CDMA system with frequency domain equalization
First Claim
1. A code division multiple access (CDMA) system comprising:
- at least one CDMA transmitter having;
at least one spreader for spreading a packet having one or more blocks to derive an M×
G spread sequence for each of said blocks to thereby form a spread signal, where M represents number of symbols, said number being greater or equal to one, each of said at least one spreader having a processing gain of G;
anda sequence extender for extending each of said blocks using a predetermined number of chips to thereby form an extended spread signal, said sequence extender having an extender input coupled to said spreader output.
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Accused Products
Abstract
A code division multiple access (CDMA) system and methods for processing symbol blocks of a spread signal in both frequency and time domains are described. A transmitter (10) of the CDMA system spreads pilot symbols and data of the symbol blocks to derive a spread sequence. Thereafter, the spread sequence is extended with a predetermined number of chips and pulse shaped for transmission as the spread signal. A receiver (400) of the CDMA system receives the spread signal, removes the predetermined number of chips and then orthogonally transforms the spread signal to the frequency domain to derive a transformed signal. The transformed signal is equalized in the frequency domain to derive an equalized signal. The equalized signal is then inverse orthogonally transformed to an output in the time domain. The output is then despreaded to derive the symbol blocks.
138 Citations
45 Claims
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1. A code division multiple access (CDMA) system comprising:
at least one CDMA transmitter having; at least one spreader for spreading a packet having one or more blocks to derive an M×
G spread sequence for each of said blocks to thereby form a spread signal, where M represents number of symbols, said number being greater or equal to one, each of said at least one spreader having a processing gain of G;and a sequence extender for extending each of said blocks using a predetermined number of chips to thereby form an extended spread signal, said sequence extender having an extender input coupled to said spreader output. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method for transmitting signals in a code division multiple access (CDMA) system, said method comprising the steps of:
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spreading, by at least one spreader, a packet having one or more blocks to derive an M×
G spread sequence for each of said blocks to thereby form a spread signal, where M represents number of symbols, said number being greater or equal to one, each of said at least one spreader having a processing gain of G;and extending, by a sequence extender, said M×
G spread sequence using a predetermined number of chips to thereby form an extended spread signal, said M×
G spread sequence being received from a spreader output of each of said at least one spreader. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. A code division multiple access (CDMA) system comprising:
at least one CDMA receiver for processing a received signal, said CDMA receiver having; a sequence extension remover for removing a predetermined number of chips from at least one predetermined position of said received signal to thereby form a modified signal; an orthogonal transform block, coupled to said sequence extension remover, for transforming said modified signal in a first domain to form a transformed signal in a second domain; an equalizer block, coupled to said transform block and having a channel estimator, for equalizing said transformed signal to thereby reduce channel distortion and form an equalized signal; an inverse orthogonal transform block, coupled to said equalizer block, for inverse transforming said equalized signal to form an output in said first domain; and a despreader for despreading said output to thereby derive a group of symbols. - View Dependent Claims (30, 31, 32, 33, 34, 35, 36, 37, 38)
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39. A method for processing a received signal received in a code division multiple access (CDMA) system, said method comprising the steps of:
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removing a predetermined number of chips from at least one predetermined position of said received signal to thereby form a modified signal; orthogonally transforming said modified signal in a first domain to form a transformed signal in a second domain; equalizing said transformed signal to thereby reduce channel distortion and form an equalized signal; inverse orthogonally transforming said equalized signal to form an output in said first domain; and despreading said output to thereby derive a group of symbols. - View Dependent Claims (40, 41, 42, 43, 44, 45)
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Specification