Pulse or digital communications – Spread spectrum – Direct sequence
Reexamination Certificate
2008-01-22
2008-01-22
Tse, Young T. (Department: 2611)
Pulse or digital communications
Spread spectrum
Direct sequence
C375S260000, C370S209000, C370S335000
Reexamination Certificate
active
10218456
ABSTRACT:
In signal detection system and method implemented to reduce the effects of interference in multi-user detection systems, a receiver defines a frame of symbols containing at least one window based upon a number of user signals contained in a received signal r(t). A symbol amplitude of a single-user in the multi-user system is approximated over the window of the frame based on a number of reflected signal paths of the received user signal. A perturbative correction value is calculated based upon a correlation matrix. An estimation of the symbol amplitude of the single-user signal is calculated over one or a number of windows of the frame. The single-user signal is detected when the symbol amplitudes of the entire signal within the frame has been calculated. To reduce the number of interfering users in a multicell CDMA system, the symbol codes are modified to include an even code and an odd code. The even and odd codes are symmetrically separated over the duration of the symbol to form an interference reduction window. If the delay offsets of the symbol codes are less than the interference reduction window and the even codes are assigned to a first cell, and odd codes to adjacent cells, then the adjacent cell interference vanishes.
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Akin Gump Strauss Hauer & Feld & LLP
Industrial Technology Research Institute
Tse Young T.
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