SPECIAL OPERATIONS FORCES TACTICAL ASSURED CONNECTIVITY SYSTEM

The special-operations community has a long-standing requirement for sending and receiving large amounts of data, but its capability has been limited by the amount of data a tactical radio can send and receive. To address the issue, the United States Special Operations Command developed a family of systems under a program called the Special Operations Forces Tactical Assured Connectivity System, or SOFTACS.

SOFTACS is intended to provide large, medium and small systems that can support group-, battalion-, company- or team-level operators with a high-capacity terminal capable of sending and receiving traffic on secure and nonsecure networks. In the past, however, a terminal small enough for a team to use would not provide the required capability, and a terminal with sufficient throughput was too large for the team to deploy effectively. But during the past two years, technological advances have allowed SOFTACS to develop a relatively small, high- volume terminal that can be installed, operated and maintained by Soldiers in special- operations forces, or SOF.

Within the SOFTACS family, the SOF Deployable Node-Light, or SDN-L, is the primary system designed to support operators at the team level. SDN-L has evolved through several stages in order to meet the operator s needs. The earliest versions, the SDN-L Vl and V2, used the INMARSAT worldwide satellite communications system and transmitted up to 64 kilobits per second, or Kbps. Next came the V3A, which also used INMARSAT and was capable of transmitting data at 492 Kbps. But while these versions were functional and easily deployable, their throughput was still small.

The next evolution was the SDN-L VX, currently in use in Afghanistan and Iraq, which has a terminal capable of communicating in the Ku microwave band. The VX has a much greater throughput than the V3A: it can transmit data at up to 2 Mbps and simultaneously receive up to 4 Mbps.

The VX is significantly larger than any of the previous SDN-L systems, however, requiring five carry- on-sized transit cases for deployment rather than the single case used by the earlier versions. VX is also limited to transmitting in the Ku band. Further development has produced a more versatile terminal that a team could easily deploy and carry around the battlefield.

The next generation of SDN-L is the V3b. Smaller than the VX, the V3b requires only two transit cases for deployment, yet it provides performance nearly equal to that of the VX and in some cases exceeds the VXs capabilities. While the V3bs default configuration is for operation in the Ku band, it is capable of operating in the Ka and X microwave bands. Operating the V3b in the multiple-band capability requires additional cases for deployment, because each band requires a separate satellite dish.

The V3b can send data at up to 1 Mbps and simultaneously receive at up to 4 Mbps in the Ku band. If equipped with an X-band satellite dish, it can send and receive at up to 4 Mbps. The V3b supports traffic on the Nonsecure Internet Protocol Network, Secure Internet Protocol Network and Joint Worldwide Intelligence Communications System, and it can support up to four users simultaneously. The V3bs cost is roughly two-thirds that of a VX terminal.

Less than five years ago, the ability to send and receive 1 Mbps or more of data in a man-packable system was not possible, but by the end of 20 1 1 it will bea reality for SOF Soldiers. As technology progresses, the SDN-L V3b may be replaced by lighter, more capable systems, but for now, it is one of many cutting- edge systems that will enable SOF operators to perform their missions more effectively than ever before.