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Enhancement to RFID Repeater Placement Using Secondary Measurement Methods

IP.com Disclosure Number: IPCOM000073568D
Original Publication Date: 2005-Feb-22
Included in the Prior Art Database: 2005-Feb-22
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Abstract

A system and method for using secondary sensing methods to measure optimal placement of RFID repeaters or receivers such that a minimal number of repeaters needed is determined and the optimal location for those repeaters are discovered. The system involves using a probe device with LCD or other technology that shows RFID signal strength and the method involves a procedure for utilizing the probe in a multitude of packing and shipping configurations, in addition to a secondary weight measuring system using methods already known in the art.

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Enhancement to RFID Repeater Placement Using Secondary Measurement Methods

Radio Frequency ID (RFID) technology has been in development for some time and is now gaining significant traction in the industry. One of the problems with RFID technology is that of dead spots. RFIDs use a radio frequency which are susceptible to interference with other frequencies at or near the RFID's frequency. RFID typically uses the 800-930Mhz UHF range and devices such as pagers and some cell phones operate in this range. RFID interference patterns and dead spots can occur because of the location of the chip and the positioning and material properties of the contents within or around the package. Two or more RFID chips positioned in the wrong way can even cancel each other out.

Further there is a limit to the range of RFID chips. Because of limited range and the fact that merchandise is often packed in dense configurations with the inherent RF interference it is often not possible to get proper readings of RFID chips. This defeats the purpose of having RFIDs over other methods including bar codes. In these situations where RFID readers are not getting a proper scan the user has no choice but to rearrange the packages until he can get a proper reading. This is most often a hit and miss situation. If multiple items are scanned in a group, as in a palette of goods/boxes, then it is difficult for the operator of the RFID scanner to know how much of the palette was successfully scanned. The palette may contain 60 boxes and the RFID reader may only get a scan/reading of 50 of those boxes on the palette. In this scenario the operator may or may not know that palette contains 60 boxes and the scan may become inaccurate and lead to inaccurate inventory control.

The solution in this disclosure is necessary because the packaging of multiple units (i.e. a case of canned peas) together can attenuate RF (Radio Frequency) signals from the RFID tags if placed in less than adequate locations on the packaging. However, just knowing where to place RFID tags on a case/item falls short when units are stacked in a case and then cases stacked on a palette. RF signals emanating from the center of the case/palette can be blocked, reflected, and refracted by the other goods on the palette. With today's technology, it is expected that not all RFID signals will be detected when attempting to read a palette of goods. They can be detected, with proper placement of transmitters, but that process of determining the placement of the transmitters is time consuming and cannot be done in real time or while the goods are in transit.

Recent innovations describe systems for determining the ideal placement of individual RFID tags on either a unit of a product or on a case of a product. These innovations revolve around heat sensitive liquid crystals that change color w...