On ping-pong effects in linear interference cancellation for CDMA

In this paper we formulate a general iterative form to described hybrid interference cancellation, a concept which includes both successive interference cancellation (SIC) and parallel interference cancellation (PIC) as its two extreme cases. Furthermore, the ping-pong effect commonly observed in linear PIC is studied in detail and is shown to be a direct consequence of the extreme eigenvalues of the iteration matrix. Intervals for the dominating eigenvalues within which ping-pong is likely to occur are specified. These intervals are then used to determine weighting factors for partial cancellation such that ping-pong effects are avoided.