Source: http://www.google.com/patents/US20020196734?ie=ISO-8859-1
Timestamp: 2014-09-19 15:12:17
Document Index: 727311026

Matched Legal Cases: ['art 150', 'art 150', 'art 150', 'art 150', 'art 150', 'art 150', 'art 150']

Patent US20020196734 - OFDM transmission system transceiver and method - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign in<nobr>Advanced Patent Search</nobr>PatentsAn OFDM system transceiver for transmitting frequency dividing data in parallel includes antenna elements for receiving known reception and reception data signals. The FFTs transform the known reception signals and the reception data signals to obtain known reception sub-carrier signals and reception...http://www.google.com/patents/US20020196734?utm_source=gb-gplus-sharePatent US20020196734 - OFDM transmission system transceiver and methodAdvanced Patent SearchPublication numberUS20020196734 A1Publication typeApplicationApplication numberUS 10/160,097Publication dateDec 26, 2002Filing dateJun 4, 2002Priority dateJun 7, 2001Also published asUS7113548Publication number10160097, 160097, US 2002/0196734 A1, US 2002/196734 A1, US 20020196734 A1, US 20020196734A1, US 2002196734 A1, US 2002196734A1, US-A1-20020196734, US-A1-2002196734, US2002/0196734A1, US2002/196734A1, US20020196734 A1, US20020196734A1, US2002196734 A1, US2002196734A1InventorsMakoto Tanaka, Kazuoki MatsugataniOriginal AssigneeMakoto Tanaka, Kazuoki MatsugataniExport CitationBiBTeX, EndNote, RefManReferenced by (36), Classifications (13), Legal Events (3) External Links: USPTO, USPTO Assignment, EspacenetOFDM transmission system transceiver and methodUS 20020196734 A1Abstract An OFDM system transceiver for transmitting frequency dividing data in parallel includes antenna elements for receiving known reception and reception data signals. The FFTs transform the known reception signals and the reception data signals to obtain known reception sub-carrier signals and reception data sub-carrier signals. The estimator estimates propagation path estimating values of each of the reception data sub-carrier signals with respect to each of the known reception sub-carrier signals. The weight calculator calculates a maximum ratio composition weight to composite the reception data sub-carrier signals. The setting means sets a transmission weight based on the maximum ratio composition weight. The generator generates a transmission data signal by arranging transmission sub-carrier signals on the frequency axis. The multipliers multiply the transmission data signals by the transmission weight and output the multiplied resultant to the respective antenna elements. Images(9) Claims(19)
[0055] P  ( ∫ , k ) = ∑ i = 1 M   hi  ( ∫ , k )  2 ( 4 ) [0056] Incidentally, as shown in mathematical expression (2), each of the denominators uniformly scales the composition signals z(f, k) with respect to the respective data sub-carrier signals. [0057] Next, the maximum value Pmax of the additional value P(f, k) is calculated. The maximum value Pmax indicates sub-carrier signals with maximum signal levels of all received known sub-carrier signals. Accordingly, elements of the maximum ratio composition weight W corresponding to the maximum value Pmax is a weight with the highest reliability of the additional values P. Further, a column order of the maximum value Pmax is calculated, and thereafter respective elements of maximum ratio composition weight W corresponding to the maximum value Pmax with the column order are selected as transmission weight Wtx (selector). [0058] When column order �n� is selected, because the maximum ratio composition weight W is expressed as mathematical expression (5) using polar coordinates, the weight Wt is expressed as mathematical expression (6). W = ( A 11  exp  ( j * θ 11 ) A 11  exp  ( j * θ 12 ) ⋯ A 11  exp  ( j * θ 1  k ) A 21  exp  ( j * θ 21 ) A 22  exp  ( j * θ 22 ) ⋯ A 2  k  exp  ( j * θ 2  k ) ⋮ ⋮ ⋮ A i1  exp  ( j * θ i1 ) A i2  exp  ( j * θ i2 ) ⋯ A ik  exp  ( j * θ ik ) ) ( 5 ) Wt = ( A 1  n  exp  ( j * θ 1  n ) A 2  n  exp  ( j * θ 2  n ) ⋮ A i   n  exp  ( j * θ i   n ) ) ( 6 ) [0059] Subsequently, the phases are drawn from the weight Wt by removing the amplitudes to enable transmission weight Wtx to be calculated as shown in mathematical expression (7). The transmission weight Wtx is standardized by the standardizing part 150. Further, the standardizing part 150 outputs the standardized transmission weight Wtx to the multipliers 160-163, and it is set at the multipliers 160-163 (output means). Wtx = ( exp  ( j * θ 1  n ) exp  ( j * θ 2  n ) ⋮ exp  ( j * θ i   n ) ) ( 7 ) [0060] In this way, the weight selector 140 selects the transmission weight Wtx based on the maximum ratio composition weight W. Also, the transmission weight Wtx is set at the multipliers 160-163. Accordingly, it is possible to simply and easily form the transmission beam. [0061] (Second Embodiment) [0062] In the second embodiment, an average of at least two elements of maximum ratio composition weight W is used as transmission weight Wtz. Specifically, a weight selector 140 selects the transmission weight Wtz as follows. [0063] First, respective elements P (f, k) of vector P are arranged based on their respective scaled values. Thereafter, n parts of the elements that are larger than the other elements are selected, thereby selecting n parts of the elements with the highest reliability. [0064] Next, matrices corresponding to the selected n parts of the elements are chosen from the maximum ratio composition weight W. The chosen elements are shown in the matrix form of (n)�(number of the sub-carrier signals) as mathematical expression (8). WR = (  h 1  ( ∫ , 1 )  h 1  ( ∫ , 1 )  2 h 1  ( ∫ , 16 )  h 1  ( ∫ , 16 )  2 h 1  ( ∫ , 32 )  h 1  ( ∫ , 32 )  2 h 1  ( ∫ , 37 )  h 1  ( ∫ , 37 )  2 h 2  ( ∫ , 1 )  h 2  ( ∫ , 1 )  2 h 2  ( ∫ , 16 )  h 2  ( ∫ , 16 )  2 h 1  ( ∫ , 32 )  h 1  ( ∫ , 32 )  2 h 2  ( ∫ , 37 )  h 2  ( ∫ , 37 )  2 ⋮ ⋮ ⋮ ⋮ h i  ( ∫ , 1 )  h i  ( ∫ , 1 )  2 h i  ( ∫ , 16 )  h i  ( ∫ , 16 )  2 h i  ( ∫ , 32 )  h i  ( ∫ , 32 )  2 h i  ( ∫ , 32 )  h i  ( ∫ , 37 )  2  ) ( 8 ) [0065] In mathematical expression (8), orders k of the n parts of the sub-carrier signals are, for example, 1, 16, 32 and 37 (k=1, 16, 17, 32). [0066] Further, a weight Wtt shown in mathematical expression 9 is calculated by respectively adding the same column (the same sub-carrier) elements of the matrix WR. The weight Wtt includes elements of respective antenna elements 10-13. Also, the phases are drawn from the weight Wtt by removing the amplitudes to enable the transmission weight Wta to be calculated as shown in mathematical expression 7. Thus, the transmission weight Wta is standardized by a standardizing part 150. The standardizing part 150 outputs the standardized transmission weight Wta to the multipliers 160-163, and it is set at multipliers 160-163. k = 2 , 16 , 33 , 37 Wtt = ( ∑ k  h 1  ( ∫ , 1 )  h 1  ( ∫ , 1 )  2 ∑ k  h 2  ( ∫ , 1 )  h 2  ( ∫ , 1 )  2 ⋮ ∑ k  h i  ( ∫ , 1 )  h i  ( ∫ , 1 )  2 ) = ( B 1  ∫ exp  ( j * θ 1 ∫ ) B 2  ∫ exp  ( j * θ 2 ∫ ) ⋮ B i  ∫ exp  ( j * θ i ∫ ) ) ( 9 ) Wta = ( exp  ( j * θ 1 ∫ ) exp  ( j * θ 2 ∫ ) ⋮ exp  ( j * θ i ∫ ) ) ( 10 ) [0067] (Third Embodiment) [0068] In the third embodiment, a transmission weight is set with respect to respective antenna elements 10-13 and respective sub-carrier signals. [0069] Referring to FIG. 5, a transmitter 2A is adopted instead of the transmitter 2 of the first embodiment. The transmitter 2A has an S/P converter 100, a modulator 110A, iFFTs 170-173, P/S converters 180-183, a weight selector 140A, a standardizing part 150A and multipliers 160A-163A. Incidentally, the other elements in FIG. 5 are basically the same as the elements in FIG. 1. [0070] In the transmitter 2A, the S/P converter 100 converts serial modulation data into parallel signals. The modulator 110A digitally modulates the parallel signals and outputs modulated data. The multipliers 160A-163A multiply transmission weight by the modulated data and output multiplied signals to the respective iFFTs 170-173. [0071] The iFFTs 170-173 inverse Fourier-transform the multiplied signals into transmission data signals. The transmission data signals include frequency domain transmission sub-carrier signals. In the present third embodiment, the multiplied signals are adopted as the transmission sub-carrier signals. [0072] The P/S converters 180-183 convert the parallel transmission signals into serial signals and output them to the antenna elements 10-13 through the switches 90-93. The weight selector 140A selects transmission weight by a maximum ratio composition weight W. The standardizing part 150A standardizes amplitudes of the selected transmission weight based on a dynamic range of the transmitter 2A and outputs the standardized transmission weight. [0073] In the transmitter 2A the weight selector 140A outputs only phases of the maximum ratio composition weight W to the multipliers 160-163 as the transmission weight Wtz shown in mathematical expression (11). Therefore, the transmission weight Wtz is set at respective transmission sub-carrier signals. Wtz = ( exp  ( j * θ 11 ) exp  ( j * θ 12 ) ⋯ exp  ( j * θ 1  k ) exp  ( j * θ 21 ) exp  ( j * θ 22 ) ⋯ exp  ( j * θ 2  k ) ⋮ ⋮ ⋮ exp  ( j * θ i1 ) exp  ( j * θ i2 ) ⋯ exp  ( j * θ i   k ) ) ( 11 ) [0074] Accordingly, the P/S converter 130 converts the parallel transmission signals into serial signals and outputs them to the antenna elements 10-13 via switches 90-93. Thus, the transmission beams of the antennas 10-13 are formed. [0075] (Modifications) [0076] The above described embodiments of the present invention may be modified without departing from the spirit or scope of the present invention. For example, in the first embodiment, the phases are drawn from the weight Wt by removing the amplitudes to calculate the transmission weight Wtx. However, the weight Wt can be set at the multipliers 160-163 instead of at the transmission weight Wtx. In this case, not only phases of the weight Wt but also amplitudes thereof are set at the multipliers 160-163. [0077] In the second embodiment, the transmission weight Wta is set at the multipliers 160-163 through the standardizing part 150. However, the weight Wtt can be set at multipliers 160-163 instead of the transmission weight Wta. In this case, not only phases of the weight Wtt but also amplitudes thereof are set at the multipliers 160-163. [0078] In the third embodiment, only phases of the maximum ratio composition weight W are output to the multipliers 160-163 as the transmission weight Wtz. However, a transmission weight Wty can be adopted instead of the transmission weight Wtz. That is, inverse numbers of respective elements of the vector P shown in the mathematical expression 3 may be calculated and multiplied by scaling factor a to calculate a vector B shown in mathematical expression (12). B = ( α 1 P  ( ∫ , 1 ) α 2 P  ( ∫ , 1 ) ⋯ α k P  ( ∫ , 1 ) )  ( 12 ) [0079] Further, as shown in mathematical expression (13), the vector B is multiplied by the transmission weight Wtz shown in mathematical expression (11). The multiplied resultant is used as the transmission weight Wty and is output to the multipliers 160-163. Wty = ( exp  ( j * θ 11 ) exp  ( j * θ 12 ) ⋯ exp  ( j * θ 1  k ) exp  ( j * θ 21 ) exp  ( j * θ 22 ) ⋯ exp  ( j * θ 2  k ) ⋮ ⋮ ⋮ exp  ( j * θ i1 ) exp  ( j * θ i2 ) ⋯ exp  ( j * θ i   k ) ) � dial  ( B ) ( 13 ) [0080] While the above description is of the preferred embodiments of the present invention, it should be appreciated that the invention may be modified, altered, or varied without deviating from the scope and fair meaning of the following claims. 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