New scheme for underwater acoustically wireless transmission using direct sequence code division multiple access in MIMO systems

Abstract

This paper proposes a new technique based on Direct Sequence Code Division Multiple Access for underwater acoustically wireless transmission with excessive transmission rate. Environment of subsea is challenging for wireless communication because the medium in which waves are propagating is not air. In fact, it is propagated through fractions of water having different densities. Finding out various techniques for multipath access targeting the physical layer of Acoustic Sensor Networks is indeed necessary. The recent approaches have suggested that coded modulation techniques with exploited diversity are highly preferred in order to enhance the dependability of the acoustic link in different multipath channels. The proposed technique divides the channel into sub ones and transmits information via those sub channels. In variety-spectrum, a signal in a bandwidth is unfold within frequency domain and broad bandwidth. Experimental results show that Bit Error Rate (BER) of this method is better than that of channel equalization in the respective systems.