Methods for Robust Communication in Ultra Wideband (UWB) Radiofrequency Identification (RFID)

The system Ultra Wide Band - RFID is made by a reader that interrogates multiple tags (passive or semi-passive) in the vicinity by transmitting a query signal.

Title of the patent Methods for Robust Communication in Ultra Wideband (UWB) Radiofrequency Identification (RFID)
Thematic area Electrical, electronic and information engineering
Ownership Alma Mater Studiorum – Università di Bologna
Inventors Davide Dardari
Protection Italy, USA
Licensing status Available for licensing agreement
Keywords RFID, UWB, backscatter modulation, passive tags, clutter removal
Filed on Feb 29, 2008

This invention is in the background of radio frequency identification (Radiofrequency Identification, RFID)-type (semi)-passive to electromagnetic coupling. An RFID system consists of a reader and one or more tags each associated with an object. The reader generates an interrogation signal that is received by the tag. In response to the received signal, the tags send a signal to the reader that, in systems (semi-) passive, is made using the reflection signal resulting from the query of the tag (backscatter). The reflected signal can contain specific information on the tag, such as the identifier of the object.

Currently, the systems have the following limits:

  • strong limitations on the maximum distance for reading / writing (operating range), which is typically less than 3-4 meters
  • maximum number of tags at once manageable by a particular reader is strongly limited by high probability of collision of signals from the tags present in the same area;
  • problems for the security of information transmitted;
  • lack of protection against the presence of interference.

The system Ultra Wide Band (UWB) - RFID is made by a reader that interrogates multiple tags (passive or semi-passive) in the vicinity by transmitting a query signal. The tags respond to reader via backscatter modulation that is to vary the load as a function of the antenna that the tag sends the reader (typically the identifier). For the particular configuration of the reader, you can use a modulation and a sequence such that the communication robust than the unwanted reflections

The innovative components of this system are as follows:

  • architecture of a UWB tag can implement different modulation schemes of backscatter
  • a signal transmitted by reader
  • a method of using backscatter modulation architecture or part of the proposal
  • a method of processing the signal received from the reader to reduce the presence of unwanted reflections of the signal caused by the structure of your tag.

  • excellent penetration through walls;
  • low average power transmitted;
  • higher degree of security (only those who know the sequence used by the reader and the tag can decode the data);
  • resistance to interference;
  • high spatial resolution and temporal;
  • high number of tags at once manageable;
  • coexistence in the same area more UWB-RFID systems by assigning different sequences.