Rlc/mac protocol

摘要

In the LAPDm a short message service is implemented by pre-emption of every second signalling message when there is a short mesa sage to be sent. Same pre-emption mechanism is also needed when the RLC/MAC protocol is used on the data link layer instead of the LAPDm. The mechanism is provided by defining at least two different identities to be used with frames transmitted on the signalling channel; and pre-empting frames on the MAC at least on the basis of the identity relating to a frame. The identities are preferably identified on the basis of the signalling radio bearer of the frame.