Intervehicle communication and ranging system using code-hopping spread spectrum technique

For safe driving in vehicles, an understanding of the surroundings by radar and information exchange with nearby vehicles by communication are considered to be necessary. We propose an intervehicle communication and ranging system that uses the spread spectrum system known as a boomerang transmission system to simultaneously communicate and range by carrying information on the radar waves. Pseudo‐noise (PN) codes are used in a spread spectrum system, but since the number is limited, assigning a unique PN code to all of the vehicles is difficult, and codes must be reused. When multiple terminals temporarily use the same code at the same location because of the hidden terminal problem, severe interference occurs and the reliability of the communication and ranging is greatly damaged. Therefore, in this paper, a boomerang transmission system is proposed where code hopping eases the limitation on the number by switching multiple PN codes. Simulations verify the communication and ranging capabilities even when the desired wave and the interference wave use the same PN code sets for three systems: the slow‐code‐hopping boomerang transmission system (SCH), the fast‐code‐hopping boomerang transmission system (FCH), and the adaptive‐code‐hopping boomerang transmission system (ACH) with code collision avoidance. © 2005 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 88(5): 50–60, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.20078