Synchronous demodulation apparatus of base transceiver station in interim standard-2000 system
AssigneeCuritel Communications, Inc.
InventorJin-Il Kim
Life of this patent
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Abstract
The present invention provides a synchronous demodulation apparatus of a base transceiver station in an Interim Standard-2000 (IS-2000) system, including a first synchronous demodulation unit, a received signal delay unit, an interference signal regeneration unit and a second synchronous demodulation unit. In comparison with an asynchronous demodulation apparatus used in an Interim Standard-95 (IS-95), it is possible for the inventive apparatus to improve a reception function approximately 3 dB and ultimately increase the number of subscribers.
Claims4
A synchronous demodulation apparatus of a base transceiver station in an Interim Standard-2000 (IS-2000) system, comprising:
- a first synchronous demodulation unit for receiving received signals r(t) each of which includes a pilot channel signal and a traffic channel signal, demodulating the received signals r(t) to generate demodulated signals (d′1, . . . , d′k) which corresponds to ‘k’ numbers of mobile stations, and outputting the demodulated user signals;
- a channel estimation unit for estimating channel parameters (A1(t-Tb), . . . , Ak(t-Tb) for each of the mobile stations based on the pilot channel signals transmitted from the mobile stations, and generating estimated channel parameters;
- a received signal delay unit for delaying the received signal r(t) and outputting a delayed signal r(t-Tb) which is delayed in one symbol (Tb) from the received signal r(t);
- an interference signal regeneration unit for generating interference signals corresponding to ‘k’ numbers of subscribers based on the demodulated user signals (d′1, . . . , d′k) and the estimated channel parameters, removing interference signals corresponding to the ‘k’ numbers of the subscribers from the delayed signals r(t-Tb), and outputting interference-cancelled-signals (r′1(t-Tb), . . . , r′k(t-Tb)) in which the interference signals are removed;
- and
- a second synchronous demodulation unit for demodulating the interference-cancelled-signals (r′1(t-Tb), . . . , r′k(t-Tb)) and outputting demodulated signals.
A synchronous demodulation method applied to a base transceiver station in an Interim Standard-2000 (IS-2000) system, the method comprising the steps of:
- a) receiving received signals r(t) each of which includes a pilot channel signal and a traffic channel signal, demodulating the received signals r(t) to generate demodulated signals (d′1, . . . , d′k) which corresponds to ‘k’ numbers of mobile stations, and outputting the demodulated user signals;
- b) estimating channel parameters (A1(t-Tb), . . . , Ak(t-Tb) for each of the mobile stations based on the pilot channel signals transmitted from the mobile stations, and generating estimated channel parameters;
- c) delaying the received signal r(t) and outputting a delayed signal r(t-Tb) which is delayed in one symbol (Tb) from the received signal r(t);
- d) generating interference signals corresponding to ‘k’ numbers of subscribers based on the demodulated user signals (d′1, . . . , d′k) and the estimated channel parameters, removing interference signals corresponding to the ‘k’ numbers of the subscribers from the delayed signals r(t-Tb), and outputting interference-cancelled-signals (r′1(t-Tb), . . . , r′k(t-Tb)) in which the interference signals are removed;
- and
- e) demodulating the interference-cancelled-signals (r′1(t-Tb), . . . , r′k(t-Tb)) and outputting demodulated signals.
Dependencies are inferred from the claim text.