A Double Data Rate, Low Complexity 2 x 2 MIMO Scheme Based on a Combination of Alamouti System and Orthogonal Codes

2013 ◽  
pp. 310-318
Author(s):  
Nizar Ouni ◽  
Ridha Bouallegue
Keyword(s):  
Low Complexity ◽  
Data Rate ◽  
Orthogonal Codes

Coherent Passive Backscatter Communications Using Ambient Transmitters

2014 ◽  
Vol 5 (2) ◽  
pp. 23-43
Author(s):  
William C. Barott ◽  
Kevin M. Scott
Keyword(s):  
Radio Frequency ◽  
Low Complexity ◽  
Data Rate ◽  
Experimental Results ◽  
Digital Television ◽  
Passive Radar ◽  
Detection Range ◽  
Backscatter Modulation ◽  
Radio Frequency Signals ◽  
Processing Algorithms

A communications method is presented based on the backscatter modulation of incident radio frequency signals using low-complexity tags. The incident signals arise from digital television stations used as illuminators of opportunity. A receiver detects the tag using coherent processing algorithms similar to those used in passive radar, extending the detection range over published noncoherent techniques. This method enables shared use of the UHF television band for low-data-rate applications. While analyses suggest that rates exceeding 1 kbps might be achievable at 1 km range, experimental results demonstrate the challenges in designing and implementing such a system.

scholarly journals Wi-Fi Backscatter System with Tag Sensors Using Multi-Antennas for Increased Data Rate and Reliability

Sensors ◽  
2020 ◽  
Vol 20 (5) ◽  
pp. 1314
Author(s):  
Taeoh Kim ◽  
Hyobeen Park ◽  
Yunho Jung ◽  
Seongjoo Lee
Keyword(s):  
Computational Complexity ◽  
Euclidean Distance ◽  
Multiple Antennas ◽  
Power Level ◽  
Low Complexity ◽  
Data Rate ◽  
Threshold Method ◽  
Channel State ◽  
Distance Method ◽  
Ber Performance

In this paper, we propose tag sensor using multi-antennas in a Wi-Fi backscatter system, which results in an improved data rate or reliability of the signal transmitted from a tag sensor to a reader. The existing power level modulation method, which is proposed to improve data rate in a Wi-Fi backscatter system, has low reliability due to the reduced distance between symbols. To address this problem, we propose a Wi-Fi backscatter system that obtains channel diversity by applying multiple antennas. Two backscatter methods are described for improving the data rate or reliability in the proposed system. In addition, we propose three low complexity demodulation methods to address the high computational complexity problem caused by multiple antennas: (1) SET (subcarrier energy-based threshold) method, (2) TCST (tag’s channel state-based threshold) method, and (3) SED (similar Euclidean distance) method. In order to verify the performance of the proposed backscatter method and low complexity demodulation schemes, the 802.11 TGn (task group n) channel model was utilized in simulation. In this paper, the proposed tag sensor structure was compared with existing methods using only sub-channels with a large difference in received CSI (channel state information) values or adopting power-level modulation. The proposed scheme showed about 10 dB better bit error rate (BER) performance and throughput. Also, proposed low complexity demodulation schemes were similar in BER performance with a difference of up to 1 dB and the computational complexity was reduced by up to 60% compared to the existing Euclidean distance method.

scholarly journals PAPR Reduction in MIMO-OFDM Systems Using Low- Complexity Additive Signal Mixing

2021 ◽  
pp. 468-478
Author(s):  
Stephen Kiambi ◽  
◽  
Elijah Mwangi ◽  
George Kamucha
Keyword(s):  
Communication Systems ◽  
Window Size ◽  
Low Complexity ◽  
Data Rate ◽  
Papr Reduction ◽  
Ofdm Systems ◽  
High Data ◽  
Communication Technique ◽  
Mimo Ofdm ◽  
Ber Performance

A MIMO-OFDM wireless communication technique possesses several advantages accrued from combining MIMO and OFDM techniques such as increased channel capacity and improved BER performance. This has made the technique very amiable to current and future generations of communication systems for high data-rate transmission. However, the technique also inherits the high PAPR problem associated with OFDM signals—a problem still requiring a practical solution. This work proposes a PAPR reduction algorithm for solving the problem of high PAPR in MIMO-OFDM systems. The proposed method uses a low-complexity signal mixing concept to combine the original transmit signal and a generated peak-cancelling signal. The computational complexity of the proposed method is O(M) , which is very much less than O(N log2 N) of the FFT algorithms. This is because M, which denotes the number of nonzero peakcancelling samples, is much less than N, the FFT window size. The proposed method was found to achieve high PAPR reductions while utilizing only a few nonzero peak-cancelling samples and it does not significantly change the power of the transmitted signal. For example, with M=5% of 256-point IFFT samples, corresponding to a data rate loss of 4.8%, a large PAPR reduction of 5.9 dB could be achieved at a small power loss of 0.09 dB. Compared with other methods proposed in literature, the proposed method was found to outperform them in terms of PAPR reductions and BER performance.

scholarly journals Natural Brain-Inspired Intelligence for Non-Gaussian and Nonlinear Environments with Finite Memory

2020 ◽  
Vol 10 (3) ◽  
pp. 1150
Author(s):  
Mahdi Naghshvarianjahromi ◽  
Shiva Kumar ◽  
M. Jamal Deen
Keyword(s):  
Decision Making ◽  
Orthogonal Frequency Division Multiplexing ◽  
Low Complexity ◽  
Data Rate ◽  
Smart Systems ◽  
Current State ◽  
Cognitive Decision ◽  
Non Gaussian ◽  
Conventional Systems

The cyber processing layer of smart systems based on a cognitive dynamic system (CDS) can be a good solution for better decision making and situation understanding in non-Gaussian and nonlinear environments (NGNLE). The NGNLE situation understanding means deciding between certain known situations in NGNLE to understand the current state condition. Here, we report on a cognitive decision-making (CDM) system inspired by the human brain decision-making. The simple low-complexity algorithmic design of the proposed CDM system can make it suitable for real-time applications. A case study of the implementation of the CDS on a long-haul fiber-optic orthogonal frequency division multiplexing (OFDM) link was performed. An improvement in Q-factor of ~7 dB and an enhancement in data rate efficiency ~43% were achieved using the proposed algorithms. Furthermore, an extra 20% data rate enhancement was obtained by guaranteeing to keep the CDM error automatically under the system threshold. The proposed system can be extended as a general software-based platform for brain-inspired decision making in smart systems in the presence of nonlinearity and non-Gaussian characteristics. Therefore, it can easily upgrade the conventional systems to a smart one for autonomic CDM applications.

A Study on Smart Agricultural Facilities Wireless Networking

2014 ◽  
Vol 926-930 ◽  
pp. 2213-2216
Author(s):  
Zhen Gang Yao
Keyword(s):  
Wireless Communication ◽  
Low Power ◽  
Communication Technology ◽  
Network Topology ◽  
Short Distance ◽  
Low Complexity ◽  
Wireless Networking ◽  
Data Rate ◽  
Power Cost ◽  
Zigbee Network

A wireless networking method for smart agricultural facilities was proposed in this paper. As ZigBee was a short distance, low complexity, low power cost, low data rate and two-way wireless communication technology, the wireless networking method was based on ZigBee. Network topology, hardware and software were designed in the paper.

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