Abstract: There is provided an intra-realm AAA (authentication, authorization and accounting) fallback mechanism, wherein the single global realm may be divided in one or more sub-realms. The thus presented mechanism exemplarily comprises detecting a failure of an authentication server serving at least one authentication client within a first sub-realm of a single-realm authentication system, and routing authentication messages of the at least one authentication client to a fallback authentication server within a second sub-realm of the single-realm authentication system, wherein routing may exemplarily comprise sub-realm based source routing.

Abstract: Transmitting physical signals precoded at the physical layer, and transmitting via a physical channel precoded at the physical layer decoding information for use in physical layer decoding of said physical signals; wherein said decoding information is incorporated into one or more data units at a layer higher than the physical layer. Transmitting in a single sub-frame one or more physical reference signals for use in physical layer decoding of a physical channel in a plurality of sub-frames.