Padovan Sequence based Backoff Algorithm for Improved Wireless Medium Access in MANETs
|
|
- Wilfrid Day
- 6 years ago
- Views:
Transcription
1 Padovan Sequence based Backoff Algorithm for Improved Wireless Medium Access in MANETs Dalil Moad, Soufiene Djahel, and Farid Nait-Abdesselam University of Paris Descartes, France Lero, UCD School of Computer Science and Informatics, Ireland {dalil.moad, Abstract In this paper, we propose a novel Backoff scheme, dubbed Padovan Backoff Algorithm (PBA), to improve the efficiency of IEEE MAC protocol when operating in DCF mode. PBA will enable significant reduction of the number of collisions when more than one node try to access the shared wireless medium concurrently, leading to an enhanced network performance. The Binary Exponential Backoff (BEB) scheme used in IEEE has been proven to not be the optimal backoff algorithm for MANETs. This is mainly due to the exponential increase of the Contention Window (CW) size when a collision occurs, which results in picking the random backoff timer from a large interval that may lead to a longer waiting time before the node tries to retransmit again. Therefore, this waiting time for the idle medium could be important, especially in dense networks where consecutive collisions are more likely to happen, and thus causes a severe degradation of the network performance. To overcome the above issue, PBA employs a different scheme that reduces the size of CW as compared to BEB, thanks to the Padovan sequence. The obtained simulation results reveal that the PBA allows more efficient network resources utilization and outperforms the legacy BEB scheme in different scenarios. Keywords IEEE , Backoff Algorithm, MAC Protocols, Padovan Sequence, DCF Mode, MANETs, Throughput. I. INTRODUCTION Wireless networks refer to the use of radio frequency signals to share information and resources between wireless devices. The increasing popularity of such networks is mainly due to their intrinsic properties of cheap, easy and flexible deployment, self-organization and configuration etc. Among wireless networks we can mention, Wireless Local Area Networks (WLAN), Mobile Ad hoc NeTworks (MANETs) [13], Wireless Mesh Networks (WMN) [5] and Vehicular Ad Hoc Networks (VANETs) [14]. These networks can be grouped into two main classes, infrastructure based wireless networks (e.g. WLAN) and infrastructure-less networks (e.g. MANETs, VANETs (V2V communication)...). The former class requires a central unit to manage the networks unlike the latter class which does not need such unit; as the networks in this class are self-organized and selfconfigured. Nowadays, Mobile Ad hoc Networks (MANETs) have emerged as a promising wireless communication paradigm enabling wireless ad hoc communication in situations where the services ensured by both wired networks and WLAN are unavailable, such as in case of emergency, disaster and battlefield etc. The nodes in this network exchange information directly over wireless links if they are within the transmission range of each other. Otherwise, the communication is ensured by the intermediate nodes that relay the packets from the source to the destination through multi hop transmissions. Due to the rapidly changing topology of such networks and the instability of links, efficient medium access mechanisms are needed to maximize the usage of the limited shared bandwidth. IEEE protocol is well famous and widely used as main Medium Access Control (MAC) protocol in wireless networks which have seen an unprecedented market expansion during the last decade. IEEE [4], known as Wi-FI for its widely used IEEE802.11b specification, is currently the dominant standard for medium access in wireless networks. In IEEE based Mobile Ad Hoc Networks (MANETs), communication between two adjacent nodes (i.e. within transmission range of each other) is carried out directly, while farthest nodes can avail from an extended coverage ensured by intermediate relay nodes through multi-hop communication. The IEEE standard [3] defines a common MAC layer that offers various functions supporting wireless access operations. In general, this layer establishes, manages and maintains communication between IEEE nodes (i.e. nodes equipped with wireless cards) by coordinating their access to the shared radio channel and employing protocols that improve the communication over the shared wireless medium. Often considered as the cornerstone and brain of the network, IEEE MAC layer employs a dedicated physical layer, such as b/g/ac/ad etc., to perform several tasks such as carrier sensing, transmission, and reception of IEEE frames. IEEE MAC protocol provides two types of access modes: Distributed Coordination Function (DCF) and Point Coordination Function (PCF). In the first mode, Carrier Sensing Multiple Access with Collision Avoidance (CSMA/CA) is used as a primary access mechanism, and it is designed to support best effort traffic that does not require any specific service guarantees. In the second optional access mode (i.e. PCF), the access point plays a major role by performing a polling through which it determines which station is allowed to transmit resulting in a contention-free communication. PCF mode is usually preferred in scenarios/applications requiring strict QoS guarantees. As stated above, PCF is an optional access mode that can be utilized only in the presence of an access point, concurrently with DCF mode. Since the focus in this paper is on MANETs, therefore DCF mode will be used as the main access scheme of all the nodes in the network. In this mode, a node shall ensure that the medium is idle before attempting to transmit a data or control frame. It picks a random backoff value smaller than or equal to the current contention window (CW) size, and decrements the backoff timer by one after each time slot when the medium is idle. A node may also wait for DIFS (DCF Inter Frame Space) time slots after a successful transmission or EIFS (extended inter frame space) period in case of collision. If the medium is found busy, the node freezes its backoff timer and sets its network allocation vector (NAV) to the expected duration of transmission indicated in the received frame (i.e. RTS, CTS or DATA frames). Transmission should start whenever the backoff timer reaches zero. These different steps are summarized in Figure 1. If a CTS (Clear To Send) or an ACK (ACKnowledgement) frames associated with a DATA packet are not received within a predefined period of time (i.e. timeout), then the sender node assumes that the transmission was failed. A transmission failure, such as collision, triggers the backoff procedure which consists in selecting
2 a random waiting time chosen in the range of the current contention window (CW). After each successful transmission, the size of CW is initialized to CW min, while it is doubled in case of an unsuccessful transmission attempt. When the CW reaches CW max it remains unchanged till it is reset to CW min after reaching the number of retransmission limit or the DATA packet is delivered successfully to the intended receiver node. While it is commonly established that CW size is crucial and playing a key role in improving the overall network performance, it still presents certain limitations as doubling it in case of unsuccessful transmission may not be the most efficient way to ensure better performance, especially in dense network scenarios. Indeed, the unnecessary idleness of the medium causes the deterioration of the network performance as more packets could be transmitted over the channel during the idle unused slots where the nodes are decrementing their relatively large backoff values due to the exponential increase of CW size. Therefore, In the light of the above observations, we propose in this paper to use silver ratio of Padovan sequence to set and update the size of CW, instead of using the Binary Exponential Backoff (BEB) scheme, aiming to combat the devastating effect of the idleness resulted from the doubling the CW size after each collision. The proposed Padovan algorithm design relies on the Padovan sequence that is characterized by a plastic ratio or silver ratio as it will explained in next sections. The remainder of the paper is organized in the following way. Section II is devoted to the background and the related work on the Backoff algorithms design. The detailed description of our proposed algorithm is then introduced in section III, followed by the performance evaluation and simulation results in section IV. Finally, Section V concludes the paper. Figure 1: DCF mode: CSMA/CA scheme basic mechanism II. RELATED WORK The control of the access to the shared wireless media is ensured by the Media Access Control (MAC) protocols. Binary Exponential Backoff (BEB) [12] is the most widely used algorithm in distributed MAC protocols category. It is mainly used to avoid collisions or at least reduce their number when more than one wireless node attempt to transmit simultaneously. In IEEE MAC protocol operating under DCF mode, the nodes willing to transmit a frame wait for the channel to become free before they start the transmission, as described in Figure 1. According to the outcome of the transmission the CW of IEEE is updated by the BEB algorithm as described in the following. In BEB based DCF mode, at any given time, only one transmitting node uses channel while other nodes in its transmission or carrier sensing range defer their transmission as they sense a busy medium. Similarly, the nodes within the transmission range of the receiver node will defer their transmission when they receive the CTS (Clear to Send) frame. Before accessing the medium, each node waits for DIFS time slots and a random backoff time (Bo) uniformly distributed in the interval [0, CW]. The CW is an integer whose range (i.e. CWmin and CWmax) is determined by the physical layer characteristics. Every node decreases its backoff timer by one every time slot if the medium is still idle, and freezes it if any activity is detected on the medium, and resumes it when the medium is sensed idle again for a period equals to DIFS. Transmission shall start whenever the backoff timer counter reaches zero. If the destination node receives the RTS (Data) frame properly, it sends back a CTS (ACK) after a Short InterFrame Space (SIFS) period. If either CTS or ACK frames are not received by the sender after a predefined timeout value the sender node concludes that the previous transmission (RTS or Data frames transmission) was failed, and updates its current CW size according to BEB algorithm as described below, then after an Extended InterFrame Space (EIFS), the node selects a new backoff timer. After each failed transmission, the CW is doubled up to a maximum value of CW max. CW new = min[2 (CW old + 1) 1, CW max] (1) Random backoff value (Bo) is calculated as follows: Bo = random(0, CW ) SlotT ime. (2) Such that Bo is a random variable uniformly distributed in the interval [0, CW-1]. To improve the efficiency of the BEB algorithm discussed above a number of novel backoff calculation schemes have been proposed in the literature. In the following, we summarize the most significant contributions in this context. Multiplicative Increase and Linear Decrease (MILD) algorithm [6] and the Linear Multiplicative Increase and Linear Decrease (LMILD) [9] algorithm are among the pioneer works proposed to enhance IEEE efficiency. In LMILD, the nodes involved in a packet collision increase their contention windows multiplicatively, while the nodes that overhear this collision increase their contention windows linearly. After a successful transmission, all the nodes decrease their contention windows linearly. In MILD, once a collision occurs, instead of doubling the CW, this latter is increased by a multiplicative factor equals to 1.5. Moreover, upon successful transmission after a collision the CW is linearly decreased. Both schemes achieve significant improvement of the throughput under the assumption that the nodes are aware of the collided packets in their transmission ranges. However, this assumption is very difficult to satisfy in real world, especially in highly dense MANETs scenarios. In [7], the authors propose to dynamically tune the contention window and approximate the backoff value by p-persistent backoff. This latter is calculated based on the estimation of the number of active nodes in the network, which doesn t match a real network scenario. The Enhanced Distributed Channel Access (EDCA) scheme is proposed in [1] to improve the performance of the DCF function by providing certain levels of QoS according to the type of traffic
3 Algorithm 1 Padovan Backoff Algorithm 1: if (The medium is sensed idle more than DIFS) then 2: Send MAC frame 3: end if 4: if (retry-count==0) then 5: max-backoff = CW min 6: else 7: max-backoff = P(retry-count) 8: end if 9: if (max-backoff > CW max ) then 10: max-backoff = CW max 11: end if 12: backoff = Random (0,max-backoff) max-backoff: Backoff s upper bound. CW min : Minimum contention window. CW max : Maximum contention window. backoff: Backoff timer. P(retry-count): Padovan term. retry-count: Retransmission number. to be transmitted. The performance enhancement is achieved by offering prioritized access to different classes of traffic. EDCA mechanism defines 4 access categories each of which is assigned a CWmin,CWmax and Arbitrary Inter-Frame Space (AIFS) value which corresponds to DIFS in BEB. This mechanism is mainly designed to support traffic types with high requirements in terms of QoS such as video and audio packets. Besides the aforementioned pioneer schemes, some recent works have further investigated the BEB algorithm and designed alternative schemes to further improve the network performance. Among these works, [15] for example dealt with the increasing number of collision in dense networks and proposed the so-called Constrained-send DCF (CDCF) to limit the transmission probability of the competing nodes, and thus reduce the collision probability. In [16], the authors designed the Dynamic Contention Window Adjustment (DCWA) scheme to ensure that the maximum throughput can be achieved (approached) under saturated load conditions. Finally, in [8], a comparative study between standard DCF algorithm and Power Line Communication (PLC) MAC protocol is carried out under different network scenarios (e.g. topologies with hidden and exposed nodes, all the network nodes in the same coverage etc.). The obtained results show that PLC MAC outperforms DCF MAC. III. THE PROPOSED SOLUTION In this section, we present our MAC protocol in which we use Padovan sequence to design a new Backoff calculation scheme. As explained above, in BEB algorithm when a collision occurs the first response is to increase the contention window (CW) size exponentially (i.e. a node doubles its CW), which introduces unnecessary idle time in the channel and thus reduces the network overall performance. We, therefore, argue that doubling the contention window is not always the best or optimal solution to deal with the packets collision problem because the backoff time chosen from the new CW could be larger than the required waiting time to ensure collision free medium access. Therefore, we propose in the following the Padovan sequence based backoff scheme summarized in Algorithm 1 to ensure better management of the CW size. The Padovan sequence is the sequence of integers P(n) defined by the following initial values: P (0) = P (1) = P (2) = 1 (3) The recurrence relation is given below: P (n) = P (n 2) + P (n 3), n >= 3. (4) P (n + 1)/P (n) = (5) The main characteristic of Padovan sequence is the plastic number [10] which is also referred to as the silver number, but this name is more commonly used for the silver ratio (1 + 2). In mathematics, the plastic number is a mathematical constant which represents the unique real solution of the equation 6. x 3 = x + 1 (6) In 1928, Dom Hans van der Laan gave the name plastic number to this mathematical constant. The word plastic does not refer to a specific substance, but means something that can be given a threedimensional shape. This is because, according to Padovan [10], the characteristic ratios of the numbers, 3/4 and 1/7, relate to the limits of human perception in relating one physical size to another. This value is obtained by dividing the term (N+1) of Padovan sequence by the term N, as shown in Figure 3. This figure shows the evolution of the plastic number while Figure 2 depicts the increment behavior used in PBA and BEB. In Figure 3, we can clearly observe that after certain number of terms of the sequence, the ratio tends to a fixed number equals to 1, Figure 2 shows the evolution of the size of CW generated by BEB (see the blue curve) and PBA (see the red curve) in case of successive collisions (i.e. successive unsuccessful transmissions), and highlights that PBA can reach the CW max after larger number of retransmissions as compared to BEB in which the CW reaches the maximum value after a few attempts only. This means that the wireless nodes using PBA can get faster access to the medium and, therefore, a better utilization of the available bandwidth can be achieved. However, the slow evolution of CW size in PBA may result in an increased collision probability in case of large number of contending nodes within transmission range of each other. The Algorithm 1 describes the detailed functioning of our proposed Padovan Backoff Algorithm. In this algorithm, each node increases its CW up to the maximum contention value CW max after an unsuccessful transmission, and resets it to a minimum value equals to CW min after a successful transmission according to the following formulas: CW new = { min(p CWold, CW max) if collision CW min if success Where P represents the Padovan number. While CW is updated, the backoff timer value Bo is calculated as follows: (7) Bo = random(0; CW ) SlotT ime (8) The recurrence relation can be then solved explicitly, given that: P(n) = ((1 + r 1) / (r n+2 1 (2+3r 1))) + ((1 + r 2) / (r n+2 2 (2+3r 2))) + ((1 + r 3) / (r n+2 3 (2+3r 3))) where r i is the i th root of: x 3 +x 2-1=0. Even the other form of the solution can be also calculated as explained below: P(n)=((r 2 1)(r 3 1)r n 1 )/((r 1 r 2)(r 1 r 3))+((r 1 1)(r 3 1)r n 2 )/((r 2 r 1)(r 2 r 3)) +((r 1 1)(r 2 1)r n 3 )/((r 1 r 3)(r 2 r 3))
4 bandwidth among the contending wireless nodes, and thus if it can be adopted in real wireless cards or not. The FI is defined as follows: Figure 2: Contention window size vs. consecutive transmission failures in PBA Figure 3: Plastic number evolution where r i is the i th root of x 3 -x-1=0. IV. SIMULATION SETTING AND RESULTS After describing the details of our proposed scheme in previous sections, we now focus on evaluating its performance through computer simulations using OPNET 14.0 [2]. The main goal of our simulation is to study the efficiency of our algorithm compared to Binary Exponential Backoff algorithm. To implement our Backoff algorithm, the IEEE MAC implementation in OPNET has been modified to include the functionality of our proposal. Moreover, various simulation scenarios (network topologies and nodes mobility) are considered in the performance evaluation so as to show the benefits behind using Padovan ratio to update the CW size. In our simulation, the network size varies between 20 and 100 mobile nodes and their mobility speed varies from 2m/s to 10m/s. In order to highlight the strength of our scheme as compared to the standard BEB algorithm we have chosen to evaluate the following metrics. Normalized THroughput (NTH): the NTH of a node id is defined as follows: N throughput = T hroughput id Availablebandwidth This metric is measured for all simulation scenarios under both PBA and BEB. It is indeed a good indicator to compare the efficiency of these two algorithms. Fairness Index (FI): this metric is introduced by Jain in [11] and is considered as an important property that allows us to verify whether our PBA scheme can guarantee a fair share of (9) F I(T h1, T h2,...t hn) = NX( T i hi)2 T i h2 i (10) where Thi denotes the acquired throughput of a traffic flow (i.e. node if we have one traffic flow only per node) i and N is the number of the contending flows. Note that if only M of N flows acquire equal bandwidth (while other flows get none), then the FI is M. Hence, an F I value close to 1 indicates that PBA is N respecting the fairness property. Now, we present the simulation setting and configuration of the different parameters used in our experiments to assess the performance of PBA and BEB. Our simulation is conducted using CBR traffic during 300 seconds, which is a duration long enough to capture the behavior of our proposed scheme under different scenarios. Simulation settings and parameters configuration are summarized in table I. Parameters Values Area 1000 X 1000 square meters Physical layer Direct sequence MAC protocol IEEE b Transmission range 250m Traffic type CBR Topology Random Data rate 11 mbps CBR packets size 500 bytes Simulation time 300 seconds Slot time 20E-06s SIFS 10E-06s DIFS 50E-06s No. of simulation epochs 5 Network simulator OPNET 14.0 [2] Table I: Simulation settings In Figure 4, the NTH acquired by each sender node is plotted. The results shown reveal that the achieved average normalized throughput is much higher in case of small number of senders (i.e. less than 40 senders) while it decreases when the number of senders gets larger (i.e. more than 40 senders). Inn this latter case, each sender node gets almost half of the bandwidth acquired in the former scenario where the network is relatively of small size (i.e. less than 40 nodes). Since the network topology is randomly deployed then it is composed of separated dense clusters of nodes connected among them, hence the throughput gained within each set is independent from that acquired in other sets. We can also observe from these results that the our PBA scheme outperforms the BEB scheme under all simulated scenarios. To assess the impact of the network density on the performance of both PBA and BEB schemes in terms of throughput, we vary the number of nodes between 20 and 100 as shown in Figure 5. The results graphed in this figure clearly highlight the supremacy of PBA over BEB under various network densities as the average throughput gained by each node in the network has increased significantly in our scheme (see the blue curve) compared to that obtained in BEB (see the red curve). The increase of the throughput achieved in our scheme is due to the reduction of the unnecessary time that nodes must wait to access the medium, thanks to the Padovan sequence. This throughput, however, is inversely proportional to the network density as under high network density the number of contending nodes within the same transmission range increases significantly, leading lo lower throughput. As the gained throughput by each node may also vary according to the speed at which the node is moving, therefore we plot in Figure
5 Figure 4: Normalized throughput vs. the number of sender nodes in the network Figure 6: Average network throughput under varying mobility speed of nodes: case of network size equals to 20 Figure 5: Impact of network size on the obtained average network throughput Figure 7: Average network delay vs. network size 6 the measured average throughput in a network of 20 nodes under a mobility speed ranging from 2 m/s to 10 m/s. The results shown in this figure indicate a gap of approximately 70 kbps between PBA and BEB, which represents a substantial improvement of PBA over BEB. These results reveal also that PBA is more sensitive to the mobility speed compared to BEB as the acquired throughput under PBA decreases slightly when the nodes move faster (i.e. at a speed higher than 4m/s). However, even under higher mobility PBA still outperforming BEB as it guarantees a higher throughput (the gap is still around 55 kbps). In Figure 7, we compare the average transmission delay achieved by both schemes.as we can see from the graphed results, PBA achieves lower or similar delay compared to BEB in most simulation scenarios. This is justified by the fact that when BEB is used, in case of collision a long idle time is observed, which consequently increases the average delay in the network, as opposed to PBA which use Padovan sequence to lower this idle time as much as possible. It is also worth to mention that the average delay achieved both PBA and BEB schemes is inversely proportional to the network size. The Figure 8 plots the Fairness Index (FI) values measured under both our scheme and BEB scheme in a random network topology and under varying number of the sender nodes ( ). The depicted results highlight that both schemes achieve similar fairness level which is close to 1 in most cases. Hence, this proves that using Padovan sequence to manage the CW size ensures the fair share of the bandwidth among the competing wireless nodes. V. CONCLUSION In this paper, we have proposed a novel backoff computation scheme that ensures a significant improvement in the efficiency of IEEE MAC protocol operating in DCF mode, especially in Figure 8: Fairness index: our scheme vs. BEB dense MANETs scenarios. It is well known that IEEE BEB scheme is not an optimal backoff algorithm, especially in dense networks, because the exponential increase of the Contention Window (CW) size after each unsuccessful transmission may result in an under-utilization of the channel bandwidth. Therefore, the network performance may experience a severe degradation. To overcome the above limitation of BEB, we have devised an original backoff mechanism based on Padovan sequence in which the CW is updated according to the evolution of the Plastic number rather than doubling its value as in BEB. The obtained simulation results reveal that the Padovan Backoff Algorithm (PBA) ensures more efficient network resources utilization and outperforms the legacy BEB scheme under various scenarios. These results highlight also that PBA achieves higher throughput compared to BEB, especially in dense network scenarios, and maintains the fairness index close to 1.
6 VI. ACKNOWLEDGMENTS This work was supported, in part, by Science Foundation Ireland grant 10/CE/I1855 to Lero - the Irish Software Engineering Research Centre ( REFERENCES [1] Ieee e task group 2005 wireless lan medium access control (mac) and physical layer (phy) specifications amendment 8: Medium access control (mac) quality of service enhancements. ieee e standard. [2] Opnet technologies. (OPNET Modeler). [3] Ieee wireless lan media access control (mac) and physical layer (phy) specifications. [4] wireless lan media access control (mac) and physical layer (phy) specifications, ieee std [5] AKYILDIZ, I., AND WANG, X. A survey on wireless mesh networks. Communications Magazine, IEEE 43, 9 (Sept 2005), pp. S23 S30. [6] BHARGHAVAN, V., DEMERS, A., SHENKER, S., AND ZHANG, L. Macaw: A media access protocol for wireless lan s. SIGCOMM Comput. Commun. Rev. 24, 4 (Oct. 1994), pp [7] CALI, F., CONTI, M., AND GREGORI, E. Dynamic tuning of the ieee protocol to achieve a theoretical throughput limit. Networking, IEEE/ACM Transactions on 8, 6 (Dec 2000), pp [8] CANO, C., AND MALONE, D. Evaluation of the backoff procedure of homeplug mac vs. dcf. In Personal Indoor and Mobile Radio Communications (PIMRC), 2013 IEEE 24th International Symposium on (Sept 2013), pp [9] LI, T., TANG, T., AND CHANG, C. A new backoff algorithm for ieee distributed coordination function. Fuzzy Systems and Knowledge Discovery, FSKD 09. Sixth International Conference on 3 (Aug 2009), pp [10] PADOVAN, R. Dom hans van der laan and the plastic number [11] R. JAIN, G. BABIC, B. N., AND LAM, C. Fairness, call establishment latency and other performance metrics. Technical Report ATM Forum/ , ATM Forum Document (Aug. 1996). [12] RAZAFINDRALAMBO, T., AND VALOIS, F. Performance evaluation of backoff algorithms in ad-hoc networks. Proceedings of the 3rd ACM International Workshop on Performance Evaluation of Wireless Ad Hoc, Sensor and Ubiquitous Networks (2006), pp [13] RUBINSTEIN, M., MORAES, I., CAMPISTA, M., COSTA, L., AND DUARTE, O. A survey on wireless ad hoc networks. Mobile and Wireless Communication Networks 211 (2006), pp [14] TOOR, Y., MUHLETHALER, P., AND LAOUITI, A. Vehicle ad hoc networks: applications and related technical issues. Communications Surveys Tutorials, IEEE 10, 3 (Third 2008), pp [15] WANG, G., ZHONG, X., MEI, S., AND WANG, J. A new constrainedsend mechanism to enhance the performance of ieee dcf. In Communications and Networking in China (CHINACOM), th International ICST Conference on (Aug 2011), pp [16] YU, Q., ZHUANG, Y., AND MA, L. Dynamic contention window adjustment scheme for improving throughput and fairness in ieee wireless lans. In Global Communications Conference (GLOBECOM), 2012 IEEE (Dec 2012), pp
Medium 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 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 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 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 Comparative Analysis on Backoff Algorithms to Optimize Mobile Network
Available Online at www.ijcsmc.com International Journal of Computer Science and Mobile Computing A Monthly Journal of Computer Science and Information Technology IJCSMC, Vol. 3, Issue. 7, July 2014, pg.771
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 informationPessimistic Backoff for Mobile Ad hoc Networks
Pessimistic Backoff for Mobile Ad hoc Networks Saher S. Manaseer Department of computing science Glasgow University saher@dcs.gla.ac.uk Muneer Masadeh Department of Computer Science Jordan University of
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 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 informationMedia Access Control in Ad Hoc Networks
Media Access Control in Ad Hoc Networks The Wireless Medium is a scarce precious resource. Furthermore, the access medium is broadcast in nature. It is necessary to share this resource efficiently and
More informationPerformance analysis of Internet applications over an adaptive IEEE MAC architecture
Journal of the Franklin Institute 343 (2006) 352 360 www.elsevier.com/locate/jfranklin Performance analysis of Internet applications over an adaptive IEEE 802.11 MAC architecture Uthman Baroudi, Mohammed
More informationEmpirical Study of Mobility effect on IEEE MAC protocol for Mobile Ad- Hoc Networks
Empirical Study of Mobility effect on IEEE 802.11 MAC protocol for Mobile Ad- Hoc Networks Mojtaba Razfar and Jane Dong mrazfar, jdong2@calstatela.edu Department of Electrical and computer Engineering
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 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 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 informationEvaluation of the backoff procedure of Homeplug MAC vs. DCF
Evaluation of the backoff procedure of Homeplug MAC vs. DCF Cristina Cano and David Malone Hamilton Institute National University of Ireland, Maynooth Co. Kildare, Ireland Email: {cristina.cano,david.malone}@nuim.ie
More informationThe MAC layer in wireless networks
The MAC layer in wireless networks The wireless MAC layer roles Access control to shared channel(s) Natural broadcast of wireless transmission Collision of signal: a /space problem Who transmits when?
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 informationAccountability of WMNs using BEB Algorithm
Accountability of WMNs using BEB Algorithm Shafi Jasuja Department of Information Technology Chandigarh Engineering College, Landran, Mohali, Punjab, India Parminder Singh Department of Information Technology
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 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 informationICE 1332/0715 Mobile Computing (Summer, 2008)
ICE 1332/0715 Mobile Computing (Summer, 2008) Medium Access Control Prof. Chansu Yu http://academic.csuohio.edu/yuc/ Simplified Reference Model Application layer Transport layer Network layer Data link
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 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 informationA Novel Framework for Radio Resource Management in IEEE Wireless LANs
Dublin Institute of Technology ARROW@DIT Conference papers Communications Network Research Institute 2005-01-01 A Novel Framework for Radio Resource Management in IEEE 802.11 Wireless LANs Mark Davis Dublin
More informationIEEE , 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 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 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 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 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 informationAn Efficient Backoff Algorithm for QoS Guaranteeing in Wireless Networks
An Efficient Backoff Algorithm for QoS Guaranteeing in Wireless Networks Xinhua Liu, Guojun Ma, HaiLan Kuang, Fangmin Li School of Information Engineering, Wuhan University of Technology, Wuhan, 430070
More informationUnit 7 Media Access Control (MAC)
Unit 7 Media Access Control (MAC) 1 Internet Model 2 Sublayers of Data Link Layer Logical link control (LLC) Flow control Error control Media access control (MAC) access control 3 Categorization of MAC
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 informationCSMA 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 informationE-BEB Algorithm to Improve Quality of Service on Wireless Ad-Hoc Networks
Research Journal of Applied Sciences, Engineering and Technology 4(7): 807-812, 2012 ISSN: 2040-7467 Maxwell Scientific Organization, 2012 Submitted: vember 10, 2011 Accepted: December 09, 2011 Published:
More informationThe MAC layer in wireless networks
The MAC layer in wireless networks The wireless MAC layer roles Access control to shared channel(s) Natural broadcast of wireless transmission Collision of signal: a time/space problem Who transmits when?
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 informationMedium 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 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 informationECE442 Communications Lecture 3. Wireless Local Area Networks
ECE442 Communications Lecture 3. Wireless Local Area Networks Husheng Li Dept. of Electrical Engineering and Computer Science Spring, 2014 Wireless Local Networks 1 A WLAN links two or more devices using
More informationProject Report: QoS Enhancement for Real-Time Traffic in IEEE WLAN
Project Report: QoS Enhancement for Real-Time Traffic in IEEE802.11 WLAN Abstract A key issue in IEEE802.11 WLAN MAC is how to provide QoS support, especially for time-bounded traffic. Although much work
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 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 informationChapter 12 Multiple Access 12.1
Chapter 12 Multiple Access 12.1 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 12.2 Figure 12.1 Data link layer divided into two functionality-oriented sublayers
More informationAn Approach for Improving Performance of Back off Algorithm
International Journal of Computer Applications (975 8887) Volume 46 No.5, May 212 An Approach for Improving Performance of Back off Algorithm Swati Bhagoria Computer Engineering Department Shri G.S. Institute
More informationAchieving MAC Fairness in Wireless Ad-hoc Networks using Adaptive Transmission Control
Achieving MAC Fairness in Wireless Ad-hoc Networks using Adaptive Transmission Control Zhifei Li School of Computer Engineering Nanyang Technological University Singapore, 639798 Sukumar Nandi Dept. of
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 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 informationA Directional MAC Protocol with the DATA-frame Fragmentation and Short Busy Advertisement Signal for Mitigating the Directional Hidden Node Problem
2012 IEEE 23rd International Symposium on Personal, Indoor and Mobile Radio Communications - (PIMRC) A Directional MAC Protocol with the DATA-frame Fragmentation and Short Busy Advertisement Signal for
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 informationCooperative Communication Protocol based on Relay Node Grouping in Wireless Networks
Cooperative Communication Protocol based on Relay Node Grouping in Wireless Networks Sunmyeng Kim Department of Computer Software Engineering, Kumoh National Institute of Technology 1 Daehak-ro, Gumi,
More informationVHDL Modeling of the CSMA/CA
VHDL Modeling of the CSMA/CA W.L. Pang, K. W. Chew, Florence Choong, E.S. Teoh Abstract The wireless communication is highly deployed due to it convenience of mobility. The wireless local area network,
More informationAnalyzing the Impact of DCF and PCF on WLAN Network Standards a, b and g
Analyzing the Impact of DCF and PCF on WLAN Network Standards 802.11a, 802.11b and 802.11g Amandeep Singh Dhaliwal International Science Index, Computer and Information Engineering waset.org/publication/9996677
More information04/11/2011. Wireless LANs. CSE 3213 Fall November Overview
Wireless LANs CSE 3213 Fall 2011 4 November 2011 Overview 2 1 Infrastructure Wireless LAN 3 Applications of Wireless LANs Key application areas: LAN extension cross-building interconnect nomadic access
More informationA Novel Contention Window Control Scheme Based on a Markov Chain Model in Dense WLAN Environment
05 Third International Conference on Artificial Intelligence, Modelling and Simulation A Novel Contention Window Control Scheme Based on a Markov Chain Model in Dense WLAN Environment Yoshiaki Morino,
More informationWireless Local Area Networks (WLANs)) and Wireless Sensor Networks (WSNs) Computer Networks: Wireless Networks 1
Wireless Local Area Networks (WLANs)) and Wireless Sensor Networks (WSNs) Computer Networks: Wireless Networks 1 Wireless Local Area Networks The proliferation of laptop computers and other mobile devices
More informationWireless Local Area Networks. Networks: Wireless LANs 1
Wireless Local Area Networks Networks: Wireless LANs 1 Wireless Local Area Networks The proliferation of laptop computers and other mobile devices (PDAs and cell phones) created an obvious application
More informationInternational Journal of Technical Research and Applications e-issn: , Special, Issue 43 (March 2017), PP.
COMPARATIVE STUDY OF DIFFERENT BACKOFF ALGORITHMS IN IEEE 802.11 DCF MAC PROTOCOL 1 Aditi Harugade, 2 Priyanka Karunglikar, 3 Damini Jadhav, 4 Prem Kumar, 5 T.N. Sawant 1,2,3,4,5 Electronics and Telecommunication
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 informationstandard. Acknowledgement: Slides borrowed from Richard Y. Yale
802.11 standard Acknowledgement: Slides borrowed from Richard Y. Yang @ Yale IEEE 802.11 Requirements Design for small coverage (e.g. office, home) Low/no mobility High data rate applications Ability to
More informationCS 348: Computer Networks. - WiFi (contd.); 16 th Aug Instructor: Sridhar Iyer IIT Bombay
CS 348: Computer Networks - WiFi (contd.); 16 th Aug 2012 Instructor: Sridhar Iyer IIT Bombay Clicker-1: Wireless v/s wired Which of the following differences between Wireless and Wired affect a CSMA-based
More informationPerformance Analysis for Channel Utilization in Wireless LAN
Performance Analysis for Channel Utilization in Wireless LAN Shweta Singh Naresh Chandra Arun Kumar Tripathi ABSTRACT Wireless network plays an important role in field of communication. Now a days people
More informationCHAPTER 5 PROPAGATION DELAY
98 CHAPTER 5 PROPAGATION DELAY Underwater wireless sensor networks deployed of sensor nodes with sensing, forwarding and processing abilities that operate in underwater. In this environment brought challenges,
More information6.9 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 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 informationInternational Journal of Emerging Technology and Advanced Engineering Website: (ISSN , Volume 2, Issue 1, January 2012)
Performance Improvement of 802.11 MAC by enhancements in DCF Vikram Jain 1, Siddharth Dutt Choubey 2, Rohit Singh 3, Sandeep Gupta 4 1 Research Scholar, Singhania University, INDIA 2,3,4 ME / MTech (CS
More informationSimulation Based Analysis of the Impact of Hidden Terminal to the TCP Performance in Mobile Ad Hoc Networks
Simulation Based Analysis of the Impact of Hidden Terminal to the TCP Performance in Mobile Ad Hoc Networks Abstract The hidden terminal is classified as the sending hidden terminal and receiving hidden
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 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 informationTransmission Control Protocol over Wireless LAN
Global Journal of Computer Science and Technology Network, Web & Security Volume 12 Issue 17 Version 1.0 Year 2012 Type: Double Blind Peer Reviewed International Research Journal Publisher: Global Journals
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 informationInvestigating MAC-layer Schemes to Promote Doze Mode in based WLANs
Investigating MAC-layer Schemes to Promote Doze Mode in 802.11-based WLANs V. Baiamonte and C.-F. Chiasserini CERCOM - Dipartimento di Elettronica Politecnico di Torino Torino, Italy Email: baiamonte,chiasserini
More informationWireless MACs: MACAW/802.11
Wireless MACs: MACAW/802.11 Mark Handley UCL Computer Science CS 3035/GZ01 Fundamentals: Spectrum and Capacity A particular radio transmits over some range of frequencies; its bandwidth, in the physical
More informationImpact of IEEE n Operation on IEEE Operation
2009 International Conference on Advanced Information Networking and Applications Workshops Impact of IEEE 802.11n Operation on IEEE 802.15.4 Operation B Polepalli, W Xie, D Thangaraja, M Goyal, H Hosseini
More informationIEEE p Performance Evaluation and Protocol Enhancement
IEEE 8.11p Performance Evaluation and Protocol Enhancement Yi Wang, Akram Ahmed, Bhaskar Krishnamachari and Konstantinos Psounis Viterbi School of Engineering University of Southern California Los Angeles,
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 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 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 informationTurning Hidden Nodes into Helper Nodes in IEEE Wireless LAN Networks
Turning Hidden Nodes into Helper Nodes in IEEE 82.11 Wireless LAN Networks 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 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 informationDynamic Power Control MAC Protocol in Mobile Adhoc Networks
Dynamic Power Control MAC Protocol in Mobile Adhoc Networks Anita Yadav Y N Singh, SMIEEE R R Singh Computer Science and Engineering Electrical Engineering Computer Science and Engineering Department Department
More informationSaturated Throughput Analysis of IEEE e EDCA
Saturated Throughput Analysis of IEEE 80.e EDCA Lixiang Xiong, Guoqiang Mao School of Electrical and Information Engineering The University of Sydney, Sydney, NW 006, Australia Abstract IEEE 80.e standard
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 informationPerformance Improvement In MANET By Using A Modified BEB Algorithm
Performance Improvement In MANET By Using A Modified BEB Algorithm Aparna S. Mankar 1, Mangla S. Madankar 2 1 ME Student, Wireless Communication & Computing, GHRCE Nagpur 2 Assistant Professor, Department
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 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 informationA Performance Analysis of IEEE Networks in the Presence of Hidden Stations
A Performance Analysis of IEEE 802.11 Networks in the Presence of Hidden Stations Marek Natkaniec, Andrzej R. Pach University of Mining and Metallurgy, Department of Telecommunications, Cracow, Poland
More informationConcurrent-MAC: Increasing Concurrent Transmissions in Dense Wireless LANs
Concurrent-MAC: Increasing Concurrent Transmissions in Dense Wireless LANs Ghazale Hosseinabadi and Nitin Vaidya Department of ECE and Coordinated Science Lab. University of Illinois at Urbana-Champaign
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 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 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 informationA new Traffic Separation Mechanism (TSm) in Wireless e Networks: A simulation study
A new Traffic Separation Mechanism (TSm) in Wireless 802.11e Networks: A simulation study Ricardo Moraes 1, Francisco Vasques 1, Paulo Portugal 1, José Alberto Fonseca 2 1 Faculdade de Engenharia Universidade
More informationCertified Wireless Network Administrator (CWNA) PW Chapter Medium Access. Chapter 8 Overview
Certified Wireless Network Administrator (CWNA) PW0-105 Chapter 8 802.11 Medium Access Chapter 8 Overview CSMA/CA vs. CSMA/CD Distributed Coordination Function (DCF) Point Coordination Function (PCF) Hybrid
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 informationCSCD 433 Network Programming Fall Lecture 7 Ethernet and Wireless
CSCD 433 Network Programming Fall 2016 Lecture 7 Ethernet and Wireless 802.11 1 Topics 802 Standard MAC and LLC Sublayers Review of MAC in Ethernet MAC in 802.11 Wireless 2 IEEE Standards In 1985, Computer
More informationEVALUATION OF BACK-OFF ALGORITHM PERFORMANCE OF MAC LAYER IEEE WLAN
EVALUATION OF BACK-OFF ALGORITHM PERFORMANCE OF MAC LAYER IEEE 802.11 WLAN 1 Khan Tazeem Ahmad, 2 Beg M. T., & 3 Khan M. A. 1,2 Department of ECE, Faculty of Engineering & Technology, Jamia Millia Islamia,New
More informationWireless Local Area Networks (WLANs) and Wireless Sensor Networks (WSNs) Primer. Computer Networks: Wireless LANs
Wireless Local Area Networks (WLANs) and Wireless Sensor Networks (WSNs) Primer 1 Wireless Local Area Networks (WLANs) The proliferation of laptop computers and other mobile devices (PDAs and cell phones)
More informationWireless LAN -Architecture
Wireless LAN -Architecture IEEE has defined the specifications for a wireless LAN, called IEEE 802.11, which covers the physical and data link layers. Basic Service Set (BSS) Access Point (AP) Distribution
More informationCollisions & Virtual collisions in IEEE networks
Collisions & Virtual collisions in IEEE 82.11 networks Libin Jiang EE228a project report, Spring 26 Abstract Packet collisions lead to performance degradation in IEEE 82.11 [1] networks. The carrier-sensing
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 information