Abstract: In a shared medium communication system (100), a common measure for avoiding collisions of application data is a request grant mechanism. Secondary stations (104) contending for upstream bandwidth send requests on a shared medium (106) that are each answered by a grant (110) from the primary station (102). The efficiency of such a system can be improved if at least two access requests are merged into a multi-request (108).

Abstract: A broadcast system for broadcasting data streams includes a hierarchical network of data distributors starting from one central distributor (110) through at least one layer of intermediate distributors (120, 130, 140) to a plurality of broadcast receivers (150). Data streams are broadcast through downstream channels (160) of the network to the plurality of broadcast receivers. At least one distributor hierarchically below the central distributor is operative to insert broadcast data in at least one up-stream channel (170) of the network towards the central distributor. The central distributor is arranged to re-distribute broadcast data received via at least one up-stream channel through at least one downstream channel of the network.

Abstract: A broadcast system 100 for broadcasting at least one title using a near-video-on-demand broadcasting protocol includes a plurality of broadcast receivers 150. A hierarchical network of data distributors starts from a central distributor 110 through at least one layer of intermediate distributors 120, 130, 140 to the broadcast receivers for broadcasting the title as a sequence of data blocks. A least one filter controller 180 receives requests from broadcast receivers for the supply of the title and controls at least one intermediate distributor to filter out data blocks of the title that have not been requested by receivers hierarchically below the intermediate distributor.