scholarly journals mmWave massive analog relay MIMO

2021 ◽  
Vol 2 (6) ◽  
pp. 43-55
Author(s):  
Kei Sakaguchi ◽  
Takumi Yoneda ◽  
Masashi Iwabuchi ◽  
Tomoki Murakami

Millimeter-Wave (mmWave) communications are a key technology to realize ultra-high data rate and ultra-low latency wireless communications. Compared with conventional communication systems in the microwave band such as 4G/LTE, mmWave communications employ a higher frequency band which allows a wider bandwidth and is suitable for large capacity communications. It is expected to be applied to various use cases such as mmWave cellular networks and vehicular networks. However, due to the strong diffraction loss and the path loss in the mmWave band, it is difficult or even impossible to achieve high channel capacity for User Equipment (UE) located in Non-Line-Of-Sight (NLOS) environments. To solve the problem, the deployment of relay nodes has been considered. In this paper, we consider the use of massive analog Relay Stations (RSs) to relay the transmission signals. By relaying the signals by a large number of RSs, an artificial Multiple-Input Multiple-Output (MIMO) propagation environment can be formed, which enables mmWave MIMO communications to the NLOS environment. We describe a theoretical study of a massive relay MIMO system and extend it to include multi-hop relays. Simulations are conducted, and the numerical results show that the proposed system achieves high data rates even in a grid-like urban environment.

2016 ◽  
Vol 78 (5-7) ◽  
Author(s):  
Mohd Syarhan Idris ◽  
Nur Idora Abdul Razak ◽  
Azlina Idris ◽  
Ruhani Ab Rahman

Multiple Input Multiple Output (MIMO) system has been brought a great improvement in spectral efficiency and the system capacity by serving multiple users simultaneously. The mathematical model of downlink Multi-user MIMO system and its capacity has been presented as well as different precoded transmission schemes. It is to implementing the downlink MU-MIMO system, such as channel inversion (CI), block diagonalization (BD), dirty paper coding (DPC) and tomlinsonharashimaprecoding (THP). It is because, in wireless and mobile communication system has been requires a reliable transmission of high data rates under various channel type different scenarios and reduce MU interference in the system.   These compares the method of transmission for broadcast channel (BC) and propose the best one method that outperforms existing technique with percentage improvement from the worst performance.


2017 ◽  
Vol 7 (1.1) ◽  
pp. 638
Author(s):  
Ashish Kumar Sarangi ◽  
Amrit Mukherjee ◽  
Amlan Datta

To achieve high capacity and high data rates is the main requirement for today’s generation. This paper studies about the performance and capacity comparison of MIMO and cooperative MIMO systems. The comparison of capacity between multiple- input- multiple- output (MIMO) and cooperative MIMO systems helps us to know that which system have better performance and better capacity. The simulation results shows that among SISO, SIMO, MISO and MIMO  system the capacity of MIMO will be better but in between MIMO and cooperative MIMO, Cooperative MIMO system have high capacity than MIMO systems.  


2019 ◽  
Author(s):  
◽  
Rami Issam El Mawla

Optical wireless communication (OWC) constitutes a key technology for 5G wireless networks. OWC alleviates the radio frequency (RF) spectrum crunch problem by enabling communications in the visible, infrared and ultraviolet optical frequency bands for a variety of indoor and outdoor applications. Outdoor infrared OWC systems are widely referred to as free-space optical (FSO) communications that rely on line-of-sight transmissions of narrow laser beams. The FSO technology is license-free, easy-to-deploy, cost-effective and capable of delivering very high data rates. The major impairment that severely degrades the performance of FSO links is related to the random aspect of the atmosphere. Overcoming atmospheric turbulence-induced fading became the key research area where many solutions have been proposed and analyzed. These solutions include the multiple-input-multiple-output (MIMO) techniques.


2008 ◽  
Vol 6 ◽  
pp. 55-61
Author(s):  
H. Rabe ◽  
D. Kornek ◽  
M. Stege ◽  
I. Rolfes

Abstract. The increasing interest in wireless transmission of highest data rates for multimedia applications (e.g. HDTV) demands the use of communication systems as e.g. described in the IEEE 802.11n draft specification for WLAN including spatial multiplexing or transmit diversity to achieve a constant high data rate and a small outage probability. In a wireless communications system the transmission of parallel data stream leads to multiple input/multiple output (MIMO) systems, whose key parameters heavily depend on the properties of the mobile channel. Assuming an uncorrelated channel matrix the correlation between the multiplexed data streams is caused by the coupling of the antennas, so that the radiation element becomes an even more important part of the system. Previous work in this research area (Klemp and Eul, 2006) has shown that planar log.-per four arm antennas are promising candidates for MIMO applications providing two nearly decorrelated radiators, which cover a wide frequency range including both WLAN bands at 2.4 GHz and 5.4 GHz. Up to now the MIMO performance of this antenna is mainly analyzed by simulations. In this contribution measured channel matrices in a real office environment are studied in terms of the antenna's MIMO performance such as outage probability. The obtained results recorded by using a commercial platform are compared to the simulated ones.


Author(s):  
A. Z. Yonis

<p><span lang="EN-US">IEEE 802.11ac based wireless local area network (WLAN) is emerging WiFi standard at 5 GHz, it is new gigabit-per-second standard providing premium services. IEEE 802.11ac accomplishes its crude speed increment by pushing on three distinct measurements firstly is more channel holding, expanded from a maximum of 80 MHz up to 160 MHz modes. Secondly, the denser modulation, now using 256-QAM, it has the ability to increase the data rates up to 7 Gbps using an 8×8 multiple input multiple output (MIMO). Finally, it provides high resolution for both narrow and medium bandwidth channels. This work presents a study to improve the performance of IEEE 802.11ac based WLAN system.</span></p>


2012 ◽  
Vol 459 ◽  
pp. 620-623
Author(s):  
Hong He ◽  
Tao Li ◽  
Tong Yang ◽  
Lin He

This article mainly describes a new technique of multiple-input multiple-output (MIMO) communication systems based on the recent communication demand. This technique, by pre-coding CSI (the channel state information) at the transmitter, is based on UCD (Uniform Channel Decomposition) algorithm for MIMO system. By Uniform Channel decomposition of channel matrix, the algorithm can decompose a MIMO downlink channel into multiple identical sub-channels. The power allocation applied to each sub channel in MIMO system is identical, and the MIMO channel’s capacity isn’t reduce when the SNR (Signal Noise Ratio) is low. The simulations show that the UCD scheme has a better performance than GMD (Geometric Mean Decomposition) scheme even without the use of error-correcting codes, and the Symbol Error Rate (SER) of UCD algorithm is lower than GMD’s at the same SNR. Consequently, MIMO system gets a better interference performance by UCD algorithm.


2020 ◽  
Vol 55 (6) ◽  
Author(s):  
Saif Saad Hameed ◽  
Fouad H. Awad ◽  
Adnan Yousif Dawod ◽  
Ayoob Abdulmunem Abdulhameed

The channel could be evaluated by utilizing several estimation algorithms. The various patterns of pilot arrangements for the channel appreciation are a huge problem in channel appreciation techniques since all the processes depends on it; this paper discusses improvements in channel selection. The Least Square and Least Square Mean methods are common, simple ways to begin to estimate a channel; however, they are less efficient than more complex approaches. Due to the boost in demand with high data rates in communications, developers continue to invent new methods and mechanisms to adjust the capacity and the accuracy of the communication network. One of the primary troubles in wireless communication is the communication channel, which is affected by nonlinear and random noise sources, which decrease the quality of the service on the network; in this case, the channel must be equalized to increase performance with minimal error. In this paper, a Massive Multiple Input Multiple Output was designed and simulated in order to estimate the channel and the performance of the network through using Least Square and Least Square Mean.


Electronics ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 55 ◽  
Author(s):  
Omar A. Saraereh ◽  
Imran Khan ◽  
Byung Moo Lee ◽  
Ashraf Tahat

Massive Multiple-input Multiple-output (MIMO) is an emerging technology for the 5G wireless communication systems which has the potential to provide high spectral efficient and improved link reliability and accommodate large number of users. Aiming at the problem of pilot contamination in massive MIMO systems, this paper proposes two algorithms to mitigate it. The first algorithm is depending on the idea of Path Loss to perform User Grouping (PLUG) which divide the users into the center and edge user groups depending on different levels of pilot contamination. It assigns the same pilot sequences to the center users which slightly suffer from pilot contamination and assign orthogonal pilot sequences to the edge users which severely suffer from pilot contamination. It is assumed that the number of users at the edge of each cell is the same. Therefore, to overcome such limitations of PLUG algorithm, we propose an improved PLUG (IPLUG) algorithm which provides the decision parameters for user grouping and selects the number of central and edge users in each cell in a dynamic manner. Thus, the algorithm prevents the wrong division of users in good channel conditions being considered as an edge user which causes large pilot overhead, and also identifies the users with worst channel conditions and prevents the wrong division of such users from the center user group. The second algorithm for pilot decontamination utilizes the idea of pseudo-random codes in which orthogonal pilot are assigned to different cells. Such codes are deployed to get a transmission pilot by scrambling the user pilot in the cell. Since the pilot contamination is generated because different cells multiplex the same set of orthogonal pilots and the pseudo-random sequences have good cross-correlation characteristics, this paper uses this feature to improve the orthogonality of pilots between different cells. Simulation results show that the proposed algorithms can effectively improve channel estimation performance and achievable rate as compared with other schemes.


Sensors ◽  
2020 ◽  
Vol 20 (12) ◽  
pp. 3361 ◽  
Author(s):  
Shivani Rajendra Teli ◽  
Vicente Matus ◽  
Stanislav Zvanovec ◽  
Rafael Perez-Jimenez ◽  
Stanislav Vitek ◽  
...  

In optical camera communications (OCC), the provision of both flicker-free illumination and high data rates are challenging issues, which can be addressed by utilizing the rolling-shutter (RS) property of the image sensors as the receiver (Rx). In this paper, we propose an RS-based multiple-input multiple-output OCC scheme for the Internet of things (IoT) application. A simplified design of multi-channel transmitter (Tx) using a 7.2 × 7.2 cm2 small 8 × 8 distributed light emitting diode (LED) array, based on grouping of LEDs, is proposed for flicker-free transmission. We carry out an experimental investigation of the indoor OCC system by employing a Raspberry Pi camera as the Rx, with RS capturing mode. Despite the small area of the display, flicker-free communication links within the range of 20–100 cm are established with data throughput of 960 to 120 bps sufficient for IoT. A method to extend link spans up to 1.8 m and the data throughput to 13.44 kbps using different configurations of multi-channel Tx is provided. The peak signal-to-noise ratio of ~14 and 16 dB and the rate of successfully received bits of 99.4 and 81% are measured for the shutter speeds of 200 and 800 µs for a link span of 1 m, respectively.


2021 ◽  
Vol 15 ◽  
pp. 1-10
Author(s):  
Mohammed EL GHZAOUI

Power line communication (PLC) system is an attractive technology for Smart Grid applications. One key benefit of PLC is its low installation cost because, in PLC technology, we do not need to install any extra cable to extend a network due to the accessibility to low voltage power network. Orthogonal frequency division multiplexing (OFDM) is widely used in PLC networks. Currently, Multiple Input Multiple Output (MIMO) technology is one of the processing techniques appropriate to PLC networks, allowing high data rate. In this work, the MIMO-OFDM system is established to provide better performance over the PLC system by providing communication links with substantial diversity and capacity. However, adapting MIMO to the PLC network involves solving several issues such as MIMO PLC channel modelling and optimisation of the modulation parameters. In this paper, we present measurements results of the transfer function and impulsive noise in the extended frequency range 2-100 MHz. In the simulation part, we evaluate the performance of the proposed receivers in 2×2 MIMO-PLC channels. It is shown that the minimum mean square error (MMSE) receiver can be one of the appropriate candidates for MIMO PLC channels due to its bite error rate (BER) characteristics under impulsive noise.


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