The hidden-node problem has been shown to be a majorsource of Quality-of-Service (QoS) degradation in WirelessSensor Networks (WSNs) due to factors such as the limitedcommunication range of sensor nodes, link asymmetry and thecharacteristics of the physical environment. In wirelesscontention-based Medium Access Control protocols, if twonodes that are not visible to each other transmit to a thirdnode that is visible to the formers, there will be a collision –usually called hidden-node or blind collision. This problemgreatly affects network throughput, energy-efficiency andmessage transfer delays, which might be particularlydramatic in large-scale WSNs. This paper tackles the hiddennodeproblem in WSNs and proposes H-NAMe, a simple yetefficient distributed mechanism to overcome it. H-NAMerelies on a grouping strategy that splits each cluster of a WSNinto disjoint groups of non-hidden nodes and then scales tomultiple clusters via a cluster grouping strategy thatguarantees no transmission interference between overlappingclusters. We also show that the H-NAMe mechanism can beeasily applied to the IEEE 802.15.4/ZigBee protocols withonly minor add-ons and ensuring backward compatibilitywith the standard specifications. We demonstrate thefeasibility of H-NAMe via an experimental test-bed, showingthat it increases network throughput and transmission successprobability up to twice the values obtained without H-NAMe.We believe that the results in this paper will be quite useful inefficiently enabling IEEE 802.15.4/ZigBee as a WSN protocol
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