Method of power negotiation between two contactless devices
AssigneeGemalto SA
InventorJean-Paul Caruana
Life of this patent
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Abstract
The invention is a method of power negotiation between a first contactless device and a second contactless device which provides an electromagnetic field set to a first power level. The method comprises the steps of: a) sending a request from the first device to the second device. The request targets a second power level and an associated duration. The next step is: b) sending a response to the first device. The response reflects a decision of the second device corresponding to the request. The final step is: c) switching the electromagnetic field to the second power level if the decision is positive.
Claims16
A method of power negotiation between a first contactless device and a second contactless device, said second contactless device providing an electromagnetic field which is set to a first power level, said first contactless device using the electromagnetic field as an energy source, wherein said method comprises the steps of:
- a) sending a request from the first device to the second device, said request targeting a second power level and a duration;
- b) sending, to the first device, a response, corresponding to the request, said response (i) reflecting a decision of the second device by indicating acceptance or rejection of said request, and (ii) including, at least when indicating acceptance of said request, power capabilities of the second device that define the minimum and maximum power levels which may be provided by the second device;
- and
- c) if the decision indicates acceptance of said request, and subsequent to sending the response to the second device, switching the electromagnetic field to said second power level.
A first contactless device configured to be used in an electromagnetic field which is set to a first power level, said first contactless device using the electromagnetic field as an energy source, said first contactless device comprising:
- a first means able to identify said first power level,
- a second means able to identify a second power level and an associated duration,
- a third means configured to build a request targeting said second power level and duration;
- and
- a fourth means configured to receive a response from a second device (i) indicating acceptance or rejection of said request and (ii) including, at least when indicating acceptance of said request, power capabilities of the second device that define the minimum and maximum power levels which may be provided by the second device.
A second contactless device, comprising a communication means configured to provide an electromagnetic field which can be set to first and second power levels, and wherein said second device comprises a negotiation means configured to:
- analyze a request coming from a first contactless device requesting a switching to a second power level for a duration,
- make a decision with respect to acceptance or rejection of the request;
- send a response to the first contactless device, the response (i) reflecting said decision by indicating acceptance or rejection of said request and (ii) including, at least when indicating acceptance of said request, power capabilities of the second contactless device that define the minimum and maximum power levels which may be provided by the contactless device;
- and
- if the decision indicates acceptance of said request, and subsequent to sending the response to the second contactless device, switch the electromagnetic field to said second power level.
Dependencies are inferred from the claim text.