The Enhanced Bandwidth Efficient Modem (EBEM) for military satellite communications (SATCOM) rollout is currently underway, with more than 2,300 EBEMs to be fielded by the end of 2008 under a joint Army-Navy program to replace legacy modems.


EBEM makes better use of SATCOM resources, in terms of power and bandwidth, and its advanced capabilities will enable Net Centric warfare, according to project leader Johnny Ng with Defense Communications and Army Transmission Systems (DCATS), Satellite Communications Systems (PD SCS).  “EBEM is [Defense Satellite Communications System] DSCS-certified, which means a lot to users. It gives them confidence that the modem is interoperable with existing military satellite equipment and won’t degrade the overall system performance,” Ng said.


PM DCATS is fielding a strategic version of the EBEM for Defense Satellite Communications System (DSCS), DoD teleport and Wideband Global SATCOM (WGS) system sites, and a tactical version for Navy shore-based sites and ships.


EBEM will increase performance, transmitting at rates up to 155 Mbps, as compared to 20 Mbps rate for the
OM-73 modem it’s replacing. Also, the EBEM’s price tag is significantly lower than the price for an OM-73.


Joint OpsBut what really sets EBEM apart, according to Ng, is EBEM’s advanced modulation and coding capabilities, which enables the modem to optimize satellite bandwidth resources. This capability “will allow users to squeeze more data into the same bandwidth, more traffic into each trunk,” said Ng.


“EBEM is more advanced and more reliable (with a mean time between failure of at least 30,000 hours) than other modems,” said Jay Hicks, chief of PM DCATS’ technical management division. “It makes better use of SATCOM resources, in terms of power and bandwidth, and its advanced capabilities will allow Net Centric warfare.”

CSS VSATOne advanced feature of EBEM, Information Throughput Adaptation (ITA), allows EBEM to mitigate atmospheric interference by automatically adjusting modulation and code rates, to preserve transmission power. “If there is rain or atmospheric interference, the EBEM is smart enough to step down coding and add more check bits, and if that doesn’t improve performance, it will step down the modulation to achieve desired performance,” Ng explained.


Also in the works, Ng added, is an enhancement called the Ethernet Service Expansion Module (ESEM), which plugs into the EBEM’s rear expansion module slot to provide an Ethernet interface to routers and support IP quality of service. This will enhance Net Centric warfare, allowing the modem to open and close trunks without dropping packets and bits and support Ethernet-based networks such as IPv4 (Internet Protocol Version 4), IPv6 (Internet Protocol Version 6), Multi-Protocol Label Switching (MPLS) and non-IP data flows. Officials expect the ESEM to be incorporated into production models of EBEM by September.

matrix switchEBEM also has its own National Security Agency (NSA)-approved internal encryption capability, and complies with Federal Information Processing Standard (FIPS) 140-2 Level 2 certification for secure encryption.


The tactical version of EBEM differs from the strategic version in that it can withstand shock and vibration, thanks to stiffeners added to the box, and also includes an antenna handover switching feature. The tactical version is currently being used by the Navy, for both shore-based and ship-based applications, “but it could be used by the Army or Marines in Humvees on the battlefield and in other tactical applications,” said Ng.