9,522 research outputs found
Fuzzy based load and energy aware multipath routing for mobile ad hoc networks
Routing is a challenging task in Mobile Ad hoc Networks (MANET) due to their dynamic topology and lack of central administration. As a consequence of un-predictable topology changes of such networks, routing protocols employed need to accurately capture the delay, load, available bandwidth and residual node energy at various locations of the network for effective energy and load balancing. This paper presents a fuzzy logic based scheme that ensures delay, load and energy aware routing to avoid congestion and minimise end-to-end delay in MANETs. In the proposed approach, forwarding delay, average load, available bandwidth and residual battery energy at a mobile node are given as inputs to a fuzzy inference engine to determine the traffic distribution possibility from that node based on the given fuzzy rules. Based on the output from the fuzzy system, traffic is distributed over fail-safe multiple routes to reduce the load at a congested node. Through simulation results, we show that our approach reduces end-to-end delay, packet drop and average energy consumption and increases packet delivery ratio for constant bit rate (CBR) traffic when compared with the popular Ad hoc On-demand Multipath Distance Vector (AOMDV) routing protocol
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
An interaction between congestion-control based transport protocols and MANET routing protocols
Problem statement: Although many efforts have been done on studying the behaviour of TCP in MANET, but the behaviour of TFRC remain unclear in MANET. The purpose of this research is two folds.First, we studied the behaviour of TFRC and TCP over AODV and DSR as the underlying routing protocols in terms of throughput, delay and jitter.The second objective was to identify whether MANET routing protocols have an impact on transport protocols or not.Approach: Network Simulator 2 (NS-2) was used to conduct all of the experiments, i.e., TFRC over AODV, TFRC over DSR, TCP over AODV and TCP over DSR.We created 30 nodes on a 1000×1000 m location area and each node was assigned CBR traffic, transport protocol and routing protocol.In order to simulate the nodes mobility, we implemented a Random Waypoint mobility model with varying speeds of 5, 10, 15 and 20 m sec−1 (m/sec) with a 10 sec pause time.Results: We observed that TFRC throughput increases almost 55% when using DSR as its routing protocol, but TCP throughput has no significant difference with different underlying protocols.However, in terms of jitter and delay, both routing protocols, i.e., AODV and DSR have the impact of more than 50% on TFRC and TCP.
Conclusion/Recommendations: The results obtained also show us that TFRC or TCP should choose
AODV as its routing protocol because it has less jitter which is one of the critical performance metrics for multimedia applications
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
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