A communication system in which signalling information and other traffic such as user information between a mobile station and a base station, or between a first mobile station and a second mobile station is transmitted in variable bit-length messages. The transmitter includes in its message a length indication message for indicating to the recipient the length of the message that is being transmitted. The length indication message has a basic meaning in units of octets but is multiplied in the receiver by a multiplying factor which is dependent upon the modulation method used for the transmission to determine the true length of the message.
