Abstract: An optical amplifier device intended for WDM light signals comprises a preamplifier (3) and a power amplifier (11) of the optical fiber amplifier type, which are connected in series and have gain curves dependent on the wavelength. A controllable attenuator (5) is connected between the amplifiers (3 and 11) and is controlled by a control device (7). The signal input to the preamplifier (3) has a low power and is amplified to provide an output signal where the signals of the input channels have been amplified with different gains. The input signal of the power amplifier (11) then has a larger power resulting in a gain characteristic different from that of the preamplifier (3). By adapting the attenuation of the attenuator (5) for variations in the input signal the gain characteristic of the power amplifier (11) can be set so that the signal output from the amplifier device has a spectral dependence that is the same as the original spectral dependence obtained without variations.

Abstract: A method and arrangement according to the invention selects the modulation and coding scheme MCS on a non-power-controlled downlink shared channel (DSCH) based on the amount of transmit power allocated to the downlink dedicated physical channel (DPCH) corresponding to the mobile station currently using the DSCH. Each mobile station in the system that takes part in sharing the DSCH has access to one associated DPCH. The DSCH is shared between the users in some way, e.g. in a time division fashion, wherein one user at a time uses the resources, and is not power controlled by any of the users. In a preferred embodiment, the procedure of selecting an appropriate modulation and coding scheme MCS for the DSCH as a function of the power level on the DPCH associated with the user currently using the DSCH is repeated each time the transmitted power of the associated DPCH changes.

Abstract: The transmit power of a base station transmission to a mobile station is advantageously controlled. The base station receives a signal from the mobile station and determines a signal-to-interference ratio (SIR) associated with the received signal. The base station controls its transmit power to the mobile station using the determined SIR value in conjunction with a transmit power control command received from the mobile station. When the mobile station is in the process of a soft handover involving two or more base stations, each of those base stations determines an SIR value associated with a signal received from the mobile station. Moreover, each of the base stations controls its respective power using both the power control command received from the mobile station and the SIR determined by that base station.

Abstract: An add/drop (7) node for an optical fiber network of WDM type has preamplifiers (19, 21) connected to the input fibers (3, 11). Part of the incoming signal power is tapped off by means of drop couplers or splitters (47, 49) and the tapped-off power is provided to a demultiplexer (51) where WDM information channels to be extracted from the network in the node are separated from each other and then fed to opto-electrical receivers (15). WDM information channels to be added in the node from electro-optical transmitters (17) are first combined in a multiplexer (61), the resulting signal being provided to add couplers (57, 59) to which also the signals incoming to the node are provided so that a combined signal is obtained for transmission to the opposite side of the node (7). Channels are thus added in the node to channels passing substantially ininterrupedly through the node.