This paper considers the use of an antenna selection mechanism to reduce the cost of multiple analog transmit/receive chains in multiple-input multiple-output (MIMO) systems. With the optimal antenna selection scheme, radio-frequency chains can optimally connect with the best subset of transmitter and/or receiver antennas. However, the optimal antenna selection algorithm requires an exhaustive search of all possible combinations to find the optimum subset at the transmitter and/or receiver, thus resulting in high complexity. In order to reduce the computational load while still maximizing channel capacity, we introduce the simulated annealing (SA) method, an effective algorithm that solves various combinatorial optimization problems, to search the optimal subset. The simulation results show that the performance of the proposed SA method provides almost the same channel capacity as that of the optimal exhaustive search algorithm while maintaining low complexity.

Performance of band-limited baseband synchronous CDMA using orthogonal Independent Component Analysis (ICA) spreading sequences is investigated. The orthogonal ICA sequences have an orthogonality condition in a synchronous CDMA like the Walsh-Hadamard sequences. Furthermore, these have useful correlation properties like the Gold sequences. These sequences are obtained easily by using the ICA which is one of the brain-style signal processing algorithms. In this study, the ICA is used not as a separator for received signal but as a generator of spreading sequences. The performance of the band-limited synchronous CDMA using the orthogonal ICA sequences is compared with the one using the Walsh-Hadamard sequences. For limiting bandwidth, a Root Raised Cosine filter (RRC) is used. We investigate means and variances of correlation outputs after passing the RRC filter and the Bit Error Rates (BERs) of the system in additive white Gaussian noise channel by numerical simulations. It is found that the BER in the band-limited system using the orthogonal ICA sequences is much lower than the one using the Walsh-Hadamard sequences statistically.

In the nanometer era, the power integrity problem has become one of the critical issues. Although checking this problem earlier can speed up the analysis, not so many tools are available now due to the limited design information at high levels. Most existing approaches at gate level require extra information of the cell library, which may require extra characterization efforts while migrating to new cell libraries. Therefore, an analytical approach is proposed in this paper to dynamically estimate the supply current waveforms at gate level using existing library information only, even for sequential circuits. The experimental results have shown that the estimation errors of such a quick approach are only 10% compared to HSPICE results.

Many learning machines that have hierarchical structure or hidden variables are now being used in information science, artificial intelligence, and bioinformatics. However, several learning machines used in such fields are not regular but singular statistical models, hence their generalization performance is still left unknown. To overcome these problems, in the previous papers, we proved new equations in statistical learning, by which we can estimate the Bayes generalization loss from the Bayes training loss and the functional variance, on the condition that the true distribution is a singularity contained in a learning machine. In this paper, we prove that the same equations hold even if a true distribution is not contained in a parametric model. Also we prove that, the proposed equations in a regular case are asymptotically equivalent to the Takeuchi information criterion. Therefore, the proposed equations are always applicable without any condition on the unknown true distribution.

This position paper outlines the author's view on architectural directions and key technology enablers for the future mobile Internet. It is pointed out that mobile and wireless services will dominate Internet usage in the near future, and it is therefore important to design next-generation network protocols with features suitable for efficiently serving emerging wireless scenarios and applications. Several key requirements for mobile/wireless scenarios are identified - these include new capabilities such as dynamic spectrum coordination, cross-layer support, disconnection tolerant routing, content addressing, and location awareness. Specific examples of enabling technologies which address some of these requirements are given from ongoing research projects at WINLAB. Topics covered briefly include wireless network virtualization, the cache-and-forward (CNF) protocol, geographic (GEO) protocol stack, cognitive radio protocols, and open networking testbeds.

The National Institute of Information and Communications Technology (NICT) vision and five network targets of research and development (R&D) of the NeW-Generation Network (NWGN) are presented in this letter. The NWGN is based on new design concepts that look beyond the next generation network (NGN). The NWGN will maintain the sustainability of our prosperous civilization and help resolve various social issues and problems by using information and communication technologies (ICTs). NICT's vision for NWGN is also presented in this letter. Based on this vision, 19 items concerning social issues and future social outlook are analyzed, and the functional requirements of the NWGN are extracted. The requirements are refined and categorized into five network targets that must be developed for realizing the vision.

In this letter we propose a novel resource allocation and admission control strategy for OFDMA-based emerging LTE systems. Considering users' reneging and migration between service providers, we first prove that the optimal resource allocation problem, which maximizes the service provider's gross income is, NP-complete. Subsequently, we propose two different heuristics based on dynamic programming and greedy algorithms to get a near-optimal resource allocation and admission control strategy in computationally feasible time. Simulation results point out that the solutions offer increased gross income of the service provider, while offering low latency, adequate throughput and session acceptance.

The first global interoperability experiment of GMPLS controlled Ethernet with VLAN tag swapping between two different implementations is successfully demonstrated. High definition video streaming is realized through a newly established Layer 2 Label Switched Path (L2-LSP). The results of this experiment can be applied to designing reliable Layer 2 networks.

An improved soft-input soft-output (SISO) minimum mean-squared error (MMSE) detection method is proposed for joint coding and precoding OFDM systems under imperfect channel estimation. Compared with the traditional mismatched detection which uses the channel estimate as its exact value, the signal model of the proposed detector is more accurate and the influence of channel estimation error (CEE) can be effectively mitigated. Simulations indicate that the proposed scheme can improve the bit error rate (BER) performance with fewer pilot symbols.

We consider a single-link multi-source network with FAST TCP sources. We adopt a continuous-time dynamic model for FAST TCP sources, and propose a static model to adequately describe the queuing delay dynamics at the link. The proposed model turns out to have a structure that reveals the time-varying network feedback delay, which allows us to analyze FAST TCP with due consideration of the time-varying network feedback delay. Based on the proposed model, we establish sufficient conditions for the boundedness of congestion window of each source and for the global asymptotic stability. The asymptotic stability condition shows that the stability property of each source is affected by all other sources sharing the link. Simulation results illustrate the validity of the sufficient condition for the global asymptotic stability.

Trusted Network Connect provides the functionality of the platform authentication and integrity verification which is crucial for enhancing the security of authentication protocols. However, applying this functionality directly to concrete authentications is susceptible to unknown attacks and efficiency degradation. In this paper, we propose TWMAP, a novel authentication protocol for WLAN Mesh networks in a trusted environment which completed the platform authentication and integrity verification during the user authentication. And, the Schnorr asymmetric signature scheme is utilized to reduce the overhead of the client. The security properties of the new protocol are examined using the Universally Composable Security model. The analytic comparisons and simulation results show that the new protocol is very efficient in both computing and communication costs.

This paper proposes a sensing system for a behavior detection system using an ultrasonic oscillosensor and an air pressure sensor. The ultrasonic oscillosensor sensor has a cylindrical tank filled with water. It detects the vibration of the target object from the signal reflected from the water surface. This sensor can detect a biological vibration by setting to the bottom bed frame. The air pressure sensor consists of a polypropylene sheet and an air pressure sensor, and detects the pressure information by setting under the bed's mattress. An increase (decrease) in the load placed on the bed is detected by the increase (decrease) in the pressure of the air held in the tube attached to the sheet. We propose a behavior detection system using both sensors, complementally. The system recognizes three states (nobody in bed, keeping quiet in bed, moving in bed) using both sensors, and we detect the behavior before getting out of bed by recognized these states. Fuzzy logic plays a primary role in the system. As the fundamental experiment, we applied the system to five healthy volunteers, the system successfully recognized three states, and detected the behavior before getting out of bed. As the clinical experiment, we applied the system to four elderly patients with dementia, the system exactly detected the behavior before getting out of the bed with enough time for medical care support.

This paper evaluates impact of self-heating in wire interconnection on signal propagation delay in an upcoming 32 nm process technology, using practical physical parameters. This paper examines a 64-bit data transmission model as one of the most heating cases. Experimental results show that the maximum wire temperature increase due to the self-heating appears in the case where the ratio of interconnect delay becomes largest compared to the driver delay. However, even in the most significant case which induces the maximum temperature rise of 11.0, the corresponding increase in the wire resistance is 1.99% and the resulting delay increase is only 1.15%, as for the assumed 32 nm process. A part of the impact reduction of wire self-heating on timing comes from the size-effect of nano-scale wires.

Two essential technologies for a 3D Solid State Drive (3D-SSD) with a boost converter are presented in this paper. The first topic is the spiral inductor design which determines the performance of the boost converter, and the second is the effect of TSV's on the boost converter. These techniques are very important in achieving a 3D-SSD with a boost converter. In the design of the inductor, the on-board inductor from 250 nH to 320 nH is the best design feature that meets all requirements, including high output voltage above 20 V, fast rise time, low energy consumption, and area smaller than 25 mm2. The use of a boost converter with the proposed inductor leads to a reduction of the energy consumption during the write operation of the proposed 1.8-V 3D-SSD by 68% compared with the conventional 3.3-V 3D-SSD with the charge pump. The feasibility of 3D-SSD's with Through Silicon Vias (TSV's) connections is also discussed. In order to maintain the advantages of the boost converter over the charge pump, the reduction of the parasitic resistance of TSV's is very important.

This paper investigates whether the self-heating effect in short intra-block wires will become apparent with technology scaling. These wires seem to have good thermal radiation characteristics, but we validate that the self-heating effect in local signal wires will be greater than that in optimal repeater-inserted global wires. Our numerical experiment shows that the maximum temperature increase from the silicon junction temperature will reach 40.4 in a steady state at a 14-nm process. Our attribution analysis also demonstrates that miniaturizing the area of wire cross-section exacerbates self-heating as well as using low-κ material and increased power dissipation in advanced technologies below 28 nm. It is revealed that the impact of self-heating on performance in local wires is limited, while underestimating the temperature may cause an unexpected reliability failure.

This paper presents a Time Difference Amplifier (TDA) that amplifies the input time difference into the output time difference. Cross coupled chains of variable delay cells with the same number of stages are applicable for TDA, and the gain is adjusted via the closed-loop control. The TDA was fabricated using 65 nm CMOS and the measurement results show that the time difference gain is 4.78 at a nominal power supply while the designed gain is 4.0. The gain is stable enough to be less than 1.4% gain shift under 10% power supply voltage fluctuation.

The current Internet is not capable of meeting the future communication requirements of society, i.e., reliable connectivity in a ubiquitous networking environment. The shortcomings of the Internet are due to the lack of support for mobility, multihoming, security and heterogeneous network layer protocols in the original design. Therefore, to provide ubiquitous networking facilities to the society for future innovation, we have to redesign the future Internet, which we call the New Generation Network. In this paper, we present the Heterogeneity Inclusion and Mobility Adaptation through Locator ID Separation (HIMALIS) architecture for the New Generation Network. The HIMALIS architecture includes a new naming scheme for generating host names and IDs. It also includes a logical control network to store and distribute bindings between host names, IDs, locators and other information useful for providing support for network operation and control. The architecture uses such information to manage network dynamism (i.e., mobility, multihoming) and heterogeneity in network layer protocols. We verify the basic functions of the architecture by implementing and testing them using a testbed system.

A RFID group scanning protocol enables a RFID reader to produce a proof of co-existence of multiple RFID tags. This type of protocol is also referred to as yoking-proof, grouping-proof and co-existence proof. In this letter, we show that all of the previous group scanning protocols are vulnerable to relay attack.

The Hough transform is known to be an effective technique for target detection and track initiation in search radars. However, most papers have focused on the simplistic applications of this technique which consider a 2-D data space for the Hough transform. In this paper, a new method based on xthe Hough transform is introduced for detecting targets in a 3-D data space. The data space is constructed from returned surveillance radar signal using the range and bearing information of several successive scans. This information is mapped into a 3-D x-y-t Cartesian data space. Targets are modeled with four parameters in this data space. The proposed 3-D Hough detector is then used to detect the existent targets in the 3-D surveillance space by mapping the returned signal of the radar from the data space to the parameter space. This detector, which is constructed of two detection stages, integrates the returned data of each target non-coherently along its 3-D trajectory in one parameter space cell related to this target. Hence, the detection performance will improve. The effectiveness of the new 3-D Hough detector is demonstrated through deriving the detection statistics analytically and comparing the results with those of several comprehensive simulations. The performance improvement of this detector is shown by comparing its detection range with the conventional detector. The proposed detector is also evaluated with real radar data and its efficiency is confirmed.

A boosted bit line program scheme is proposed for low operating voltage in the multi-level-cell (MLC) NAND flash memory. Our BL to BL boosting scheme, which uses the BL coupling capacitance, is applied to achieve a higher channel potential than is possible with Vcc, so that the Vpass window margin is improved by up to 59% in 40 nm MLC NAND flash memory with 2.7 V Vcc. In the case of 1.8 V Vcc, the margin of the proposed scheme is 12% higher than one of the conventional schemes at 2.7 V Vcc.