A Multicast Anti-Collision Protocol for FTDMA based RFID system

Abstract:

RFID (radio frequency identification) is a key technology supporting emerging solutions for the automation of the identification service and the mass product management. A key issue is to reduce the average time taken to identifying tags, which is called average identification time. Focusing on the issue, the paper proposes an efficient multicast protocol which is applied to the anti-collision protocol of FTDMA (frequency time deivision multiple access) based RFID system. Thanks to the compactness of a multicast protocol, simulation result shows 29.5% improvement of average identification time.

---

Presented By:

Sung-Rok Yoon, and Sin-Chong Park
Information and Communications University
119, Munji-ro, Yuseong-gu, Daejeon, Korea

---

1. Introduction
Radio frequency identification (RFID) technology has been grown for a decade, along with the development of semiconductor technology. It is applied for many industrial fields such as the distribution industry, the inventory management, the medical treatment, and so on. By attaching a RFID tag to every product, the technology will contribute the establishment of the Ubiquitous environment. An important issue of RFID is the technology to accelerate the time identifying many tags. In order to do that, the collision between multiple tags should be efficiently compromised. This function is called anti-collision protocol. Anti-collision protocol is to be classified into the ALOHA-based (or probabilistic) protocols and the tree- based (or deterministic) schemes, in terms of the method to obtain the opportunity accessing the channel. At the ALOHA-based protocols, tags access the channel by random priority. There are pure ALOHA, slotted-ALOHA, and frame-slotted-ALOHA protocols [1]. For the tree-based protocols, tags which satisfy the condition given by a reader try to access the channel. The tree-based schemes guarantee that every tag replies once during the identification time. For another point of view, the anti-collision protocols are categorized into TDMA (time division multiple access) and FDMA (frequency division multiple access). There is a hybrid scheme called FTDMA (frequency time division multiple access) as well.

Read full report
http://ieiceproceedings/ITC-CSCC2008/pdf/p509_B5-2.pdf

[attachment=5600]

---

RFID(Radio-frequency Identification)

INTRODUCTION
Radio-frequency identification (RFID) is the use of an object (typically referred to as an RFID tag) applied to or incorporated into a product, animal, or person for the purpose of identification and tracking using radio waves. Some tags can be read from several meters away and beyond the line of sight of the reader.

RFID has many applications, for example, it is used in enterprise supply chain management to improve the efficiency of inventory tracking and management. Long checkout lines at the grocery store are one of the biggest complaints about the shopping experience. Soon, these lines could disappear when the ubiquitous Universal Product Code (UPC) bar code is replaced by smart labels. These labels are called radio frequency identification (RFID) tags. RFID tags are intelligent bar codes that can talk to a networked system to track every product that we put in our shopping cart.
Unlike ubiquitous (UPC) bar-code technology, RFID technology does not require contact or line of sight for communication. RFID data can be read through the human body, clothing and non-metallic materials. Imagine going to the grocery store, filling up our cart and walking right out the door. No longer we’ll have to wait as someone rings up each item in our cart one at a time. Instead, these RFID tags will communicate with an electronic reader that will detect every item in the cart and ring each up almost instantly. The reader will be connected to a large network that will send information of our products to the retailer and product manufacturers. Our bank will then be notified and the amount of the bill will be deducted from our account. No lines, no waiting.
Outside the realm of retail merchandise, RFID tags are tracking vehicles, airline passengers, Alzheimer's patients and pets. To better understand how RFID’s work let us take a look at the components and build of a basic RFID system.

[attachment=5854]

---

RFID

INTRODUCTION
RFID is an acronym for Radio Frequency Identification. RFID is one member in the family of Automatic Identification and Data Capture (AIDC) technologies and is a fast and reliable means of identifying just about any material object.

Primarily, the two main components involved in a Radio Frequency Identification system are the Transponder and the Interrogator. Communication between the RFID reader and tags occurs wirelessly and generally does not require a line of sight between the devices.

An RFID reader typically contains a module (transmitter and receiver), a control unit and a coupling element. The reader has three main functions: energizing, demodulating and decoding. In addition, readers can be fitted with an additional interface that converts the radio waves returned from the RFID tag into a form that can then be passed on to another system, like a computer or any programmable logic controller. Anti-Collision algorithms permit the simultaneous reading of large numbers of tagged objects, while ensuring that each tag is read only once.

RFID is a sight less identification system. It is the combination of Radio Frequency and the Microchip technologies. RFID transmits the identity of an object as a unique serial number. This identity is stored in the tag chips and can be retrieved by the Readers. The components of RFID are
 Tag
 Interrogator

TAG:
Tag, also called transponder is a small device which contains a microchip. The chip is used to store the data. The tag can be programmed with specific items of information, such as an ID or serial number or a user data. The tag identifies itself by transmitting signals to the Interrogator.
There are two types of Tags namely,
 Active Tag
 Passive Tag
 Semi Passive Tag

ACTIVE TAG:
 Transmits signals from the microchip circuit through the power obtained from an internal battery
 High Signal range
 Used on large assets, such as cargo containers, rail cars, and large reusable containers
 Costlier and Larger in Size.
PASSIVE TAG:
 Contains no power source
 Obtains power from the Interrogator
 Low Signal range
 Cheaper and Smaller than active tags
SEMI-PASSIVE TAG:
 Semi-passive RFID uses an internal power source to monitor environmental conditions, but requires RF energy transferred from the Interrogator similar to passive tags to power a tag response.
 Semi-passive RFID tags use a process to generate a tag response similar to that of passive tags.
 Semi-passive tags differ from passive in that semi passive tags possess an internal power source for the tag's circuitry which allows the tag to complete other functions such as monitoring of environmental conditions and which may extend the tag signal range.