RF Front‐End Circuits and Architectures for IoT/LTE‐A/5G Connectivity

Abstract

g., smart city) have been driving the evolution of wireless communications. With ever-increasing demand for higher data rates, service carriers have improved the existing 4th-generation (4G) networks with carrier aggregation and multi-input multi-output (MIMO) antenna techniques, the key features of LTE-Advanced (LTE-A). To evolve beyond 4G, the 5th-generation (5G) networks need to be scalable, versatile, and energy-smart for the hyperconnected IoE world. By employing advanced modulation schemes, massive MIMO, beamforming, and mmWave carriers, the 5G connectivity is expected to achieve significantly enhanced data rate (10 Gbps peak data rate), universal coverage, spectral/spatial diversity/efficiency, and/or minimized latency (sub-1ms).The emerging connectivity applications have imposed new yet stringent specs to the design of RF front-ends. Furthermore, due to various market factors, designers are facing additional complexities such as multiband, multimode (2G/3G/4G/LTE-A/5G, WiFi, Bluetooth, GPS, etc.), small form factor while balancing cost competitiveness, ever-better performance, and longer battery life. Overcoming these challenges requires high performance innovative solutions.The motivation of this special issue is to publish the state-of-the-art RF circuit and architecture solutions to help address the design challenges of the IoT/LTE-A/5G connectivity. After a rigorous two-round review process, 6 outstanding papers have been accepted for inclusion in this special issue. The accepted papers cover a wide range of research subjects in RF/mmWave circuits and architectures to meet the increasing demands of 5G and beyond.The paper entitled "A Review of 5G Power Amplifier Design at cm-Wave and mm-Wave Frequencies" by Dr. D. Y. C. Lie et al. surveyed some advanced 5G power amplifier (PA) designs in various device technologies including wideband Doherty PA in GaAs and in SiGe; stacked PA on SOI CMOS; differential bulk CMOS PA with neutralization cap and transformers; CMOS DPA (digital PA); fully monolithic GaN PA; highly integrated RFFE with LNA, PA, phase shifter, switches for phased-array MIMO, and so forth. These PA designs present potential solutions for successful cmWave and mmWave 5G front-end IC designs.The paper entitled "A Low Power Impedance Transparent Receiver with Linearity Enhancement Technique for IoT Applications" by S. Chen et al. presented a reconfigurable receiver (Rx) with tunable channel filtering and narrowband input matching at the Rx input. The passive mixer and active feedback LNA are used in the receiver to further transfer the baseband impedance to Rx input. A 3rd-order active-RC filter is designed with current-efficient feedforward compensated OTA. The digital-to-time converter (DTC) assisted fractional-N all-digital phase-locked loop (ADPLL) is codesigned with the receiver to meet the IoT requirements. By utilizing blocker filtering and derivative superposition techniques, the proposed receiver architecture achieves

Securing 5G-IoT Device Connectivity and Coverage Using Boltzmann Machine Keys Generation

“…More temporary keys consume less memory and drastically lower machine requirements. With a 256-bit key and 256-bit primary curve, ECC [26] is comparable to RSA 2048. As part of the overall security solution, key agreements, asymmetric authentication encryption, hash codes, and digital signatures are used to secure 5G-IoT Device Connectivity and Coverage suites.…”

Designing and Calculating Bandwidth of the LTE Network for Rural Areas

“…Fig. 6 Exterior view of the Cisco 7603 OSR router [23] The regulation of subscriber sessions and services in LTE networks is carried out with the support of the core packet network EPC (Evolved Packet Core) [27], [28]. The Cisco ASR 5000 Router Type is designed specifically for broadband networks.…”

Doherty Amplifier Design Based on Asymmetric Configuration Scheme

“…However, to obtain the full 5G specifications-higher data rate, low latency, and more numerous connections-hardware devices for the 5G or beyond-5G technology have to be further developed. For such communication systems, wideband digital modulation signals with a large peak-to-average power ratio are used, which has to be efficiently handled in microwave power amplifiers, especially at higher operation frequencies [1], [2]. Doherty power amplifiers [3]- [13] are commonly used for wideband communication systems, owing to their wide dynamic range performance.…”