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US 8,942,303 B1Granted
Pilot assisted channel estimation
AssigneeSiTune Corporation
InventorsMarzieh Veyseh, Mahdi Khoshgard
Life of this patent
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Abstract
Systems and methods are described for the implementation of a receiver that includes a channel estimation block that uses known pilots to estimate the value of channel gain and phase at data subcarrier indexes. Time interpolation as well as an auto regression filter can be to estimate the channel gain and phase at the “missing” pilot indexes as well as frequency interpolation to estimate the value of the channel at data subcarrier indexes.
Claims20
A method, comprising:
- receiving an Orthogonal Frequency Division Multiplexing (OFDM) transmission that includes a plurality of OFDM symbols, each one of the plurality of OFDM symbols including data subcarriers and pilot subcarriers;
- determining a channel value at pilot subcarrier indexes for a current OFDM symbol of the plurality of OFDM symbols;
- updating, based at least in part on the channel value at the pilot subcarrier indexes of the current OFDM symbol, the channel value of pilot subcarriers indexes for a first grouping of OFDM symbols of the plurality of OFDM symbols and a second grouping of OFDM symbols of the plurality of OFDM symbols;
- determining a channel value at pilot subcarrier indexes for a reference OFDM symbol by computing a weighted average of the channel value of the pilot subcarrier indexes for the first grouping of OFDM symbols and the channel value of the pilot subcarrier indexes for the second grouping of OFDM symbols;
- time filtering the channel value for the pilot subcarrier indexes of the reference symbol;
- estimating, using at least one frequency interpolation function, the channel value at data subcarrier indexes for the reference symbol based at least in part on the channel value for the pilot subcarrier indexes of the reference symbol;
- and
- dividing at least a portion of the data subcarriers in the reference OFDM symbol by the channel value of the data subcarrier indexes to equalize the OFDM transmission and reduce a portion of channel distortion.
5 more elements
A receiver, comprising:
- a channel estimation component;
- at least one computing device processor;
- a memory device including instructions that, when executed by the at least one computing device processor, enable the receiver to:
- receive an Orthogonal Frequency Division Multiplexing (OFDM) transmission that includes a plurality of OFDM symbols, each one of the plurality of OFDM symbols including data subcarriers and pilot subcarriers, wherein the channel estimation component is configured to:
- determine a channel value at pilot subcarrier indexes for a current OFDM symbol of the plurality of OFDM symbols;
- update, based at least in part on the channel value at the pilot subcarrier indexes of the current OFDM symbol, the channel value of pilot subcarriers indexes for a first grouping of OFDM symbols of the plurality of OFDM symbols and a second grouping of OFDM symbols of the plurality of OFDM symbols;
- determine a channel value at pilot subcarrier indexes for a reference OFDM symbol by computing a weighted average of the channel value of the pilot subcarrier indexes for the first grouping of OFDM symbols and the channel value of the pilot subcarrier indexes for the second grouping of OFDM symbols;
- time filter the channel value for the pilot subcarrier indexes of the reference symbol;
- estimate, using at least one frequency interpolation function, the channel value at data subcarrier indexes for the reference symbol based at least in part on the channel value for the pilot subcarrier indexes of the reference symbol;
- and
- divide at least a portion of the data subcarriers in the reference OFDM symbol by the channel value of the data subcarrier indexes to equalize the OFDM transmission and reduce a portion of channel distortion.
8 more elements
A non-transitory computer readable storage medium storing one or more sequences of instructions executable by one or more processors to perform a set of operations comprising:
- receiving an Orthogonal Frequency Division Multiplexing (OFDM) transmission that includes a plurality of OFDM symbols, each one of the plurality of OFDM symbols including data subcarriers and pilot subcarriers;
- determining a channel value at pilot subcarrier indexes for a current OFDM symbol of the plurality of OFDM symbols;
- updating, based at least in part on the channel value at the pilot subcarrier indexes of the current OFDM symbol, the channel value of pilot subcarriers indexes for a first grouping of OFDM symbols of the plurality of OFDM symbols and a second grouping of OFDM symbols of the plurality of OFDM symbols;
- determining a channel value at pilot subcarrier indexes for a reference OFDM symbol by computing a weighted average of the channel value of the pilot subcarrier indexes for the first grouping of OFDM symbols and the channel value of the pilot subcarrier indexes for the second grouping of OFDM symbols;
- time filtering the channel value for the pilot subcarrier indexes of the reference symbol;
- estimating, using at least one frequency interpolation function, the channel value at data subcarrier indexes for the reference symbol based at least in part on the channel value for the pilot subcarrier indexes of the reference symbol;
- and
- dividing at least a portion of the data subcarriers in the reference OFDM symbol by the channel value of the data subcarrier indexes to equalize the OFDM transmission and reduce a portion of channel distortion.
5 more elements
Dependencies are inferred from the claim text.