scholarly journals Qualitative analysis for coverage probability and energy efficiency in cognitive-femtocell networks under macrocell infrastructure

Author(s):  
Joydev Ghosh

<div>The network coverage and energy efficiency issues in heterogeneous cognitive-femtocell networks over the macrocell network is studied. Cognitive functions in wireless network nodes are serviceable with the macrocell infrastructure to achieve a balance between two desirable</div><div>but incompatible features: coverage and energy efficiency. There are two basic but related aspects of cognitive radios (CRs) in the context of wireless communications: optimum CRs for energy efficiency and the act of the functioning of CRs with energy efficiency. To fully utilise the cognitive capability, a dual-tier network architecture is assumed where both the macrocell and the femtocell have a bearing</div><div>on the cognitive capability. Owing to the salient features of femtocells, they can improve the coverage and enhance the spectrum efficiency by reutilising the frequency spectrum allocated to the macrocell, although, the resulting intercell interference accompanied by the same frequency coverage cannot be underestimated. The effectiveness of the scheme is verified by extensive Matlab simulation.</div>

2021 ◽  
Author(s):  
Joydev Ghosh

<div>The network coverage and energy efficiency issues in heterogeneous cognitive-femtocell networks over the macrocell network is studied. Cognitive functions in wireless network nodes are serviceable with the macrocell infrastructure to achieve a balance between two desirable</div><div>but incompatible features: coverage and energy efficiency. There are two basic but related aspects of cognitive radios (CRs) in the context of wireless communications: optimum CRs for energy efficiency and the act of the functioning of CRs with energy efficiency. To fully utilise the cognitive capability, a dual-tier network architecture is assumed where both the macrocell and the femtocell have a bearing</div><div>on the cognitive capability. Owing to the salient features of femtocells, they can improve the coverage and enhance the spectrum efficiency by reutilising the frequency spectrum allocated to the macrocell, although, the resulting intercell interference accompanied by the same frequency coverage cannot be underestimated. The effectiveness of the scheme is verified by extensive Matlab simulation.</div>


2021 ◽  
Author(s):  
Joydev Ghosh

<div>In this paper, we initially dealt with the issue of spectrum allocation among macro (or “licensed”) and Femto (or “unlicensed”) users in an Orthogonal Frequency Devision Multiple Access (OFDMA) based dual-layer femtocell networks. This research contribution will lead to basic coin in the design of next generation (5G) wireless networks. This manuscript exemplifies the trade off issue of energy efficiency (EE) and spectral efficiency (SE) with both cooperative and non-cooperative architecture in cognitive femtocell networks. The pivotal concepts for each technology are described, along with their potential impact on 5G and the research challenges that remain. Further, the trade-off between EE and SE is reposed with respect to the state of the art. The obtained insightful observations from the trade-off analysis of EE ans SE can lead to provide design guideline for 5G wireless Networks.</div>


2021 ◽  
Author(s):  
Joydev Ghosh

<div>In this paper, we initially dealt with the issue of spectrum allocation among macro (or “licensed”) and Femto (or “unlicensed”) users in an Orthogonal Frequency Devision Multiple Access (OFDMA) based dual-layer femtocell networks. This research contribution will lead to basic coin in the design of next generation (5G) wireless networks. This manuscript exemplifies the trade off issue of energy efficiency (EE) and spectral efficiency (SE) with both cooperative and non-cooperative architecture in cognitive femtocell networks. The pivotal concepts for each technology are described, along with their potential impact on 5G and the research challenges that remain. Further, the trade-off between EE and SE is reposed with respect to the state of the art. The obtained insightful observations from the trade-off analysis of EE ans SE can lead to provide design guideline for 5G wireless Networks.</div>


Author(s):  
Hoang Nhu Dong ◽  
Hoang Nam Nguyen ◽  
Hoang Trong Minh ◽  
Takahiko Saba

Femtocell networks have been proposed for indoor communications as the extension of cellular networks for enhancing coverage performance. Because femtocells have small coverage radius, typically from 15 to 30 meters, a femtocell user (FU) walking at low speed can still make several femtocell-to-femtocell handovers during its connection. When performing a femtocell-to-femtocell handover, femtocell selection used to select the target handover femtocell has to be able not only to reduce unnecessary handovers and but also to support FU’s quality of service (QoS). In the paper, we propose a femtocell selection scheme for femtocell-tofemtocell handover, named Mobility Prediction and Capacity Estimation based scheme (MPCE-based scheme), which has the advantages of the mobility prediction and femtocell’s available capacity estimation methods. Performance results obtained by computer simulation show that the proposed MPCE-based scheme can reduce unnecessary femtocell-tofemtocell handovers, maintain low data delay and improve the throughput of femtocell users. DOI: 10.32913/rd-ict.vol3.no14.536


2021 ◽  
Vol 11 (2) ◽  
pp. 716
Author(s):  
Ruibiao Chen ◽  
Fangxing Shu ◽  
Kai Lei ◽  
Jianping Wang ◽  
Liangjie Zhang

Non-orthogonal multiple access (NOMA) has been considered a promising technique for the fifth generation (5G) mobile communication networks because of its high spectrum efficiency. In NOMA, by using successive interference cancellation (SIC) techniques at the receivers, multiple users with different channel gain can be multiplexed together in the same subchannel for concurrent transmission in the same spectrum. The simultaneously multiple transmission achieves high system throughput in NOMA. However, it also leads to more energy consumption, limiting its application in many energy-constrained scenarios. As a result, the enhancement of energy efficiency becomes a critical issue in NOMA systems. This paper focuses on efficient user clustering strategy and power allocation design of downlink NOMA systems. The energy efficiency maximization of downlink NOMA systems is formulated as an NP-hard optimization problem under maximum transmission power, minimum data transmission rate requirement, and SIC requirement. For the approximate solution with much lower complexity, we first exploit a quick suboptimal clustering method to assign each user to a subchannel. Given the user clustering result, the optimal power allocation problem is solved in two steps. By employing the Lagrangian multiplier method with Karush–Kuhn–Tucker optimality conditions, the optimal power allocation is calculated for each subchannel. In addition, then, an inter-cluster dynamic programming model is further developed to achieve the overall maximum energy efficiency. The theoretical analysis and simulations show that the proposed schemes achieve a significant energy efficiency gain compared with existing methods.


Author(s):  
Xiuhua Fu ◽  
Tian Ding ◽  
Rongqun Peng ◽  
Cong Liu ◽  
Mohamed Cheriet

AbstractThis paper studies the communication problem between UAVs and cellular base stations in a 5G IoT scenario where multiple UAVs work together. We are dedicated to the uplink channel modeling and the performance analysis of the uplink transmission. In the channel model, we consider the impact of 3D distance and multi-UAVs reflection on wireless signal propagation. The 3D distance is used to calculate the path loss, which can better reflect the actual path loss. The power control factor is used to adjust the UAV's uplink transmit power to compensate for different propagation path losses, so as to achieve precise power control. This paper proposes a binary exponential power control algorithm suitable for 5G networked UAV transmitters and presents the entire power control process including the open-loop phase and the closed-loop phase. The effects of power control factors on coverage probability, spectrum efficiency and energy efficiency under different 3D distances are simulated and analyzed. The results show that the optimal power control factor can be found from the point of view of energy efficiency.


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