Patent US2747024A successfully refreshed from Google Patents.
EP0445887A2
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EP
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Method of optimising the transmission of idle beacon messages in a communications system and a communications system operable in accordance with the method
Assignee: Philips Electronics UK Ltd
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Filing: 1991-03-04
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Granted: —
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Expires: 2011-03-04
Abstract
Abstract In some TDD communications systems such as DECT it has been proposed that in an idle period a primary (or base) station transmits some basic system and timing information as a normal idle beacon message once every frame and that paging messages to secondary stations (or portables) be sent once every 16 frames. In relatively long idle periods, for example at night, these frequent normal idle beacon messages are not required and represent a source of undesirable interference and a waste of power. In order to reduce this undesirable interference it is proposed that the primary station, subject to certain conditions being determined by the primary station, invites in-range secondary stations to participate in a low duty cycle link mode in which the primary station transmits paging messages as required and low duty link reassurance messages at relatively long intervals. In this mode the secondary stations are controlled to wake up at the required intervals. However, if the surrounding interference increases, the system reverts to the normal idle state.
Inventors
- 👤 Frank Charles Gwyn Owen
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-24 04:42
CPC Classifications
H; H04; H04W; H04W52/00; H04W52/02; H04M; H04M1/00; H04M1/72; H04M1/725; H04M1/733; H04W48/00; H04W48/08; H04W48/12; H04M2250/00; H04M2250/08; H04W52/0209; H04W52/0212; H04W52/0216; Y; Y02; Y02D; Y02D30/00; Y02D30/70
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
144 words
A method of optimising the transmission of idle beacon messages by a primary station in a communications system comprising a primary station and a transportable secondary station which communicates with the primary station by way of a radio link on one of a plurality of channels, the method comprising the primary station monitoring the traffic history and local interference environment during an idle period and in response to the conditions of the primary station not having a radio link established with a secondary station after the expiry of a predetermined time interval and detecting a level of surrounding interference not exceeding a certain level, the primary station adopts, a low duty cycle beacon mode in which the frequency of the transmitted idle beacon messages is less than the normal idle beacon transmissions transmitted by idle primary stations when said conditions have not been detected.
Claim 2
Dependent Claim
116 words
A method as claimed in Claim 1, characterised in that the primary station in response to detecting said conditions, transmits a low duty cycle request message as a paging signal, in that a secondary station in response to the receipt of the low duty cycle request message, transmits a low duty link request message over a time interval at least equal to the length of time required by the primary station to monitor all the available channels, and in that the primary station sends a low duty link confirm signal to the or each secondary station which has transmitted a low duty link request message, provided that excessive interference is not detected on the respective channel.
Claim 3
Dependent Claim
42 words
A method as claimed in Claim 2, characterised in that a secondary station not receiving a low duty link confirm signal within a predetermined time, scans available channels in order to try and set-up a low duty cycle link on another channel.
Claim 4
Independent Claim
38 words
A method as claimed in any one of Claims 1 to 3, characterised in that, when the primary station is operating in a low duty cycle beacon mode, it transmits low duty link reassurance signals at predetermined intervals.
Claim 5
Dependent Claim
80 words
A method as claimed in claim 2 or 3 or Claim 4 when appended to Claim 2 to 3, characterised in that a secondary station coming into range of a primary station operating in a low duty cycle beacon mode and wanting to establish a similar link with the primary station, transmits a low duty cycle request message at regular intervals over a time period which exceeds the time required by the primary station to monitor all the available channels.
Claim 6
Dependent Claim
162 words
A communications system comprising at least one primary station and at least one secondary station, the primary and secondary stations having transceiving means for establishing a radio link between a primary and a secondary station on one of a plurality of channels, means for scanning said plurality of channels, means for monitoring the traffic history in said channels and means for monitoring the local interference environment, wherein the or each primary station has means for determining the time elapsed since it last established a link with a secondary station and interference level determining means, and wherein the primary station further includes means responsive to determining that a link has not been established after the expiry of a predetermined time interval and to detecting that the level of surrounding interference has not exceeded a certain level for transmitting a low duty cycle request message as a paging signal to in-range secondary station(s) inviting it (or them) to enter a low duty cycle beacon.
Claim 7
Dependent Claim
74 words
A system as claimed in Claim 6, characterised in that the secondary station has means responsive to the receipt of a low duty cycle request message for selecting a physical channel and for transmitting a low duty cycle link request message over a predetermined time interval and in that the primary station has means responsive to the receipt of a low duty cycle link request message for transmitting a low duty link confirm signal.
Claim 8
Dependent Claim
73 words
A system as claimed in Claim 7, characterised in that the secondary station includes timing means which in response to the secondary station not receiving a low duty link confirm signal within a predetermined time, initiates scanning of the physical channels, said local interference monitoring means determining the levels of interference on said physical channels and in that said secondary station transmits a low duty cycle link request message on an acceptable channel.
Claim 9
Dependent Claim
26 words
A system as claimed in Claim 8, characterised in that the primary station has means for generating a low duty link reassurance signal at predetermined intervals.
Claim 10
Dependent Claim
145 words
A primary station for use in the communications system as claimed in Claim 6, comprising transceiving means for establishing a radio link between a primary and a secondary station on one of a plurality of channels, means for scanning said plurality of channels, means for monitoring the traffic history in said channels, means for determining the time elapsed since it last established a link with a secondary station, means for monitoring the local interference environment, said monitoring means including level determining means, and means responsive to determining that a link has not been established after the expiry of a predetermined time interval and to detecting that the level of surrounding interference has not exceeded a certain level, for transmitting a low duty cycle request message as a paging signal to in-range secondary station(s) inviting it (or them) to enter a low duty cycle beacon mode.
References Cited (Backward Citations)
No citation records indexed.
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