Power-efficient Communication Protocol for Social Networking Tags for Visually Impaired

Size: px
Start display at page:

Download "Power-efficient Communication Protocol for Social Networking Tags for Visually Impaired"

Transcription

1 Power-efficient Communication Protocol for Social Networking Tags for Visually Impaired Problem Social Networking Tags System for Visually Impaired is an project aims to utilize electronic id technology to enable visually impaired persons to identify surrounding people in a social setting such as a conference. The exchange of information is the main enabler of the application, and the design of an efficient communication protocol among the resource-limited unsynchronized electronic id tags is the key to the entire system. Featuring CR2025 coin battery packed with limited power, adding to the fact that participants and their tags are all constantly moving, this communication protocol has to be able to establish synchronization and exchange information in the short time span when people walk passed each other while accomplishing this in a power efficient manner. This report highlights the design of this application-specific communication protocol, and compares its performance with other protocols considered but not chosen during the design process. Previous Infrastructure Social Networking Tags System for Visually Impaired project, an initiative in Harris Mobile Computing Lab in University of Florida, is a project sponsored by NSF. The scope of the project includes the hardware design of a brand new electronic id tag, the design and implementation of an application-specific communication/synchronization protocol between tags, and the end system (blind unit) that process collected information and present to visually impaired persons. The smart active electronic id tag hardware has a size of only 35mm x 29mm, featuring a low-power 32kHz PIC16F690 microcontroller, a low-power nrf24l01 chip running Wibree [1] short range radio. It operates with 2.2V to 3.0V power supply, and features a physical on/off switch, while the transmission power level can be controlled using software. Offering a short range radio transmission with maximum transmission rate of 1Mbps, the tag is designed to transmit information in bursts within a short range to ensure good power performance. Literature Survey Since the communication protocol of interest is application-specific, it is unlikely that a totally comparable protocol can be found and employed. But a particular data link layer/routing protocol from Motorola designed for sensor network nodes [2] address certain common aspects as our project. With the assumption that sensor nodes goes into sleep mode at majority of time and only wakes up periodically in order to conserve energy, Callaway described Mediation Device Protocol (MD) in which nodes take stochastic turns to be MD, the central synchronization manager, that records time differences between awaken time slots of each node, and synchronizes these nodes so they can be awake at the same time. This protocol results in long message latency and low system throughput, but it is suitable for non-real-time, low

2 data density applications such as environmental monitoring MAC protocol [3] introduces CSMA/CA basic protocol that utilizes carrier sensing, random backoff value and countdown during channel idleness to allow multiple wireless nodes to hit the airwave. An optional reservation scheme with RTS/CTS is provided to avoid collision, which is suitable for longer message (hence greater collision penalty) and higher node density. Motivation The MD protocol from Motorola is extremely efficient for non-real-time and low data density applications, and works well in ad-hoc fashion with resource-stricken sensor nodes. However, our target application requires a higher data transmission density. Although our application is not a real-time system, it does require information to be delivered to visually impaired persons in a timely fashion. On top of that, the high mobility of tags negates the benefit of establishing MD as the center of neighborhood synchronization, when persons wearing tags have a fair chance of roaming away before the next synchronization point MAC protocol provides some insights about sharing airwave between multiple nodes, but as WiFi is not used as the underlying communication module, it does not make sense to implement the whole protocol suite. It is also too costly a protocol to use with this hardware and on this application. A more application specific approach better suited to the hardware and resources available is needed. Technique (Solution) and Implementation The basic communication scheme for this protocol is described below. The protocol can be divided into two parts, the first concerns about the power-efficient scheduling of communication task of a single blind unit/single guest tag unit exchange; and the second concerns about single blind unit communicating with multiple guest tag units. Based on our preliminary study, the effective range of communication of our tags is 5 feet. Under a social setting, a well-visional person would take about 2 minutes to cross that distance, and it would take even longer for visually impaired persons. The periodic guest information solicitation is therefore set to be performed every 3 minutes (180 seconds). Every 180 seconds, the blind unit would broadcast a solicitation message piggybacked with the synchronization information. The guest tags, once received this solicitation, reply back with personal information at the specified synchronized transmission period. For blind unit to get all information about surrounding guests, we need to make sure at least one solicit request will hit the guest unit while it is in Rx mode. The designed protocol is shows as in Figure 1, where optimal x is calculated to minimize the cost function, which is the overall system power consumption, including both blind and guest units. For 1280 Byte solicit packet, it takes 10 ms to transmit, and the optimal listening period would be x = 1250 ms. 2

3 Solicit x Sleep Solicit Sleep Solicit Sleep y Collecting Period Blind Unit Sleep Listening Reply Guest Unit x 180 sec Figure 1. Communication Protocol y C Listening C Listening Sleep Blind Unit Sleep R Reply Data Random Delay R L Guest Units Figure 2. Communications MAC Protocol The collecting period on the blind unit y is yet to be decided at this point. The primary consideration for this decision relies on what kind of MAC protocol to be used and the associated time parameters when there are multiple guest units present. After evaluating several proposals, RTS/CTS reservation scheme, as shown in Figure 2, is chosen for its efficiency and simplicity. Each guest unit randomly pick a delay factor K less than 256, and waited K * 130 µs (carrier detect time) before sending out the RTS. Selecting K to be 256 gives us a probability of 83% that no collision would happen even if there are 10 tags trying to reply to the same solicitation request. If the guest unit senses there are transmissions in the air, it suspends the countdown of K, and resumes once the on-air signal is terminated. The blind unit listens to the incoming RTS or data transmission; if a RTS is received, it replies with CTS and waits for actual information to come; if actual data packets arrive without a previously cleared RTS, the data is discarded. Based on this RTS/CTS scheme, the length of collecting period y is set to ms. Analytical evaluation of this protocol will be shown in the results section. This protocol is currently being implemented on the actual electronic id tags and CCS compiler is chosen for its code efficiency, built-in functions, low cost and availability of convenient IDE. The focus of this report is on the analysis of the power efficiency of the designed protocol, and the full demo and implementation is beyond the scope. 3

4 Results For evaluation of the design, we compare the presented protocol to two baseline alternatives that were considered during the design and the implementation process as shown in Figure 3. Based on the data sheet of the microprocessor/transceiver used in the hardware, we know the following parameter for a fact mA of current need to be supplied to Transceiver when in Tx mode, 14 ma is needed for Rx mode. 2. In sleep mode (standby), only 32 µa would be supplied, and is considered ignorable because of the 3 order of differences. For the operation intended with the system, the effective transmission range is around 5 ft and the resulting propagation delay of less than 0.01 µs can be ignored. a. Remote Trigger b. Continuous Listening c. Periodic Announcement Listen Transmit Sleep Data Collect (Repeat of Fig 1) Figure 3. Communication Protocol Comparison The three protocols include remote trigger (Figure 3a), which would be the most efficient protocol, since the guest unit only wakes up when a solicitation request from the blind unit arrives. In practice, however, the power of the signal arrived is not strong enough to activate the trigger. Remote trigger protocol would serve as the lower bound of the power consumption evaluation. In Figure 3b, the continuous listening protocol makes guest unit continuously listening for the solicit request, allowing them to respond to the inquiry promptly. The continuous operation makes this an extremely expensive proposition, and it serves as an upper bound during the protocol design process. The power consumption in 3-minute period for these three protocols is reported in Table 1. Table 1. Whole-System Power Consumptions of Three Candidate Communication Protocols Protocol Remote Trigger Continuous Listening Periodic Announcement Power consumption 290 ms-ma 2.16 x 10 6 ms-ma ms-ma (1x) (~260,000x) (120x) For MAC protocol, we examined four different proposals, the random delay scheme, extended time slot scheme, centralized clock system and the RTS/CTS reservation scheme. Because the difference between current supplied to the transceiver in Rx and TX modes is only marginal in a short period of time and we assume the voltage supplied to the system is regulated at a constant level, the power consumption can be fairly accurately estimated solely by the time it takes to complete the multiple-tag data exchanges. Each of these four MAC protocols require each guest tag to pick a random delay value K, but they are 4

5 used differently. The random delay scheme is similar to the basic MAC protocol which delay transmissions based on a countdowns from K when sensing idle airwave. With 130 µs as the basic unit of delay, this scheme would take ms to complete one round, but there is a great chance collision would happen if tags cannot detect all transmissions in the air. This constraint does not satisfy the environment of the targeted application, hence is ruled out early in the design. The extended time slot scheme assign a 10 ms slot for each of the K (delay) value, and each guest tag would reply based on the randomly selected K value after listening for the idle airwave since the communication protocol described above allow different tags to be synchronized. Assuming reasonable clock drift on each tag and the blind unit, this scheme would work reasonably well, even in highly dense populated locality such as dance floor, only at most 17% of reply may collide, as the reliability of the reply rise sharply to more than 96% if there are only 5 tags trying to reply. This scheme, however, would need 2560 ms to complete, which is an order higher than any other schemes. The centralized clocked system make the blind unit send out clocked K number every 130 µs, and it works much like how patrons get a number tag in a busy post office, when send out reply only when their number is called. This scheme would take 228 ms to complete in the worst case, and avoids the problem of clock drifting as well as the packet collision. However, the blind unit needs to switch between Rx and Tx modes 256 times in a high frequency. The last MAC protocol, which is shown in Figure 2, is RTS/CTS reservation protocol. Used as optional bandwidth reservation scheme, each tag count down based on the random K value of 130 µs slots, when the countdown reaches 0, the guest unit send out a RTS, which is responded by the blind unit with CTS, and the information exchange ensues. In the worst case, this scheme takes 237 ms to complete the data exchange, and also has low probability for packet collision. Although the time it takes to complete the round is slightly higher than centralized clocked system, it is attractive also for its simplicity. Based on these two considerations, RTS/CTS reservation scheme is chosen as the MAC protocol. The discussion above is summarized in Table 2. Table 2. Time Required to Complete Multiple Data Exchange Four Candidate MAC Protocols MAC Protocol Random Delay Extended Slot Centralized Clock RTS/CTS Time Required (ms) Drawback All nodes need to Collision still possible, High frequency Collision of RTS hear all messages time consuming Rx/Tx modes still possible in the air flipping Conclusion and Future Directions Assistive systems for the visually impaired have been one of the major focuses for health care, wearable computer and intelligent environment communities. This project is different, however, because it focuses on providing assistance in enhancing their social interactions. One of the keys to the success of this project is to design a communication/synchronization protocol that can handle unsynchronized tags passing 5

6 one another in fleeting moments without wasting lots of energy. This project considers hardware, software and situational constraints and evaluates multiple proposals to come up with the final design, and analytically evaluate the costs and benefits of these proposals. The fully functional prototype system is expected some time in May A usability study involving visually impaired subjects is scheduled to take place starting from June We hope to evaluate the real benefit this infrastructure-less system can provide in a realistic setting following the preliminary usability study. Acknowledgement I would like to thank Dr. Mishra for his suggestions regarding the direction and points of consideration on this protocol design project. I would also like to express my gratitude to Dr. Helal for his leadership and continuous support on the overall Social Networking Tags System for Visually Impaired project and the funding agency NSF. Many thanks also go to my collaborators Mr. Ed Koush and Mr. Raja Bose. References 1. Wibree Open Industry Initiative, Wibree Data Sheet, 2. E. Callaway, Wireless sensor networks: architectures and protocols, Chapter 1 7, Auerbach Publications, IEEE , 1999 Edition (ISO/IEC :1999) IEEE Standards for Information Technology Telecommunications and Information Exchange Between Systems Local and Metropolitan Area Network Specific Requirements Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specification, 6

SENSOR-MAC CASE STUDY

SENSOR-MAC CASE STUDY SENSOR-MAC CASE STUDY Periodic Listen and Sleep Operations One of the S-MAC design objectives is to reduce energy consumption by avoiding idle listening. This is achieved by establishing low-duty-cycle

More information

MAC in /20/06

MAC in /20/06 MAC in 802.11 2/20/06 MAC Multiple users share common medium. Important issues: Collision detection Delay Fairness Hidden terminals Synchronization Power management Roaming Use 802.11 as an example to

More information

Medium Access Control (MAC) Protocols for Ad hoc Wireless Networks -IV

Medium Access Control (MAC) Protocols for Ad hoc Wireless Networks -IV Medium Access Control (MAC) Protocols for Ad hoc Wireless Networks -IV CS: 647 Advanced Topics in Wireless Networks Drs. Baruch Awerbuch & Amitabh Mishra Department of Computer Science Johns Hopkins University

More information

Presented by: Murad Kaplan

Presented by: Murad Kaplan Presented by: Murad Kaplan Introduction. Design of SCP-MAC. Lower Bound of Energy Performance with Periodic Traffic. Protocol Implementation. Experimental Evaluation. Related Work. 2 Energy is a critical

More information

CSMA based Medium Access Control for Wireless Sensor Network

CSMA based Medium Access Control for Wireless Sensor Network CSMA based Medium Access Control for Wireless Sensor Network H. Hoang, Halmstad University Abstract Wireless sensor networks bring many challenges on implementation of Medium Access Control protocols because

More information

Lesson 2-3: The IEEE x MAC Layer

Lesson 2-3: The IEEE x MAC Layer Module 2: Establishing Wireless Connectivity Lesson 2-3: The IEEE 802.11x MAC Layer Lesson Overview This lesson describes basic IEEE 802.11x MAC operation, beginning with an explanation of contention schemes

More information

Performance and Comparison of Energy Efficient MAC Protocol in Wireless Sensor Network

Performance and Comparison of Energy Efficient MAC Protocol in Wireless Sensor Network www.ijecs.in International Journal Of Engineering And Computer Science ISSN:2319-7242 Volume 4 Issue 3 March 2015, Page No. 10652-10656 Performance and Comparison of Energy Efficient MAC Protocol in Wireless

More information

Reservation Packet Medium Access Control for Wireless Sensor Networks

Reservation Packet Medium Access Control for Wireless Sensor Networks Reservation Packet Medium Access Control for Wireless Sensor Networks Hengguang Li and Paul D Mitchell Abstract - This paper introduces the Reservation Packet Medium Access Control (RP-MAC) protocol for

More information

R-MAC: An Energy-Efficient MAC Protocol for Underwater Sensor Networks

R-MAC: An Energy-Efficient MAC Protocol for Underwater Sensor Networks R-MAC: An Energy-Efficient MAC Protocol for Underwater Sensor Networks Peng Xie and Jun-Hong Cui UCONN CSE Technical Report: UbiNet-TR06-06 Last Update: June 2007 Abstract Underwater sensor networks are

More information

MAC Essentials for Wireless Sensor Networks

MAC Essentials for Wireless Sensor Networks MAC Essentials for Wireless Sensor Networks Abdelmalik Bachir, Mischa Dohler, Senior Member, IEEE, Thomas Watteyne, Member, IEEE, and Kin K. Leung, Fellow, IEEE Medium access control Part of the link layer

More information

ECE 4450:427/527 - Computer Networks Spring 2017

ECE 4450:427/527 - Computer Networks Spring 2017 ECE 4450:427/527 - Computer Networks Spring 2017 Dr. Nghi Tran Department of Electrical & Computer Engineering Lecture 5.5: Ethernet Dr. Nghi Tran (ECE-University of Akron) ECE 4450:427/527 Computer Networks

More information

Wireless Networks (MAC)

Wireless Networks (MAC) 802.11 Wireless Networks (MAC) Kate Ching-Ju Lin ( 林靖茹 ) Academia Sinica 2016.03.18 CSIE, NTU Reference 1. A Technical Tutorial on the IEEE 802.11 Protocol By Pablo Brenner online: http://www.sss-mag.com/pdf/802_11tut.pdf

More information

IEEE , Token Rings. 10/11/06 CS/ECE UIUC, Fall

IEEE , Token Rings. 10/11/06 CS/ECE UIUC, Fall IEEE 802.11, Token Rings 10/11/06 CS/ECE 438 - UIUC, Fall 2006 1 Medium Access Control Wireless channel is a shared medium Need access control mechanism to avoid interference Why not CSMA/CD? 10/11/06

More information

Delay Analysis of ML-MAC Algorithm For Wireless Sensor Networks

Delay Analysis of ML-MAC Algorithm For Wireless Sensor Networks Delay Analysis of ML-MAC Algorithm For Wireless Sensor Networks Madhusmita Nandi School of Electronics Engineering, KIIT University Bhubaneswar-751024, Odisha, India ABSTRACT The present work is to evaluate

More information

Improving IEEE Power Saving Mechanism

Improving IEEE Power Saving Mechanism 1 Improving IEEE 82.11 Power Saving Mechanism Eun-Sun Jung 1 and Nitin H. Vaidya 2 1 Dept. of Computer Science, Texas A&M University, College Station, TX 77843, USA Email: esjung@cs.tamu.edu 2 Dept. of

More information

Department of Electrical and Computer Systems Engineering

Department of Electrical and Computer Systems Engineering Department of Electrical and Computer Systems Engineering Technical Report MECSE-6-2006 Medium Access Control (MAC) Schemes for Quality of Service (QoS) provision of Voice over Internet Protocol (VoIP)

More information

Lecture 23 Overview. Last Lecture. This Lecture. Next Lecture ADSL, ATM. Wireless Technologies (1) Source: chapters 6.2, 15

Lecture 23 Overview. Last Lecture. This Lecture. Next Lecture ADSL, ATM. Wireless Technologies (1) Source: chapters 6.2, 15 Lecture 23 Overview Last Lecture ADSL, ATM This Lecture Wireless Technologies (1) Wireless LAN, CSMA/CA, Bluetooth Source: chapters 6.2, 15 Next Lecture Wireless Technologies (2) Source: chapter 16, 19.3

More information

Data Communications. Data Link Layer Protocols Wireless LANs

Data Communications. Data Link Layer Protocols Wireless LANs Data Communications Data Link Layer Protocols Wireless LANs Wireless Networks Several different types of communications networks are using unguided media. These networks are generally referred to as wireless

More information

Getting Connected (Chapter 2 Part 4) Networking CS 3470, Section 1 Sarah Diesburg

Getting Connected (Chapter 2 Part 4) Networking CS 3470, Section 1 Sarah Diesburg Getting Connected (Chapter 2 Part 4) Networking CS 3470, Section 1 Sarah Diesburg Five Problems Encoding/decoding Framing Error Detection Error Correction Media Access Five Problems Encoding/decoding Framing

More information

A PERFORMANCE EVALUATION OF YMAC A MEDIUM ACCESS PROTOCOL FOR WSN

A PERFORMANCE EVALUATION OF YMAC A MEDIUM ACCESS PROTOCOL FOR WSN A PERFORMANCE EVALUATION OF YMAC A MEDIUM ACCESS PROTOCOL FOR WSN Albeiro Cortés Cabezas and José de Jesús Salgado Patrón Department of Electronic Engineering, Surcolombiana University, Neiva, Colombia

More information

Collision Free and Energy Efficient MAC protocol for Wireless Networks

Collision Free and Energy Efficient MAC protocol for Wireless Networks 110 IJCSNS International Journal of Computer Science and Network Security, VOL.7 No.9, September 2007 Collision Free and Energy Efficient MAC protocol for Wireless Networks Muhammad Ali Malik, Dongha Shin

More information

MAC LAYER. Murat Demirbas SUNY Buffalo

MAC LAYER. Murat Demirbas SUNY Buffalo MAC LAYER Murat Demirbas SUNY Buffalo MAC categories Fixed assignment TDMA (Time Division), CDMA (Code division), FDMA (Frequency division) Unsuitable for dynamic, bursty traffic in wireless networks Random

More information

Local Area Networks NETW 901

Local Area Networks NETW 901 Local Area Networks NETW 901 Lecture 4 Wireless LAN Course Instructor: Dr.-Ing. Maggie Mashaly maggie.ezzat@guc.edu.eg C3.220 1 Contents What is a Wireless LAN? Applications and Requirements Transmission

More information

ECE 4450:427/527 - Computer Networks Spring 2017

ECE 4450:427/527 - Computer Networks Spring 2017 ECE 4450:427/527 - Computer Networks Spring 2017 Dr. Nghi Tran Department of Electrical & Computer Engineering Lecture 5.4: Multiple Access Protocols Dr. Nghi Tran (ECE-University of Akron) ECE 4450:427/527

More information

Can Multiple Subchannels Improve the Delay Performance of RTS/CTS-based MAC Schemes?

Can Multiple Subchannels Improve the Delay Performance of RTS/CTS-based MAC Schemes? Can Multiple Subchannels Improve the Delay Performance of RTS/CTS-based MAC Schemes? By: Jing Deng, Yunghsiang S. Han, and Sanjeev R. Kulkarni. J. Deng, Y. S. Han, and S. R. Kulkarni, "Can Multiple Subchannels

More information

LECTURE PLAN. Script. Introduction about MAC Types o ALOHA o CSMA o CSMA/CD o CSMA/CA

LECTURE PLAN. Script. Introduction about MAC Types o ALOHA o CSMA o CSMA/CD o CSMA/CA Course- B.Sc. Applied Physical Science (Computer Science) Year- IIIrd, Sem- Vth Subject Computer Science Paper- XVIIth, Computer Networks Lecture -11 Lecture Title- Medium Access Layer Script Today in

More information

Lecture 16: QoS and "

Lecture 16: QoS and Lecture 16: QoS and 802.11" CSE 123: Computer Networks Alex C. Snoeren HW 4 due now! Lecture 16 Overview" Network-wide QoS IntServ DifServ 802.11 Wireless CSMA/CA Hidden Terminals RTS/CTS CSE 123 Lecture

More information

Wireless Networks (MAC) Kate Ching-Ju Lin ( 林靖茹 ) Academia Sinica

Wireless Networks (MAC) Kate Ching-Ju Lin ( 林靖茹 ) Academia Sinica 802.11 Wireless Networks (MAC) Kate Ching-Ju Lin ( 林靖茹 ) Academia Sinica Reference 1. A Technical Tutorial on the IEEE 802.11 Protocol By Pablo Brenner online: http://www.sss-mag.com/pdf/802_11tut.pdf

More information

AN EFFICIENT MAC PROTOCOL FOR SUPPORTING QOS IN WIRELESS SENSOR NETWORKS

AN EFFICIENT MAC PROTOCOL FOR SUPPORTING QOS IN WIRELESS SENSOR NETWORKS AN EFFICIENT MAC PROTOCOL FOR SUPPORTING QOS IN WIRELESS SENSOR NETWORKS YINGHUI QIU School of Electrical and Electronic Engineering, North China Electric Power University, Beijing, 102206, China ABSTRACT

More information

standards like IEEE [37], IEEE [38] or IEEE [39] do not consider

standards like IEEE [37], IEEE [38] or IEEE [39] do not consider Chapter 5 IEEE 802.15.4 5.1 Introduction Wireless Sensor Network(WSN) is resource constrained network developed specially targeting applications having unattended network for long time. Such a network

More information

WIRELESS sensor networking is an emerging technology

WIRELESS sensor networking is an emerging technology USC/ISI TECHNICAL REPORT ISI-TR-567, JANUARY 2003 1 Medium Access Control with Coordinated, Adaptive Sleeping for Wireless Sensor Networks Wei Ye, John Heidemann, Deborah Estrin Abstract This paper proposes

More information

CS 43: Computer Networks Media Access. Kevin Webb Swarthmore College November 30, 2017

CS 43: Computer Networks Media Access. Kevin Webb Swarthmore College November 30, 2017 CS 43: Computer Networks Media Access Kevin Webb Swarthmore College November 30, 2017 Multiple Access Links & Protocols Two classes of links : point-to-point dial-up access link between Ethernet switch,

More information

IEEE Medium Access Control. Medium Access Control

IEEE Medium Access Control. Medium Access Control IEEE 802.11 Medium Access Control EECS3214 3 April 2018 Medium Access Control reliable data delivery access control MAC layer covers three functional areas: security 2 1 MAC Requirements To avoid interference

More information

Mohamed Khedr.

Mohamed Khedr. Mohamed Khedr http://webmail.aast.edu/~khedr Tentatively Week 1 Week 2 Week 3 Week 4 Week 5 Week 6 Week 7 Week 8 Week 9 Week 10 Week 11 Week 12 Week 13 Week 14 Week 15 Overview Packet Switching IP addressing

More information

Geographical Routing Algorithms In Asynchronous Wireless Sensor Network

Geographical Routing Algorithms In Asynchronous Wireless Sensor Network Geographical Routing Algorithms In Asynchronous Wireless Sensor Network Vaishali.S.K, N.G.Palan Electronics and telecommunication, Cummins College of engineering for women Karvenagar, Pune, India Abstract-

More information

College of Computer and Information Sciences Department of Computer Engineering CEN444 Computer Networks Midterm 2 Exam Second Semester 1434/1435

College of Computer and Information Sciences Department of Computer Engineering CEN444 Computer Networks Midterm 2 Exam Second Semester 1434/1435 College of Computer and Information Sciences Department of Computer Engineering CEN444 Computer Networks Midterm 2 Exam Second Semester 1434/1435 Student Name ID Time Allowed: 2.0 Hours. Closed Book, Closed

More information

Computer Communication III

Computer Communication III Computer Communication III Wireless Media Access IEEE 802.11 Wireless LAN Advantages of Wireless LANs Using the license free ISM band at 2.4 GHz no complicated or expensive licenses necessary very cost

More information

CS 43: Computer Networks. 27: Media Access Contd. December 3, 2018

CS 43: Computer Networks. 27: Media Access Contd. December 3, 2018 CS 43: Computer Networks 27: Media Access Contd. December 3, 2018 Last Class The link layer provides lots of functionality: addressing, framing, media access, error checking could be used independently

More information

Outline. MAC (Medium Access Control) General MAC Requirements. Typical MAC protocols. Typical MAC protocols

Outline. MAC (Medium Access Control) General MAC Requirements. Typical MAC protocols. Typical MAC protocols Outline Medium ccess ontrol With oordinated daptive Sleeping for Wireless Sensor Networks Presented by: rik rooks Introduction to M S-M Overview S-M Evaluation ritique omparison to MW Washington University

More information

Advanced Networking Technologies

Advanced Networking Technologies Advanced Networking Technologies Chapter 4 Medium Access Control Protocols (Acknowledgement: These slides have been prepared by Prof. Dr. Holger Karl) Advanced Networking (SS 16): 04 Medium Access Control

More information

Impact of IEEE MAC Packet Size on Performance of Wireless Sensor Networks

Impact of IEEE MAC Packet Size on Performance of Wireless Sensor Networks IOSR Journal of Electronics and Communication Engineering (IOSR-JECE) e-issn: 2278-2834,p- ISSN: 2278-8735.Volume 10, Issue 3, Ver. IV (May - Jun.2015), PP 06-11 www.iosrjournals.org Impact of IEEE 802.11

More information

Keywords T MAC protocol, reduction function, wsn, contention based mac protocols, energy efficiency; Fig 1. Listen and sleep cycle in S MAC protocol

Keywords T MAC protocol, reduction function, wsn, contention based mac protocols, energy efficiency; Fig 1. Listen and sleep cycle in S MAC protocol Volume 3, Issue 6, June 2013 ISSN: 2277 128X International Journal of Advanced Research in Computer Science and Software Engineering Research Paper Available online at: www.ijarcsse.com Introduction to

More information

Medium Access Control in Wireless Sensor Networks

Medium Access Control in Wireless Sensor Networks Medium Access Control in Wireless Sensor Networks Davide Quaglia, Damiano Carra LIVELLO DATALINK 2 1 Goals Reliable and efficient communication between two nodes on the same physical medium Cable (Wired)

More information

Optional Point Coordination Function (PCF)

Optional Point Coordination Function (PCF) Optional Point Coordination Function (PCF) Time Bounded / Async Contention Free Service PCF Optional DCF (CSMA/CA ) Async Contention Service MAC PHY Contention Free Service uses Point Coordination Function

More information

Analysis of Throughput and Energy Efficiency in the IEEE Wireless Local Area Networks using Constant backoff Window Algorithm

Analysis of Throughput and Energy Efficiency in the IEEE Wireless Local Area Networks using Constant backoff Window Algorithm International Journal of Computer Applications (975 8887) Volume 6 No.8, July Analysis of Throughput and Energy Efficiency in the IEEE 8. Wireless Local Area Networks using Constant backoff Window Algorithm

More information

Embedded Internet and the Internet of Things WS 12/13

Embedded Internet and the Internet of Things WS 12/13 Embedded Internet and the Internet of Things WS 12/13 4. MAC Protocols Prof. Dr. Mesut Güneş Distributed, embedded Systems (DES) Institute of Computer Science Freie Universität Berlin Prof. Dr. Mesut Güneş

More information

Medium Access Control in Wireless IoT. Davide Quaglia, Damiano Carra

Medium Access Control in Wireless IoT. Davide Quaglia, Damiano Carra Medium Access Control in Wireless IoT Davide Quaglia, Damiano Carra LIVELLO DATALINK 2 Goals Reliable and efficient communication between two nodes on the same physical medium Cable (Wired) Wireless Assumptions

More information

15-441: Computer Networking. Wireless Networking

15-441: Computer Networking. Wireless Networking 15-441: Computer Networking Wireless Networking Outline Wireless Challenges 802.11 Overview Link Layer Ad-hoc Networks 2 Assumptions made in Internet Host are (mostly) stationary Address assignment, routing

More information

Author: Bill Buchanan. Wireless LAN. Unit 2: Wireless Fundamentals

Author: Bill Buchanan. Wireless LAN. Unit 2: Wireless Fundamentals Wireless LAN Unit 2: Wireless Fundamentals Wireless connections which technology? Areas covered: Basic radio parameters. This area covers the main type of wireless communications. IEEE 802.11b issues.

More information

Announcements: Assignment 4 due now Lab 4 due next Tuesday Assignment 5 posted, due next Thursday

Announcements: Assignment 4 due now Lab 4 due next Tuesday Assignment 5 posted, due next Thursday ECE/CS 372 introduction to computer networks Lecture 15 Announcements: Assignment 4 due now Lab 4 due next Tuesday Assignment 5 posted, due next Thursday Credit for lecture slides to Professor Bechir Hamdaoui

More information

Implementation of a Wake-up Radio Cross-Layer Protocol in OMNeT++ / MiXiM

Implementation of a Wake-up Radio Cross-Layer Protocol in OMNeT++ / MiXiM Implementation of a Wake-up Radio Cross-Layer Protocol in OMNeT++ / MiXiM Jean Lebreton and Nour Murad University of La Reunion, LE2P 40 Avenue de Soweto, 97410 Saint-Pierre Email: jean.lebreton@univ-reunion.fr

More information

Chapter 4. The Medium Access Control Sublayer. Points and Questions to Consider. Multiple Access Protocols. The Channel Allocation Problem.

Chapter 4. The Medium Access Control Sublayer. Points and Questions to Consider. Multiple Access Protocols. The Channel Allocation Problem. Dynamic Channel Allocation in LANs and MANs Chapter 4 The Medium Access Control Sublayer 1. Station Model. 2. Single Channel Assumption. 3. Collision Assumption. 4. (a) Continuous Time. (b) Slotted Time.

More information

RT-Link: A global time-synchronized link protocol for sensor networks Anthony Rowe, Rahul Mangharam, Raj Rajkumar

RT-Link: A global time-synchronized link protocol for sensor networks Anthony Rowe, Rahul Mangharam, Raj Rajkumar RT-Link: A global time-synchronized link protocol for sensor networks Anthony Rowe, Rahul Mangharam, Raj Rajkumar Papa Alioune Ly, Joel Alloh, Carl Hedari, Tom Reynaert Outline Introduction Design of the

More information

Energy Efficient MAC Protocols Design for Wireless Sensor Networks

Energy Efficient MAC Protocols Design for Wireless Sensor Networks Energy Efficient MAC Protocols Design for Wireless Sensor Networks Francesco Chiti*, Michele Ciabatti*, Giovanni Collodi, Davide Di Palma*, Romano Fantacci *, Antonio Manes *Dipartimento di Elettronica

More information

Mobile and Sensor Systems

Mobile and Sensor Systems Mobile and Sensor Systems Lecture 2: Mobile Medium Access Control Protocols and Wireless Systems Dr Cecilia Mascolo In this lecture We will describe medium access control protocols and wireless systems

More information

Networking Sensors, I

Networking Sensors, I Networking Sensors, I Sensing Networking Leonidas Guibas Stanford University Computation CS428 Networking Sensors Networking is a crucial capability for sensor networks -- networking allows: Placement

More information

Lecture 12 December 04, Wireless Access. Graduate course in Communications Engineering. University of Rome La Sapienza. Rome, Italy

Lecture 12 December 04, Wireless Access. Graduate course in Communications Engineering. University of Rome La Sapienza. Rome, Italy Lecture 12 December 04, 2017 Wireless Access Graduate course in Communications Engineering University of Rome La Sapienza Rome, Italy 2017-2018 Random Medium Access Control Part II - CSMA and Collision

More information

Sleep/Wake Aware Local Monitoring (SLAM)

Sleep/Wake Aware Local Monitoring (SLAM) Sleep/Wake Aware Local Monitoring (SLAM) Issa Khalil, Saurabh Bagchi, Ness Shroff Dependable Computing Systems Lab (DCSL) & Center for Wireless Systems and Applications (CWSA) School of Electrical and

More information

Wireless Sensor Networks

Wireless Sensor Networks Wireless Sensor Networks c.buratti@unibo.it +39 051 20 93147 Office Hours: Tuesday 3 5 pm @ Main Building, second floor Credits: 6 Ouline 1. WS(A)Ns Introduction 2. Applications 3. Energy Efficiency Section

More information

An Efficient Scheduling Scheme for High Speed IEEE WLANs

An Efficient Scheduling Scheme for High Speed IEEE WLANs An Efficient Scheduling Scheme for High Speed IEEE 802.11 WLANs Juki Wirawan Tantra, Chuan Heng Foh, and Bu Sung Lee Centre of Muldia and Network Technology School of Computer Engineering Nanyang Technological

More information

Wireless Local Area Network (IEEE )

Wireless Local Area Network (IEEE ) Wireless Local Area Network (IEEE 802.11) -IEEE 802.11 Specifies a single Medium Access Control (MAC) sublayer and 3 Physical Layer Specifications. Stations can operate in two configurations : Ad-hoc mode

More information

AN ANALYSIS OF THE MODIFIED BACKOFF MECHANISM FOR IEEE NETWORKS

AN ANALYSIS OF THE MODIFIED BACKOFF MECHANISM FOR IEEE NETWORKS AN ANALYSIS OF THE MODIFIED BACKOFF MECHANISM FOR IEEE 802.11 NETWORKS Marek Natkaniec, Andrzej R. Pach Department of Telecommunications University of Mining and Metallurgy al. Mickiewicza 30, 30-059 Cracow

More information

ABSTRACT. Physical Implementation of Synchronous Duty-Cycling MAC Protocols: Experiences and Evaluation. Wei-Cheng Xiao

ABSTRACT. Physical Implementation of Synchronous Duty-Cycling MAC Protocols: Experiences and Evaluation. Wei-Cheng Xiao ABSTRACT Physical Implementation of Synchronous Duty-Cycling MAC Protocols: Experiences and Evaluation by Wei-Cheng Xiao Energy consumption and network latency are important issues in wireless sensor networks.

More information

Implementation of an Adaptive MAC Protocol in WSN using Network Simulator-2

Implementation of an Adaptive MAC Protocol in WSN using Network Simulator-2 Implementation of an Adaptive MAC Protocol in WSN using Network Simulator-2 1 Suresh, 2 C.B.Vinutha, 3 Dr.M.Z Kurian 1 4 th Sem, M.Tech (Digital Electronics), SSIT, Tumkur 2 Lecturer, Dept.of E&C, SSIT,

More information

Multi-Channel MAC for Ad Hoc Networks: Handling Multi-Channel Hidden Terminals Using A Single Transceiver

Multi-Channel MAC for Ad Hoc Networks: Handling Multi-Channel Hidden Terminals Using A Single Transceiver Multi-Channel MAC for Ad Hoc Networks: Handling Multi-Channel Hidden Terminals Using A Single Transceiver Jungmin So Dept. of Computer Science, and Coordinated Science Laboratory University of Illinois

More information

6.9 Summary. 11/20/2013 Wireless and Mobile Networks (SSL) 6-1. Characteristics of selected wireless link standards a, g point-to-point

6.9 Summary. 11/20/2013 Wireless and Mobile Networks (SSL) 6-1. Characteristics of selected wireless link standards a, g point-to-point Chapter 6 outline 6.1 Introduction Wireless 6.2 Wireless links, characteristics CDMA 6.3 IEEE 802.11 wireless LANs ( wi-fi ) 6.4 Cellular Internet Access architecture standards (e.g., GSM) Mobility 6.5

More information

Wireless Medium Access Control Protocols

Wireless Medium Access Control Protocols Wireless Medium Access Control Protocols Telecomunicazioni Undergraduate course in Electrical Engineering University of Rome La Sapienza Rome, Italy 2007-2008 Classification of wireless MAC protocols Wireless

More information

Wireless Sensor Networks 8th Lecture

Wireless Sensor Networks 8th Lecture Wireless Sensor Networks 8th Lecture 21.11.2006 Christian Schindelhauer schindel@informatik.uni-freiburg.de 1 Media Access Control (MAC) Controlling when to send a packet and when to listen for a packet

More information

ECEN 5032 Data Networks Medium Access Control Sublayer

ECEN 5032 Data Networks Medium Access Control Sublayer ECEN 5032 Data Networks Medium Access Control Sublayer Peter Mathys mathys@colorado.edu University of Colorado, Boulder c 1996 2005, P. Mathys p.1/35 Overview (Sub)networks can be divided into two categories:

More information

Medium Access Control in Wireless Sensor Networks

Medium Access Control in Wireless Sensor Networks Medium Access Control in Wireless Sensor Networks Davide Quaglia, Damiano Carra LIVELLO DATALINK 2 1 Goals Reliable and efficient communication between two nodes on the same physical medium Cable (Wired)

More information

An Experimental Study of Network Performance Impact of Increased Latency in SDR

An Experimental Study of Network Performance Impact of Increased Latency in SDR An Experimental Study of Network Performance Impact of Increased Latency in SDR Thomas Schmid Oussama Sekkat Mani B. Srivastava - Wintech workshop was started with the Keynote from Eric Blossom on GNU

More information

CSE 461: Multiple Access Networks. This Lecture

CSE 461: Multiple Access Networks. This Lecture CSE 461: Multiple Access Networks This Lecture Key Focus: How do multiple parties share a wire? This is the Medium Access Control (MAC) portion of the Link Layer Randomized access protocols: 1. Aloha 2.

More information

Medium Access Control

Medium Access Control Medium Access Control Fundamental Problem N nodes in vicinity want to transmit (to, say, N other nodes). How to do this interference free? Interference free means SINR Otherwise, we say that packets collide.

More information

P B 1-P B ARRIVE ATTEMPT RETRY 2 1-(1-P RF ) 2 1-(1-P RF ) 3 1-(1-P RF ) 4. Figure 1: The state transition diagram for FBR.

P B 1-P B ARRIVE ATTEMPT RETRY 2 1-(1-P RF ) 2 1-(1-P RF ) 3 1-(1-P RF ) 4. Figure 1: The state transition diagram for FBR. 1 Analytical Model In this section, we will propose an analytical model to investigate the MAC delay of FBR. For simplicity, a frame length is normalized as a time unit (slot). 1.1 State Transition of

More information

Medium Access Control. IEEE , Token Rings. CSMA/CD in WLANs? Ethernet MAC Algorithm. MACA Solution for Hidden Terminal Problem

Medium Access Control. IEEE , Token Rings. CSMA/CD in WLANs? Ethernet MAC Algorithm. MACA Solution for Hidden Terminal Problem Medium Access Control IEEE 802.11, Token Rings Wireless channel is a shared medium Need access control mechanism to avoid interference Why not CSMA/CD? 9/15/06 CS/ECE 438 - UIUC, Fall 2006 1 9/15/06 CS/ECE

More information

MULTIPLE ACCESS PROTOCOLS 2. 1

MULTIPLE ACCESS PROTOCOLS 2. 1 MULTIPLE ACCESS PROTOCOLS AND WIFI 1 MULTIPLE ACCESS PROTOCOLS 2. 1 MULTIPLE ACCESS LINKS, PROTOCOLS Two types of links : point-to-point broadcast (shared wire or medium) POINT-TO-POINT PPP for dial-up

More information

QoS Challenges and QoS-Aware MAC Protocols in Wireless Sensor Networks

QoS Challenges and QoS-Aware MAC Protocols in Wireless Sensor Networks QoS Challenges and QoS-Aware MAC Protocols in Wireless Sensor Networks S. Shiney Lillia PG Student, Department of Computer Science and Engineering, National Institute of Technology Puducherry, Puducherry,

More information

Medium Access Control in Wireless Networks

Medium Access Control in Wireless Networks Medium Access Control in Wireless Networks Prof. Congduc Pham http://www.univ-pau.fr/~cpham Université de Pau, France MAC layer Routing protocols Medium Acces Control IEEE 802.X MAC GSM (2G) Channels Downlink

More information

Numerical Analysis of IEEE Broadcast Scheme in Multihop Wireless Ad Hoc Networks

Numerical Analysis of IEEE Broadcast Scheme in Multihop Wireless Ad Hoc Networks Numerical Analysis of IEEE 802.11 Broadcast Scheme in Multihop Wireless Ad Hoc Networks Jong-Mu Choi 1, Jungmin So 2, and Young-Bae Ko 1 1 School of Information and Computer Engineering Ajou University,

More information

Computer Network Fundamentals Spring Week 3 MAC Layer Andreas Terzis

Computer Network Fundamentals Spring Week 3 MAC Layer Andreas Terzis Computer Network Fundamentals Spring 2008 Week 3 MAC Layer Andreas Terzis Outline MAC Protocols MAC Protocol Examples Channel Partitioning TDMA/FDMA Token Ring Random Access Protocols Aloha and Slotted

More information

CMPE 257: Wireless and Mobile Networking

CMPE 257: Wireless and Mobile Networking CMPE 257: Wireless and Mobile Networking Katia Obraczka Computer Engineering UCSC Baskin Engineering Lecture 3 CMPE 257 Winter'11 1 Announcements Accessing secure part of the class Web page: User id: cmpe257.

More information

CHAPTER 2 WIRELESS SENSOR NETWORKS AND NEED OF TOPOLOGY CONTROL

CHAPTER 2 WIRELESS SENSOR NETWORKS AND NEED OF TOPOLOGY CONTROL WIRELESS SENSOR NETWORKS AND NEED OF TOPOLOGY CONTROL 2.1 Topology Control in Wireless Sensor Networks Network topology control is about management of network topology to support network-wide requirement.

More information

By Ambuj Varshney & Akshat Logar

By Ambuj Varshney & Akshat Logar By Ambuj Varshney & Akshat Logar Wireless operations permits services, such as long range communications, that are impossible or impractical to implement with the use of wires. The term is commonly used

More information

Enhanced Power Saving Scheme for IEEE DCF Based Wireless Networks

Enhanced Power Saving Scheme for IEEE DCF Based Wireless Networks Enhanced Power Saving Scheme for IEEE 802.11 DCF Based Wireless Networks Jong-Mu Choi, Young-Bae Ko, and Jai-Hoon Kim Graduate School of Information and Communication Ajou University, Republic of Korea

More information

CSE 461: Wireless Networks

CSE 461: Wireless Networks CSE 461: Wireless Networks Wireless IEEE 802.11 A physical and multiple access layer standard for wireless local area networks (WLAN) Ad Hoc Network: no servers or access points Infrastructure Network

More information

Enhancements and Performance Evaluation of Wireless Local Area Networks

Enhancements and Performance Evaluation of Wireless Local Area Networks Enhancements and Performance Evaluation of Wireless Local Area Networks Jiaqing Song and Ljiljana Trajkovic Communication Networks Laboratory Simon Fraser University Burnaby, BC, Canada E-mail: {jsong,

More information

CS 3640: Introduction to Networks and Their Applications

CS 3640: Introduction to Networks and Their Applications CS 3640: Introduction to Networks and Their Applications Fall 2018, Lecture 7: The Link Layer II Medium Access Control Protocols Instructor: Rishab Nithyanand Teaching Assistant: Md. Kowsar Hossain 1 You

More information

Wireless and Mobile Networks

Wireless and Mobile Networks Wireless and Mobile Networks Raj Jain Washington University in Saint Louis Saint Louis, MO 63130 Jain@wustl.edu Audio/Video recordings of this lecture are available on-line at: http://www.cse.wustl.edu/~jain/cse473-11/

More information

AMAC: Traffic-Adaptive Sensor Network MAC Protocol through Variable Duty-Cycle Operations

AMAC: Traffic-Adaptive Sensor Network MAC Protocol through Variable Duty-Cycle Operations AMAC: Traffic-Adaptive Sensor Network MAC Protocol through Variable Duty-Cycle Operations Sang Hoon Lee, Joon Ho Park, and Lynn Choi Department of Electronics and Computer Engineering Korea University

More information

Principles of Wireless Sensor Networks. Medium Access Control and IEEE

Principles of Wireless Sensor Networks. Medium Access Control and IEEE http://www.ee.kth.se/~carlofi/teaching/pwsn-2011/wsn_course.shtml Lecture 7 Stockholm, November 8, 2011 Medium Access Control and IEEE 802.15.4 Royal Institute of Technology - KTH Stockholm, Sweden e-mail:

More information

UNIT IV. Data link layer protocols. Prof.Prasad S.Halgaonkar

UNIT IV. Data link layer protocols. Prof.Prasad S.Halgaonkar UNIT IV Data link layer protocols Link Layer Frame synchronization. Data are sent in blocks called frames. The beginning and end of each frame must be recognized. Flow control. The sending station must

More information

CMPE 257: Wireless and Mobile Networking

CMPE 257: Wireless and Mobile Networking CMPE 257: Wireless and Mobile Networking Katia Obraczka Computer Engineering UCSC Baskin Engineering Lecture 3 CMPE 257 Spring'15 1 Next week Announcements April 14: ICN (Spencer Sevilla) April 16: DTN

More information

Ferry Route Design with MAC Protocol in Delay Tolerant Networks

Ferry Route Design with MAC Protocol in Delay Tolerant Networks Ferry Route Design with MAC Protocol in Delay Tolerant Networks Chaitra T K 1, Dr A S Poornima Ph.D 2 1 Student, Department of Computer Science and Engineering, Siddaganga Institute of Technology, Tumkur

More information

Exercises of lecture Wireless Sensor Networks Winter 2006/2007 Sheet 4

Exercises of lecture Wireless Sensor Networks Winter 2006/2007 Sheet 4 Christian Schindelhauer Freiburg, 26 Nov 2006 Due until 28 Nov 2006 Exercises of lecture Wireless Sensor Networks Winter 2006/2007 Sheet 4 SECTION 1: Wireless Sensor Transceiver, Energy 1. Energy is limited

More information

CSMA/IC: A New Class of Collision free MAC Protocols for Ad Hoc Wireless Networks

CSMA/IC: A New Class of Collision free MAC Protocols for Ad Hoc Wireless Networks CSMA/IC: A New Class of Collision free MAC Protocols for Ad Hoc Wireless Networks Tiantong You (you@cs.queensu.ca) Department of Computing and Information Science Chi-Hsiang Yeh (yeh@ece.queensu.ca) Department

More information

Computational Model for Energy Aware TDMA-based MAC Protocol for Wireless Sensor Network System

Computational Model for Energy Aware TDMA-based MAC Protocol for Wireless Sensor Network System 6th WSEAS International Conference on CIRCUITS, SYSTEMS, ELECTRONICS,CONTROL & SIGNAL PROCESSING, Cairo, Egypt, Dec 29-31, 2007 489 Computational Model for Energy Aware TDMA-based MAC Protocol for Wireless

More information

Research Article MFT-MAC: A Duty-Cycle MAC Protocol Using Multiframe Transmission for Wireless Sensor Networks

Research Article MFT-MAC: A Duty-Cycle MAC Protocol Using Multiframe Transmission for Wireless Sensor Networks Distributed Sensor Networks Volume 2013, Article ID 858765, 6 pages http://dx.doi.org/10.1155/2013/858765 Research Article MFT-MAC: A Duty-Cycle MAC Protocol Using Multiframe Transmission for Wireless

More information

MAC protocols. Lecturer: Dmitri A. Moltchanov

MAC protocols. Lecturer: Dmitri A. Moltchanov MAC protocols Lecturer: Dmitri A. Moltchanov E-mail: moltchan@cs.tut.fi http://www.cs.tut.fi/kurssit/tlt-2616/ OUTLINE: Problems for MAC to deal with; Design goals; Classification of MAC protocols Contention-based

More information

Multiple Access. Data Communications and Networking

Multiple Access. Data Communications and Networking Multiple Access In the previous part we discussed data link control, a mechanism which provides a link with reliable communication. In the protocols we described, we assumed that there is an available

More information

Sensor Network Protocols

Sensor Network Protocols EE360: Lecture 15 Outline Sensor Network Protocols Announcements 2nd paper summary due March 7 Reschedule Wed lecture: 11-12:15? 12-1:15? 5-6:15? Project poster session March 15 5:30pm? Next HW posted

More information