Patent GB-1522101-A (GB)
Title: Relay station for a radiocommunication network and corresponding network
IPC: H04B7/14
Filed: 1976-02-11
Abstract: 1522101 Relaying in radio communication THOMSON-CSF 11 Feb 1976 [14 Feb 1975] 5463/76 Heading H4L In a radio communication system, a relay station comprises a decoding circuit receiving control signals, and establishing at the relay station, in response thereto, either, a state in which autoretransmission of received signals takes place, or a blocked state in which no transmission takes place pending further control signals, or a third state in which either (i) an "available" signal is recurrently transmitted at a timing enabling the identity of the available relay station to be determined, Fig. 1, or (ii) an auto-retransmission state existing only for a time slot enabling identification of the relay station Fig. 4 (not shown), and during which a request for connection can be transmitted via the relay station to a central station. First embodiment, Fig. 1.-The auto-retransmission state is established by a baseband binary signal from the central station, passing via receiver 112 and converter 10 to the decoding circuit 5 to set bistable 41 enabling switch 16 and transmitter 2. The blocked state is established by a signal from the central station to reset bistables 41 and 43. The state (i) is established, under the control of a central station signal, by setting bistable 43, enabling signal generator 6 to provide an availability signal, for transmission at an epoch determined by the attainment of counter 9; reset to zero at timing intervals; of a predetermined count, unique to the relay station. When the relay station is in such an available state, a request for connection from a terminal station may be used to replace the available, by a blocked, state, the loss of reception of the available signal at the central station indicating the presence, at the particular relay station, of the request. Second embodiment, Fig. 4 (not shown). The state (ii) is established by setting bistable (103) enabling the re-transmission mode for a duration equal to the time counter (109) takes to count to a predetermined value, whence the bistable is reset. A plurality of relay stations associated with a central station assume the state (ii) in non- overlapping sequence. A signal from the decoding circuit (5), at (52) resets both bistables to establish the blocked state, the auto-retransmission state being obtained by setting bistable (41). In use, for each available relay station a sequence of states, (i); separated by the blocked state, exists, the existences of state (i) providing opportunity for requests for connection to pass to the central station. Central station, Fig. 3 (not shown).-The station is controlled by mini-, or micro-computer (74) controlling the transmission, at a first carrier frequency, of either messages from unit (82), or control signals destined for the relay station decoding circuits. The computer also controls reception, separating, from the received signals at a second carrier frequency, message signals, or availability signals from the relay stations. Terminal station, Fig. 2 (not shown).-If the transmitter-receiver (25) detects the existence of state (i) of the associated relay station, a request for connection signal, from generator (31), may be transmitted, the resultant cessation of availability in the relay station, Fig. 4, causing the relay station to be set to re-transmit a message from unit (33). All other relay stations are meanwhile blocked, and, at cessation of communication, all the relay stations take the state (i). A common carrier frequency may be shared by some paths passing via distinct relay stations. The transmitters and receivers are connected to couplers, or aerials. At the central station, a plurality of transmitters and receivers may be associated with corresponding directional aerials.