1. A method of de-fragmenting a transmission sequence to transmit a structured document prior to transmission of the structured document, the structured document comprising sub-documents with related relevance weightings being modelled as nodes of a graph, the context linkages between different sub-documents being modelled as arcs of the graph, and the transmission sequence being modelled as an ordered set of nodes, comprising the steps: selecting the node with highest relevance weighting as next node of a de-fragmented transmission sequence; determining a distance measure from the selected node to nodes of the transmission sequence which are not assigned to the de-fragmented transmission sequence using the graph modelling of the structured document and shortest path metrics; adjusting relevance weightings for nodes which are not assigned to the de-fragmented transmission sequence as a function of the related distance measure; recursively repeating the previous steps until all nodes of the transmission sequence are processed.