Telefonaktiebolaget Lm Ericsson (publ)

Aga Aktiebolag

Lumentis Ab

Ulf A Persson

Per Johan Gustafsson

Jan-Erik Lundberg

Rune Johansson

Claudia Muñiz Garcia

Magnus G Öberg

Anna Tigerstrom

A system in radio communication comprising a controller, a first device, and a second device is provided. The first device is associated with a first particular sector of a radio communication cell and the second device is associated with a second particular sector of the radio communication cell. The first device comprises a first sector indicating hardware and the second device comprises a second sector indicating hardware. The first and second sector indicating hardware each comprises a first visual sector information relating to the first particular sector such that the first visual sector information is visible to a human, and a first electronically readable sector information relating to the first particular sector. Each device comprises a first reading arrangement for reading the electronically readable sector information.

System, method and devices related to radio communication equipment

In an optical communication link a first node () with transmission means () and a second node with receiving means () are connected by at least two optical fiber transmission paths (). One path serves as the working path, while the remaining path or paths serve as protection paths. The transmission means in the first node is connected to an optical signal power splitter () which couples the signal power from the transmitting means unequally into the different transmission paths. This uneven coupling of signal power imposes greater losses in one path than in the other or others. By arranging the splitter to couple a higher proportion of the transmitted optical power into the path that has the highest inherent losses the additional loss imposed on this path is reduced. Thus the maximum path loss between any two nodes can be minimized. This in turn means that the link length and also the size of the network is virtually unaffected by using the same transmitter.

Optical communication system with two parallel transmission paths

A node is provided in an optical communications network that utilizes a first set of add/drop filter elements for extracting and combining optical signals that are carried on wavelength division multiplexed channels in a first wavelength band. Additionally, an extraction element and a combining element for dropping and adding a service channel associated with the wavelength division multiplexed channels. The extraction element is arranged downstream of the add/drop filter elements. The extraction and combining elements are additionally adapted to drop and add, respectively, at least one further wavelength band carrying at least one optical traffic data channel.

Optical communication system

The present invention relates to a method using a node, a system comprising a node and a node for filtering signals in a wavelength division multiplexing (WDM) optical communications system, especially for re-configurably adding and dropping signals to and from an optical fibre path. The node comprising a drop filter, an add filter, a signal channel receiver, and a signal channel transmitter each being connected to a switch for signal channel relaying between said network, and signal channel dropping and adding from and to said network. The node provides low loss for relayed signals by allowing the drop filter to have a low crosstalk isolation, and provides high crosstalk isolation for dropped signal channels by connecting said receiver to the switch through an additional filter with high filtering characteristics for at least one predetermined signal channel of said signal.

Optical filtering by using an add-drop node

In networks carrying existing optical traffic on one wavelength band in combination with wavelength division multiplexed traffic carried on a second wavelength band, there is a need to enable processing of the two systems without subjecting the WDM channels to unacceptable losses. The invention meets the above need by the provision of a node in an optical communications network that has a first set of add/drop filter elements for extracting and combining optical signals carried on wavelength division multiplexed channels in a first wavelength band and an extraction element and combining element for dropping and adding, respectively, a service channel associated with the wavelength division multiplexed channels. The extraction element is arranged upstream of the add/drop filter elements relative to the direction of traffic flow and the combining element is arranged downstream of the add/drop filter elements. The extraction and combining elements are additionally adapted to drop and add, respectively, at least one further wavelength band carrying at least one optical traffic data channel.

In a WDM network, nodes connected to a common transmission medium have add/drop filters for associated channel wavelengths which passively relay all other wavelengths while subjecting these to a pass-through loss. In order to optimize the transmission distance of a network, the filter elements within a node are arranged such that those channels that have the highest link losses are relayed through as few add/drop filter elements as possible. In particular, filter elements are arranged such that received channel wavelengths with a high link loss are dropped from said transmission medium upstream of received channel wavelengths with a low link loss. Similarly, for channel wavelengths transmitted by the node, the filters are arranged such that transmitted channel wavelengths with a high link loss are added to said transmission medium downstream of transmitted channel wavelengths with a low link loss. In this manner the additional losses caused by the add/drop filters are sustained by those channels that are better able to tolerate the additional power loss.

Growing community of inventors

Skogås, Sweden

Ulf A Persson