有關(guān)RFID（射頻識別）介紹
什么是RFID（射頻識別）？
What is RFID (radio frequency identification)?
RFID（射頻識別）是一種無線通信形式，它利用電磁頻譜射頻部分中的電磁或靜電耦合來唯一地識別物體、動物或人。
RFID (radio frequency identification) is a form of wireless communication that incorporates the use of electromagnetic or electrostatic coupling in the radio frequency portion of the electromagnetic spectrum to uniquely identify an object, animal or person.
RFID如何工作？
How does RFID work?
每個 RFID 系統(tǒng)都由三個組件組成：掃描 天線、 收發(fā)器和應(yīng)答器。當掃描天線和收發(fā)器組合在一起時，它們被稱為 RFID 讀取器或詢問器。 RFID 閱讀器有兩種類型：固定閱讀器和移動閱讀器。 RFID 閱讀器是一種聯(lián)網(wǎng)設(shè)備，可以是便攜式的，也可以是永久連接的。它使用無線電波傳輸激活標簽的信號。一旦激活，標簽就會將波發(fā)送回天線，并在天線處轉(zhuǎn)換成數(shù)據(jù)。
應(yīng)答器位于 RFID 標簽本身中。 RFID 標簽的讀取范圍因標簽類型、閱讀器類型、RFID 頻率以及周圍環(huán)境或其他 RFID 標簽和閱讀器的干擾等因素而異。具有更強電源的標簽也具有更長的讀取范圍。
Every RFID system consists of three components: a scanning antenna, a transceiver and a transponder. When the scanning antenna and transceiver are combined, they are referred to as an RFID reader or interrogator. There are two types of RFID readers -- fixed readers and mobile readers. The RFID reader is a network-connected device that can be portable or permanently attached. It uses radio waves to transmit signals that activate the tag. Once activated, the tag sends a wave back to the antenna, where it is translated into data.
The transponder is in the RFID tag itself. The read range for RFID tags varies based on factors including the type of tag, type of reader, RFID frequency and interference in the surrounding environment or from other RFID tags and readers. Tags that have a stronger power source also have a longer read range.
什么是RFID標簽和智能標簽？
What are RFID tags and smart labels?
RFID標簽由集成電路（IC）、天線和基板組成。 RFID 標簽中對識別信息進行編碼的部分稱為 RFID 嵌體。
RFID 標簽主要有兩種類型：
? 有源射頻識別。有源 RFID 標簽有自己的電源，通常是電池。
? 無源射頻識別。無源 RFID 標簽從讀取天線接收能量，讀取天線的電磁波會在 RFID 標簽的天線中感應(yīng)出電流。
還有半無源 RFID 標簽，這意味著電池驅(qū)動電路，而通信則由 RFID 讀取器供電。
低功耗嵌入式非易失性存儲器在每個 RFID 系統(tǒng)中都發(fā)揮著重要作用。 RFID 標簽通常保存不到 2,000 KB的數(shù)據(jù)，包括唯一標識符/序列號。標簽可以是只讀的或讀寫的，其中數(shù)據(jù)可以由讀取器添加或覆蓋現(xiàn)有數(shù)據(jù)。
RFID 標簽的讀取范圍因標簽類型、讀取器類型、RFID 頻率以及周圍環(huán)境或其他 RFID 標簽和讀取器的干擾等因素而異。由于電源更強，有源 RFID 標簽比無源 RFID 標簽具有更長的讀取范圍。
智能標簽是簡單的 RFID 標簽。這些標簽將 RFID 標簽嵌入到不干膠標簽中，并帶有條形碼。它們還可用于 RFID 和條形碼閱讀器。智能標簽可以使用桌面打印機按需打印，而RFID標簽需要設(shè)備。
RFID tags are made up of an integrated circuit (IC), an antenna and a substrate. The part of an RFID tag that encodes identifying information is called the RFID inlay.
There are two main types of RFID tags:
? Active RFID. An active RFID tag has its own power source, often a battery.
? Passive RFID. A passive RFID tag receives its power from the reading antenna, whose electromagnetic wave induces a current in the RFID tag's antenna.
There are also semi-passive RFID tags, meaning a battery runs the circuitry while communication is powered by the RFID reader.
Low-power, embedded non-volatile memory plays an important role in every RFID system. RFID tags typically hold less than 2,000 KB of data, including a unique identifier/serial number. Tags can be read-only or read-write, where data can be added by the reader or existing data overwritten.
The read range for RFID tags varies based on factors including type of tag, type of reader, RFID frequency, and interference in the surrounding environment or from other RFID tags and readers. Active RFID tags have a longer read range than passive RFID tags due to the stronger power source.
smart labels are simple RFID tags. These labels have an RFID tag embedded into an adhesive label and feature a barcode. They can also be used by both RFID and barcode readers. Smart labels can be printed on-demand using desktop printers, where RFID tags require more advanced equipment.
RFID系統(tǒng)有哪些類型？
What are the types of RFID systems?
RFID系統(tǒng)主要分為三種類型：低頻（LF）、高頻（HF）和超高頻（UHF）。微波 RFID 也可用。不同國家和地區(qū)的頻率差異很大。
? 低頻 RFID 系統(tǒng)。這些范圍從 30 KHz到 500 KHz，但典型頻率為 125 KHz。 LF RFID 的傳輸范圍很短，通常從幾英寸到不到六英尺。
? 高頻 RFID 系統(tǒng)頻率范圍為 3 MHz至 30 MHz，典型的 HF 頻率為 13.56 MHz。標準范圍從幾英寸到幾英尺。
? 超高頻 RFID 系統(tǒng)。這些范圍從 300 MHz 到 960 MHz，典型頻率為 433 MHz，通常可以在 25 英尺外讀取。
? 微波 RFID 系統(tǒng)。它們的運行頻率為 2.45 Ghz，可以在 30 多英尺外讀取。
使用的頻率取決于 RFID 應(yīng)用，實際獲得的距離有時與預(yù)期不同。例如，當美國國務(wù)院宣布將發(fā)行配備 RFID 芯片的電子護照時，它表示該芯片只能在大約 4 英寸外讀取。然而，國務(wù)院很快收到證據(jù)表明，RFID 閱讀器可以從 RFID 標簽中讀取信息，距離遠超過 4 英寸，有時甚至可達 33 英尺。
如果需要更長的讀取范圍，使用具有額外功率的標簽可以將讀取范圍擴大到 300 多英尺。
There are three main types of RFID systems: low frequency (LF), high frequency (HF) and ultra-high frequency (UHF). Microwave RFID is also available. Frequencies vary greatly by country and region.
? Low-frequency RFID systems. These range from 30 KHz to 500 KHz, though the typical frequency is 125 KHz. LF RFID has short transmission ranges, generally anywhere from a few inches to less than six feet.
? High-frequency RFID system These range from 3 MHz to 30 MHz, with the typical HF frequency being 13.56 MHz. The standard range is anywhere from a few inches to several feet.
? UHF RFID systems. These range from 300 MHz to 960 MHz, with the typical frequency of 433 MHz and can generally be read from 25-plus feet away.
? Microwave RFID systems. These run at 2.45 Ghz and can be read from 30-plus feet away.
The frequency used will depend on the RFID application, with actual obtained distances sometimes varying from what is expected. For example, when the U.S. State Department announced it would issue electronic passports enabled with an RFID chip, it said the chips would only be able to be read from approximately 4 inches away. However, the State Department soon received evidence that RFID readers could skim the information from the RFID tags from much farther than 4 inches -- sometimes upward of 33 feet away.
If longer read ranges are needed, using tags with additional power can boost read ranges to 300-plus feet.
RFID 應(yīng)用和使用案例
RFID applications and use cases
RFID 應(yīng)用和用例
RFID 的歷史可以追溯到 20 世紀 40 年代；然而，它在 20 世紀 70 年代使用得更頻繁。長期以來，標簽和閱讀器的高成本阻礙了廣泛的商業(yè)用途。隨著硬件成本的下降，RFID 的采用也有所增加。
RFID 應(yīng)用的一些常見用途包括：
? 寵物和牲畜追蹤
? 庫存管理
? 資產(chǎn)跟蹤和設(shè)備跟蹤
? 庫存控制
? 貨物和供應(yīng)鏈物流
? 車輛追蹤
? 客戶服務(wù)和損失控制
? 提高供應(yīng)鏈的可見性和分布
? 安全情況下的訪問控制
? 船運
? 衛(wèi)生保健
? 制造業(yè)
? 零售銷售
? 即按即用信用卡付款
RFID dates back to the 1940s; however, it was used more frequently in the 1970s. For a long time, the high cost of the tags and readers prohibited widespread commercial use. As hardware costs have decreased, RFID adoption has also increased.
Some common uses for RFID applications include:
? pet and livestock tracking
? inventory management
? asset tracking and equipment tracking
? inventory control
? cargo and supply chain logistics
? vehicle tracking
? customer service and loss control
? improved visibility and distribution in the supply chain
? access control in security situations
? shipping
? healthcare
? manufacturing
? retail sales
? tap-and-go credit card payments
RFID 與條形碼
RFID vs. Barcodes
使用 RFID 作為條形碼的替代品的使用正在增加。 RFID 和 條形碼 技術(shù)用于跟蹤庫存的方式類似，但它們之間存在一些重要的區(qū)別。
Using RFID as an alternative for barcodes is increasing in use. RFID and barcode technologies are used in similar ways to track inventory, but there are some important differences between them.
RFID 與 NFC
RFID vs. NFC
近場通信 (NFC) 通過使用短距離、高頻無線通信技術(shù)實現(xiàn)設(shè)備之間的數(shù)據(jù)交換。 NFC 將智能卡和讀卡器的接口組合到一個設(shè)備中。
Near-field communication (NFC) enables data to be exchanged between devices by using short-range, high-frequency wireless communication technology. NFC combines the interface of a smart card and reader into a single device.
RFID挑戰(zhàn)
RFID challenges
RFID容易出現(xiàn)兩個主要問題：
? 閱讀器沖突。當來自一個 RFID 讀取器的信號干擾第二個讀取器時，可以通過使用防沖突協(xié)議使 RFID 標簽輪流向其適當?shù)淖x取器傳輸信號來防止讀取器沖突。
? 標簽沖突。當太多標簽同時傳輸數(shù)據(jù)而使 RFID 讀取器感到困惑時，就會發(fā)生標簽沖突。選擇一次收集一個標簽信息的閱讀器可以防止這一問題。
RFID is prone to two main issues:
? Reader collision. Reader collision, when a signal from one RFID reader interferes with a second reader, can be prevented by using an anti-collision protocol to make RFID tags take turns transmitting to their appropriate reader.
? Tag collision. Tag collision occurs when too many tags confuse an RFID reader by transmitting data at the same time. Choosing a reader that gathers tag info one at a time will prevent this issue.
RFID 安全和隱私
RFID security and privacy
一個常見的 RFID 安全或隱私問題是，任何擁有兼容閱讀器的人都可以讀取 RFID 標簽數(shù)據(jù)。標簽通?？梢栽谖锲冯x開商店或供應(yīng)鏈后讀取。它們還可以在用戶不知情的情況下使用未經(jīng)授權(quán)的閱讀器進行讀取，并且如果標簽具有唯一的序列號，則可以將其與消費者相關(guān)聯(lián)。雖然這是個人隱私問題，但在軍事或醫(yī)療環(huán)境中，這可能是國家安全問題或生死攸關(guān)的問題。
由于 RFID 標簽沒有很強的計算能力，因此它們無法適應(yīng)加密，例如可能在質(zhì)詢-響應(yīng)身份驗證系統(tǒng)中使用的加密。然而，一個例外是護照中使用的 RFID 標簽——基本訪問控制 (BAC)。這里，芯片具有足夠的計算能力來解碼來自閱讀器的加密令牌，從而證明閱讀器的有效性。
在閱讀器處，打印在護照上的信息被機器掃描并用于獲取護照的密鑰。使用三項信息——護照號碼、護照持有人的出生日期和護照的到期日期——以及三項信息中每一項的校驗和數(shù)字。
研究人員表示，這意味著護照受到密碼的保護，其熵比電子商務(wù)中通常使用的密碼要少得多。它們的密鑰在護照的生命周期內(nèi)也是靜態(tài)的，因此一旦實體一次性訪問了打印的密鑰信息，無論是否經(jīng)過護照持有人的同意，護照都可以讀取，直到護照過期。
美國國務(wù)院于 2007 年采用了 BAC 系統(tǒng)，在電子護照中添加了防盜材料，以減輕未經(jīng)發(fā)現(xiàn)的竊取用戶個人信息的威脅。
A common RFID security or privacy concern is that RFID tag data can be read by anyone with a compatible reader. Tags can often be read after an item leaves a store or supply chain. They can also be read without a user's knowledge using unauthorized readers, and if a tag has a unique serial number, it can be associated to a consumer. While a privacy concern for individuals, in military or medical settings this can be a national security concern or life-or-death matter.
Because RFID tags do not have a lot of compute power, they are unable to accommodate encryption, such as might be used in a challenge-response authentication system. One exception to this, however, is specific to RFID tags used in passports -- basic access control (BAC). Here, the chip has sufficient compute power to decode an encrypted token from the reader, thus proving the validity of the reader.
At the reader, information printed on the passport is machine-scanned and used to derive a key for the passport. There are three pieces of information used -- the passport number, the passport holder's birth date and the passport's expiration date -- along with a checksum digit for each of the three.
Researchers say this means passports are protected by a password with considerably less entropy than is normally used in e-commerce. They key is also static for the life of the passport, so once an entity has had one-time access to the printed key information, the passport is readable with or without the consent of the passport bearer until the passport expires.
The U.S. State Department, which adopted the BAC system in 2007, has added an anti-skimming material to electronic passports to mitigate the threat of undetected attempts to steal users' personal information.
射頻識別標準
RFID standards
RFID 技術(shù)有多個指南和規(guī)范，但主要的標準組織是：
? 國際標準化組織 (ISO)
? 電子產(chǎn)品代碼全球公司 (EPCglobal)
? 國際電工委員會 (IEC)
每個射頻都有相關(guān)標準，包括適用于 LF RFID 的 ISO 14223 和 ISO/IEC 18000-2、適用于 HF RFID 的 ISO 15693 和 ISO/IEC 14443 以及適用于 UHF RFID 的 ISO 18000-6C。
There are several guidelines and specifications for RFID technology, but the main standards organizations are:
? International Organization for Standardization (ISO)
? Electronics Product Code Global Incorporated (EPCglobal)
? International Electrotechnical Commission (IEC)
Each radio frequency has associated standards, including ISO 14223 and ISO/IEC 18000-2 for LF RFID, ISO 15693 and ISO/IEC 14443 for HF RFID, and ISO 18000-6C for UHF RFID.
By
Sarah Amsler, Senior Managing Editor
Sharon Shea, E xecutive Editor
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