Scattered pilot pattern and channel estimation method for MIMO-OFDM systems
DCFirst Claim
1. 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 two transmitting antennas, the OFDM base station having an adjacent OFDM base station 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 subcarriers in the frequency domain, the method comprising:
- receiving scattered pilot symbols in a scattered pattern in time-frequency from each transmitting antenna of the OFDM base station, wherein the scattered pattern is offset from a scattered pattern of the adjacent OFDM base station.
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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.
54 Citations
20 Claims
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1. 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 two transmitting antennas, the OFDM base station having an adjacent OFDM base station 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 subcarriers in the frequency domain, the method comprising:
receiving scattered pilot symbols in a scattered pattern in time-frequency from each transmitting antenna of the OFDM base station, 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 user equipment (UE) of a wireless network, the wireless network including a first Orthogonal Frequency Division Multiplexing (OFDM) base station having at least two transmitting antennas, the OFDM base station adjacent to a second OFDM base station having at least two transmitting antennas, the UE comprising:
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a receiving antenna; and a receiver configured to; receive scattered pilot symbols in a scattered pattern in time-frequency for each transmitting antenna of the first OFDM base station, wherein the scattered pattern from the first OFDM base station is offset from a scattered pattern of the second OFDM base station; and receive the scattered pilot symbols in OFDM frames from the first OFDM base station, the OFDM frames having a time domain and a frequency domain, each OFDM frame having a plurality of OFDM symbols in the time domain and a plurality of subcarriers in the frequency domain. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification