Joint delay tracking and interference cancellation in DSCDMA systems using successive ICA for oversaturated data Recent studies have found successive interference cancellation (SIC) schemes employing blind source separation (BSS) methods to be promising competitors for conventional interference cancellation schemes in DSCDMA systems. One reason for this is the inherent ability of BSS to mitigate many kinds of interference sources e.g. multiaccess, multipath and outofcell interferences. In addition, more sources than observationsproblem can be somewhat circumvented by combining the SICideology to BSS. Hence, BSSSIC type receivers can be used also in highly loaded systems where both conventional ICA and conventional interference cancellation usually fails. Recently proposed BSSSIC receivers have needed accurate estimates for the user delays. This is mandatory for any interference canceller, since subtraction of a inaccurately estimated source from the original data actually enhances interference. In this paper we propose a scheme in which the ICA solution is used to tracking of usersu0027 delays, too, which helps to avoid the performance losses due to the inaccuracies in conventional delay tracking circuitry.

Performance Evaluation of IDMABased Random Access Considering User Detection and Channel Estimation This paper evaluates the performance of interleave division multiple access (IDMA)based random access in order to support massive machinetype communications (mMTC) in the fifth generation mobile communication system taking into account actual user detection and channel estimation using a preamble attached to the packet. To suppress the packet loss due to contention and achieve multipacket reception, accurate user detection and channel estimation, which are used in the successive interference canceller (SIC)process in IDMA, are essential. Multiple preamble sequences, each of which has a onetoone relationship with the interleaver pattern prepared in the system, are generated by applying a cyclic time shift and orthogonal masking operations to ZadoffChu (ZC) sequences. Based on the threshold decision on the correlation between the received signal and each preamble sequence, user detection and channel estimation are performed. Computer simulation results show the impact of the preamble overhead, miss detection and false alarm in the user detection, channel estimation error, and the case when multiple users simultaneously select the same interleaver on the achievable performance of IDMAbased random access.