# FTL Communications

## Subspace Transmission

'Subspace' refers to a plane outside of 'greyspace' with a consistent mapping of three-dimensional greyspace to subspace locations - so basically, far away places in real space are also further away in subspace.

This dimension, is, however, unique in that special signals sent in it decay non-linearly - four times the distance only results in a signal drop of half, as opposed to sixteen times. Basically - square falloff, as opposed to inverse square.

Subspace signals travel instantaneously, and wavelengths are effectively infinite. That said, there are some properties that can be both a severe limitation as well as a lifesaving boon at the same time.

- Scattering of wavelengths mean that it's possible to lock onto a particular wavelength - even if there are an infinite amount, which renders conventional frequency scanning impossible.
- **Strong** signal encryption and negotiation protocols must be utilized to prevent an adversary from listening in after a sufficient amount of time spent 'locking onto' a nearby signal, as well as from jamming the signal with focused jamming - which is far stronger than 'broadcast' jamming.
- Signals can be potentially scattered in a way that turns them into 'broadcast' signals with a linear drop, as opposed to the usual focused square drop of communications signals.
- This can be used for distress beacons where one wishes to transmit on non-known bands as well, as well as for jamming by having said signals interfere with transreceivers operating in the vicinity.
- The transmission plane is inherently noisy. Signals are generally sent in tandem across multiple negotiated wavelengths to artificially speed up transmission rates, as a signal link can become throttled from cycling as fast as conventional electronics would allow.
- Even with the square drop of signals in subspace as opposed to the inverse square drop of electromagnetic waves in realspace, astronomical distances make transmission and reception power a real issue for smaller ships and installations.
- Most sectors have relay infrastructure set up to make constant communications viable from lower power vessels and bases. Nanotrasen (and many other corporations) specifically tend to carry complex relay and routing hardware with their fleets - normally placed on an utility ship or flagship - to boost networking capabilities of nearby vessels.

Subspace communications generally require a great deal of sensitive machinery working together in tandem to receive, de-noise, route, and re-transmit as necessary. Such machine rooms normally require electromagnetic shielding and isolation from surrounding areas, as electromagnetic interference tends to be amplified by the ansible's machinery in their process of tunneling into subspace.

## Quantum Particle Decoherence

While subspace communications is the most convenient form of communications, there is a form of communications discovered even prior to subspace by most FTL civilizations.

While quantum entanglement is *normally* unusable as a form of communications, through the use of special machinery, particles may be forced to decohere into a specific spin - which allows the receiving side to measure their copy of the particle as being the opposite spin.

Furthermore, this decoherence can be measured by special instruments - as to know when to perform the 'read' operation, as to not cause the entanglement to decay early. This makes it viable as a 'wake' signal for transmitters.

This, however, is even more difficult to utilize than subspace transmissions. Particles can obviously not be reused - which means that particles must be produced with a high-end particle accelerator system, and then immediately suspended in a special metamaterial to prevent outside observation until necessary.

- The particle generation process inherently has noise to it - standard generation and transmission systems require matching 'cartridges', and resend data anywhere from seven to ten times for a single bit, to ensure proper reception.
- The generated particle pairs must be physically shipped to the destination. Furthermore, the generation itself is expensive to perform given the *insane* precision required. This results in production facilities being coveted - and restricts this system to critical applications where subspace transmission may not be directly used.
- This is often thus used for transmission of small in volume, but highly sensitive data - as well as for re-negotiation systems for subspace ansibles.

As a small consolence for the usage of QPD-based communications, the infrastructure required to send and receive communications tends to be small, compact, and require *very* little power - instead being expensive in the precision manufacture requried to create such transreceivers.

## Hybrid Systems

- While rare with the development of subspace beacon stations, it's not unheard of remote observation outposts to be sent coherent particles via drone every so often, and simply rely on them to know when to power up their subspace transmitters. Given their remote location and low profile, they would not have the available power to consistently power on their transmitters.
- This is also a viable strategy to prevent frequency sniffing and location tracking, by only powering on transmissions when one knows there is a need to communicate.