Communication device and method for interference suppression in a DS-CDMA system

A method for receiving signals in a DS-CDMA communication system, the method comprising the steps of:

• providing a RAKE receiver having a plurality of receiver fingers;
• identifying a first multipath element;
• assigning a first receiver finger to the first multipath element;
• demodulating the first multipath element;
• identifying a second multipath element;
• assigning a second receiver finger to the second multipath element;
• suppressing interference from a base station corresponding to delay of the second multipath element and identified by the second receiver finger;
• and
• otherwise, demodulating the second multipath element for combination with other multipath elements.

A method for receiving radio signals at a receiver, the method comprising the steps of:

• (a) receiving a plurality of signals;
• (b) determining a signal quality parameter for each of the plurality of signals;
• (c) ranking the plurality of signals according to the signal quality parameter and selecting signals according to a predetermined criteria;
• (d) suppressing the selected signals according to rank;
• and
• (e) combining remaining signals as received data.

A communication system comprising:

• a base station which transmits radio frequency (RF) signals, the RF signals formed by mixing a baseband signal with an RF carrier, the baseband signal being formed by spreading symbols with a periodic spreading sequence having a period substantially greater than a number of chips per symbol;
• and
• a mobile station including
• a receiver which receives the RF signals, producing downconverted RF signals,
• an interference ranking circuit for identifying interference, and
• an interference suppression correlator which completely suppresses the interference while demodulating the downconverted RF signals, producing received data.

A method for receiving data from a remote transmitter in a communication system, the method comprising the steps of:

• receiving at a receiver a desired code;
• detecting interference at the receiver;
• calculating an orthogonal projection of the desired code in response to the interference;
• and
• demodulating received data from the remote transmitter using the orthogonal projection.

A method for receiving radio symbols at a communication device, the method comprising the steps of:

• (a) receiving a plurality of signals corresponding to a set of multipath delay elements;
• (b) determining a signal quality parameter for each of the set of multipath delay elements;
• (c) selecting a subset of the set of multipath delay elements in soft handoff with the communication device for combining according to the signal quality parameter;
• (d) for each of the subset of multipath delay elements, being combined, selecting a set of interfering signals to be suppressed;
• and
• (e) combining the selected subset of multipath delay elements after suppressing the set of interfering signals to be suppressed.