Effect of channel estimation and multipath on interference cancellation employing blind source separation in the DS-CDMA uplink

Abstract

Absfruc-In this paper we consider DS-CDMA uplink interference cancellation hased on blind source separation (BSS) technique. While BSS assisted interference suppresion compared to linear receivers is quite well reported, a comparison of BSS with nonlinear receivers is overlooked in the literature. 1111 wa7 the first one to make this comparison in AWGN channel with perfect channel information. In this paper we make further evaluation. Especially, the effect7 of multipaths, related channel estimation errors and additional external interference (like adjacent channel interference or intentional jamming) are examined and compared to conventional successive interference cancellation (SIC) and &I-stage parallel interference cancellation (PIC) k h a n s . We demonstrate hy numerical experiment7 that henefib of using BSS exists. Moreover, results indicate that the performance gain compared to SIC and PIC is even greater in multipath scenario and in the presence of channel estimation imperfections.

Independent component analysis using successive interference cancellation for oversaturated data

“…Recall that a single-path channel was assumed because of simplicity. However, it was shown in Reference [17] that increasing the number of propagation paths does not have an essential influence on ICA separation. In fact, it was found out that a greater number of paths result in a slightly more reliable separation compared to single-path scenario.…”

“…Since a sum is y Similar representation for the data can be easily derived also in case of multipath channels. [9,17]. Hence, a single-path data model is assumed here without loss of generality.…”

Dual‐antenna‐based blind joint hostile jamming cancellation and multi‐user detection for uplink of asynchronous direct‐sequence code‐division multiple access systems

“…Investigations on blind MUD of DS-CDMA systems in the presence of hostile jamming have been carried out in [14][15][16][17][18]. They can be divided into two categories.…”

“…These two schemes are applicable to additive white Gaussian noise (AWGN) channel and multi-path channel, respectively. The other category detectors, such as proposed in [16][17][18], are not only valid for downlink but also valid for uplink of CDMA systems. In [16], Ho et al proposed a blind MUD scheme to combat partial-band jamming by a linear predictor.…”

“…In addition, our scheme only requires two receive antennas, but the number of antennas, which the detector in [15] requires, is larger than the number of paths of the multi-path channel. Although the detectors proposed in [17,18] are also valid for both downlink and uplink of DS-CDMA system, the assumption that the jamming keeps constant during one symbol duration restricts their implementation. Our work is differentiated in that we treat the jamming as multiple signals by transforming it into parallel instead of approximating it as a signal that keeps constant during one symbol duration; therefore our scheme will perform better than the schemes proposed in [17,18].…”