761 research outputs found
Optimal Fair Scheduling in S-TDMA Sensor Networks for Monitoring River Plumes
Underwater wireless sensor networks (UWSNs) are a promising technology to provide oceanographers with environmental data
in real time. Suitable network topologies to monitor estuaries are formed by strings coming together to a sink node.This network
may be understood as an oriented graph. A number of MAC techniques can be used in UWSNs, but Spatial-TDMA is preferred
for fixed networks. In this paper, a scheduling procedure to obtain the optimal fair frame is presented, under ideal conditions
of synchronization and transmission errors. The main objective is to find the theoretical maximum throughput by overlapping
the transmissions of the nodes while keeping a balanced received data rate from each sensor, regardless of its location in the
network. The procedure searches for all cliques of the compatibility matrix of the network graph and solves a Multiple-Vector
Bin Packing (MVBP) problem. This work addresses the optimization problem and provides analytical and numerical results for
both the minimum frame length and the maximum achievable throughput
Proportional fairness in wireless powered CSMA/CA based IoT networks
This paper considers the deployment of a hybrid wireless data/power access
point in an 802.11-based wireless powered IoT network. The proportionally fair
allocation of throughputs across IoT nodes is considered under the constraints
of energy neutrality and CPU capability for each device. The joint optimization
of wireless powering and data communication resources takes the CSMA/CA random
channel access features, e.g. the backoff procedure, collisions, protocol
overhead into account. Numerical results show that the optimized solution can
effectively balance individual throughput across nodes, and meanwhile
proportionally maximize the overall sum throughput under energy constraints.Comment: Accepted by Globecom 201
An efficient scalable scheduling mac protocol for underwater sensor networks
Underwater Sensor Networks (UWSNs) utilise acoustic waves with comparatively lower loss and longer range than those of electromagnetic waves. However, energy remains a challenging issue in addition to long latency, high bit error rate, and limited bandwidth. Thus, collision and retransmission should be efficiently handled at Medium Access Control (MAC) layer in order to reduce the energy cost and also to improve the throughput and fairness across the network. In this paper, we propose a new reservation-based distributed MAC protocol called ED-MAC, which employs a duty cycle mechanism to address the spatial-temporal uncertainty and the hidden node problem to effectively avoid collisions and retransmissions. ED-MAC is a conflict-free protocol, where each sensor schedules itself independently using local information. Hence, ED-MAC can guarantee conflict-free transmissions and receptions of data packets. Compared with other conflict-free MAC protocols, ED-MAC is distributed and more reliable, i.e., it schedules according to the priority of sensor nodes which based on their depth in the network. We then evaluate design choices and protocol performance through extensive simulation to study the load effects and network scalability in each protocol. The results show that ED-MAC outperforms the contention-based MAC protocols and achieves a significant improvement in terms of successful delivery ratio, throughput, energy consumption, and fairness under varying offered traffic and number of nodes
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