摘要:
The system comprises at least two geosynchronous satellites (S-A, S-B) having the same elliptical orbit and the same trace on the ground. The longitudes of ascending node are displaced. The moving bodies have a vertically pointed fixed antenna. The system operates for 24 hours continuously with one or other of the satellites.
摘要:
Method for controlling the phase of a decision circuit clock of a receiving system for digital data, according to which the frequencies above 1/T (T=data symbol period) are substantially eliminated, whereafter the phase deviation to be corrected is evaluated and the clock is shifted in accordance with this phase deviation, inclusive of its sign. An example of a circuit for using this method includes a lowpass filter circuit and an evaluation and phase shifting circuit for fixing the optimum decision instants of the decision circuit provided at the output of an adaptive filter.
摘要:
The present invention relates to a method for configuring a base station (10) of a mobile communication network over a software defined radio module (12), that base station (10) serving at least one mobile terminal (20, 30, 40) over an air interface (52, 53, 54) served by that software defined radio module. When selecting the communication standard for the configuration of the base station (10) the characteristics of the air interface (52, 53, 54) are taken into account. The invention also relates to a base station (10) of a mobile communication network, that base station (10) serving at least one mobile terminal (20, 30, 40) over an air interface (52, 53, 54), that base station (10) comprising a configurable software defined radio module (12). The configurable software defined radio module (12) is adapted to take into account the characteristics of the air interface (52, 53, 54) when selecting the communication standard for the configuration of the base station (10).
摘要:
A method of transmitting data between a content server (11) and a terminal (17) belonging to a discontinuous coverage network, the terminal (17) moving from a first radio coverage area (14, 161) to a second radio coverage area (14, 162) over an area (14a) comprising no radio coverage. The method includes: terminating (100) one or more protocols used by the content server (11) for the data transmission with the terminal (17) within a proxy, wherein the proxy is seen as the entry point of the discontinuous coverage network by the content server (11), and using a caching mechanism provided within the discontinuous coverage network for forwarding (200) data from the proxy to the terminal (17).
摘要:
A method of transmitting data from a specific network equipment (NE) via a radio access point (RAP1, RAP2) associated with the specific network equipment to a mobile terminal (MT1, MT2) in a discontinuous coverage network (DCN). The discontinuous coverage network comprises at least one transfer zone (TZ1, TZ2) and at least one intermediate area (IZ), wherein data is transferred to and stored in a cache (CA1, CA2) of the mobile terminal (MT1, MT2) while the mobile terminal is in the transfer zone. The proposed method includes a transfer time extension (TTEX) comprising the steps of: detecting a filling level of the cache when the mobile terminal exits the transfer area, and continuing to fill the cache of the mobile terminal outside a transfer zone until the cache filling level reaches a predefined threshold value (TV).
摘要:
The invention relates to a method of operating a radio communications network (100), wherein data is transmitted from a base station (10) of said network (100) to a terminal (20) via a radio link (15). The inventive method is characterized in that data to be transmitted from said base station (20) to said terminal (20) is transmitted in advance to said terminal depending on current data transmission conditions of said radio link (15) and stored to a cache memory (21) of said terminal (20).
摘要:
To mash coverage discontinuities, e.g. of high and low bit rate zones, when transmitting especially multimedia data to a terminal (209), it is proposed to store the data of a multimedia data stream's basic flow to a basic cache memory (315) with higher priority than storing the data of at least one enhancement flow of a multimedia data stream to at least one enhancement cache memory (317, 319), at least when said terminal (209) is likely to leave a high bit rate zone. The invention addresses as well a multimedia module (205), a terminal (209) and a computer program product adapted to this handling of multimedia streams.
摘要:
A communication system comprising a set of non-geostationary satellites provides communication links between ground stations and terminals, a communication link from a particular station via a satellite terminating at associated terminals in a limited geographical area including the station and providing a communication channel to at least some of the associated terminals. The communication link is switched to another satellite during the process of communication link handover. A communication link between a particular station and its associated terminals includes an additional communication channel which enables advance data to be transmitted between the particular station and a terminal before the latter executes a communication link handover. This data masks any interruption of communication caused by the communication link handover.
摘要:
The invention provides a method of switching a call set up between a first station and a second station from a current propagation path to a following propagation path. The method includes the following steps:a value representative of signal-to-noise ratio is measured for each of said propagation paths, namely the current path and the following path; andthe first station switches the call from a current channel on the current propagation path to a following channel on a following propagation path as a function of values representative of signal-to-noise ratio measured respectively for said current propagation path and for said following propagation path. In the method:the following call channel is reserved for said call; and:in said second station, said call is switched from the current channel to said following channel in response to said call failing to be received in the current channel.
摘要:
The present invention relates to a communications system between low-orbit satellites and terminals, in which the beams (12) of each service area (14) are illuminated according to a beam-hopping spatial scanning. For each satellite and for each terminal transmission and reception are separated in time and synchronized. Time-division duplex is used. Applicable especially to the field of space telecommunications.