Technical articles

"How fast can Trolleyponder protocol scan 1000 items in a single scan?"

With a technology such as Trolleyponder, where the technology supports 4 to 6 meter reading ranges and multiple articles being present at the same time, an important feature of the design of the system is at what point do the number of goods being read simultaneously overload the protocol. In RFID systems that have a read range of only a few centimeters, very seldom could there be more than one tagged item in the reading zone at a time, and occasionally a few. In this situation the protocol can either not have any anticollision properties, or it can have fairly simple anticollision properties to cater for a few tags at a time.

When however the reading range increases to a few meters and the technology has been designed as a barcode replacement technology such as could be needed in a Supermarket to scan the items at Goods Receiving, in the stock holding areas, or at the checkout; the protocol needs to handle a large number of items at a time without overloading.

Another feature of an RFID scanning system needed for such an application, is its ability to read goods that are randomly orientated with regard to the preferred orientation of the reader. This term is called polarisation and is an important aspect in RFID as for certain polarisation discrepancies between the reader and the tag, no energy is transferrable between the tag and the reader or vice versa. Trolleyponder design and protocol has addressed this situation and provides full 3 dimensional scanning if needed.

The graph below is from the Trolleyponder Protocol simulator showing the ability of Trolleyponder protocol to scan 1000 items that are randomly orientated in a single scanning session, with no physical movement of the goods.

• The graph shows how above 500 tags remaining the protocol slows down due to the large number of clashes occuring between the tags, but the system still reads 1000 items at a steady rate.
• The time is based on using the preferred 10KHz data rate for data transfer, but this can easily be increased in which case the read time will shorten proportionately.
• In the model the tags are randomly distributed between the X,XY,Y,YZ,Z and ZX axis
• The tags can include a switchable EAS feature that would be activated at the same time as the tags are scanned
• To solve the 1000 tags the protocol will need to resolve approximately 44000 conflicts showing how robust it is.
• The protocol does not use the data of the tag for identification, and all the 1000 tags could even have identical data values if needed.
• Although the protocol handles large quantities of tags, to read a tag in the single tag scenario only takes 0.025seconds using the above clock rate.
• Reading 100 tags that are 3 D randomly orientated should take only less than 4.5 seconds using the same clock rate.
• The tags produced by licensees following the Trolleyponder design should achieve these simulated results in production.