Telefonaktiebolaget Lm Ericsson (Publ)

Per-Ola Andersson

Tomas Thyni

Annikki Welin

Mats Forsman

Lars Helge Thylen

Sven A Persson

A network node enables a wireless device to communicate with a local service device, such as a printer or a projector, of a Local Area Network (LAN) or Wireless Local Area Network (WLAN). The network node is connected both to a communication network and to the LAN or WLAN. The method includes identifying a multicast Domain Name System (mDNS) request, where the mDNS request is received from the wireless device, and assigning a LinkLocal (LL)-address for the wireless device. The method retrieves a local IP-address of an Authentication and Authorization Service (AA-S) having authorization information regarding a local service device, and authenticates, with the AA-S which type of services, that the wireless device is authorized to use. A local IP-address of the local service device is retrieved, and service data is conveyed between the wireless device and the local service device, by applying the LL-address of the local service device.

Method for accessing local services in WLANs

The invention relates to a fibre-optic Mach-Zehnder Interferometer for measuring such as change in length. Two light conducting fibres (1,2) are connected to a coherent light source (5). A measurement converter (6), actuated by a measurement quantity (P) changes the length of the optical path and thereby the phase angle for the light wave in one fibre (2). The phase angles for the light waves in the fibres (1, 2) are compared and a corresponding output signal (I) is fed back to compensate for the phase angle change in the measurement converter (6). To make the comparison result (I) independent of the light intensities in the light conducting fibres (1,2) these are connected to an opto-electronic directional coupler (7). This is selected such that the output signal (I) varies as the phase displacement .phi., according to the relationship: I=2.times.A.times.B.times.sin .phi., where A and B are the amplitudes of the light waves in the fibres (1,2). By using the directional coupler (7), the interferometer can be made simple and accurate. The opto-electronic coupler ( 7) allows the use of polarized light, whereby accuracy may be further improved.

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Saltsjöbaden, Sweden

Per-Ola Andersson