determination means includes all paths selected by the path selection means in a user who uses a midamble of a cyclic amount immediately before a user for which there is no path selected within a predetermined number of samples from the head of the delay profile. The receiving apparatus according to claim 1 or 2, wherein: The demodulating means rake-combines each user's received signal based on the path left by the invalid path determining means, and uses the rake-combined received signal and the path left by the invalid path determining means. The receiving apparatus according to claim 1, wherein JD demodulation is performed.   A communication terminal device comprising the receiving device according to claim 1.   A base station apparatus comprising the receiving apparatus according to claim 1. A correlation calculation step for performing a correlation operation between a midamble included in the received signal and a midamble sequence obtained by circulating a predetermined amount of basic midambles, and creating a continuous delay profile for each user based on the calculation result of the correlation calculation A delay profile creation step, a path selection step of selecting a peak exceeding a threshold in the delay profile as a path, and a predetermined amount from the beginning of the delay profile of another user using a midamble of a cyclic amount immediately after each user An invalid path determination step of excluding from the selection a path existing within the last predetermined number of samples in the delay profile of each user based on whether or not the selected path exists within the number of samples, and a remaining path And a demodulation step of demodulating the received signal for each user using Shin method.

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