Announcement Traffic Indication Message Research Articles

Minimum Number of Neighbour Nodes and Transmission Range Based Overhearing Controlled Protocol for Mobile Ad-Hoc Networks

Ad-hoc networks are communications less wireless networks; the most critical problem in mobile ad-hoc networks is energy utilization. Energy could be a restricted resource. All nodes eavesdrops the data transference in its locality and uses energy without need. Nevertheless various existing routing procedures collect route information via eavesdropping. The important reason for more energy utilization is unnecessary eavesdropping and rebroadcasting of RREQ to nodes. We propose a new mechanism to decrease energy consumption called Minimum Number of Neighbor Nodes and Transmission Range Based Overhearing Controlled Protocol. In which node has a choice of whether to send a packet or not by transmit effective info in Announcement Traffic Indication Message (ATIM) window and node selection on the basis of Transmission range and RES. The Proposed protocol is high energy-efficient compared to Conventional 802.11 PSM-established projects.

An efficient multi-channel MAC protocol for wireless ad hoc networks

IEEE 802.11 MAC is designed for single channel and based on Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA). The throughput of network is limited by the bandwidth of the single channel and the CSMA-based MAC protocol with omnidirectional antennas can cause the serious unfairness or flow starvation. By exploiting the multiple channels and using the directional antennas, nodes located in each other’s vicinity may communicate simultaneously. This helps to increase the spatial reuse of the wireless channel and thus increase the network performance. In this paper, we propose a Multi-channel MAC protocol with Directional Antennas (MMAC-DA) that adopts IEEE 802.11 Power Saving Mechanism (PSM) and exploits multiple channel resources and directional antennas. Nodes have to exchange control packets during the Announcement Traffic Indication Message (ATIM) window to select data channels and determine the beam directions which are used to exchange data packets during the data window. The simulation results show that MMAC-DA can improve the network performance in terms of aggregate throughput, packet delivery ratio, energy efficiency and fairness index.

Autonomous and adaptive beaconing strategy for multi‐interfaced wireless mobile nodes

AbstractAd hoc wireless communications rely on beaconing to manage and maintain several network operations and to share relevant network parameters among network nodes. Beacon frames are sent at the start of each beacon interval. The frequency of beaconing depends on whether beacon intervals are fixed size or may be adapted and regulated according to the perceived network and workload conditions. On the other hand, current mobile nodes usually embed several heterogeneous wireless interfaces that urge the design of an adaptive beaconing strategy. In this paper, we propose an autonomous and adaptive beaconing strategy for multi‐interfaced mobile wireless nodes that is capable of regulating the beacon interval size dynamically according to the perceived network conditions. The proposed strategy is based on a joint dynamic estimation of both the announcement traffic indication message (ATIM) window and the beyond‐ATIM window sizes for each beacon interval. Extensive simulations were conducted using OMNeT++ to ascertain the improvements achieved by autonomously regulating the entire beacon interval to take into account the network and workload conditions. Obtained results showed that the two proposed approaches improve significantly the efficiency of the network in terms of throughput, end‐to‐end delay, and power consumption. The proposed fixed beacon interval (fixed‐BI) approach stands as an enhanced version of the power‐saving multi‐channel MAC protocol (PSM‐MMAC). The proposed variable beacon interval (variable‐BI) approach, which regulates dynamically both of the ATIM and the beyond‐ATIM windows, outperforms both the fixed‐BI and the PSM‐MMAC. In particular, under nominal traffic loads, the end‐to‐end delay of the variable‐BI is much lower than those provided by the fixed‐BI and PSM‐MMAC. Copyright © 2015 John Wiley & Sons, Ltd.

Performance Modeling and Analysis of IEEE 802.11 IBSS PSM in Different Traffic Conditions

The IEEE 802.11 standard for wireless local area networks defines a power management algorithm for Independent Basic Service Set (IBSS) allowing it to save critical battery energy in low powered wireless devices. The power management algorithm for IBSS uses beacon intervals (BIs) as the time unit, where every BI consists of an Announcement Traffic Indication Message (ATIM) window and a data window. The stations that have data to send need to go through a handshaking procedure in the ATIM window. If this handshaking is successful, the station remains awake in the data window and participates in the data communication. Otherwise, it goes into the sleep mode. This paper presents an analytical model to compute the throughput, expected delay and expected power consumption in an IEEE 802.11 IBSS in power save mode (PSM) for different traffic conditions in the network. The impact of data arrival rate, network size, and size of the BI on the performance of the IEEE 802.11 DCF in PSM is also analyzed. This analysis reveals a clear trade-off among throughput, delay, and average power consumption. The trade-off analysis is useful for designing efficient power consumption algorithms while maintaining the consistence performance of the network in terms of throughput and delay.

Probabilistic model checking of IEEE 802.11 IBSS power save mode

The IEEE 802.11 standard for wireless local area network defines a power management algorithm for Independent Basic Service Set (IBSS). In the power management for IBSS, time is divided into Beacon Intervals (BIs) and each BI is divided into an Announcement Traffic Indication Message (ATIM) window and a data window. The stations that have successfully transmitted an ATIM frame within the ATIM window will compete to transmit a data frame in the data window. The rest of the stations go to sleep mode during the data window, thus saving power. The power management algorithm for IBSS mode, based on a randomised exponential backoff procedure, is defined in the IEEE 802.11 standard for wireless LANs. The probabilistic behaviour of the MAC mechanism enables us to design a probabilistic model suitable for model checking. This paper presents a finite state Markov Decision Process (MDP) and uses the tool PRISM to compute the performance of the IEEE 802.11 IBSS in PSM. A set of performance properties, such as expected delay and energy consumption, is specified as queries in the probabilistic temporal logic PCTL and computed using PRISM.

Performance modeling and evaluation of IEEE 802.11 IBSS power save mode

The IEEE 802.11 standard defines a power management algorithm for wireless LAN. In the power management for Independent Basic Service Set (IBSS), time is divided into Beacon Intervals (BIs) and each BI is divided into an Announcement Traffic Indication Message (ATIM) window and a data window. The stations that have successfully transmitted an ATIM frame within the ATIM window compete to transmit data frames in the rest of the BI. This paper analyzes the performance of the IEEE 802.11 Power Save Mode (PSM) in single hop ad hoc networks using a discrete-time Markov chain for a data frame transmission together with the corresponding ATIM frame transmission. The paper presents an analytical model to compute the throughput, average delay and power consumption in IEEE 802.11 IBSS in PSM under ideal channel and saturation conditions. The impact of network size on the throughput, delay and power consumption of the IEEE 802.11 DCF in Power Save Mode is also analyzed. This can be used to find an efficient scheme that can maximize the network throughput while saving power consumption for resource constrained ad hoc wireless networks. The analytical work is validated with simulation results obtained from Qualnet 5.0.1 network simulator.

A SINR-Based MAC Protocol for Wireless Ad Hoc Networks

In this paper, we propose a power control MAC protocol that improves the spatial reuse of wireless channels and the energy efficiency for the wireless nodes. The main idea is to adopt IEEE 802.11 Power Saving Mechanism (PSM) with the appropriate power control scheme for the wireless ad hoc networks. All control messages containing the transmission power information are transmitted at the maximum transmission power in the Announcement Traffic Indication Message (ATIM) window while the data packets are sent at the minimum required transmission power during the data window. Based on the sensing power or the transmission power information of the control messages, a neighbor node checks whether it can transmit simultaneously. Simulation results show the advantages of the proposed protocol in terms of the aggregate throughput, average delay, energy efficiency and fairness index.

Traffic scheduling mechanism based on graph theory for Power Saving mode of IEEE 802.11 distributed coordinator function

In IEEE 802.11 Power Saving (PS) mode specified for Independent Basic Service Set (IBSS), mobile stations announce their pending data packets within Announcement Traffic Indication Message (ATIM) window immediately after the reception of Time Synchronisation Function (TSF) beacon. This paper proposed modifications to the PS mode by transmitting the TSF beacon at the end of each ATIM window. Upon actively overhearing the traffic announcements, a mobile station can function as the centralised coordinator by piggyback transmission scheduling information within the beacon. Different traffic scheduling mechanisms are proposed that will ensure the data packets transmission to be contention-free and minimise the total time that mobile stations have to stay in the active state. The complexity and performance of the proposed algorithms are analysed using simulation and analytical method. The results show that the proposed algorithms improve the power efficiency and performance compared with original IEEE 802.11 protocol.

Throughput and Optimal ATIM Window of IEEE 802.11 Distributed Coordination Function in Power Saving Mode

This paper analyzes the throughput and the optimal announcement traffic indication message (ATIM) window of the IEEE 802.11 Distributed Coordination Function (DCF) in the power saving mode. An analytical model based on Markov chain model is proposed to express the throughput and the optimal ATIM window in a mathematical form; it is validated by the simulation. The optimal ATIM window size is obtained to maximize the throughput and minimize the power consumption while solving the fairness problem.

An efficient cluster-based multi-channel management protocol for wireless Ad Hoc networks

In Ad Hoc networking, cluster-based communication protocol can reduce large amount of flooding packets in route establishment process. However, the 802.11 medium access control (MAC) protocol is not dedicated to cluster-based network architecture. Applying 802.11 MAC protocol to cluster-based network introduces problems of inefficient channel utilization in announcement traffic indication message (ATIM) and data sub-windows for gateway nodes, heavy channel contention in some channels, large power consumption of mobile hosts, and poor utilization of multi-channel resources. In this paper, we propose a MAC layer multi-channel management protocol which takes power saving issues into consideration in a cluster-based network topology. The proposed protocol aims at effective utilization of multi-channel bandwidth for data communications among mobile hosts. Features of the proposed protocol includes: (1) preserving the property of fair channel contention in original 802.11 protocol, (2) constructing a proper contention condition for mobile hosts, (3) reducing power consumption for idle mobile hosts, (4) reducing probability of collision and unnecessary power consumption due to heavy contention, and (5) decreasing the transmission delay of gateway node through proper management of inter-cluster traffic. Experimental results reveal that the proposed protocol has good performance in network throughputs, average transmission delay time and energy consumption.

A modified power saving mode in IEEE 802.11 distributed coordinator function

Power saving (PS) mode specified in IEEE 802.11 standard is a power efficient method that prolongs the network operation time of battery powered wireless LAN devices. It is a synchronous protocol which requires precise time synchronization among all the participating nodes within the Independent Basic Service Set (IBSS). Therefore, Time Synchronization Function (TSF) is defined for the protocol to operate without the aid of external timing sources. Time synchronization is achieved by periodically transmitting the time synchronization beacon, which will define a series of fixed length beacon intervals. In PS mode for Distributed Coordinated Function (DCF), nodes will wake up at the beginning of each beacon interval for a duration called Announcement Traffic Indication Message (ATIM) window to announce their pending data packets using small ATIM control packets. After the ATIM window, nodes will transmit the announced data packets using contention-based DCF access procedure. This paper proposes a modified mechanism by sending the TSF beacon at the end of each ATIM window and adding certain scheduling information in the beacon to schedule the transmission of announced data packets. The scheduling information will ensure the data packets transmission to be contention-free. Hence, the scheduled data packet transmission will achieve a higher throughput and lower energy consumption. Results based on simulation have shown that as much as 70% of energy saving can be achieved.