Interference signal cancellation system
First Claim
1. An interference signal cancellation system, comprising:
- a CDMA demodulator disposed for each of a plurality of diffusion codes and having a matched filter and an identifier;
a likelihood calculator for each of said CDMA demodulators;
a first buffer for storing provisional decision values;
a second buffer for storing likelihoods;
an order determining device for determining an order according to the likelihoods stored in said second buffer;
a respreading device for performing respreading according to the order determined by said order determining device; and
a delay device for delaying a received signal; and
a subtractor for subtracting a result of the respreading from data of the signal delayed by said delay device;
wherein interference is canceled while demodulating codes in decreasing order of likelihood.
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Accused Products
Abstract
The interference signal cancellation system of the invention has: usual CDMA demodulators respectively disposed for codes, each of the CDMA demodulators having a matched filter 105 and an identifier 107; and a likelihood calculator 108 for each of the demodulators. The apparatus further has: a buffer 103 which stores provisional decision values; another buffer 109 which stores likelihoods; an order determining device 110 which determines an order in accordance with the likelihoods; a respreading device 111 which performs respreading in accordance with the determined order; a delay device 102 which delays a received signal; and a subtractor 112 which subtracts a result of the respreading from the delayed data. For each symbol, the largest likelihood is selected, and a replica is generated by using it. A desired performance is attained by performing one provisional decision and one demodulation. Therefore, computational complexity is reduced and realization is facilitated.
80 Citations
6 Claims
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1. An interference signal cancellation system, comprising:
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a CDMA demodulator disposed for each of a plurality of diffusion codes and having a matched filter and an identifier; a likelihood calculator for each of said CDMA demodulators; a first buffer for storing provisional decision values; a second buffer for storing likelihoods; an order determining device for determining an order according to the likelihoods stored in said second buffer; a respreading device for performing respreading according to the order determined by said order determining device; and a delay device for delaying a received signal; and a subtractor for subtracting a result of the respreading from data of the signal delayed by said delay device; wherein interference is canceled while demodulating codes in decreasing order of likelihood. - View Dependent Claims (2, 3, 4, 5, 6)
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Specification