Patent ID: 7782969
Filing Date: 2010-08-24
Classification: H04B,H04J,H04L,H04W

Abstract:
1. An orthogonal frequency division multiplexing (OFDM) signal transmission apparatus for transmitting OFDM signals by using at least a first antenna and a second antenna, comprising: a subcarrier setting device configured to set some of subcarriers of the OFDM signals to pilot subcarriers for transmitting pilot signals, and remaining subcarriers thereof to data subcarriers for transmitting data signals, wherein the pilot signals to be transmitted include first pilot signals and second pilot signals, the first pilot signals to be transmitted by using a first pilot subcarrier of the pilot subcarriers have first polarities represented by first polarity data, the second pilot signals to be transmitted by using a second pilot subcarrier of the pilot subcarriers have second polarities represented by second polarity data, the first polarities being different from the second polarities, the first polarity data corresponds to a first polarity pattern of a plurality of polarity patterns, the second polarity data is different from the first polarity data, the first pilot signals are generated by using a product of a sequence and the first polarity data, and the second pilot signals are generated by using a product of the sequence and the second polarity data, and a transmitter for transmitting the first and second pilot signals to be transmitted using the first antenna and the second antenna in such a way that first ones of the first and second pilot signals which are transmitted by the first antenna and second ones of the first and second pilot signals which are transmitted by the second antenna have different polarities, wherein a first wireless packet based on a first communication scheme is transmitted by using at least the first antenna, and a second wireless packet based on a second communication scheme is transmitted by using at least the first antenna and the second antenna.