Abstract: In a method of communicating messages between a transmitter and receiver, wherein each message is sent in sequence and includes a sequence number. An expected sequence number, which is stored in the receiver, is incremented upon receipt of a message. The received sequence number in the message is decoded and compared to the incremented expected sequence number. If the numbers match the message is further decoded.

Abstract: In the UMTS, semi-static uplink and downlink connection parameters relating to the frequently-used services of voice, fax and web browsing are intermittently broadcast to mobile user equipment (20) which stores the parameters. When a mobile requests (30) one of those services, the relevant dynamic parameters are sent (32) over the radio interface and the mobile is asked whether it has in its store the relevant parameters for the requested service; if so (34), the call is set up; if not (36), the semi-static parameters relevant to the requested service are sent (38) to the user equipment. Considerable saving of radio resource results.

Abstract: In a UTRAN operating time division duplexing, one time slot 22(11) in each frame is maintained in a no-transmit condition, all preceding time slots 22(1) to 22(10) being uplink time slots and all succeeding time slots 22(12) to 22(15) being down link time slots (or vice versa). Cell size is markedly increased.