Reverse link correlation filter in wireless communication systems
First Claim
1. A method for receiving signals over a code division multiple access (CDMA) channel, each received signal having a user-unique code and an associated despreading rate, the method comprising:
- correlating a received signal with the user-unique code at a basic despreading rate using time multiplexing in a single correlation filter to produce one or more sets of correlated outputs;
demultiplexing and demodulating the sets of correlated outputs; and
when the associated despreading rate is a multiple of the basic despreading rate, summing the demultiplexed and demodulated sets of correlated outputs at the multiple of the basic despreading rate to recover user information from the received signal at the associated despreading rate.
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Abstract
A single, common correlation filter (CF) core is provided in a receiver for recovery of data from received code division multiple access (CDMA) signals. Signals are received over CDMA channels with different data rates, where the received signals include user information such as pilot and data symbols that have been spread according to different despreading rates including tier 1, tier 2 and tier 3 rates, where tier 1 is the smallest despreading rate. The received signal is correlated at the smallest despreading rate in the correlation filter (CF) by time multiplexing delayed versions of the pseudorandom noise (PN) code. The correlated information is then demultiplexed and pilot-aided QPSK demodulated. The demodulated information is summed at the proper integer multiple of the tier 1 rate to achieve tier 2 and tier 3 despreading rates. According to an embodiment, the three strongest multipaths components in terms of the received power are selected in a window or time period for optimal information recovery.
36 Citations
26 Claims
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1. A method for receiving signals over a code division multiple access (CDMA) channel, each received signal having a user-unique code and an associated despreading rate, the method comprising:
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correlating a received signal with the user-unique code at a basic despreading rate using time multiplexing in a single correlation filter to produce one or more sets of correlated outputs;
demultiplexing and demodulating the sets of correlated outputs; and
when the associated despreading rate is a multiple of the basic despreading rate, summing the demultiplexed and demodulated sets of correlated outputs at the multiple of the basic despreading rate to recover user information from the received signal at the associated despreading rate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 23, 24)
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13. A receiver configured to receive signals over a code division multiple access (CDMA) channel, each received signal having a user-unique code and an associated despreading rate, comprising:
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a correlation filter configured to correlate a received signal with the user-unique code at a basic despreading rate using time multiplexing to produce one or more sets of correlated outputs;
a demultiplexer configured to demultiplex the sets of correlated outputs;
a data post processor configured to demodulate the sets of demultiplexed outputs; and
when the associated despreading rate is a multiple of the basic despreading rate, said data post processor configured to sum the demultiplexed and demodulated sets of correlated outputs at the multiple of the basic despreading rate to recover user information from the received signal at the associated despreading rate. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 25, 26)
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Specification