Signal transmission process

Claim 2

A signal transmission process transmitting digital data from a transmitter to a receiver according to a continuous phase modulation method, comprising the steps of: (a) converting digital data which are present as a sequence of symbols α k , which symbols have a given time interval T and may assume M values, into a symbol vector c k or M L components; (b) converting said symbol vector c k into a time-dependent scalar envelope signal v(t) using a baseband filter having a characteristic r(t) of M L components, where ##EQU18## (c) phase modulating a carrier wave according to the envelope signal v(t) and transmitting said modulated carrier wave to a receiver via a channel with a given unit pulse response h c (t), an additive, white Gaussian noise w(t) being superimposed, so that at a receiver the envelop signal v(t) is transformed into a signal y(t) of the form y(t)=h.sub.c *v(t)+w(t) , where "*" denotes a convolution product; (d) demodulating said carrier wave into said signal y(t); (e) filtering said signal y(t) by a channel specific filter of the form h c *(-t) for getting sufficient statistics in a subsequent sampling step; (f) filtering said filtered signal y(t) by an adjoined baseband filter of M L components of the form r.sup.30 (-t), wherein " + " denotes conjugate complex; (g) sampling the filtered signal produced by step (f) after the adjoined baseband filter at points of time kT, where k denotes an integer; and (h) determining, based on the sampled filtered signal produced by step (g), a sequence of estimated symbols α k by an optimization algorithm.

Claim 3

A signal transmission process transmitting digital data from a transmitter to a receiver according to a continuous phase modulation method, comprising the steps of: converting digital data which are present as a sequence of symbols α k , which symbols have a given time interval T and may assume M values, into a symbol vector c k of M L components; converting said symbol vector c k into a time-dependent scalar envelop signal v(t) using a baseband filter r(t) of M L components, where ##EQU19## phase modulating a carrier wave according to the envelope signal v(t) and transmitting said modulated carrier wave to a receiver via a channel with a given unit pulse response h c (t), an additive, white Gaussian noise w(t) being superimposed, so that at a receiver the envelope signal v(t) is transformed into a signal y(t) of the form y(t)=hc*v(t)+w(t), where "*" denotes a convolution product; demodulating said carrier wave into said signal y(t); first filtering said signal y(t) by a channel specific filter of the form h c *(-t) to produce a first filtered signal for getting sufficient statistics in a subsequent sampling step; second filtering said first filtered signal y(t) by an adjoined baseband filter of M L components of the form r.sup.+ (-t) where " + " denotes conjugate complex, thereby producing a second filtered signal; sampling the second filtered signal after the adjoined baseband filter at points at time kT, where k denotes an integer; and determining, based on the sampled second filtered signal, a sequence of estimated symbols α k by a Viterbi algorithm extended by a compensation element maximizing an increment Z n of the form, ##EQU20## where c n =symbol vector, y n =signal vector, X i =channel operator, and L c =channel interference length.

Claim 4

A signal transmission process transmitting digital data from a transmitter to a receiver according to a continuous phase modulation method, comprising the steps of: converting digital data which are present as a sequence of symbols α k , which symbols have a given time interval T and may assume M values, into a symbol vector c k of M L components; converting said symbol vector c k into a time-dependent scalar envelop signal v(t) using a baseband filter r(t) of M L components, where ##EQU19## phase modulating a carrier wave according to the envelope signal v(t) and transmitting said modulated carrier wave to a receiver via a channel with a given unit pulse response h c (t), an additive, white Gaussian noise w(t) being superimposed, so that at a receiver the envelope signal v(t) is transformed into a signal y(t) of the form y(t)=hc*v(t)+w(t), where "*" denotes a convolution product; demodulating said carrier wave into said signal y(t); first filtering said signal y(t) by a channel specific filter of the form h c *(-t) to produce a first filtered signal for getting sufficient statistics in a subsequent sampling step; second filtering said first filtered signal y(t) by an adjoined baseband filter of M L components of the form r.sup.+ (-t) where " + " denotes conjugate complex, thereby producing a second filtered signal; sampling the second filtered signal after the adjoined baseband filter at points at time kT, where k denotes an integer; and determining, based on the sampled second filtered signal, a sequence of estimated symbols α k by a Viterbi algorithm extended by a compensation element maximizing an increment Z n of the form, ##EQU20## where c n =symbol vector, y n =signal vector, X i =channel operator, and L c =channel interference length.

Claim 5

A signal transmission process transmitting digital data from a transmitter to a receiver according to a continuous phase modulation method, comprising the steps of: converting digital data which are present as a sequence of symbols α k , which symbols have a given time interval T and may assume M values, into a symbol vector c k of M L components; converting said symbol vector c k into a time-dependent scalar envelop signal v(t) using a baseband filter r(t) of M L components, where ##EQU21## phase modulating a carrier wave according to the envelope signal v(t) and transmitting said modulated carrier wave to a receiver via a channel with a given unit pulse response j c (t), an additive, white Gaussian noise w(t) being superimposed, so that at the receiver the envelope signal v(t) is transformed into a signal y(t) of the form y(t)=h.sub.c *v(t)+w(t), where "*" denotes a convolution product; demodulating said carrier wave into said signal y(t); first filtering said signal y(t) by a channel specific filter of the form h c *(-t) to produce a first filtered signal for getting sufficient statistics in a subsequent sampling step; second filtering said first filtered signal y(t) by an adjoined baseband filter of M L components of the form r.sup.+ (-t) where " + " denotes conjugate complex, thereby to generate a signal vector y(t) of M L components; sampling the signal vector y(t) at points of time kT, where k denotes an integer, thereby generating a digital signal vector y k ; and transforming said digital signal vector y k into a de-emphasized signal vector γ k using a pre-emphasis filter which functions according to the principle of lease error squares in the sense that the expectation value D({A.sub.i })=E[(γ.sub.k -X.sub.r-k.sup.c).sup.+ X.sub.r.sup.-1 (γ.sub.k -X.sub.r-k.sup.c)], where ##EQU22## γ k =de-emphasized signal vector X r =channel operator of the white channel c k =symbol vector is minimized; and determining, based on the de-emphsized signal vector γ k , a sequence of estimated symbols α k by an optimization algorithm.

Claim 6

A signal transmission process transmitting digital data from a transmitter to a receiver according to a continuous phase modulation method, comprising the steps of: converting digital data which are present as a sequence of symbols α k , which symbols have a given time interval T and may assume M values, into a symbol vector c k of M L components; converting said symbol vector c k into a time-dependent scalar envelop signal v(t) using a baseband filter r(t) of M L components, where ##EQU21## phase modulating a carrier wave according to the envelope signal v(t) and transmitting said modulated carrier wave to a receiver via a channel with a given unit pulse response j c (t), an additive, white Gaussian noise w(t) being superimposed, so that at the receiver the envelope signal v(t) is transformed into a signal y(t) of the form y(t)=h.sub.c *v(t)+w(t), where "*" denotes a convolution product; demodulating said carrier wave into said signal y(t); first filtering said signal y(t) by a channel specific filter of the form h c *(-t) to produce a first filtered signal for getting sufficient statistics in a subsequent sampling step; second filtering said first filtered signal y(t) by an adjoined baseband filter of M L components of the form r.sup.+ (-t) where " + " denotes conjugate complex, thereby to generate a signal vector y(t) of M L components; sampling the signal vector y(t) at points of time kT, where k denotes an integer, thereby generating a digital signal vector y k ; and transforming said digital signal vector y k into a de-emphasized signal vector γ k using a pre-emphasis filter which functions according to the principle of lease error squares in the sense that the expectation value D({A.sub.i })=E[(γ.sub.k -X.sub.r-k.sup.c).sup.+ X.sub.r.sup.-1 (γ.sub.k -X.sub.r-k.sup.c)], where ##EQU22## γ k =de-emphasized signal vector X r =channel operator of the white channel c k =symbol vector is minimized; and determining, based on the de-emphsized signal vector γ k , a sequence of estimated symbols α k by an optimization algorithm.

Claim 7

A signal transmission process as claimed in claim 3, wherein the sequence of estimated symbols are determined using a Viterbi algorithm.