Code-division multiple-access receiver with sequential interference-canceling architecture

A code-division multiple-access receiver for receiving a code-division multiple-access signal combining signals of a plurality of stations, each station having a different spreading code and a corresponding despreading code, comprising:

• a front-end circuit for converting said code-division multiple-access signal to a baseband signal;
• a controller coupled to said front-end circuit, for recognizing symbol boundaries in said baseband signal;
• and
• a baseband processor coupled to said front-end circuit, for receiving said baseband signal, storing successive one-symbol portions of said baseband signal, despreading said one-symbol portions of said baseband signal to generate estimated symbol values, respreading said estimated symbol values to generate estimated interference signals, and modifying said baseband signal by subtracting said estimated interference signals, these processes of despreading, respreading, and modifying being carried out in a cyclic order responsive to symbol boundaries recognized by said controller.

A code-division multiple-access receiver for receiving a code-division multiple-access signal combining signals of a plurality of stations, each station having a different spreading code and a corresponding despreading code, comprising:

• a front-end circuit for converting said code-division multiple-access signal to a baseband signal;
• a shift register coupled to said front-end circuit, for receiving, storing, and shifting said baseband signal;
• a controller coupled to said front-end circuit, for recognizing symbol boundaries in said baseband signal;
• a symbol memory for storing estimated symbol values;
• and
• a baseband processor coupled to said shift register and said symbol memory, for reading from said shift register a part of said baseband signal corresponding to one symbol, generating a spreading code by which said symbol was spread, generating a corresponding despreading code, using said part of said baseband signal and said despreading code to generate an estimated symbol value storing said estimated symbol value in said symbol memory, using said spreading code to generate an estimated interference signal, and modifying said part of said baseband signal in said shift register by subtracting said estimated interference signal.