Patent ID: 8014456
Filing Date: 2011-09-06
Classification: H04L

Abstract:
1. A system comprising: a differential demodulation module that (i) receives modulated signals from R antennas and (ii) differentially demodulates said modulated signals to generate differentially demodulated signals, where R is an integer greater than 1: a first summing module that sums said differentially demodulated signals to generate a combined signal; a state detection module that detects states of X symbols in said combined signal, where X is an integer greater than 1, and where each of said X symbols has one of a first state and a second state; and a second summing module that (i) receives Y preamble sequences each comprising X predetermined symbols and (ii) generates X sums for each of said Y preamble sequences by adding each of said states of said X symbols with corresponding states of said X predetermined symbols of each of Y preamble sequences, where Y is an integer greater than 1, wherein said states of said X predetermined symbols are generated by inverting states of derived symbols in derived preamble sequences, wherein said derived preamble sequences are derived from said Y preamble sequences, wherein each of said Y preamble sequences is different from others of said Y preamble sequences, and wherein each of said derived symbols of one of said derived preamble sequences has a first binary value when a corresponding symbol and a symbol adjacent to said corresponding symbol in a corresponding one of said Y preamble sequences have opposite binary values, and said each of said derived symbols has a second binary value that is opposite to said first binary value when said corresponding symbol and said symbol adjacent to said corresponding symbol have the same binary value.