Patent EP0490441A2 successfully refreshed from Google Patents.
EP0490441A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
A method of operating a communications system, a communications system and a secondary station for use in the system
Assignee: Philips Electronics UK Ltd
•
Filing: 1991-12-06
•
Granted: —
•
Expires: 2011-12-06
Abstract
Abstract A communications system, such as DECT, comprises a plurality of geographically separate primary (or fixed) stations (PS) and a plurality of secondary (or portable) stations (SS) which are able to roam relative to the primary stations. Communication between the primary and secondary stations is by way of any one of a plurality of TDD radio channels. A primary station when idle transmits an idle beacon signal onto which an idle primary station can lock by scanning the radio channels. However a secondary station which has roamed out of coverage range of the primary stations can save battery power by progressively increasing to a maximum time value the time interval between successive scans.
Inventors
- 👤 Frank Charles Gwyn Owen
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 09:39
CPC Classifications
H; H04; H04W; H04W48/00; H04W48/20; H04W4/00; H04W4/16; H04M; H04M1/00; H04M1/72; H04M1/725; H04M1/72502; H04M1/72505; H04M1/72511; H04M1/72516; H04M1/73; H04M1/733; H04W48/16; H04M2250/00; H04M2250/08; H04W36/00; H04W36/08; H04W52/00; H04W52/02; H04W52/0209; H04W52/0225; H04W52/0241; Y; Y02; Y02D; Y02D30/00; Y02D30/70
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
144 words
A method of operating a communications system comprising at least one primary station having radio transceiving means and at least one secondary station having radio transceiving means, the or each secondary station being able to roam into and out of radio range of the or each primary station, wherein the primary and secondary stations are able to communicate with each other on any one of a plurality of channels, the or each primary station during idle periods transmits an idle beacon signal onto which an in-range secondary station can lock and wherein whenever a secondary station loses lock it scans the plurality of channels searching for an acceptable idle beacon signal, characterised in that the frequency at which an out of range secondary station rescans the plurality of channels varies with the increase in time from when the secondary station was last in lock.
Claim 2
Dependent Claim
37 words
A method as claimed in claim 1, characterised in that the frequency of rescanning decreases in time with respect to the increase in time since the secondary station was last in lock with an idle beacon signal.
Claim 3
Dependent Claim
18 words
A method as claimed in claim 2, characterised in that the frequency of rescanning is decreased in steps.
Claim 4
Dependent Claim
47 words
A method as claimed in claim 2, characterised in that the frequency of rescanning is decreased over a plurality of predetermined steps and in that the last of the predetermined steps is maintained until either an idle beacon signal is located or the secondary station is de-energised.
Claim 5
Dependent Claim
22 words
A method as claimed in claim 1, characterised in that the frequency of rescanning is adaptive to the statistics of the system.
Claim 6
Dependent Claim
142 words
A communications system comprising at least one primary station and at least one secondary station which is able to roam relative to the or each primary station, each said primary and secondary station comprising radio transceiving means capable of transmitting on one of a plurality of channels, the or each primary station being capable of transmitting an idle beacon signal when not communicating with the or a secondary station, the or each secondary station being capable of scanning the plurality channels and locking onto an idle beacon signal, characterised in that the or a secondary station includes control means which, in response to the secondary station being unable to lock onto an idle beacon signal, varies the frequency at which the plurality of channels are scanned with respect to the increase in time from when the secondary station was last in lock.
Claim 7
Dependent Claim
25 words
A system as claimed in claim 6, characterised in that the control means decreases the frequency of rescanning in steps to a predetermined maximum value.
Claim 8
Dependent Claim
84 words
A secondary station for carrying out the method as claimed in claim 1, comprising radio transceiving means for communicating with a primary station, control means which in response to the secondary station losing lock with an idle beacon transmission from a primary station, causes the transceiving means to scan other radio channels, characterised in that the control means varies the frequency at which the radio channels are rescanned with respect to the increase in time from when the secondary station was last in lock.
Claim 9
Dependent Claim
26 words
A secondary station as claimed in claim 8, characterised in that the control means decreases the frequency of rescanning in steps to a predetermined maximum value.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.