Patent 7676007

Prior art

Earlier patents, publications, and products that may anticipate or render the claims unpatentable.

Active provider: Google · gemini-2.5-flash

Prior art

Earlier patents, publications, and products that may anticipate or render the claims unpatentable.

✓ Generated

To identify the most relevant prior art for US Patent 7676007, I will examine the "Cited By" section of the patent on Google Patents, as this generally includes references considered by the patent examiner. Prior art is information publicly available before a patent's effective filing date that could impact its patentability.

Upon reviewing US Patent 7676007, the "Cited By" section lists several publications and patents. It is crucial to distinguish between "References Cited" (prior art identified during prosecution by the applicant or examiner) and "Cited By" (later patents that cite this patent). For a prior art analysis, we focus on the "References Cited" by US7676007.

The full patent text explicitly incorporates several references by reference. These typically represent prior art that the inventors themselves or the examiner deemed relevant. I will focus on these directly cited references first, as they are explicitly acknowledged within the patent's detailed description.

Here are the most relevant prior art references explicitly mentioned and incorporated by reference within US7676007, along with an analysis of their potential anticipation:

References related to Codebooks for Beamforming (cited in "MIMO-OFDM Systems with Limited Feedback" and "Interpolation of Beamforming Vectors with Quantization" sections):

  • A. Narula, M. J. Lopez, M. D. Trott, and G. W. Wornell, “Efficient use of side information in multiple-antenna data transmission over fading channels,” IEEE J. Select. Areas Commun., vol. 16, no. 8, pp. 1423-1436, Oct. 1998.
    • Publication Date: October 1998
    • Brief Description: This paper discusses the efficient use of side information in multiple-antenna data transmission over fading channels, likely involving the use of codebooks for limited feedback in narrowband MIMO systems.
    • Potential Anticipation (35 U.S.C. § 102): This reference potentially anticipates aspects of claims related to using a codebook for quantizing beamforming vectors in a limited feedback scenario, as generally described in independent claims 1, 19, 25, 28, 40, 41, 42, and 43 where a codebook is mentioned or implied for quantization. Specifically, it could anticipate the concept of quantizing beamforming vectors using a codebook, as mentioned in claim 12 and the general description of limited feedback.
  • D. J. Love and R. W. Heath, Jr., “Equal gain transmission in multi-input multi-output wireless systems,” IEEE Trans. Commun., vol. 51, no. 7, pp. 1102-1110, July 2003.
    • Publication Date: July 2003
    • Brief Description: This paper likely explores "equal gain transmission" in MIMO wireless systems, which is a beamforming technique. It could involve the design or use of beamforming vectors in a feedback system.
    • Potential Anticipation (35 U.S.C. § 102): This reference might anticipate beamforming techniques for MIMO systems, particularly those focused on maximizing gain. It could potentially anticipate aspects of claims 1, 3, 19, 25, 28, 40, 41, 42, and 43 regarding the general concept of beamforming or precoding, especially if "equal gain transmission" is implemented using beamforming vectors similar to those in the patent.
  • D. J. Love, R. W. Heath, Jr., and T. Strohmer, “Grassmannian beamforming for multiple-input multiple-output wireless systems,” IEEE Trans. Inform. Theory, vol. 49, no. 10, pp. 2735-2747, Oct. 2003.
    • Publication Date: October 2003
    • Brief Description: This paper focuses on "Grassmannian beamforming," a specific method for designing beamforming vectors in MIMO systems, often in conjunction with codebooks for limited feedback.
    • Potential Anticipation (35 U.S.C. § 102): This reference directly anticipates the use of Grassmannian precoding, as mentioned in the detailed description ("In another embodiment, the precoding is Grassmannian precoding."). It could anticipate aspects of claims 1, 5, 25, 28, 38, 40, 42, and 43, particularly regarding the use of specific codebook designs or precoding strategies for MIMO systems.
  • K. K. Mukkavilli, A. Sabharwal, E. Erkip, and B. Aazhang, “On beamforming with finite rate feedback in multiple-antenna systems,” IEEE Trans. Inform. Theory, vol. 49, no. 10, pp. 2562-2579, Oct. 2003.
    • Publication Date: October 2003
    • Brief Description: This paper addresses beamforming with finite rate feedback in multiple-antenna systems, directly relevant to the limited feedback aspect of US7676007.
    • Potential Anticipation (35 U.S.C. § 102): This reference is highly relevant as it discusses finite rate feedback for beamforming. It could anticipate the general concept of limited feedback for beamforming vectors in claims 1, 19, 40, and 41, and potentially the use of quantization with a codebook (claims 12, 34) to reduce feedback information.

References related to Spherical Interpolation (cited in "One Embodiment of the Spherical Interpolator 305" section):

  • S. R. Buss and J. P. Fillmore, “Spherical averages and applications to spherical splines and interpolation,” ACM Trans. Graphics, vol. 20, no. 2, pp. 95-126, Apr. 2001.
    • Publication Date: April 2001
    • Brief Description: This paper discusses spherical averages and their applications to spherical splines and interpolation, providing foundational concepts for interpolation on a sphere.
    • Potential Anticipation (35 U.S.C. § 102): This reference anticipates the general concept of spherical interpolation, as mentioned in claims 15 and 38 ("interpolate on a Grassmann manifold," which can be a type of spherical interpolation). However, the patent US7676007 distinguishes itself by introducing a phase rotation parameter for distortion reduction, which is not explicitly covered by this general reference on spherical interpolation.
  • K. Shoemake, “Animating rotation with quaternion curves,” in Proc. SIGGRAPH'85, ACM, San Francisco, July 1985, vol. 19, pp. 245-254.
    • Publication Date: July 1985
    • Brief Description: This paper focuses on animating rotations using quaternion curves, a mathematical technique for interpolating rotations on a sphere.
    • Potential Anticipation (35 U.S.C. § 102): Similar to Buss and Fillmore, this reference provides a method of spherical interpolation (using quaternions). It could anticipate the general concept of spherical interpolation for beamforming vectors (claims 1, 4, 15, 38, 40, 42). Again, the specific innovation of phase rotation in US7676007 would likely differentiate it.
  • G. S. Watson, Statistics on spheres, Wiley, New York, 1983.
    • Publication Date: 1983
    • Brief Description: This book covers statistical methods for data on spheres, which would include interpolation and averaging techniques on spherical manifolds.
    • Potential Anticipation (35 U.S.C. § 102): This book anticipates foundational statistical and interpolation techniques on spheres, broadly covering the mathematical basis for spherical interpolators as used in US7676007. Similar to the other spherical interpolation references, the specific application of phase rotation for distortion reduction in beamforming for MIMO-OFDM is the distinguishing feature of the granted patent.

References related to MRT/MRC (cited in "MIMO-OFDM Systems with Limited Feedback" section):

  • P. A. Dighe, R. K. Mallik, and S. S. Jamuar, “Analysis of transmit-receive diversity in Rayleigh fading,” IEEE Trans. Commun., vol. 51, no. 4, pp. 694-703, Apr. 2003.
    • Publication Date: April 2003
    • Brief Description: This paper analyzes transmit-receive diversity in Rayleigh fading channels, covering concepts like Maximum Ratio Transmission (MRT) and Maximum Ratio Combining (MRC).
    • Potential Anticipation (35 U.S.C. § 102): This reference anticipates the underlying principles of MRT and MRC, which are fundamental to the beamforming and combining strategies in US7676007. It could anticipate aspects of the system where MRT and MRC are used for designing w(k) and z(k), as described in claims 1, 3, 19, 40, and 41, particularly where the receiver uses MRC (claim 19).
  • C.-H. Tse, K.-W. Yip, and T.-S. Ng, “Performance tradeoffs between maximum ratio transmission and switched-transmit diversity,” in Proc. IEEE PIMRC, Sept. 2000, vol. 2, pp. 1485-1489.
    • Publication Date: September 2000
    • Brief Description: This paper compares the performance tradeoffs between MRT and switched-transmit diversity.
    • Potential Anticipation (35 U.S.C. § 102): Similar to the Dighe et al. reference, this work anticipates the core concepts of MRT in communication systems, which forms the basis for transmit beamforming in US7676007. It could anticipate the general use of MRT for transmit beamforming in claims 1, 3, 19, 40, and 41.

It is important to note that while these references describe elements or concepts used in US7676007, the patent often claims a novel combination or modification of these elements, specifically the inclusion of interpolation parameters (phase values) for distortion reduction in beamforming or precoding vectors in a MIMO-OFDM system with partial feedback. Therefore, while individual components might be anticipated, the specific combination and the method of determining and using the phase rotation for interpolation are key to the patent's inventiveness.

Generated 5/25/2026, 6:49:31 PM