Transmitters and receiver of spectrum spread communication system, and modulation and demodulation methods thereof
First Claim
1. A transmitter for a spread-spectrum communication system in which transmission data is subject to spectrum spreading using a predetermined number of subcarriers, comprising:
- frame generation means constructing a frame by inserting a predetermined pilot sequence in the transmission data;
data hopping means comprising;
1) a hopping pattern generating unit generating a hopping pattern switched at a predetermined hopping frequency, the hopping pattern designating a subcarrier for frequency hopping; and
2) a data selection unit outputting a plurality of subcarrier transmission signals corresponding to the plurality of subcarriers, respectively, by receiving the transmission data and outputting as a subcarrier transmission signal only the transmission data carried in a subcarrier designated by the hopping pattern, while maintaining the other subcarrier transmission signals at a zero output level, said transmitter further comprising;
inverse Fourier transform means subjecting the entirety of subcarrier transmission signals output from said data selection unit to inverse Fourier transform so as to output frequency-hopped spread-spectrum transmission signals.
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Abstract
Data hopping means is provided with a hopping generation unit 21 and a data selection unit 23, the hopping pattern generation unit 21 generating a predetermined hopping pattern, and the data selection unit 23 outputting a plurality of subcarrier transmission signals corresponding to respective subcarriers, by receiving transmission data and outputting only the data carried in the subcarrier designated by the hopping pattern as the subcarrier transmission signal, while maintaining the other subcarrier transmission signals at a zero output level. Inverse Fourier transform means subjects the entirety of subcarrier reception signals output from the data selection unit 23 to inverse Fourier transform and outputs frequency-hopped spread-spectrum transmission signals.
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Citations
21 Claims
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1. A transmitter for a spread-spectrum communication system in which transmission data is subject to spectrum spreading using a predetermined number of subcarriers, comprising:
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frame generation means constructing a frame by inserting a predetermined pilot sequence in the transmission data;
data hopping means comprising;
1) a hopping pattern generating unit generating a hopping pattern switched at a predetermined hopping frequency, the hopping pattern designating a subcarrier for frequency hopping; and
2) a data selection unit outputting a plurality of subcarrier transmission signals corresponding to the plurality of subcarriers, respectively, by receiving the transmission data and outputting as a subcarrier transmission signal only the transmission data carried in a subcarrier designated by the hopping pattern, while maintaining the other subcarrier transmission signals at a zero output level, said transmitter further comprising;
inverse Fourier transform means subjecting the entirety of subcarrier transmission signals output from said data selection unit to inverse Fourier transform so as to output frequency-hopped spread-spectrum transmission signals. - View Dependent Claims (2)
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3. A transmitter for a spread-spectrum communication system comprising:
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modulation control means determining the number of subchannels for the multiplexing of transmission data and the number of subcarriers for frequency-hopping in each of the subchannels;
serial-to-parallel converting means splitting the transmission data into subchannel transmission data for as many subchannels as determined by said modulation control means;
a plurality of subchannel modulation processing means each receiving the corresponding subchannel transmission data for independent modulation processing so as to output a plurality of subcarrier transmission signals, each of said subchannel modulation processing means comprising;
1) frame generation means constructing a frame by inserting a predetermined pilot sequence in the subchannel transmission data;
2) data modulation means subjecting the subchannel transmission data of a frame structure to a predetermined data modulation process so as to output a modulated signal;
3) time-spreading means subjecting the modulated signal to a time-spreading process by multiplying the modulated signal by a predetermined time-spreading code;
4) data hopping means outputting a plurality of subcarrier transmission signals corresponding to the respective subcarriers, by receiving the modulated signal subjected to the time-spreading process, generating a predetermined hopping pattern, and outputting as the subcarrier transmission signal only the modulated signal carried in a subcarrier designated by the hopping pattern, while maintaining the other subcarrier transmission signals at a zero output level, said transmitter further comprising;
inverse Fourier transform means subjecting the entirety of subcarrier transmission signals output from said data hopping means of said plurality of subchannel modulation processing means to inverse Fourier transform so as to output transmission signals multiplexed using said plurality of subchannels in which frequency-hopping spectrum-spreading is effected. - View Dependent Claims (4, 5, 6, 7, 18)
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8. A receiver for a spread-spectrum communication system comprising:
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Fourier transform means subjecting a spread-spectrum received signal frequency-hopped to a predetermined number of subcarriers to a Fourier transform process and outputting a predetermined number of subcarrier reception signals;
hopping reception means comprising;
1) a slot synchronization unit detecting a known pilot sequence included in the subcarrier reception signal so as to establish synchronization between a transmitter with which said receiver is communicating;
2) a hopping pattern generating unit generating a hopping pattern switched at a predetermined hopping frequency, the hopping pattern designating a subcarrier for frequency hopping; and
3) a hopping data selection unit receiving the plurality of subcarrier reception signals, selecting only the subcarrier reception signal designated by the hopping pattern and outputting the selected signal as reception data. - View Dependent Claims (9)
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10. A receiver for a spread-spectrum communication system comprising:
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Fourier transform means subjecting reception signals multiplexed using said plurality of subchannels in which frequency-hopping spectrum-spreading is effected so as to output a plurality of subcarrier reception signals;
a plurality of subchannel demodulation processing means receiving for demodulation the plurality of subcarrier reception signals belonging to a corresponding subchannel and outputting subchannel reception data in the corresponding subchannel, each of said plurality of subchannel demodulation processing means comprising;
1) hopping data reception means detecting a known pilot sequence included in the subcarrier reception signal so as to establish synchronization with a transmitter with which said receiver is communicating, generating a predetermined hopping pattern and selecting only the subcarrier reception signal designated by the hopping pattern and outputting the selected signal as the reception data;
2) time-despreading means subjecting the subchannel reception data to time despreading by multiplying the subchannel reception data by a predetermined time-spreading code;
3) RAKE combination means effecting channel estimation using the pilot sequence included in the subchannel reception data subjected to time despreading, subjecting the subchannel reception data subjected to time despreading to RAKE combination and outputting the resultant subchannel reception data, said receiver further comprising;
serial-to-parallel converting means receiving the subchannel reception data subjected to RAKE combination output from each of said subchannel demodulation processing means, combining a plurality of sets of the subchannel reception data and outputting the combined reception data. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 19)
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20. A spread-spectrum modulation and demodulation method in which transmission data is subject to spectrum spreading using a predetermined number of subcarriers, comprising the steps of:
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generating a hopping pattern switched at a predetermined hopping frequency, the hopping pattern designating a subcarrier for frequency hopping;
outputting a plurality of subcarrier transmission signals corresponding to the plurality of subcarriers, respectively, by receiving the transmission data and outputting as a subcarrier transmission signal only the transmission data carried in a subcarrier designated by the hopping pattern, while maintaining the other subcarrier transmission signals at a zero output level; and
subjecting the entirety of subcarrier transmission signals to inverse Fourier transform so as to output frequency-hopped spread-spectrum transmission signals.
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21. A spread-spectrum modulation and demodulation method comprising the steps of:
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subjecting a spread-spectrum received signal frequency-hopped to a predetermined number of subcarriers to a Fourier transform process and outputting a predetermined number of subcarrier reception signals;
generating a hopping pattern switched at a predetermined hopping frequency, the hopping pattern designating a subcarrier for frequency hopping; and
receiving the plurality of subcarrier reception signals, selecting only the subcarrier reception signal designated by the hopping pattern and outputting the selected signal as reception data.
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Specification