A star topology to improve CAN performance

Abstract

Because of the particular medium access technique they adopt, CAN networks suffer from an intrinsic drawback which severely limits the maximum bus length allowed at high bit rates. In this paper a new proposal is introduced, which is based on a star topology and permits to enlarge the CAN network extension more than ten times. In the proposed scheme, a star coupler takes part actively in the arbitration phase by disabling on-the-fly all the nodes which lose the contention. The new mechanism shows a behaviour which is very similar to CAN, thus a satisfactory degree of compatibility with the original protocol can be preserved.