Ofdm modem system

• US 20030031120A1
• Filed: 08/27/2002
• Published: 02/13/2003
• Est. Priority Date: 09/07/2000
• Status: Active Grant

• Current Assignee: Redwood Technologies, LLC (Dominion Harbor Enterprises, LLC)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Ikeda, Yasunari, Miyato, Yoshikazu
• Granted Patent: US 7,327,669 B2
• Time in Patent Office: Days
• US Class Current: 370/203
• CPC Class Codes: H04L 1/0057 Block codes H04L1/0061, H04L1/0064 take precedence
• CPC Class Codes: H04L 1/0059 Convolutional codes
• CPC Class Codes: H04L 1/0065 Serial concatenated codes
• CPC Class Codes: H04L 2027/0028 at passband only
• CPC Class Codes: H04L 25/03866 using scrambling
• CPC Class Codes: H04L 25/20 Repeater circuits; Relay circuits
• CPC Class Codes: H04L 27/2627 Modulators
• CPC Class Codes: H04L 27/26524 Fast Fourier transform [FFT] or discrete Fourier transform [DFT] demodulators in combination with other circuits for demodulation

Abstract

A radio relay system (1) comprises a wireless camera (11) and a signal receiving relay station (12). The wireless camera (11) wirelessly transmits signals to the signal receiving relay station (12) by using the OFDM modulation method. The wireless camera (11) and the signal receiving relay station (12) perform energy dispersion at the time of transmission-line-coding/decoding a transport stream. The PRBS seed (initial value) to be used for the energy dispersion can be externally modified and the user can arbitrarily select a value for the seed.

Claims

1. An OFDM modulator for performing orthogonal frequency division multiplexing (OFDM) modulation on a digital data series comprising:

an energy dispersion means for dispersing energy for the digital data series by means of a pseudo-random number series; and

an initial value selecting means for making the initial value of said pseudo-random number series variable.

2. The OFDM modulator according to claim 1, further comprising:

a means for transmitting information indicating said initial value of said pseudo-random number series selected by said initial value selected means.

3. An OFDM demodulator for demodulating the digital data series from an orthogonal frequency division mulitplexed (OFDM) signal comprising:

an energy inverse dispersion means for performing energy inverse dispersion for the demodulated digital data series by means of a pseudo-random number series; and

an initial value selecting means for making the initial value of said pseudo-random number series variable according to the external input.

4. An OFDM demodulator according to claim 3, further comprising:

a restoring means for restoring information indicating an initial value of said pseudo-random number series as transmitted to it;

said initial value selecting means being adapted to select an initial value of said pseudo-random number series on the basis of the information indicating said initial value as restored by said restoring means.

5. An OFDM transmission/reception system for radio transmission of an orthogonal frequency division multiplexed (OFDM) signal comprising:

a transmitter having an energy dispersion means for dispersing energy for an digital data series by means of a pseudo-random number series, an initial value selection means for making the initial value of said pseudo-random number series variable, a modulation means for performing orthogonal frequency division multiplexing (OFDM) modulation for the energy inverse-dispersed digital data series and a transmission means for wirelessly transmitting the OFDM signal generated by the OFDM modulation; and

a receiver having a reception means for receiving said OFDM signal wirelessly transmitted from said transmitter, a modulation/demodulation means for performing orthogonal frequency division multiplexing (OFDM) demodulation for the received OFDM signal, an energy inverse dispersion means for inversely dispersing energy for the demodulated digital data series by means of a pseudo-random number series and an initial value selection means for making the initial value of said pseudo-random number series variable, a same value being selected for the initial value of the pseudo-random number series of said transmitter and for the initial value of the pseudo-random number series of said receiver.

6. The OFDM transmission/reception system according to claim 5, wherein said initial value is transmitted between said transmitter and said receiver.