To begin with, the mobile network was planned almost exclusively for voice communication, however, mobile data usage has become increasingly important over the years, especially with the advent of smart phones and tablets. This is also a major reason behind the rapid development of mobile communication standards. Whereas standards such as GPRS or EDGE only enable transmission speeds in the kilobits per second range, modern mobile networks, with 3G or 4G technology, such as UMTS and LTE, achieve bandwidths of many megabits per second. The LTE standard allows transfer rates of more than 100 megabits per second and, by using various different frequency ranges, can cover a large area around the radio mast.
Thanks to mobile phone networks and modern cloud telephone systems, mobile communication devices can be easily integrated intotelephone systems. The mobile device can connect to the cloud telephone system both via a standard connection through the cellular network, as well as via Wifi. An appropriate client app on the mobile device can make it reachable via a landline number. Also, system functions, such as call waiting, conferencing or switching functions, can be enabled between the cloud telephone system and the mobile network. To enable billing for calls made by mobile users via the central telephone system, features such as Call-Through or Call-Back are available. When changing the type network a mobile user is connected to, a technology called handover allows the conversation to continue uninterrupted.