According to research more than 30 billion devices will be wirelessly connected to the internet by 2020.
Better Relationship Between Human and Nature. Universal transport & internetworking. Improve the resource utilization ratio. Dynamic control of industry and daily life. IoT is recognized as one of the most important areas of the future Internet.
A radio-frequency identification system uses tags or labels attached to the objects to be identified. RFID Widely used in Transport and Logistics. Tracking of persons and animals. Tracking of goods. RFID inserted in passports. RFID can help detect and retrieve stolen cars.
Multiple tags in the read range cause collision. Anti-collision technology is useful in avoiding collision. Current anti-collision algorithms: Binary Search Method and Slotted Aloha. These have high current efficiency, but the system performance deteriorates with the increase of the tags.
Reader broadcasts identification loop. Tags in the range choose a time slot. Reader records non- collision tags which are out in this collision cycle. Reader starts a new cycle and repeats until all tags are read. Reader Tags
N – Number of tags C k – Number of collision time slots C 0 – Number of idle time slots C 1 – Identified time slots F – Frame length Working time: T = ∑ F i Efficiency: = ∑ C i 1 / T i Initialize F, C 0, C 1, C k and N; Start F i identify cycle Tag N i generates a random number; Save the statistics C 0, C 1 and C k C k > 0 N i+1 = N i – C 1 C 0 /F i < T 2 F i+1 = F i / 2 C 0 /F i > T 1 F i+1 = F i * 2 F i+1 = F i Calculate T and Yes No YesNo YesNo
Assume that there are 32 tags to be read in the Reader’s range Cycle 1 starts with: F=30; C 1 =0; C K =0; C 0 =0; Tag identified C 1 =1 Collision C K =1 Tag identified C 1 =2 Idle timeslot C 0 =1 Collision C K =2 After the first cycle: C 0 = 10, C K = 12 and C 1 = 8 Then, the cycles continue until all tags are read
Since the frame length of time slotted ALOHA is fixed, identifying efficiency is low. There are chances for unused time slots. Proposed system: Dynamic adjustment method of frame length into time slotted ALOHA. Key Points: Frame Length Adjustment. Grouping of tags. Tags are grouped and DFSA is applied on each group, with group length M = N/ > i.e. M = N/256.
Initialize Frame Length F, Group Number M Start Clear Tag Counter, set Slot Counter = N Corresponding tag counter + 1 Random number from tag = One of the time slot number? If tag counter > 1, C 2 +1 If tag counter = 1, then C 1 + 1 Slot counter - 1 Slot counter = 0? C 2 = 0? Reset frame length Reset the group number End Yes No Yes No
Assume that there are 758 tags to be read in the Reader’s range As per the algorithm, reader creates groups with 256 as the group size, hence group size M = 3 Within each group, DFSA is applied as shown earlier and all tags are read 12 3
Comparison of time slots Comparison of throughput
APPLICATIONS APPLICATIONS TRAFFIC MONITORINGINTELLIGENT HOME Smart Parking Monitoring of parking spaces availability in the city. Green Houses Control micro-climate conditions to maximize the production of fruits and vegetables and its quality. Indoor Air Quality Monitoring of toxic gas and oxygen levels inside chemical plants to ensure workers and goods safety. Water Leakages Detection of liquid presence outside tanks and pressure variations along pipes.
THE CHALLENGES OF IOT 1.Technological Standardization in most areas are still in fragmented state. 2.Managing and fostering rapid innovation is a challenge for the governments. 3.Privacy and security. 4.Absence of governance. How to convince users that the IoT technology will protect their data and privacy when tracking How to convince users that the IoT technology will protect their data and privacy when tracking Potential Solutions Legal & Regulatory Technical Control Social Ethic Market Self-regulation
Daily Life Traffic Issue Production Logistics Retailing Resource & Power Control So far important focus on sensors and architectures. Standardization. New considerations on : Identification. Privacy and Security. Users Interface.
QUESTIONS AND ANSWERS 1.a. Assume that an RFID reader is trying to read the tags in its range. After a cycle of identification, assume that there is C 1 successful time slots, C 0 idle time slots and C K conflict time slots. Can you estimate the number of tags in the readers range (approximately)? Answer: There are at least C 1 + 2*C K number of tags. (this question can be tricked with 2 nd or 3 rd identification cycle) 1.b. Assume that there are 80 tags in the RFID reader’s range that are to be read. Assume that in the first conflicting cycle, there are 30 identified time slots, 10 idle time slots. Identify the number of conflicting time slots in this first identification cycle (approximately). Answer: In the first cycle, we know that: Total number of tags = 80; Number of identified time slots = C 1 = 30; Idle time slots = C 0 = 10; Hence, Number of unidentified tags = 50 Number of unidentified tags = at least 2 * C K (Collision time slots) Hence, C K = 25 (approximately)
QUESTIONS AND ANSWERS 2. Assume that in an RFID infrastructure there were 40 tags to be read. The reader was operated for three identification cycles with the frame size 30. In the first identification cycle, there were 8 collision time slots and 8 idle time slots. In the second identification cycle, there were 10 collision time slots and 10 idle time slots and in the third, 3 collision time slots and 14 idle time slots. Calculate the system efficiency. Answer: Identified time slots: In the first cycle: C K = 8 and C 0 = 8. Hence, C 1 = Total time slots – (C K +C 0 ) = 14. Likewise, in second cycle: C 1 = 10. In third cycle: C 1 = 13 System efficiency = ∑C 1 / Total frame length Hence, System efficiency = 37/90 = 41.1%
QUESTIONS AND ANSWERS 3. In IoT architecture, there are three layers: Service layer, Network layer and Context-aware layer. The sub layers of these layers are shown in the picture below, Can you name the layers to which these sub layers belong and mention the functions of at least two layers? 1 3 2
QUESTIONS AND ANSWERS Answer: Following are the layers to which those sub layers belong: 1.Service Layer 2.Context aware layer 3.Network layer All sub layers are shown in the next slide. Hence the question can be tricked with other sub layers. Functions: 1.Service Layer: Performs restructuring, cleaning and combining of complex data Provides the following services: Directory service, market-to-market service, Quality of Service, facility management, etc. Transforms information to content and provides good user interface 2.Context aware Layer: Perceives and collects information from the physical world Includes wireless sensor networks, tags and reader-writers and RFID system
QUESTIONS AND ANSWERS 3.Network Layer: Includes access network and core network Provides transparent data transmission capacity Provides an efficient, reliable and trusted network infrastructure platform to upper layer 2 3 11 1 2 All sub layers and the layer numbers those belong to