DIRECT MAPPING OVSF-BASED TRANSMISSION SCHEME FOR UNDERWATER ACOUSTIC MULTIMEDIA COMMUNICATION

Underwater communication networks are currently being developed for use in underwater control systems, underwater telemetry systems, and underwater image transmission systems. The transmission bandwidth and transmission rates of an underwater communication system are low, and its transmission delay is high. In this paper, we propose a direct mapping orthogonal variable spreading factor (OVSF)-based transmission system for underwater acoustic multimedia communication. An important feature of this transport architecture is that a power assignment mechanism, an OVSF scheme, a direct mapping strategy, an unequal error protection scheme, and adaptive modulation are employed for transmitting messages that can tolerate various bit error rates. For confirming the effectiveness of this transport architecture, we perform a simulation using measured data of a G.729 audio signal and a JPEG2000 image signal. The simulation results show that the proposed system can achieve maximum transmission data rates or minimum transmission power. In addition, the OVSF-based transport architecture is a feasible platform in underwater acoustic multimedia communication.