Common channel interference cancellation for a spread spectrum system

Abstract

Abstmcl-Investigating advanced signal processing algorithms for existing and future wireless systems, this paper has mainly focussed on evaluating the potential performance improvements that accrue from cancelling the common pilot channel's interference in terms of hit error rate performance for downlink applications. The impact of different cancellation strategiessequential (SIC) and parallel (PIC) -has been presented for various data rates and channel profiles. With the investigative analysis appertaining to the FDD element of the UTRAN specified by 3GPP, the performance of the interference cancellation unit is primarily based on the elimination of the cross-correlation of the spreading codes over time dispersive wireless conditions. With a sound channel estimate, the results are shown to achieve near interference free performance highlighting the potentiality of these interference cancellation schemes. Their versatility and robustness against channel estimation errors is further demonstrated by a relative performance comparison for a diversified range of data rates, pilot-to-data power ratios and channel conditions.

Performance enhancement analysis for a DS-CDMA system

“…A similar performance improvement pattern can be observed for case 1 and case 4, and a further analysis (studying the effect of path profile variation) can be found in [7].…”

“…The effect of varying the spreading factor (SF) and channel path profiles have already been investigated and presented in [7]. In brief, the following conclusions were drawn:…”

“…Further details about the description of the simulation model can be found in [7]. Some of the key simulation parameters have been characterised in Table I.…”

“…SIC works on the principle of removing the interference on a specific path from relatively stronger ones, whereas PIC performs interference cancellation from all paths irrespective of their path strengths. Further details about these algorithms can be found in [7].…”