摘要:
The location of a subscriber device in a wireless cellular communications system is established by transmitting digital data signals to a cellular digital data receiver of the subscriber device from at least three different cellular cell site transmitters at known locations. Each data signal has a time-synchronized synchronization signal, preferably synchronized through the time signals of the global positioning system. The time of arrival of each of the time-synchronized synchronization signals is determined with respect to an internal clock of the receiver. The location of the subscriber device is established from the locations of the cell sites and the times of arrival of the synchronization signals relative to the internal clock.
摘要:
An satellite-based internet access includes uses a distributed proxy server that reduces a delay associated with the retrieval of inline objects of web pages. The distributed proxy server includes a first component which runs on the browser side of the satellite link and communicates with web browsers, and a second component which runs on an Internet side of the satellite link and communicates with web servers. When a web page is requested over the satellite link, the second component determines whether the parent file includes any references to inline objects, and prefetches each such inline object. The prefetched objects are transmitted over the satellite link to the first component, which in-turn stores the prefetched objects in a cache and provides the prefetched objects to the requesting web browser. The first component may also block browser requests for prefetched inline objects from unnecessarily being transmitted over the satellite link.
摘要:
In an internet access system which includes a satellite link, a distributed proxy server (68) is provided which reduces a delay associated with the retrieval of inline objects of web pages. The distributed proxy server (68) includes an access point component (70) and a satellite gateway component (72). The access point component (70) runs on the client (browser) side of the satellite link and communicates with web browsers (20A-20N). The satellite gateway component (72) runs on the internet side of the satellite link and communicates with web servers (26). As a web page is retrieved over the satellite link, the satellite gateway component (72) parses the base file component of the web page to identify any references to inline objects of the web page, and prefetches each such inline object. The distributed proxy server thereby eliminates the delays normally associated with (a) waiting for the web browser (20) to receive the base component and request the object(s), and (b) waiting for the browser's object request(s) to be transmitted over the satellite link. The prefetched objects are transmitted over the satellite link to the access point component (70), which in-turn stores the prefetched objects in an object cache (71). When a web browser (20) requests an inline object, the access point component (70) checks the cache (71), and if the object resides therein, returns the object to the browser (20) without forwarding the object request over the satellite link. Traffic over the forward satellite link is thus reduced. The method implemented by the distributed proxy server (68) can also be used to reduce delays and traffic over other types of links, including non-wireless links.
摘要:
A distributed proxy server is provided which reduces a delay associated with the retrieval of inline objects of web pages retrieved over a satellite link. The distributed proxy server includes a first component which runs on the browser side of the satellite link and communicates with web browsers, and a second component which runs on an Internet side of the satellite link and communicates with web servers. When a web page is requested over the satellite link and communicates with web servers. When a web page is requested over the satellite ink, the second component determines whether the parent file includes any references to inline objects, and prefetches each such inline object. The prefetched objects are transmitted over the satellite link to the first component, which in-turn stores the prefetched objets in a cache and provides the prefetched objects to the requesting web browser. The first component may also block browser requests for prefetched inline objects from unnecessarily being transmitted over the satellite link.