Inria Institut National De Recherche En Informatique Et En Automatique

Paul Muhlethaler

Philippe Jacquet

A system for transmitting messages comprises stations (S) having an operating system ( ), a &ldquo;network&rdquo; stage ( ) for processing and generating messages in a first format, a communication card ( ) for exchanging messages in a second format with a network, a &ldquo;driver&rdquo; stage ( ) for putting the messages received from the card ( ) or the network stage ( ) in the first format or second format and transmitting them to the network stage ( ) or to said card ( ). The stations further comprise a management stage ( ) coupled to the operating system ( ) and adapted to intercept messages in the first format which are to be exchanged by the network stage and the driver stage so as to analyse the information which they contain and decide to continue their transmission, subject to any required processing, and/or adapted to generate messages in the second format, intended for the stations of the network, when a chosen condition is met.

System for transmitting messages to improved stations, and corresponding processing

Connected relay stations of a network each include a network number, a clock ( ) defining a local reference time, a module ( ) for transmitting/receiving messages on a frequency varying according to a selected time-division scheme defined relative to the local reference time, and a control module ( ) for the messages. The control module of a synchronising relay station (SH) forms synchronisation messages including its network number, a common frequency, its time-division evolution scheme and a common reference time, for the transmission thereof. In addition, each relay station (SH) includes a synchronisation module ( ) capable of extracting the information contained in a synchronisation message received bearing a common network number, in order, on the one hand, to readjust the local reference time defined by the clock ( ) to the common reference time and, on the other hand, to provide the transmitting/receiving module ( ) with the common frequency extracted and its time-division scheme, such that the relay station is frequency-synchronised with the synchronising station and in turn becomes a synchronising station.

System for the transmission of data to synchronised relay stations and corresponding process

A connection device connects a radio network and a cabled network communicating respectively by way of messages encapsulated according to radio and cable protocols, and includes a storage module containing a routing table, and a processing module for managing exchanges of data as a function of the routing table. The processing module includes a management module capable on the one hand of disencapsulating a message received from the radio network, in order to extract routing information therefrom and then to compare this information with the routing table in order to choose at least one re-sending network for the message, and on the other hand of re-encapsulating the message in the radio network format or according to a mixed radio format, having radio and cable capsules, depending on whether the re-sending network chosen is the radio network or the cabled network, with a view to re-sending it in the chosen re-sending network segment.

Method and apparatus for connecting network segments

A data processing station wherein a network interface monitors the transmission channel and generates event signals, e.g. &ldquo;transmission start&rdquo; &ldquo;collision detected&rdquo; and &ldquo;channel back to vacant condition&rdquo;. If a collision occurs in local transmission, transmission is maintained with a collision indication for at least one period before being cut off. An observation register receives the event signals and responds by generating a channel observation signal which may be &ldquo;transmission OK&rdquo; &ldquo;collision slot&rdquo; and &ldquo;vacant slot&rdquo;. When transmission of a fresh data packet is requested, a first transmission may or may not be attempted (normal mode) depending on the condition of the observation register. If the attempt is unsuccessful (transmission refused or collision), a suitably reset mechanism for incrementing/decrementing a common integer determines the right to transmit, so that the response to a request for the transmission of a fresh data packet is made regardless of the channel's operating record, upstream from the last normal mode to be executed.

Data transmission device for random access network, with improved collision resolution, and corresponding method

A data transmission installation includes at least two data processing tenals(Pa,Pb), each equipped with a network interface(Ia,Ib) fro transmitting messages on request, and collecting received messages, a transmission/reception management device(ARC) giving instructions confirming transmission or reception, a test unit for defining a recognized collision, and a unit for resolving collisions, following a recognized collision condition. Each of the data processing terminals includes a multi-directional radio transmission/reception device controlled in accordance with the confirming instructions fro the transmission of messages to be exchanged. In response at least to the start of an instruction confirming transmission, the radio transmission/reception device operates in rapidly alternating transmission/reception, according to a pattern chosen in order to be peculiar to the data processing terminal. The test unit is configured to recognize a collision if a signal of a level greater than a first level threshold is received during a substantial part of at least one silence in the rapidly alternating transmission/reception.

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Maisons Laffite, France

Paul Muhlethaler