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A method and apparatus for improving channel estimation within an OFDM communication system. Channel estimation in OFDM is usually performed with the aid of pilot symbols. The pilot symbols are typically spaced in time and frequency. The set of frequencies and times at which pilot symbols are insert

A method and apparatus for improving channel estimation within an OFDM communication system. Channel estimation in OFDM is usually performed with the aid of pilot symbols. The pilot symbols are typically spaced in time and frequency. The set of frequencies and times at which pilot symbols are inserted is referred to as a pilot pattern. In some cases, the pilot pattern is a diagonal-shaped lattice, either regular or irregular. The method first interpolates in the direction of larger coherence (time or frequency). Using these measurements, the density of pilot symbols in the direction of faster change will be increased thereby improving channel estimation without increasing overhead. As such, the results of the first interpolating step can then be used to assist the interpolation in the dimension of smaller coherence (time or frequency).

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1. An orthogonal frequency division multiplexing (OFDM) transmitter adapted to insert pilot symbols into OFDM frames, the OFDM frames having a time domain and a frequency domain, each OFDM frame comprising a plurality of OFDM symbols, comprising: a plurality of antennas; andprocessing hardware coupl

1. An orthogonal frequency division multiplexing (OFDM) transmitter adapted to insert pilot symbols into OFDM frames, the OFDM frames having a time domain and a frequency domain, each OFDM frame comprising a plurality of OFDM symbols, comprising: a plurality of antennas; andprocessing hardware coupled to the plurality of antennas, wherein the processing hardware is configured to, for at least a first frame: insert pilot symbols within a first set of data for transmission by a first antenna of the plurality of antennas, wherein the pilot symbols are designated for transmission using a first set of at least two OFDM symbols, wherein the at least two OFDM symbols of the first set are non-consecutive in both the time domain and the frequency domain;insert pilot symbols within a second set of data for transmission by a first antenna of the plurality of antennas, wherein the pilot symbols are designated for transmission using a second set of at least two OFDM symbols, wherein the at least two OFDM symbols of the second set are non-consecutive in both the time domain and the frequency domain;insert pilot symbols within a third set of data for transmission by a first antenna of the plurality of antennas, wherein the pilot symbols are designated for transmission using a third set of at least two OFDM symbols, wherein the at least two OFDM symbols of the third set are non-consecutive in both the time domain and the frequency domain;insert pilot symbols within a fourth set of data for transmission by a fourth antenna of the plurality of antennas, wherein the pilot symbols are designated for transmission using a fourth set of at least two OFDM symbols, wherein the at least two OFDM symbols of the fourth set are non-consecutive in both the time domain and the frequency domain;wherein no two of the OFDM symbols of the first, second, third, and fourth sets of at least two OFDM symbols occupy the same position in both the time domain and the frequency domain, and wherein the OFDM symbols in the first, second, third, and fourth sets of at least two OFDM symbols include at least two OFDM symbols that have consecutive positions in either the time domain or the frequency domain;transmit the first set of data, including the pilot symbols inserted within the first set of data, using the first antenna;transmit the second set of data, including the pilot symbols inserted within the second set of data, using the second antenna;transmit the third set of data, including the pilot symbols inserted within the third set of data, using the third antenna; andtransmit the fourth set of data, including the pilot symbols inserted within the fourth set of data, using the fourth antenna. 2. The OFDM transmitter of claim 1, wherein the first set of at least two OFDM symbols and the second set of at least two OFDM symbols are not consecutive in either the time domain or the frequency domain. 3. The OFDM transmitter of claim 2, wherein one or more OFDM symbols of the third set of at least two OFDM symbols are consecutive to one or more OFDM symbols of the first set of at least OFDM symbols in either the time domain or the frequency domain and wherein one or more OFDM symbols of the fourth set of at least two OFDM symbols are consecutive to one or more OFDM symbols of the second set of at least OFDM symbols in either the time domain or the frequency domain. 4. The OFDM transmitter of claim 1, wherein the at least two OFDM symbols included in the first, second, third, and fourth sets of at least two OFDM symbols have consecutive positions in the time domain. 5. The OFDM transmitter of claim 1, wherein inserting the pilot symbols in the first, second, third, and fourth sets of data, and said transmitting the first, second, third, and fourth sets of data are for at least a first subframe of the at least a first frame. 6. The OFDM transmitter of claim 1, wherein the first set of at least two OFDM symbols and the second set of at least two OFDM symbols have a same pattern but are staggered in the frequency domain. 7. The OFDM transmitter of claim 1, wherein at least one of the first, second, third, and fourth sets of at least two OFDM symbols form regular diamond lattices. 8. The OFDM transmitter of claim 1, wherein at least one of the first, second, third, and fourth sets of at least two OFDM symbols form irregular diamond lattices. 9. The OFDM transmitter of claim 1, wherein at least one of the first, second, third, and fourth sets of at least two OFDM symbols are kite shaped. 10. A method of inserting pilot symbols in orthogonal frequency division multiplexing (OFDM) frames for transmission by a plurality of antennas, the OFDM frames having a time domain and a frequency domain, each OFDM frame comprising a plurality of OFDM symbols, the method comprising, for at least a first frame: transmitting, using a first antenna of the plurality of antennas, pilot symbols in a first set of at least two OFDM symbols, wherein the at least two OFDM symbols of the first set are non-consecutive in both the time domain and the frequency domain;transmitting, using a second antenna of the plurality of antennas, pilot symbols in a second set of OFDM symbols, wherein the at least two OFDM symbols of the second set are non-consecutive in both the time domain and the frequency domain;transmitting, using a third antenna of the plurality of antennas, pilot symbols in a third set of OFDM symbols, wherein the at least two OFDM symbols of the third set are non-consecutive in both the time domain and the frequency domain;transmitting, using a fourth antenna of the plurality of antennas, pilot symbols in a fourth set of OFDM symbols, wherein the at least two OFDM symbols of the fourth set are non-consecutive in both the time domain and the frequency domain; andwherein no two of the OFDM symbols of the first, second, third, and fourth sets of at least two OFDM symbols occupy the same position in both the time domain and the frequency domain, and wherein the OFDM symbols in the first, second, third, and fourth sets of at least two OFDM symbols include at least two OFDM symbols that have consecutive positions in either the time domain or the frequency domain. 11. The method of claim 10, wherein the first set of at least two OFDM symbols and the second set of at least two OFDM symbols are not consecutive in either the time domain or the frequency domain. 12. The method of claim 11, wherein one or more OFDM symbols of the third set of at least two OFDM symbols are consecutive to one or more OFDM symbols of the first set of at least OFDM symbols in either the time domain or the frequency domain and wherein one or more OFDM symbols of the fourth set of at least two OFDM symbols are consecutive to one or more OFDM symbols of the second set of at least OFDM symbols in either the time domain or the frequency domain. 13. The method of claim 10, wherein the at least two OFDM symbols included in the first, second, third, and fourth sets of at least two OFDM symbols have consecutive positions in the time domain. 14. The method of claim 10, wherein said transmitting the first, second, third, and fourth sets of data are for at least a first sub-frame of the at least a first frame. 15. The method of claim 10, wherein the first set of at least two OFDM symbols and the second set of at least two OFDM symbols have a same pattern but are staggered in the frequency domain. 16. A non-transitory, computer accessible memory medium storing program instructions for inserting pilot symbols into orthogonal frequency division multiplexing (OFDM) frames for transmission by a plurality of antennas, the OFDM frames having a time domain and a frequency domain, each OFDM sub-frame comprising a plurality of OFDM symbols, wherein the program instructions are executable by one or more processors to, for at least a first frame: transmit, using a first antenna of the plurality of antennas, pilot symbols in a first set of at least two OFDM symbols, wherein the at least two OFDM symbols of the first set are non-consecutive in both the time domain and the frequency domain;transmit, using a second antenna of the plurality of antennas, pilot symbols in a second set of OFDM symbols, wherein the at least two OFDM symbols of the second set are non-consecutive in both the time domain and the frequency domain;transmit, using a third antenna of the plurality of antennas, pilot symbols in a third set of OFDM symbols, wherein the at least two OFDM symbols of the third set are non-consecutive in both the time domain and the frequency domain;transmit, using a fourth antenna of the plurality of antennas, pilot symbols in a fourth set of OFDM symbols, wherein the at least two OFDM symbols of the fourth set are non-consecutive in both the time domain and the frequency domain; andwherein no two of the OFDM symbols of the first, second, third, and fourth sets of at least two OFDM symbols occupy the same position in both the time domain and the frequency domain, and wherein the OFDM symbols in the first, second, third, and fourth sets of at least two OFDM symbols include at least two OFDM symbols that have consecutive positions in either the time domain or the frequency domain. 17. The non-transitory, computer accessible memory medium of claim 16, wherein the first set of at least two OFDM symbols and the second set of at least two OFDM symbols are not consecutive in either the time domain or the frequency domain. 18. The non-transitory, computer accessible memory medium of claim 16, wherein one or more OFDM symbols of the third set of at least two OFDM symbols are consecutive to one or more OFDM symbols of the first set of at least OFDM symbols in either the time domain or the frequency domain and wherein one or more OFDM symbols of the fourth set of at least two OFDM symbols are consecutive to one or more OFDM symbols of the second set of at least OFDM symbols in either the time domain or the frequency domain. 19. The non-transitory, computer accessible memory medium of claim 16, wherein the at least two OFDM symbols included in the first, second, third, and fourth sets of at least two OFDM symbols have consecutive positions in the time domain. 20. The non-transitory, computer accessible memory medium of claim 16, wherein said transmitting the first, second, third, and fourth sets of data are for at least a first sub-frame of the at least a first frame.