Scattered pilot pattern and channel estimation method for MIMO-OFDM systems
DCFirst Claim
1. A method of transmitting symbols using Orthogonal Frequency Division Multiplexing, OFDM, frames at an OFDM transmitter having at least two transmitting antennas, the OFDM frames having a time domain and a frequency domain, each OFDM frame 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:
- transmitting, on an OFDM symbol, pilot symbols corresponding to the first antenna using a scattered pattern; and
transmitting, on the OFDM symbol, pilot symbols corresponding to the second antenna using the scattered pattern, wherein the pilot symbols for the first antenna correspond to a first code and the pilot symbols for the second antenna correspond to a second code.
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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
42 Claims
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1. A method of transmitting symbols using Orthogonal Frequency Division Multiplexing, OFDM, frames at an OFDM transmitter having at least two transmitting antennas, the OFDM frames having a time domain and a frequency domain, each OFDM frame 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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transmitting, on an OFDM symbol, pilot symbols corresponding to the first antenna using a scattered pattern; and transmitting, on the OFDM symbol, pilot symbols corresponding to the second antenna using the scattered pattern, wherein the pilot symbols for the first antenna correspond to a first code and the pilot symbols for the second antenna correspond to a second code. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A device for transmitting pilot symbols using Orthogonal Frequency Division Multiplexing, OFDM, frames at an OFDM transmitter having at least two transmitting antennas, the OFDM frames having a time domain and a frequency domain, each OFDM frame comprising a plurality of OFDM symbols in the time domain, and a plurality of sub-carriers in the frequency domain, comprising:
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a first antenna of the OFDM transmitter; a second antenna of the OFDM transmitter; and one or more processors configured to; cause transmission via the first antenna, on an OFDM symbol, pilot symbols corresponding to the first antenna using a scattered pattern; and cause transmission via the second antenna, on the OFDM symbol, pilot symbols corresponding to the second antenna using the scattered pattern, wherein the pilot symbols for the first antenna correspond to a first code and the pilot symbols for the second antenna correspond to a second code. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A non-transitory computer readable medium for transmitting symbols using Orthogonal Frequency Division Multiplexing, OFDM, frames at an OFDM transmitter having at least two transmitting antennas, the OFDM frames having a time domain and a frequency domain, each OFDM frame comprising a plurality of OFDM symbols in the time domain and a plurality of sub-carriers in the frequency domain, the computer readable medium storing instructions to cause a processor to perform operations comprising:
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transmitting, on an OFDM symbol, pilot symbols corresponding to the first antenna using a scattered pattern; and transmitting, on the OFDM symbol, pilot symbols corresponding to the second antenna using the scattered pattern, wherein the pilot symbols for the first antenna correspond to a first code and the pilot symbols for the second antenna correspond to a second code. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24)
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25. A method for receiving symbols using Orthogonal Frequency Division Multiplexing, OFDM, frames transmitted from an OFDM transmitter having at least two transmitting antennas, the OFDM frames having a time domain and a frequency domain, each OFDM frame 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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receiving, on an OFDM symbol, pilot symbols corresponding to the first antenna using a scattered pattern; and receiving, on the OFDM symbol, pilot symbols corresponding to the second antenna using the scattered pattern, wherein the pilot symbols for the first antenna correspond to a first code and the pilot symbols for the second antenna correspond to a second code. - View Dependent Claims (26, 27, 28, 29, 30)
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31. A User Equipment (UE) for receiving pilot symbols using Orthogonal Frequency Division Multiplexing, OFDM, frames transmitted from an OFDM transmitter having at least two transmitting antennas, the OFDM frames having a time domain and a frequency domain, each OFDM frame comprising a plurality of OFDM symbols in the time domain and a plurality of sub-carriers in the frequency domain, comprising:
a receiver configured to; receive, on an OFDM symbol, pilot symbols corresponding to the first antenna using a scattered pattern; and receive, on the OFDM symbol, pilot symbols corresponding to the second antenna using the scattered pattern, wherein the pilot symbols for the first antenna correspond to a first code and the pilot symbols for the second antenna correspond to a second code. - View Dependent Claims (32, 33, 34, 35, 36)
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37. A non-transitory computer readable medium for receiving symbols using Orthogonal Frequency Division Multiplexing, OFDM, frames transmitted from an OFDM transmitter having at least two transmitting antennas, the OFDM frames having a time domain and a frequency domain, each OFDM frame comprising a plurality of OFDM symbols in the time domain and a plurality of sub-carriers in the frequency domain, the computer readable medium storing instructions to cause a processor to perform operations comprising:
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receiving, on an OFDM symbol, pilot symbols corresponding to the first antenna using a scattered pattern; and receiving, on the OFDM symbol, pilot symbols corresponding to the second antenna using the scattered pattern, wherein the pilot symbols for the first antenna correspond to a first code and the pilot symbols for the second antenna correspond to a second code. - View Dependent Claims (38, 39, 40, 41, 42)
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Specification