Applying spread spectrum technique for transmitting extra bits over AWGN channel

Abstract

This paper describes an encoding scheme based on direct sequence spread spectrum technique for conveying some extra bits in a communication channel. In the encoding process, a small amount of information is added into the original transmitted signal to generate the output signal for transmission, and the user at the receiver end is able to obtain both contents. In the decoding process, the added extra bits are first extracted from the received signal, and then used to recover the original signal. The scheme was examined by simulation method and its performance was measured. Error control codes were applied to the extra bits before the encoding process so that the scheme's performance can be significantly improved. The scheme was also examined by transmitting the data through an AWGN channel to observe its performance when implemented in general applications. With the proposed scheme, the existing allocated bandwidth in the broadcast channel can be utilized in a more efficient way.