Substandard cell phones: impact on network quality and a new method to identify an unlicensed IMEI in the network

The increase of counterfeit mobile phones in wireless networks on emerging markets is one of the reasons for the degradation in spectral efficiency. In some countries the sales of counterfeit/ substandard phones could represent as much as 15-20 percent of the market [1]. The motivation of this article is to have a better understanding of the impact of counterfeit phones on network performance and present a solution to identify these mobile devices. Several laboratory tests and implementations emulating a real cellular coverage were performed. Results showed that counterfeit phones have degraded quality service for the user and also impact other subscribers (14 dB sensitivity difference from the original). Additionally, higher dropped calls and access failures rates (up to three times more) were observed. A new method that can identify, notify the user of, and block counterfeit devices was implemented and tested in the laboratory. This article presents several aspects that impact network reliability, as well as an innovative method to manage the access of substandard devices to cellular networks that can bring more efficient usage of spectrum resources.