accessTechRxiv.pdf

2019 ◽  
Author(s):  
José P. González-Coma ◽  
Luis Castedo
Keyword(s):  
Power Efficiency ◽  
Scheduling Algorithm ◽  
Multiple Input Multiple Output ◽  
Computer Experiments ◽  
Phase Shifters ◽  
Power Efficient ◽  
Input Multiple Output ◽  
Analog Transmission ◽  
Insertion Losses ◽  
Reduced Power Consumption

We consider power efficient scheduling and precoding solutions for multiantenna hybrid digital-analog transmission systems that use Time-Modulated Arrays (TMAs) in the analog domain. TMAs perform beamforming with switches instead of conventional Phase Shifters (PSs). The extremely low insertion losses of switches, together with their reduced power consumption and cost make TMAs attractive in emerging technologies like massive Multiple-Input Multiple-Output (MIMO) and millimeter wave (mmWave) systems. We propose a novel analog processing network based on TMAs and provide an angular scheduling algorithm that overcomes the limitations of conventional approaches. Next, we pose a convex optimization problem to determine the analog precoder. This formulation allows us to account for the Sideband Radiation (SR) effect inherent to TMAs, and achieve remarkable power efficiencies with a very low impact on performance. Computer experiments results show that the proposed design, while presenting a significantly better power efficiency, achieves a throughput similar to that obtained with other strategies based on angular selection for conventional architectures.<br>

Power Efficient Scheduling and Hybrid Precoding for Time Modulated Arrays

2019 ◽  
Author(s):  
José P. González-Coma ◽  
Luis Castedo
Keyword(s):  
Power Efficiency ◽  
Scheduling Algorithm ◽  
Multiple Input Multiple Output ◽  
Computer Experiments ◽  
Phase Shifters ◽  
Power Efficient ◽  
Input Multiple Output ◽  
Analog Transmission ◽  
Insertion Losses ◽  
Reduced Power Consumption

We consider power efficient scheduling and precoding solutions for multiantenna hybrid digital-analog transmission systems that use Time-Modulated Arrays (TMAs) in the analog domain. TMAs perform beamforming with switches instead of conventional Phase Shifters (PSs). The extremely low insertion losses of switches, together with their reduced power consumption and cost make TMAs attractive in emerging technologies like massive Multiple-Input Multiple-Output (MIMO) and millimeter wave (mmWave) systems. We propose a novel analog processing network based on TMAs and provide an angular scheduling algorithm that overcomes the limitations of conventional approaches. Next, we pose a convex optimization problem to determine the analog precoder. This formulation allows us to account for the Sideband Radiation (SR) effect inherent to TMAs, and achieve remarkable power efficiencies with a very low impact on performance. Computer experiments results show that the proposed design, while presenting a significantly better power efficiency, achieves a throughput similar to that obtained with other strategies based on angular selection for conventional architectures.<br>

scholarly journals Power Efficient Scheduling and Hybrid Precoding for Time Modulated Arrays

2019 ◽  
Author(s):  
José P. González-Coma ◽  
Luis Castedo
Keyword(s):  
Power Efficiency ◽  
Scheduling Algorithm ◽  
Multiple Input Multiple Output ◽  
Computer Experiments ◽  
Phase Shifters ◽  
Power Efficient ◽  
Input Multiple Output ◽  
Analog Transmission ◽  
Insertion Losses ◽  
Reduced Power Consumption

We consider power efficient scheduling and precoding solutions for multiantenna hybrid digital-analog transmission systems that use Time-Modulated Arrays (TMAs) in the analog domain. TMAs perform beamforming with switches instead of conventional Phase Shifters (PSs). The extremely low insertion losses of switches, together with their reduced power consumption and cost make TMAs attractive in emerging technologies like massive Multiple-Input Multiple-Output (MIMO) and millimeter wave (mmWave) systems. We propose a novel analog processing network based on TMAs and provide an angular scheduling algorithm that overcomes the limitations of conventional approaches. Next, we pose a convex optimization problem to determine the analog precoder. This formulation allows us to account for the Sideband Radiation (SR) effect inherent to TMAs, and achieve remarkable power efficiencies with a very low impact on performance. Computer experiments results show that the proposed design, while presenting a significantly better power efficiency, achieves a throughput similar to that obtained with other strategies based on angular selection for conventional architectures.<br>

All-in-one silicon photonic polarization processor

Nanophotonics ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 2257-2267 ◽  
Author(s):  
Hailong Zhou ◽  
Yuhe Zhao ◽  
Yanxian Wei ◽  
Feng Li ◽  
Jianji Dong ◽  
...  
Keyword(s):  
Large Scale ◽  
Optical Network ◽  
Multiple Input Multiple Output ◽  
Building Blocks ◽  
Phase Shifters ◽  
Single Function ◽  
Gradient Descent Algorithm ◽  
Input Multiple Output ◽  
Polarization Functions ◽  
The Cost

AbstractWith the great developments in optical communication technology and large-scale optical integration technology, it is imperative to realize the traditional functions of polarization processing on an integration platform. Most of the existing polarization devices, such as polarization multiplexers/demultiplexers, polarization controllers, polarization analyzers, etc., perform only a single function. Definitely, integrating all these polarization functions on a chip will increase function flexibility and integration density and also cut the cost. In this article, we demonstrate an all-in-one chip-scale polarization processor based on a linear optical network. The polarization functions can be configured by tuning the array of phase shifters on the chip. We demonstrate multiple polarization processing functions, including those of a multiple-input-multiple-output polarization descrambler, polarization controller, and polarization analyzer, which are the basic building blocks of polarization processing. More functions can be realized by using an additional two-dimensional output grating. A numerical gradient descent algorithm is employed to self-configure and self-optimize these functions. Our demonstration suggests great potential for chip-scale, reconfigurable, and fully programmable photonic polarization processors with the artificial intelligence algorithm.

scholarly journals A Review of 5G Power Amplifier Design at cm-Wave and mm-Wave Frequencies

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
D. Y. C. Lie ◽  
J. C. Mayeda ◽  
Y. Li ◽  
J. Lopez
Keyword(s):  
Power Amplifier ◽  
Power Efficiency ◽  
Low Cost ◽  
Multiple Input Multiple Output ◽  
Wave Spectrum ◽  
System Architectures ◽  
Mimo Antennas ◽  
Rf Transmitters ◽  
Input Multiple Output ◽  
Amplifier Design

The 5G wireless revolution presents some dramatic challenges to the design of handsets and communication infrastructures, as 5G targets higher than 10 Gbps download speed using millimeter-wave (mm-Wave) spectrum with multiple-input multiple-output (MIMO) antennas, connecting densely deployed wireless devices for Internet-of-Everything (IoE), and very small latency time for ultrareliable machine type communication, etc. The broadband modulation bandwidth for 5G RF transmitters (i.e., maximum possibly even above 1 GHz) demands high-power efficiency and stringent linearity from its power amplifier (PA). Additionally, the phased-array MIMO antennas with numerous RF front-ends (RFFEs) will require unprecedented high integration level with low cost, making the design of 5G PA one of the most challenging tasks. As the centimeter-wave (cm-Wave) 5G systems will probably be deployed on the market earlier than their mm-Wave counterparts, we will review in this paper the latest development on 15 GHz and 28 GHz 5G cm-Wave PAs extensively, while also covering some key mm-Wave PAs in the literature. Our review will focus on the available options of device technologies, novel circuit and system architectures, and efficiency enhancement techniques at power back-off for 5G PA design.

scholarly journals Iterative Analog–Digital Multi-User Equalizer for Wideband Millimeter Wave Massive MIMO Systems

Sensors ◽  
2020 ◽  
Vol 20 (2) ◽  
pp. 575 ◽  
Author(s):  
Roberto Magueta ◽  
Daniel Castanheira ◽  
Pedro Pedrosa ◽  
Adão Silva ◽  
Rui Dinis ◽  
...  
Keyword(s):  
Millimeter Wave ◽  
Massive Mimo ◽  
Mimo Systems ◽  
Multiple Input Multiple Output ◽  
Hybrid Approach ◽  
Efficient Solutions ◽  
Phase Shifters ◽  
Sequential Approach ◽  
Input Multiple Output ◽  
Narrowband Channels

Most of the previous work on hybrid transmit and receive beamforming focused on narrowband channels. Because the millimeter wave channels are expected to be wideband, it is crucial to propose efficient solutions for frequency-selective channels. In this regard, this paper proposes an iterative analog–digital multi-user equalizer scheme for the uplink of wideband millimeter-wave massive multiple-input-multiple-output (MIMO) systems. By iterative equalizer we mean that both analog and digital parts are updated using as input the estimates obtained at the previous iteration. The proposed iterative analog–digital multi-user equalizer is designed by minimizing the sum of the mean square error of the data estimates over the subcarriers. We assume that the analog part is fixed for all subcarriers while the digital part is computed on a per subcarrier basis. Due to the complexity of the resulting optimization problem, a sequential approach is proposed to compute the analog phase shifters values for each radio frequency (RF) chain. We also derive an accurate, semi-analytical approach for obtaining the bit error rate (BER) of the proposed hybrid system. The proposed solution is compared with other hybrid equalizer schemes, recently designed for wideband millimeter-wave (mmWave) massive MIMO systems. The simulation results show that the performance of the developed analog–digital multi-user equalizer is close to full-digital counterpart and outperforms the previous hybrid approach.

scholarly journals Distributed Link Scheduling Algorithm Based on Successive Interference Cancellation in MIMO Wireless Networks

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Junhua Wu ◽  
Dandan Lin ◽  
Guangshun Li ◽  
Yuncui Liu ◽  
Yanmin Yin
Keyword(s):  
Wireless Networks ◽  
Interference Cancellation ◽  
Scheduling Algorithm ◽  
Multiple Input Multiple Output ◽  
Successive Interference Cancellation ◽  
Sensor Nodes ◽  
Link Scheduling ◽  
Mathematical Framework ◽  
Routing And Scheduling ◽  
Input Multiple Output

The performance of multiple input multiple output (MIMO) wireless networks is limited mainly by concurrent interference among sensor nodes. Effective link scheduling algorithms with the technology of successive interference cancellation (SIC) can maximize throughput in MIMO wireless networks. Most previous works on link scheduling in MIMO wireless networks did not consider SIC. In this paper, we propose a MIMO-SIC (MSIC) algorithm under the SINR model. First, a mathematical framework is established for the cross-layer optimization of routing and scheduling, with constraints of traffic balance and link capacity. Second, the interference regions are divided to characterize the level of interference between links. Finally, we propose a distributed link scheduling algorithm based on MSIC to eliminate the interference between competing links in the MIMO network. Experimental results show that the MSIC algorithm can increase the end-to-end throughput per unit by approximately 73% on average compared with non-SIC algorithms.

scholarly journals Optimized Scheduling Technique of Null Subcarriers for Peak Power Control in 3GPP LTE Downlink

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Soobum Cho ◽  
Sang Kyu Park
Keyword(s):  
Power Efficiency ◽  
Multiple Access ◽  
Mimo Systems ◽  
Multiple Input Multiple Output ◽  
Average Power ◽  
Papr Reduction ◽  
Single Input Single Output ◽  
Single Output ◽  
Multiple Input ◽  
Input Multiple Output

Orthogonal frequency division multiple access (OFDMA) is a key multiple access technique for the long term evolution (LTE) downlink. However, high peak-to-average power ratio (PAPR) can cause the degradation of power efficiency. The well-known PAPR reduction technique, dummy sequence insertion (DSI), can be a realistic solution because of its structural simplicity. However, the large usage of subcarriers for the dummy sequences may decrease the transmitted data rate in the DSI scheme. In this paper, a novel DSI scheme is applied to the LTE system. Firstly, we obtain the null subcarriers in single-input single-output (SISO) and multiple-input multiple-output (MIMO) systems, respectively; then, optimized dummy sequences are inserted into the obtained null subcarrier. Simulation results show that Walsh-Hadamard transform (WHT) sequence is the best for the dummy sequence and the ratio of 16 to 20 for the WHT and randomly generated sequences has the maximum PAPR reduction performance. The number of near optimal iteration is derived to prevent exhausted iterations. It is also shown that there is no bit error rate (BER) degradation with the proposed technique in LTE downlink system.

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