Method and apparatus for CDMA demodulation
AssigneeTexas Instruments Incorporated
InventorsJohn G. McDonough, Jane Wang
Life of this patent
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Abstract
A CDMA receiver (500) minimizes the use of hardware by taking advantage of the fact that Walsh sequences of a predetermined length (e.g., 16) are comprised of inverted and non-inverted versions of smaller length (e.g., 4) sequences. The receiver (500) performs the necessary uncovering operations for example of a Walsh sequence of length 16 by performing uncovering operations using smaller length Walsh sequences such as of length 4 and then performing subsequent summing operations with inverted and non-inverted versions of the results of such uncovering operations.
Claims10
A code division multiple access (CDMA) receiver, comprising:
- an input for reciving an information sequence covered by a Walsh sequence of length N;
- and
- uncovering circuit coupled to the input for uncovering the information sequence using a Walsh code, WMO, where M is less than 2log2(N)-1 and having a length N/M when the Walsh length, N, is even, and using a Walsh code, WM1, where M is less than pb 2log2(N)-1 and having a length N/M when the Walsh length, N, is odd.
A method for code division multiple access (CDMA) demdodulation, comprising the steps of:
- receiving an information sequence covered by a Walsh sequence of length N;
- and
- uncovering the information sequence using a Walsh code, WMO, where M is less than 2log2(N)-l and having a length N/M when the original Walsh length, N, is even, and using a Walsh code, WMl, where M is less than 2log2(N)-l and having a length N/M when the original Walsh length, N, is odd.
Dependencies are inferred from the claim text.