SUMMARY"Internet of Things" (IoT) requires information to be collected from "anything", "anytime", and "anywhere". In order to achieve this, wireless devices are required that have (1) automatic data acquisition capability, (2) small size, (3) long life, and (4) long range communication capability. One way to meet these requirements is to adopt active Radio Frequency Identification (RFID) systems. Active RFID is more advantageous than passive RFID and enables higher data reading performance over longer distances. This paper surveys active RFID systems, the services they currently promise to provide, technical problems common to these services, and the direction in which research should head in the future. It also reports the results of EPCglobal (EPC: Electronic Product Code) pilot tests conducted on global logistics for tracking ocean/air container transportation using active RFID systems for which we developed several new types of active RFID tags. The test results confirm that our active RFID tags have sufficient capability and low power consumption to well support ocean/air transportation and logistics service.
We are developing optical layer-2 switch network that achieves dynamic path bandwidth allocation (DPBA) for efficient aggregation in metro NWs. We show the experimental results of DPBA cycle according to variations in traffic on NW scale of 1000x10.
IntroductionNetwork (NW) traffic is increasing exponentially, and it is therefore becoming increasingly necessary to develop cost-effective NWs in terms of equipment cost and power consumption. For this trend, we are developing an optical layer-2 switch network 1 (OL2SW-NW) that can efficiently aggregate traffic in a largescale metro NW. The OL2SW-NW is based on a WDM/TDM ring NW of L WDM channels. This allows the bandwidth of wavelengths in the NW to be shared with the ground paths between 1000 aggregation switches (SWs) on the access NW and 10 IP routers (RRs) on the core NW. The OL2SW-NW enables NW bandwidth to be shared effectively as a TDM-PON 2 does by allocating timeslots (TSs) to each ground path and performing ADD/DROP of data according to allocated TSs (Fig. 1). The OL2SW-NW can dynamically change each bandwidth of ground path by changing the number of allocated TSs according to the amount of traffic on each ground path at every fixed time. To achieve the bandwidth allocation, traffic information on all ground paths is collected at a central TS scheduler (SCH) for TS allocation (TSA). Hence, collecting traffic information from all ground paths and TSA processing at the SCH will produce bottlenecks in large-scale NWs. In this paper, we show the experimental results of dynamic path bandwidth allocation (DPBA) in 1000x10-scale NW by using a novel TSA algorism and TS converters (TSCs).
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