Abstract: The invention relates to an approximation of a DCT and a quantization which are to be applied subsequently to digital data for compression of this digital data. In order to improve the transform, it is proposed to simplify a predetermined transform matrix to require less operations when applied to digital data. In addition, elements of the simplified transform matrix constituting irrational numbers are approximated by rational numbers. These measures are compensated by extending a predetermined quantization to include the operations which were removed in the simplification of the predetermined transform matrix. The included operations are further adjusted to compensate for the approximation of elements of the simplified transform matrix by rational numbers. If the simplified transform matrix and the extended quantization are used as basis for implementation, a fast transform with a good resulting quality can be achieved.

Abstract: The invention relates to a method of ciphering data transmission in a radio system, and to a user equipment using the method, and to a radio network subsystem using the method. The method includes the steps of: (602) generating a ciphering key; (604A) producing a ciphering mask in a ciphering algorithm using the ciphering key as an input parameter; (604B) using a logical channel specific parameter or a transport channel specific parameter as an additional input parameter to the ciphering algorithm; and (606) producing ciphered data by applying the ciphering mask to plain data.

Abstract: The invention relates to a telecommunications process with time division multiple access (TDMA) between a first and a second station, in which process one station transmits and the other receives in at least one predetermined time slot of a frame. In this process, the carrier frequency is changed over in this time slot (Z3) from frame (R1) to frame (R2), in order, in this way, to be able to set up a plurality of transmission channels, using only one time slot. This changing over of the carrier frequency is terminated given fulfilment of an abort criterion.

Abstract: An antenna assembly comprises an elongate antenna element (11) mounted in a support (5) and movable between a retracted position and an extended position. A helical antenna element (12) in electrical contact with the helical element is carried at one end of the elongate element. The coupling between the feed point and the antenna in the retracted and extended positions allow the same matching circuitry to be used in both conditions. The invention provides a compact and convenient dual antenna arrangement ideally suited for use in a portable cellular radio telephone.