Media access control (MAC) for an active RFID system
First Claim
1. A system for radio frequency communication between Readers and Tags, the system comprising;
- (a) at least one tag Reader;
(b) a plurality of Tags deployed in a region in which at least some of the Tags are in radio communication with said tag Reader, at least some tags are in radio communication with other Tags in said plurality of Tags, and each tag is associated with a unique tag ID; and
(c) a Media Access Control protocol according to which;
said tag Reader is configured to send and receive radio communications to and from at least some of said plurality of Tags,said plurality of Tags are configured to send and receive radio communications to and from said tag Reader and other Tags in said plurality of Tags, wherein said plurality of Tags are divided into groups based on at least part of the unique ID of each tag, andwherein said tag Reader is configured to initiate a relay session after a rate of direct replies from said plurality of tags falls below a predetermined threshold, wherein initiation of the relay session causes at least one of the Tags to relay radio communications to or from another Tag that has not received the radio communication from said tag Reader.
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Accused Products
Abstract
A system of radio frequency communication between Readers and Tags having a scalable Media Access Control (MAC) protocol for an active RFID system employing multiple access. The system comprising at least one tag Reader and a plurality of Tags each having a unique tag ID and deployed in a region in which at least some of the Tags are in radio communication with the tag Reader A multi-dimensional addressing scheme of the MAC protocol enables division of the plurality of Tags into a number of groups for different stages of MAC protocol processing, based on different portions of the tag ID. The MAC has an inherent flexibility in the sense that it allows readers to communicate with different versions of tags and also optimize communication parameters to reader'"'"'s capabilities, without pre-configuration of the tags. Furthermore, the MAC supports means to achieve very high access reliability, such as relay between tags.
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Citations
14 Claims
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1. A system for radio frequency communication between Readers and Tags, the system comprising;
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(a) at least one tag Reader; (b) a plurality of Tags deployed in a region in which at least some of the Tags are in radio communication with said tag Reader, at least some tags are in radio communication with other Tags in said plurality of Tags, and each tag is associated with a unique tag ID; and (c) a Media Access Control protocol according to which; said tag Reader is configured to send and receive radio communications to and from at least some of said plurality of Tags, said plurality of Tags are configured to send and receive radio communications to and from said tag Reader and other Tags in said plurality of Tags, wherein said plurality of Tags are divided into groups based on at least part of the unique ID of each tag, and wherein said tag Reader is configured to initiate a relay session after a rate of direct replies from said plurality of tags falls below a predetermined threshold, wherein initiation of the relay session causes at least one of the Tags to relay radio communications to or from another Tag that has not received the radio communication from said tag Reader. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A system for radio frequency communication between Readers and Tags, the system comprising;
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(a) at least one tag Reader; (b) a plurality of Tags deployed in a region in which at least some of the Tags are in radio communication with said tag Reader, and wherein at least some tags are in radio communication with other Tags in said plurality of Tags; and (c) a Media Access Control protocol according to which; said tag Reader is configured to send and receive radio communications to and from at least some of said plurality of Tags, said plurality of Tags are configured to send and receive radio communications to and from said tag Reader and other Tags in said plurality of Tags, and said Media Access Control protocol is configured to control said radio communication between said tag Reader and said plurality of Tags; wherein said Media Access Control protocol includes tag reply parameters in each said radio communication so as to enable tags to respond to said tag Reader in a manner that is compatible with that tag Reader'"'"'s capabilities, wherein said tag reply parameters comprise indications of the tag Reader'"'"'s capabilities; and wherein said plurality of Tags includes at least one Tag that is configured to transmit or receive a given radio communication, said given radio communication including a block of variable length wherein a first generation receiving Tag is configured to forward said block without modification and a second generation receiving Tag is configured to decode and modify said block.
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9. A system for radio frequency communication between Readers and Tags, the system comprising;
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(a) at least one tag Reader; (b) a plurality of Tags deployed in a region in which at least some of the Tags are in radio communication with said tag Reader, at least some tags are in radio communication with other Tags in said plurality of Tags, and each tag is associated with a unique tag ID; and (c) a Media Access Control protocol according to which; said tag Reader is configured to send and receive radio communications to and from at least some of said plurality of Tags, said plurality of Tags are configured to send and receive radio communications to and from said tag Reader and other Tags in said plurality of Tags, wherein said plurality of Tags are divided into groups based on at least part of the unique ID of each tag, and said Media Access Control protocol is configured to control said radio communication between said tag Reader and said plurality of Tags; wherein said radio communication includes an indication of a payload start point, and wherein each tag Reader and/or Tag is configured to decode that portion of said Media Access Control protocol with which the respective generation of tag Reader and/or Tag is familiar, ignore that portion of said Media Access Control protocol with which the respective generation of tag Reader and/or Tag is unfamiliar, and jump to said payload start point, thereby allowing tag Readers to communicate with a mixture of tag generations; wherein said tag Reader is configured to initiate a relay session after a rate of direct replies from said plurality of Tags falls below a predetermined threshold, wherein initiation of the relay session causes at least one of the Tags to relay radio communications to or from another Tag that has not received the radio communication from said tag Reader. - View Dependent Claims (10, 11, 12)
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13. A system for radio frequency communication between Readers and Tags, the system comprising;
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(a) at least one tag Reader; (b) a plurality of Tags deployed in a region in which at least some of the Tags are in radio communication with said tag Reader, wherein at least some tags are in radio communication with other Tags in said plurality of Tags; and (c) a Media Access Control protocol according to which; said tag Reader is configured to send and receive radio communications to and from at least some of said plurality of Tags, said plurality of Tags are configured to send and receive radio communication to and from said tag Reader and other Tags in said plurality of Tags, and said Media Access Control protocol is configured to control said radio communication between said tag Reader and said plurality of Tags; wherein said plurality of tags includes at least one Tag that is configured to transmit or receive a given radio communication, said given radio communication including a block of variable length wherein a first generation receiving Tag is configured to forward said block without modification and a second generation receiving Tag is configured to decode and modify said block. - View Dependent Claims (14)
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Specification