Communication system

• US 7,542,729 B2
• Filed: 10/05/2007
• Issued: 06/02/2009
• Est. Priority Date: 03/26/1992
• Status: Expired due to Fees

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Oshima, Mitsuaki
• Primary Examiner(s): TRINH, TAN H
• Application Number:
  US11/905,978
• Publication Number:
  US 20080043870A1
• Time in Patent Office: 606 Days
• Field of Search: 455/73, 455/91, 455/205, 455/130, 455/550.1, 455/131, 455/88, 375/219, 375/260, 375/261, 375/264, 375/270, 375/301, 375/280, 375/298, 375/308, 375/324, 375/265, 370/208
• US Class Current: 455/73
• CPC Class Codes: H03M 13/256 with trellis coding, e.g. with convolutional codes and TCM
• CPC Class Codes: H03M 13/35 Unequal or adaptive error protection, e.g. by providing a different level of protection according to significance of source information or by adapting the coding according to the change of transmission channel characteristics
• CPC Class Codes: H04L 1/0041 Arrangements at the transmitter end
• CPC Class Codes: H04L 1/0042 Encoding specially adapted to other signal generation operation, e.g. in order to reduce transmit distortions, jitter, or to improve signal shape H04L1/0067 takes precedence
• CPC Class Codes: H04L 1/0047 Decoding adapted to other signal detection operation in conjunction with sequence estimation or equalization H04L25/03286
• CPC Class Codes: H04L 1/0054 Maximum-likelihood or sequential decoding, e.g. Viterbi, Fano, ZJ algorithms
• CPC Class Codes: H04L 1/0057 Block codes H04L1/0061, H04L1/0064 take precedence
• CPC Class Codes: H04L 1/006 Trellis-coded modulation
• CPC Class Codes: H04L 1/0065 Serial concatenated codes
• CPC Class Codes: H04L 1/007 Unequal error protection for format H04L1/0078; for codes per se H03M13/35
• CPC Class Codes: H04L 2027/0036 using a recovered symbol clock
• CPC Class Codes: H04L 2027/0053 Closed loops
• CPC Class Codes: H04L 2027/0067 Phase error detectors
• CPC Class Codes: H04L 27/02 Amplitude-modulated carrier systems, e.g. using on-off keying; Single sideband or vestigial sideband modulation H04L27/32 takes precedence
• CPC Class Codes: H04L 27/04 Modulator circuits; Transmitter circuits
• CPC Class Codes: H04L 27/183 Multiresolution systems
• CPC Class Codes: H04L 27/2602 Signal structure
• CPC Class Codes: H04L 27/2603 Signal structure ensuring backward compatibility with legacy system
• CPC Class Codes: H04L 27/2604 Multiresolution systems by means of multiresolution subcarriers H04L27/183, H04L27/3488
• CPC Class Codes: H04L 27/34 Amplitude- and phase-modulated carrier systems, e.g. quadrature-amplitude modulated carrier systems
• CPC Class Codes: H04L 27/3488 : Multiresolution systems
• CPC Class Codes: H04L 27/36 : Modulator circuits; Transmitter circuits
• CPC Class Codes: H04L 27/38 : Demodulator circuits; Receiver circuits
• CPC Class Codes: H04L 27/3854 : using a non - coherent carrier, including systems with baseband correction for phase or frequency offset
• CPC Class Codes: H04L 5/0044 : allocation of payload
• CPC Class Codes: H04N 19/36 : Scalability techniques involving formatting the layers as a function of picture distortion after decoding, e.g. signal-to-noise [SNR] scalability
• CPC Class Codes: H04N 19/37 : with arrangements for assigning different transmission priorities to video input data or to video coded data
• CPC Class Codes: H04N 19/60 : using transform coding
• CPC Class Codes: H04N 19/63 : using sub-band based transform, e.g. wavelets
• CPC Class Codes: H04N 21/234327 : by decomposing into layers, e.g. base layer and one or more enhancement layers
• CPC Class Codes: H04N 21/2365 : Multiplexing of several video streams
• 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 21/426 : Internal components of the client ; Characteristics thereof H04N5/44 takes precedence
• CPC Class Codes: H04N 21/4347 : Demultiplexing of several video streams
• 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 21/440227 : by decomposing into layers, e.g. base layer and one or more enhancement layers
• CPC Class Codes: H04N 21/4621 : Controlling the complexity of the content stream or additional data, e.g. lowering the resolution or bit-rate of the video stream for a mobile client with a small screen arrangements for using the results of monitoring on user's side in broadcast systems H04H60/65; flow control in packet networks H04L47/10
• CPC Class Codes: H04N 21/64792 : Controlling the complexity of the content stream, e.g. by dropping packets intermediate media network packet handling H04L65/765; proxy provisioning conversion or adaptation for reducing the amount or size of exchanged application data H04L67/5651; negotiation of resources in wireless networks H04W28/16
• CPC Class Codes: H04N 5/455 : Demodulation-circuits
• CPC Class Codes: H04N 5/46 : for receiving on more than one standard at will deflecting circuits of multi-standard receivers H04N3/27
• CPC Class Codes: H04N 7/015 : High-definition television systems
• CPC Class Codes: H04N 7/24 : Systems for the transmission of television signals using pulse code modulation H04N21/00 takes precedence

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. At the receiver side, the first and/or second data streams can be reconstructed from a received signal. Furthermore, a communication system based on an OFDM system is utilized for data transmission of a plurality of subchannels, wherein the subchannels are differentiated by changing the length of a guard time slot or a carrier wave interval of a symbol transmission time slot, or changing the transmission electric power of the carrier.

Claims

1. A signal transmission apparatus comprising:

a modulator operable to modulate first carriers by a first data stream according to an m-level PSK or an m-level QAM to produce first modulated carriers, and modulate second carriers by a second data stream according to an n-level PSK or an n-level QAM to produce second modulated carriers, wherein adjacent two carriers of the first and second carriers are quadrate with each other, and wherein n is an integer greater than m;

a converter operable to convert the first modulated carriers into a first OFDM symbol according to Orthogonal Frequency Division Multiplexing, and add a first guard interval to the first OFDM symbol to produce a first OFDM signal, and to convert the second modulated carriers into a second OFDM symbol according to Orthogonal Frequency Division Multiplexing, and add a second guard interval to the second OFM symbol to produce a second OFDM signal, wherein time periods of the first and second guard intervals are selectable; and

a transmitter operable to transmit the first OFDM signal and the second OFDM signal.

2. A signal receiving apparatus comprising:

a receiver operable to receive an input signal to produce a received signal;

wherein the input signal includes a first OFDM signal and a second OFDM signal, the input signal has been converted according to Orthogonal Frequency Division Multiplexing, the first OFDM signal includes a first guard interval and a first OFDM symbol, the second OFDM signal includes a second guard interval and a second OFDM symbol, the first OFDM symbol includes information of first carriers, the second OFDM symbol includes information of second carriers, the first carriers have been modulated by a first data stream according to an m-level PSK or an m-level QAM, the second carriers have been modulated by a second data stream according to an n-level PSK or an n-level QAM, n is an integer greater than m, and time periods of the first and second guard interval are selectable;

a converter operable to convert the received signal into the first carriers and the second carriers according to Orthogonal Frequency Division Multiplexing; and

a demodulator operable to demodulate the first carriers to produce the first data stream and demodulate the second carriers to produce the second data stream.

3. A signal transmission system comprising:

a signal transmission apparatus comprising;

a modulator operable to modulate first carriers by a first data stream according to an m-level PSK or an m-level QAM to produce first modulated carriers, and modulate second carriers by a second data stream according to an n-level PSK or an n-level QAM to produce second modulated carriers, wherein adjacent two carriers of the first and second carriers are quadrate with each other, and wherein n is an integer greater than m;

a frequency-time converter operable to convert the first modulated carriers into a first OFDM symbol according to Orthogonal Frequency Division Multiplexing, and add a first guard interval to the first OFDM symbol to produce a first OFDM signal, and to convert the second modulated carriers into a second OFDM symbol according to Orthogonal Frequency Division Multiplexing, and add a second guard interval to the second OFDM symbol to produce a second OFDM signal, wherein time periods of the first and second guard intervals are selectable; and

a transmitter operable to transmit the first OFDM signal and the second OFDM signal;

a signal receiving apparatus comprising;

a time-frequency converter operable to convert the first OFDM signal into the first carriers and convert the second OFDM signal into the second carriers according to Orthogonal Frequency Division Multiplexing; and

a demodulator operable to demodulate the first carriers to produce the first data stream and demodulate the second carriers to produce the second data stream.

4. A signal transmission method comprising:

modulator, modulating first carriers by a first data stream according to an m-level PSK or an m-level QAM to produce first modulated carriers, and modulating second carriers by a second data stream according to an n-level PSK or an n-level QAM to produce second modulated carriers, wherein adjacent two carriers of the first and second carriers are quadrate with each other, and wherein n is an integer greater than m;

converter, converting the first modulated carriers into a first OFDM symbol according to Orthogonal Frequency Division Multiplexing, and adding a first guard interval to the first OFDM symbol to produce a first OFDM signal, and converting the second modulated carriers into a second OFDM symbol according to Orthogonal Frequency Division Multiplexing, and adding a second guard interval to the second OFDM symbol to produce a second OFDM signal, wherein time periods of the first and second guard intervals are selectable; and

transmitter, transmitting the first OFDM signal and the second OFDM signal.

5. A signal receiving method comprising:

receiver, receiving an input signal to produce a received signal;

wherein the input signal includes a first OFDM signal and a second OFDM signal, an and a guard interval, the input signal having been converted according to Orthogonal Frequency Division Multiplexing, the first OFDM signal includes a first guard interval and a first OFDM symbol, the second OFDM signal includes a second guard interval and a second OFDM symbol, the first OFDM symbol includes information of first carriers, the second OFDM symbol includes information of second carriers, the first carriers have been modulated first data stream according to an m-level PSK or an m-level QAM, the second carriers have been the modulated by a second data stream according to an n-level PSK or an n-level QAM, n is an integer greater than m, and periods time periods of the first and second guard interval are selectable;

converter, converting the received signal into the first carriers and the second carriers according to Orthogonal Frequency Division Multiplexing; and

demodulator, demodulating the first carriers to produce the first data stream and demodulating the second carriers to produce the second data stream.

6. A signal transmission and receiving method comprising a signal transmission method and a signal receiving method, said signal transmission method comprising:

modulator, modulating first carriers by a first data stream according to an m-level PSK or an m-level QAM to produce first modulated carriers, and modulating second carriers by a second data stream according to an n-level PSK or an n-level QAM to produce signals second modulated carriers, wherein adjacent two carriers of the first and second carriers are quadrate with each other, and wherein the first value and n is an integer greater than m;

converter, converting the first modulated carriers into a first OFDM symbol according to Orthogonal Frequency Division Multiplexing, and adding a first guard interval to the first OFDM symbol to produce a first OFDM signal, and converting the second modulated carriers into a second OFDM symbol according to Orthogonal Frequency Division Multiplexing, and adding a second guard interval to the second OFDM symbol to produce a second OFDM signal, wherein time periods of the first and second guard interval are selectable; and

modulated an and

transmitter, transmitting the first OFDM signal and the second OFDM signal;

a-the signal receiving method comprising;

converter, converting the first OFDM signal into the first carriers and converting the second OFDM signal into the second carriers according to Orthogonal Frequency Division Multiplexing; and

demodulator, demodulating the first carriers stream to produce the first data stream and demodulating the second carriers to produce the second data stream.