Gathering Data with PacketinPacket in Wireless Sensor Networks Abstract   In many wireless sensor network (WSN) missioncritical applications, a collector, e.g., a drone acting as a data sink, is required to gather data from all the source nodes in the area of interest. It is, thus, an alltoone scenario. Data from each node (e.g., local temperature or its binary status) normally only consists of several bytes. Furthermore, often, data collection is expected to be done as fast as possible, especially for missioncritical applications or applications where a batterypowered sink is used (e.g., a drone). Thus, it is preferred that there is no preparation phase for the network to schedule or establish any routes in advance. Concurrent transmission (CT), a novel communication paradigm, has been shown to effectively achieve reliable and energyefficient flooding in lowpower wireless networks. With multiple nodes exploiting a receiveandforward scheme, this technique requires no routing and works effectively in floodingbased networks, i.e., in onetomany scenarios. Hence, CTbased communication is a good choice for fast data collection. However, a kind of global scheduling is essential for data collection in CTbased WSNs, in order to globally schedule a node that initiates a flooding in the network. In this article, to comply with the requirements of the aforementioned data collection application, we propose PacketinPacket (PiP), an energyefficient paradigm requiring no global scheduling for timely data collection in lowpower WSNs. PiP builds on concurrent transmissions and uses a packet concatenation capability to gather singlehop information in a besteffort manner. PiP does not require any prescheduling of traffic in the network, and thereby significantly reducing collection time. We compare PiP with a number of stateoftheart protocols by extensive experiments in two testbeds, FlockLab and Indriya, respectively. Experimental results show that PiP achieves high reliability and low latency in all the scenarios in the realworld testbeds. Specifically, when the transmission power of nodes is set to 0 dBm, PiP takes only 287 ms (at least 1.8xe2x80xafxc3x97xe2x80xaf faster than the stateoftheart protocols) to complete a 26toone data collection in FlockLab and 965 ms (1.1xe2x80xafxc3x97xe2x80xaf faster than a stateoftheart protocol LWB) to complete a 42toone collection in Indriya, respectively.

ZBP: A ZoneBased Broadcasting Protocol for Wireless Sensor Networks Wireless Sensor Networks (WSNs) have been widely used in motoring and collecting interests of environment information. Packet flooding or broadcasting is an essential function for establishing a communication path from sink node to a region of sensor nodes. However, flooding operation consumes power and bandwidth resources and raises the packet collision and contention problems, which reduce the success rate of packet transmissions and consume energy. This article proposes an efficient broadcasting protocol to reduce the number of sensor nodes that forward the query request, hence improves the packet delivery rate and saves bandwidth and power consumptions. Sensor node that received the query request will dynamically transfers the coordinate system according to the zoneID of source node and determines whether it would forward the request or not in a distributed manner. Compared with the CBM and traditional flooding operation, experimental results show that the proposed zonebased broadcasting protocol decreases the bandwidth and power consumptions, reduces the packet collisions, and achieves high success rate of packet broadcasting.