New multiple-input multiple-output-based filter bank multicarrier structure for cognitive radio networks

2019 ◽  
Vol 13 (10) ◽  
pp. 1514-1523
Author(s):  
Zahraa Abd El-Hamid ◽  
Emad S. Hassan ◽  
Abdel-Halim A. Zekry ◽  
Salah S. Elagooz ◽  
Moataz Samir ◽  
...  
2011 ◽  
Vol 1 (1) ◽  
Author(s):  
Maurice Bellanger

The challenge of opportunistic networks is to maximize the usage of the spectrum by offering quick and easy access to independent systems and their users. A physical layer able to operate efficiently in an unsynchronized environment is needed and it is shown that the filter bank multicarrier (FBMC) technique can meet the objectives in terms of performance and flexibility. Then, a protocol must be developed to ensure global convergence and an overall transmission capacity close to the optimal possible value at a given place and a given time. An approach called “good neighbour” is presented, which consists of building the capacity requested by the users through a threshold regulated local search and with minimum changes in frequency band allocation to reduce interference non-stationarity to other systems. Finally, potential applications of opportunistic networks are reviewed and the conditions for proliferation of this kind of network are discussed.


2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Jun Sun ◽  
Xiaomin Mu ◽  
Dejin Kong ◽  
Qian Wang ◽  
Xinmin Li ◽  
...  

In filter bank multicarrier with offset quadrature amplitude modulation (FBMC/OQAM) systems, a large pilot overhead is required due to the existence of the imaginary interference. In this paper, we present an approach to reduce the pilot overhead of channel estimation. A part of pilot overhead is used for transmitting data, and compensating symbols are required and designed to remove the imaginary interference. It is worthwhile to point out that the power of compensating symbols can be helpful for data recovery; hence, the proposed approach decreases the overhead of pilots significantly without the cost of additional pilot energy. In addition, the proposed scheme is extended into multiple input multiple output systems without the performance loss. Compared with the conventional preamble consisting of 3 columns symbols, the pilot overhead is equivalent to 2 column symbols in the proposed preamble. To verify the proposed preamble, numerical simulations are carried out with respects to bit error ratio.


Frequenz ◽  
2015 ◽  
Vol 69 (3-4) ◽  
Author(s):  
M. Mazoochi ◽  
M. A. Pourmina ◽  
H. Bakhshi

AbstractThe core aim of this work is the maximization of the achievable data rate of the secondary user pairs (SU pairs), while ensuring the QoS of primary users (PUs). All users are assumed to be equipped with multiple antennas. It is assumed that when PUs are present, the direct communications between SU pairs introduces intolerable interference to PUs and thereby SUs transmit signal using the cooperation of other SUs and avoid transmitting in the direct channel. In brief, an adaptive cooperative strategy for multiple-input/multiple-output (MIMO) cognitive radio networks is proposed. At the presence of PUs, the issue of joint relay selection and power allocation in Underlay MIMO Cooperative Cognitive Radio Networks (U-MIMO-CCRN) is addressed. The optimal approach for determining the power allocation and the cooperating SU is proposed. Besides, the outage probability of the proposed communication protocol is further derived. Due to high complexity of the optimal approach, a low-complexity approach is further proposed and its performance is evaluated using simulations. The simulation results reveal that the performance loss due to the low-complexity approach is only about 14%, while the complexity is greatly reduced.


Author(s):  
V. Annapoorani ◽  
S. Sureshkumar ◽  
Srisaravanapathimurugesan ◽  
M. Manoj ◽  
K. Prabhu

The networks in future generation uses the confluence of multi-media, broadband, and broadcast services, Cognitive Radio (CR) networks are located as a preferred paradigm to bring up with spectrum functionality traumatic conditions. CRS addresses the ones troubles via dynamic spectrum access. However, the precept traumatic conditions faced through manner of manner of the CR pertain to accomplishing spectrum overall performance. At the end, spectrum overall performance improvement models based on spectrum sensing and sharing models have attracted quite a few research hobby in modern-day years, which incorporates CR mastering models, network densification architectures, and Massive Multiple Input Multiple Output (MIMO), and beamforming techniques. This paper deals with a survey of modern CR spectrum overall improvement performance models and techniques which helps ultra-high reliability with low latency communications which might be resilient to surges in web page site visitors and competition for spectrum. These models and techniques, mainly speaks about permit a big form of functionality beginning from extra superb mobiliary broadband to large-scale Internet of Things (IoT) type communications. It also provides a research correlation for many of the regular periods of a spectrum block, as well as the realistic statistics rate, the models which are used in this paper are applicable in an ultra-high frequency band. This study provides a super compare of CRs and direction for future investigations into newly identified 5G research areas, such as in business enterprise and academia.


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