Energy Efficiency Optimization of 5G Radio Frequency Chain Systems

With the massive multi-input multi-output (MIMO) antennas technology adopted for the fifth generation (5G) wireless communication systems, a large number of radio frequency (RF) chains have to be employed for RF circuits. However, a large number of RF chains not only increase the cost of RF circuits but also consume additional energy in 5G wireless communication systems. In this paper we investigate energy and cost efficiency optimization solutions for 5G wireless communication systems with a large number of antennas and RF chains. An energy efficiency optimization problem is formulated for 5G wireless communication systems using massive MIMO antennas and millimeter wave technology. Considering the nonconcave feature of the objective function, a suboptimal iterative algorithm, i.e., the energy efficient hybrid precoding (EEHP) algorithm is developed for maximizing the energy efficiency of 5G wireless communication systems. To reduce the cost of RF circuits, the energy efficient hybrid precoding with the minimum number of RF chains (EEHP-MRFC) algorithm is also proposed. Moreover, the critical number of antennas searching (CNAS) and user equipment number optimization (UENO) algorithms are further developed to optimize the energy efficiency of 5G wireless communication systems by the number of transmit antennas and UEs. Compared with the maximum energy efficiency of conventional zero-forcing (ZF) precoding algorithm, numerical results indicate that the maximum energy efficiency of the proposed EEHP and EEHP-MRFC algorithms are improved by 220% and 171%, respectively.Comment: 16 pages, 7 figure

Energy Efficient ADC Bit Allocation and Hybrid Combining for Millimeter Wave MIMO Systems

Low resolution analog-to-digital converters (ADCs) can be employed to improve the energy efficiency (EE) of a wireless receiver since the power consumption of each ADC is exponentially related to its sampling resolution and the hardware complexity. In this paper, we aim to jointly optimize the sampling resolution, i.e., the number of ADC bits, and analog/digital hybrid combiner matrices which provides highly energy efficient solutions for millimeter wave multiple-input multiple output systems. A novel decomposition of the hybrid combiner to three parts is introduced: the analog combiner matrix, the bit resolution matrix and the baseband combiner matrix. The unknown matrices are computed as the solution to a matrix factorization problem where the optimal, fully digital combiner is approximated by the product of these matrices. An efficient solution based on the alternating direction method of multipliers is proposed to solve this problem. The simulation results show that the proposed solution achieves high EE performance when compared with existing benchmark techniques that use fixed ADC resolutions

Energy Efficiency and Asymptotic Performance Evaluation of Beamforming Structures in Doubly Massive MIMO mmWave Systems

Future cellular systems based on the use of millimeter waves will heavily rely on the use of antenna arrays both at the transmitter and at the receiver. For complexity reasons and energy consumption issues, fully digital precoding and postcoding structures may turn out to be unfeasible, and thus suboptimal structures, making use of simplified hardware and a limited number of RF chains, have been investigated. This paper considers and makes a comparative assessment, both from a spectral efficiency and energy efficiency point of view, of several suboptimal precoding and postcoding beamforming structures for a cellular multiuser MIMO (MU-MIMO) system with large number of antennas. Analytical formulas for the asymptotic achievable spectral efficiency and for the global energy efficiency of several beamforming structures are derived in the large number of antennas regime. Using the most recently available data for the energy consumption of phase shifters and switches, we show that fully-digital beamformers may actually achieve a larger energy efficiency than lower-complexity solutions, as well as that low-complexity beam-steering purely analog beamforming may in some cases represent a good performance-complexity trade-off solution.Comment: Submitted to IEEE Transactions on Green Communications and Networkin

Energy Efficiency Maximization in Millimeter Wave Hybrid MIMO Systems for 5G and Beyond

At millimeter wave (mmWave) frequencies, the higher cost and power consumption of hardware components in multiple-input multiple output (MIMO) systems do not allow beamforming entirely at the baseband with a separate radio frequency (RF) chain for each antenna. In such scenarios, to enable spatial multiplexing, hybrid beamforming, which uses phase shifters to connect a fewer number of RF chains to a large number of antennas is a cost effective and energy-saving alternative. This paper describes our research on fully adaptive transceivers that adapt their behaviour on a frame-by-frame basis, so that a mmWave hybrid MIMO system always operates in the most energy efficient manner. Exhaustive search based brute force approach is computationally intensive, so we study fractional programming as a low-cost alternative to solve the problem which maximizes energy efficiency. The performance results indicate that the resulting mmWave hybrid MIMO transceiver achieves significantly improved energy efficiency results compared to the baseline cases involving analogue-only or digital-only signal processing solutions, and shows performance trade-offs with the brute force approach.Comment: 2020 IEEE International Conference on Communications and Networking (ComNet

ANALISIS PERFORMANSI PENGGUNAAN RF CHAIN TERHADAP EFISIENSI ENERGI MASSIVE MIMO PADA FREKUENSI 28 GHZ DI KANAL RICIAN

Dengan memanfaatkan lebih banyak antena dan frekuensi radio yang lebih tinggi, teknologi komunikasi 5G mampu meningkatkan system komunikasi namun di sisi yang lain turut meningkatkan dari segi penggunaan energi. Para peneliti berkonsentrasi untuk menemukan metode yang mampu mengonsumsi lebih sedikit energi, seperti mengurangi jumlah total RF chain. Ekosistem 5G memanfaatkan konsep Non-Orthogonal Multiple Access (NOMA) untuk menggunakan energi seefisien mungkin. Penelitian ini dilakukan dengan menggunakan daya sebesar 10 watt untuk menghubungkan dua pengguna di bawah kondisi pengimplementasikan teknologi NOMA dan kanal Rician pada frekuensi 28 GHz yang disimulasikan dalam percobaan menggunakan MATLAB r2020a. Hasilnya menunjukkan bahwa Signal-to-Noise Ratio (SNR) serta penggunaan jumlah antenna sangat penting dalam menghasilkan nilai efisiensi energi dan juga nilai ini dapat ditingkatkan dengan menggunakan RF chain yang lebih sedikit. Pengimplementasian RF chain seminimal mungkin dan NOMA dapat digabungkan untuk meningkatkan kinerja jaringan tanpa mengurangi efisiensi energi, membangun peluang untuk teknologi 5G berkinerja tinggi dan ramah lingkungan. ----- The 5G communication technology revolutionizes communication by using higher radio frequencies and more antennas, but also increases energy consumption. Researchers have focused on energy-efficient solutions using techniques like reducing the number of RF chains. The Non-Orthogonal Multiple Access (NOMA) idea is used to maximize energy use in the 5G ecosystem. An experiment using MATLAB r2020a simulated the consumption of 10 watts of power to link two users using NOMA technology at 28 GHz. Results showed that energy efficiency can be improved by using fewer RF chains, and the Signal-toNoise Ratio (SNR) is crucial for energy efficiency. Combining NOMA and intelligent RF chain management can enhance network performance without sacrificing energy efficiency, paving the way for high-performance and sustainable 5G technology. Keyword: energy efficiency, RF chain, NOMA, MMIM

A review on Precoding Techniques For mm-Wave Massive MIMO Wireless Systems

The growing demands for high data rate wireless connectivity shed lights on the fact that appropriate spectrum regions need to be investigated so that the expected future needs will be satisfied. With this in mind, the research community has shown considerable interest in millimeter-wave (mm-wave) communication. Generally, hybrid transceivers combining the analog phase shifter and the RF chains with digital signal processing (DSP) systems are used for MIMO communication in the fifth generation (5G) wireless networks. This paper presents a survey for different precoding or beamforming techniques that have been proposed in the literature. These beamforming techniques are mainly classified based on their hardware structure into analog and digital beamforming. To reduce the hardware complexity and power consumption, the hybrid precoding techniques that combine analog and digital beamforming can be implemented for mm-wave massive MIMO wireless systems. The performance of the most common hybrid precoding algorithms has been investigated in this paper