Investigating MAC-layer Schemes to Promote Doze Mode in based WLANs
|
|
- Gabriella Boyd
- 6 years ago
- Views:
Transcription
1 Investigating MAC-layer Schemes to Promote Doze Mode in based WLANs V. Baiamonte and C.-F. Chiasserini CERCOM - Dipartimento di Elettronica Politecnico di Torino Torino, Italy Abstract This paper addresses the energy saving issue in based WLANs. Previous work has pointed out that the power management function in the IEEE standard presents some inefficiencies, thus other solutions to energy saving are needed. We focus on an infrastructure WLAN and explore the possibility to increase the time period that a wireless station spends in the low-power operational state, the so-called doze state. We present an energy-saving, MAC-layer scheme which is derived from the DCF. The proposed mechanism enables a station to enter the doze state during channel contention by exploiting the virtual carrier sense mechanism and the backoff function. We compare the performance obtained through the proposed scheme with the results attained through both the standard DCF and a simple active/doze state switching mechanism. I. INTRODUCTION Today Wireless Local Area Networks (WLANs) based on the IEEE standard [1] are widely deployed, since they both support user mobility and provide high data rates. Nevertheless, current technology still has some limitations, such as the lack of quality of service support, the unfairness of the Medium Access Control (MAC) function and the high energy consumption experienced by battery-powered wireless stations (WSTAs) [2], [3]. In this work we focus on the energy efficiency issue, which is critical to the performance of the WLAN technology. Indeed, typical values for the power consumption of a WLAN card are as follows: =1.65 W in transmit mode, =1.4 W in receive mode, =1.15 W in idle mode (i.e., when the channel is sensed without actively receiving), and =0.045 W in doze mode (i.e., when the RF circuitry is turned off) [3], [4]. These values of power consumption suggest that, in order to save energy, we need to reduce the time spent by a This work was partially funded by MIUR (Italian Ministry of Research) through the PRIMO project. WSTA in idle mode and increase as much as possible its time in doze mode. The IEEE standard specifies a Power Management (PM) function, which allows a WSTA to switch to the doze mode when the interface is idle [1]. Several studies however show that the PM scheme presents some inefficiencies and propose solutions to overcome the PM limitations. In particular, in [3] the authors observe the PM inefficiency due to the fixed beacon interval duration and propose a scheme controlling the transition to the doze state in the middle of a beacon interval. Solutions to energy saving in based WLANs have also been proposed in [5], [6]. In this work, we devise a novel scheme at the MAC layer, called the drowsy scheme, which allows WSTAs to enter the doze state while participating in the network activity. By applying the drowsy technique, a WSTA greatly reduces its channel-sensing activity thus saving energy. However there exists a trade-off between energy saving and traffic delivery delay. We investigate this trade-off and compare the performance of our scheme with the results obtained through the standard Distributed Coordination Function (DCF) as well as through a simple active/doze switching mechanism. The study is performed by using the network simulator ns [7]. We highlight that the drowsy technique can be used either as an alternative to the PM function or jointly with the standard PM function. The remainder of the paper is organized as follows. In Section II we describe the network scenario under study. Section III first describes the proposed energy-efficient technique, then it presents a simple active/doze state switching mechanism that we consider for comparison to our scheme. In Section IV we show some performance results comparing the drowsy technique to the standard DCF function and to the simple active/doze switching mechanism. Section V concludes the paper and points at some aspects that will be the subject of future research.
2 II. REFERENCE SCENARIO We consider an b-based WLAN, which includes an Access Point (AP) and several stationary WSTAs using a bit rate over the wireless channel of 11 Mbit/s. When no modifications are introduced in the access scheme, the WSTAs employ the IEEE DCF [1]. The DCF operates as follows. It exploits both a physical and a virtual channel sensing; virtual sensing is implemented by including in all transmitted frames an indication of their duration so that the non-destination WSTAs overhearing a transmission can set their NAV accordingly. Once a WSTA has set its NAV, it is in idle state [2]. When a WSTA has to transmit a frame, the physical and virtual carrier sense mechanisms are checked. If within an interval of DIFS (or EIFS if the previous frame was received in error) either the physical or virtual carrier sense mechanisms detect the channel as busy, the WSTA selects a backoff interval, that is decremented only during idle channel periods. Again, a WSTA can be considered as in idle state during the backoff time. With regard to the wireless channel behavior, we consider an independent error model for each communicating pair of nodes. The error model is represented by a three-state discrete-time Markov chain. The Markov chain time slot is equal to the b time slot duration. Errors over the channel occur in the states long bad (LB) and short bad (SB), while the good (G) state is error-free. Thus, a frame transmission is successful only if the error model is in state G for all slots it takes the frame to be transmitted, while it fails otherwise. The difference between the long bad and short bad states is the time correlation of errors: corresponds to long bursts of errors, SB to short ones. The probability that the Markov chain moves to the state given that it leaves the state, i.e., the probability that an error burst is long, is set to We assume that the average time duration of a burst of bad slots experienced when the states and are entered, are respectively equal to 1.3 s and 0.04 s. The average number of consecutive error-free slots is set to 1 s. III. ENERGY-EFFICIENT TECHNIQUES In this section, we first introduce the proposed energyefficient technique, called the drowsy scheme; then we briefly describe a simple active/doze state switching scheme that will be used as term of comparison in the performance study in Section IV. A. The Scheme Our aim is to reduce the time spent by a WSTA in idle state and enable the WSTA to enter the doze state Other WSTAs Backoff (( """"" NAV &&&& ''' $$$$$$$ %%%%%% (( ))!!!!!!!""""" ##### WSTA &&&& ''' $$$$$$$ %%%%%% ))!!!!!!!##### NAV NAV DIFS WSTA Fig. 1. NAV Backoff Data Sensing and backoff decreasing (idle state) Idle state Dozing Backoff freezing (idle state) Modified backoff counter management in the drowsy scheme instead. To widen the time of inactivity of a WSTA so as to be able to move into the doze state and save energy, we act on two different aspects: (i) we exploit the virtual carrier sense mechanism, and (ii) we change the backoff management technique. First, consider that the MAC layer of a WSTA receives data to transmit from the upper layers and starts listening to the channel while a frame transmission is taking place. Assume that the WSTA can read the frame duration field in the frame header and set its NAV. According to the drowsy scheme, the WSTA also computes a backoff interval and sets its backoff counter to this value. While in the standard the backoff is decremented only during idle channel periods, the drowsy WSTA continuously decreases its backoff counter with time. This implies that the WSTA does not need to sense the channel while being in backoff but it can be in doze state. When the backoff counter reaches zero, the drowsy WSTA behaves following the DCF scheme as specified in the IEEE standard. The drowsy WSTA mechanism is presented and compared with the DCF scheme in Figure 1. Note that, if the WSTA cannot read the frame duration field in the frame header and, hence, cannot set its NAV, it waits a time interval equal to EIFS as in the DCF. Then, after the WSTA computes its backoff time, it applies the drowsy backoff management technique described above. We remark that, since the drowsy WSTA decrements the backoff counter continuously, the Contention Window (CW) should be enlarged in order to extend the backoff interval. B. A Active/Doze Switching Mechanism We consider a simple and ideal mechanism which controls the WSTA transition from the active state (where the WSTA can transmit/receive) to the doze state
3 Fig. 2. MAX_WAITING_TIME Doze Idle DOZE_TIME TX/RX Start My_RX/TX TX/RX End TX/RX State machine for the simple active/doze switching scheme TABLE I PARAMETER SETTING CW CW RTS Threshold 400 bytes Slot time SIFS time DIFS time EIFS Short Retry Limit 7 Long Retry Limit 4 Preamble Length 144 bits PCLP length 48 bits ACK Frame Length 112 bits and vice-versa. When this scheme is implemented, a WSTA operates according to the state machine shown in Figure 2. Consider that the WSTA is in idle state. If the WSTA remains idle for a time period equal to MAX WAITING TIME, then it moves into the doze state. The maximum time spent by the WSTA in doze state is equal to DOZE TIME, afterwards the WSTA switches back to the idle state. However, if the WSTA needs to wake up to receive or transmit a frame while being in doze state, it moves into the TX/RX state. As a frame transmission/reception ends, the WSTA moves into the idle state. Clearly, this mechanism assumes an ideal behavior of WSTAs since WSTAs should be able to switch from the doze state to the TX/RX state as they are about to receive a frame. In actual implementations, this is unfeasible without using a low-power circuit, which allows us to wake up WSTAs when needed. IV. NUMERICAL RESULTS We derive the system performance via simulation, by extending the network simulator ns [7]. We assume that each WSTA has one uplink traffic connection with the AP. Indeed, considering uplink traffic only eases the implementation of the active/doze switching mechanism described in Section III-B, without affecting the performance of the drowsy scheme. The traffic offered to the network by each WSTA is generated by UDP flows exhibiting an on-off behavior. During off periods no traffic is generated; the average duration of the off period, denoted by off, is taken as a constant parameter and is set to 6 s. On the contrary, during on periods, the WSTA generates traffic at a constant rate of 256 kbit/s; the average duration of the on period is a configurable parameter that we vary in our simulations. Thus, we can act on the system load by tuning the value of the on period as well as the number of WSTAs in the network. The wireless channel is modeled as described in Section II, while the parameter setting that we adopt is presented in Table I. As for the power consumption in the WSTA operational states, we consider the following values: =1.65 W, =1.4 W, =1.15 W, and =0.045 W. The plots that are shown in the following present the average energy consumption per successful packet (i.e., successfully delivered packet to the AP), and the average total packet delay that is computed as the sum of queueing delay and service delay at the MAC layer. The results obtained through the drowsy scheme are compared to the performance of the DCF (tagged standard ) and of the simple active/doze switching mechanism (tagged simple ). In the case of the simple active/doze switching mechanism, we set MAX WAITING TIME and DOZE TIME to 2 and 5 s, respectively. In the case of the drowsy scheme, we present results for two different CW settings: CW =31 and CW =1023 (tagged drowsy ), and CW =63 and CW =2047 (tagged drowsy large CW ). Figure 3 presents the energy consumption per successful packet as a function of the ratio on off, i.e., of the total offered traffic load, when the number of WSTAs is equal to 10. Note that under the assumptions introduced above on off =0.25 corresponds to a total traffic generation rate equal to 512 kbit/s, while on off =2.5 corresponds to a total generation rate of 1.82 Mbit/s. Figure 3 shows that the drowsy scheme outperforms both the standard and the simple mechanism, regardless of the CW size and of the value of traffic load. As for the simple scheme, one would expect a significant improvement in energy consumption with respect to the standard case. Instead, the difference between the simple and the standard scheme behavior is negligible. To let such a difference become evident, smaller values of traffic load should be considered. As a last remark, we observe that the energy consumption per successful
4 Energy per successful packet (J) large CW Energy per successful packet (J) large CW Ton/Toff Fig. 3. Average energy consumption per successful packet versus the ratio on off, when off s and the number of WSTAs in the system is equal to 10. The performance of the drowsy scheme with different CW size, of the standard function, and of the simple active/doze switching mechanism are compared Wireless Stations Fig. 5. Average energy consumption per successful packet versus the number of wireless stations, for on s and off s. The performance of the drowsy scheme with different CW size, of the standard function, and of the simple active/doze switching mechanism are compared large CW 10 1 large CW Average total delay (s) Average total delay (s) Ton/Toff Fig. 4. Average total packet delay as a function of the ratio on off, when off s and the number of WSTAs in the system is equal to 10. The performance of the drowsy scheme with different CW size, of the standard function, and of the simple active/doze switching mechanism are compared Wireless Stations Fig. 6. Average total packet delay as a function of the number of wireless stations, for on s and off s. The performance of the drowsy scheme with different CW size, of the standard function, and of the simple active/doze switching mechanism are compared packet decreases as the ratio on off increases. This is because as the on period increases, the time spent in idle state by WSTAs becomes shorter. This suggests that the contribution of the idle state to energy consumption is still quite significant in all of the considered schemes, and that there is still some margin of improvement. Figure 4 shows the average total packet delay as a function of the ratio on off, in the case of 10 WSTAs. As expected, our scheme implies larger packet delay, especially in the case of large values of on off. Looking at Figures 3 and 4, we can see the energy/delay trade-off that can be achieved through the drowsy mechanism. Figures 5 and 6 present the average energy consumption per successful packet and the average total packet delay, respectively, as the number of WSTAs in the system varies. Results are derived by fixing on at 3 s. Figure 5 shows that the drowsy mechanism with a larger CW always gives better performances than both the standard and the simple technique. Whereas, the performance of the drowsy scheme with a smaller CW degrades as the number of WSTAs exceeds 13 because of the high number of collisions. As shown in Figure 6,
5 the average packet delay grows with the increase in the number of contending WSTAs, and, as expected, the drowsy mechanism behaves worse than the standard and the simple scheme. Clearly, such a degradation becomes more remarkable as the number of WSTAs grows. These results suggest that the drowsy scheme gives excellent performance in terms of energy consumption, even under high traffic load conditions. On the contrary, the difference between the performance of the simple mechanism and of the standard scheme is negligible unless a very low traffic load is considered. However, in the drowsy scheme the remarkable energy saving is obtained at the cost of a larger packet delay. Furthermore, in the case of the drowsy scheme we need to enlarge the CW as the number of WSTAs increases in order to keep the collision probability small. [6] L. Bononi, M. Conti, L. Donatiello, A Distributed Mechanism for Power Saving in IEEE Wireless LANs, ACM Mobile Networks and Applications (MONET), vol. 6, no. 3, pp , [7] UCB/LBNL/VINT, Network Simulator ns version 2.26, URL: V. CONCLUSIONS AND FUTURE WORK This paper addressed the issue of energy efficiency in WLANs. We proposed a novel energy-saving, MAClayer scheme which is derived from the DCF specified in the IEEE standard. The proposed scheme enables a wireless station to enter the low-power operational state, the so-called doze state, while the NAV is set as well as during the backoff time interval. We investigated through simulation the trade-off existing between energy saving and traffic delivery delay, and compared the performance of the proposed scheme with those obtained through both the standard DCF and a simple active/doze state switching mechanism. Further improvements of the proposed enery-saving scheme are currently under study. Using the proposed technique does not preclude using the power management function in the IEEE standard. Rather, the two schemes could be jointly used. In our future work, we will study the system performance when the power management function is implemented. REFERENCES [1] IEEE WG, Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications, [2] L. M. Feeney, M. Nilsson, Investigating the energy consumption of a wireless network interface in an ad hoc networking environment, INFOCOM 2001, Anchorage, Alaska, [3] E.-S. Jung, N. H. Vaidya, An energy efficient MAC protocol for wireless LANs, INFOCOM 2002, New York, NY, [4] A. Kamerman, L. Monteban, WaveLAN-II: A High Performance Wireless LAN for the unlicensed band, Bell Labs Technical Journal, vol. 2, no. 3, [5] Y.-C. Tseng, C.-S. Hsu, T.-Y. Hsieh, Power-Saving Protocols for IEEE Based Multi-Hop Ad Hoc Networks, Infocom 2002, New York, June 2002.
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 informationMohammad Hossein Manshaei 1393
Mohammad Hossein Manshaei manshaei@gmail.com 1393 1 An Analytical Approach: Bianchi Model 2 Real Experimentations HoE on IEEE 802.11b Analytical Models Bianchi s Model Simulations ns-2 3 N links with the
More informationCollision Probability in Saturated IEEE Networks
in Saturated IEEE 80.11 Networks Hai L. Vu Centre for Advanced Internet Architectures (CAIA) ICT Faculty, Swinburne University of Technology Hawthorn, VIC 31, Australia h.vu@ieee.org Taka Sakurai ARC Special
More informationAn 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 informationAnalysis 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 informationImpact 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 informationEBA: An Enhancement of IEEE DCF via Distributed Reservation
EBA: An Enhancement of IEEE 802.11 DCF via Distributed Reservation Jaehyuk Choi, Joon Yoo, Sunghyun Choi, Member, IEEE, and Chongkwon Kim, Member, IEEE Abstract The IEEE 802.11 standard for Wireless Local
More informationPerformance Analysis of WLANs Under Sporadic Traffic
Performance Analysis of 802.11 WLANs Under Sporadic Traffic M. Garetto and C.-F. Chiasserini Dipartimento di Elettronica, Politecnico di Torino, Italy Abstract. We analyze the performance of 802.11 WLANs
More informationMohamed 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 informationEnhanced 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 informationLecture 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 informationNotes on the Inefficiency of e HCCA
Notes on the Inefficiency of 802.e HCCA C. Casetti, C.-F. Chiasserini, M. Fiore and M. Garetto Dipartimento di Elettronica, Politecnico di Torino - Italy E-mail: {casetti,chiasserini,fiore,garetto}@polito.it
More informationCSE 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 informationA Backoff Algorithm for Improving Saturation Throughput in IEEE DCF
A Backoff Algorithm for Improving Saturation Throughput in IEEE 80.11 DCF Kiyoshi Takahashi and Toshinori Tsuboi School of Computer Science, Tokyo University of Technology, 1404-1 Katakura, Hachioji, Tokyo,
More informationWireless Local Area Networks (WLANs) Part I
Wireless Local Area Networks (WLANs) Part I Raj Jain Professor of CSE Washington University in Saint Louis Saint Louis, MO 63130 Jain@cse.wustl.edu These slides are available on-line at: http://www.cse.wustl.edu/~jain/cse574-08/
More informationPerformance Analysis of Energy-Efficient MAC Protocols using Bidirectional Transmissions and Sleep Periods in IEEE 802.
Performance Analysis of Energy-Efficient MAC otocols using Bidirectional Transmissions and Sleep Periods in IEEE 82.-based WLANs* Raul Palacios a, El Moatez Billah Larbaa a, Jesus Alonso-Zarate b and Fabrizio
More informationAn Energy Consumption Analytic Model for A Wireless Sensor MAC Protocol
An Energy Consumption Analytic Model for A Wireless Sensor MAC Protocol Hung-Wei Tseng, Shih-Hsien Yang, Po-Yu Chuang,Eric Hsiao-Kuang Wu, and Gen-Huey Chen Dept. of Computer Science and Information Engineering,
More informationLesson 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 informationoriginal standard a transmission at 5 GHz bit rate 54 Mbit/s b support for 5.5 and 11 Mbit/s e QoS
IEEE 802.11 The standard defines a wireless physical interface and the MAC layer while LLC layer is defined in 802.2. The standardization process, started in 1990, is still going on; some versions are:
More informationIEEE 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 informationMedium Access Control. MAC protocols: design goals, challenges, contention-based and contention-free protocols
Medium Access Control MAC protocols: design goals, challenges, contention-based and contention-free protocols 1 Why do we need MAC protocols? Wireless medium is shared Many nodes may need to access the
More informationHigh Performance Distributed Coordination Function for Wireless LANs
High Performance Distributed Coordination Function for Wireless LANs Haithem Al-Mefleh and J. Morris Chang Dept. of Electrical and Computer Engineering Iowa State University, Ames, IA 511, USA {almehai,morris}@iastate.edu
More informationTwo-phase Collision Avoidance to Improve Scalability in Wireless LANs
Two-phase Collision Avoidance to Improve Scalability in Wireless LANs Seongil Han, Yongsub Nam, Yongho Seok, Taekyoung Kwon and Yanghee Choi School of Computer Science and Engineering Seoul National University,
More informationCSC344 Wireless and Mobile Computing. Department of Computer Science COMSATS Institute of Information Technology
CSC344 Wireless and Mobile Computing Department of Computer Science COMSATS Institute of Information Technology Wireless Local Area Networks (WLANs) Part I Almost all wireless LANs now are IEEE 802.11
More informationMAC. Fall Data Communications II 1
802.11 MAC Fall 2005 91.564 Data Communications II 1 RF Quality (ACK) Fall 2005 91.564 Data Communications II 2 Hidden Terminal (RTS/CTS) Fall 2005 91.564 Data Communications II 3 MAC Coordination Functions
More informationMulti-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 informationA Multi-channel MAC Protocol for Ad Hoc Wireless Networks
A Multi-channel MAC Protocol for Ad Hoc Wireless Networks Jungmin So Dept. of Computer Science, and Coordinated Science Laboratory University of Illinois at Urbana-Champaign Email: jso1@uiuc.edu Nitin
More informationDepartment 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 informationWireless Networking & Mobile Computing
Wireless Networking & Mobile Computing CS 752/852 - Spring 2012 Lec #4: Medium Access Control - II Tamer Nadeem Dept. of Computer Science IEEE 802.11 Standards Page 2 Spring 2012 CS 752/852 - Wireless
More informationComparison of pre-backoff and post-backoff procedures for IEEE distributed coordination function
Comparison of pre-backoff and post-backoff procedures for IEEE 802.11 distributed coordination function Ping Zhong, Xuemin Hong, Xiaofang Wu, Jianghong Shi a), and Huihuang Chen School of Information Science
More informationEnhancements 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 informationAn Accurate Model for Energy Efficiency in IEEE WLANs
An Accurate Model for Energy Efficiency in IEEE 802.11 WLANs Eleni-Constantina Davri, Emmanouil Kafetzakis, Kimon Kontovasilis, Charalabos Skianis National Centre for Scientific Research Demokritos, Athens,
More informationA Hybrid Distributed Coordination Function for Scalability and Inter-operability in Large-scale WLANs
A Hybrid Distributed Coordination Function for Scalability and Inter-operability in Large-scale WLANs Nakjung Choi, Seongil Han, Yongho Seok, Yanghee Choi and Taekyoung Kwon School of Computer Science
More informationEnhancing the DCF mechanism in noisy environment
Enhancing the DCF mechanism in noisy environment 1 LICP EA 2175 Université de Cergy-Pontoise 3 Av Adolph Chauvin 9532 Cergy-Pontoise France Email: {adlen.ksentini, mohamed.naimi}@dept-info.u-cergy.fr Adlen
More informationEnergy Efficiency of an Enhanced DCF Access Method using Bidirectional Communications for Infrastructure-based IEEE WLANs
3 IEEE 8th International Workshop on Computer Aided Modeling and Design of Communication Links and Networks (CAMAD) Energy Efficiency of an Enhanced Access Method using Bidirectional Communications for
More informationWireless Networked Systems
Wireless Networked Systems CS 795/895 - Spring 2013 Lec #6: Medium Access Control QoS and Service Differentiation, and Power Management Tamer Nadeem Dept. of Computer Science Quality of Service (802.11e)
More informationExpanding the use of CTS-to-Self mechanism to improving broadcasting on IEEE networks
Expanding the use of CTS-to-Self mechanism to improving broadcasting on IEEE 802.11 networks Christos Chousidis, Rajagopal Nilavalan School of Engineering and Design Brunel University London, UK {christos.chousidis,
More informationAnalytical Modeling of TCP Clients in Wi-Fi Hot Spot Networks
Analytical Modeling of TCP Clients in Wi-Fi Hot Spot Networks Raffaele Bruno, Marco Conti, and Enrico Gregori Italian National Research Council (CNR) IIT Institute Via G. Moruzzi, 1-56100 Pisa, Italy {firstname.lastname}@iit.cnr.it
More informationCHAPTER 4 CALL ADMISSION CONTROL BASED ON BANDWIDTH ALLOCATION (CACBA)
92 CHAPTER 4 CALL ADMISSION CONTROL BASED ON BANDWIDTH ALLOCATION (CACBA) 4.1 INTRODUCTION In our previous work, we have presented a cross-layer based routing protocol with a power saving technique (CBRP-PS)
More informationThroughput Evaluation and Enhancement of TCP Clients in Wi-Fi Hot Spots
Throughput Evaluation and Enhancement of TCP Clients in Wi-Fi Hot Spots Raffaele Bruno 1, Marco Conti 1, and Enrico Gregori 1 Italian National Research Council (CNR) - IIT Institute, Via G. Moruzzi 1,
More informationH-MMAC: A Hybrid Multi-channel MAC Protocol for Wireless Ad hoc Networks
H-: A Hybrid Multi-channel MAC Protocol for Wireless Ad hoc Networks Duc Ngoc Minh Dang Department of Computer Engineering Kyung Hee University, Korea Email: dnmduc@khu.ac.kr Choong Seon Hong Department
More informationWireless LANs. ITS 413 Internet Technologies and Applications
Wireless LANs ITS 413 Internet Technologies and Applications Aim: Aim and Contents Understand how IEEE 802.11 wireless LANs work Understand what influences the performance of wireless LANs Contents: IEEE
More informationMAC 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 informationAn energy-efficient MAC protocol for infrastructure WLAN based on modified PCF/ DCF access schemes using a bidirectional data packet exchange
An energy-efficient MAC protocol for infrastructure WLAN based on modified PCF/ DCF access schemes using a bidirectional data packet exchange Raúl Palacios, Fabrizio Granelli University of Trento Trento,
More informationFairness in the IEEE network. Shun Y. Cheung
Fairness in the IEEE 802.11 network Shun Y. Cheung Simple FIFO queueing High data rate flow Output queue (infinite size) Low data rate flow Packets from low data rate flow experience excessive queueing
More informationEVALUATION OF EDCF MECHANISM FOR QoS IN IEEE WIRELESS NETWORKS
MERL A MITSUBISHI ELECTRIC RESEARCH LABORATORY http://www.merl.com EVALUATION OF EDCF MECHANISM FOR QoS IN IEEE802.11 WIRELESS NETWORKS Daqing Gu and Jinyun Zhang TR-2003-51 May 2003 Abstract In this paper,
More informationP 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 informationAN 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 informationAGOOD medium access control (MAC) protocol for wireless
IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS, VOL. 3, NO. 3, MAY 2004 793 Design of MAC Protocols With Fast Collision Resolution for Wireless Local Area Networks Younggoo Kwon, Yuguang Fang, Senior Member,
More informationImproving the Multiple Access Method of CSMA/CA Home Networks
Improving the Multiple Access Method of CSMA/CA Home Networks Miguel Elias M. Campista, Luís Henrique M. K. Costa, and Otto Carlos M. B. Duarte Universidade Federal do Rio de Janeiro - PEE-COPPE/DEL-POLI
More informationWLAN Performance Aspects
Mobile Networks Module C- Part 1 WLAN Performance Aspects Mohammad Hossein Manshaei Jean-Pierre Hubaux http://mobnet.epfl.ch 1 Performance Evaluation of IEEE 802.11(DCF) Real Experimentations HoE on IEEE
More informationReliable Multicast Scheme Based on Busy Signal in Wireless LANs
Journal of Modern Science and Technology Vol.2 No.1 March 2014. Pp.18-25 Reliable Multicast Scheme Based on Busy Signal in Wireless LANs Sunmyeng For unicast transmissions, the IEEE 802.11 WLAN MAC (Medium
More informationData and Computer Communications. Chapter 13 Wireless LANs
Data and Computer Communications Chapter 13 Wireless LANs Wireless LAN Topology Infrastructure LAN Connect to stations on wired LAN and in other cells May do automatic handoff Ad hoc LAN No hub Peer-to-peer
More informationPerformance Anomaly of b
Performance Anomaly of 8.11b Martin Heusse, Franck Rousseau, Gilles Berger-Sabbatel, Andrzej Duda LSR-IMAG Laboratory Grenoble, France email: {heusse, rousseau, gberger, duda}@imag.fr Abstract We analyze
More informationData 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 informationGuide to Wireless Communications, Third Edition. Objectives
Guide to Wireless Communications, Third Edition Chapter 7 Low-Speed Wireless Local Area Networks Objectives Describe how WLANs are used List the components and modes of a WLAN Describe how an RF WLAN works
More informationBLAM: An Energy-Aware MAC Layer Enhancement for Wireless Adhoc Networks
: An Energy-Aware MAC Layer Enhancement for Wireless Adhoc Networks Sameh Gobriel, Rami Melhem and Daniel Mossé Computer Science Department, University of Pittsburgh {sameh, melhem, mosse}@cs.pitt.edu
More informationSENSOR-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 informationMulti-rate Opportunistic Spectrum Access in Multi-hop Ad Hoc Networks
22nd IEEE Personal Indoor Mobile Radio Communications Multi-rate Opportunistic Spectrum Access in Multi-hop Ad Hoc Networks Ari Raptino H Graduate school of Shizuoka University Hamamatsu, Japan Email:
More informationMulti-Rated Packet Transmission Scheme for IEEE WLAN Networks
Multi-Rated Packet Transmission Scheme for IEEE 802.11 WLAN Networks Namgi Kim Telecommunication R&D Center, Samsung Electronics, 416, Maetan-3, Youngtong, Suwon, Kyounggi, 442-600, Korea namgi.kim@samsung.com
More informationDelivering Voice over IEEE WLAN Networks
Delivering Voice over IEEE 802.11 WLAN Networks Al Petrick, Jim Zyren, Juan Figueroa Harris Semiconductor Palm Bay Florida Abstract The IEEE 802.11 wireless LAN standard was developed primarily for packet
More informationAn Energy-Efficient MAC using Dynamic Phase Shift for Wireless Sensor Networks
An Energy-Efficient MAC using Dynamic Phase Shift for Wireless Sensor Networks Yoh-han Lee Department of Electrical Engineering Korea Advanced Institute of Science & Technology Daejeon, KOREA yohhanlee@kaist.ac.kr
More informationRARA: Rate Adaptation Using Rate-adaptive Acknowledgment for IEEE WLANs
: Rate Adaptation Using Rate-adaptive Acknowledgment for IEEE 8. WLANs Hakyung Jung,KideokCho, Yongho Seok, Taekyoung Kwon and Yanghee Choi School of Computer Science and Engineering, Seoul National University,
More informationIEEE Ad Hoc Networks: Performance Measurements
IEEE 8.11 Ad Hoc Networks: Performance Measurements Giuseppe Anastasi Dept. of Information Engineering University of Pisa Via Diotisalvi - 561 Pisa, Italy Email: g.anastasi@iet.unipi.it Eleonora Borgia,
More informationSolutions to Performance Problems in VoIP Over a Wireless LAN
Solutions to Performance Problems in VoIP Over a 802.11 Wireless LAN Wei Wang, Soung C. Liew, and VOK Li, Solutions to Performance Problems in VoIP over a 802.11 Wireless LAN, IEEE Transactions On Vehicular
More informationWireless 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 informationRemarks On Per-flow Differentiation In IEEE
Remarks On Per-flow Differentiation In IEEE 82.11 Imad Aad and Claude Castelluccia PLANETE project, INRIA Rhône-Alpes ZIRST - 655, Avenue de l Europe - Montbonnot. 38334 Saint Ismier Cedex - France [imad.aad,
More informationActual4Test. Actual4test - actual test exam dumps-pass for IT exams
Actual4Test http://www.actual4test.com Actual4test - actual test exam dumps-pass for IT exams Exam : PW0-205 Title : Certified wireless analusis professional(cwap) Vendors : CWNP Version : DEMO Get Latest
More informationMobile & Wireless Networking. Lecture 7: Wireless LAN
192620010 Mobile & Wireless Networking Lecture 7: Wireless LAN [Schiller, Section 7.3] [Reader, Part 6] [Optional: "IEEE 802.11n Development: History, Process, and Technology", Perahia, IEEE Communications
More informationERBAR: an Enhanced Receiver-Based Auto-Rate MAC Protocol for Wireless Ad Hoc Networks
ERBAR: an Enhanced Receiver-Based Auto-Rate MAC Protocol for Wireless Ad Hoc Networks Zhifei Li, Anil K. Gupta, and Sukumar Nandi School of Computer Engineering, Nanyang Technological University, Singapore-639798
More informationSupporting VBR VoIP Traffic in IEEE WLAN in PCF Mode
Supporting VBR VoIP Traffic in IEEE 802.11 WLAN in PCF Mode Dongyan Chen*, Sachin Garg**, Martin Kappes** and Kishor S. Trivedi* * Center for Advanced Computing and Communications, ECE Department Duke
More informationWireless 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 informationPerformance evaluation of IEEE e
IJCSNS International Journal of Computer Science and Network Security, VOL.11 No.7, July 2011 159 Performance evaluation of IEEE 802.11e Sandeep kaur 1, Dr.jyotsna sengupta 2 Department of Computer Science,
More information2 Related Work. 1 Introduction. 3 Background
Modeling the Performance of A Wireless Node in Multihop Ad-Hoc Networks Ping Ding, JoAnne Holliday, Aslihan Celik {pding, jholliday, acelik}@scu.edu Santa Clara University Abstract: In this paper, we model
More informationLecture 25: CSE 123: Computer Networks Alex C. Snoeren. HW4 due NOW
Lecture 25: 802.11 CSE 123: Computer Networks Alex C. Snoeren HW4 due NOW Lecture 25 Overview 802.11 Wireless PHY layer overview Hidden Terminals Basic wireless challenge RTS/CTS Virtual carrier sense
More informationA Medium Access Control Protocol with Retransmission using NACK and Directional Antennas for Broadcasting in Wireless Ad-Hoc Networks
A Medium Access Control Protocol with Retransmission using NACK and Directional Antennas for Broadcasting in Wireless Ad-Hoc Networks Yoriko Utsunomiya, Michito Takahashi, Masaki Bandai, and Iwao Sasase
More informationExperimental Framework and Simulator for the MAC of Power-Line Communications
Experimental Framework and Simulator for the MAC of Power-Line Communications Technical Report Christina Vlachou EPFL, Switzerland christinavlachou@epflch Julien Herzen EPFL, Switzerland julienherzen@epflch
More informationAdaptive EDCF: Enhanced Service Differentiation for IEEE Wireless Ad-Hoc Networks
Adaptive : Enhanced Service Differentiation for IEEE 82.11 Wireless Ad-Hoc Networks Lamia Romdhani, Qiang Ni, and Thierry Turletti INRIA Sophia Antipolis, 24 Route des Lucioles, BP-93, 692 Sophia Antipolis,
More informationLecture 24: CSE 123: Computer Networks Stefan Savage. HW4 due NOW
Lecture 24: 802.11 CSE 123: Computer Networks Stefan Savage HW4 due NOW About the final Similar in style to midterm Some combination of easy questions, short answer and more in-depth questions Sample final
More information4.3 IEEE Physical Layer IEEE IEEE b IEEE a IEEE g IEEE n IEEE 802.
4.3 IEEE 802.11 Physical Layer 4.3.1 IEEE 802.11 4.3.2 IEEE 802.11b 4.3.3 IEEE 802.11a 4.3.4 IEEE 802.11g 4.3.5 IEEE 802.11n 4.3.6 IEEE 802.11ac,ad Andreas Könsgen Summer Term 2012 4.3.3 IEEE 802.11a Data
More informationWireless 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 informationAccurate and Energy-efficient Congestion Level Measurement in Ad Hoc Networks
Accurate and Energy-efficient Congestion Level Measurement in Ad Hoc Networks Jaewon Kang Computer Science Rutgers University jwkang@cs.rutgers.edu Yanyong Zhang Electrical & Computer Engineering Rutgers
More informationPerformance Evaluation of IEEE e
Performance Evaluation of IEEE 802.11e 1 Sandeep Kaur, 2 Dr. Jyotsna Sengupta 1,2 Dept. of Computer Science, Punjabi University, Patiala, India Abstract Providing QoS requirements like good throughput
More informationLocal 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 informationIntroduction to IEEE
Introduction to IEEE 802.11 Characteristics of wireless LANs Advantages very flexible within the reception area Ad hoc networks without previous planning possible (almost) no wiring difficulties more robust
More informationEnergy Efficiency in IEEE standard WLAN through MWTPP
IOSR Journal of Computer Engineering (IOSR-JCE) e-issn: 2278-0661, p- ISSN: 2278-8727Volume 16, Issue 1, Ver. I (Jan. 2014), PP 42-46 Efficiency in IEEE 802.11 standard WLAN through MWTPP Anupam Das, Prof.
More informationAnalytical Model for an IEEE WLAN using DCF with Two Types of VoIP Calls
Analytical Model for an IEEE 802.11 WLAN using DCF with Two Types of VoIP Calls Sri Harsha Anurag Kumar Vinod Sharma Department of Electrical Communication Engineering Indian Institute of Science Bangalore
More informationAdaptive Fair Channel Allocation for QoS Enhancement in IEEE Wireless LANs
Adaptive Fair Channel Allocation for QoS Enhancement in IEEE 82.11 Wireless LANs Mohammad Malli, Qiang Ni, Thierry Turletti, Chadi Barakat Projet Planète, INRIA-Sophia Antipolis, France E-mail: mmalli,
More informationMaximum Traffic Scheduling and Capacity Analysis for IEEE High Data Rate MAC Protocol
Maximum Traffic Scheduling and Capacity Analysis for IEEE 80..3 High Data Rate MAC Protocol Yi-Hsien Tseng, Eric Hsiao-kuang Wu and Gen-Huey Chen Department of Computer Science and Information Engineering,
More informationCollision 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 informationMOST wireless stations, such as laptops and palmtops,
IEEE/ACM TRANSACTIONS ON NETWORKING, VOL. 15, NO. 5, OCTOBER 2007 1007 Interference Analysis and Transmit Power Control in IEEE 802.11a/h Wireless LANs Daji Qiao, Member, IEEE, Sunghyun Choi, Senior Member,
More informationIEEE C802.16h-07/017. IEEE Broadband Wireless Access Working Group <
Project Title Date Submitted IEEE 82.16 Broadband Wireless Access Working Group Simulation of IEEE 82.16h and IEEE Coexistence (Preliminary Report) 7-1-12 Source(s) John Sydor, Amir
More informationJune 20th, École Polytechnique, Paris, France. A mean-field model for WLANs. Florent Cadoux. IEEE single-cell WLANs
Initial Markov under Bianchi s École Polytechnique, Paris, France June 20th, 2005 Outline Initial Markov under Bianchi s 1 2 Initial Markov under Bianchi s 3 Outline Initial Markov under Bianchi s 1 2
More informationThe IEEE Distributed Coordination Function in Small-Scale Ad-Hoc Wireless LANs
International Journal of Wireless Information Networks, Vol. 10, No. 1, January 2003 ( 2003) The IEEE 802.11 Distributed Coordination Function in Small-Scale Ad-Hoc Wireless LANs Eustathia Ziouva and Theodore
More informationSRN Model for IEEE DCF MAC Protocol in Multi-hop Ad Hoc Networks with Hidden Nodes
SRN Model for IEEE 802.11 DCF MAC Protocol in Multi-hop Ad Hoc Networks with Hidden des Osama Younes and Nigel Thomas School of Computing Science, Newcastle University, UK Email: {Osama.Younes Nigel.Thomas}
More informationCMPE 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 informationCharacterising the Behaviour of IEEE Broadcast Transmissions in Ad Hoc Wireless LANs
University of Wollongong Research Online Faculty of Informatics - Papers (Archive) Faculty of Engineering and Information Sciences 2009 Characterising the Behaviour of IEEE 802.11 Broadcast Transmissions
More informationThe title of the publication is: The number of words: Illustrations: eleven figures and one table
The title of the publication is: IEE PROCEEDINGS COMMUNICATIONS The number of words: 7990 Illustrations: eleven figures and one table Corresponding author: Zhifei Li Center for Multimedia and Network Technology
More informationAppointed BrOadcast (ABO): Reducing Routing Overhead in. IEEE Mobile Ad Hoc Networks
Appointed BrOadcast (ABO): Reducing Routing Overhead in IEEE 802.11 Mobile Ad Hoc Networks Chun-Yen Hsu and Shun-Te Wang Computer Network Lab., Department of Electronic Engineering National Taiwan University
More informationTopics for Today. More on Ethernet. Wireless LANs Readings. Topology and Wiring Switched Ethernet Fast Ethernet Gigabit Ethernet. 4.3 to 4.
Topics for Today More on Ethernet Topology and Wiring Switched Ethernet Fast Ethernet Gigabit Ethernet Wireless LANs Readings 4.3 to 4.4 1 Original Ethernet Wiring Heavy coaxial cable, called thicknet,
More information