A New Resynchronization Signal Design for Re1-15 LTE-M

Minimizing the resynchronization time in Long-Term Evolution for Machine Type Communications (LTE-M) is highly desirable to enhance the battery lifetime of low-power and possibly deep-coverage user equipments (UEs) targeting Internet-of-Things (IoT) applications. This has led the 3rd Generation Partnership Project (3GPP) to initiate a work item in Re1-15 LTE-M to improve cell search and/or system information acquisition time. This has been accomplished by developing a new resynchronization signal (RSS) that can be detected during relatively short device wake-up times and with low computational effort. In this paper, we review the design aspects that have been considered while deriving the new RSS signal and describe the RSS design that has been adopted by 3GPP. Moreover, we propose another RSS design and show the differences between the proposed design and the one adopted by 3GPP in terms of the detection performance and the computational and memory complexity. Finally, we highlight the gains resulting from employing the new RSS design compared to the legacy synchronization signals.