Source: http://www.google.com/patents/US7787824?dq=U.S.+patent+number+7,325,728&ei=Y93TTteOAe702wW6uqi1BQ
Timestamp: 2016-10-23 18:05:23
Document Index: 739788177

Matched Legal Cases: ['art; 204', 'art; 206', 'art; 208', 'art; 210', 'art 606', 'art 606', 'arts 606', 'art 606', 'art 606', 'arts 608', 'art 610', 'art 614', 'art 616', 'art 618', 'arts 1008', 'art 1010', 'art 1012', 'art 1014', 'arts 1016', 'art 1020', 'art 1024', 'art 1026', 'arts 1016', 'art 16', 'art 16']

Patent US7787824 - Receiver, transmission device and receiving method - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inPatentsAn adaptive array antenna part receiving a plurality of transmitted signals in which sub-carrier signal components of predetermined values is suppressed before transmission in order to distinguish a plurality of transmission antenna, by means of the plurality of transmission antennas; a part calculating...http://www.google.com/patents/US7787824?utm_source=gb-gplus-sharePatent US7787824 - Receiver, transmission device and receiving methodAdvanced Patent SearchTry the new Google Patents, with machine-classified Google Scholar results, and Japanese and South Korean patents.Publication numberUS7787824 B2Publication typeGrantApplication numberUS 11/698,050Publication dateAug 31, 2010Priority dateAug 12, 2004Fee statusPaidAlso published asCA2575250A1, CA2575250C, CN1998173A, CN1998173B, EP1777852A1, EP1777852A4, US20070188381, US20100255806, WO2006016409A1Publication number11698050, 698050, US 7787824 B2, US 7787824B2, US-B2-7787824, US7787824 B2, US7787824B2InventorsWladimir Bocquet, Michiharu NakamuraOriginal AssigneeFujitsu LimitedExport CitationBiBTeX, EndNote, RefManPatent Citations (8), Non-Patent Citations (7), Referenced by (3), Classifications (11), Legal Events (2) External Links: USPTO, USPTO Assignment, EspacenetReceiver, transmission device and receiving method
US 7787824 B2Abstract
An adaptive array antenna part receiving a plurality of transmitted signals in which sub-carrier signal components of predetermined values is suppressed before transmission in order to distinguish a plurality of transmission antenna, by means of the plurality of transmission antennas; a part calculating weight factors suppressing the sub-carrier signal components set in the predetermined values, among sub-carrier components included in a received signal; and a part applying the weight factors to the adaptive array antenna means and receiving the plurality of transmitted signals with distinguishing the same are provided.
This application is a U.S. continuation application filed under 35 USC 111 (a) claiming benefit under 35 USC 120 and 365 (c) of PCT application JP04/011602, filed Aug. 12, 2004. The foregoing application is hereby incorporated herein by reference.
[Non-Patent Document 1] A. Van Zelst, “Space division multiplexing algorithm”, Proc. 10th Med. Electrotechnical Conference 2000, pp. 1218-1221; [Non-Patent Document 2] A. Van Zelst et al., “Implementation of a MIMO OFDM based wireless LAN system”, IEEE Trans. Signal. Process. 52, no. 2, 2004, pp. 483-494; and [Non-Patent Document 3] P. W. Wolniansky et al., “V-BLAST: An architecture for realizing very high data rates over the rich scattering wireless channel”, in Proc. Int. Symposium on Advanced Radio Technologies, Boulder, Colo., September 1998. SUMMARY OF THE INVENTION
Received signals can be separated into respective ones of a plurality of transmitted signals by means of these various methods. However, a required operation burden is not so light when any method is adopted. Generally speaking, a signal separation accuracy and a signal estimation accuracy increase in the stated order of the first through fifth methods. However, an operation burden required for signal processing also tends to increase. Especially, the fifth method requires distance calculation for all the possible signal point combination number, i.e., a combination number as large as (the number of possible symbol mapping signal points)(the number of transmission antennas). Thus, a very heavy operation burden is required. When the first method is adopted, an operation burden required for obtaining an inverse matrix is not so light. Accordingly, although a communication system of the MIMO method or combining the MIMO method and another method has properties which are hopeful in future, a problem is that a heavy operation burden is required for distinguishing the plurality of transmitted signals transmitted from the plurality of transmission antennas simultaneously. This fact causes disadvantageousness especially for such a product application as those for a cellular phone or a handy mobile terminal.
FIG. 1 shows a general outline of a radio communication system in a MIMO method.
202 serial to parallel conversion part; 204 inverse fast Fourier transform part; 206 parallel to serial conversion part; 208 guard interval adding part; 210 transmission antenna;
According to an embodiment of the present invention, a plurality of transmitted signals transmitted from a plurality of transmission antennas are received by an adaptive array antenna part. The plurality of transmitted signals are distinguished from each other by a positional relationship of sub-carrier set that have predetermined values before transmission. Weight factors suppressing signal components of the sub-carrier set that is associated to the transmitted signal that is being distinguished are calculated. The weight factors are applied to the adaptive array antenna part, then the directivity is formed so that the one or plurality of transmitted signals other than the transmitted signal that is being distinguished are suppressed.
FIG. 6 shows a general outline of a receiver in one embodiment of the present invention. In the embodiment, the MIMO method and the OFDM method are adopted. As to a transmitter, a configuration shown in FIG. 4 may be adopted. For the purpose of simplification, it is assumed that the transmitter has two transmission antennas, and, therefrom, two types of transmitted signals x1 and x2 are transmitted simultaneously at the same frequency. The receiver shown in FIG. 6 has a plurality of (NA) antenna elements 602-1 through NA, NA guard interval removing parts (-GI) 604-1 through NA, a first signal separating part 606-1, a second signal separating part 606-2. The first and second signal separating parts 606-1, 2 have substantially the same configuration, and description therefor is made for the first signal separating part 606-1 as a representative. The first signal separating part 606-1 has NA weight multiplying parts 608-1 through NA, an adding part 610, a fast Fourier transform part (FFT) 612, a channel compensation part 614, a demodulation part 616 and a weight control part 618.
In the transmitted signals of the OFDM method, data is mapped to the plurality of sub-carriers, and inverse fast Fourier transform is carried out. Thereby, demodulation in the OFDM method is carried out. Each sub-carrier is spaced mutually by a multiple of a reciprocal of 1 symbol period, and the sub-carriers have such a positional relationship that they are mutually orthogonal. Accordingly, the transmitted signals x1, x2 have many frequency components (sub-carrier components) on a frequency axis as shown in the top half of FIG. 8. However, data is not mapped to some sub-carriers such as the p-th sub-carrier concerning the transmitted signal x1, and the q-th sub-carrier concerning the second transmitted signal x2. These sub-carriers not used in data transmission (called ‘virtual sub-carriers’) are set for the purpose of, for example, suppressing DC offset components, avoiding interference from adjacent bands, or such. The positions of the sub-carries not used in data transmission may be determined according to a standard, may be determined by a system operator, or may be determined from another view point. In any method, the fact that these sub-carriers are not used in data transmission should be known by both of the transmission and reception sides, and the plurality of transmitted signals should be distinguishable from the positional relationship of the virtual sub-carriers.
There, i denotes a parameter indicating the number of iterating times, λ denotes a forgetting factor having a value of 0.995 or such, wH denotes a conjugate transposed vector of a vector having components of the weight factors, and Rp denotes an amount indicating the p-th sub-carrier component. For a method of calculating the weight factors, known technology such as a minimum mean squire error method such as a recursive least squire (RLS) method, a least means squire (LMS) method, or such, may be utilized. The weight factors used for the adaptive array antenna are calculated based on knowledge concerning the virtual sub-carriers when the correspondence relationship between the transmitted signals and the virtual sub-carriers (sub-carriers to which data is not mapped) is known.
FIG. 10 shows a partial block diagram of a receiver in one embodiment of the present invention. The receiver according to the embodiment is used in a system combining the MIMO method, the OFDM method and the code division multiplexing (CDMA) method. It is noted that, for the purpose of simplification, only a part concerning a first transmitted signal x1 and a first received signal y1 is shown. As to a transmitter, it is possible to utilize a common transmitter (not shown) adopting the MIMO method, the OFDM method and the CDMA method. The receiver shown in FIG. 10 includes a plurality of (NA) antenna elements 1004-1 through NA, NA weight multiplying parts 1008-1 through NA, an adding part 1010, a fast Fourier transform (FFT) part 1012, a channel compensation part 1014, several sub-carriers' multiplying parts 1016, 1018, a combining part 1020, a parallel to serial conversion part (P/S) 1022, a demodulation part 1024, and a weight control part 1026. For the purpose of convenience of showing in the figure, the several sub-carries' multiplying parts 1016 and 1018 are shown as having all the same reference numerals.
The examples described in the embodiments 1 and 2 use the communication systems adopting the multi-carrier method. Some of the plurality of sub-carriers are set as the virtual sub-carriers, the virtual sub-carrier components in the received signals are suppressed, and thus, the adaptive array antenna is adjusted in such a manner that the transmitted signals are distinguishable when the transmitted signals are received. Accordingly, it is not possible to apply this art to a communication system in a conventional single carrier method without any modification thereof. Below, an embodiment of applying the present invention to the MIMO method of the signal-carrier type will be described.
In the embodiments 1 through 3, the directivity of the adaptive array antenna is controlled while the sub-carrier component (for example, the p-th sub-carrier component for the first transmitted signal) which is the part of the received signals is suppressed. In the present embodiment, weight factors are calculated in such a manner that all the sub-carrier components of signals received during a certain period are suppressed.
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS6441786Jul 20, 2001Aug 27, 2002Motorola, Inc.Adaptive antenna array and method for control thereofUS7352819 *Dec 24, 2003Apr 1, 2008Intel CorporationMultiantenna communications apparatus, methods, and systemUS7463577 *Apr 9, 2003Dec 9, 2008Panasonic CorporationOFDM communication method and OFDM communication deviceUS20020191535Apr 5, 2002Dec 19, 2002Nippon Telegraph And Telephone CorporationOFDM signal communication system, OFDM signal transmitting device and OFDM signal receiving deviceUS20040135723Dec 23, 2003Jul 15, 2004Yuuta NakayaAdaptive array antenna controllerJP2003060604A Title not availableJP2003124907A Title not availableJP2004214857A Title not available* Cited by examinerNon-Patent CitationsReference1A. Van Zelst, "Space Division Multiplexing Algorithm," Proc. 10th Med., Electrotechnical Conference 200, pp. 1218-1221. MEIecon 2000.2A. Van Zelst, et al., "Implementation of a MIMO OFDM Based Wireless LAN System," IEEE Trans. Signal. Process. 52, No. 2, 2004, pp. 483-494.3A. Van Zelst, et al., "Implementation of a MIMO OFDM Based Wireless LAN System," IEEE Trans. Signal. Process. 52, No. 2, 2004; pp. 483-494.4 *Hara et al, Capacity enhancement by virtual subcarrier assignment for OFDM-based wireless system, May 17, 2004, IEEE, vol. 3, pp. 1811-1815.5IEEE Std. 802. 16a-2003 dated Apr. 1, 2003. IEEE Standard for Local and metropolitan area networks Part 16: Air Interface for Fixed Broadband Wireless Access Systems- Amendment 2: Medium Access Control Modifications and Additional Physical Layer Specifications for 2-11 GHz.6IEEE Std. 802. 16a-2003 dated Apr. 1, 2003. IEEE Standard for Local and metropolitan area networks Part 16: Air Interface for Fixed Broadband Wireless Access Systems— Amendment 2: Medium Access Control Modifications and Additional Physical Layer Specifications for 2-11 GHz.7P.W. Wolniansky, et al., "V-BLAST: An Architecture for Realizing Very High Data Rates Over the Rich Scattering Wireless Channel," Proc. Int. Symposium on Advanced Radio Technologies, Boulder, CO, Sep. 1998.* Cited by examinerReferenced byCiting PatentFiling datePublication dateApplicantTitleUS8553521Sep 25, 2006Oct 8, 2013Interdigital Technology CorporationMIMO beamforming-based single carrier frequency division multiple access systemUS9184808Oct 7, 2013Nov 10, 2015Interdigital Technology CorporationMimo beamforming-based single carrier frequency division multiple access systemUS20100246377 *Sep 25, 2006Sep 30, 2010Interdigital Technology CorporationMimo beamforming-based single carrier frequency division multiple access system* Cited by examinerClassifications U.S. Classification455/59, 370/208, 455/61, 370/334, 455/562.1International ClassificationH04J99/00, H04K3/00, H04B7/00Cooperative ClassificationH04B7/086, H04B7/0413European ClassificationH04B7/08C4PLegal EventsDateCodeEventDescriptionApr 20, 2007ASAssignmentOwner name: FUJITSU LIMITED, JAPANFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:BOCQUET, WLADIMIR;NAKAMURA, MICHIHARU;REEL/FRAME:019216/0592;SIGNING DATES FROM 20070104 TO 20070120Owner name: FUJITSU LIMITED, JAPANFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:BOCQUET, WLADIMIR;NAKAMURA, MICHIHARU;SIGNING DATES FROM20070104 TO 20070120;REEL/FRAME:019216/0592Jan 29, 2014FPAYFee paymentYear of fee payment: 4RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services