Intersymbol interference channel coding scheme
First Claim
1. A method for transmitting data over an intersymbol interference channel using a predetermined signalspace code, the method comprising the steps of:
 receiving a sequence of input signal points (408) selected from a predetermined constellation of signal points; and
adding a dither signal to each of the input signal points, the dither signal (406) applied to a present signal point being selected as a function of previous signal points in the sequence and the current state of a finitestate machine (400) used to generate the signalspace code.
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Abstract
Intersymbol interference and precoding loss are minimized by combining the precoding and coding operations. An intersymbol interference coder uses a feedback loop to apply a dither sequence to a sequence of input signal points. The dither signal applied to each input signal point is a function of the previous signal points in the sequence. The intersymbol interference coder implements, for example, a trellis coding operation by selecting one of several different modulo operations to determine the magnitude of the dither signal, the selection being made in response to the current trellis state. The sequence of signal points output from the intersymbol interference coder generates a valid sequence of the trellis code input to the Viterbi decoder.
49 Citations
17 Claims

1. A method for transmitting data over an intersymbol interference channel using a predetermined signalspace code, the method comprising the steps of:

receiving a sequence of input signal points (408) selected from a predetermined constellation of signal points; and adding a dither signal to each of the input signal points, the dither signal (406) applied to a present signal point being selected as a function of previous signal points in the sequence and the current state of a finitestate machine (400) used to generate the signalspace code.  View Dependent Claims (2, 3, 4, 5)


6. A method for transmitting data over an intersymbol interference channel, the method comprising the steps of:

partitioning a constellation of signal points into a first group of subsets; partitioning each of the subsets in the first group of subsets into at least two subsets; generating a sequence of input signal points (102) selected from the constellation; and adding a dither signal (406) to each of the input signal points, the dither signal applied to a present signal point being a point within a Voronoi region of a subset in the first group of subsets and being a function of a previous signal point in the sequence.


7. Data transmission apparatus for transmitting data using a predetermined signalspace code, comprising:

means for selecting a sequence of input signal points (102) from a predetermined constellation of signal points; and means for adding a dither signal (104) to each of the input signal points, including means for selecting the dither signal applied to a present signal point as a function of the previous signal points in the sequence and the current state of a finitestate machine (400) used to generate the signalspace code.  View Dependent Claims (8, 9, 10, 11)


12. A method for transmitting data over an intersymbol interference channel using a predetermined signalspace code, the method comprising the steps of:

receiving a stream of input data (102); and generating a sequence of coded signal points (406,
410) of the signalspace code, the current point of the signal space code is a function of selected data from said stream of input data and the current output of a finitestate machine,wherein the current input to the finitestate machine is derived from a previously generated signal point of the signalspace code.  View Dependent Claims (13)


14. Apparatus for transmitting data over an intersymbol interference channel using a predetermined signalspace code, comprising:

means for receiving a stream of input data (102); a finitestate machine (400) having a current input and generating a current output; and means for generating a sequence of coded signal points (406) of the signalspace code, the current point of the signalspace code is a function of selected data from said stream of input data and the current output of a finitestate machine (400), wherein the current input to the finitestate machine is derived from a previously generated signal point of the signalspace code.  View Dependent Claims (15)


16. A method for transmitting data over an intersymbol interference channel to a receiver using a predetermined signalspace code, the method comprising the steps of:

receiving a stream of input signal points (102); and modifying a current input signal point value (104) to generate at an input to a Viterbi decoder in said receiver a current sample of a sequence of the signalspace code, said modifying being performed as a function of a current output of a finitestate machine, the finitestate machine receiving as a current input the previous sample of said sequence of the signalspace code.


17. A method for transmitting data over an intersymbol interference channel using a predetermined trellis code based on partitioning a lattice, the method comprising the steps of:

receiving a sequence of input signal points (408) selected from a predetermined constellation of signal points; and adding a dither signal (408) to each of the input signal points, the dither signal applied to a present signal point being selected as a function of previous signal points in the sequence and being a point within a Voronoi region of a sublattice in a first level of lattice partitioning used to generate the trellis code.

1 Specification