Performance of high rate Link-22 operation obtained by using quadrature amplitude modulation (QAM)

Abstract

As part of its Improved Link-11 program, NATO is currently developing the Link-22 system for the dissemination of F-series messages over tactical voice band HF links. Link-22 uses a TDMA protocol with a 112.5 ms slot time as currently specified, Link-22 has the capability to transmit from 2 to 6 F-series messages per TDMA slot. We present a method for extending this figure to 16. Quadrature amplitude modulation is used to provide the increased channel bit rates that are required. Simulation and field test results are presented which compare the performance of the current and extended rate systems.