Abstract:
A high speed satellite-based laser communications system and method for communications between a satellite-based transmitter system and a ground-based receiver over a free space optical link. The satellite-based transmitter system includes an encoder to encode data, a polarization modulator to linearly polarize the encoded data, one or at least two transmitters to transmit the laser beam, and a quarter-wave optical wave plate to circularly polarize the signal to be transmitted. The ground-based receiver includes an automatic gain control to apply AGC to the received data before the polarizations are reversed and the data is decoded. The system enables an increased data throughput and reduces or eliminates the effects of signal fading.
Abstract:
A node in an optical communications network receives optical packets at its input. It determines a priority assigned to each optical packet. When the optical packet is a transit packet destined for another node then, if the packet is determined to have a relatively higher priority, it is output from the node via a continuous-flow transmission path. Other transit packets having relatively lower priorities are sent via an alternative transmission path that may include queues or buffers resulting in a variable delay.
Abstract:
The present invention relates in general to communication systems, and more specifically towards methods, systems, and devices that help improve transmission rates and spectral efficiency of intensity modulated (IM) or power modulated channels utilizing multi-level pulse amplitude modulation PAM-M. In an embodiment, the present invention used an iterative algorithm to open the eyes of an eye diagram in a relatively short number of steps. The algorithm, which may not require previous characterization of the channel, utilizes pseudo-random sequences, such as PSBS15 or PRQS10, and adaptive non-linear equalizers to optimize the pre-distortion taps.
Abstract:
A method for transmitting data over an optical super-channel partitions the data unequally into a set of data streams for transmission over the set of sub-channels of the super-channel, such that a size of a first data stream for transmission over a first sub-channel is different than a size of a second data stream of the data for transmission over a second sub-channel. The method encodes each data stream of the data with an error correction code (ECC) having different ECC rates to produce a set of encoded data streams and transmits concurrently the set of encoded data streams over the set of sub-channels of the super-channel. Accordingly, the method uses an adaptive ECC for optical super-channels, such that a first ECC rate for encoding the first data stream is different than a second ECC rate for encoding the second data stream.
Abstract:
In a communications network, a node receives a transit packet. The priority assigned to the transit packet is determined and when it has a low priority then the transit packet is removed and a higher priority packet is inserted in the resulting vacancy.
Abstract:
In a communications network, expired packets are recognised and removed by comparing a phase value received with the packet and a phase value previously received via the network on a master node. The packet is discarded when the difference between the value exceeds a predetermined amount.
Abstract:
A telecommunication system (1) provides bi-directional communication between TDM signals on one side and ATM signals on the other. An ATM aggregate (10) receives and transmits ATM signals, and a TDM interface (2) receives and transmits TDM signals. A format converter has an ATM bus (9) and a TDM bus (4) connected to their respective interfaces. Service-specific adapters (5-8) are connected between the buses.
Abstract:
A first data flow (DS1) for a first data transmission system (DÜ1) with a first data rate contains ATM data cells (2, 3, 4) and structure data (10, 11, 12) allocated to a section (13) consisting of several ATM cells and divided and spaced out according to predetermined instructions. The data flow (DS1) is converted, while retaining its ATM data cell format, into a second data flow (DS2) containing only ATM data cells for a second data transmission system (DÜ2) with a second, higher data rate. Here, the structure data (10, 11, 12) are separated from the first data flow and entered into a marked structure cell (64) with an ATM data cell format for the section concerned. The structure cell (64) is inserted into a second data flow (DS2) so as partly to fill an unoccupied section resulting from the differing data rates.