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US 8,284,868 B2Granted
Modulating device and method, demodulating device and method
AssigneeElectronics and Telecommunications Research Institute
InventorsDong Kyoo Kim, Jaehwan Kim, Hyung Soo Lee, Jae Young Kim
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Abstract
A modulation device uses two base signal axes including a cosine function and two base signal axes including a sine function to modulate bit information and generate a modulation symbol. Accordingly, the frequency efficiency characteristic is improved while maintaining a great power efficiency characteristic.
Claims17
A device for modulating input bit information, comprising:
- a modulation symbol generator for modulating the bit information and generating a modulation symbol by using one first base signal axis and one second base signal axis from among a plurality of first base signal axes including a cosine function and a plurality of second base signal axes including a sine function,
- wherein the plurality of first base signal axes comprise a signal axis that is a product of the cosine function and a first pulse signal, and a signal axis that is a product of the cosine function and a second pulse signal, and the plurality of second base signal axes comprise a signal axis that is a product of the sine function and the first pulse signal, and a signal axis that is a product of the sine function and the second pulse signal,
- wherein the first pulse signal and the second pulse signal each comprise a sound signal and a silence signal, and the first pulse signal and the second pulse signal are inverted with respect to each other;
- and
- a transmitter for transmitting the generated modulation symbol.
2 more elements
A device for demodulating a received signal comprising:
- a first matched filter and a second matched filter respectively having a first filter coefficient and a second filter coefficient respectively matching a first base signal axis and a second base signal axis including a cosine function, filtering the received signal with bandwidths having the first filter coefficient and the second filter coefficient, and outputting filtered signals;
- a third matched filter and a fourth matched filter respectively having a third filter coefficient and a fourth filter coefficient respectively matching a third base signal axis and a fourth base signal axis including a sine function, filtering the received signal with bandwidths having the third filter coefficient and the fourth filter coefficient, and outputting filtered signals;
- a signal determining unit for determining bit information transmitted by a transmitting device by using the filtered signals output by the first to fourth matched filters.
A method for modulating input bit information, comprising:
- generating a plurality of baseband symbols by mapping the bit information on a symbol;
- outputting a first pulse signal that is a product of a first baseband symbol and a cosine function;
- outputting a second pulse signal that is a product of a second baseband symbol and a sine function;
- adding the first pulse signal and the second pulse signal and outputting the added signal;
- and
- generating a modulation symbol by multiplying the added signal and a third baseband symbol.
3 more elements
A method for demodulating a received signal, comprising:
- filtering the received signal with bandwidths having a first filter coefficient and a second filter coefficient respectively matching a first base signal axis and a second base signal axis including a cosine function and a third filter coefficient and a fourth filter coefficient respectively matching a third base signal axis and a fourth base signal axis including a sine function, and outputting a filtered signal;
- and
- determining bit information transmitted by a transmitting device by using the filtered signal.
Dependencies are inferred from the claim text.