Partial-response-channel precoding

Claim 2

Apparatus comprising means for selecting, in response to input data, a sequence of signal points from a predetermined base constellation, means for combining each selected signal point with a feedback signal to provide a sequence of combined signal points, said feedback signal being a predetermined function of at least one previously provided one of the combined signal points, said base constellation and said function being such that ones of said combined signal points are signal points of said base constellation and the others are signal points of minimally non-overlapping lattice translates of said base constellation, and means for providing a transmit signal which represents said combined signal points, all of the combined signal points which are minimally non-overlapping lattice translates of one another being represented identically.

Claim 3

The invention of claim 1 wherein the signal points of the base constellation are points of an underlying lattice which has a point at the origin and wherein the underlying lattice can be formed as the union of non-overlapping translates of the base constellation.

Claim 4

The invention of claim 2 further comprising means for applying said transmit signal to a communication channel which introduces forced intersymbol interference, and said predetermined function is such as to counter effects of said forced intersymbol interference.

Claim 5

The invention of claim 3 wherein said providing means represents each combined signal point in said transmit signal by a particular one symbol of a predetermined transmit constellation.

Claim 6

The invention of claim 4 wherein said constellation is a shifted version of said base constellation.

Claim 7

The invention of claim 3 wherein said communication channel includes a comb filter which provides an output for each combined signal point; wherein said selecting means selects each signal point of the sequence in response to a respective subset of said input data; and wherein said predetermined function is such as to enable recovery of each subset of input data from a respective one of the outputs of said comb filter independent of any of the other outputs of said comb filter.

Claim 8

The invention of claim 1 further comprising means for applying said transmit signal to a communication channel, means for receiving said transmit signal from said communication channel, and means for processing the received transmit signal to recover said input data.

Claim 9

Apparatus comprising means for generating in response to a sequence of binary input words a sequence of transmit symbols of a predetermined transmit constellation, said binary input words having a predetermined number of different values which is substantially equal to the number of symbols of said transmit constellation, and means for transmitting said sequence of transmit symbols over a channel which has a predetermined partial-response characteristic and which provides in response to said sequence of transmit symbols a sequence of receiver symbols of an expanded receiver constellation, said generating means including means for selecting, for each of said words, a respective symbol of said transmit constellation, said selecting and said constellation being such that each word can be recovered from a respective one of said receiver symbols independent of any other one of said receiver symbols, each of said transmit symbols having at least first and second coordinates and said transmit constellation and said expanded receiver constellation being other than M 2 -ary quadrature amplitude modulation constellations.

Claim 10

Apparatus comprising means for generating in response to a sequence of binary input words a sequence of transmit symbols of a predetermined transmit constellation, said binary input words having a predetermined number of different values which is substantially equal to the number of symbols of said transmit constellation, and means for transmitting said sequence of transmit symbols over a channel which has a predetermined partial-response characteristic and which provides in response to said sequence of transmit symbols a sequence of receiver symbols of an expanded receiver constellation, said generating means including means for selecting, for each of said words, a respective symbol of said transmit constellation, said selecting and said constellation being such that each word can be recovered from a respective one of said receiver symbols independent of any other one of said receiver symbols, each of said transmit symbols having at least first and second coordinates and said transmit constellation and said expanded receiver constellation being other than M 2 -ary quadrature amplitude modulation constellations.

Claim 11

The invention of claim 8 wherein said channel includes a comb filter, each different output of said comb filter corresponding to a different one of the symbols of said expanded receiver constellation.

Claim 12

The invention of claim 8 further comprising means for recovering said input data from said sequence of receiver symbols.

Claim 13

Apparatus for use in a data communication system in which a sequence of transmit symbols selected from a predetermined transmit constellation in response to binary input data is transmitted over a communication channel having a predetermined partial-response characteristic, said binary input data having a predetermined number of different values which is substantially equal to the number of symbols of said transmit constellations, said channel providing, in response to said transmitted symbols, a sequence of receiver symbols of an expanded receiver constellation, each of said transmit and receiver symbols having at least first and second coordinates, each transmit symbol being selected for a respective binary word of said data in such a way that that binary word can be recovered from a respective one of said receiver symbols independent if any other one of said receiver symbols, said apparatus comprising means for receiving said sequence of receiver symbols, and means for recovering said data from the sequence of receiver symbols received by said means for receiving in response to stored information which associates each different receiver symbol with a different binary word value, the values of the bits of each said binary word value interdependently identifying the values of the first and second coordinates of the associated receiver symbol.

Claim 14

Apparatus for use in a data communication system in which a sequence of transmit symbols selected from a predetermined transmit constellation in response to binary input data is transmitted over a communication channel having a predetermined partial-response characteristic, said binary input data having a predetermined number of different values which is substantially equal to the number of symbols of said transmit constellations, said channel providing, in response to said transmitted symbols, a sequence of receiver symbols of an expanded receiver constellation, each of said transmit and receiver symbols having at least first and second coordinates, each transmit symbol being selected for a respective binary word of said data in such a way that that binary word can be recovered from a respective one of said receiver symbols independent if any other one of said receiver symbols, said apparatus comprising means for receiving said sequence of receiver symbols, and means for recovering said data from the sequence of receiver symbols received by said means for receiving in response to stored information which associates each different receiver symbol with a different binary word value, the values of the bits of each said binary word value interdependently identifying the values of the first and second coordinates of the associated receiver symbol.

Claim 15

The invention of claim 11 wherein said channel includes a comb filter, each different output of said comb filter corresponding to a different one of the symbols of said expanded receiver constellation.

Claim 18

The invention of claim 13 wherein the signal points of the base constellation are points of an underlying lattice which has a point at the origin and wherein the underlying lattice can be formed as the union of non-overlapping translates of the base constellation.

Claim 19

The invention of claim 13 comprising the further step of applying said transmit signal to a communication channel which introduces forced intersymbol interference, and wherein in said combining step said predetermined function is such as to counter effects of said forced intersymbol interference.

Claim 20

The invention of claim 13 wherein in said providing step all of the combined signal points which are minimally non-overlapping lattice translates of one another are represented in said transmit signed by a particular one symbol of a predetermined transmit constellation.

Claim 21

The invention of claim 16 wherein said transmit constellation is a shifted version of said base constellation.

Claim 22

The invention of claim 16 wherein said method includes the further step of applying said transmit signal to a communication channel which includes a comb filter, said comb filter providing an output for each combined signal point; wherein in said selecting step each signal point of the sequence is selected in response to a respective subset of said input data; and wherein in said combining step said predetermined function is such as to enable recovery of each subset of input data from a respective one of the outputs of said comb filter independent of any of the other outputs of said comb filter.

Claim 23

The invention of claim 18 wherein the signal points of the base constellation are points of an underlying lattice which has a point at the origin and wherein the underlying lattice can be formed as the union of non-overlapping translates of the base constellation.

Claim 24

The invention of claim 13 comprising the further steps of applying said transmit signal to a communication channel, receiving said transmit signal from said communication channel, and processing the received transmit signal to recover said input data.

Claim 27

The invention of claim 21 wherein said transmit constellation and said expanded receiver constellation are other than M 2 -ary quadrature amplitude modulation constellations.

Claim 28

The invention of claim 21 wherein said input data is binary data, wherein each of said subsets is a binary word comprised of respective bits of said binary data, wherein each selected transmit constellation symbol is selected as a function of the value of the bits of the respective one of said binary words, and wherein said portion is at least one bit of the respective binary word.

Claim 29

The invention of claim 21 wherein said channel includes a comb filter, each different output of said comb filter corresponding to a different one of the symbols of said expanded receiver constellation.

Claim 30

The invention of claim 21 comprising the further step of recovering said input data from said sequence of receiver symbols.

Claim 33

The invention of claim 26 wherein said channel includes a comb filter, each different output of said comb filter corresponding to a different one of the symbols of said expanded receiver constellation.