We design a silicon gate-all-around junctionless field-effect transistor (JLFET) using a step thickness gate oxide (GOX) by the Sentaurus technology computer-aided design simulation. We demonstrate the different gate-induced drain leakage (GIDL) mechanism of the traditional inversion-mode field-effect transistor (IMFET) and JLFET. The off leakage in the IMFET is dominated by the parasitic bipolar junction transistor effect, whereas in the JLFET it is a result of the volume conduction due to the screening effect of the accumulated holes. With the introduction of a 4 nm thick-second GOX and remaining first GOX thickness of 1 nm, the tunneling generation is reduced at the channel-drain interface, leading to a decrease in the off current of the JLFET. A thicker second GOX has the total gate capacitance of JLFETs, where a 0.3 ps improved intrinsic delay is achieved. This alleviates the capacitive load of the transistor in the circuit applications. Finally, the short-channel effects of the step thickness GOX JLFET were investigated with a total gate length from 40 nm to 6 nm. The results indicate that the step thickness GOX JLFETs perform better on the on/off ratio and drain-induced barrier lowering but exhibit a small degradation on the subthreshold swing and threshold roll-off.

In this paper, we explore how to enhance the physical layer security performance in downlink cellular networks through cooperative jamming technology. Idle user equipments (UE) are used to cooperatively transmit jamming signal to confuse eavesdroppers (Eve). We propose a threshold-based jammer selection scheme to decide which idle UE should participate in the transmission of jamming signal. Threshold conditions are carefully designed to decrease interference to legitimate channel, while maintain the interference to the Eves. Moreover, fewer UE are activated, which is helpful for saving energy consumptions of cooperative UEs. Analytical expressions of the connection and secrecy performances are derived, which are validated through Monte Carlo simulations. Theoretical and simulation results reveal that our proposed scheme can improve connection performance, while approaches the secrecy performance of [12]. Furthermore, only 43% idle UEs of [12] are used for cooperative jamming, which helps to decrease energy consumption of network.

By exploiting the inherent sparsity of wireless propagation channels, the theory of compressive sensing (CS) provides us with novel technologies to estimate the channel state information (CSI) that require considerably fewer samples than traditional pilot-aided estimation methods. In this paper, we describe the block-sparse structure of the fast time-varying channel and apply the model-based CS (MCS) for channel estimation in orthogonal frequency division multiplexing (OFDM) systems. By exploiting the structured sparsity, the proposed MCS-based method can further compress the channel information, thereby allowing a more efficient and precise estimation of the CSI compared with conventional CS-based approaches. Furthermore, a specific pilot arrangement is tailored for the proposed estimation scheme. This so-called random grouped pilot pattern can not only effectively protect the measurements from the inter-carrier interference (ICI) caused by Doppler spreading but can also enable the measurement matrix to meet the conditions required for MCS with relatively high probability. Simulation results demonstrate that our method has good performance at high Doppler frequencies.

We propose the asynchronous receiver-initiated MAC protocol with the stair-like sleep mode; each node reduces its own sleep time by the sleep-change-rate depending on the number of hops from the source to the sink in wireless sensor networks (WSNs). Using the stair-like sleep approach, our protocol achieves high delivery ratio, low packet delay, and high energy efficiency due to the reduction in idle listening time. Our protocol can formulate the upper bound of the idle listening time because of the feature that the sleep time decreases in a geometric progression, and the reduction of the idle listening time is obtained by using the stair-like sleep approach. In our proposed scheme, the sink calculates the sleep change rate based on the number of hops from the source to the sink. By using the control packets which have the role of the acknowledgment (ACK), our proposed protocol can achieve the stair-like sleep with no additional control packets. In addition, even in the network condition that multi-targets are detected, and the number of hops to the sink are changed frequently, our proposed protocol can change the sleep change rate adaptively because the sink can always obtain the number of hops from the source to the sink. Simulation results show that the proposed protocol can improve the performance in terms of the packet delivery ratio, the packet delay, and the energy efficiency compared to the conventional receiver-initiated MAC (RI-MAC) protocol.

The IEEE 802.16e standard specifies the sleep mode and the idle mode of a mobile station (MS) for power saving. In this paper, to reduce the energy consumption of the MS, we employ the sleep mode while the MS is on-session, and the idle mode while it is off-session. Under the assumption that the time duration from the end of a session to the arrival of a new downlink session request follows an exponential distribution of the mean and that arrivals of messages during an on-session follow a Poisson process with rate λ, we analyze the awake mode period and the sleep mode period by using the busy period analysis of the M/G/1 queue, and then we derive the total mean length of an on-session which consists of a geometric number of awake mode periods and sleep mode periods. Since the sum of an on-session and an off-session constitutes a cycle, we can express the average power consumption in terms of the mean lengths of an awake mode period, a sleep mode period and an idle mode period. The average power consumption indicates how much the MS can save energy by employing the sleep mode and the idle mode. We also derive the Laplace Stieltjes transform (and the mean) of the queueing delay of messages to examine a tradeoff between the power consumption and the delay of messages. Analytical results, which are shown to be well-matched by simulations, address that our employment of the sleep mode and the idle mode provides a considerable reduction in the energy consumption of the MS.

This study describes the dependence of the surface electric field to the junction depth of source/drain-extension, and the suppression of gate induced drain leakage (GIDL) in fully depleted shallow junction gate-overlapped source/drain-extension (SDE). The GIDL can be reduced by reducing shallow junction depth of drain-extension. Total space charges are a function of junction depth in fully depleted shallow junction drain-extension, and the surface potential is proportional to these charges. Because the GIDL is proportional to surface potential, GIDL is the function of junction depth in fully depleted shallow junction drain-extension. Therefore, the GIDL is suppressed in a fully depleted shallow junction drain-extension by reducing surface potential. Negative substrate bias and halo doping could suppress the GIDL, too. The GIDL characteristic under negative substrate bias is contrary to other GIDL models.

Practical design of double-gate undoped-channel FinFET has been investigated through 3D device simulations considering gate-induced drain leakage (GIDL). Optimization of FinFET structure including source/drain (S/D) profile was carried out for hp45 low standby power (LSTP) device whose gate length (Lg) is equal to 25 nm. GIDL is reduced by using gradual and offset S/D profile while degradation of drive current is minimized. Through the optimization of lateral straggle and offset of S/D profile, the ITRS specifications for drive current and off-state leakage current are achievable by FinFET with 10 nm fin width.

We present measurements of Gate-Induced-Drain-Leak-age at various temperatures and terminal biases. Besides Band-to-Band tunneling leakage observed at high Drain-to-Gate voltage VDG, we also observed Trap-Assisted-Tunneling leakage current at lower VDG. Based on ISE TCAD simulations of the electric field, we propose analytical models for Band-to-Band and Trap-Assisted Gate-Induced-Drain-Leakage currents suitable for compact modeling.

Up to now, a lot of efforts have been made for the management of telecommunication networks and equipment, but less effort has been made for the realization of higher-layer service and business management. Common Object Request Broker Architecture (CORBA) provides the infrastructure for interoperability of various object-oriented management applications in a distributed environment, and being widely used to develop distributed systems in many areas of information processing technologies. There are recently worldwide growing interests for applying CORBA technology for the realization of higher layer Telecommunication Management Network (TMN) management functions. In this paper, we propose a platform architecture for the efficient integration of CORBA technology within TMN framework, where CORBA-based management functions as well as TMN-based management functions can be realized efficiently. GDMO/ASN. 1 to IDL translator has been designed and implemented for translating TMN management information into OMG CORBA IDL interface. The CORBA/CMIP gateway has also been designed for realization of the interaction translation specification of JIDM task force with some additional extensions. Finally, we evaluate the performance of the CORBA-based network management system, and analyze the code reusability for the construction of the CORBA-based management system, in order to show the efficiency of the architecture.

The Yasuura method is effective for calculating scattering problems by bodies of revolution. However dealing with 3-D scattering problems, we need to solve bigger size dense matrix equations. One of the methods to solve 3-D scattering is to use multipole expansion which accelerate the convergence rate of solutions on the Yasuura method. We introduce arrays of multipoles and obtain rapidly converging solutions. Therefore we can calculate scattering properties over a relatively wide frequency range and clarify scattering properties such as frequency dependence, shape dependence, and polarization dependence of 3-D scattering from perfectly conducting scatterer. In these numerical results, we keep at least 2 significant figures.