摘要:
A link for transmitting digital information is time-shared between a plurality of units under the control of one of the units called the control unit. The control unit communicates with the other units by means of individually addressed signaling cells enabling it to interrogate each unit regularly as to its current status and its requirements for communication via the link and to advise it of at least one particular frame time slot for sending a response and others for sending cells. The invention also concerns units for implementing this method.
摘要:
The system includes centralizing communications equipment (4) provided with first transmitter-receiver means (5, 6) connected to at least one transmit and receive cable (3) for transmitting and receiving radio signals, which cable extends throughout the served installation. The system also includes subscriber terminal appliances (2A to 2E) located in the installation and provided with second transmitter and/or receiver means (8 to 12) for transmitting and/or receiving radio signals, which means enable the terminal appliances to communicate via the communications equipment. The communications equipment re-transmits the signals that it receives to each destination terminal appliance in the installation and, with the assistance of additional means (27 to 31), outside said installation. The subscriber terminal appliances and the centralizing communications equipment respectively include means enabling them to transmit and/or receive digitized information signals in the form of packets and via radio links.
摘要:
A wireless local area network includes a plurality of stations each comprising a data processing machine connected to a radio send-receive interface. Each data processing machine includes an interface controller for sending a message containing an address designating a destination station and for receiving messages addressed to it. The network further includes a repeater including a radio send-receive interface connected to a radiating cable passing near all the stations to receive all messages sent by the stations, to modify these messages to indicate that the message has passed through the repeater and to retransmit these messages over the radiating cable. The radio send-receive interface of each station ignores any messages not sent by the repeater. The wireless local area network finds an application in computer networking.
摘要:
The present invention relates to a method for providing services from a content server to a terminal belonging to a discontinuous coverage network, said terminal moving from a first radio coverage zone to a second radio coverage zone over a zone of non radio coverage, said discontinuous coverage network architecture comprising access controllers and radio access points each pair of access controller and radio access point defining a radio coverage zone. According to the present invention, the method comprises the step of: Sending in advance from a first access controller data in a cache memory of at least one radio access point of said second radio coverage zone, when said terminal is outside the coverage of said second radio coverage zone.
摘要:
The present invention concerns a communication device for wireless data transmission comprising: means (106, 108, 112, 114) for sending data to a receiver (104), the means for sending data being adapted to periodically send a composite signal (126), the composite signal comprising at least a first signal component using a first transmission mode and a second signal component using a second transmission mode, means (106, 108, 112, 114) for receiving data from the receiver (104), the means for receiving being adapted to receive a coverage signal (128) being indicative of a receiver reception condition regarding the composite signal, means (108) for selecting one of the at least first and second transmission modes based on the coverage signal.
摘要:
The apparatus and method pertain to generation of two receive carriers which are related to each other in quadrature. The apparatus and method employ a phase-shifter which generates one or more phase-shifted signals from a received signal. A signal selector selects a signal as a function of either a predetermined phase state associated with an initialization symbol during reception of the symbol or an estimated phase state estimated by a demodulation state on the basis of the received signal during reception of the message symbols such that the selected signal constitutes a receive carrier, which is also referred to as a reference carrier. In addition, the selected signal is stored and played back after a symbol duration before delivering the reference carrier. Finally, a second phase-shifter is used to generate a second receive carrier from the reference carrier.