Superframe Duration Allocation Schemes to Improve the Throughput of Cluster-Tree Wireless Sensor Networks

Abstract

Abstract:The use of Wireless Sensor Network (WSN) technologies is an attractive option to support wide-scale monitoring applications, such as the ones that can be found in precision agriculture, environmental monitoring and industrial automation. The IEEE 802.15.4/ZigBee cluster-tree topology is a suitable topology to build wide-scale WSNs. Despite some of its known advantages, including timing synchronisation and duty-cycle operation, cluster-tree networks may suffer from severe network congestion problems due to the convergecast pattern of its communication traffic. Therefore, the careful adjustment of transmission opportunities (superframe durations) allocated to the cluster-heads is an important research issue. This paper proposes a set of proportional Superframe Duration Allocation (SDA) schemes, based on well-defined protocol and timing models, and on the message load imposed by child nodes (Load-SDA scheme), or by number of descendant nodes (Nodes-SDA scheme) of each cluster-head. The underlying reasoning is to adequately allocate transmission opportunities (superframe durations) and parametrize buffer sizes, in order to improve the network throughput and avoid typical problems, such as: network congestion, high end-to-end communication delays and discarded messages due to buffer overflows. Simulation assessments show how proposed allocation schemes may clearly improve the operation of wide-scale cluster-tree networks.

Mecanismo Eficiente para Disseminação do Tráfego de Controle em Redes de Sensores Sem Fio Cluster-Tree baseadas no IEEE 802.15.4

“…O conjunto de CHs da rede cluster-tree é caracterizado por: CH i = (SD i , BI i ), 1 ≤ i ≤ n CH ; onde SD i e BI i correspondem à duração de superframe e ao intervalo de beacons para o cluster-head CH i , respectivamente. Além disso, é assumido que todos os cluster-heads possuem o mesmo BI e as durações de superframes para os CHs são definidas considerando o esquema de alocação proposto em [17].…”

“…CT-SIM é baseado no Castalia [22], um simulador de eventos discretos open-source para RSSFs e redes embarcadas gerais, desenvolvido pela National ICT Australia (NICTA) e baseado na plataforma OMNeT++. A rede cluster-tree considera o esquema SDA (Superframe Duration Allocation) [17] para atribuir valores de Duração de Superframe (SD) e Intervalo de Beacons (BI), onde os valores para SDs são proporcionalmente alocados para cada CH de acordo com o número de nós descendentes. Com relação ao processo de formação da rede cluster-tree, cada CH pode associar no máximo 6 nós filhos, o que implica que, à medida que o número de nós aumenta (diferentes cenários), a profundidade e o número de clusters também aumentam.…”

A Survey on Real-Time Communications in Wireless Sensor Networks

“…In this aspect, cross-layered architecture and approach are another promising research area to improve the performance. Related to this issue, it is worth mentioning that superframe duration allocation schemes for cluster-heads lead to improvement throughput for cluster-tree [91]. Through the proposed allocation scheme, network congestion around the PAN coordinator, high message communication delays, and a high number of discarded messages due to buffer overflows are significantly reduced.…”

Alternative Path Communication in Wide-Scale Cluster-Tree Wireless Sensor Networks Using Inactive Periods

“…The network is composed of N coordinator nodes (including the PAN coordinator), that act as Cluster-Heads ( CHs ) of their clusters and periodically send beacon frames to synchronise their child nodes, such that:$C{H}_i=(S{D}_i,B{I}_i),1\le i\le N,$ where i is a unique identifier for the specific cluster, $S{D}_i$ corresponds to the Superframe Duration and $B{I}_i$ is the Beacon Interval of the cluster-head $C{H}_i$. We assume that values for BO and SO are defined according to the load supported by each of the branches of the cluster-tree, considering a superframe duration allocation approach, as the one proposed by [59]. We also assume that the cluster’s active periods were previously scheduled, considering a classical time division superframe scheduling approach, as the one proposed by [7].…”