Synchronization in a beamforming system
First Claim
1. A method comprising:
- allocating time-frequency resource blocks by a base station in a beamforming OFDM network for control beam (CB) transmission, wherein each allocated time-frequency resource block comprises a plurality of OFDM symbols in time domain and a plurality of subcarriers in frequency domain;
partitioning each resource block of the allocated time-frequency resource blocks into a pilot part and a data part by the base station, wherein the pilot part comprises M pilot structures and each pilot structure of the M pilot structures comprises a number of the plurality of OFDM symbols in time domain and a number of the plurality of subcarriers in frequency domain; and
inserting pilot symbols of a pilot signal in each of the number of the plurality of OFDM symbols in the pilot part by the base station by modulating each of the M pilot structures with a signature sequence, wherein the pilot symbols are repeated for L times in each of the M pilot structures, wherein each of the M pilot structures is applied by multiple variable-length Inverse Fast Fourier Transfers (IFFTs) having varying IFFT window sizes with corresponding multiple varying cyclic prefix (CP) lengths for CB transmission, wherein both the pilot symbols and data symbols are multiplexed in subcarriers of each of the number of the plurality of OFDM symbols that employs the multiple variable-length IFFTs, and wherein M and L are positive integers.
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Abstract
A beamforming system synchronization architecture is proposed to allow a receiving device to synchronize to a transmitting device in time, frequency, and spatial domain in the most challenging situation with very high pathloss. A periodically configured time-frequency resource blocks in which the transmitting device uses the same beamforming weights for its control beam transmission to the receiving device. A pilot signal for each of the control beams is transmitted in each of the periodically configured time-frequency resource blocks. Pilot symbols are inserted into pilot structures and repeated for L times in each pilot structure. The L repetitions can be implemented by one or more Inverse Fast Fourier Transfers (IFFTs) with corresponding one or more cyclic prefix (CP) lengths.
75 Citations
22 Claims
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1. A method comprising:
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allocating time-frequency resource blocks by a base station in a beamforming OFDM network for control beam (CB) transmission, wherein each allocated time-frequency resource block comprises a plurality of OFDM symbols in time domain and a plurality of subcarriers in frequency domain; partitioning each resource block of the allocated time-frequency resource blocks into a pilot part and a data part by the base station, wherein the pilot part comprises M pilot structures and each pilot structure of the M pilot structures comprises a number of the plurality of OFDM symbols in time domain and a number of the plurality of subcarriers in frequency domain; and inserting pilot symbols of a pilot signal in each of the number of the plurality of OFDM symbols in the pilot part by the base station by modulating each of the M pilot structures with a signature sequence, wherein the pilot symbols are repeated for L times in each of the M pilot structures, wherein each of the M pilot structures is applied by multiple variable-length Inverse Fast Fourier Transfers (IFFTs) having varying IFFT window sizes with corresponding multiple varying cyclic prefix (CP) lengths for CB transmission, wherein both the pilot symbols and data symbols are multiplexed in subcarriers of each of the number of the plurality of OFDM symbols that employs the multiple variable-length IFFTs, and wherein M and L are positive integers. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method comprising:
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receiving control beam transmission by a user equipment (UE) from a base station in a beamforming OFDM network, wherein the UE receives a time domain signal from pilot symbols transmitted over periodically allocated time-frequency resource blocks of the received control beam, wherein each allocated time-frequency resource block comprises a plurality of OFDM symbols in time domain and a plurality of subcarriers in frequency domain; processing the received time domain signal by the UE by removing multiple cyclic prefixes (CPs) with a variable CP length and performing corresponding multiple variable-length Fast Fourier Transfers (FFTs) to reconstruct a pilot part of a resource block, wherein the pilot part comprises M pilot structures and each of the M pilot structures comprises a number of the plurality of OFDM symbols in time domain and a number of the plurality of subcarriers in frequency domain, and wherein a data part of the same resource block is also reconstructed by the multiple variable-length FFTs; and extracting the pilot symbols from each of the M pilot structures by the UE by demodulating each of the M pilot structures to a signature sequence, wherein the pilot symbols are repeated for L times in each of the M pilot structures, and wherein M and L are positive integers. - View Dependent Claims (12, 13, 14, 15, 16)
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17. A user equipment (UE), comprising:
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a radio frequency (RF) receiver that receives control beam transmission by a user equipment (UE) from a base station in a beamforming OFDM network, wherein the UE receives a time domain signal from pilot symbols transmitted over periodically allocated time-frequency resource blocks of the received control beam, wherein each allocated time-frequency resource block comprises a plurality of OFDM symbols in time domain and a plurality of subcarriers in frequency domain; a processor that processes the received time domain signal by removing multiple cyclic prefixes (CPs) with a variable CP length and performing corresponding multiple variable-length Fast Fourier Transfers (FFTs) to reconstruct a pilot part of a resource block, wherein the pilot part comprises M pilot structures and each pilot structure of the M pilot structures comprises a number of the plurality of OFDM symbols in time domain and a number of the plurality of subcarriers in frequency domain, and wherein a data part of the same resource block is also reconstructed by the multiple variable-length FFTs; and a symbol extractor that extracts the pilot symbols from each of the M pilot structures by demodulating each of the M pilot structures to a signature sequence, wherein the pilot symbols are repeated for L times in each of the M pilot structures, and wherein M and L are positive integers. - View Dependent Claims (18, 19, 20, 21, 22)
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Specification