Europe's largest UHF EPC (European Product Code) Project

In Europe, the Spanish Post Office "Correos" has implemented what they say is Europe's largest UHF RFID system for any sector. Correos ships 25 million articles every day, utilizing 30,000 boxes and 11,500 vehicles.
The RFID implementation uses 332 UHF Gen2 readers and 1,992 reader antennas supplied by Symbol Technologies. These are installed in sorting centers in 16 cities across Spain. Some 5,000 passive RFID tags are employed, which are reused. A tag is inserted into an envelope and sent as any other piece of mail through the system. The readers throughout the postal system read the tags, such as when they first enter the sorting center; when they are taken to the automation room; and when they are dispatched. The RFID system monitors the movement of the letters and logs the performance of the postal system in real time. At any one time thousands of tags are in the mail supply chain, each building up a picture of the performance of the postal system. This allows Correos to quickly detect bottlenecks or delays and tackle these. As tags are received at different addresses they are sent back again to another address to monitor the mail flow. The central server which is in Madrid also monitors the reader network through the country to ensure that each reader is operating correctly. The passive tags cost less than 30 Euro cents each and weigh a few grams.

One important point is that, like many other European countries, the UHF regulations in Spain are incredibly limiting where readers are close to each other. Correos reports that they were given a six month dispensation by the Spanish government to use UHF power levels and protocols similar to those of the US. This is the only way they could have adopted RFID as readers are close to each other in their sorting centers. For example, in a previous issue of Smart Labels Analyst IDTechEx revealed that Tesco in the UK had to halt its roll out of RFID because readers on dock doors were not turning on due to the sensitivity of the European Listen Before Talk (LBT) protocol. The success of the system in government-owned Correos with relaxed UHF regulations has had a positive effect – they say the government is now looking to change the UHF licence regulations in early 2007.

The project also utilizes semi passive tags operating at UHF, with 34 readers and 135 reader antennas deployed in four centers. The tags here cost Euro 30 each, weigh 12 grams and incorporate a laminar lithium battery, making them about the same size and thickness as a credit card. These tags are attached to the bins that post is transported in. Semi passive tags are used because the bins are metal and passive tags would not give satisfactory read performances.

With both systems Correos' objective was to achieve a 95% read rate. In reality, they achieved a near 100% read rate every time. AIDA Centre, the company who did the systems integration, told IDTechEx that the main challenges they overcame were the mechanical protection of the semi passive tags, and for the passive tags they were picking up cross readings in dense reader environments, such as readers on a dock doorways next to each other reading tags going through a different portal. AIDA solved this by mounting motion sensors on each dock, so the reader for that dock would only turn on when the trolley was approaching it. They also developed reader algorithms to perform better in this reader dense environment.

In the next phase Correos intends to tag 12,000 trolleys with robust semi passive tags.

Speaking at the POST-EXPO show in Amsterdam in late, there was some question if passive UHF should be used at all because IPC's active tag system is already globally embedded and does the same function. Correos intended to use this as a test to see how passive UHF could perform in relation to active tags and reported very good read rates, saying the cheaper passive tags is a bonus. However, others such as Korean Post say tagging mail in bags is fine with passive tags, but as most postal operators use metal roll cages active tags are needed.