Multiuser detectors suffer from their relatively higher computational complexity that prevents widespread use of this technique. In addition, one of the main characteristics of multichannel communications that can severely degrade the performance is the inconsistent values of processing gain (PG) that result in high multiple access interference (MAI). However, if we could lower the complexity of multiuser detectors and produce better values of PG, most of the CDMA systems would likely take advantage of this technique in terms of increased system capacity and a better data rate .This paper presents a deterministic formalization of the PG for a wireless multi-channel DS-CDMA system. The proposed deterministic formalization demonstrates that how the reduced BER could be used to achieve reasonable values of PG by which unwanted signals can be suppressed relative to the desired signal at the receiving end. The performance measure adopted in this paper is the achievable bit rate for a fixed probability of error (10-7).