A method of identification of an item using phase data for movement detection

A method of identification of an item in a system, the system comprising:

• a conveyor belt,
• a conveyor belt controller,
• a reader comprising an antenna, the antenna being arranged at a read point along the conveyor belt and configured for receiving a signal transmitted from a tag, the reader being operable to receive at least one reading from the tag via the antenna and extract from the reading a measurement of the phase of the signal transmitted by the tag and received by the antenna of the reader,
• wherein the method comprises:
• placing an item on the conveyor belt;
• by the reader receiving readings from the tag and extracting signal phase measurements from the readings;
• by the conveyor belt controller starting the conveyor belt at a first time instant t1 after the item has been placed on the conveyor belt;
• by the conveyor belt controller stopping the conveyor belt at a second time instant t2, when the item has passed the antenna of the reader, the first and second time instants ti, t2 defining a time window W;
• and
• by the reader associating the tag to the item if the pattern of the phase measurements of the tag comprises changing phase values within the time window and substantially constant phase values before and after the time window W corresponding to the movement of the item on the conveyor belt only within the time window
• whereby the identification of the item is accomplished.