Array of very light readers for active rfid and location applications

A modular wide-band RFID Very Light Reader device comprising;

• (a) at least one Tag module having at least one VLSI chip integrating a UWB front end and high speed digital transceiver;
• and
• (b) a base module configured for interconnection with a plurality of said Tags modules, said base module having at least:
• (i) a controller configured to implement the Media Access Control (MAC) protocol of the system;
• and
• (ii) a communication interface subsystem that provides connection to a system network.

A method of reducing the collision occurrence in a network for communicating between multiple readers and a plurality of RF tags, the method comprising the steps of:

• (a) transmission by at least one Reader of at least one wide band interrogation signal;
• (b) reception of said interrogation signal by at least one Tag;
• (c) transmission by said Tag of a response signal in response said interrogation signal;
• (d) reception of said response signal by said Reader;
• (e) estimation by said Reader as to a quantity of wide band response signals received in response to said interrogation signal;
• (f) determination by said Reader of a round trip delay time of each said response signal;
• (g) estimation by said Reader as to whether a collision between a plurality of the wide band response signals occurred and if so,
• (i) transmission by said Reader of at least one additional wide band interrogation signal, said additional wide band interrogation signal initiating a new communications session between said Reader and said at least one RF Tag in order to reduce the collision probability between the wide band response signals transmitted by the Tags;
• and
• (h) transmission by said Reader of an acknowledgment packet to said responding Tag such that,
• (i) said Tag will not answer again to that broadcast session in case a broadcast command has to be re-transmitted due to an estimation that some collisions occurred during a previous session;
• and
• (ii) at least one other such Reader in the network receives said acknowledge packet such that said other Reader will not try again to reach said Tag, thereby lowering congestion directed toward said Tag from multiple Reader transmissions.

A system capable of reducing the collision occurrence in a network for communicating between multiple readers and a plurality of RF tags, the system comprising:

• (a) at least one Tag configured to receive at least one wide band interrogation signal, transmit a response signal in response said interrogation signal;
• (b) at least one Reader configured to transmit said interrogation signal and receive said response signal, said Reader further configured to:
• (i) estimate a quantity of wide band response signals received in response to said interrogation signal;
• (ii) determine a round trip delay time of each said response signal;
• (iii) estimate as to whether a collision between a plurality of the wide band response signals occurred and if so, transmit at least one additional wide band interrogation signal, said additional wide band interrogation signal initiating a new communications session between said Reader and said at least one RF Tag in order to reduce the collision probability between the wide band response signals transmitted by the Tags;
• and
• (iv) transmit an acknowledgment packet to said responding Tag such that, said responding Tag will not answer again to that broadcast session if a broadcast command is re-transmitted due to an estimation that some collisions occurred during a previous session;
• and
• (c) at least a second Reader in the network configured to receive said acknowledge packet such that said second Reader will not try again to reach said Tag, thereby lowering congestion directed toward said Tag from multiple Reader transmissions.