JP2010028581A - Wireless communication system, wireless receiving device and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve robustness against changes of an ambient environment. <P>SOLUTION: A system includes: a means 1005 for making wide-angle weights corresponding to a plurality of received beams associated with indexes, and holding them; a means 208 for measuring a quality evaluation value for each received beam; a means 1004 for selecting a first index indicative of a first orientation direction corresponding to a first quality evaluation value having the maximum of a plurality of quality evaluation values; a means 1006 for calculating narrow-angle weights corresponding to a plurality of narrow-angle orientation directions, formed at smaller intervals than angular intervals in a plurality of orientation directions, and using the first orientation direction as a reference; a means 1002 for receiving a signal as a received frame; a means 1002 for acquiring a first multiplication signal by multiplying the narrow-angle weights that are different for at least two different times within one received frame by the received frame; and a means 1003 for selecting a first weight corresponding to the first index and multiplying the first multiplication signal by the first weight to acquire a second multiplication signal. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a radio communication system, a radio reception apparatus, and a method that use a beamforming method.

Some conventional wireless transmission devices are used to transmit signals by selecting one of a plurality of transmission beams that are defined in advance so as to have different directivities. Similarly, some conventional wireless receivers are used to receive a signal by selecting one of a plurality of reception beams defined in advance so as to have different directivities (see, for example, Patent Document 1). .
JP-A-11-55754

  As described above, a conventional technique for selecting a transmission (reception) beam from a plurality of beams defined discontinuously in a direction of departure (DOD) (direction of arrival (DOA) in a radio reception apparatus) area in a radio transmission apparatus. There is a possibility that good characteristics can be obtained in signal transmission in a high frequency channel such as a millimeter wave band to a terahertz band where the contribution of a signal passing through a specific propagation path is large. Similarly, in the wireless reception apparatus, the conventional technique for selecting a reception beam from a plurality of beams defined discontinuously in the direction of arrival (DOA) region is a high frequency in which the contribution of a signal passing through a specific propagation path is large. There is a possibility that good characteristics can be obtained in signal transmission in a channel. The high frequency channel has a very short wavelength (for example, in the case of 60 GHz millimeter wave band, half wavelength λ / 2 = 5 mm), and the complex gain of the channel depends on the positional relationship between the wireless transmission device and the wireless reception device and the surrounding environment. It has the feature of being heavily dependent. Therefore, in the conventional method, there is a problem that the quantized beam defined by discontinuous angles does not always point to the optimum propagation path.

  For the same reason, good characteristics can be obtained when the positional relationship between the wireless transmission device and the wireless reception device and the surrounding environment change during the period from when the beam is selected to when transmission using the beam is terminated. As a result, there is a problem in that the frequency of fallback to the beam search state increases, resulting in a decrease in link throughput.

  The present invention has been made in consideration of the above-described circumstances, and an object thereof is to provide a radio communication system, a radio reception apparatus, and a method that improve robustness against changes in the surrounding environment.

In order to solve the above-described problem, a wireless communication system of the present invention is a wireless communication system including a wireless transmission device and a wireless reception device that receives a signal from the wireless transmission device,
The wireless transmission device includes transmission means for transmitting a plurality of transmission beams having different directivity directions,
The radio reception apparatus includes: a receiving unit that receives the plurality of transmission beams; a measuring unit that measures a transmission beam quality evaluation value for each transmission beam; and a transmission unit that transmits a transmission beam quality evaluation value for each transmission beam. And comprising
The radio transmitting apparatus receives a transmission beam quality evaluation value for each transmission beam, and a first corresponding to the highest transmission beam quality evaluation value of the plurality of transmission beam quality evaluation values. Selection means for selecting a first transmission beam index indicating a directivity direction, holding means for holding a wide-angle weight corresponding to each of the plurality of transmission beams, and the transmission beam index, and the first transmission beam index A first multiplication unit that selects a first weight corresponding to the first weight and multiplies the first weight by a transmission frame to obtain a first multiplication signal, and a plurality of angular intervals in the directivity direction based on the first directivity direction Calculating means for calculating a narrow-angle weight corresponding to each of a plurality of narrow-angle directivity directions formed at a smaller interval, and at least two in one transmission frame The second multiplication means for multiplying the first multiplication signal by different narrow-angle weights at different times to obtain a second multiplication signal, and transmission means for transmitting the second multiplication signal are further provided. And

The wireless communication system of the present invention is a wireless communication system including a wireless transmission device and a wireless reception device that receives a signal from the wireless transmission device,
The wireless transmission device includes transmission means for transmitting a plurality of transmission beams having different directivity directions,
The radio reception apparatus includes: a receiving unit that receives the plurality of transmission beams; a measuring unit that measures a transmission beam quality evaluation value for each transmission beam; and a plurality of the transmission beam quality evaluation values that are ranked in descending order. Generating means for generating the rank information of the transmitted beam, and a transmission means for transmitting the rank information,
The wireless transmission device includes: a receiving unit that receives the rank information; a holding unit that holds a wide-angle weight corresponding to each of a plurality of transmission beams and a directivity direction of the transmission beam; and First multiplication means for selecting a first weight corresponding to the first transmission beam of the highest order among the included transmission beams and multiplying the transmission frame by the first weight to obtain a first multiplication signal; Calculating means for calculating a narrow angle weight corresponding to each of a plurality of narrow angle directivity directions formed at intervals smaller than an angle interval of the plurality of directivity directions with reference to a first directivity direction corresponding to one transmission beam; A second multiplication means for multiplying the first multiplication signal by a different narrow angle weight between at least two different times within one transmission frame to obtain a second multiplication signal; and the second multiplication signal Transmission means for signals to, that further comprises features.

  The radio reception apparatus of the present invention includes a holding unit that holds a wide-angle weight corresponding to each of a plurality of received beams and a received beam index, and a measurement that measures a received beam quality evaluation value for each received beam. Means for selecting a first reception beam index indicating a first directivity direction corresponding to the first reception beam quality evaluation value having the highest value among the plurality of reception beam quality evaluation values, and the first directivity Calculation means for calculating narrow-angle weights corresponding to each of a plurality of narrow-angle directional directions formed at intervals smaller than the angular intervals of the plurality of directional directions on the basis of the direction, and reception for receiving a signal as a reception frame Means for multiplying the received frame by a narrow-angle weight that is different between at least two different times in one received frame to obtain a first multiplied signal. Multiplying means; and second multiplying means for selecting a first weight corresponding to the first reception beam index and multiplying the first multiplication signal by the first weight to obtain a second multiplication signal. It is characterized by.

  According to the wireless communication system, the wireless reception device, and the method of the present invention, it is possible to improve robustness against changes in the surrounding environment.

Hereinafter, a radio communication system, a radio reception apparatus, and a method according to embodiments of the present invention will be described in detail with reference to the drawings. Note that, in the following embodiments, the same numbered portions are assumed to perform the same operation, and repeated description is omitted.
(First embodiment)
The wireless communication system of the present embodiment includes the wireless transmission device 100 of FIG. 1 and the wireless reception device 200 of FIG. The first embodiment is a case where the radio transmission apparatus adjusts the directivity of the transmission beam.
First, the wireless transmission device of this embodiment will be described with reference to FIG.
The radio transmission apparatus 100 according to the present embodiment includes a channel encoding unit 101, an interleaving unit 102, a modulating unit 103, a pilot symbol generating unit 104, a multiplexing unit 105, a receiving antenna 106, a receiving unit 107, a beam order management unit 108, a first A weight holding unit 109, a first weight multiplication unit 110, a second weight calculation unit 111, a second weight multiplication unit 112, and a transmission antenna 113 are included.

Channel coding section 101 outputs a code bit string obtained by performing error correction coding on a data bit string to be transmitted.
Interleaving section 102 acquires a code bit string from channel coding section 101, and outputs a bit string obtained by performing an interleaving process on the code bit string.
Modulation section 103 acquires a bit string from interleaving section 102 and modulates this bit string to generate a modulation symbol (also referred to as a data symbol).
Pilot symbol generation section 104 generates a pilot symbol known to radio receiving apparatus 200 as a communication partner.

  Multiplexing section 105 acquires data symbols from modulating section 103, further acquires pilot symbols from pilot symbol generating section 104, multiplexes the data symbols and pilot symbols with time and frequency, and generates a frame. The multiplexing unit 105 performs time-waveform shaping processing such as a roll-off filter in the case of a single carrier transmission method, and frequency-time conversion processing such as inverse discrete Fourier transform (IDFT) in the case of a multicarrier transmission method. In either method, a signal with a guard interval added is output as necessary.

  The reception unit 107 receives the beam quality evaluation values measured for each transmission beam by the wireless reception device 200 that has received a plurality of transmission beams with different directivity directions from the wireless transmission device 100, and transmits the beam quality evaluation values from the wireless reception device 200 to the reception antenna 106. Receive through. That is, radio receiving apparatus 200 measures the beam quality evaluation value for each transmission beam from radio transmitting apparatus 100 and transmits the beam quality evaluation value that is the measurement result to radio transmitting apparatus 100. Here, the beam quality evaluation value is a signal transmitted using a beam, such as a signal power observed by the radio receiving apparatus 200, a received SNR (Signal to Noise power Ratio), or a received SINR (Signal to Interference plus Noise power Ratio). It is an index representing the reception quality of. The beam quality evaluation value may be a numerical value calculated using one or more of the signal power, the reception SNR, and the reception SINR observed by the radio reception apparatus 200.

The beam order management unit 108 receives the beam quality evaluation values measured for the plurality of transmission beams from the radio transmission apparatus 100 from the radio reception apparatus 200, and the beam quality evaluation values are obtained from the plurality of beam quality evaluation values. The highest transmission beam is selected, and the first transmission beam index l ₁ is assigned to this transmission beam. Further, the beam order management unit 108 determines the second best transmission beam after the first transmission beam (that is, the second highest beam quality evaluation value among the plurality of beam quality evaluation values). , a transmission beam index _l 1, _{l 2} of the # 1 and # 2, the beam quality evaluation value gamma ₁ which corresponds to their associates gamma _2.

The first weight holding unit 109 holds complex weights corresponding to each of the plurality of transmission beams, acquires the _first transmission beam index 11 input from the beam order management unit 108, and transmits this transmission beam. outputting a first weight corresponding to the index l _1.

The first weight multiplication unit 110 distributes the frames acquired from the multiplexing unit 105 to the number of signal lines equal to the number of transmission antennas 113, and multiplies each signal by the weight acquired from the first weight holding unit 109 and outputs the result. . The configuration of the first weight multiplication unit is shown in FIG. In Figure _{3, w 1,1, w 1,2,} ..., w 1, Nt is the first weight from the first weight holding portion _{109, y 1, y 2,} ..., y Nt is the first weight multiplying This is an output signal from the unit 110. When the input signal of the first weight multiplication unit 110 is represented by x and the first weight is represented by w ₁ = [w _1,1 , w ₁ , ₂ ,..., W _{1, Nt} ] ^T , The output signal y = [y ₁ , y ₂ ,..., Y _Nt ] ^T is represented by y = w ₁ ^* x.

The second weight calculation unit 111 receives the first and second transmission beam indexes l ₁ and l ₂ and the corresponding beam quality evaluation values γ ₁ and γ ₂ from the beam order management unit 108, and A second weight is calculated from the value. Details of this calculation will be described later with reference to FIG.

The second weight multiplier 112 multiplies each signal acquired from the first weight multiplier 110 by the second weight acquired from the second weight calculator 111 and outputs the result to the transmission antenna 113. The configuration of the second weight multiplication unit is shown in FIG. In FIG. 4, w _2,1 , w _2,2 ,..., W _{2, Nt} are the second weights from the second weight calculation unit 111, and z ₁ , z _{2 ,.} This is an output signal from the unit 112. When the second weight is represented by w ₂ = [w _2,1 , w _2,2 ,..., W _{2, Nt} ] ^T , the output signal z = [z ₁ , z ₂ ,. z _Nt ] ^T is expressed by z = diag (w ₂ ^* ) y using the output signal y of the first weight multiplier 110. z = diag (w ₂ ^* ) y = diag (w ₂ ^* ) w ₁ ^* x.

As will be described later, the direction of the transmission beam is determined by the first weight w ₁ output from the first weight holding unit 109 and the second weight w ₂ output from the second weight calculation unit 111.

Next, the radio reception apparatus according to the first embodiment will be described with reference to FIG.
The radio reception apparatus 200 according to the present embodiment includes a reception antenna 201, a reception unit 202, a separation unit 203, a channel estimation unit 204, a demodulation unit 205, a deinterleave unit 206, a channel decoding unit 207, a beam quality measurement unit 208, and a transmission unit 209. And a transmit antenna 210.

The reception unit 202 receives a transmission beam from the wireless transmission device 100 by the reception antenna 201, performs reception processing, and acquires a frame included in the transmission beam.
Separating section 203 receives the frame from receiving section 202 and separates this frame into data symbols and pilot symbols. The separation unit 203 also performs guard interval removal, filtering processing such as a roll-off filter, frequency-time conversion processing such as Discrete Fourier Transform (DFT), etc., according to the processing of the multiplexing unit on the transmission side. Apply.

Channel estimation section 204 receives the pilot symbol from demultiplexing section 203 and estimates and outputs a complex gain (channel estimation value) of the channel using this pilot symbol.
The beam quality measurement unit 208 measures the beam quality evaluation value from the propagation path estimation value estimated by the channel estimation unit 204 for each transmission beam.
The transmission unit 209 transmits the beam quality evaluation value for each transmission beam to the wireless transmission device 100 via the transmission antenna 210.

Demodulation section 205 performs channel correction of the data symbols separated by separation section 203 based on the propagation path estimation value estimated by channel estimation section 204, and obtains a bit string.
The deinterleaving unit 206 acquires a bit string from the demodulating unit 205 and performs a deinterleaving process on the bit string to generate a code bit string.
Channel decoding section 207 obtains a code bit string from deinterleaving section 206, and performs error correction decoding on this code bit string to obtain a data bit string.

Next, processing for directing the transmission beam in a desired direction (also referred to as an angle) will be described.
In order to obtain the directivity pattern, it is necessary to consider an array response vector that varies depending on the array shape. A signal transmitted to an angle is represented as v ^T z = v ^T diag (w ₂ ^* ) w ₁ ^* x = xD using an array response vector v = [v ₁ , v ₂ ,..., V _Nr ] ^T. Is done. Here, v _k (k = 1, 2,..., Nr) indicates the response value of the k-th antenna element. This D = v ^T diag (w ₂ ^* ) w ₁ ^* varies depending on the angle and frequency, and a plot of | D | with the angle varied is generally called a directivity pattern.

The array shape includes an equally-spaced linear array, a rectangular planar array, an equally-spaced circular array, and the like, and the corresponding array response vector v is well known in “Adaptive Antenna Technology” (Nobuyoshi Kikuma, Ohm). Further, by manipulating the phase elements constituting the array response vector with w ₁ and w ₂ , the main beam of the beam can be changed to a desired angle. That is, the direction of the transmission beam is determined by the first weight w ₁ output from the first weight holding unit 109 and the second weight w ₂ output from the second weight calculation unit 111.

Next, the definition of the angle of the directional beam will be described with reference to FIG.
As shown in FIG. 5A, a plurality of directional beams are defined. In the example of FIG. 5A, directional beams in eight directions of 0 degrees, 45 degrees, 90 degrees, 135 degrees, 180 degrees, 225 degrees, 270 degrees, and 315 degrees are shown. A directional beam is designated by a beam index l = 0, 1,..., L−1 (L is an integer of 0 or more). The directional beam specified by the beam index l has an angle Θ _l = lΔΘ (where LΔΘ = 360 [degree]). FIG. 5A illustrates the case of L = 8, but of course this is not the case. The beam index is associated with the beam quality evaluation value. For example, a beam having a beam quality evaluation value γ ₁ corresponds to the beam index l ₁ .

Furthermore, in the present embodiment, as shown in FIG. 5B, centering on 0 [degree], M on each of the clockwise side and the counterclockwise side, and the angle of the center are combined to obtain a total of 2M + 1 angles. Defined (where M is an integer of 0 or more). The angle specified by the beam index m = −M, − (M−1),..., −1, 0, 1,..., M−1, M is represented by θ _m = mΔθ. However, 2MΔθ = ΔΘ using the aforementioned ΔΘ.

Conventionally, the beam directivity is controlled only by the beam index l, but in the present invention, the beam index m is used in addition to the beam index l. Thereby, the directivity of the beam can be controlled by the angle Θ _l + θ _m of the total 2M + 1 directional beams having the angle θ _m relative to the angle Θ _l as a center.

Next, when the first weight multiplication unit 110 and the second weight calculation unit 111 calculate and control the transmission beam direction, application of a beam index at the time of frame transmission will be described with reference to FIG.
FIGS. 6A and 6B are frame configurations in the case of multicarrier transmission and single carrier transmission, respectively, including data symbols and pilot symbols. Within the frame, the value of the beam index l remains unchanged within the frame. On the other hand, the beam index m changes. However, when the pilot symbol used by the radio reception apparatus for obtaining the propagation path estimation value necessary for the demodulation of the data symbol is known, a constant beam index m is maintained for the data symbol and the pilot symbol. In the examples of FIGS. 6A and 6B, pilot symbols inserted every three symbol lengths in a frame are used for demodulation of data symbols included in consecutive three symbol times including the symbol timing. The beam index m is constant within three consecutive symbol times including the symbol timing of the pilot symbols.

  Second weight calculation section 111 has a constant value for beam index 1 in the frame, a constant value for beam index m within the period for using the same pilot symbol for demodulation, and a period for using different pilot symbols for demodulation. The second weight is calculated so that the value of m differs between. However, the second weight calculation unit 111 does not need to calculate the second weight so that the value of m is different for all periods during which different pilot symbols are used for demodulation. The second weight calculation unit 111 calculates so as to have different weights between at least two different times in one transmission frame.

Here, theta relative angles when the reference angle a _l, defines those averagely defined in the frame as the centroid theta _C beams. That is, θ _C is an angle from Θ _l . Here, θ _C is signed, and for example, counterclockwise is a positive direction. In this case, θ _m also indicates a similar signed rotation. Furthermore, θ _C is

Here, k (m) is the number of times the beam index m is applied in the frame. That is, the center of gravity θ _C of the beam indicates the direction in which the beam is directed on average.

In the present embodiment, the second weight calculation unit 111 receives the first and second transmission beam indexes l ₁ and l ₂ received from the beam rank management unit 108 and the beam quality evaluation values γ ₁ corresponding to them. The second weight is set using γ ₂ so that the center of gravity θ _C has the following value. θ _C is an angle from Θ ₁₁ . Here, θ _C is signed, and for example, counterclockwise is a positive direction.

That is, the second weight calculator 111 swings the transmission beam uniformly with a width of Δθ around the center of gravity θ _C. In this equation, θ _C represents an angle from the directivity direction, where the directivity direction corresponding to the transmission beam index l ₁ is 0.

In the above description, the centroid is determined by using all the transmission beam indexes l ₁ and l ₂ and the beam quality evaluation values γ ₁ and γ _2. (Modification 1) Using only the transmission beam indexes l ₁ and l ₂ Even if the center of gravity is determined, (Modification 2) The center of gravity may be determined using only the transmission beam index l ₁ .

  In the case of these modified examples, the receiving unit 107 of the wireless transmission device 100 does not need to receive the beam quality evaluation value measured for each transmission beam of the wireless transmission device 100 from the wireless reception device 200, and a plurality of transmission beam qualities. The transmission beam ranking information ranked in descending order of evaluation values may be received from the wireless reception device 200. In this case, radio receiving apparatus 200 generates rank information from a plurality of transmission beam quality evaluation values.

(Modification 1) The center of gravity is determined using only the transmission beam indexes l ₁ and l _2.
The wireless transmission device in this case is the wireless transmission device 700 in FIG. The wireless transmission device 700 is obtained by changing the beam order management unit 108 and the second weight calculation unit 111 in the wireless transmission device 100 to a beam order management unit 701 and a second weight calculation unit 702, respectively.

The beam order management unit 701 receives the beam quality evaluation values measured for the plurality of transmission beams from the radio transmission apparatus 700 from the radio reception apparatus 200, and the beam quality evaluation values are obtained from the plurality of beam quality evaluation values. The highest transmission beam is selected, and the first transmission beam index l ₁ is assigned to this transmission beam. Further, the beam order management unit 701 determines the second best transmission beam next to the first transmission beam (that is, the second highest beam quality evaluation value among the plurality of beam quality evaluation values). To do. However, unlike the beam order management unit 108, the beam order management unit 701 stores the first and second transmission beam indexes l ₁ and l ₂ and the corresponding beam quality evaluation values γ ₁ and γ ₂ . There is no need to associate it.

In this case, the second weight calculation unit 702 sets the weight so that the center of gravity becomes the following value using the _first and _second transmission beam indexes l ₁ and l ₂ received from the beam rank management unit 701. To do.

The upper limit of the center of gravity corresponds to a value in the case of γ ₁ = γ ₂ in the center of gravity setting in the above embodiment. Note that the configurations of the first weight multiplier and the second weight multiplier are the same as those in FIGS. 3 and 4 used in the description of the first embodiment. Further, the discussion on the directivity pattern, the definition of the angle of the directivity beam, the application of the beam index at the time of frame transmission, and the discussion on the center of gravity θ _C of the beam are the same as those in the first embodiment.

(Variation 2) The center of gravity is determined using the transmission beam index l _1.
The wireless transmission device in this case is the wireless transmission device 800 in FIG. The wireless transmission device 800 is obtained by changing the beam order management unit 108 and the second weight calculation unit 111 to a beam order management unit 801 and a second weight calculation unit 802, respectively.

The beam order management unit 801 receives the beam quality evaluation values respectively measured for the plurality of transmission beams from the radio transmission apparatus 800 from the radio reception apparatus 200, and the beam quality evaluation value is determined from the plurality of beam quality evaluation values. The highest transmission beam is selected, and the first transmission beam index l ₁ is assigned to this transmission beam. However, unlike the beam order management unit 108, the beam order management unit 801 does not need to determine the second transmission beam, and further, the first and second transmission beam indexes l ₁ and l ₂ are determined. It is not necessary to associate the beam quality evaluation values γ ₁ and γ ₂ corresponding to them.

In this case, the second weight calculation unit 802 sets weights so that the center of gravity becomes the following value.

This corresponds to the case of γ ₁ >> γ ₂ in the above embodiment. The configurations of the first weight multiplication unit and the second weight multiplication unit are the same as those in FIGS. 3 and 4 used in the description of the first embodiment. Further, the discussion on the directivity pattern, the definition of the angle of the directivity beam, the application of the beam index at the time of frame transmission, and the discussion on the center of gravity θ _C of the beam are the same as those in the first embodiment.

  According to the first embodiment described above, at least using the direction of the transmission beam having the highest beam quality evaluation value among the plurality of beam quality evaluation values in the radio reception apparatus corresponding to the plurality of transmission beams, By obtaining the center of gravity of the beam and directing the transmission beam near the center of gravity, the transmission beam can be directed to a more suitable propagation path, and robustness against changes in the surrounding environment can be improved.

(Second Embodiment)
The wireless communication system of this embodiment includes a wireless transmission device 900 in FIG. 9 and a wireless reception device 1000 in FIG. The second embodiment is a case where the radio reception apparatus adjusts the directivity of the reception beam.
First, the wireless transmission device of this embodiment will be described with reference to FIG.
Radio transmitting apparatus 900 includes channel coding section 101, interleaving section 102, modulating section 103, pilot symbol generating section 104, multiplexing section 105, transmitting section 901, and transmitting antenna 902. Transmitting section 901 transmits, from transmitting antenna 902, a frame obtained by multiplexing data symbols and pilot symbols with time and frequency obtained from multiplexing section 105.

Next, a radio reception apparatus according to the second embodiment will be described with reference to FIG.
The radio reception apparatus 1000 according to the present embodiment includes a reception antenna 1001, a second weight multiplication unit 1002, a first weight multiplication unit 1003, a beam order management unit 1004, a first weight holding unit 1005, a second weight calculation unit 1006, and a separation unit. 203, a channel estimation unit 204, a demodulation unit 205, a deinterleave unit 206, a channel decoding unit 207, and a beam quality measurement unit 208.

  First, the beam order management unit 1004 sequentially outputs a plurality of reception beam indexes corresponding to the number of reception beams that can be realized by the radio reception apparatus 1000 to the first weight holding unit 1005, and weights the second weight calculation unit 1006. A signal to the effect is not output. In each of the plurality of reception beams, the wireless reception device 1000 receives a signal from the wireless transmission device 900, and the beam quality measurement unit 208 measures the quality of the reception signal. Thereafter, the beam order management unit 1004 ranks the plurality of received beams as the highest beam quality evaluation value from the highest received signal quality.

The beam order management unit 1004 outputs the first received beam index l ₁ to the first weight multiplication unit 1003. Also, the beam order management unit 1004 determines the next best received beam (corresponding to the _second received beam index l ₂ ) after the first received beam, and the first and second received beams. The indexes l ₁ and l ₂ and the corresponding beam quality evaluation values γ ₁ and γ ₂ are output to the second weight calculator 1006.

  The first weight holding unit 1005 holds complex weights corresponding to each of the plurality of reception beams, and outputs a weight corresponding to the index input from the beam order management unit 1004. The first weight holding unit 1005 includes a plurality of reception beam indexes corresponding to the number of reception beams that can be realized by the radio reception apparatus 1000, and holds a plurality of complex weights corresponding to the plurality of reception beam indexes.

The second weight multiplying unit 1002 receives the first and second received beam indexes l ₁ and l ₂ and the corresponding beam quality evaluation values γ ₁ and γ ₂ from the beam order management unit 1004, and A second weight is calculated from the value. Details of this calculation will be described later with reference to FIG.

Second weight multiplication section 1002 multiplies each signal acquired from a plurality of reception antennas 1001 by the second weight acquired from second weight calculation section 1006 and outputs the result to first weight multiplication section 1003. The configuration of second weight multiplication section 1002 is shown in FIG. When the input signal is represented by x = [x ₁ , x ₂ ,..., X _Nr ] ^T and the second weight is represented by w ₂ = [w ₂ , ₁ , w ₂ , ₂ ,..., W _{2, Nr} ] ^T , the output The signal y = [y ₁ , y ₂ ,..., Y _Nr ] ^T is represented by y = diag (w ₂ ^* ) x.

The first weight multiplying unit 1003 multiplies each signal input from the second weight multiplying unit 1002 by the weight input from the first weight holding unit 1005 and outputs the result. The configuration of the first weight multiplication unit is shown in FIG. When the first weight is represented by w ₁ = [w _1,1 , w _1,2 ,..., W _{1, Nr} ] ^T , the output signal z is expressed as z = w ₁ ^H using the output y of the second weight multiplier. It is represented by y. z = w ₁ ^H y = w ₁ ^H diag (w ₂ ^* ) x.

Next, a process for directing the reception beam in a desired direction (angle) will be described.
In order to obtain the directivity pattern, it is necessary to consider an array response vector that varies depending on the array shape. Here, if the signal vector input to the receiving antenna is s = [s ₁ , s ₂ ,..., S _Nr ] ^T , the array response vector v = [v ₁ , v ₂ ,..., V _Nr ] ^T is used. It is expressed as s = sv. Here, s = s (t) represents a signal at the phase reference point, and v _k (k = 1, 2,..., Nr) represents a response value of the k-th antenna element. Since this s is equal to x, the array output z = w ₁ ^H diag (w ₂ ^* ) x = sw ₁ ^H diag (w ₂ ^* ) v = sD. This D = w ₁ ^H diag (w ₂ ^* ) v changes depending on the arrival angle and frequency of the signal, and a plot of | D | while changing the arrival angle is generally called a directivity pattern.

The array shape includes an equally-spaced linear array, a rectangular planar array, an equally-spaced circular array, and the like, and the corresponding array response vector v is well known in “Adaptive Antenna Technology” (Nobuyoshi Kikuma, Ohm). Further, by manipulating the phase elements constituting the array response vector with w ₁ and w ₂ , the main beam of the beam can be changed to a desired angle. That is, the direction of the received beam is determined by the first weight w ₁ output from the first weight holding unit 1005 and the second weight w ₂ output from the second weight calculation unit 1006.

Next, when the second weight multiplication unit 1002 and the first weight multiplication unit 1003 calculate and control the reception beam direction, application of a beam index at the time of frame reception will be described with reference to FIG.
FIGS. 6A and 6B are frame configurations in the case of multicarrier transmission and single carrier transmission, respectively, including data symbols and pilot symbols. Within the frame, the value of the beam index l remains unchanged within the frame. On the other hand, the beam index m changes. However, a constant beam index m is maintained for pilot symbols used by the wireless receiver to obtain propagation path estimation values necessary for data symbol demodulation and data symbols corrected by the propagation path estimation values. In the examples of FIGS. 6A and 6B, pilot symbols inserted every three symbol lengths in a frame are used for demodulation of data symbols included in consecutive three symbol times including the symbol timing. The beam index m is constant within three consecutive symbol times including the symbol timing of the pilot symbols.

  The second weight multiplier 1002 has a constant value in the beam index l in the frame, a constant value in the beam index m in the period in which the same pilot symbol is used for demodulation, and a period in which different pilot symbols are used in the demodulation. The second weight is calculated so that the value of m differs between. However, the second weight calculation unit 111 does not need to calculate the second weight so that the value of m is different for all periods during which different pilot symbols are used for demodulation. The second weight calculation unit 111 calculates so as to obtain different weights between at least two different times in one reception frame.

Here, theta relative angles when the reference angle a _l, defines those averagely defined in the frame as the centroid theta _C beams. That is, θ _C is an angle from Θ _l . Here, θ _C is signed, and for example, counterclockwise is a positive direction. In this case, θ _m also indicates a similar signed rotation. Furthermore, θ _C is

Here, k (m) is the number of times the beam index m is applied in the frame. That is, the center of gravity θ _C of the beam indicates the direction in which the beam is directed on average.

In the present embodiment, the second weight calculation unit 1006 receives the first and second received beam indexes l ₁ and l ₂ received from the beam order management unit 1004 and the beam quality evaluation value γ ₁ corresponding to them. , the center of gravity using a gamma ₂ to set the weight to be the following values. θ _C is an angle from Θ ₁₁ . Here, θ _C is signed, and for example, counterclockwise is a positive direction.

That is, the second weight calculation unit 1006 uniformly swings the received beam with a width of Δθ around the center of gravity θ _C.

In the above description, the center of gravity is determined using all of the received beam indexes l ₁ and l ₂ and the beam quality evaluation values γ ₁ and γ _2. (Modification 3) Using only the received beam indexes l ₁ and l ₂ Even if the center of gravity is determined (Modification 4), the center of gravity may be determined using only the received beam index l ₁ .

(Modification 3) The center of gravity is determined using only the reception beam indexes l ₁ and l _2.
The wireless reception apparatus in this case is the wireless reception apparatus 1300 in FIG. The wireless reception device 1300 is obtained by changing the beam order management unit 1004 and the second weight calculation unit 1006 in the wireless reception device 1000 to a beam order management unit 1301 and a second weight calculation unit 1302, respectively.

The beam order management unit 1301 measures the beam quality evaluation values measured for each of the plurality of reception beams with respect to the transmission beam from the radio transmission apparatus 900, and the beam quality evaluation value is the highest among the plurality of beam quality evaluation values. A high received beam is selected, and a first received beam index ₁₁ is assigned to this received beam. Further, the beam order management unit 1301 determines the second best received beam after the first received beam (that is, the second highest beam quality evaluation value among the plurality of beam quality evaluation values). To do. However, unlike the beam order management unit 1004, the beam order management unit 1301 stores the first and second received beam indexes l ₁ and l ₂ and the corresponding beam quality evaluation values γ ₁ and γ ₂ . There is no need to associate it.

In this case, the second weight calculation unit 1302 sets weights so that the center of gravity becomes the following value using the _first and _second received beam indexes l ₁ and l ₂ received from the beam rank management unit 1301. To do.

The upper limit of the center of gravity corresponds to a value in the case of γ ₁ = γ ₂ in the center of gravity setting in the second embodiment. The configurations of the first weight multiplication unit and the second weight multiplication unit are the same as those in FIGS. 12 and 11 used in the description of the second embodiment. Also, the discussion on the directivity pattern, the definition of the angle of the directional beam, the application of the beam index at the time of frame reception, and the discussion on the center of gravity θ _C of the beam are the same as those in the second embodiment.

(Variation 4) The center of gravity is determined using only the received beam index l _1.
The wireless reception device in this case is the wireless reception device 1400 in FIG. The wireless reception device 1400 is obtained by changing the beam order management unit 1004 and the second weight calculation unit 1006 in the wireless reception device 1000 to a beam order management unit 1401 and a second weight calculation unit 1402, respectively.

The beam order management unit 1401 measures the beam quality evaluation values measured for each of the plurality of reception beams with respect to the transmission beam from the wireless transmission apparatus 900, and the beam quality evaluation value is the highest from the plurality of beam quality evaluation values. A high received beam is selected, and a first received beam index ₁₁ is assigned to this received beam. However, unlike the beam order management unit 1004, the beam order management unit 1401 does not need to determine the second received beam, and the first and second received beam indexes l ₁ and l ₂ It is not necessary to associate the beam quality evaluation values γ ₁ and γ ₂ corresponding to.

In this case, the second weight calculation unit 1402 sets weights so that the center of gravity becomes the following value.

This corresponds to the case of the γ ₁ »γ ₂ in the second embodiment described above. The configurations of the first weight multiplication unit and the second weight multiplication unit are the same as those in FIGS. 12 and 11 used in the description of the second embodiment. Also, the discussion on the directivity pattern, the definition of the angle of the directional beam, the application of the beam index at the time of frame reception, and the discussion on the center of gravity θ _C of the beam are the same as those in the second embodiment.

  According to the second embodiment described above, the direction of the reception beam having the highest beam quality evaluation value among the plurality of beam quality evaluation values in the radio reception apparatus using a plurality of reception beams for one transmission beam is determined. By using at least the center of gravity of the beam and directing the reception beam in the vicinity of the center of gravity, the reception beam can be directed to a more suitable propagation path, and robustness against changes in the surrounding environment can be improved. .

(Third embodiment)
The wireless communication system of this embodiment includes the wireless transmission device 100 of FIG. 1 and the wireless reception device 1500 of FIG. The third embodiment is a case where the radio transmission apparatus adjusts the directivity of the transmission beam, and the radio reception apparatus adjusts the directivity of the reception beam.
Since the wireless transmission device of this embodiment is the same as the wireless transmission device 100 of the first embodiment, description thereof is omitted.

  A wireless reception device 1500 according to the present embodiment is obtained by newly adding a transmission unit 209 and a switching unit 1501 to the wireless reception device 1000 according to the second embodiment. As in the wireless reception device 200 in the first embodiment, the wireless reception device 200 that has received each transmission beam from the wireless transmission device 100 wirelessly transmits the beam quality evaluation value measured for each transmission beam. This is necessary when informing the device 100. In this respect, the wireless reception device 1500 is the same as the wireless reception device 200 in the first embodiment. In other respects, the wireless reception device 1500 is the same as the wireless transmission device 100 in the second embodiment.

According to the third embodiment described above, in the wireless transmission device, the direction of the transmission beam having the highest beam quality evaluation value among the plurality of beam quality evaluation values in the wireless reception device corresponding to the plurality of transmission beams is determined. By using at least the center of gravity of the beam and directing the transmission beam near the center of gravity, the transmission beam can be directed to a more suitable propagation path, and robustness against changes in the surrounding environment can be improved. .
Furthermore, according to the third embodiment, the radio reception apparatus has the highest beam quality evaluation value among a plurality of beam quality evaluation values in the radio reception apparatus using a plurality of reception beams for one transmission beam. By using the direction of the received beam at least to determine the center of gravity of the beam and directing the received beam in the vicinity of this center of gravity, the received beam can be directed to a more suitable propagation path, and robustness against changes in the surrounding environment can be achieved. Can be improved.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

1 is a block diagram of a wireless transmission device according to a first embodiment. 1 is a block diagram of a wireless reception device according to a first embodiment. The block diagram of the 1st weight multiplication part of FIG. The block diagram of the 2nd weight multiplication part of FIG. The figure for demonstrating the angle of a directional beam. (A) And (b) is a figure which shows an example of the value of the beam indexes l and m at the time of controlling the transmission or receiving beam direction in the case of multicarrier transmission and the case of single carrier transmission, respectively. The block diagram of the modification 1 of the radio | wireless transmitter of FIG. The block diagram of the modification 2 of the radio | wireless transmitter of FIG. The block diagram of the radio | wireless transmitter of 2nd Embodiment. The block diagram of the radio | wireless receiver of 2nd Embodiment. The block diagram of the 2nd weight multiplication part of FIG. FIG. 11 is a block diagram of a first weight multiplication unit in FIG. 10. FIG. 11 is a block diagram of Modification 3 of the wireless reception device of FIG. 10. FIG. 11 is a block diagram of a fourth modification of the wireless reception device in FIG. 10. The block diagram of the radio | wireless receiver of 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100, 700, 800, 900 ... Wireless transmitter, 101 ... Channel encoding part, 102 ... Interleave part, 103 ... Modulation part, 104 ... Pilot symbol production | generation part, 105 ... Multiplexer 106, receiving antenna 107, 202 ... receiving unit 108, 701, 801, 1004, 1301, 1401 ... beam order management unit 109, 1005 ... first weight holding unit, 110, 1003... First weight multiplier, 111, 702, 802, 1006, 1302, 1402... Second weight calculator, 112, 1002. , 200, 1000, 1300, 1400, 1500 ... wireless receiver, 201, 1001 ... receiving antenna, 203 ... separation 204 ... Channel estimation unit, 205 ... Demodulation unit, 206 ... Deinterleaving unit, 207 ... Channel decoding unit, 208 ... Beam quality measurement unit, 209, 901 ... Transmission unit, 210, 902... Transmitting antenna, 1501.

Claims (19)

A wireless communication system including a wireless transmission device and a wireless reception device that receives a signal from the wireless transmission device,
The wireless transmission device
Comprising transmission means for transmitting a plurality of transmission beams having different directivity directions;
The wireless receiver is
Receiving means for receiving the plurality of transmission beams;
Measuring means for measuring a transmission beam quality evaluation value for each transmission beam;
Transmitting means for transmitting a transmission beam quality evaluation value for each of the transmission beams,
The wireless transmission device
Receiving means for receiving a transmission beam quality evaluation value for each transmission beam;
Selecting means for selecting a first transmission beam index indicating a first directivity direction corresponding to the first transmission beam quality evaluation value having the highest value among the plurality of transmission beam quality evaluation values;
Holding means for holding a wide-angle weight corresponding to each of a plurality of transmission beams and a transmission beam index in association with each other;
First multiplication means for selecting a first weight corresponding to the first transmission beam index and multiplying the transmission frame by the first weight to obtain a first multiplication signal;
Calculating means for calculating a narrow-angle weight corresponding to each of a plurality of narrow-angle directional directions formed at intervals smaller than an angular interval of the plurality of directional directions with respect to the first directional direction;
Second multiplying means for multiplying the first multiplied signal by a different narrow angle weight between at least two different times in one transmission frame to obtain a second multiplied signal;
A wireless communication system, further comprising transmission means for transmitting the second multiplication signal.   The calculation means subtracts the angle in the first directivity direction from the angle in the second directivity direction of the second transmit beam corresponding to the second transmit beam quality evaluation value with the second highest transmit beam quality evaluation value. A value obtained by multiplying the value by the second transmission beam quality evaluation value by the sum of the first transmission beam quality evaluation value and the second transmission beam quality evaluation value is added to the first directivity direction. The wireless communication system according to claim 1, wherein the narrow-angle weight is calculated so that the plurality of narrow-angle directivity directions are distributed around an angle.   The calculation means subtracts the angle in the first directivity direction from the angle in the second directivity direction of the second transmit beam corresponding to the second transmit beam quality evaluation value with the second highest transmit beam quality evaluation value. The narrow angle weight is calculated so that the plurality of narrow angle directivity directions are distributed around an angle obtained by dividing a value by 2 in the first directivity direction. Wireless communication system. A wireless communication system including a wireless transmission device and a wireless reception device that receives a signal from the wireless transmission device,
The wireless transmission device
Comprising transmission means for transmitting a plurality of transmission beams having different directivity directions;
The wireless receiver is
Receiving means for receiving the plurality of transmission beams;
Measuring means for measuring a transmission beam quality evaluation value for each transmission beam;
Generating means for generating transmission beam rank information ranked in descending order of the plurality of transmission beam quality evaluation values;
Transmitting means for transmitting the rank information,
The wireless transmission device
Receiving means for receiving the rank information;
Holding means for holding the wide-angle weight corresponding to each of the plurality of transmission beams and the directivity direction of the transmission beam in association with each other;
First multiplication means for selecting a first weight corresponding to the first transmission beam having the highest order among the transmission beams included in the order information, and multiplying the transmission frame by the first weight to obtain a first multiplication signal. When,
Calculation for calculating a narrow-angle weight corresponding to each of a plurality of narrow-angle directional directions formed at intervals smaller than the angular intervals of the plurality of directional directions, with the first directional direction corresponding to the first transmission beam as a reference Means,
Second multiplying means for multiplying the first multiplied signal by a different narrow angle weight between at least two different times in one transmission frame to obtain a second multiplied signal;
A wireless communication system, further comprising transmission means for transmitting the second multiplication signal.   The calculation means obtains a value obtained by dividing a value obtained by subtracting the angle of the first directivity direction from the angle of the second directivity direction of the second transmit beam of the second position among the transmit beams included in the rank information by 2. The wireless communication system according to claim 4, wherein the narrow-angle weight is calculated so that the plurality of narrow-angle directivity directions are distributed around an angle added to the first directivity direction.   The wireless communication according to claim 1, wherein the calculating unit calculates the narrow-angle weight so that the plurality of narrow-angle directional directions are distributed around the first directional direction. system.   When the pilot symbol necessary for demodulating the data symbol in the frame is known, the calculation means calculates the data symbol and the pilot symbol so as to have the same narrow-angle weight. The wireless communication system according to any one of claims 1 to 6.   The measurement means uses one or more of reception power, reception SNR, and reception SINR of the transmission beam as the transmission beam quality evaluation value. The wireless communication system according to item 1. Holding means for holding a wide-angle weight corresponding to each of a plurality of reception beams and a reception beam index in association with each other;
Measuring means for measuring a received beam quality evaluation value for each received beam;
Selecting means for selecting a first received beam index indicating a first directivity direction corresponding to a first received beam quality evaluated value having the highest value among the plurality of received beam quality evaluated values;
Calculating means for calculating a narrow-angle weight corresponding to each of a plurality of narrow-angle directional directions formed at intervals smaller than an angular interval of the plurality of directional directions with respect to the first directional direction;
Receiving means for receiving a signal as a received frame;
First multiplying means for multiplying the received frame by different narrow-angle weights between at least two different times in one received frame to obtain a first multiplied signal;
Second multiplication means for selecting a first weight corresponding to the first reception beam index and multiplying the first multiplication signal by the first weight to obtain a second multiplication signal. Wireless receiver. Generating means for generating rank information of a plurality of received beams ranked in descending order of the received beam quality evaluation values;
Storage means for associating and storing the received beam index, the received beam quality evaluation value, and the rank information;
The calculation means determines the first directivity direction from the rank information and the second directivity direction of the second receive beam corresponding to the second receive beam quality evaluation value having the second highest receive beam quality evaluation value. And selecting the distribution center of the plurality of narrow angle directivity directions according to the first directivity direction, the second directivity direction, the first received beam quality evaluation value, and the second received beam quality evaluation value. The radio reception apparatus according to claim 9, wherein the narrow-angle weight is calculated.   The calculation means subtracts the angle in the first directivity direction from the angle in the second directivity direction of the second transmission beam corresponding to the second receive beam quality evaluation value having the second highest receive beam quality evaluation value. A value obtained by multiplying the value by the second transmission beam quality evaluation value by the sum of the first transmission beam quality evaluation value and the second transmission beam quality evaluation value is added to the first directivity direction. The radio reception apparatus according to claim 9 or 10, wherein the narrow angle weight is calculated so that the plurality of narrow angle directivity directions are distributed around an angle. Generating means for generating rank information of a plurality of received beams ranked in descending order of the received beam quality evaluation values;
Storage means for storing the received beam index and the rank information in association with each other;
The calculation means determines the first directivity direction from the rank information, and the first directivity direction and a second receive beam quality evaluation value corresponding to a second receive beam quality evaluation value having the second highest value. A second directional direction of the received beam is selected, a distribution center of the plurality of narrow angle directional directions is determined according to the first directional direction and the second directional direction, and the narrow angle weight is calculated. The radio reception apparatus according to claim 9.   The calculation means subtracts the angle in the first directional direction from the angle in the second directional direction of the second received beam corresponding to the second received beam quality evaluated value having the second highest received beam quality evaluated value. The narrow-angle weight is calculated so that the plurality of narrow-angle directional directions are distributed around an angle obtained by dividing a value by 2 in the first directional direction. Item 13. The wireless reception device according to Item 12.   The radio reception apparatus according to claim 9, wherein the calculation unit calculates the narrow-angle weight so that the plurality of narrow-angle directivity directions are distributed around the first directivity direction.   15. The calculation means according to claim 9, wherein the calculation means performs calculation so that a data symbol in a frame and a pilot symbol necessary for demodulating the data symbol have the same narrow-angle weight. The wireless reception device according to any one of the above.   16. The measurement unit according to claim 9, wherein the measurement unit uses at least one of reception power, reception SNR, and reception SINR of the transmission beam as the transmission beam quality evaluation value. The wireless receiver according to item 1. A wireless communication method used in a wireless communication system including a wireless transmission device and a wireless reception device that receives a signal from the wireless transmission device,
In the wireless transmission device,
Transmit multiple transmit beams with different directivity directions,
In the wireless receiver,
Receiving the plurality of transmit beams;
A transmission beam quality evaluation value is measured for each transmission beam;
Transmitting a transmission beam quality evaluation value for each transmission beam;
In the wireless transmission device,
Receiving a transmission beam quality evaluation value for each transmission beam;
Selecting a first transmission beam index indicating a first directivity direction corresponding to a first transmission beam quality evaluation value having the highest value among the plurality of transmission beam quality evaluation values;
A holding means for holding a wide-angle weight corresponding to each of a plurality of transmission beams and a transmission beam index in association with each other is prepared,
Selecting a first weight corresponding to the first transmission beam index, multiplying the transmission frame by the first weight to obtain a first multiplication signal;
Using the first directivity direction as a reference, calculate a narrow-angle weight corresponding to each of a plurality of narrow-angle directivity directions formed at intervals smaller than the angular intervals of the plurality of directivity directions,
Multiplying the first multiplied signal by a different narrow angle weight between at least two different times in one transmission frame to obtain a second multiplied signal;
A wireless communication method, wherein the second multiplication signal is transmitted. A wireless communication method used in a wireless communication system including a wireless transmission device and a wireless reception device that receives a signal from the wireless transmission device,
In the wireless transmission device,
Transmit multiple transmit beams with different directivity directions,
In the wireless receiver,
Receiving the plurality of transmit beams;
A transmission beam quality evaluation value is measured for each transmission beam;
A plurality of transmission beam ranking information ranked in descending order of the transmission beam quality evaluation values,
Sending the ranking information;
In the wireless transmission device,
Receiving the ranking information;
A holding means for holding a wide-angle weight corresponding to each of a plurality of transmission beams and a directivity direction of the transmission beam is prepared,
Selecting a first weight corresponding to the first transmission beam of the highest order among the transmission beams included in the rank information, multiplying the transmission frame by the first weight to obtain a first multiplication signal;
With reference to the first directivity direction corresponding to the first transmission beam, a narrow angle weight corresponding to each of a plurality of narrow angle directivity directions formed at intervals smaller than the angular interval of the plurality of directivity directions is calculated,
Multiplying the first multiplied signal by a different narrow angle weight between at least two different times in one transmission frame to obtain a second multiplied signal;
A wireless communication method, wherein the second multiplication signal is transmitted. A holding means for holding a wide-angle weight corresponding to each of a plurality of reception beams and a reception beam index in association with each other is prepared,
Measure the received beam quality evaluation value for each received beam,
Selecting a first received beam index indicating a first directivity direction corresponding to the highest received beam quality evaluation value of the plurality of received beam quality evaluation values;
Using the first directivity direction as a reference, calculate a narrow-angle weight corresponding to each of a plurality of narrow-angle directivity directions formed at intervals smaller than the angular intervals of the plurality of directivity directions,
Receive the signal as a received frame,
Multiplying the received frame with a different narrow angle weight between at least two different times in one received frame to obtain a first multiplied signal;
A radio reception method comprising: selecting a first weight corresponding to the first reception beam index; and multiplying the first multiplication signal by the first weight to obtain a second multiplication signal.

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