Agent Approach QoS Routing in Manet Based on Fuzzy Priority Scheduler

As mobile computing gains popularity, the need for Ad-hoc network will continue to grow. The mobile Ad-hoc network is an autonomous system of mobile wireless nodes connected dynamically without any preexisting infrastructure. Here, the nodes are mobile, hence the network topology changes rapidly and unpredictable over time.Here we proposed the mesh based On Demand multicast Routing protocol (OMDRP), in OMDRP the mesh created by using route request and route reply packets. After the mesh we create the cluster, Clustering is a method which aggregates nodes into groups. These groups are contained within the network and they are known as clusters. In mesh we find the multipaths from source to destinations. In that multipaths again we choose one QoS path depending on minimum delay required to reach the destination. In this paper we use the fuzzy scheduling algorithm to schedule the data packets based on their respective priority index,which will improve the network performance. The presented fuzzy scheduler for mobile Ad-hoc networks,determine the priority of the packets. The proposed fuzzy logic scheduling method is simulated by using Cprogramming language. The propsed scheme is better the without fuzzy priority scheduling system

Hop-Based dynamic fair scheduler for wireless Ad-Hoc networks

In a typical multihop Ad-Hoc network, interference and contention increase when flows transit each node towards destination, particularly in the presence of cross-traffic. This paper observes the relationship between throughput and path length, self-contention and interference and it investigates the effect of multiple data rates over multiple data flows in the network. Drawing from the limitations of the 802.11 specification, the paper proposes a scheduler named Hop Based Multi Queue (HBMQ), which is designed to prioritise traffic based on the hop count of packets in order to provide fairness across different data flows. The simulation results demonstrate that HBMQ performs better than a Single Drop Tail Queue (SDTQ) scheduler in terms of providing fairness. Finally, the paper concludes with a number of possible directions for further research, focusing on cross-layer implementation to ensure the fairness is also provided at the MAC layer. © 2013 IEEE

Distributed QoS Guarantees for Realtime Traffic in Ad Hoc Networks

In this paper, we propose a new cross-layer framework, named QPART ( QoS br>rotocol for Adhoc Realtime Traffic), which provides QoS guarantees to real-time multimedia applications for wireless ad hoc networks. By adapting the contention window sizes at the MAC layer, QPART schedules packets of flows according to their unique QoS requirements. QPART implements priority-based admission control and conflict resolution to ensure that the requirements of admitted realtime flows is smaller than the network capacity. The novelty of QPART is that it is robust to mobility and variances in channel capacity and imposes no control message overhead on the network

Maximizing throughput while maintaining fairness and priority in wireless ad-hoc networks

Title from PDF of title page, viewed on March 14, 2013Thesis advisor: Cory BeardVitaIncludes bibliographic references (p. 42-43)Thesis (M.S.)--School of Computing and Engineering. University of Missouri--Kansas City, 2012Ad-Hoc wireless network, not a new field of research, has been gaining a lot of popularity in recent years because of its applications in emergency rescue, surveying, military, sensor networking, entertainment and community wireless networking etc. A lot of research has been done on improving the performance and capacity of ad-hoc networks in that period of time. However, not much has been done in the analytical modeling of inter nodal interference and its effect on transmission patterns of wireless ad-hoc network. In our work we investigated and developed a contention based ad-hoc network to study the interference impact on network performance. In our model we represented these inter nodal conflicts using 'Conflict Graph or Conflict Matrix' and presented scheduling schemes to address issues like network throughput, fairness and QoS (priority) in a network. We particularly studied the transmission patterns in a network given a specific conflict graph which in turn depends on factors like number of nodes and their placement, area of coverage, type of antenna (unidirectional or omnidirectional) etc. We designed five scheduling schemes in order to provide solutions to issues like maximizing network throughput, fairness and priority using the concept of 'Transmit Groups', which are groups of nodes that are capable of transmitting together without any interference. For simulations, we have assumed a central entity which controls and schedules packet transmission from nodes. Using MATLAB simulations, we analyzed the throughput in hundreds of sample networks which differ based on number of nodes, number of conflicts and number of high priority nodes in the network. With the help of these results we not only proved that interference is an important factor in performance of wireless ad-hoc networks , but also its impact on different aspects of network depends on the number of nodes and number of conflicts. Based on the length of longest transmit group in a network and its variation with number of nodes, we calculated the maximum throughput possible. In our QoS schemes, we compared the success rate of achieving a pre assumed relative throughput by S-D pairs.Introduction -- Background -- Scheduling schemes -- Simulations and results -- Conclusions and future wor

Interference-Aware Scheduling for Connectivity in MIMO Ad Hoc Multicast Networks

We consider a multicast scenario involving an ad hoc network of co-channel MIMO nodes in which a source node attempts to share a streaming message with all nodes in the network via some pre-defined multi-hop routing tree. The message is assumed to be broken down into packets, and the transmission is conducted over multiple frames. Each frame is divided into time slots, and each link in the routing tree is assigned one time slot in which to transmit its current packet. We present an algorithm for determining the number of time slots and the scheduling of the links in these time slots in order to optimize the connectivity of the network, which we define to be the probability that all links can achieve the required throughput. In addition to time multiplexing, the MIMO nodes also employ beamforming to manage interference when links are simultaneously active, and the beamformers are designed with the maximum connectivity metric in mind. The effects of outdated channel state information (CSI) are taken into account in both the scheduling and the beamforming designs. We also derive bounds on the network connectivity and sum transmit power in order to illustrate the impact of interference on network performance. Our simulation results demonstrate that the choice of the number of time slots is critical in optimizing network performance, and illustrate the significant advantage provided by multiple antennas in improving network connectivity.Comment: 34 pages, 12 figures, accepted by IEEE Transactions on Vehicular Technology, Dec. 201

JiTS: Just-in-Time Scheduling for Real-Time Sensor Data Dissemination

We consider the problem of real-time data dissemination in wireless sensor networks, in which data are associated with deadlines and it is desired for data to reach the sink(s) by their deadlines. To this end, existing real-time data dissemination work have developed packet scheduling schemes that prioritize packets according to their deadlines. In this paper, we first demonstrate that not only the scheduling discipline but also the routing protocol has a significant impact on the success of real-time sensor data dissemination. We show that the shortest path routing using the minimum number of hops leads to considerably better performance than Geographical Forwarding, which has often been used in existing real-time data dissemination work. We also observe that packet prioritization by itself is not enough for real-time data dissemination, since many high priority packets may simultaneously contend for network resources, deteriorating the network performance. Instead, real-time packets could be judiciously delayed to avoid severe contention as long as their deadlines can be met. Based on this observation, we propose a Just-in-Time Scheduling (JiTS) algorithm for scheduling data transmissions to alleviate the shortcomings of the existing solutions. We explore several policies for non-uniformly delaying data at different intermediate nodes to account for the higher expected contention as the packet gets closer to the sink(s). By an extensive simulation study, we demonstrate that JiTS can significantly improve the deadline miss ratio and packet drop ratio compared to existing approaches in various situations. Notably, JiTS improves the performance requiring neither lower layer support nor synchronization among the sensor nodes