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GSM base stations

Integrating GSM & WLAN

Providing special WiFi solutions since years - e.g. our Integrated Radio Masts - brown-iposs realized a major enhancement by integrating GSM small cells with WLAN access points. The GSM small cell - a sysmoBTS - can be fully integrated in our radio masts and can also be deployed in closed indoor areas.

By the integration of GSM and WLAN an easy and secure access to the WiFi network can be provided. Mobiles, smartphones, and tables with cellular support can directly access the WiFi network without any further authentication. Transmitted data is encrypted already when accessing the WiFi network for the first time.


The sysmoBTS is a low-power and small-formfactor IP-backhaul GSM BTS provided by sysmocom. It is suitable for a wide range of applications, like private GSM networks (PBX style use), in-building coverage extension, or for rapidly deployed rural cellular networks, e.g. for crisis intervention. It supports 850/900/1800/1900 MHz bands and is therefore compatible with any available GSM-handset.

The sysmoBTS is permitting to run a completely autonomous small GSM network from within the BTS and does not require an external BSC/MSC/HLR/VLR. Due to this flexibility it is a good starting point for interfacing with other components like WiFi-access points. Since it is built on open source software it can be enhanced by own approaches.

Common authentication - EAP-SIM

Todays authentication in WiFi networks is either insecure, complicated, or inconvenient - at least for mobile scenarios. In cellular networks this issue is solved by the usage of SIM-cards. A convenient solution for devices which support cellular and WiFi-networks - like any smartphone today - is provided by the EAP-SIM protocol. EAP-SIM has been developed by 3GPP and proposed as an RFC standard already in 2006.

For brown-iposs integrated GSM & WLAN network therefore EAP-SIM protocol is used. Without any modifications on the handset or without the need of specially developed apps or even rooted handsets secure data connection with high bandwidth can be provided.