Developing an adaptive 3-dimensional (3D) topology control algorithm is important because most wireless nodes are mobile and deployed in buildings. Moreover, in buildings, wireless link qualities and topologies change frequently due to various objects and the interference from other wireless devices. Previous topology control algorithms can suffer significant performance degradation because they only use the Euclidean distance for the topology construction. In this paper, we propose a novel adaptive 3D topology control algorithm for wireless ad-hoc sensor networks, especially in indoor environments. The proposed algorithm adjusts the minimum transmit power adaptively with considering the interference effect. To construct the local topology, each node divides the 3D space, a sphere centered at itself, into k equal cones by using Platonic solid (i.e., regular k-hedron) and selects the neighbor that requires the lowest transmit power in each cone. Since the minimum transmit power values depend on the effect of interferences, the proposed algorithm can adjust topology adaptively and preserve the network connectivity reliably. To evaluate the performance of algorithms, we conduct various experiments with simulator and real wireless platforms. The experimental results show that the proposed algorithm is superior to the previous algorithms in terms of the packet delivery ratio and the energy consumption with relatively low complexity.

Maintaining the lowest possible transmission power in the wireless sensor networks (WSNs) is vulnerable to the interference fluctuations because of the bad signal-to-interference-plus-noise-ratio (SINR). The previous transmission power control (TPC) algorithms do not consider much for the interferences from other 2.4 GHz devices, which can cause significant performance degradations in real world deployments. This paper proposes the interference-aware transmission power control (I-TPC) algorithm for WSNs. In the proposed algorithm, each node dynamically adjusts the transmission power and the received signal strength (RSS) target, hence the appropriate SINR is provided even when the wireless LAN (WLAN) interferences become strong. The experimental results show that the proposed algorithm outperforms the previous algorithms in terms of the energy and the packet reception ratio (PRR) performance in WLAN interference environments.

The IEEE 802.15.4a standard enables geographical routing in ZigBee networks but previous geographical routing algorithms can suffer high packet loss due to the interference effects. This letter proposes an interference-aware energy-efficient geographical routing algorithm for the IEEE 802.15.4a networks. The proposed algorithm estimates the energy cost by considering the interference effects and forwards a packet to the neighbor with the lowest energy cost to advance. Experimental results show that the proposed algorithm outperforms the previous algorithms in terms of the delivery ratio and the energy consumption.

IEEE 802.15.4a standard enables location-aided routing or topology control in ZigBee networks, since it uses time-of-arrival (TOA)-based ranging technique. However, TOA based techniques may yield location error due to the non-line-of-sight (NLOS) effects, and hence degrade the network performance. In this letter, we demonstrate the impact of NLOS on the localization performance and propose a location error detection and compensation algorithm for IEEE 802.15.4a networks. The proposed algorithm detects NLOS by using the min-max algorithm and compensates the location error by using the Kalman filter. Experimental results show that the proposed algorithm significantly reduces the localization errors in indoor environments.