JP3551254B2 - Path detecting method, path detecting apparatus, and array antenna receiving apparatus - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a path detection apparatus for an array antenna system, and more particularly, to a path detection apparatus that receives a code division multiple access (CDMA) signal at an array antenna system, detects each timing of multipath, and forms an initial antenna beam of each path. It relates to a detection device.
[0002]
[Prior art]
It is said that the code division multiple access (CDMA) system increases the subscriber capacity for the frequency band as compared with the conventional system, and is expected as a wireless access system for the next generation mobile communication system.
[0003]
In a CDMA mobile communication system, a plurality of user signals coexist on the same frequency. Therefore, in a receiving device of a base station, another user signal becomes an interference wave with respect to a desired user signal. As means for reducing the influence of this interference, there is an adaptive array antenna. The adaptive array antenna receives signals with a plurality of antennas, weights the signals received by each antenna with a complex number (hereinafter, referred to as antenna weight), and combines them (hereinafter, referred to as antenna combining). By controlling the amplitude and phase of the received signal at each antenna, a directional beam suitable for a desired user signal is formed, and interference due to other user signals is suppressed.
[0004]
Also, in a CDMA mobile communication system, a receiving device of a base station detects signals of a plurality of paths having different arrival timings (hereinafter, referred to as path timings) generated by a multipath propagation path, and rake-combines the signals. To demodulate the user signal. Also in rake combining, each path is weighted (hereinafter referred to as rake weight).
[0005]
The path detection device in the reception device of the base station detects the path timing of each path and notifies the reception demodulation unit of each path timing. The reception demodulation unit despreads signals received by a plurality of antennas at each path timing notified from the path detection device. The reception demodulation unit combines the reception signals from the respective antennas with the directional beams. Further, the reception demodulation unit rakes the signals of each path to obtain a demodulation result of the user signal.
[0006]
In a receiving system having a plurality of antennas, such as an adaptive array antenna, the SINR (signal-to-interference power ratio) per antenna decreases in proportion to the number of antennas. Therefore, when path detection is performed using only one antenna, the accuracy of path detection decreases.
[0007]
Therefore, conventionally, a path detection device using reception signals of a plurality of antennas has been proposed. For example, in a conventional path detection device using a plurality of antennas, a delay profile is generated for each antenna, and the delay profiles are smoothed by combining the delay profiles to improve characteristics.
[0008]
FIG. 8 shows a configuration example of a conventional receiving apparatus.
[0009]
The conventional receiving device includes a path detection device 801 and a reception demodulation unit 806.
[0010]
The path detection device 801 receives a CDMA signal by an array antenna (not shown) and performs path detection. Here, it is assumed that the array antenna is composed of M antennas.
[0011]
The path detection device 801 includes a sliding correlator 802, a delay profile generation unit 803 for each antenna, a delay profile synthesis unit 804, and a path timing detection unit 805.
[0012]
The sliding correlator 802 spreads the spread signals S811, S812,..., S81M received by each antenna over a plurality of chips and outputs 1 / N of the chip period. _R (N _R Are despread with a resolution of 1 or more) and output them as despread signal sequences.
[0013]
The per-antenna delay profile generation unit 803 calculates the amplitude level or power level of the despread signal sequence output from the sliding correlator 802 by taking the vector average in phase. Further, the antenna-dependent delay profile generation unit 803 averages the amplitude level or power level of the vector average of the despread signal sequence for a predetermined time. Accordingly, the antenna-dependent delay profile generation unit 803 generates a delay profile corresponding to each antenna, averaged over a predetermined time.
[0014]
Delay profile combining section 804 combines the delay profiles corresponding to each antenna to generate one delay profile (hereinafter, referred to as a combined delay profile).
[0015]
The path timing detection unit 805 selects L path timings used for rake combining in the reception demodulation unit according to the combined delay profile. As a method of selecting a path timing in the path timing detection unit 805, there is a method of sequentially selecting paths having a larger amplitude level or power level from a combined delay profile. However, a path selection interval of 0.75 to 1 chip is generally set. That is, a path that is 0.75 to 1 chip before and after the previously selected path is not selected.
[0016]
The reception demodulation unit 806 includes L path reception units 8071, 8072,..., 807L and a combiner 812, demodulates the signal of each path at the path timing detected by the path detection unit 801 and rake-combines the signals. Output a signal.
[0017]
The path receiving unit 8071 includes a correlator 8081, a beamformer 8091, a rake combining weighting unit 8101, and a weight adaptation control unit 8111.
[0018]
Similarly, the path receiving units 8072,..., 807L correspond to the correlators 8082,. , 811L. , 807L have the same configuration, and receive spread signals S811, S812,..., S81M at the respective corresponding path timings.
[0019]
The following description focuses on the path receiving unit 8071.
[0020]
The correlator 8081 despreads the spread signals S811, S812,..., S81M received by each antenna at the path timing detected by the path timing detection unit 805.
[0021]
The beamformer 8091 receives each output of the correlator 8081, performs antenna combining with a given weight (antenna weight) for forming a directional beam adapted to each user, and outputs a path signal S821.
[0022]
Rake combining weighting section 8101 performs weighting (rake weighting) on path signal S821 to compensate for carrier phase fluctuation and maximize combined SINR, and outputs weighted path signal S831.
[0023]
The weight adaptation control unit 8111 adaptively updates the antenna weight using the output of the correlator and the determination error of the path signal S821. As a control operation of the weight adaptive control unit 8111, for example, least mean square error (MMSE) control or the like is used. The MMSE is described in detail in Japanese Patent Application No. 2000-256549.
[0024]
The combiner 812 generates high-quality rake-combined demodulated outputs by adding the weighted path signals S831, S832,..., S83L output from the rake combining weighting units 8101, 8102,.
[0025]
[Problems to be solved by the invention]
The conventional path detection device 801 smoothes the delay profile by synthesizing the delay profile of each antenna by level (amplitude or power), and improves the path detection characteristics by ensuring the discrimination between the path peak and noise. I do. However, since the path detection device 801 does not directly improve the SINR (difference between the peak of the path and the noise level) of each delay profile, the improvement of the path detection characteristics is limited.
[0026]
Further, the conventional path detection device 801 can detect the timing of each path, but cannot know the initial directivity beam used for the antenna combining in the beam former 809 of the reception / demodulation unit 806. For example, a predetermined initial directional beam is used. If a preferred initial directional beam can be known, a better antenna combining effect than at the initial time can be obtained.
[0027]
SUMMARY OF THE INVENTION It is an object of the present invention to provide a path detection device that has a high effect of improving path detection characteristics in an array antenna reception device and also detects an initial directional beam used for antenna synthesis.
[0028]
[Means for Solving the Problems]
In order to achieve the above object, a path detection method according to the present invention is a path detection method for receiving a code division multiple access signal with an array antenna and detecting multipath timing, wherein each antenna of the array antenna Receiving the despread signal sequence with a plurality of directional beams, generating a delay profile for each of the directional beams, and at least a level value greater for each timing than the delay profile for each directional beam. Select one delay profile,
When the number of selections of the delay profile is one, the selected level value is used, and when the number of selections is plural, the sum of the level values of the selected delay profile is used. Generating a combined delay profile; and detecting the timing of the multipath from the combined delay profile.
[0029]
According to the present invention, a despread signal sequence of each antenna is received by a plurality of directional beams, and each timing of multipath is detected from a combined delay profile obtained by selectively adding a level value from a delay profile for each directional beam. I do.
[0030]
According to the embodiment of the present invention, the timing of the multipath is detected from the combined delay profile, and each path is received from level information indicating a level value for each timing in the delay profile of each directional beam. The initial value of the directional beam for path reception for generating
[0031]
Therefore, the initial weight of the directional beam for receiving each path can be generated using the level information indicating the level value of each delay profile at each timing detected when detecting the timing of each path of the multipath.
[0032]
A path detection device of the present invention is a path detection device that receives a code division multiple access signal by an array antenna and detects the timing of multipath, and reverses a signal over a plurality of chips for each antenna of the array antenna. Spreading, a sliding correlator that outputs a despread signal sequence, a multi-beamformer that receives the signal sequence output for each antenna with a plurality of directional beams, and outputs a signal sequence for each directional beam, Taking an average of the signal sequence for each directional beam at a predetermined time and generating a delay profile for each beam which generates a delay profile for each directional beam, Select at least one delay profile with a large level value, When the number of selections of the delay profile is one, the selected level value is used, and when the number of selections is plural, using the sum of the level values of the selected delay profile, A delay profile selecting / combining unit for generating a combined delay profile; and a path timing detecting unit for detecting the timing of the multipath from the combined delay profile.
[0033]
According to the embodiment of the present invention, based on level information indicating a level value for each timing in the delay profile of each directional beam, an initial value of an antenna weight for forming a directional beam for path reception for receiving each path is obtained. The apparatus further includes initial weight generation means for generating a value.
[0034]
The receiving apparatus of the present invention is a receiving apparatus that receives a code division multiple access signal by an array antenna and rake-combines a multipath signal, and despreads a signal across a plurality of chips for each antenna of the array antenna. A sliding correlator that outputs a despread signal sequence; a multi-beamformer that receives the signal sequence output for each antenna with a plurality of directional beams and outputs a signal sequence for each directional beam; An average of the signal sequence for each directional beam at a predetermined time, and a delay profile generating means for each beam for generating a delay profile for each directional beam; and a level for each timing based on the delay profile for each directional beam. Select at least one delay profile with a large value, When the number of selections of the delay profile is one, the selected level value is used, and when the number of selections is plural, using the sum of the level values of the selected delay profile, Delay profile selecting / combining means for generating a combined delay profile; path timing detecting means for detecting the timing of the multipath from the combined delay profile; and a level value for each timing in the delay profile of each directional beam. Initial weight generation means for generating an initial value of an antenna weight for forming a directional beam for receiving a path for receiving each path from the level information shown, and receiving at the array antenna corresponding to the timing of the multipath. At least one correlator for despreading each spread signal obtained at the timing, and a directional beam for path reception provided with a given antenna weight, provided for the correlator, and the corresponding correlator A beam former for receiving the output signal from the path receiving directional beam, It is provided corresponding to the beamformer, the antenna weight is used as the initial value at the time of the initial operation, and thereafter, the antenna weight is adaptively adjusted using the signal despread by the correlator and the determination error of the beamformer. Weight adaptive control means for updating and giving to the beamformer, and an output of the corresponding beamformer provided corresponding to the beamformer so as to compensate for carrier phase fluctuation and maximize SINR after rake combining. And a combiner for adding the outputs of the rake combining weighting means to generate a demodulated output.
[0035]
According to an embodiment of the present invention, the delay profile selecting / synthesizing means selects a delay profile having a largest level value for each timing from the delay profiles for each of the directional beams, and sets the level value to the combined delay. This is the profile level value.
[0036]
According to an embodiment of the present invention, the delay profile selecting / combining means includes: When the selection number is plural, From the delay profile for each directional beam, a delay profile having the largest level value and a delay profile having the second largest level value are selected for each timing, and the level values are added to generate a combined delay profile.
[0037]
According to an embodiment of the present invention, the delay profile selecting / combining means includes: When the selection number is plural, For each timing of the delay profile for each directional beam, when the delay profile with the largest level value and the delay profile with the second largest level value are those of the directional beams adjacent to each other, The second largest value is added to the value to generate the combined delay profile.
[0038]
According to an embodiment of the present invention, the delay profile selecting / combining means includes: When the selection number is plural, For each timing of the delay profile for each directional beam, from the one with the largest level value Multiple The composite delay profile is generated by sequentially adding the level values of the N delay profiles.
[0039]
According to an embodiment of the present invention, the delay profile selecting / combining means includes: When the selection number is plural, For each timing of the delay profile for each of the directional beams, within a predetermined range from the level value of the delay profile with the largest level value, from the one with the largest level value Multiple The composite delay profile is generated by sequentially adding the level values of the N delay profiles.
[0040]
According to an embodiment of the present invention, the delay profile selecting / combining means includes: When the selection number is plural, At each timing of the delay profile for each directional beam, the level value is higher than the average noise level of the delay profile for each directional beam by a predetermined level or more, and from the largest level value Multiple The composite delay profile is generated by sequentially adding the level values of the N delay profiles.
[0041]
According to an embodiment of the present invention, the initial weight generation means sets the weight of the directional beam having the largest level value from the level information as the initial weight.
[0042]
According to the embodiment of the present invention, the initial weight generation means may include the level value of the directional beam having the largest level value from the level information, and the next level value of the directional beam adjacent to the directional beam. According to the ratio of the large directional beam to the level value, a weight for forming the directional beam having the largest level value, or a directional beam intermediate between the directional beam and the adjacent directional beam is used. The weight to be formed is set as an initial weight.
[0043]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiments of the present invention will be described in detail with reference to the drawings.
[0044]
Referring to FIG. 1, an array antenna receiving device according to one embodiment of the present invention includes a path detecting device 101 and a receiving and demodulating unit 108. Here, it is assumed that the array antenna (not shown) includes N antennas.
[0045]
The path detection apparatus 101 includes a sliding correlator 102, a multi-beamformer 103, and a beam-based delay profile generation unit 104 in order to detect a path suitable for rake combining from a code division multiple access (CDMA) signal received by an array antenna. , A delay profile selection / synthesis unit 105, a path timing detection unit 106, and an initial weight generation unit 107.
[0046]
The reception demodulation section 108 includes L path reception sections 1091, 1092,..., 109L and a combiner 114. The reception demodulation unit 108 demodulates the signal of each path at the path timing detected by the path detection device 101, performs rake combining, and generates a demodulated output. In this rake combining, signals of a maximum of L paths are combined. The path receiving unit 1091 includes a correlator 1101, a beamformer 1111, a rake combining weighting unit 1121, and a weight adaptation control unit 1131. Similarly, the path receiving units 1092,..., 109L include the corresponding correlators 1102,. .., 113L. , 109L have the same configuration, and receive the spread signals S111, S112,..., S11N at the respective corresponding path timings.
[0047]
The sliding correlator 102 spreads the spread signals S111, S112,... S11N received by each antenna over a plurality of chips, _R (N _R Are despread at resolutions of 1 or more) and output as despread signal sequences S121, S122,..., S12N.
[0048]
The multi-beamformer 103 receives the despread signal sequences S121, S122,..., S12N output from the sliding correlator 102 with M directional beams (hereinafter, referred to as multi-directional beams). , S13M are output.
[0049]
Referring to FIG. 2, the multi-beamformer 103 includes multipliers 2111, 112,..., 211N, multipliers 2121, 122,. .., 22M.
[0050]
, 212N weight the signal sequences S121, S122,..., S12N, respectively. The combiner 211 combines the outputs of the multipliers 2111, 122,..., 212N and outputs a signal sequence S131.
[0051]
Similarly, multiplier 2122 weights signal sequence S122. The combiner 222 combines the outputs of the multipliers 2121, 122,..., 212N to generate a signal sequence S132. In the same manner, the same applies to multipliers 21M1, 21M2,..., 21MN and combiner 22M. Note that the multi-beamformer 103 can be made into an IC, and in that case, the amount of software calculation is almost the same as that of the conventional one.
[0052]
The weights given to the multipliers 2111, 112,..., 211N, the multipliers 2121, 1222,. This is a predetermined value for performing
[0053]
FIG. 6 is a graph showing an example of multi-directional beams of the multi-beamformer 103 when the number of directional beams is M = 6 and the number of antennas is N = 6. In an array antenna in which six antennas are linearly arranged, 6 is shown. An orthogonal multi-beam pattern comprising three directional beams is shown.
[0054]
FIG. 7 is a graph showing an example of a multi-directional beam of the multi-beamformer 103 when the number of directional beams M = 12 and the number of antennas N = 6. In an array antenna in which six antennas are linearly arranged, 12 is shown. An orthogonal multi-beam pattern comprising three directional beams is shown.
[0055]
The beam-by-beam delay profile generation unit 104 averages the signal sequences S131, S132,..., S13M input from the multi-beamformer 103 in a fixed period, and generates beam-by-beam delay profiles S141, S142,. I do.
[0056]
FIG. 3 is a block diagram showing a configuration of the beam-based delay profile generation unit 104. The beam-by-beam delay profile generation unit 104 includes a beam-by-beam in-phase averaging unit 301, a beam-by-beam level detection unit 302, and a beam-by-beam level averaging unit 303.
[0057]
The beam-by-beam in-phase averaging unit 301 performs vector averaging in phase for a predetermined number of symbols of the signal sequences S131, S132,..., S13M input from the multi-beamformer 103. The beam level detection unit 302 calculates the level (amplitude or power) of each output of the beam in-phase averaging unit 301. The beam level averaging unit 303 averages each output of the beam level detecting unit 302 for a predetermined time, and generates delay profiles S141, S142,..., S14M.
[0058]
The beam-by-beam in-phase averaging unit 301 adds the phases of the despread symbols of the signal sequences S131, S132,..., S13M, and performs vector addition, so that the SINR is significantly improved.
[0059]
If the symbol is modulated, the modulation must be removed. In that case, if it is a pilot signal, modulation can be removed with a known pilot symbol, and addition in phase is possible.
[0060]
The SINR is improved as the number of symbols for which the in-phase averaging is performed is large. However, when the phase changes rapidly due to fading or the like, the number of symbols to be averaged is limited. The number of symbols to be averaged by the in-beam in-phase averaging section 301 and the method of average weighting are arbitrary, and an optimum one may be selected according to the mode to which the present apparatus is applied.
[0061]
Further, in the path detection apparatus 101 of the present embodiment, the in-phase in-phase averaging unit 301 may be placed before the multi-beamformer 103. This configuration may reduce the amount of calculation in some cases. In this case, the per-beam in-phase averaging unit 301 takes the in-phase average for each antenna instead of taking the in-phase average for each beam. This case is similar in principle, and is included in the present invention.
[0062]
The delay profile selection / synthesis unit 105 measures the levels of the M delay profiles S141, S142,..., S14M at each timing, and selects the level from each of the delay profiles S141, S142,. One or more delay profiles having a large delay profile are selected, and their level values are added to generate one delay profile (hereinafter, referred to as a combined delay profile), which is output to the path timing detection unit 106. The delay profile selection / synthesis unit 105 notifies the initial weight generation unit 107 of the result of measuring the level of each delay profile S141, S142,..., S14M at each timing as level information.
[0063]
The delay profile selection / synthesis unit 105 is a constituent element of the present invention, and several methods can be considered for its selection and synthesis method. The suitable means differs depending on the shape of the multi-beam pattern.
[0064]
For example, when multi-directional beams are densely arranged as shown in FIG. 7, even if a signal arrives from an intermediate direction between two directional beams, the level is deteriorated only by selecting one directional beam. Almost no. Therefore, the delay profile selection / synthesis unit 105 may select one large-level delay profile from the M delay profiles for each timing, and use that level as the level of the composite delay profile.
[0065]
On the other hand, when each directional beam of the multi-directional beams is sparsely arranged, one directional beam is selected when the signal arrives from an intermediate direction between the two directional beams. Alone alone will cause a significant degradation of the level.
[0066]
When only one directional beam is selected in the example of FIG. 6, when a signal arrives from the center of the two directional beams, the level described in the combined delay profile is degraded by about 4 dB from the original level. Value.
[0067]
Therefore, for example, for each timing, the delay profile selecting / combining unit 105 selects two large-level delay profiles from the M delay profiles and adds their level values to generate a composite delay profile. Generate.
[0068]
However, if two delay profiles are always selected for each timing, noise is added when a signal arrives from the peak direction of a certain directional beam or when there is no path. Therefore, the delay profile selection / synthesis unit 105 may set a constraint condition when adding the second level value.
[0069]
As a first method of providing a constraint, when a signal arrives from an intermediate direction between two directional beams, the level value increases in adjacent directional beams. Therefore, when the directional beam of the second level value is adjacent to the first directional beam, a method of adding the second level value is considered.
[0070]
As a second method, there is a method of adding the second level value when the difference between the first and second level values is equal to or smaller than a predetermined value.
[0071]
As a third method, when the first level value is larger than the average noise level of the M delay profiles by a certain level or more, the second level that is within a certain level from the first level value A method of adding values is conceivable.
[0072]
When the number of beam selections is extended to three or more, the same method as the second method can be applied. However, in the above-described second and third methods, the number of directional beams to be combined is excessively large. This is undesirable because noise increases.
[0073]
The path timing detection unit 106 sequentially selects paths having a higher level than the combined delay profile. However, a path selection interval of 0.75 to 1 chip is generally set. That is, a path that is 0.75 to 1 chip before and after the previously selected path is not selected.
[0074]
The initial weight generation unit 107 uses the path timing detected by the path timing detection unit 106 to obtain the path reception units 1091 and 1092 of each path of the reception demodulation unit 108 based on the level information measured by the delay profile selection / combination unit 105. , 109L generate weights used in the initial state (hereinafter, referred to as initial weights).
[0075]
Several methods can be considered for the initial weight generation method of the initial weight generation unit 107.
[0076]
For example, a method is conceivable in which the weight used by the multi-beamformer 103 to form the directional beam having the highest level among the directional beams is used as the initial weight.
[0077]
As another method, a method of judging from a level value ratio between a directional beam having the highest level and a directional beam adjacent thereto and using a weight for forming an intermediate directional beam can be considered. .
[0078]
FIG. 5 is a flowchart showing a specific process of the present method. In FIG. 5, the beam number of the directional beam having the highest level is denoted by B. ₁ , Its level value is P ₁ And B ₁ The beam number of the directional beam having a higher level among the directional beams adjacent to ₂ , Its level value is P ₂ And X is a predetermined threshold.
[0079]
First, the initial weight generation unit 107 determines the level number B ₁ , B ₂ And level value P ₁ , P ₂ Is determined (step 51). Next, the initial weight generation unit 107 ₁ / P ₂ It is determined whether or not ≧ X [dB] (step 52).
[0080]
The initial weight generation unit 107 calculates P ₁ / P ₂ If ≧ X [dB], the beam number B ₁ Is selected (step 53). Also, the initial weight generation unit 107 ₁ / P ₂ <X [dB], beam number B ₁ Directional beam and beam number B ₂ A predetermined weight (intermediate weight) for forming a directional beam (hereinafter, referred to as an intermediate beam) in the middle of the directional beam is set as an initial weight. According to this method, it is possible to easily generate a directional beam with higher accuracy than the resolution of the multi-beamformer 103, that is, an initial weight for forming an intermediate beam. In the case of the orthogonal multi-beam pattern of FIG. 6, the threshold value X is about 9 dB.
[0081]
Since the path receiving units 1091, 1092,..., 109L have the same configuration, the description will focus on only the path receiving unit 1101.
[0082]
The correlator 1101 despreads the spread signals S111, S112,..., S11N at the path timing corresponding to itself, which is detected by the path timing detection unit 106.
[0083]
At the time of the initial operation, the weight adaptation control unit 1131 uses the initial weight given by the initial weight generation unit 107 as it is, and then forms an antenna to form a directional beam for receiving a path included in a multipath from each user. Control weights adaptively. The weight adaptation control unit 1131 adaptively updates the antenna weight using the output of the correlator 1101 and the determination error of the path signal S151, and notifies the beamformer 1111 of the update. As the control operation of the weight adaptive control unit 1131, for example, least mean square error (MMSE) control or the like is used. The MMSE is described in detail in Japanese Patent Application No. 2000-256549.
[0084]
The beamformer 1111 receives each output of the correlator 1101, performs antenna combining with the antenna weight notified from the weight adaptive control unit 1131, and outputs a path signal S151.
[0085]
FIG. 4 is a block diagram showing a configuration of the beam former 1111.
[0086]
The beamformer 1111 includes complex conjugate operation units 4111, 4112, ..., 411N, multipliers 4211, 4212, ..., 421N, and a combiner 431.
[0087]
, 411N perform a complex conjugate operation on the antenna weights input from the weight adaptive control unit 1131.
[0088]
, 421N multiply each output of the correlator 1101 by the complex conjugate of the antenna weight input from the complex conjugate operation units 4111, 4112,.
[0089]
The combiner 431 adds the outputs of the multipliers 4211, 4212,..., 421N and outputs the result as a pass signal S151.
[0090]
Rake combining weighting section 1121 compensates for carrier phase variation in path signal S151, performs weighting for rake combining so that the combined SINR is maximized, and outputs the result as signal sequence S161.
[0091]
The combiner 12 adds the signal sequences S161, S162,..., S16L output from the rake combining weighting units 1121, 1122,..., 112L to generate a high-quality demodulated output.
[0092]
Next, the operation of the present embodiment will be described.
[0093]
First, the path detecting apparatus 101 receives the CDMA signal received by the array antenna, and despreads the CDMA signal of each antenna by the sliding correlator 102. Next, the path detection apparatus 101 uses the multi-beamformer 103 to generate signal sequences S131, S132,... Next, the path detection apparatus 101 uses the beam-by-beam delay profile generation unit 104 to average each of the signal sequences S131, S132,... , S14M are generated. Next, in the path detecting apparatus 101, the delay profile selecting / combining unit 105 measures the levels of the delay profiles S141, S142,..., S14M at each timing, and among them, one or more signals having a large level at each timing. Are selected, and their level values are added to generate a combined delay profile. Next, the path detection apparatus 101 selects a maximum of L paths whose level is greater than the combined delay profile in the path timing detection section 106 and inputs the path timing to the reception demodulation section 108. Further, the path detection apparatus 101 generates an initial weight by the initial weight generation unit 107 from the level information obtained by measuring the level of each of the delay profiles S141, S142,. Input to demodulation section 108.
[0094]
The reception demodulation unit 108 despreads the spread signals S111, S112,..., S11N at each path timing, adaptively controls the antenna weight of the beamformer using the initial weight as an initial value, and generates a directional beam for path reception. Rake-combines the formed and received signal sequences of each path.
[0095]
According to the present embodiment, SINR is directly improved by receiving a directional beam for each despread signal sequence, and path detection is performed by performing path detection based on a combined delay profile generated from a delay profile for each directional beam. Path timing detection characteristics can be realized.
[0096]
Further, according to the present embodiment, the initial weight of the beamformer of each path can be generated from the level information of each directional beam at each path timing obtained for detecting the path timing. Antenna synthesis can be performed with a preferable directional beam.
[0097]
Furthermore, according to the present embodiment, the amount of software operation can be suppressed to the same level as in the past by integrating the multi-beamformer 103 into an IC.
[0098]
【The invention's effect】
According to the present invention, a despread signal sequence of each antenna is received by a plurality of directional beams, and each timing of multipath is detected from a combined delay profile obtained by selectively adding a level value from a delay profile for each directional beam. Therefore, the SINR can be improved and excellent path timing detection characteristics can be realized.
[0099]
Therefore, the initial weight of the directional beam for receiving each path can be generated using the level information indicating the level value of each delay profile at each timing detected when detecting the timing of each path of the multipath. , It is possible to obtain a better antenna combining effect than at the initial time.
[0100]
In addition, by integrating the multi-beamformer into an IC, the amount of software operation can be suppressed to the same level as in the past.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration of an array antenna receiving device according to an embodiment of the present invention.
FIG. 2 is a block diagram showing a configuration of the multi-beamformer of FIG.
FIG. 3 is a block diagram showing a configuration of a beam-by-beam delay profile generator of FIG. 1;
FIG. 4 is a block diagram illustrating a configuration of a beam former of FIG. 1;
FIG. 5 is a flowchart illustrating an example of an initial weight generation method of an initial weight generation unit in FIG. 1;
FIG. 6 is a graph showing an example of a multi-directional beam of a multi-beamformer when the number of directional beams is M = 6 and the number of antennas is N = 6.
FIG. 7 is a graph showing an example of a multi-directional beam of the multi-beamformer 103 when the number of directional beams is M = 12 and the number of antennas is N = 6.
FIG. 8 is a block diagram illustrating a configuration example of a conventional receiving device.
[Explanation of symbols]
101 Path detection device
102 sliding correlator
103 Multi Beam Former
104 Beam-Delay Profile Generation Unit
105 Delay Profile Selection / Synthesis Unit
106 Path timing detection unit
107 Initial weight generator
108 reception demodulation unit
1091,1092, ..., 109L path receiving unit
1101, 1102, ..., 110L correlator
1111,1112, ..., 111L beamformer
1121, 1122,..., 112L Rake synthesis weighting unit
, 113L, weight adaptive control unit
114 Synthesizer
2111 to 211N, 2121 to 212N,..., 21M1 to 21MN multiplier
221, 222, ..., 22M synthesizer
301 In-phase average for each beam
302 Beam level detector
303 Level averaging unit for each beam
4111, 4112, ..., 411N complex conjugate operation unit
4211, 4212, ..., 421N multiplier
431 Synthesizer
S111, S112, ..., S11N Spread signal
S121, S122, ..., S12N Despread signal sequence
S131, S132, ..., S13M signal sequence
S141, S142, ..., S14M delay profile
S151, S152,..., S15L Pass signal
S161, S162, ..., S16L Signal sequence
51-54 steps

Claims (21)

A path detection method for receiving a code division multiple access signal with an array antenna and detecting multipath timing,
Receiving the despread signal sequence of each antenna of the array antenna with a plurality of directional beams,
Generating a delay profile for each directional beam;
At least one delay profile having a large level value is selected for each timing from the delay profile for each directional beam , and when the number of selections of the delay profile is one, the selected level value is used for the selection. If the number is plural, using the sum of the level values of the selected delay profile, generating a combined delay profile;
A path detection method comprising: detecting the timing of the multipath from the combined delay profile. A path receiving directional beam for receiving each path from level information indicating a level value for each timing in the delay profile of each directional beam while detecting the timing of the multipath from the combined delay profile. 2. The path detecting method according to claim 1, wherein an initial value is generated. A path detection device that receives a code division multiple access signal with an array antenna and detects multipath timing,
For each antenna of the array antenna, a despread signal over a plurality of chips, a sliding correlator that outputs a despread signal sequence,
A multi-beamformer that receives the signal sequence output for each antenna with a plurality of directional beams and outputs a signal sequence for each directional beam,
Taking an average of the signal sequence for each of the directional beams at a predetermined time, a beam-by-beam delay profile generating means for generating a delay profile for each of the directional beams,
At least one delay profile having a large level value is selected for each timing from the delay profile for each directional beam , and when the number of selections of the delay profile is one, the selected level value is used for the selection. If the number is plural, a delay profile selecting / synthesizing means for generating a synthetic delay profile by using the sum of the level values of the selected delay profiles;
A path detection device having path timing detection means for detecting the timing of the multipath from the combined delay profile. Initial weight generation means for generating an initial value of an antenna weight for forming a path reception directional beam for receiving each path from level information indicating a level value for each timing in the delay profile of each directional beam. The path detecting device according to claim 3, further comprising: The said delay profile selection / synthesis means selects the delay profile with the largest level value for every timing from the said delay profile for every said directional beam, and makes this level value the level value of the said synthetic delay profile. 5. The path detection device according to 3 or 4. When the number of selections is plural , the delay profile selecting / synthesizing unit selects a delay profile having the largest level value and a delay profile having the second largest level value for each timing from the delay profile for each directional beam. The path detection device according to claim 3, wherein the path detection device selects and adds the level values to generate a combined delay profile. When the number of selections is plural , the delay profile selecting / synthesizing unit sets a delay profile having the largest level value and a delay profile having the second largest level value for each timing of the delay profile for each of the directional beams. 5. The path detection device according to claim 3, wherein, if the directional beams are adjacent directional beams, the second largest level value is added to the largest level value to generate the combined delay profile. When the number of selections is plural , the delay profile selecting / synthesizing unit sets the level value of a plurality of N delay profiles from the largest one to the timing of the delay profile for each directional beam. The path detection device according to claim 3, wherein the combined delay profile is generated by sequentially adding the combined delay profile. The delay profile selecting / synthesizing unit, when the number of selections is plural, for each timing of the delay profile for each directional beam, within a predetermined range from the level value of the delay profile having the largest level value, The path detection device according to claim 3, wherein the combined delay profile is generated by sequentially adding the level values of a plurality of N delay profiles starting from the one with the largest level value. When the number of selections is plural , the delay profile selecting / synthesizing means sets a level value at each timing of the delay profile for each directional beam from an average noise level of the delay profile for each directional beam. 5. The path detection device according to claim 3, wherein the combined delay profile is generated by sequentially adding the level values of a plurality of N delay profiles starting from the one having the largest level value and being the largest. The path detection device according to claim 4, wherein the initial weight generation unit sets a weight of a directional beam having a largest level value from the level information as an initial weight. The initial weight generating means, the level value of the directional beam having the largest level value from the level information, and the level value of the directional beam having the next highest level value in the directional beam adjacent to the directional beam The weight for forming the directional beam having the largest level value or the weight for forming a directional beam intermediate between the directional beam and the adjacent directional beam is defined as an initial weight by the ratio of The path detection device according to claim 4, wherein An array antenna receiving apparatus for receiving a code division multiple access signal by an array antenna and rake combining multipath signals,
For each antenna of the array antenna, a despread signal over a plurality of chips, a sliding correlator that outputs a despread signal sequence,
A multi-beamformer that receives the signal sequence output for each antenna with a plurality of directional beams and outputs a signal sequence for each directional beam,
Taking an average of the signal sequence for each of the directional beams at a predetermined time, a beam-by-beam delay profile generating means for generating a delay profile for each of the directional beams,
At least one delay profile having a large level value is selected for each timing from the delay profile for each directional beam , and when the number of selections of the delay profile is one, the selected level value is used for the selection. If the number is plural, a delay profile selecting / synthesizing means for generating a synthetic delay profile by using the sum of the level values of the selected delay profiles;
Path timing detection means for detecting the timing of the multipath from the combined delay profile,
An initial weight generation unit configured to generate an initial value of an antenna weight for forming a directional beam for path reception for receiving each path from level information indicating a level value for each timing in the delay profile of each directional beam; ,
At least one correlator, corresponding to the timing of the multipath, despreading each spread signal received by the array antenna at the timing;
A beamformer is provided corresponding to the correlator, forms a directional beam for path reception with given antenna weighting, and receives a signal output from the corresponding correlator with the directional beam for path reception. ,
Provided corresponding to the beamformer, the antenna weight is used as the initial value at the time of initial operation, and then the antenna weight is adaptively adjusted using the signal despread by the correlator and the determination error of the beamformer. Weight adaptive control means for updating and giving to the beamformer;
Rake combining weighting means provided corresponding to the beamformer and for weighting the output of the corresponding beamformer so as to compensate for carrier phase fluctuation and maximize SINR after rake combining,
A combiner that adds the outputs of the rake combining weighting means to generate a demodulated output. The said delay profile selection / synthesis means selects the delay profile with the largest level value for every timing from the said delay profile for every said directional beam, and makes this level value the level value of the said synthetic delay profile. 14. The array antenna receiving device according to claim 13. When the number of selections is plural , the delay profile selecting / synthesizing unit selects a delay profile having the largest level value and a delay profile having the second largest level value for each timing from the delay profile for each directional beam. 14. The array antenna receiving apparatus according to claim 13, wherein a combined delay profile is generated by selecting and adding the level values. When the number of selections is plural , the delay profile selecting / synthesizing unit sets a delay profile having the largest level value and a delay profile having the second largest level value for each timing of the delay profile for each of the directional beams. 14. The array antenna receiving apparatus according to claim 13, wherein, when are the directional beams adjacent to each other, the second largest level value is added to the largest level value to generate the combined delay profile. When the number of selections is plural , the delay profile selecting / synthesizing unit sets the level value of a plurality of N delay profiles from the largest one to the timing of the delay profile for each directional beam. 14. The array antenna receiving device according to claim 13, wherein the combined delay profile is generated by sequentially adding. The delay profile selecting / synthesizing unit, when the number of selections is plural, for each timing of the delay profile for each directional beam, within a predetermined range from the level value of the delay profile having the largest level value, 14. The array antenna receiving apparatus according to claim 13, wherein the combined delay profile is generated by sequentially adding the level values of a plurality of N delay profiles starting from the one with the largest level value. When the number of selections is plural , the delay profile selecting / synthesizing means sets a level value at each timing of the delay profile for each directional beam from an average noise level of the delay profile for each directional beam. 14. The array antenna receiving apparatus according to claim 13, wherein the combined delay profile is generated by sequentially adding the level values of a plurality of N delay profiles starting from the one with the largest level value and the largest. 14. The array antenna receiving device according to claim 13, wherein the initial weight generation unit sets a weight of a directional beam having a largest level value from the level information as an initial weight. The initial weight generating means, the level value of the directional beam having the largest level value from the level information, and the level value of the directional beam having the next highest level value in the directional beam adjacent to the directional beam The weight for forming the directional beam having the largest level value or the weight for forming a directional beam intermediate between the directional beam and the adjacent directional beam is defined as an initial weight by the ratio of The array antenna receiving device according to claim 13, wherein:

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