Nokia Corporation

Harri Lahti

Marko Mikael Torvinen

Esa Torma

The object of the invention is to introduce an advanced method and arrangement for changing parallel data transmission connections in an assured data transmission link. According to the method of the invention, the transmission path to be received is changed, prior to the passage of errors, and the data transmission of the link remains free of errors, in case even one of the transmission paths transmits the data as error-free, even if errors occur in other paths. The error-free quality of the link is maintained also when error-free and erroneous data transmission paths are suddenly exchanged. This is realised by calculating, in the parallel outdoor units (OU) located in succession to the common indoor unit (IU), a check sum for the transmission paths, for the data located in the interval under observation, said check sum enabling error correction; by checking the correctness of the data in the receiving outdoor units or by correcting small correctable errors; and by selecting, in the receiving indoor unit, on the basis of a quality factor describing the error-free quality of paths, another more error-free transmission path, in case for instance weather conditions cause errors in the currently employed connection.

Method and apparatus for changing parallel clock signals in a digital data transmission

A changeover arrangement for the clock signals of parallel transmission connections of an assured data transmission link, wherein a clock signal is sent for the transmission paths by parallel outdoor units (OU) located in succession to a common indoor unit (IU), the clock signal is received by a corresponding set of second outdoor units, where phase locked loop signals are used to achieve the lock to the signal, and subsequent to which a second IU receives information of the mode of the phase lock. In addition, when errors are caused in the employed connection, the receiving unit selects a transmission path that has fewer errors based on mode information obtained from the outdoor unit.

Method and arrangement for changing parallel clock signals in a digital data transmission

The invention relates to a multiplexing method used in a PDH network. Standard PCM signals are received in the network element, at least some of which are multiplexed on a time-division basis into the same outbound transmission frame, the capacity of the payload portion of the frame substantially corresponding to the capacity required by N PCM signals. In order that ATM cells may be transferred more advantageously than heretofore through an existing PDH network, the multiplexing is implemented as configurable in such a way that the total capacity of the payload portion cab be divided between at least two parts of variable capacity in such a way that each part can be allocated a desired portion of the total capacity of the payload portion in accordance with the current transmission requirement. A part of the payload depending on the desired capacity is allocated to at least one traffic source from a group in which a number of PCM signals constitutes a first traffic source and a number of packet data streams constitutes a second traffic source. The invention is specifically intended for transferring ATM traffic through a PDH network.

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Klaukkala, Finland

Harri Lahti