Sub-symbol parallel inteference cancellation
AssigneeThe MITRE Corporation
InventorsJames Dunyak, John Fite, Jerome Shapiro
Life of this patent
Estimating the term…
Abstract
Reduction of multiple access interference, in one example for asynchronous CDMA systems using long codes. In one aspect, parallel interference cancellation (PIC) implements a decoupled estimate, preferably non-linear and applied at chip intervals. According to another aspect, interference is cancelled using a technique that estimates bits for a symbol by interpolating signature waveforms for users to a common sampling lattice of the received data. According to another aspect, multi-stage, hybrid multi-stage, and reconfigurable recursive multi-stage multi-user detection architectures and corresponding processes are provided.
Claims88
A method for canceling multiple user interference in a communications system wherein a plurality of users communicate over a shared channel, the method comprising:
- receiving an input that provides a plurality of discrete values produced at sub-symbol intervals that are less than a full symbol period, wherein a current discrete value corresponds to a current sub-symbol interval for a current symbol and a previous discrete value corresponds to a previous sub-symbol interval for the current symbol;
- and
- estimating symbols for a given user from the plurality of users at sub-symbol intervals, wherein a current estimation for the given user estimates a portion of the current discrete value that corresponds to the current symbol for the given user and cancels interference produced by the plurality of users as determined from the previous discrete value during the previous sub-symbol interval.
An apparatus for canceling multiple user interference in a communications system wherein a plurality of users communicate over a shared channel, the method comprising:
- an input that receives a plurality of discrete values produced at sub-symbol intervals that are less than a full symbol period, wherein a current discrete value corresponds to a current sub-symbol interval for a current symbol and a previous discrete value corresponds to a previous sub-symbol interval for the current symbol;
- and
- a first processing stage, in communication with the input, that estimates symbols for a given user at sub-symbol intervals, wherein a current estimation for the given user estimates a portion of the current discrete value that corresponds to the current symbol for the given user and cancels interference produced by the plurality of users as determined from the previous discrete value during the previous sub-symbol interval.
A computer program product for canceling multiple user interference in a communications system wherein a plurality of users communicate over a shared channel, the computer program product stored on a computer readable medium and adapted to perform operations comprising:
- receiving an input that provides a plurality of discrete values produced at sub-symbol intervals that are less than a full symbol period, wherein a current discrete value corresponds to a current sub-symbol interval for a current symbol and a previous discrete value corresponds to a previous sub-symbol interval for the current symbol;
- and
- estimating symbols for a given user from the plurality of users at sub-symbol intervals, wherein a current estimation for the given user estimates a portion of the current discrete value that corresponds to the current symbol for the given user and cancels interference produced by the plurality of users as determined from the previous discrete value during the previous sub-symbol interval.
A method for canceling multiple user interference in a communications system wherein a plurality of users communicate over a shared channel, the method comprising:
- receiving an input that provides a plurality of discrete values produced at sub-symbol intervals that are less than a full symbol period, wherein a current discrete value corresponds to a current sub-symbol interval for a current multiple bit symbol and a previous discrete value corresponds to a previous sub-symbol interval for the current multiple bit symbol;
- and
- estimating symbols for a given user from the plurality of users at sub-symbol intervals, wherein a current estimation for the given user estimates a portion of the current discrete value that corresponds to the current multiple bit symbol for the given user and cancels interference produced by the plurality of users as determined from the previous discrete value during the previous sub-symbol interval.
An apparatus for canceling multiple user interference in a communications system wherein a plurality of users communicate over a shared channel, the method comprising:
- an input that receives a plurality of discrete values produced at sub-symbol intervals that are less than a full symbol period, wherein a current discrete value corresponds to a current sub-symbol interval for a current multiple bit symbol and a previous discrete value corresponds to a previous sub-symbol interval for the current multiple bit symbol;
- and
- a first processing stage, in communication with the input, that estimates symbols for a given user at sub-symbol intervals, wherein a current estimation for the given user estimates a portion of the current discrete value that corresponds to the current multiple bit symbol for the given user and cancels interference produced by the plurality of users as determined from the previous discrete value during the previous sub-symbol interval.
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Dependencies are inferred from the claim text.