In recent years, the enormous energy consumption of wireless communication systems has aroused universal concerns throughout world. Hence, efficiency become one central topics in today's industry. this paper, we study energy-efficient resource allocation for Long Term Evolution (LTE) cellular mobile systems. To be applicable LTE systems, both multiple-input multiple-output (MIMO) orthogonal frequency-division multiple access (OFDMA) radio network and blocks (RBs) subchannel assignment are...

In this letter, the energy-efficient radio resource scheduling is studied with quality of service (QoS) guarantees in a multi-user OFDMA system. contrast to existing works on QoS-aware scheduling, which mostly take sum throughput or total transmission power as optimization objectives, we formulate an problem maximize energy efficiency subject users' QoS requirements. Based Lagrangian duality then, effective algorithm named proposed address problem. Simulation results show that our can...

In coherent optical communication systems, the transmitter usually employs an in-phase and quadrature (IQ) modulator to perform electrical-to-optical up-conversion. However, some environmental factors, such as temperature mechanical stress, strongly influence stability. To stabilize quality of transmitted signal, auto bias control (ABC) is essential keep in optimum bias. this paper, we present a novel method ABC for orthogonal frequency division multiplexing (O-OFDM) signal. proposed scheme,...

This paper details the software architecture of Berkeley unmanned aerial vehicle (UAV) platform. Developed over course three years, this platform has successfully demonstrated autonomous vision-based navigation and obstacle avoidance. A been developed to allow for collaborative control concepts be examined. modular shown effective use in allowing a team UAVs collaboratively perform set missions. The performance was using 3 patrolling

The development of small, autonomous UAVs that can operate in complex environments as part large coordinated groups will enable many new applications at fractions the cost current systems. A fleet fixed-wing aircraft has been developed to create an intelligent aerial platform demonstrated various capabilities. By means a downward-looking camera, single autonomously follows roadway using natural features scene conjunction with onboard sensors, without use GPS or prior knowledge road’s...

Multiband discrete Fourier transform spread (DFT-S) is a promising technology to reduce peak-to-average power ratio and mitigate the fiber nonlinearity. We investigate DFT-S coherent optical orthogonal frequency division multiplexing (CO-OFDM) in terms of computational complexity With nonlinearity improvement, 450-Gb/s two-band CO-OFDM outperforms conventional CO-OFDM, successfully transmitted over 9280-km link.

Collaborating unmanned aerial vehicles can e‐ciently perform surveillance, mapping, and other tasks without human risk. Currently deployed demonstrate a need for increased autonomy cooperation. We present UAV software architecture hardware platform that have demonstrated single-user control of ∞eet aircraft, distributed task assignment, vision-based navigation. A modular infrastructure has been developed to coordinate control, communications, control. Along with the onboard architecture, set...

We extended a pilot symbol frequency offset estimation scheme and applied it in combination with subcarrier compensator. Optimum system sensitivity was found up to few 100MHz offset.

Time-division duplex (TDD) systems rely on off-chip transmit/receive (T/R) switches to isolate the RX from high-output power of TX, while existing on-chip T/R switching solutions are narrow-band or high loss. This paper presents a wideband integrated technique that eliminates conventional, lossy series switch signal path. The system reconfigures PA as an LNA during receive mode, and utilizes only DC mode control enable TDD co-existence. To demonstrate this technique, polar transmitter can be...

We experimentally demonstrate a sub-band wavelength conversion scheme based on four-wave mixing in high-nonlinear fiber for multiple Tb/s-class superchannel coherent optical orthogonal frequency-division multiplexing networks. Combined with the selective switches reconfigurable add/drop multiplexers, overlapped spectra are efficiently relocated and almost seamlessly formed into new very little spectral efficiency degradation.

Energy efficiency has currently become one of the central topics in today's wireless communication industry. In this paper, we focus on energy-efficient design downlink multi-user MIMO-OFDM systems, so as to optimize energy with users' quality service (QoS) guarantees. Particularly, an optimization problem concerning power allocation is formulated, where objective measured by "Bit per Joule" and constraints are QoS demands. Based a mathematical equivalence Lagrange duality, propose effective...

We demonstrate a novel long-reach PON downstream scheme based on the regenerated pilot assisted direct-detection optical orthogonal frequency division multiplexing (DDO-OFDM) superchannel transmission. use comb source to form DDO-OFDM superchannel, and reserve center carrier as seed pilot. The is further tracked reused generate multiple carriers at local exchange. Each selected beat with an adjacent OFDM sub-band ONU, so that electrical bandwidth limitation can be much released compared...

SUMMARY We develop a model of firms' auditor choices when presented with heterogeneous group investors. show that in equilibrium depend on the composition investors market. The signaling effect choosing high-quality exists only there is at least certain proportion sophisticated If sufficiently high investors, then all firms will choose auditors. also overall audit quality market increases an increasing When differentiated and are heterogeneous, increase penalty for receive qualified opinion...

The development of high-performance tunnel junctions is critical for achieving high efficiency in multi-junction solar cells (MJSC) that can operate at concentrations. We investigate silicon and tellurium co-doping InGaAs quantum well inserts p++-GaAs/n++-GaAs report a peak current density as 5839 A cm−2 with series resistance 5.86 × 10−5 Ω cm2. In addition, we discuss how device performance affected by the growth temperature, thickness, V/III ratio layer. simulation model indicates...

In this paper, the impact of multiuser diversity for V-BLAST based OFDM systems in frequency selective fading channel is considered, and a subcarrier allocation criterion developed aimed to optimizing system-level performance. Mathematical analyses numeric simulations demonstrate that proposed assignment strategy outperforms static scheme significantly, even with little amount feedback. order guarantee users' quality service (QoS), reallocation algorithm given, it behaves well our experiments.

VCSEL (vertical cavity surface emitting laser) is a promising optoelectronic device, but its high manufacturing cost limits scope of applications. Growing on larger size wafers an effective way to reduce the cost. However, growth rate uniformity needs be optimized ensure devices’ performance over wafers. This paper investigates factors which influence using 8 × 6 inch planetary reactor through experiments and simulations. At carrier gas flow 37 slm, AsH3 600 sccm, ratio 100:500, ceiling...

Efficient path planning is the key enabling technology for realization of intelligent transportation systems (ITS). However, due to poor real-time performance and lack effective incentive methods, it difficult traditional schemes significantly improve efficiency traffic management. In addition, existing solutions that use driving distance time as indicators cannot meet personalized requirements vehicle users. To this end, by considering users, we propose a digital-twin (DT) enabled scheme...

This paper has an investigation on the transmittance characteristic of all-dielectric thin film Fabry-Perot filter (AFPF). When AFPF is rotated around a pivot point, linear relationship achieved between its peak-transmittance wavelength and cosine value incident angle laser beam. Based result, we propose new configuration with in external cavity diode (ECDL), which expected to achieve tuning over 40 nm range 1550 without mode hopping. The ECDL can be used application environmental...

A 2.5Gb/s/λ bi-directional coherent UDWDM-PON is demonstrated with 4-ASK modulation using heterodyne detection. The frequency offset tolerance around 6 GHz within 0.5-dB penalty, and no EDFA needed in either ONU or OLT.

A connected-(r,s)-out-of-(m,n): F system is a kind of the connected-X-out-of-(m,n): defined by Boehme et al. [2]. consists m×n components arranged in (m,n)-matrix. This fails if and only there exists grid size r×s which all are failed. When m=r, this can be regarded as consecutive-s-out-of-n: system, then optimal arrangement satisfies theorem stated Malon [9] case s=2. In study, we proposed new algorithm for obtaining connected-(r,2)-out-of-(m,n): based on above mentioned idea. We performed...