Adaptive two-dimensional channel interpolation

摘要

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).

主权项

1. A method of inserting pilot symbols into OFDM sub-frames for transmission by a plurality of transmitting antenna, the OFDM sub-frames having a time domain and a frequency domain, each OFDM sub-frame comprising a plurality of OFDM symbols, the method comprising:
for each sub-frame, defining a set of at least two OFDM symbols that are to contain pilot symbols for the sub-frame, wherein none of the OFDM symbols of the set are consecutive in time; and at each antenna of said plurality of transmitting antennas, inserting pilot symbols in each OFDM symbol of the set in a scattered pattern that does not interfere with the scattered pattern inserted at any other antenna of said plurality of transmitting antennas; wherein the scattered patterns of the respective antennas are identical but staggered in the frequency domain; wherein the scattered pattern for each antenna is not frequency-adjacent to the scattered pattern for any other antenna.