Abstract: According to method and apparatus for communication in a cellular TDMA mobile radio communication system with channel hopping, base and mobile stations transmit radio signal bursts in time slots of a plurality of radio channels in accordance with channel hopping schemes. All of the schemes used by a base and mobile stations in a cell are free from coincidence on any radio channel with any other of the schemes used for transmission within the same cell. A scheme used by a mobile station in one cell occasionally coincides on a radio channel with a scheme used by a mobile station in another cell. The major part of every channel shifting scheme used by a mobile station in a cell is free from coincidence on any radio channel with the major part of any channel hopping scheme used by a mobile station in another cell.

Abstract: A method of detecting the identity of a radio channel and to ascertain whether the channel is a control channel or a traffic channel, in conjunction with convolution decoding in a mobile radio receiver. Channel identification is effected without such complete decoding. Part of a data block is decoded in accordance with the Viterbi algorithm as though the block represented a control channel. If the metric obtained after a given number of nodes is smaller than a given number of threshold values, the channel is considered to be a control channel and is thereafter decoded as such a channel. If the metric is greater than the threshold value, the channel is decoded as a speech channel.

Abstract: A method of synchronizing a baseband demodulator in a radio receiver, which may be stationary or mobile. The demodulator is a phase-shift demodulator and detects a baseband signal incoming from a sampling A/D-converter in the receiver. The baseband signal is transmitted from a radio transmitter in the form of bursts, in time slots in accordance with the TDMA-principle. One time slot, in addition to the data word, also includes in a known manner a synchronization part which has a given, fixed bit pattern. Prior to demodulation in the baseband demodulator, differential correlation of the received baseband signal is effected with the known synchronization pattern, wherein a time-dependent correlation function is obtained. The absolute magnitude of the maximum value is calculated and the corresponding time position for this maximum value is detected, which denotes the time position of the synchronization part of the received baseband signal.