Communication system

• US 7,302,007 B1
• Filed: 11/06/2000
• Issued: 11/27/2007
• Est. Priority Date: 03/26/1992
• Status: Expired due to Fees

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Oshima, Mitsuaki
• Primary Examiner(s): Ha; Dac V.
• Application Number:
  US09/705,844
• Time in Patent Office: 2,577 Days
• Field of Search: 375/260, 375/261, 375/264, 375/265, 375/296, 375/298, 375/302, 375/308, 375/324, 375/340
• US Class Current: 375/261
• CPC Class Codes: H04L 27/183 Multiresolution systems
• CPC Class Codes: H04L 27/3488 Multiresolution systems
• CPC Class Codes: H04N 21/2383 Channel coding or modulation of digital bit-stream, e.g. QPSK modulation arrangements for detecting or preventing errors in the information received by adapting the channel coding H04L1/0009; analogue front ends or means for connecting modulators, demodulators or transceivers to a transmission line H04L27/0002
• CPC Class Codes: H04N 21/4382 Demodulation or channel decoding, e.g. QPSK demodulation analog front ends or means for connecting modulators, demodulators or transceivers to a transmission line H04L27/0002
• CPC Class Codes: H04N 21/631 Multimode Transmission, e.g. transmitting basic layers and enhancement layers of the content over different transmission paths or transmitting with different error corrections, different keys or with different transmission protocols

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.

Claims

1. A signal transmission and receiving apparatus for transmitting and receiving a PSK modulated signal or a QAM modulated signal, the apparatus comprising a transmission apparatus and a receiving apparatus,

said transmission apparatus comprising:

a modulator operable to modulate a data stream to an n-level PSK modulated signal or an n-level QAM modulated signal, wherein n is an integer,

wherein the modulator is operable to select a value of n from a plurality of values of n; and

a transmitter operable to transmit the n-level PSK modulated signal or the n-level QAM modulated signal;

wherein the transmission power of the n-level PSK modulated signal or the n-level QAM modulated signal is determined according to information representing the selected value of n;

said receiving apparatus comprising;

a demodulator operable to demodulate the n-level PSK modulated signal or the n-level QAM modulated signal to a demodulated data stream.

2. A signal transmission apparatus for transmitting a PSK modulated signal or a QAM modulated signal, the apparatus comprising:

a modulator operable to modulate a data stream to an n-level PSK modulated signal or an n-level QAM modulated signal, wherein n is an integer,

wherein the modulator is operable to select a value of n from a plurality of values of n; and

a transmitter operable to transmit the n-level PSK modulated signal or the n-level QAM modulated signal;

wherein the transmission power of the n-level PSK modulated signal or the n-level QAM modulated signal is determined according to information representing the selected value of n.

3. A signal receiving apparatus comprising:

a receiver operable to receive a transmitted n-level PSK modulated signal or a transmitted n-level QAM modulated signal, wherein n is an integer,

wherein the value of n is selected from a plurality of values of n, and the transmission power of the transmitted n-level PSK modulated signal or the transmitted n-level QAM modulated signal is relative to information representing the selected value of n; and

a demodulator operable to demodulate the n-level PSK modulated signal or the n-level QAM modulated signal to a data stream.

4. A signal transmission and receiving method for transmitting and receiving a PSK modulated signal or a QAM modulated signal, the method comprising a transmission method and a receiving method,

said transmission method comprising:

modulating a data stream to an n-level PSK modulated signal or an n-level QAM modulated signal, wherein n is an integer,

wherein the modulating includes selecting a value of n from a plurality of values of n; and

transmitting the n-level PSK modulated signal or the n-level QAM modulated signal;

wherein the transmission power of the n-level PSK modulated signal or the n-level QAM modulated signal is determined according to information representing the selected value of n;

said receiving method comprising;

demodulating the n-level PSK modulated signal or the n-level QAM modulated signal to a demodulated data stream.

5. A signal transmission method for transmitting a PSK modulated signal or QAM modulated signal, the method comprising:

modulating a data stream to an n-level PSK modulated signal or an n-level QAM modulated signal, wherein n is an integer,

wherein the modulating includes selecting a value of n from a plurality of values of n; and

transmitting the n-level PSK modulated signal or the QAM modulated signal;

wherein the transmission power of the n-level PSK modulated signal or the n-level QAM modulated signal is determined according to information representing the selected value of n.

6. A signal receiving method comprising:

receiving a transmitted n-level PSK modulated signal or a transmitted n-level QAM modulated signal, wherein n is an integer,

wherein the value of n is selected from a plurality of values of n, and the transmission power of the transmitted n-level PSK modulated signal or the transmitted n-level QAM modulated signal is relative to information representing the selected value of n; and

demodulating the transmitted n-level PSK modulated signal or the transmitted n-level QAM modulated signal to a data stream.