Signal transmission method

Claim 2

Signal transmission method according to the principle of quadrature amplitude modulation, comprising the steps of: in a transmitter (a) sampling digital data in predetermined time intervals T; (b) forming a transmit signal by feeding the digital data to a pulse shaper, said pulse shaper having a given unit pulse response r(t); (c) amplitude-modulating a carrier oscillation by the transmit signal; (d) transmitting said amplitude-modulated carrier oscillation via a channel, said channel having a unit pulse response h(t) and superimposing an additive white noise w(t); in a receiver (e) demodulating the transmitted carrier oscillation into a receive signal y(t); (f) sampling said receive signal in time intervals ΔT which are small in relation to the time interval T; (g) preprocessing said sampled receive signal in a transverse channel-matched filter, said channel-matched filter being matched to a filter cascade H(t) formed by said pulse shaper and said channel as a whole, H(t)=h*r(t), where "*" stands for the convolution product; and (h) determining original digital data from the preprocessed sampled receive signal in an analysis circuit.

Claim 3

Signal transmission method according to the principle of quadrature amplitude modulation, comprising the steps of: in a transmitter (a) sampling digital data in predetermined time intervals T, and based thereon generating by that data coefficients c k ; (b) forming a transmit signal by feeding the data coefficients to a pulse shaper, said pulse shaper having a given unit pulse response r(t); (c) amplitude-modulating a carrier oscillation by the transmit signal; (d) transmitting said amplitude-modulated carrier oscillation via a channel, said channel having a unit pulse response h(t) and superimposing an additive white noise w(t); in a receiver (e) demodulating the transmitted carrier oscillation into a receive signal y(t); (f) sampling said receive signal in time intervals ΔT which are small in relation to the time interval T, and based thereon generating a sampled transmit signal y k ; (g) preprocessing said sampled receive signal y k in a transverse channel-matched filter, said channel-matched filter being matched to a filter cascade H(t) formed by said pulse shaper and said channel as a whole, H(t)=h*r(t), where * stands for the convolution product, having coefficients H(i), i=0, . . . , L c , which are determined in accordance with the principle of least error squares between the transmit signal and the receive signal, fulfilling the equations ##EQU6## where c k =data coefficient, y k =sampled transmit signal, y k =complex conjugate of y k , and c k-i =complex conjugate of c k-i ; and (h) determining original data coefficients c k from the preprocessed sampled receive signal in an analysis circuit.

Claim 4

Signal transmission method according to the principle of quadrature amplitude modulation, comprising the steps of: in a transmitter (a) sampling digital data in predetermined time intervals T, and based thereon generating by that data coefficients c k ; (b) forming a transmit signal by feeding the data coefficients to a pulse shaper, said pulse shaper having a given unit pulse response r(t); (c) amplitude-modulating a carrier oscillation by the transmit signal; (d) transmitting said amplitude-modulated carrier oscillation via a channel, said channel having a unit pulse response h(t) and superimposing an additive white noise w(t); in a receiver (e) demodulating the transmitted carrier oscillation into a receive signal y(t); (f) sampling said receive signal in time intervals ΔT which are small in relation to the time interval T, and based thereon generating a sampled transmit signal y k ; (g) preprocessing said sampled receive signal y k in a transverse channel-matched filter, said channel-matched filter being matched to a filter cascade H(t) formed by said pulse shaper and said channel as a whole, H(t)=h*r(t), where * stands for the convolution product, having coefficients H(i), i=0, . . . , L c , which are determined in accordance with the principle of least error squares between the transmit signal and the receive signal, fulfilling the equations ##EQU6## where c k =data coefficient, y k =sampled transmit signal, y k =complex conjugate of y k , and c k-i =complex conjugate of c k-i ; and (h) determining original data coefficients c k from the preprocessed sampled receive signal in an analysis circuit.

Claim 5

Signal transmission method as claimed in claim 2, using data coefficients for forming the transmit signal and for preprocessing the sampled receive signal, which coefficients correspond to a predetermined sequence of digital data known to the transmitter and the receiver.

Claim 6

Signal transmission method as claimed in claim 2, wherein the filter cascade used for preprocessing is periodically estimated.

Claim 7

Signal transmission method according to the principle of quadrature amplitude modulation, comprising the steps of: in a transmitter (a) sampling digital data in predetermined time intervals T, and based thereon generating data coefficients c k ; (b) forming a transmit signal by feeding the data coefficients to a pulse shaper, said pulse shaper having a given unit pulse response r(t); (c) amplitude-modulating a carrier oscillation by the transmit signal; (d) transmitting said amplitude-modulated carrier oscillation via a channel, said channel having a unit pulse response h(t) and superimposing an additive white noise w(t); in a receiver (e) demodulating the transmitted carrier oscillation into a receive signal y(t); (f) sampling said receive signal in time intervals ΔT which are small in relation to the time interval T, generating by that a sampled transmit signal y k ; (g) feeding said sampled receive signal into a channel estimating circuit controlling a transverse channel-matched filter by calculating coefficients H(i), i=0, . . . , Lc, which are determined in accordance with the principle of least error squarres between the transmit signal and the receive signal, said coefficients H(i) fulfilling the equations, ##EQU7## where c k =data coefficient, y k =sampled transmit signal, y k =complex conjugate of y k , and c k-i =complex conjugate of c k-i ; (h) preprocessing said sampled receive signal in the transverse channel-matched filter, said channel-matched filter being matched to a filter cascade H(t) formed by said pulse shaper and said channel as a whole, H(t)=h*r(t), where * stands for the convolution product, and using said coefficients H(i), i=0, . . . , Lc; (i) determining original data coefficients c k from the preprocessed sampled receive signal in an analysis circuit; and (k) feeding back the determined data coefficients c k to the channel estimating circuit.

Claim 8

Signal transmission method according to the principle of quadrature amplitude modulation, comprising the steps of: in a transmitter (a) sampling digital data in predetermined time intervals T, and based thereon generating data coefficients c k ; (b) forming a transmit signal by feeding the data coefficients to a pulse shaper, said pulse shaper having a given unit pulse response r(t); (c) amplitude-modulating a carrier oscillation by the transmit signal; (d) transmitting said amplitude-modulated carrier oscillation via a channel, said channel having a unit pulse response h(t) and superimposing an additive white noise w(t); in a receiver (e) demodulating the transmitted carrier oscillation into a receive signal y(t); (f) sampling said receive signal in time intervals ΔT which are small in relation to the time interval T, generating by that a sampled transmit signal y k ; (g) feeding said sampled receive signal into a channel estimating circuit controlling a transverse channel-matched filter by calculating coefficients H(i), i=0, . . . , Lc, which are determined in accordance with the principle of least error squarres between the transmit signal and the receive signal, said coefficients H(i) fulfilling the equations, ##EQU7## where c k =data coefficient, y k =sampled transmit signal, y k =complex conjugate of y k , and c k-i =complex conjugate of c k-i ; (h) preprocessing said sampled receive signal in the transverse channel-matched filter, said channel-matched filter being matched to a filter cascade H(t) formed by said pulse shaper and said channel as a whole, H(t)=h*r(t), where * stands for the convolution product, and using said coefficients H(i), i=0, . . . , Lc; (i) determining original data coefficients c k from the preprocessed sampled receive signal in an analysis circuit; and (k) feeding back the determined data coefficients c k to the channel estimating circuit.

Claim 9

Signal transmission method as claimed in claim 5, comprising the step of determining the channel unit pulse response h(t) by convoluting an estimation of the filter cascade H(t) with a unit pulse response r -1 (t) which is inverse to the unit pulse response r(t) of the pulse shaper.