Patent ID: 7545845

Claim:
A radio communication system comprising: a radio transmitter including encoding means for encoding a digital signal to be transmitted, and a transmission antenna which transmits the signal encoded by said encoding means; and a radio receiver including a reception antenna which receives the transmitted signal, and decoding means for performing decoding corresponding to encoding for the signal received by said reception antenna and restoring the digital signal, wherein communication is performed without using any carrier; wherein said encoding means comprises spreading means for performing a spread spectrum process by multiplying the digital signal to be transmitted by a spreading code, and signal generation means for generating an impulse signal in response to rise and fall of a signal spread by said spreading means and outputting the impulse signal to said transmission antenna, and; wherein said decoding means comprises despreading means for performing despreading for the signal received by said reception antenna by using a spreading code corresponding to a differentiated spread signal, and peak detection means for detecting a peak of the signal despread by said despreading means and restoring the digital signal, wherein ΔS is the differentiated spread signal, C is a spreading code corresponding to the spread signal S, P is a correlation value between the differentiated spread signal ΔS and the spreading code C, and M is a code length of the spreading code C, P ≈ ∑ k = 1 M ⁢ ⁢ ( Δ ⁢ ⁢ S k · ∑ r = k M ⁢ ⁢ C r ) is established.