Scattered pilot pattern and channel estimation method for MIMO-OFDM systems
First Claim
1. A method of transmitting symbols using Orthogonal Frequency Division Multiplexing (OFDM) frames at an OFDM base station using a first plurality of processing paths to transmit OFDM signals, the OFDM base station neighboring an adjacent OFDM base station using a second plurality of processing paths to transmit OFDM signals, the OFDM frames having a time domain and a frequency domain, each of the OFDM frames 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:
- for each processing path, transmitting scattered pilot symbols using a respective scattered pattern in time-frequency, wherein the respective scattered pattern is offset from a scatted 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.
98 Citations
34 Claims
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1. A method of transmitting symbols using Orthogonal Frequency Division Multiplexing (OFDM) frames at an OFDM base station using a first plurality of processing paths to transmit OFDM signals, the OFDM base station neighboring an adjacent OFDM base station using a second plurality of processing paths to transmit OFDM signals, the OFDM frames having a time domain and a frequency domain, each of the OFDM frames 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:
for each processing path, transmitting scattered pilot symbols using a respective scattered pattern in time-frequency, wherein the respective scattered pattern is offset from a scatted pattern of the adjacent OFDM base station. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A base station comprising:
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a memory; at least two processing paths; and at least one processor communicatively coupled with the memory and configured to; cause transmission of Orthogonal Frequency Division Multiplexing (OFDM) signals in OFDM frames using the at least two processing paths, wherein the OFDM frames have a time domain and a frequency domain, and each of the OFDM frames comprises a plurality of OFDM symbols in the time domain and a plurality of sub-carriers in the frequency domain; and for each of the at least two processing paths, cause transmission of scattered pilot symbols using a respective scattered pattern in time-frequency, wherein the respective scattered pattern is offset from a scatted pattern of an adjacent OFDM base station, wherein the adjacent OFDM base station uses a second plurality of processing paths to transmit OFDM signals. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A non-transitory computer-readable medium storing instructions that are operable when executed by data processing apparatus to perform operations comprising:
- transmitting Orthogonal Frequency Division Multiplexing (OFDM) signals in OFDM frames at an OFDM base station using a first plurality of processing paths, wherein the OFDM frames have a time domain and a frequency domain, and each of the OFDM frames comprises a for each processing path, transmitting scattered pilot symbols using a respective scattered pattern in time-frequency, wherein the respective scattered pattern is offset from a scattered pattern of an adjacent OFDM base station, wherein the adjacent OFDM base station uses a second plurality of processing paths to transmit OFDM signals.
- View Dependent Claims (24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
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34. A telecommunication system, comprising:
- a first Orthogonal Frequency Division Multiplexing (OFDM) base station comprising;
a first memory;
a first plurality of processing paths; and
at least a first processor communicatively coupled with the first memory and configured to cause transmission of OFDM signals using the first plurality of processing paths, a second Orthogonal Frequency Division Multiplexing (OFDM) base station, adjacent to the first OFDM base station comprising;
a second plurality of processing paths; and
at least a second processor communicatively coupled with the second memory and configured to;
cause transmission of OFDM signals in OFDM frames using the second plurality of processing paths, wherein the OFDM frames have a time domain and a frequency domain, and each of the OFDM frames comprises a plurality of OFDM symbols in the time domain and a plurality of sub-carriers in the frequency domain; and
for each of the first plurality of processing paths, cause transmission of scattered pilot symbols using a respective scattered pattern in time-frequency, wherein the respective scattered pattern is offset from a scattered pattern of the first OFDM base station.
- a first Orthogonal Frequency Division Multiplexing (OFDM) base station comprising;
Specification