Radio access technology

A radio access technology (RAT) is the underlying physical connection method for a radio communication network. Many modern mobile phones support several RATs in one device such as Bluetooth, Wi-Fi, and GSM, UMTS, LTE or 5G NR.

The term RAT was traditionally used in mobile communication network interoperability.<ref name="Virtej"> I. Virtej; S. Hamiti; T.A. Rantalainen; J. Parantainen; G. Sebire; E. Nikula (November 2001). "Radio resource control for GSM/EDGE Radio Access Network (GERAN)-inter radio access technology and inter-mode procedures". IEEE 54th Vehicular Technology Conference. VTC Fall 2001. Proceedings (Cat. No.01CH37211). Vol. 3. pp. 1417–1421. doi:10.1109/VTC.2001.956430. ISBN 0-7803-7005-8. S2CID 9731093.</ref> More recently, the term RAT is used in discussions of heterogeneous wireless networks.<ref>S. O. Holland, A. Aijaz, F. Kaltenberger, F. Foukalas, G. Vivier, M. Buczkowski and S. Pietrzyk"[https://ieeexplore.ieee.org/abstract/document/7565257 Management architecture for aggregation of heterogeneous systems and spectrum bands ]." IEEE Communications Magazine ( Volume: 54 , Issue: 9, Sep. 2016, pp. 112–118.</ref> The term is used when a user device selects between the type of RAT being used to connect to the Internet. This is often performed similar to access point selection in IEEE 802.11 (Wi-Fi) based networks.<ref name="helou"> Melhem El Helou; Samer Lahoud; Marc Ibrahim; Kinda Khawam (April 2013). "A Hybrid Approach for Radio Access Technology Selection in Heterogeneous Wireless Networks". 19th European Wireless Conference -Proceedings. Archived from the original (PDF) on 7 October 2003. Retrieved 2013-10-07.</ref>

Inter-RAT (IRAT) handover

A mobile terminal, while connected using a RAT, performs neighbour cell measurements and sends measurement report to the network. Based on this measurement report provided by the mobile terminal, the network can initiate handover from one RAT to another, e.g. from WCDMA to GSM or vice versa. Once the handover with the new RAT is completed, the channels used by the previous RAT are released.<ref>"IRAT handover basics | WCDMA to GSM IRAT handover".</ref>

See also

• Radio access network (RAN)