Data Communication
AssigneeSupergold Communication Limited
InventorTimothy O'Farrell
Life of this patent
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Abstract
A method and apparatus for data communication in a variety of communication systems using spread spectrum techniques and multilevel sequences in which distinct multilevel sequences used contain binary subsequences that interfere constructively such that synchronous cross-correlation values add constructively. By adding two subsequences from different sets it is ensured that neither subsequence belongs to the same set this in combination with use of correlators reducing complexity, and facilitates increasing the order of a modulation scheme thus enhancing the bandwidth efficiency.
Claims25
A method for data communication using spread spectrum techniques and multilevel sequences characterised in that selection distinct multilevel sequences used in the method contain binary subsequences that interfere constructively such that synchronous cross-correlation values add constructivly.
A method as claimed in any preceding claim in which a lookup table is used to decode data bits corresponding to a detected multilevel sequence.
A method as claimed in any preceding claim wherein the multilevel sequences are constructed by adding together subsequences taken from complementary sets of binary sequences.
A method as claimed in any preceding claim including the step of identifying sequences having the properties of being cyclically distinct and possessing:
- low autocorrelation sidelobes;
- low intra-crosscorrelation magnitudes;
- and
- low inter-crosscorrelation magnitudes.
A data communications apparatus using spread spectrum techniques and multilevel sequences characterised in that the apparatus incorporates means for selection of distinct multilevel sequences containing constructively interfereing binary subsequences such that synchronous cross-correlation values add constructivly.
A data communications apparatus incorporating means for isolating a correlator output having a greatest peak from the bank of n correlators corresponding to the set from which the subsequence was taken.
Dependencies are inferred from the claim text.