Description of a complete multi-carrier spread spectrum transmission chain for robust and discrete tactical communications

Multi-carrier spread spectrum (MC-SS) techniques have been widely studied for the last few years. This paper describes a complete transmission chain based on an MC-SS technique for tactical communications. The constraints on the waveform are discreteness and robustness to frequency selective channels and jammers. Therefore, polyphase filtering is used in order to meet these requirements. Besides, the system must be able to provide a high data rate for different tactical configurations. The paper presents the features of these configurations (filtering, modulation, coding, spreading), and the algorithms used for time synchronization and for the phase and frequency estimations. Then performance obtained over an AWGN channel (with-and without a power amplifier), over a Rummler channel or with jammers is presented. Finally, complexity estimation reveals that the implementation of such a modem is technically achievable. The study shows that the modem is able to resist to multipath channels, and that encoding and filtering allows it to resist a powerful jammer.