Point-to multipoint digital communications system facilitating use of a reduced complexity receiver at each of the multipoint sites

• US 5,912,920 A
• Filed: 03/27/1997
• Issued: 06/15/1999
• Est. Priority Date: 03/27/1997
• Status: Expired due to Term

• Current Assignee: Tellabs Operations Incorporated (Infinera Corp.)
• Original Assignee: Tellabs Operations Incorporated (Infinera Corp.)
• Inventors: Marchok, Daniel J., Kapoor, Samir
• Primary Examiner(s): TSE, YOUNG TOI
• Application Number:
  US08/824,923
• Time in Patent Office: 810 Days
• Field of Search: 375/219, 375/221, 375/257, 375/259, 375/261, 375/271, 375/279, 370/336, 370/389, 370/442, 370/458, 370/498
• US Class Current: 375/219
• CPC Class Codes: H04L 2001/0093 Point-to-multipoint
• CPC Class Codes: H04L 25/03057 with a recursive structure H04L25/03031 takes precedence
• CPC Class Codes: H04L 27/38 Demodulator circuits; Receiver circuits

Abstract

A communications system is set forth comprising a plurality of remote receivers numbering M for receiving and demodulating respective PSK symbols received from a transmission medium. A central transmitter transmits periodically occurring frames of data to the plurality of receivers over the transmission medium. Each frame of data contains L total symbols including a subset of X_m symbols designated for each one of the M plurality of remote receivers. The transmitter interleaves the X_m symbols in a given frame into a plurality of periodic, non-consecutive groups of R symbols per group, wherein R<X_m. In accordance with one embodiment of the invention, each of the remote receivers includes an equalizer implemented as a digital filter having N taps. In such instances, the transmitter interleaves the X_m symbols in a given frame into a plurality of periodic, non-consecutive groups of R symbols per group, wherein R≦N.

Claims

1. A communications system comprising:

a plurality of remote receivers numbering M for receiving and demodulating respective PSK symbols received from a transmission medium;

a central transmitter transmitting periodically occurring frames of data to the plurality of receivers over the transmission medium, each frame of data having a header defining each frame, each frame of data containing L total symbols including a subset of X_m symbols respectively designated for each one of the M plurality of remote receivers, the transmitter interleaving the X_m symbols for a given remote receiver in a given frame into a plurality of periodic, non-consecutive groups of R symbols per group, wherein R<

X_m.

2. A communications system as claimed in claim 1 wherein X_m =int(L/M).

3. A communications system as claimed in claim 1 wherein the transmission medium is air.

4. A communications system as claimed in claim 1 wherein the transmission medium is a transmission line.

5. A communications system as claimed in claim 4 wherein the transmission medium is coaxial cable.

6. A communications system as claimed in claim 1 wherein X_m= 128 symbols and R≦

64 symbols.

7. A communications system as claimed in claim 1 wherein R≦

32.

8. A communications system as claimed in claim 1 wherein R≦

16.

9. A communications system as claimed in claim 1 wherein R≦

2.

10. A communications system as claimed in claim 1 wherein R=1.

11. A communications system comprising:

a plurality of remote receivers numbering M for receiving and demodulating respective PSK symbols received from a transmission medium;

a transmitter transmitting periodically occurring frames of data to the plurality of receivers through the transmission medium, each frame of data containing L total symbols with a subset of X_m symbols designated respectively for each one of the M plurality of remote receivers, the transmitter interleaving the X_m symbols for a given receiver in a given frame into a plurality of periodic, non-consecutive groups of R symbols per group, wherein R<

X_m, the X_m symbols being the number of symbols over which each one of the plurality of receivers conducts a single error checking routine.

12. A communications system as claimed in claim 11 wherein X_m =int(L/M).

13. A communications system as claimed in claim 11 wherein the transmission medium is air.

14. A communications system as claimed in claim 11 wherein the transmission medium is a transmission line.

15. A communications system as claimed in claim 14 wherein the transmission medium is coaxial cable.

16. A communications system as claimed in claim 11 wherein X_m =128 symbols and R≦

64 symbols.

17. A communications system as claimed in claim 11 wherein R≦

32.

18. A communications system as claimed in claim 11 wherein R≦

16.

19. A communications system as claimed in claim 11 wherein R≦

2.

20. A communications system as claimed in claim 11 wherein R=1.

21. A communications system comprising:

a plurality of remote receivers numbering M for receiving and demodulating respective PSK symbols received from a transmission medium, each of the plurality of receivers comprising a digital equalization filter having N taps;

a transmitter transmitting periodically occurring frames of data to the plurality of receivers through the transmission medium, each frame of data containing L total symbols with a subset of X_m symbols respectively designated for each one of the M plurality of remote receivers, the transmitter interleaving the X_m symbols for a given receiver in a given frame into a plurality of periodic, non-consecutive groups of R symbols per group, wherein R≦

N.

22. A communications system as claimed in claim 21 wherein X_m =int(L/M).

23. A communications system as claimed in claim 21 wherein the transmission medium is air.

24. A communications system as claimed in claim 21 wherein the transmission medium is a transmission line.

25. A communications system as claimed in claim 24 wherein the transmission medium is coaxial cable.

26. A communications system as claimed in claim 21 wherein X_m =128 symbols and R≦

64 symbols.

27. A communications system as claimed in claim 21 wherein R≦

32.

28. A communications system as claimed in claim 21 wherein R≦

16.

29. A communications system as claimed in claim 21 wherein R≦

2.

30. A communications system as claimed in claim 21 wherein R=1.