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A method for detecting human motion in complex scenarios based on Channel State Information (CSI) is presented. First, the sensitivity of CSI phase information to human motion is explored, especially to the strenuous motion. Through a large number of experiments, the influence of human motion on CSI phase is found out, and the characteristics of signal changes are extracted. The One-class Support...
WiFi signals based applications, such as indoor localization, human activity recognition and trace tracking, have been increasing attention in the past decade. WiFi signals are sensitive to the change of indoor environment, so the above mentioned applications encounter challenges which contain dynamic indoor environment, device diversity and motion influence. We mainly survey techniques of motion...
In recent years, issues of Wireless Sensor Networks (WSNs) have been widely studied. The energy is limited in WSNs. However, it always takes much energy to achieve highly accurate time synchronization. In this paper, a Spanning Tree-based Energy-efficient Time Synchronization (STETS) strategy for WSNs is proposed. In STETS, only a small number of sensor nodes in the WSN have the privilege to send...
In wireless body sensor networks (WBSN) and wireless body area networks (WBAN), sensor nodes have different bandwidth requirements, therefore, heterogeneous traffic is created. In this paper, we propose a statistical medium access control (MAC) protocol with periodic synchronization for use in heterogeneous traffic networks based on human body communication (HBC). The MAC protocol is designated to...
The design and analysis of routing algorithm is an important issue in Wireless Sensor Networks (WSNs). Most traditional geographical routing algorithms cannot achieve good performance in duty-cycled networks. In this paper, we propose a k-connected overlapping clustering approach with energy awareness, namely k-OCHE, for routing in WSNs. The basic idea of this approach is to select a cluster head...
Trend of accelerated aging society increases need of care for the aged at home. To fit this need, we designed the continuous body posture monitoring system based on wireless sensor networks. The hardware platform is made up of anchor nodes, the central control node and wireless sensor nodes which include the three axis low-g accelerometer MMA7260, 2-axis magnetic sensor HMC5883L and CC2431 System-on-Chip...
This paper introduces the characteristics of the wireless network, including self-organizing, dynamic topology, wireless communications and so on, which make the network nodes have limited energy, the same as processing power, storage capacity and communication capabilities, therefore, the efficient use of energy, maximizing its network cycle is the wireless sensor network's core issue. Network coding...
Congestion has always been a serious problem for all kinds of communication networks. Wireless sensor networks (WSN) face special difficulties in dealing with congestion due to their unique requirements and constraints. Various congestion control schemes for WSN have been proposed recently. These schemes try to solve the problem either at the MAC layer or through a cross-layer approach. This paper...
Node localization plays a key role in the validity of WSN applications. To improve the precision of WSN node localization, A localization algorithm is studied which is based on Maximum Likelihood Estimation (MLE). A new RSSI ranging model is proposed that is depicted by two empirical models. The optimal number of reference WSN nodes for localization are studied. The test results show that the error...
This paper focuses on studying the impacts of a duty-cycle based CKN sleep scheduling algorithm for our previous designed TPGF geographical multipath routing algorithm in wireless sensor networks (WSNs). It reveals the fact that waking up more sensor nodes cannot always help to improve the exploration results of TPGF in a duty-cycle based WSN. Furthermore, this study provides the meaningful direction...
This paper introduces an intelligent remote monitor system based on ZigBee sensor networks for IDC (Internet Data Center) room. The system consists of two parts: three types of ZigBee modules and the server module. The three types of ZigBee modules contain first-cluster node, second-cluster node and sensor end-node. The system can control remote IDC room based on the connection of the ZigBee protocols...
Based on free probability theory, a new scheme for frequency band sensing of spreading communication system is proposed. Unlike previous studies in the field, the new scheme does not require the knowledge of the spreading sequences of users and is related to the asymptotic free behavior of random matrices. Simulation result shows that the convergence characteristic holds true even for a small number...
This paper reports a low power transceiver designed for wearable medical healthcare system. Based on a novel energy-efficient wideband wireless communication scheme that uses human body as a transmission medium, the transceiver can achieve a maximum 15 Mbps data rate with total receiver sensitivity of -30 dBm. The chip measures only 0.56 mm2 and was fabricated in the SMIC 0.18 um 1P6M RF CMOS process...
With the ubiquitous application of Internet and wireless networks, H.264 video communication becomes more and more popular. However, due to the high-efficiently predictive coding and the variable length entropy coding, it is more sensitive to transmission errors. Error concealment (EC) is just an approach to utilize the spatial and temporal correlations to conceal the corrupted region. In this paper,...
Wireless sensor network (WSN) consists of a group of sensors or nodes, linked by a wireless medium (infrared or radio frequency) to perform distributed sensing tasks. The dynamic and lossy nature of wireless communication poses major challenges for highly dense WSN. In our previous work, we proposed a new networking topology, the Cayley pseudo-random protocol (Arden, 1991) (Noel, 2006) for large wireless...
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