SMS over LTE : interoperability between legacy and next generation networks

Abstract

To increase the trust and acceptance of Next Generation Networks (NGN) by new and existing subscribers, it is necessary to ensure that the most popular services of legacy networks (GSM/GPRS) are still in place. The Short Message Service (SMS) is a widespread data service with high revenue for telecommunication operators, which allows the exchange of short messages between fixed, mobile and, indirectly, Internet subscribers. In this context, it is essential to extend this service for the NGN and allow its interaction with the new messaging services. With that in mind, a study was carried out to ensure the coexistence between SMS and the Instant Messaging (IM) service present in NGN. The present study identifies the relevant technical specifications impacting on the functionality of the IP Multimedia Subsystem (IMS) messaging services so that the interoperability with SMS can be ensured. The results of this study, covered in this article, aim to help the comprehension of the proposed interoperability solution, and demonstrate that the exchange of messages between legacy and NGN messaging services or equipment can be successfully accomplished. In this context, both SMS and IMS messaging services are detailed, along with the main protocols they involve. Finally, the entity responsible for ensuring message interoperability - the IP Short Message Gateway (IP-SM-GW) - is presented and tested in a commercial delivery content testbed.