Common data path rake receiver for a CDMA demodulator circuit
First Claim
1. A demodulator for demodulating a spread spectrum signal transmitted over a physical channel and received with multiple instances corresponding to plural propagation paths, comprising:
- a demodulating data path operable to perform spread spectrum demodulating operations by performing de-scrambling and de-spreading operations to produce recovered symbols and performing de-rotating operation on the recovered symbols; and
a control system operable to manage time-shared access to the demodulating data path for performing spread spectrum demodulating operations on each of the instances of the spread spectrum signal in a time divided manner such that the control system grants a first time-shared access to the demodulating data path to perform de-scrambling and de-spreading and grants a second time-shared access to the demodulating data path to perform de-rotating.
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Accused Products
Abstract
An architecture for a rake receiver of a CMDA demodulator utilizes a common data path for signal processing. This common data path is shared by all channels (either physical channels or propagation paths within physical channels) to avoid redundant calculations, reduce circuit space and reduce power consumption. The sharing of the common data path for demodulation is made on a time divided manner, with each channel being given sequential access to the data path to perform all or part of a given demodulation function (for example, de-scrambling, de-spreading, de-rotating, and de-skewing accumulation).
16 Citations
22 Claims
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1. A demodulator for demodulating a spread spectrum signal transmitted over a physical channel and received with multiple instances corresponding to plural propagation paths, comprising:
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a demodulating data path operable to perform spread spectrum demodulating operations by performing de-scrambling and de-spreading operations to produce recovered symbols and performing de-rotating operation on the recovered symbols; and a control system operable to manage time-shared access to the demodulating data path for performing spread spectrum demodulating operations on each of the instances of the spread spectrum signal in a time divided manner such that the control system grants a first time-shared access to the demodulating data path to perform de-scrambling and de-spreading and grants a second time-shared access to the demodulating data path to perform de-rotating. - View Dependent Claims (2, 3, 4, 5)
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6. A demodulator for demodulating spread spectrum signals transmitted over a plurality of channels, comprising:
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a demodulating data path operable to perform spread spectrum de-scrambling/de-spreading, de-rotating and accumulating operations, wherein the demodulating data path is a shared processing resource with respect to performing operations as to all received multi-path signals of the plurality of channels; and a control system operable to manage time-shared access to the demodulating data path shared processing resource for performing spread spectrum demodulating operations on each of the plurality of channels, and multi-path signals therein, in a time divided manner such that de-scrambling/de-spreading operations are performed in a first time divided period and de-rotating operations are performed in a second time divided period. - View Dependent Claims (7, 8, 9)
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10. A method for demodulating a spread spectrum signal transmitted over a physical channel and received with multiple instances corresponding to plural propagation paths, comprising the steps of:
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performing spread spectrum de-scrambling and de-spreading demodulating operations on the received spread spectrum signal to produce recovered symbols and performing de-rotating operation on the recovered symbols along a single demodulating data path; and managing time-shared access to the demodulating data path for performing spread spectrum demodulating operations on each of the instances of the spread spectrum signal in a time divided manner such that a first time-shared access is granted to the demodulating data path to perform de-scrambling and de-spreading and a second time-shared access is granted to the demodulating data path to perform de-rotating. - View Dependent Claims (11, 12, 13)
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14. A method demodulating spread spectrum signals transmitted over a plurality of channels, comprising:
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performing spread spectrum de-scrambling/de-spreading, de-rotating and accumulating operations on the received spread spectrum signals along a single demodulating data path, wherein the demodulating data path is a shared processing resource with respect to performing operations as to all received multi-path signals of the plurality of channels; and managing time-shared access to the demodulating data path shared processing resource for performing spread spectrum demodulating operations on each of the plurality of channels, and multi-path signals therein, in a time divided manner such that de-scrambling/de-spreading operations are performed in a first time divided period and de-rotating operations are performed in a second time divided period. - View Dependent Claims (15, 16)
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17. A demodulator for spread spectrum signals, comprising:
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a shared access data path, comprising; a symbol integration stage operable to perform de-scrambling and de-spreading operations on the spread spectrum signals to produce recovered symbols; and a symbol combining stage operable to perform de-rotation on the recovered symbols and to accumulate de-rotated symbols and produce a output symbol; and a control circuit selectively granting each spread spectrum signal time divided access to the shared access data path for the purpose of utilizing an appropriate one of the symbol integration stage and the symbol combining stage to operate on the spread spectrum signals, wherein the control circuit grants a first time divided access to the symbol integration stage with respect to a certain spread spectrum signal to de-scramble and de-spread that certain spread spectrum signal and recover a first symbol, and wherein the control circuit grants a second time divided access to the symbol combining stage to de-rotate that first symbol of the certain spread spectrum signal. - View Dependent Claims (18, 19, 20, 21, 22)
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Specification