MULTI-USER DETECTOR FOR DIRECT SEQUENCE - CODE DIVISION MULTIPLE ACCESS (DS/CDMA) CHANNELS

摘要

Present invention incorporates Multiuser Detections and packet assembling. In Multiuser Detection, receiver joint demodulation user data passes through the structure using multi-user interference, package close be a kind of standard automatic repeat request protocol enhancing, wherein the grouping to malfunction is not dropped, but save and with those of retransmit to improve subsequent judgement. In one embodiment of two-stage detector, using the first stage, wherein grouping is combined and then decodes, with improve provisional ruling for interfere elimination. Then it is offset and is interfered with the decoder output second level, before being then combined again, final decoding. Hierarchical detection, it is contemplated that the first stage of two decoding schemes. One is the decoded soft-combine grouping of soft input/soft output maximum a posteriori probability, then executes interference and eliminate in the second level. In this second embodiment, we are decoded using hard decision Viterbi/Turbo, and are done something in disregard of obstacles to disturb and eliminated the second level. We include power, quantization and time, phase and amplitude estimation in simulation. This result shows that, the common proposed projects using packet assembling and Multiuser Detection significantly improve the performance of high channel load, increase the robustness of system.