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The key objective of the fifth generation (5G) wireless technology is to support services with highly diverse requirements, which necessitates the specification of flexible numerology and frame structure for radio resource allocation in 5G new radio (NR). In this article, flexible 2-dimensional resource allocation is investigated to exploit the frequency and time diversities of the resource grid, and eventually maximize the overall system energy efficiency (EE) in the scenario where enhanced mobile broadband (eMBB) and ultra-reliable and low latency communication (URLLC) services coexist. A new definition of EE is proposed to capture and fulfill the heterogeneous quality-of-service (QoS) requirements of eMBB and URLLC services. By first sliding a window on the resource grid to determine the candidate resource pool, and then allocating resource blocks (RBs) therein by leveraging linear programming (LP) relaxation, we propose a sliding window (SW) based algorithm with a low complexity for the NP-hard EE optimization problem. In addition, we also analyze the achievable EE performance of the proposed algorithm to demonstrate its scalability with respect to the grid sizes and the maximum transmit power to provide an in-depth understanding. Numerical results show that the proposed algorithm can bring about as much as 16.7% power consumption reduction, and improve EE by about 29.3% compared to other baseline systems.

The key objective of the fifth generation (5G) wireless technology is to support services with vastly variable requirements, which necessitates the flexible numerology and frame structure for radio resource allocation. In this paper, flexible 2-dimensional resource allocation is investigated to maximize the energy efficiency (EE) for service transmissions with heterogeneous latency requirements. Exploiting the frequency and time diversities of the resource grid, frequency-selective resource allocation, together with an agile "on-off" operation of the power amplifier (PA) are performed by the proposed sliding window-based (SW) algorithm with scalability. Simulation results further demonstrate that the SW algorithm can achieve similar EE performance as the exhaustive method with a substantially lower complexity.

Based on the synergy of a theoretical one-dimensional (1D) mass-spring-damper model and the experimental validation of fabricated capacitive MEMS microphones fabricated by the PolyMUMPs process, we identify the existence of a critical diaphragm radius which represents the inflection point on the microphone's sensitivity-radius curve. To overcome this miniaturization barrier, we propose a new microphone structure with four folded microbeams. The corresponding sensitivity remains the same, while the radius reduces by 17% in comparison with the previous design.

We present a comparative study of the viscoelasticity of parylene C (PPXC) by using Nano-DMA (Dynamical Mechanical Analysis) and Molecular Dynamics (MD) simulations. By applying sinusoidal loading on PPXC films at different temperatures and frequencies, the complex modulus and glass transition temperature (T g ) of the PPXC were obtained. The predicted T g determined from the temperature-dependent density change in the MD model is consistent with the results in our measurements and previous works. Furthermore, with Time-Temperature Superposition Principle (TTSP), we successfully determined the master curve of PPXC, for the first time, which is critical for the parylene reliability study of bio-MEMS devices.

Residual stress during the micro-fabrication process has been one of the main issues in many MEMS/NEMS sensors and actuators, especially acoustic sensing. We conduct theoretical, numerical and experimental study on the residual stress effect on the frequency responses of two types of polysilicon micro circular resonators: clamped and residual stress (RS) free design which can release the process-induced stress and is of easy fabrication. The measured natural frequency of the fabricated device is 39.8 kHz, in good agreement with both theoretical and FEM simulation results. We also determined the natural frequencies of these two designs as a function of residual stress. Under the same experimental RS condition of 50 MPa, the normalized changes of natural frequencies of these two designs are 159.7% versus 0.8%, respectively.