In the wireless sector maintenance costs form a large part of the total network operating cost. This paper presents a possible proactive maintenance scheme for wireless systems. The object of this paper is to reduce the high operational costs encountered in the wireless industry by decreasing maintenance costs and system downtime. An on-line monitoring system is suggested to identify performance degradation, as well as its possible sources via symbol frequency distribution analysis. In this paper a single fault mechanism is considered and the methodology to detect and diagnose the fault mechanism is presented. With similar analysis for other fault mechanisms, this system could ensure that maintenance occurs only when necessary and not at routine intervals.