Recommendations for the implementation of a practical spread spectrum communication system robust against smart jamming

Abstract

Spread spectrum transmission is presented as an anti-jamming alternative for ITS. In this article, the vulnerability of this technology to eavesdropping, and consequently jamming, is highlighted. Applying an iterative message-passing algorithm, it is possible to estimate the initial state of an m-sequence or Gold sequence generator, and hence be able to generate the same spreading sequence as the target user. As a result, an attacker can generate a valid jamming signal which will be difficult to detect at the physical layer. The practicability and efficiency of this attack depend on some properties of these sequences: number and smallest degree of low weight parity check equations. These two properties are analyzed and exploited to provide some recommendations for the implementation of a practical spread spectrum communication system. Eventually, simulation results show the feasibility of this attack.