Abstract:
The invention relates to a method of measuring a time difference and a radio system employing the method, the radio system comprising base stations, terminals, time difference units and a time difference centre. A real time difference RTD of the base station is formed on the basis of measurements carried out by the time difference units by means of an observed time difference OTD and a geometrical time difference GTD in the time difference centre as a function of time, in which case the moment of occurrence of the real time difference RTD measured is connected to the real time difference RTD of the base station.
Abstract:
In telecommunications networks the problem with call forwarding restriction according to prior art is that access through call forwarding to numbers with ensuring an answer rather than possible further forwarding is not possible. The invention is based on the idea that call forwarding is allowed despite call forwarding restriction when the number to be used in forwarding the call meets special conditions set beforehand. The number is thus compared with the preset conditions and depending on the result of this comparison the call is either forwarded or not.
Abstract:
The invention relates to a method for compensating signal dispersion in an optical communication network and to an optical communication network. The dispersion compensation is carried out by constructing the network in such a way that a route having an even number of phase conjugating means can be found between any two nodes. The routing is primarily made along a route in which there is the minimum even number of phase conjugating means between the terminal nodes. A preferred embodiment of the invention is a ring network constructed of two concentric rings in such a way that both rings comprise the same node points, but the number of phase conjugating means to be installed in said rings, in the optical fibers between adjacent nodes is, for example, even in the outer ring and odd in the inner ring.
Abstract:
The objective of the invention is to increase the potential hop density of single frequency TDD radio links by allowing a set of closely located terminals to use a single channel. This is possible when transmission and reception periods of the terminals are synchronized so that the transmit period of any of the terminals in a terminal group does not overlap with the receive period of any of the terminals in the group. Synchronization is achieved by selecting at least one terminal in a hub site as a super master terminal. This terminal gives timing through a common bus to the rest of the terminals in the group. These terminals use the received timing for adjusting their own timing i.e. for adjusting the starting moment and ending moment of the transmission and reception periods in such a manner that none of terminals is sending a burst while another terminal is receiving.
Abstract:
The invention relates to a mobile communication system including mobile stations comprising transmission means for sending data over the radio path, at least one mobile exchange, and base stations having a data transmission connection with the mobile exchange, traffic channels being allocated to be used by transceiver units of the base stations for providing calls to the mobile stations, the base stations also comprising means for receiving the data sent by the mobile stations over the radio path and for forwarding said data to other parts of the system. In order for the mobile stations to be able to send data more efficiently, at least one predetermined data channel is allocated for the mobile stations to send data. In addition the system includes at least one mobile station comprising control means that independently at predetermined moments control the transmission means of the mobile station to move over to said predetermined data channel for the time the data is sent, in which case the mobile station sends said data on said data channel without a preceding channel allocation.
Abstract:
A system for recording a video session includes a video server and a client coupled to the video server using a communication path. The video server communicates a start record command. The client determines the processing capacity of the client and establishes a recording interval in response to the determined processing capacity. The recording interval indicates a time between a first recording time and a second recording time. The client records a first video frame at the first recording time in response to the start record command, and records a second video frame at the second recording time. The first video frame includes first video data and the second video frame includes second video data. The client generates a video sub-frame comprising the second video data that is different from the first video data.
Abstract:
The invention relates to the implementation of narrowband and broadband services in a telecommunications network. A splitter element is connected to a transmission link, the splitter element comprising a passive low-pass filter block connected between the transmission link and a first interface, a high-pass filter unit connected between the transmission link and a second interface, and discrete impedance converting means for adapting the first interface to the characteristic impedance of the transmission link. In order that the impedance matching required by the low-pass filter block may be implemented in an economical way yet maintaining the service quality, the impedance converting means are entirely placed between the interface of the low-pass filter block on the transmission link side and the first interface.
Abstract:
A method and system for determining a location of a user equipment using RTT measurements from a connected node B and RTT measurement of other node Bs which are not connected to the user equipment. The radio network controller of a network measures RTT of a connected node Bs and then measures RTT of non connected node Bs. Based on the RTT measurement, the distances of the user equipment from each node B is determined. Circles having radii equal to the distances of the user equipment from the nodes are used to determine the user equipment location.
Abstract:
The invention is based on the idea that wavelength of a laser transmitter in a WDM system can be changed in a controlled fashion by inducing an accurately pre-defined change in the cooler control current TEC. This, in turn, effects a controlled change in the heating or cooling operation of the cooler. As a result, a predetermined change takes place in the wavelength of the light generated by the laser. The temperature control circuit ensures that the laser temperature and, thus, wavelength, are maintained exactly at the new value. For each desired wavelength, a parameter set consisting of a pre-set laser temperature value, a laser power value and laser modulation bias values has been saved in storage in advance. When the laser wavelength is to be changed, the parameter values corresponding to the wavelength are retrieved from the storage and fed to the laser. Retrieval and feeding can be pre-programmed or carried out manually.
Abstract:
The invention relates to protection of an optical transmission connection. From the transmitting end of the connection, the same optical signal is transmitted along a first path and a second path to the receiving end, where the power level of the signal received from each path is monitored, and one of the paths is selected as the working path and the signal arriving from the said path is connected to the receiver, whereby the other path remains as a redundancy path. For the transmission connection to preserve an optimum performance also when the power level difference between the paths is varying, that path is at each time selected as the working path, where the received signal is considered at the moment in question to have the higher power level. The selection is always carried out when the power level difference between the signals reaches a predetermined threshold value, irrespective of the power level of the signal received at that time from the working path.