Mobility solutions require the use of wireless technologies, which enables users to roam freely, while still being in touch with the necessary back-end office infrastructure. Generally speaking, wireless is an old-fashioned term for a radio transceiver (a mixed receiver and transmitter device), referring to its use in wireless telegraphy early on, or for a radio receiver. Now the term is used to describe modern wireless connections such as those in cellular networks and wireless broadband internet, mainly using radio waves.
The wireless technologies used in mobility solutions can generally be classified according to their generation, which largely specifies the type of services and the data transfer speeds of each class of technologies.
Zero Generation (0G – 0.5G)
Mobile radio telephone systems preceded modern cellular mobile telephony technology. Since they were the predecessors of the first generation of cellular telephones, these systems are sometimes referred to as 0G (zero generation) systems. Technologies used in 0G systems included PTT (Push to Talk), MTS (Mobile Telephone System), IMTS (Improved Mobile Telephone Service), AMTS (Advanced Mobile Telephone System), OLT (Norwegian for Offentlig Landmobil Telefoni, Public Land Mobile Telephony) and MTD (Swedish abbreviation for Mobilelefonisystem D, or Mobile telephony system D).
These early mobile telephone systems can be distinguished from earlier closed radiotelephone systems in that they were available as a commercial service that was part of the public switched telephone network, with their own telephone numbers, rather than part of a closed network such as a police radio or taxi dispatch system.
These mobile telephones were usually mounted in cars or trucks, though briefcase models were also made. Typically, the transceiver (transmitter-receiver) was mounted in the vehicle trunk and attached to the “head” (dial, display, and handset) mounted near the driver seat. They were sold through various outlets, including two-way radio dealers. The primary users were loggers, construction foremen, realtors, and celebrities, for basic voice communication.
First Generation (1G)
Most of the devices which came from this generation had military as its origin and then moved to civilian services. 1G is short for first-generation wireless telephone technology, or mobile phones. These are the analogue mobile phone standards that were introduced in the 1980s and continued until being replaced by 2G digital mobile phones. Some of the 1G standards include NMT (Nordisk MobilTelefoni or Nordiska MobilTelefoni-gruppen, Nordic Mobile Telephone in English), AMPS (Advanced Mobile Phone System), Hicap, CDPD (Cellular Digital Packet Data, Mobitex and DataTAC.
Second Generation (2G – 2.75G)
The main difference between the two succeeding mobile telephone systems, 1G and 2G, is that the radio signals that 1G networks use are analogue, while 2G networks are digital. Note that both systems use digital signalling to connect the radio towers (which listen to the handsets) to the rest of the telephone system. But the call itself is encoded to digital signals in 2G whereas 1G is only modulated to higher frequency (typically 150 MHz and up).
All the standards belonging to this generation are commercial centric and they are digital in form. Two main groups have evolved one from Europe and another from America. Around 60% of the current market is dominated by European standards. The second generation standards include:
- GSM (Global System for Mobile Communications) is the most popular standard for mobile phones in the world. GSM service is used by over 2 billion people across more than 212 countries and territories. The ubiquity of the GSM standard makes international roaming very common between mobile phone operators, enabling subscribers to use their phones in many parts of the world. GSM differs significantly from its predecessors in that both signalling and speech channels are Digital call quality. This fact has also meant that data communication was built into the system from very early on.
- GPRS (General Packet Radio Service) is a mobile data service available to users of GSM mobile phones. It is often described as “2.5G”, that is, a technology between the second and third generations of mobile telephony. It provides moderate speed data transfer, by using unused TDMA channels in the GSM network. The theoretical limit for packet switched data is 171.2 kbit/s (using 8 time slots and CS-4 coding). A realistic bit rate is 30–80 kbit/s, because it is possible to use max 4 time slots for downlink.
- EDGE (EGPRS) (Enhanced Data rates for GSM Evolution) is a digital mobile phone technology which acts as a bolt-on enhancement to 2G and 2.5G General Packet Radio Service (GPRS) networks. This technology works in GSM networks. EDGE is a superset to GPRS and can function on any network with GPRS deployed on it, provided the carrier implements the necessary upgrades.
- HSCSD (High-Speed Circuit-Switched Data), iDEN (Integrated Digital Enhanced Network, D-AMPS (Digital AMPS), IS-95, PDC (Personal Digital Cellular), CSD (Circuit Switched Data), PHS (Personal Handy-phone System), WiDEN (Wideband Integrated Dispatch Enhanced Network) and CDMA2000 (1xRTT/IS-2000)
Third Generation (3G – 3.75G)
The services associated with 3G provide the ability to transfer simultaneously both voice data (a telephone call) and non-voice data (such as downloading information, exchanging email, and instant messaging). The systems in this standard are basically a linear enhancement of 2G systems. Currently, transition is happening from 2G to 3G systems. Some of the 3G standards include:
- UMTS (3GSM) (Universal Mobile Telecommunications System) uses W-CDMA as the underlying standard, is standardized by the 3GPP, and is the European answer to the ITU IMT-2000 requirements for 3G Cellular radio systems. UMTS supports up to 11 Mbit/s data transfer rates in theory, although at the moment users in deployed networks can expect a performance up to 384 kbit/s for R99 handsets, and 1-2 Mbit/s for HSDPA handsets in the downlink connection.
- 5G – HSDPA (High-Speed Downlink Packet Access) is a mobile telephony protocol, which provides a smooth evolutionary path for UMTS-based 3G networks allowing for higher data transfer speeds. Current HSDPA deployments support 1.8 MBit/s or 3.6 MBit/s in downlink. Further steps to 7.2 MBit/s and beyond are planned for the future.
- W-CDMA (Wideband Code Division Multiple Access), FOMA (Freedom of Mobile Multimedia Access), 1xEV-DO/IS-856 (1x Evolution-Data Optimized), TD-SCDMA (Time Division-Synchronous Code Division Multiple Access), GAN/UMA (Generic Access Network), 3.75G – HSUPA (High-Speed Uplink Packet Access.
Fourth Generation (4G)
According to 4G working groups, the infrastructure and the terminals will have almost all the standards from 2G to 3G implemented. The system will also serve as an open platform where the new innovations can go with it. Some of the standards which pave the way for 4G systems include:
- 3GPP LTE (Long Term Evolution) (The 3rd Generation Partnership Project) is a collaboration agreement that was established in December 1998. It is a co-operation between ETSI (Europe), ARIB/TTC (Japan), CCSA (China), ATIS (North America) and TTA (South Korea). The scope of 3GPP is to make a globally applicable 3G mobile phone system specification within the scope of the ITU’s IMT-2000 project.
- WiMax and WiBro.