Beamforming in antenna systems
Gespeichert in:
| Titel: | Beamforming in antenna systems |
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| Patent Number: | 9,967,014 |
| Publikationsdatum: | May 08, 2018 |
| Appl. No: | 15/347027 |
| Application Filed: | November 09, 2016 |
| Abstract: | Apparatuses, methods, and systems for beamforming in antenna systems are disclosed. A method includes determining an unconstrained analog precoding matrix (FRF,UC), wherein the unconstrained analog precoding matrix (FRF,UC) is determined based on M dominant eigenvectors of the sum of spatial channel covariance matrices of K users, and wherein K indicates a number of users communicating with a base station. The method further includes determining a constrained analog precoding matrix (FRF) based on the unconstrained analog precoding matrix (FRF,UC), determining a compensation matrix (FCM), digitally multiplying K inputs with a multiple-input multiple-output (MIMO) precoding matrix (FMU) generating M outputs, digitally multiplying the M outputs with the compensation matrix (FCM) generating M compensation outputs, generating M analog frequency-up-converted signals based on the M compensation outputs, and analog multiplying the M analog frequency-up-converted signals with the analog precoding matrix (FRF) generating N output signals for transmission, wherein N is greater than M. |
| Inventors: | Facebook, Inc. (Menlo Park, CA, US) |
| Assignees: | Facebook, Inc. (Menlo Park, CA, US) |
| Claim: | 1. A base station, comprising: baseband precoding circuitry, wherein the baseband precoding circuitry receives K inputs and digitally multiplies the K inputs with a multiple-input multiple-output (MIMO) precoding matrix (F MU) generating M outputs, and wherein K indicates a number of users communicating with the base station; a compensation circuitry, wherein the compensation circuitry digitally multiplies the M outputs of the baseband precoding circuitry with a compensation matrix (F CM) generating M compensation outputs; M radio frequency (RF) chains, wherein each RF chain is configured to receive one of the M compensation outputs, and generate an analog frequency-up-converted signal; and analog precoding circuitry, wherein the analog precoding circuitry receives the M analog frequency-up-converted signals and analog multiplies the M analog frequency-up-converted signals with a constrained analog precoding matrix (F R) generating N output signals for transmission, wherein N is greater than M; wherein the constrained analog precoding matrix (F RF) is determined based on an unconstrained analog precoding matrix (F RF,UC), and wherein the unconstrained analog precoding matrix (F RF,UC) is determined based on dominant eigenvectors of the sum of spatial channel covariance matrices of the K users; and wherein the compensation matrix (F CM) is determined based on the constrained analog precoding matrix (F RE). |
| Claim: | 2. The base station of claim 1 , wherein K is less than or equal to M. |
| Claim: | 3. The base station of claim 1 , wherein multiplication of the unconstrained analog precoding matrix (F RF,UC) with any invertible matrix is substantially equal to the constrained analog precoding matrix (F RF). |
| Claim: | 4. The base station of claim 1 , wherein the MIMO precoding matrix (F MU) is determined based on an effective channel matrix that comprises one or more of the constrained analog precoding matrix (F RF), the compensation matrix (F CM), and a raw channel matrix. |
| Claim: | 5. The base station of claim 1 , wherein the constrained analog precoding circuitry comprises phase shifters, and wherein the analog multiplication of the unconstrained analog precoding matrix (F RF,UC) controls phases of the analog frequency-up-converted signals. |
| Claim: | 6. The base station of claim 1 , wherein the constrained analog precoding circuitry comprises phase shifters, wherein multiplication of the constrained analog precoding matrix (F RF) and the compensation matrix (F CM) is substantially equal to the unconstrained analog precoding matrix (F RF,UC). |
| Claim: | 7. A method, comprising: determining an unconstrained analog precoding matrix (F RF,UC), wherein the unconstrained analog precoding matrix (F RF,UC) is determined based on M dominant eigenvectors of the sum of spatial channel covariance matrices of K users, and wherein K indicates a number of users communicating with a base station; determining a constrained analog precoding matrix (F RF) based on the unconstrained analog precoding matrix (F RF,UC); determining a compensation matrix (F CM), wherein the compensation matrix (F CM) is determined based on the constrained analog precoding matrix (F RF); digitally multiplying K inputs with a multiple-input multiple-output (MIMO) precoding matrix (F MU) generating M outputs; digitally multiplying the M outputs with the compensation matrix (F CM) generating M compensation outputs; generating M analog frequency-up-converted signals based on the M compensation outputs; and analog multiplying the M analog frequency-up-converted signals with the analog precoding matrix (F RF) generating N output signals for transmission, wherein N is greater than M. |
| Claim: | 8. The method of claim 7 , wherein K is less than or equal to M. |
| Claim: | 9. The method of claim 7 , wherein multiplication of the unconstrained analog precoding matrix (F RF,UC) with any invertible matrix is substantially equal to the constrained analog precoding matrix (F RF). |
| Claim: | 10. The method of claim 7 , wherein the MIMO precoding matrix (F MU) is determined based on an effective channel matrix that comprises one or more of the constrained analog precoding matrix (F RF), the compensation matrix (F CM), and a raw channel matrix. |
| Claim: | 11. The method of claim 7 , wherein the constrained analog precoding circuitry comprises phase shifters, and wherein the analog multiplication of the unconstrained analog precoding matrix (F RF,UC) controls phases of the analog frequency-up-converted signals. |
| Claim: | 12. The method of claim 7 , wherein the constrained analog precoding circuitry comprises phase shifters, wherein multiplication of the constrained analog precoding matrix (F RF) and the compensation matrix (F CM) is substantially equal to the unconstrained analog precoding matrix (F RF,UC). |
| Claim: | 13. A system, comprising: one or more processors; and a non-transitory computer-readable storage device including one or more instructions for execution by the one or more processors and when executed operable to perform operations comprising: determining an unconstrained analog precoding matrix (F RF,UC), wherein the unconstrained analog precoding matrix (F RF,UC) is determined based on dominant eigenvectors of the sum of spatial channel covariance matrices of K users, and wherein K indicates a number of users communicating with a base station; determining a constrained analog precoding matrix (F RF) based on the unconstrained analog precoding matrix (F RF,UC); determining a compensation matrix (F CM), wherein the compensation matrix (F CM) is determined based on the constrained analog precoding (F RF); digitally multiplying K inputs with a multiple-input multiple-output (MIMO) precoding matrix (F MU) generating M outputs; digitally multiplying the M outputs with the compensation matrix (F CM) generating M compensation outputs; generating M analog frequency-up-converted signals based on the M compensation outputs; and analog multiplying the M analog frequency-up-converted signals with the analog precoding matrix (F RF) generating N output signals for transmission, wherein N is greater than M. |
| Claim: | 14. The system of claim 13 , wherein K is less than or equal to M. |
| Claim: | 15. The system of claim 13 , wherein multiplication of the unconstrained analog precoding matrix (F RF,UC) with any invertible matrix is substantially equal to the constrained analog precoding matrix (F RF). |
| Claim: | 16. The system of claim 13 , wherein the MIMO precoding matrix (F MU) is determined based on an effective channel matrix that comprises one or more of the constrained analog precoding matrix (F RF), the compensation matrix (F CM), and a raw channel matrix. |
| Claim: | 17. The system of claim 13 , wherein the constrained analog precoding circuitry comprises phase shifters, and wherein the analog multiplication of the unconstrained analog precoding matrix (F RF,UC) controls phases of the analog frequency-up-converted signals. |
| Patent References Cited: | 2010/0238984 September 2010 Sayana 2010/0260234 October 2010 Thomas 2011/0176439 July 2011 Mondal 2013/0034000 February 2013 Huo 2014/0146756 May 2014 Sahin 2015/0030092 January 2015 Krishnamurthy 2015/0326285 November 2015 Zirwas et al. 2016/0080051 March 2016 Sajadieh 2016/0119910 April 2016 Krzymien 2016/0269090 September 2016 Kim et al. 2016/0308597 October 2016 Kim et al. 2017/0302353 October 2017 Rahman |
| Other References: | X. Zhang, A. Molisch, and S. Kung, “Variable-phase-shift-based RF-baseband codesign for MIMO antenna selection,” IEEE Transactions on Signal Processing, vol. 53, No. 11, pp. 4091-4103, Nov. 2005. cited by applicant V. Venkateswaran and A. van der Veen, “Analog beamforming in MIMO communications with phase shift networks and online channel estimation,” IEEE Transactions on Signal Processing, vol. 58, No. 8, pp. 4131-4143, Aug. 2010. cited by applicant O. El Ayach, S. Rajagopal, S. Abu-Surra, Z. Pi, and R. Heath, “Spatially sparse precoding in millimeter wave MIMO systems,” IEEE Transactions on Wireless Communications, vol. 13, No. 3, pp. 1499-1513, Mar. 2014. cited by applicant W. Roh, J. Seol, J. Park, B. Lee, J. Lee, Y. Kim, J. Cho, K. Cheun, and F. Aryanfar, “Millimeter-wave beamforming as anenabling technology for 5G cellular communications: theoretical feasibility and prototype results,” IEEE Communications Magazine, vol. 52, No. 2, pp. 106-113, Feb. 2014. cited by applicant A. Alkhateeb, O. El Ayach, G. Leus, and R. Heath, “Hybrid precoding for millimeter wave cellular systems with partial channel knowledge,” in Proc. of Information Theory and Applications Workshop, Feb. 2013, pp. 1-5. cited by applicant X. Yu, J. Shen, J. Zhang, and K. Letaief, “Alternating minimization algorithms for hybrid precoding in millimeter wave MIMO systems,” IEEE Journal of Selected Topics in Signal Processing, vol. 10, No. 3, pp. 485-500, Apr. 2016. cited by applicant W. Ni and X. Dong, “Hybrid block diagonalization for massive multiuser MIMO systems,” IEEE Transactions on Communications, vol. 64, No. 1, pp. 201-211, Jan. 2016. cited by applicant L. Liang, W. Xu, and X. Dong, “Low-complexity hybrid precoding in massive multiuser MIMO systems,” IEEE Wireless Communications Letters, vol. 3, No. 6, pp. 653-656, Dec. 2014. cited by applicant F. Sohrabi and W. Yu, “Hybrid digital and analog beamforming design for large-scale antenna arrays,” IEEE Journal of Selected Topics in Signal Processing, vol. 10, No. 3, pp. 501-513, Apr. 2016. cited by applicant S. Han, C. I, C. Rowell, Z. Xu, S. Wang, and Z. Pan, “Large scale antenna system with hybrid digital and analog beamforming structure,” in Proc. of IEEE International Conference on Communications Workshops, Jun. 2014, pp. 842-847. cited by applicant A. Alkhateeb, G. Leus, and R. Heath, “Limited feedback hybrid precoding for multi-user millimeter wave systems,” IEEE Transactions on Wireless Communications, vol. 14, No. 11, pp. 6481-6494, Nov. 2015. cited by applicant R. Stirling-Gallacher and M. Rahman, “Multi-user MIMO strategies for a millimeter wave communication system using hybrid beam-forming,” in Proc. of IEEE International Conference on Communications, Jun. 2015, pp. 2437-2443. cited by applicant T. Bogale and L. Le, “Beamforming for multiuser massive MIMO systems: Digital versus hybrid analog-digital,” in Proc. of IEEE Global Communications Conference, Dec. 2014, pp. 4066-4071. cited by applicant E. Zhang and C. Huang, “On achieving optimal rate of digital precoder by RF-baseband codesign for MIMO systems,” in Proc. of IEEE Vehicular Technology Conference, Sep. 2014, pp. 1-5. cited by applicant A. Adhikary, J. Nam, J. Ahn, and G. Caire, “Joint spatial division and multiplexing: The large-scale array regime,” IEEE Transactions on Information Theory, vol. 59, No. 10, pp. 6441-6463, Oct. 2013. cited by applicant L. Liang, Y. Dai, W. Xu, and X. 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| Primary Examiner: | Varndell, Ross |
| Attorney, Agent or Firm: | Short, Brian R. |
| Dokumentencode: | edspgr.09967014 |
| Datenbank: | USPTO Patent Grants |
| Abstract: | Apparatuses, methods, and systems for beamforming in antenna systems are disclosed. A method includes determining an unconstrained analog precoding matrix (FRF,UC), wherein the unconstrained analog precoding matrix (FRF,UC) is determined based on M dominant eigenvectors of the sum of spatial channel covariance matrices of K users, and wherein K indicates a number of users communicating with a base station. The method further includes determining a constrained analog precoding matrix (FRF) based on the unconstrained analog precoding matrix (FRF,UC), determining a compensation matrix (FCM), digitally multiplying K inputs with a multiple-input multiple-output (MIMO) precoding matrix (FMU) generating M outputs, digitally multiplying the M outputs with the compensation matrix (FCM) generating M compensation outputs, generating M analog frequency-up-converted signals based on the M compensation outputs, and analog multiplying the M analog frequency-up-converted signals with the analog precoding matrix (FRF) generating N output signals for transmission, wherein N is greater than M. |
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