TITLE: Development and test of a Satcom IP modem for the EHF band

In 2008, the French MoD started the development of a protected modem (EPM) fitted with an IP interface. This modem was designed to provide an efficient use of the EHF resources (44/21 GHz). It will lead to an operational use of this frequency band in order to cope with the lack of SHF frequency resources. Contrary to the SHF concept of operation where links are planned with constant data rates and static margins, the EHF band requires the use of dynamic Link adaptation Techniques to adapt to propagation conditions and so reduce the link margins. This modem is derived from the frequency hopped EPMt modem developed for the SHF band. Additional features have been added for EHF band: (1) Dynamic Link Adaptation (= CADE for the French acronym) function and a Power Control function (CAPE) (2) Ethernet Interface The modem has been tested in lab on the test bench developed by the French company THALES. Additional tests with a real terminal developed also for the EHF band are being achieved this year through an EHF transponder on our satellite SYR3A. The different tests have shown that all the transmission profiles are compliant with the specified performances; the Dynamic Link Adaptation function works correctly with real EHF profiles featuring fading.