Communication system
First Claim
1. A telephone for transmitting an uplink signal to a base station and receiving a first downlink signal and a second downlink signal from the base station, comprising:
- a modulator operable to modulate a data stream according to a QPSK to produce a modulated signal;
a transmitter operable to transmit the modulated signal as the uplink signal;
a receiver operable to receive the first downlink signal and the second downlink signal, wherein the first downlink signal has information of a first data stream and the second downlink signal has information of a second data stream, the first downlink signal is modulated according to a QPSK and the second downlink signal is scrambled and modulated according to an n-level QAM or an n-level PSK, wherein the first data stream includes information representing the value of n;
a descrambler operable to descramble the second downlink signal to produce a descrambled second downlink signal;
a demodulator operable to demodulate the first downlink signal to produce a demodulated first data stream and demodulate the descrambled second downlink signal to produce a demodulated second data stream, wherein the demodulated second data stream is produced according to the value of n;
a first error correction code (ECC) decoder operable to ECC decode the demodulated first data stream to produce the first data stream; and
a second error correction code (ECC decoder operable to ECC decode the demodulated second data stream to produce the second data stream;
wherein a coding scheme of the first ECC decoder is different from a coding scheme of the second ECC decoder, and wherein a second error correction code rate is changeable.
1 Assignment
0 Petitions
Accused Products
Abstract
At the transmitter side, carrier waves are modulated according to an input signal for producing relevant signal points in a signal space diagram. The input signal is divided into, two, first and second, data streams. The signal points are divided into signal point groups to which data of the first data stream are assigned. Also, data of the second data stream are assigned to the signal points of each signal point group. A difference in the transmission error rate between first and second data streams is developed by shifting the signal points to other positions in the space diagram. At the receiver side, the first and/or second data streams can be reconstructed from a received signal. In TV broadcast service, a TV signal is divided by a transmitter into, low and high, frequency band components which are designated as a first and a second data stream respectively. Upon receiving the TV signal, a receiver can reproduce only the low frequency band component or both the low and high frequency band components, depending on its capability.
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Citations
8 Claims
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1. A telephone for transmitting an uplink signal to a base station and receiving a first downlink signal and a second downlink signal from the base station, comprising:
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a modulator operable to modulate a data stream according to a QPSK to produce a modulated signal; a transmitter operable to transmit the modulated signal as the uplink signal; a receiver operable to receive the first downlink signal and the second downlink signal, wherein the first downlink signal has information of a first data stream and the second downlink signal has information of a second data stream, the first downlink signal is modulated according to a QPSK and the second downlink signal is scrambled and modulated according to an n-level QAM or an n-level PSK, wherein the first data stream includes information representing the value of n; a descrambler operable to descramble the second downlink signal to produce a descrambled second downlink signal; a demodulator operable to demodulate the first downlink signal to produce a demodulated first data stream and demodulate the descrambled second downlink signal to produce a demodulated second data stream, wherein the demodulated second data stream is produced according to the value of n; a first error correction code (ECC) decoder operable to ECC decode the demodulated first data stream to produce the first data stream; and a second error correction code (ECC decoder operable to ECC decode the demodulated second data stream to produce the second data stream; wherein a coding scheme of the first ECC decoder is different from a coding scheme of the second ECC decoder, and wherein a second error correction code rate is changeable. - View Dependent Claims (2)
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3. A telephone for transmitting an uplink signal to a base station and receiving a first downlink signal and a second downlink signal from the base station, comprising:
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a modulator operable to modulate a data stream according to a QPSK to produce a modulated signal; a multiplexer operable to convert the modulated signal to a CDMA converted signal according to CDMA; a transmitter operable to transmit the CDMA converted signal as the uplink signal; a receiver operable to receive the first downlink signal and the second downlink signal, wherein the first downlink signal has information of a first data stream and the second downlink signal has information of a second data stream, the first downlink signal is modulated according to a QPSK and the second downlink signal is scrambled and modulated according to an n-level QAM or an n-level PSK, wherein the first data stream includes information renresenting the value of n; a de-multiplexer operable to convert the first downlink signal to a de-multiplexed first downlink signal and convert the second downlink signal to a de-multiplexed second downlink signal according to CDMA; a descrambler operable to descramble the de-multiplexed second downlink signal to produce a descrambled second downlink signal; a demodulator operable to demodulate the de-multiplexed first downlink signal to produce a demodulated first data stream and demodulated the descrambled second downlink signal to produce a demodulated second data stream, wherein the demodulated second data stream is produced according to the value of n; a first error correction code (ECC) decoder operable to ECC decode the demodulated first data stream to produce the first data stream; and a second error correction code (ECC) decoder operable to ECC decode the demodulated second data stream to produce the second data stream; wherein a coding scheme of the first ECC decoder is different from a coding scheme of the second ECC decoder, and wherein a second error correction code rate is changeable. - View Dependent Claims (4)
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5. A transmission and receiving method for transmitting an uplink signal to a base station and receiving a first downlink signal and a second downlink signal from the base station, comprising:
when the uplink signal is transmitted from a telephone to the base station; modulating a data stream according to a QPSK to produce a modulated signal; and transmitting the modulated signal as the uplink signal; and
when the first and second downlink signals are transmitted from the base station to the telephone;receiving the first downlink signal and the second downlink signal, wherein the first downlink signal has information of a first data stream and the second downlink signal has information of a second data stream, the first downlink signal is modulated according to a QPSK and the second downlink signal is scrambled and modulated according to an n-level QAM or an n-level PSK, wherein the first data stream includes information representing the value of n; descrambling the second downlink signal to produce a descrambled second downlink signal; and demodulating the first downlink signal to produce a demodulated first data stream and demodulating the descrambled second downlink signal to produce a demodulated second data stream, wherein the demodulated second data stream is produced according to the value of n. - View Dependent Claims (6)
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7. A transmission and receiving method for transmitting an uplink signal to a base station and receiving a first downlink signal and a second downlink signal from the base station, comprising:
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when the uplink signal is transmitted from a telephone to the base station; modulating a data stream according to a QPSK to produce a modulated signal; multiplexing the modulated signal to produce a CDMA converted signal according to CDMA; and transmitting the CDMA converted signal as the uplink signal; and when the first and second downlink signals are transmitted from the base station to the telephone; receiving the first downlink signal and the second downlink signal, wherein the first downlink signal has information of a first data stream and the second downlink signal has information of a second data stream, the first downlink signal is modulated according to a QPSK and the second downlink signal is scrambled and modulated according to an n-level QAM or an n-level PSK, wherein the first data stream includes information representing the value of n; de-multiplexing the first downlink signal to produce a de-multiplexed first downlink and de-multiplexing the second downlink signal to produce a de-multiplexed second downlink signal, according to CDMA; and descrambling the de-multiplexed second downlink signal to produce a descrambled second downlink signal; demodulating the de-multiplexed first downlink signal to produce a demodulated first data stream and demodulating the descrambled second downlink signal to produce a demodulated second data stream, wherein the demodulated second data stream is produced according to the value of n; performing first error correction code (ECC) decoding of the demodulated first data stream to produce the first data stream; and performing second error correction code (ECC) decoding of the demodulated second data stream to produce the second data stream; wherein a coding scheme of the first ECC decoding is different from a coding scheme of the second ECC decoding, and wherein a second error correction code rate is changeable. - View Dependent Claims (8)
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Specification