an improved method of framing data packets in a direct sequence spread spectrum system that uses one pseudo - noise code to frame the packet with a start - of - packet and end - of - packet indicator , and a different pn - code to encode the data payload . furthermore , the sop is represented by the framing pn - code , and the eop is represented by the inverse of the framing pn - code . this method creates a robust framing system that enables a dsss system to operate with a low threshold of detection , thus maximizing transmission range even in noisy environments . additionally , the pn - code used for the sop and eop indicators can be used to indicate an acknowledgement response .