A New Multiple Access Scheme to Ensure Security in CDMA-based Wireless LANs

| Wireless medium is inherently insecure due to its broadcast characteristics. As wireless communications become more prevalent and utilize the radio channel for transmission of critical information, the concern for security becomes an important issue. In this paper a new CDMA-based multiple access scheme for wireless LANs is proposed to provide enhanced security. Although most of the e orts in providing security have been content with letting the attacker know which bits have been sent, the newly proposed scheme provides another layer of protection by making acquisition of the spread spectrum signals di cult for unintended receivers. The new multiple access scheme, DSS (Double Sequence Scheme), utilizes not one LFSR (Linear Feedback Shift Register) PN (pseudo-random number) generator, but two LFSR PN generators of register length R and S to create a chip sequence that is extremely resistant to attacks. The number of calculations necessary for the attacker to exhaustively guess future chip sequences is analyzed and performance characteristics of the security-enhanced slotted CDMA protocol such as throughput, delay, and cell error rates are examined. Keywords|Security, Wireless, CDMA, LFSR