Scattered Pilot Pattern And Channel Estimation Method For MIMO-OFDM Systems
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0 Petitions
Accused Products
Abstract
A method and apparatus are provided for reducing the number of pilot symbols within a MIMO-OFDM communication system, and for improving channel estimation within such a system. For each transmitting antenna in an OFDM transmitter, pilot symbols are encoded so as to be unique to the transmitting antenna. The encoded pilot symbols are then inserted into an OFDM frame to form a diamond lattice, the diamond lattices for the different transmitting antennae using the same frequencies but being offset from each other by a single symbol in the time domain. At the OFDM receiver, a channel response is estimated for a symbol central to each diamond of the diamond lattice using a two-dimensional interpolation. The estimated channel responses are smoothed in the frequency domain. The channel responses of remaining symbols are then estimated by interpolation in the frequency domain.
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Citations
30 Claims
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1-12. -12. (canceled)
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13. A method of transmitting symbols using Orthogonal Frequency Division Multiplexing (OFDM) frames at an OFDM base station using a plurality of processing paths of an OFDM transmitter to transmit OFDM signals, the OFDM frames having a time domain and a frequency domain, each of the OFDM frames comprising a plurality of OFDM symbols in the time domain and a plurality of sub-carriers in the frequency domain, the method comprising the steps of:
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for a first processing path of the OFDM transmitter, transmitting scattered pilot symbols in a scattered pattern in time-frequency by transmitting a first set of pilot symbols in a first pattern in time-frequency and transmitting a second set of pilot symbols in a second pattern in time-frequency at same frequencies as the first pattern, offset by one OFDM symbol in the time domain; and for a second processing path of the OFDM transmitter, transmitting scattered pilot symbols using the scattered pattern. - View Dependent Claims (14, 15, 16, 17, 18)
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19. A base station comprising:
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an Orthogonal Frequency Division Multiplexing (OFDM) transmitter including a first processing path and a second processing path, wherein the OFDM transmitter is configured to transmit symbols using OFDM frames, the OFDM frames have a time domain and a frequency domain, and each of the OFDM frames comprises a plurality of OFDM symbols in the time domain and a plurality of sub-carriers in the frequency domain; at least one hardware processor; and a non-transitory computer-readable storage medium coupled to the at least one hardware processor and storing programming instructions for execution by the at least one hardware processor, wherein the programming instructions, when executed, cause the base station to perform operations comprising; for the first processing path of the OFDM transmitter, transmitting scattered pilot symbols in a scattered pattern in time-frequency by transmitting a first set of pilot symbols in a first pattern in time-frequency and transmitting a second set of pilot symbols in a second pattern in time-frequency at same frequencies as the first pattern, offset by one OFDM symbol in the time domain; and for the second processing path of the OFDM transmitter, transmitting scattered pilot symbols using the scattered pattern. - View Dependent Claims (20, 21, 22, 23, 24)
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25. A non-transitory computer-readable medium storing instructions that are operable when executed by data processing apparatus to perform operations of transmitting symbols using Orthogonal Frequency Division Multiplexing (OFDM) frames at an OFDM base station using a plurality of processing paths of an OFDM transmitter to transmit OFDM signals, the OFDM frames having a time domain and a frequency domain, each of the OFDM frames comprising a plurality of OFDM symbols in the time domain and a plurality of sub-carriers in the frequency domain, the operations comprising:
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for a first processing path of the OFDM transmitter, transmitting scattered pilot symbols in a scattered pattern in time-frequency by transmitting a first set of pilot symbols in a first pattern in time-frequency and transmitting a second set of pilot symbols in a second pattern in time-frequency at same frequencies as the first pattern, offset by one OFDM symbol in the time domain; and for a second processing path of the OFDM transmitter, transmitting scattered pilot symbols using the scattered pattern. - View Dependent Claims (26, 27, 28, 29, 30)
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Specification