This paper focuses on the study of schemes that improve the through performance of a conventional DS-CDMA packet data network, and in particular, eliminate, or drastically mitigate, bistability that arises fropm interference. Two schemes are consideed: spreading gain control (SGC) and incremental redundancy (IR). Under SGC, the spreading gains of the users are varied in response to changing intereference conditions. Under IR, when a packet with uncorrectable errors is received, it is not discrarded but combined with retrans-mitted packets via bit-by-bit adition of the corresponding mathced filter ouputs. The IR scheme is related to SGC at some level, but requires no estimation of the interference. It is shown that the SGC system prossesses a single equilibrim. The IR system may posses multiple equilibria. Numerical results show, however, that the equilibria are typically close together toward the origin. It is shown that, if there is only a single equilibrium, then under certain conditions, there exists a time T such that, for a IR system with a sufficiently large number of user, the system is whitin any given neighborhood of this equilibrium point with high probability for all times greater than T. An analyogous results holds for SGC.
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