A multicarrier digital transmission system for communicating bits of digital data over set of different frequencies in a transmission channel's frequency band, each frequency constituting a subchannel of the transmission channel's frequency band, the multicarrier digital transmission system comprising:
- a. an emitter (100) for receiving a digital input data stream d(n) and for emitting therefrom a digital multicarrier signal Se(n), the emitter (100) including:
- i. a serial/parallel converter (110), which operates responsive to a synchronization and service data signal scdatar, for splitting the digital input data stream d(n) into a number of substreams of digital data di, each of the digital substreams di being assigned to at least one used subchannel of the transmission channel's frequency band;
- ii. an OQAM modulator (120) for receiving the digital substreams di produced by the serial/parallel converter (110), and for producing from the digital substreams di, responsive to the synchronization and service data signal scdatar, a set of N sequences of OQAM modulated quantized signal samples xi;
- iii. synchro+data unit (150) for generating, responsive to service data scdatae, a transmitted synchronization and service data signal xis that is assigned to at least one synchronization subchannel of the transmission channel's frequency band;
- and
- iv. a synthesis filter bank (130) having inputs for receiving:
- A. from the OQAM modulator (120) the set of N sequences of quantized signal samples xi, and
- B. from the synchro+data unit (150) the transmitted synchronization and service data signal xis;
- and
- for producing, from the received set of N sequences of quantized signal samples xi and from the received transmitted synchronization and service data signal xis, the multicarrier output digital signal Se(n);
- and
- b. a receiver (200) for receiving an input signal Sr(n) and for producing therefrom an output data stream d′(n), the receiver including:
- i. an analysis filter bank (210) for receiving the input signal Sr(n), and for producing:
- A. from used subchannels of the input signal Sr(n) a set of sequences xir equal to the number of used subchannels;
- and
- B. from the at least one synchronization subchannel of the input signal Sr(n) a received synchronization and service data signal xisr;
- ii. a subchannel equalizer (220) for receiving the sequences xir produced by the analysis filter bank (210) and, for producing from the received sequence xir an output signal vi, wherein the subchannel equalizer (220) in producing the output signal vi adjusts both the amplitude and phase of the received sequence xir by processing the received sequence xir through a cascade of;
- A. an amplitude equalizer (221);
- B. a phase and residual amplitude equalizer (222);
- and
- C. a fine equalizer (223);
- iii. a data extractor (230) which receives the signal vi from the subchannel equalizer (220) and, responsive to the service data scdatae, produces a binary representation dir of the received signal vi by quantizing real and imaginary parts thereof;
- iv. a parallel-to-serial converter (240) for receiving the binary representations dir from the data extractor (230) and for producing therefrom the output data stream d′(n);
- iv. a synchro processor (270) for receiving from the analysis filter bank (210) the received synchronization and service data signal xisr and for detecting therein at least the synchronization and service data signal scdatar to which the serial/parallel converter (110) and the OQAM modulator (120) respond;
- and
- vi. a capacity +bit assign (250) which receives from the phase and residual amplitude equalizer (222) of the subchannel equalizer (220) an error signal eip and from the data extractor (230) an error signal ei, and from the error signals eip and ei:
- A. for every used subchannel estimates a reference amplitude ra which the capacity+bit assign (250) transmits to the subchannel equalizers (220);
- and
- B. decides a number of bits to be assigned to every used subchannel which the capacity+bit assign (250) transmits via the service data scdatae both to data extractor (230) and to the synchro+data unit (150).