Abstract: The safe method of handing over a call set up with a mobile station (M) comprise the following cyclic steps:a following base station (B(n)) receives (ET3) UP data (DM) of the call in a following channel (CH2), which UP data is transmitted by the mobile station (M) in a current channel (CH1) to a current base station;the DOWN data of the call is transmitted (ET5) for a given duration (T) simultaneously both over said current channel (CH1) and over said following channel (CH2), from the current base station (B(n-1)) and from the following base station (B(n)) respectively as soon (ET4) as the propagation time difference (TA) between the respective instants at which said UP data is received by said current channel (CH1) and by said following channel (CH2) is less than a first predetermined threshold (S); andon expiry of said given duration (T), releasing (ET6, LIB) said call in said current channel, and validating said call in the following channel (CH2) as a new current channel.

Abstract: A method of performing cellular digital radiocommunications in a TDMA system implemented within a network of geographical cells through which mobile stations (SM1 to SM22) travel, a base station being associated with each of the cells, a mobile station communicating via the base station that is associated with the cell in which the mobile station is located. Each each of the frames in the up transmission direction, from the mobile stations to the base station, contain at least one shared time slot (IT6) which is allocated to at least two distinct mobile stations (SM7 to SM22). For each shared time slot (IT6), the system has a list (31) of the active mobile stations, an active mobile station being a mobile station to which the shared time slot is allocated, and which satisfies at least one predetermined selection criterion.

Abstract: A mobile radio system conveys frames between at least one mobile station and at least one base station, each frame comprising N time slots, a burst of data being transmitted in each time slot, and each time slot being associated with a separate call between a mobile station and a base station. For each call over a transmission channel, the quality of the transmission channel is analyzed and, on the, basis thereof, a selection is made between first and second modes of transmission. In the first mode of transmission data to be transmitted is organized in first blocks obtained by a first encoding of source blocks, each of the first blocks has a size greater than the content of (P-1) bursts, where P is an even number at least equal to 2, and the data of the same first block is distributed between at least P bursts.

Abstract: A source sequence including N data elements is interleaved to deliver an interleaved sequence according to a method which includes at least one interleaving step associating a data element of index j in the interleaved sequence with a data element of index i in the source sequence, where:j=(a.multidot.i+b) (modulo N)+1, 1.ltoreq.i.ltoreq.N and 1.ltoreq.j.ltoreq.N;a is a predetermined integer relatively prime with N and such that 2.ltoreq.a.ltoreq.N-1; andb is a predetermined integer such that 0.ltoreq.b.ltoreq.N-1.

Abstract: In a method of determining, in a cellular mobile radio system with more than one type of cell, which type of cell a mobile station is accessing, the management network of the system sends to the mobile station a signalling message (recognition message) in the form of a sinusoid whose frequency (recognition frequency) differs from a reference frequency known to or determinable by the mobile station. The difference, optionally a null difference, between the reference frequency and the recognition frequency is characteristic of the cell type. The mobile station determines the recognition frequency. The mobile station then determines the difference between the reference frequency and the recognition frequency. The mobile station then determines the cell type from this difference.