The present invention permits the transmission of variable size PDUs using a Hierarchical Sequence Numbering Space approach that supports ARQ protocols in a variable transmission rate environment. Some of the key attributes of this scheme are: (1) Support for arbitrarily variable PDU sizes; (2) Variable...http://www.google.co.uk/patents/US6317430?utm_source=gb-gplus-sharePatent US6317430 - ARQ protocol support for variable size transmission data unit sizes using a hierarchically structured sequence number approach
