Patent ID: 9215726
Filing Date: 2015-12-15
Classification: H04B,H04W

Abstract:
1. A method for ionospheric Radio Frequency (RF) transmission of messages in High Frequency (HF) bands to remote receiving devices, the method comprising: receiving a message for transmission to a remote receiving device over a frequency in an ionospheric HF frequency band; encoding the received message into a format derived to effect message latency; determining transmission parameters for transmission of the encoded message in the ionospheric HF frequency band based at least on (a) message latency and on (b) a predefined channel bandwidth; and transmitting the encoded message in the ionospheric HF frequency band according to the determined transmission parameters to the remote receiving device, wherein: the determined transmission parameters include at least one of a carrier frequency, a modulation type, a transmission power, a sampling rate, and a buffer size; the message latency includes a delay component that is based on a propagation delay to the remote receiving device and a size component that is based on a size of the encoded message; the predefined channel bandwidth is based on a spectral emission limit for individual channels in the ionospheric HF frequency band; a contribution to the propagation delay, τ, is calculated according to: and wherein c is the speed of light, n is a number of hops, d is a length of a hop, Δ is an elevation angle, and Ro is the radius of the earth.