US 6,480,482 B1Granted

Multi-user interference cancellor with small sized circuits and little quantity of calculation

AssigneeNEC Corporation

InventorTakashi Shoji

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Abstract

In the particular one of interference canceling stages of the multi-user interference cancellor of the parallel processing type, the IEUs reproduce the symbol replica signals from the input signal of the stage, and also produce the local spread signals. The local spread signals have result information of the reproduction in only the IEUs, respectively, and have not been subjected to filtering, yet. Such local spread signals are multiplexed into the multiplexed signal, and then, is subjected to amplitude limitation, to be the amplitude limited signal. After then, the amplitude limited signal is filtered by the filter, to be input into the subtracter. The subtracter subtracts the filtered signal from the input signal of this stage, and thereby, to produce the output of this stage.

Claims12

Dependent claims

A multi-user interference cancellor, operable in response to a multi-user spread signal having a plurality of spread user-signals, to produce user-signals in correspondence with the spread user-signals, said cancellor comprising a plurality of interference canceling stages each of which is adapted to reproduce symbol replica signals corresponding to the user-signals in response to an input signal of each of the interference canceling stages and which is adapted to produce a remnant component of the multi-user spread signal as an output signal of each interference canceling stage, wherein:

each of the interference canceling stages except for the last one comprises:
a plurality of interference estimation units (IEUs) which are equal in number to processable user-signals, to produce the symbol replica signals corresponding to the user-signals assigned to the IEUs and, wherein said IEUs also produce local spread signals having result information from processing in only said IEUs respectively;
a processor adapted to process the local spread signals, to calculate, from them, a single vector signal which is obtained by a combination of the local signals;
and
a subtracter adapted to subtract the single vector signal from the input signal, and thereby, to produce the output signal representative of the remnant component;
and
wherein the last interference canceling stage produces the user-signals from the symbol replica signals and the output signal, all produced by a preceding one of the interference canceling stages.

4 more elements

Dependencies are inferred from the claim text.