Frame-extended linear decorrelating detector for asynchronous CDMA

The standard linear decorrelating detector (LDD) for asynchronous code-division multiple access involves complicated computations and long detection delay. The one-shot LDD with a frame of 1-bit period length leads to a simpler architecture with less than 1-bit detection delay but significant noise enhancement compared with the standard LDD. In this paper, extending the frame to more than one bit period, a frame-extended LDD (FELDD) is proposed. With a slight increase of complexity and detection delay, the noise enhancement of the FELDD is greatly reduced compared with the one-shot LDD and approaches that of the standard DD. The total number of users supported is also increased compared with that of the one-shot LDD. Theoretical analysis and computer simulations are used to demonstrate the feasibility of the proposed scheme.