Hybrid line coding method and apparatus using 4B/3T encoding for payload bits and 1B/1T encoding for framing information
AssigneeAlcatel Network Systems, Inc.
InventorDale L. Krisher
Life of this patent
Estimating the term…
Abstract
Existing infrastructures such as DS1 or E1 are used at currently accepted rates to carry a third more information by using a hybrid encoding technique wherein a 4B3T encoding is done for the payload bits, while a 1B1T encoding technique is used for framing information. In this way, for example, a DS1 can be used at 1.54 Mbit per second to carry 2.058 Mbits of binary payload, while respecting the 8 kilobits of framing expected by DS1 hardware. Similarly, for example, an E1 infrastructure can be used at the accepted 2.048 Mbit per second rate to carry 2.560 Mbits of binary payload plus 128 kilobits of binary framing/CRC without having to change the accepted E1 framing techniques.
Claims19
A method, comprising the steps of:
- (a) determining a next data bit and current disparity value signal to be coded is either (i) a binary framing bit and next executing a step (b) or (ii) a binary payload bit and next executing a step (c):
- (b) converting the next binary framing bit and the current disparity value signal to a ternary framing symbol using a first encoding method;
- (c) converting the next binary payload bit and the current disparity value signal to a ternary payload symbol using a second encoding method, providing an updated disparity value signal and repeating step (a).
Apparatus for providing a ternary payload plus framing datastream signal, comprising:
- a ternary multiplexer, responsive to a ternary framing datastream signal and to a ternary payload datastream signal, for providing the ternary payload plus framing datastream signal;
- a framing encoder, responsive to a binary framing datastream signal, for providing the ternary framing datastream signal;
- and
- a data encoder, responsive to a binary payload datastream signal, for providing the ternary payload datastream signal.
A binary bit to ternary symbol encoding method, comprising the steps of:
- receiving (81f) a binary framing bit and current disparity value signal;
- converting (81g) the binary framing bit to a ternary framing symbol based on the binary framing bit and the current disparity value signal according to a first encoding method;
- providing (81h) the ternary framing symbol;
- and
- updating (81e) the current disparity value signal
- wherein the foregoing steps are performed in a repetitive manner exclusively on framing bits whereby payload bits are encoded separately according to a second encoding method for combination with framing bits encoded according to said foregoing steps.
Apparatus for communicating bidirectional signal information over a pair (12;
- 32) of twisted wire pairs each for carrying a first selected number (192;
- 240) of binary payload bits encoded as said first selected number of ternary payload symbols per frame at a selected symbol rate (1.544 Msymbols/second;
- 2.048 Msymbols/second), comprising:
- a first hybrid line coder/decoder (20a;
- 42a), responsive to a first binary payload datastream signal (54a;
- 82a) having an increased number (256;
- 320) of binary payload bits increased over said first selected number per frame and responsive to a first framing information signal, for providing a first ternary payload plus framing signal (74a;
- 32c) with said increased number (256;
- 320) of binary payload bits per frame encoded as said first selected number (192;
- 240) of ternary payload symbols per frame at said selected symbol rate, the first hybrid line coder/decoder (20a;
- 42a) also responsive to a second ternary payload plus framing signal (74b;
- 32b) having the increased number (256;
- 320) of binary payload bits per frame encoded as said first selected number (192;
- 240) of ternary payload symbols at said selected symbol rate, for providing a decoded second binary payload datastream signal (54b;
- 82b);
- and
- a second hybrid line coder/decoder (20b;
- 42b), responsive to a third binary payload datastream signal (54bb;
- 46d) for providing the second ternary payload plus framing signal (74b;
- 32b) with said increased number (256;
- 320) of binary payload bits per frame encoded as said first selected number (192;
- 240) of ternary payload symbols per frame at said selected symbol rate, the second hybrid line coder/decoder also responsive to the first ternary payload plus framing signal (74a;
- 32c) for providing a fourth binary payload datastream signal (54ab;
- 46c).
Dependencies are inferred from the claim text.