Qianyun Zhang

Stacked Patch Antenna With Dual-Polarization and Low Mutual Coupling for Massive MIMO

Massive multiple input and multiple output (MIMO) has attracted significant interests in both academia and industry. It has been considered as one of most promising technologies for 5G wireless systems. The large-scale antenna array for base stations naturally becomes the key to deploy the Massive MIMO technologies. In this communication, we present a dual-polarized antenna array with 144 ports for Massive MIMO operating at 3.7 GHz. The proposed array consists of 18 low profile subarrays. Each subarray consists of four single units. Each single antenna unit consists of one vertically polarized port and one horizontally polarized port connected to power splitters, which serve as a feeding network. A stacked patch design is used to construct the single unit with the feeding network, which gives higher gain and lower mutual coupling within the size of a conversional dual-port patch antenna. Simulation results of the proposed single antenna unit, sub-array, and Massive MIMO array are verified by measurement.

Some Initial Results and Observations from a Series of Trials within the Ofcom TV White Spaces Pilot

TV White Spaces (TVWS) technology allows wireless devices to opportunistically use locally-available TV channels enabled by a geolocation database. The UK regulator Ofcom has initiated a pilot of TVWS technology in the UK. This paper concerns a large- scale series of trials under that pilot. The purposes are to test aspects of white space technology, including the white space device and geolocation database interactions, the validity of the channel availability/powers calculations by the database and associated interference effects on primary services, and the performances of the white space devices, among others. An additional key purpose is to perform research investigations such as on aggregation of TVWS resources with conventional resources and also aggregation solely within TVWS, secondary coexistence issues and means to mitigate such issues, and primary coexistence issues under challenging deployment geometries, among others. This paper provides an update on the trials, giving an overview of their objectives and characteristics, some aspects that have been covered, and some early results and observations.

Compact Quad-Mode Bandpass Filter Based on Quad-Mode DGS Resonator

In this letter, a quad-mode bandpass filter is built up based on a novel quad-mode defected ground structure (DGS) resonator which has two symmetric planes. The odd-/even-mode theory is applied to analyze the operating principle of the four resonances with their equivalent circuit models. The four resonances can be effectively tuned by adjusting the corresponding dimensions. The fabricated filter has a center frequency of 2.45 GHz and a wide stopband up to 7.8 GHz with a rejection below -30 dB, which extends to at least 30 GHz below -16 dB. Particularly, the filter exhibits an excellent attenuation slope of 302 dB/GHz in the upper passband transition.

Miniaturized UHF Antenna using a magneto-dielectric superstrate for M2M communications

This paper presents a miniaturized antenna for ultra high frequency (UHF) Machine-to-Machine (M2M) communications. Basic structure of the antenna is a printed monopole fed through a microstrip line. A magneto-dielectric material MF114 is used as superstrate to achieve antenna miniaturization as well as increase its bandwidth. This antenna works at 480MHz, and has 8.3MHz bandwidth. Dimension of its whole structure is 60mm×60mm×4mm, length and width of the antenna is just 0.097λ × 0.097λ. The proposed antenna is promising to be integrated into compact nodes for M2M communications.

Compact U-shape ultra-wideband antenna with characteristic mode analysis for TV white space communications

In this paper, a printed monopole working at ultra-high frequency (UHF) is designed for TV white space (TVWS) applications. By employing U-shape radiator, tapered feeding and notched ground plane, impedance matching of the antenna is improved and its size is reduced. The proposed antenna achieves 414MHz bandwidth within a dimension as compact as 231mm × 35mm × 0.8mm. Furthermore, characteristic mode analysis (CMA) is applied to understand how the presented structure fulfils its ultra-wideband (UWB) property.

Miniaturized Antenna Array with Co 2 Z Hexaferrite Substrate for Massive MIMO

In this paper, a miniaturized microstrip circular patch antenna operating at 1.8 GHz for 3GPP LTE communication has been designed. This antenna adopts Co2Z hexaferrite as substrate, which has permeability σr=4 and permittivity εr=12 at 1.8 GHz. It achieves both antenna miniaturization and bandwidth enhancement with patchs radius λ/26 and 61 MHz -10-dB bandwidth. Subsequently, the single antenna is extended to antenna arrays with 2, 4, and 16 elements, and all of them meet requirements for a LTE communication. The proposed arrays are very compact for potential applications in Massive MIMO systems.

Dynamic Adaptive Video Streaming on Heterogeneous TVWS and Wi-Fi Networks

Nowadays, people usually connect to the Internet through a multitude of different devices. Video streaming takes the lion’s share of the bandwidth, and represents the real challenge for the service providers and for the research community. At the same time, most of the connections come from indoor, where Wi-Fi already experiences congestion and coverage holes, directly translating into a poor experience for the user. A possible relief comes from the TV white space (TVWS) networks, which can enhance the communication range thanks to sub-GHz frequencies and favorable propagation characteristics, but offer slower datarates compared with other 802.11 protocols. In this paper, we show the benefits that TVWS networks can bring to the end user, and we present CABA, a connection aware balancing algorithm able to exploit multiple radio connections in the favor of a better user experience. Our experimental results indicate that the TVWS network can effectively provide a wider communication range, but a load balancing middleware between the available connections on the device must be used to achieve better performance. We conclude this paper by presenting real data coming from field trials in which we streamed an MPEG dynamic adaptive streaming over HTTP video over TVWS and Wi-Fi. Practical quantitative results on the achievable quality of experience for the end user are then reported. Our results show that balancing the load between Wi-Fi and TVWS can provide a higher playback quality (up to 15% of average quality index) in scenarios in which the Wi-Fi is received at a low strength.

TV White Space Network Provisioning with Directional and Omni-Directional Terminal Antennas

Operating at ultra-high frequency (UHF), TV white space (TVWS) can achieve long-distance communication and good in-building penetration, and has attracted increasing attention of regulators, researchers and stakeholders. This paper explores the potential of TVWS for network provisioning within a cluster of buildings, through a succession of tests. Different transmission distances, from 10m to over 120m, and through multiple layers of walls as well as complex transmission environment imposed by other factors like office and construction facilities, are considered. Further, a compact ultra-wide band (UWB) printed monopole antenna is designed for the client white space terminal, and compared with a commercial directional UHF antenna on the same client. Measurement results show that the in-house compact antenna achieves fast network speed and a high signal-to-interference-plus-noise ratio (SINR), and it is orientation independent.

2016 IEEE 84th Vehicular Technology Conference, VTC Fall 2016 - Proceedings

Operating at ultra-high frequency (UHF), TV white space (TVWS) can achieve long-distance communication and good in-building penetration, and has attracted increasing attention of regulators, researchers and stakeholders. This paper explores the potential of TVWS for network provisioning within a cluster of buildings, through a succession of tests. Different transmission distances, from 10m to over 120m, and through multiple layers of walls as well as complex transmission environment imposed by other factors like office and construction facilities, are considered. Further, a compact ultra-wide band (UWB) printed monopole antenna is designed for the client white space terminal, and compared with a commercial directional UHF antenna on the same client. Measurement results show that the in-house compact antenna achieves fast network speed and a high signal-to-interference-plus-noise ratio (SINR), and it is orientation independent.

IEEE Vehicular Technology Conference 2016-Fall (VTC 2016-Fall), 2016 IEEE 84th

Operating at ultra-high frequency (UHF), TV white space (TVWS) can achieve long-distance communication and good in-building penetration, and has attracted increasing attention of regulators, researchers and stakeholders. This paper explores the potential of TVWS for network provisioning within a cluster of buildings, through a succession of tests. Different transmission distances, from 10m to over 120m, and through multiple layers of walls as well as complex transmission environment imposed by other factors like office and construction facilities, are considered. Further, a compact ultra-wide band (UWB) printed monopole antenna is designed for the client white space terminal, and compared with a commercial directional UHF antenna on the same client. Measurement results show that the in-house compact antenna achieves fast network speed and a high signal-to-interference-plus-noise ratio (SINR), and it is orientation independent.