You know how in old war movies soldiers “synchronized watches” so everyone in the mission knew exactly when to do their part and could be sure others had done theirs first? (Before ubiquitous cell phones anyway.) If you’re over 40, go watch The Dirty Dozen for the thousandth time; otherwise, see Back to the Future.
I mention that because today we released Version 1.2 of the Digital IF Interoperability Standard with the addition of synchronized timing and flow control. This sounds like one of those down-in-the-weeds technical things that gearheads like me love, but it also has powerful implications for the business and missions of space networks. Here’s why.
Like good soldiers and time-traveling DeLoreans, each network element must know when to do its part. Today, most devices rely on a single gateway time source with synching across the network through modems. While this works, it is inefficient for many use cases, especially in popular and growing markets such as air mobility.
Generally, you want timing defined at the earliest moment possible in your downlink signals, but at the latest possible time for transmitted signals, such as TDMA. DIFI 1.2 enables this flexibility by providing an open standard that allows for synch and flow control to and from the digitizer or other devices in the service chain. This means timing can now be referenced from the network edge through the Digital IF stream to the rest of the equipment in the local service chain.
In airborne connectivity, for example, there is the unique challenge that L-Band communications signals cannot be allowed to interfere with the plane’s altimeters, which also use L-Band. That mandates complicated routing through heavy, shielded, expensive coax cable causing a complex integration and SWAP problem. In addition, any imperfections in the cable or connections will cause leakage and interference. Digital IF data, on the other hand, can run over standard ethernet cables and, potentially, over the aircraft’s existing network. The sync and flow control allows the DIFI functions on the aircraft to be synced to the digitizer, thus eliminating the need to provide a timing source to each device in the chain.
There are many other use cases where greater flexibility in timing control brings huge advantages over hardware IF/RF systems where timing must be defined at the modem since analog signals cannot be time stamped.
Just like you can’t travel in time without plutonium for your flux capacitor.
Version 1.2 is openly available to all and can be downloaded free of charge.
Read more from DIFI Consortium.
