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A novel robust communications scheme whereby a repetition code at the transmitter and an associated cumulative decoder at the receiver are used to increase the reliability of transmission in a communications system. The robust communications scheme of the present invention is effective to increase t

A novel robust communications scheme whereby a repetition code at the transmitter and an associated cumulative decoder at the receiver are used to increase the reliability of transmission in a communications system. The robust communications scheme of the present invention is effective to increase the reliability of transmission by repetitively transmitting each data segment a number of times in accordance with a repetition code and subsequently collecting the received energy at the receiver over an accordingly longer period of time. Accumulating the received energy over a longer period of time at the receiver, yields a marked improvement in the signal to noise ratio (SNR) of the receiver.

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1. A method of cumulatively decoding input metrics corresponding to a demodulated received signal transmitted as a sequence of segments wherein a segment at a transmitter is repeated a predetermined number of times, said method comprising the steps of:summing said input metrics with weighted metrics

1. A method of cumulatively decoding input metrics corresponding to a demodulated received signal transmitted as a sequence of segments wherein a segment at a transmitter is repeated a predetermined number of times, said method comprising the steps of:summing said input metrics with weighted metrics for each repeated segment so as to generate a single set of cumulative metrics therefrom;applying a hard decision algorithm to said cumulative metrics and generating hard decisions and updated metrics associated with said hard decisions in response thereto;accumulating said updated metrics associated with said hard decisions over a plurality of segments and applying a weighting function so as to generate said weighted metrics therefrom; andrepeating said steps of summing, applying and accumulating for each repeated segment. 2. The method according to claim 1, further comprising the step of providing a soft decision decoder adapted to generate output data from said hard decisions and said updated metrics. 3. The method according to claim 1, wherein said sequence of segments comprises a sequence of codewords. 4. The method according to claim 1, wherein said sequence of segments comprises a sequence of symbols. 5. The method according to claim 1, wherein said sequence of segments comprises a sequence of bits. 6. The method according to claim 1, wherein said updated metrics associated with said hard decisions comprise spread spectrum correlator values. 7. The method according to claim 1, wherein each codeword at the transmitter is transmitted four times and wherein output data is generated after the accumulation of input metrics over a four codeword period. 8. The method according to claim 1, wherein said steps of summing, applying and accumulating are repeated four times. 9. The method according to claim 1, wherein said method is implemented in an Application Specific Integrated Circuit (ASIC). 10. The method according to claim 1, wherein said method is implemented in a Field Programmable Gale Array (FPGA). 11. A cumulative decoder for decoding input metrics corresponding to a demodulated received signal transmitted as a sequence of segments wherein a segment at a transmitter is repeated a predetermined number of times, comprising:summing means adapted to sum said input metrics with cumulative metrics for each repeated segment generating a single set of summed metrics therefrom;search means for applying a hard decision algorithm to said summed metrics and generating hard decisions and updated metrics associated with said hard decisions in response thereto;accumulating means for accumulating said updated metrics generated by said search means over each repeated segment so as to generate said cumulative metrics therefrom; andwherein said updated metrics are generated and accumulated over said predetermined number of segments. 12. The decoder according to claim 11, further comprising weighting means adapted to apply a weighting function to said cumulative metrics before summation by said summing means. 13. The decoder according to claim 11, wherein said search means comprises means for performing a maximum search. 14. The decoder according to claim 11, wherein said search means comprises means for performing a search for a first maximum and a second maximum. 15. The decoder according to claim 11, further comprising a soft decision decoder adapted to generate output data from said hard decisions and said cumulative metrics. 16. The decoder according to claim 11, wherein said sequence of segments comprises a sequence of codewords. 17. The decoder according to claim 11, wherein said sequence of segments comprises a sequence of symbols. 18. The decoder according to claim 11, wherein said sequence of segments comprises a sequence of bits. 19. The decoder according to claim 11, wherein said input metrics comprise spread spectrum correlator values. 20. The decoder according to claim 11, wherein said accumulating means comprises means for stori ng a normalized average of said cumulative metrics. 21. The decoder according to claim 11 adapted to be implemented in an Application Specific Integrated Circuit (ASIC). 22. The decoder according to claim 11 adapted to be implemented in a Field Programmable Gate Array (FPGA). 23. A cumulative decoder for decoding input correlation values corresponding to a demodulated received signal transmitted as a sequence of codewords wherein a codeword at a transmitter is repeated one or more times, comprising:summing means adapted to sum said input correlation values with cumulative correlation values for each repeated codeword so as to yield a single set of summed correlation values therefrom;search means adapted to perform a maximum search on said summed correlation values and to generate one or more maximum values corresponding to hard decisions and updated correlation values in response thereto;accumulating means for accumulating said updated correlation values generated by said search means over a plurality of codewords so as to generate said cumulative correlation values therefrom; andwherein for each output codeword, said cumulative correlation values are accumulated over all repeated codewords. 24. The decoder according to claim 23, further comprising means for applying a weighting function to said cumulative correlation values before summation by said summer. 25. The decoder according to claim 23, wherein said accumulating means comprises correlation memory adapted to maintain and store a normalized average of said updated correlation values. 26. The decoder according to claim 23, wherein said search means comprises means for performing a search for a first maximum and a second maximum. 27. The decoder according to claim 23, further comprising a soft decision decoder adapted to generate output data from said hard decisions and said cumulative correlation values associated therewith. 28. The decoder according to claim 23 adapted to be implemented in an Application Specific Integrated Circuit (ASIC). 29. The decoder according to claim 23 adapted to be implemented in a Field Programmable Gate Array (FPGA). 30. A method of cumulative decoding input correlation values corresponding to a demodulated received signal transmitted as a sequence of codewords wherein a codeword at a transmitter is repeated one or more times, comprising:summing said input correlation values with cumulative correlation values for each repeated codeword so as to yield a single set of summed correlation values therefrom;performing a maximum search on said summed correlation values and generating one or more maximum values corresponding to hard decisions and updated correlation values in response thereto;accumulating said updated correlation values generated by said search means over each repeated codeword so as to generate said cumulative correlation values therefrom; andwherein for each output codeword, said cumulative correlation values are accumulated over all repeated codewords. 31. The method according to claim 30, further comprising the step of applying a weighting function to said cumulative correlation values before summation by said summer. 32. The method according to claim 30, wherein said step of accumulating comprises maintaining and storing a normalized average of said updated correlation values. 33. The method according to claim 30, wherein said step of performing a maximum search comprises searching for a first maximum and a second maximum. 34. The method according to claim 30, further comprising the step of providing a soft decision decoder adapted to generate output data from said hard decisions and said cumulative correlation values. 35. The method according to claim 30, wherein said method is implemented in an Application Specific Integrated Circuit (ASIC). 36. The method according to claim 30, wherein said method is implemented in a Field Programmable Gate Array (FPGA). 37. A method of robust communications in a shared communications media b ased network wherein original transmit data is encoded and repetitively transmitted N times to form N sub-transmissions, said method comprising the steps of:generating a demodulated signal from a signal received over said network;decoding and generating updated metrics for each of said N sub-transmissions within said demodulated signal, and accumulating said updated metrics to generate a single set of cumulative metrics, thereby accumulating energy in the received signal over a period of time N times longer than said original transmit data;performing soft decision decoding on said cumulative metrics so as to generate output data therefrom; andwherein N is a positive integer. 38. The method according to claim 37, wherein N equals 4. 39. The method according to claim 37, wherein said original transmit data comprises a plurality of codewords whereby each codeword is transmitted N times. 40. The method according to claim 37, wherein said original transmit data comprises a plurality of symbols whereby each symbol is transmitted N times. 41. The method according to claim 37, wherein said original transmit data comprises a plurality of bits whereby each bit is transmitted N times. 42. The method according to claim 37, wherein said method is implemented in an Application Specific Integrated Circuit (ASIC). 43. The method according to claim 37, wherein said method is implemented in a Field Programmable Gate Array (FPGA). 44. A modem transceiver for transmitting and receiving signals in a shared communications media based network, comprising:a coupling circuit for generating a receive signal received over said network and for outputting a transmit signal onto said network;a transmitter adapted to modulate data to be transmitted in accordance with a modulation scheme so as to generate a transmit waveform therefrom, said transmitter comprising a segment repeater adapted to repeatedly transmit each input segment a predetermined number of times;a receiver to demodulate said receive signal in accordance with said modulation scheme so as to generate a receive data signal therefrom, said receiver comprising a cumulative decoder for decoding input metrics corresponding to a demodulated received signal transmitted as a sequence of segments wherein a segment at a corresponding transmitter is repeated one or more times, said cumulative decoder comprising:summing means adapted to sum said input metrics with cumulative metrics for each repeated segment to yield a single set of summed metrics therefrom;search means for applying a hard decision algorithm to said summed metrics and generating hard decisions and updated metrics associated with said hard decisions in response thereto;accumulating means for accumulating said updated metrics generated by said search means for each repeated segment so as to generate said cumulative metrics therefrom;wherein for each output segment generated, updated metrics are generated and accumulated all repeated segments;a media access control (MAC) circuit adapted to interface an application processor to said shared communications media; andsaid application processor adapted to control the operation of said transmitter, receiver and MAC and to provide an interface between said MAC and an external host. 45. The modem according to claim 44, wherein said modulation scheme comprises code shift keying (CSK) modulation. 46. The modem according to claim 44, wherein said receiver further comprises weighting means adapted to apply a weighting function to said cumulative metrics before summation by said summing means. 47. The modem according to claim 44, wherein said sequence of segments comprises a sequence of codewords. 48. The modem according to claim 44, wherein said sequence of segments comprises a sequence of symbols. 49. The modem according to claim 44, wherein said sequence of segments comprises a sequence of bits. 50. The modem according to claim 44, wherein said hard decision metrics comprise spread spectrum correlator values. 51. The modem according to claim 44, further comprising a soft decision decoder adapted to generate output data from said hard decisions and said cumulative metrics. 52. The modem according to claim 44 adapted to be implemented in an Application Specific Integrated Circuit (ASIC). 53. The modem according to claim 44 adapted to be implemented in a Field Programmable Gate Array (FPGA).