Scattered pilot pattern and channel estimation method for MIMO-OFDM systems
First Claim
1. A method of inserting pilot symbols into Orthogonal Frequency Division Multiplexing (OFDM) frames at an OFDM base station having at least one transmitting antenna, the OFDM base station having an adjacent OFDM base station having at least one transmitting antenna, 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:
- for each transmitting antenna of the OFDM base station, inserting scattered pilot symbols in a scattered pattern in time-frequency, wherein the scattered pattern is offset from a scattered pattern of the adjacent OFDM base station.
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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.
82 Citations
37 Claims
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1. A method of inserting pilot symbols into Orthogonal Frequency Division Multiplexing (OFDM) frames at an OFDM base station having at least one transmitting antenna, the OFDM base station having an adjacent OFDM base station having at least one transmitting antenna, 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:
for each transmitting antenna of the OFDM base station, inserting scattered pilot symbols in a scattered pattern in time-frequency, wherein the scattered pattern is offset from a scattered pattern of the adjacent OFDM base station. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A system comprising:
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an Orthogonal Frequency Division Multiplexing (OFDM) base station having at least one transmit antenna; and an adjacent OFDM base station having at least one transmit antenna;
the OFDM base station being adapted to insert pilot symbols into 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, by, for each antenna, inserting pilot symbols in a scattered pattern in time-frequency, wherein the scattered pattern is offset from a scattered pattern of the adjacent OFDM base station. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A method of receiving pilot symbols in Orthogonal Frequency Division Multiplexing (OFDM) frames at an OFDM receiver having at least one receiving antenna from an OFDM base station having at least one transmitting antenna, the OFDM base station having an adjacent OFDM base station having at least one transmitting antenna, 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:
receiving scattered pilot symbols in a scattered pattern in time-frequency for each transmitting antenna, wherein the scattered patterns is offset from a scattered pattern of the adjacent OFDM base station. - View Dependent Claims (23, 24, 25, 26, 27, 28, 37)
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29. An OFDM receiver configured to receive pilot symbols in OFDM frames, comprising:
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at least one receiving antenna configured to receive communications from an OFDM base station having at least one transmitting antenna, the OFDM base station having an adjacent OFDM base station having at least one transmitting antenna, 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; and one or more processors configured to receive scattered pilot symbols in a scattered pattern in time-frequency for each transmitting antenna, wherein the scattered patterns is offset from a scattered pattern of the adjacent OFDM base station. - View Dependent Claims (30, 31, 32, 33, 34, 35, 36)
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Specification