The Doshisha

Advanced Telecommunications Research Institute International

Hideichi Sasaoka

Yusuke Miyamoto

Takashi Ohira

Hisato Iwai

Tomoyuki Aono

A MC-CDMA transmitter and an MC-CDMA receiver are provided, which use a novel orthogonal spreading code that allows an effect by a delay wave to appear in only a specific user. An MC-CDMA system includes: a transmitter which multiplies a transmitting signal by a sinusoidal signal which has an amplitude of r and is orthogonal as a result that the frequency periods are different among users, in a frequency domain to be spread and split into orthogonal sub-carriers, and multiplexes the sub-carriers; and a receiver for receiving a transmitting signal from the transmitter in a manner that a sinusoidal signal, which has an amplitude of r and is orthogonal as a result that the frequency periods are different among users, is multiplied by the transmitting signal in a frequency domain, and the resultant is inversely spread.

MC-CDMA system, transmitter and receiver

A radio communications system includes radio devices, and antenna and an array antenna. The radio devices communicate a prescribed signal via the antenna and the array antenna in a system of transmission and reception at a single frequency, such as time division duplex, as the array antenna changes the in directivity to form a plurality of directivities. The radio devices detect a plurality of received radio waves' strength to produce receive signal profiles, respectively, indicating a plurality of strength profiles. The radio devices multivalue strength of the receive signal profiles, respectively, and generate private keys having the multivalued plurality of values serving as a bit pattern.

Growing community of inventors

Kyotanabe, Japan

Hideichi Sasaoka