Method to determine a channel characteristic, and discrete wavelet transmitter and receiver to perform the method
View Patent ↗To determine the channel characteristic of a channel (CHANNEL) between a transmitter (TX) and a receiver (RX), a predetermined periodic signal of pulse amplitude modulated symbols is modulated on waveforms by a cosine modulated filter bank (DWMT MOD) in the transmitter (TX), and the waveforms are transmitted over the channel (CHANNEL). In the receiver (RX), the received pulse amplitude modulated symbols are demodulated from the waveforms by a cosine modulated filter bank (DWMT DEMOD), pairs of the received pulse amplitude modulated symbols are combined to form received quadrature amplitude modulated symbols, and the received quadrature amplitude modulated symbols are divided by the transmitted predetermined pulse amplitude modulated symbols considered pairwise as transmit quadrature amplitude modulated symbols. So, samples of the channel characteristic are generated.
1. A method to determine samples of an estimated channel characteristic of a channel between a transmitter and a receiver, wherein said method comprises:
generating a periodic signal of predetermined transmit pulse amplitude modulated symbols;
modulating waveforms with said periodic signal of predetermined transmit pulse amplitude modulated symbols in a transmit cosine modulated filter bank in said transmitter;
transferring the modulated waveforms from said transmitter to said receiver over said channel;
demodulating said modulated waveforms in a cosine modulated filter bank in said receiver to recover said periodic signal of predetermined transmit pulse amplitude modulated symbols as received pulse amplitude modulated symbols;
combining pairs of said received pulse amplitude modulated symbols to form received quadrature amplitude modulated symbols; and
dividing said received quadrature amplitude modulated symbols by transmit quadrature amplitude modulated symbols formed by combining pairs of predetermined transmit pulse amplitude modulated symbols to thereby generate said samples of said estimated channel characteristic.
2. The method to determine samples of an estimated channel characteristic according to claim 1 , wherein said method further comprises inverse Fourier transforming said samples of said estimated channel characteristic.
3. A discrete wavelet multi tone receiver comprising:
a receive cosine modulated filter bank adapted to demodulate waveforms modulated by a transmit cosine modulated filter bank to recover a periodic signal of predetermined transmit pulse amplitude modulated symbols as received pulse amplitude modulated symbols,
means to combine pairs of said received pulse amplitude modulated symbols to form received quadrature amplitude modulated symbols, and
means to divide said received quadrature amplitude modulated symbols by transmit quadrature amplitude modulated symbols formed by combining pairs of predetermined transmit pulse amplitude modulated symbols to thereby generate samples of an estimated channel characteristic of a channel between a transmitter and said discrete wavelet multi tone receiver whenever said periodic signal of predetermined transmit pulse amplitude modulated symbols are transferred.
4. The discrete wavelet multi tone receiver according to claim 3 ,
wherein said discrete wavelet multi tone receiver further comprises an inverse Fourier transformer, adapted to inverse Fourier transform said samples of said estimated channel characteristic.
5. The discrete wavelet multi tone receiver according to claim 3 , wherein said means to combine pairs of said received pulse amplitude modulated symbols is a quadrature amplitude modulated symbol interpreter.
6. The discrete wavelet multi tone receiver according to claim 5 , wherein said quadrature amplitude modulated symbol interpreter receives decoded pulse amplitude modulated symbols from a pulse amplitude modulated symbol decoder.
7. The discrete wavelet multi tone receiver according to claim 3 , wherein said means to divide said received quadrature amplitude modulated symbols is a quadrature amplitude modulated symbol divider.
8. A system comprising:
a discrete wavelet multi tone transmitter comprising:
a transmit cosine modulated filter bank adapted to modulated waveforms with symbols, and
a pulse amplitude modulated symbol generator cascade coupled to said transmit cosine modulated filter bank, said pulse amplitude modulated symbol generator being adapted to generate a periodic signal of predetermined transmit pulse amplitude modulated symbols and to apply said periodic signal of predetermined transmit pulse amplitude modulated symbols to said transmit cosine modulated filter bank; and
a discrete wavelet multi tone receiver coupled to said discrete wavelet multi tone transmitter, said discrete wavelet multi tone receiver comprising:
a receive cosine modulated filter bank adapted to demodulate waveforms modulated by said transmit cosine modulated filter bank to recover said periodic signal of predetermined transmit pulse amplitude modulated symbols as received pulse amplitude modulated symbols,
means to combine pairs of said received pulse amplitude modulated symbols to form received quadrature amplitude modulated symbols, and
means to divide said received quadrature amplitude modulated symbols by transmit quadrature amplitude modulated symbols formed by combining pairs of predetermined transmit pulse amplitude modulated symbols to thereby generate samples of an estimated channel characteristic of a channel between the transmitter and said discrete wavelet multi tone receiver whenever said periodic signal of predetermined transmit pulse amplitude modulated symbols are transferred.
9. The system according to claim 8 , wherein said discrete wavelet multi tone receiver further comprises an inverse Fourier transformer, adapted to inverse Fourier transform said samples of said estimated channel characteristic.
10. The system according to claim 8 , wherein said means to combine pairs of said received pulse amplitude modulated symbols is a quadrature amplitude modulated symbol interpreter.
11. The system according to claim 10 , wherein said quadrature amplitude modulated symbol interpreter receives decoded pulse amplitude modulated symbols from a pulse amplitude modulated symbol decoder.
12. The system according to claim 8 , wherein said means to divide said received quadrature amplitude modulated symbols is a quadrature amplitude modulated symbol divider.