scholarly journals Multiple Access-Enabled Relaying with Piece-Wise and Forward NOMA: Rate Optimization under Reliability Constraints

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4783
Author(s):  
Farnaz Khodakhah ◽  
Aamir Mahmood ◽  
Patrik Österberg ◽  
Mikael Gidlund
Keyword(s):  
Spectrum Sharing ◽  
Multiple Access ◽  
Cooperative Relaying ◽  
Achievable Rate ◽  
Second Phase ◽  
Relay Channel ◽  
Direct Link ◽  
Secondary System ◽  
Amplify And Forward ◽  
Decode And Forward

The increasing proliferation of Internet-of-things (IoT) networks in a given space requires exploring various communication solutions (e.g., cooperative relaying, non-orthogonal multiple access, spectrum sharing) jointly to increase the performance of coexisting IoT systems. However, the design complexity of such a system increases, especially under the constraints of performance targets. In this respect, this paper studies multiple-access enabled relaying by a lower-priority secondary system, which cooperatively relays the incoming information to the primary users and simultaneously transmits its own data. We consider that the direct link between the primary transmitter–receiver pair uses orthogonal multiple access in the first phase. In the second phase, a secondary transmitter adopts a relaying strategy to support the direct link while it uses non-orthogonal multiple access (NOMA) to serve the secondary receiver. As a relaying scheme, we propose a piece-wise and forward (PF) relay protocol, which, depending on the absolute value of the received primary signal, acts similar to decode-and-forward (DF) and amplify-and-forward (AF) schemes in high and low signal-to-noise ratio (SNR), respectively. By doing so, PF achieves the best of these two relaying protocols using the adaptive threshold according to the transmitter-relay channel condition. Under PF-NOMA, first, we find the achievable rate region for primary and secondary receivers, and then we formulate an optimization problem to derive the optimal PF-NOMA time and power fraction that maximize the secondary rate subject to reliability constraints on both the primary and the secondary links. Our simulation results and analysis show that the PF-NOMA outperforms DF-NOMA and AF-NOMA-based relaying techniques in terms of achievable rate regions and rate-guaranteed relay locations.

scholarly journals Hybrid AF/DF Cooperative Relaying Technique with Phase Steering for Industrial IoT Networks

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 937
Author(s):  
Sangku Lee ◽  
Janghyuk Youn ◽  
Bang Chul Jung
Keyword(s):  
Spectrum Sharing ◽  
Low Cost ◽  
Relay Node ◽  
Access Point ◽  
Radio Spectrum ◽  
Cooperative Relaying ◽  
Amplify And Forward ◽  
Relay Nodes ◽  
Decode And Forward ◽  
Industrial Iot

For the next generation of manufacturing, the industrial internet of things (IoT) has been considered as a key technology that enables smart factories, in which sensors transfer measured data, actuators are controlled, and systems are connected wirelessly. In particular, the wireless sensor network (WSN) needs to operate with low cost, low power (energy), and narrow spectrum, which are the most technical challenges for industrial IoT networks. In general, a relay-assisted communication network has been known to overcome scarce energy problems, and a spectrum-sharing technique has been considered as a promising technique for the radio spectrum shortage problem. In this paper, we propose a phase steering based hybrid cooperative relaying (PSHCR) technique for the generic relay-assisted spectrum-shared WSN, which consists of a secondary transmitter, multiple secondary relays (SRs), a secondary access point, and multiple primary access points. Basically, SRs in the proposed PSHCR technique operate with decode-and-forward (DF) relaying protocol, but it does not abandon the SRs that failed in decoding at the first hop. Instead, the SRs operate with amplify-and-forward (AF) protocol when they failed in decoding at the first hop. Furthermore, the SRs (regardless of operating with AF or DF protocol) that satisfy interference constraints to the primary network are allowed to transmit a signal to the secondary access point at the second hop. Note that phase distortion is compensated through phase steering operation at each relay node before second-hop transmission, and thus all relay nodes can operate in a fully distributed manner. Finally, we validate that the proposed PSHCR technique significantly outperforms the existing best single relay selection (BSR) technique and cooperative phase steering (CPS) technique in terms of outage performance via extensive computer simulations.

scholarly journals Outage Analysis in SWIPT Enabled Spectrum Sharing D2D Communication for IoT Applications

2021 ◽  
Author(s):  
Sutanu Ghosh ◽  
Tamaghna Acharya ◽  
Santi P. Maity
Keyword(s):  
Network Architecture ◽  
Spectrum Sharing ◽  
Spectrum Efficiency ◽  
Design Parameters ◽  
Secondary System ◽  
D2d Communications ◽  
Amplify And Forward ◽  
Decode And Forward ◽  
The Impact ◽  
Af Relaying

<div>This paper reports a relative performance analysis of decode-and-forward (DF) and amplify-and-forward (AF) relaying in a multi-antenna cooperative cognitive radio network (CCRN) that supports device-to-device (D2D) communications using spectrum sharing technique in cellular network. In this work, cellular system is considered as primary and internet of things devices (IoDs), engaged in D2D communications, are considered as secondary system. The devices access the licensed spectrum by means of the cooperation in two-way primary communications. Furthermore, IoDs are energized through the harvesting of energy from radio frequency (RF) signals, using simultaneous wireless information and power transfer (SWIPT) protocol. Closed form expressions of the outage probability for both cellular and D2D communications are derived and the impact of various design parameters for both AF and DF relaying techniques are studied. Based on the simulation results, it is found that the proposed spectrum sharing protocol, for both DF relaying and AF relaying schemes, outperform a similar network architecture in terms of spectrum efficiency. It is also observed that the performance of the proposed system using DF relaying is ~168% better compared to AF relaying scheme in term of peak energy efficiency at same transmit power.</div>

scholarly journals Outage Analysis in SWIPT Enabled Cooperative AF/DF Relay Assisted Two-Way Spectrum Sharing Communication

2021 ◽  
Author(s):  
Sutanu Ghosh ◽  
Tamaghna Acharya ◽  
Santi P. Maity
Keyword(s):  
Network Architecture ◽  
Spectrum Sharing ◽  
Spectrum Efficiency ◽  
Design Parameters ◽  
Secondary System ◽  
D2d Communications ◽  
Amplify And Forward ◽  
Decode And Forward ◽  
The Impact ◽  
Af Relaying

<pre>This paper reports relative performance of decode-and-forward (DF) and amplify-and-forward (AF) relaying in a multi-antenna cooperative cognitive radio network (CCRN) that supports device-to-device (D2D) communications using spectrum sharing technique in cellular network. In this work, cellular system is considered as primary and internet of things devices (IoDs), engaged in D2D communications, are considered to be secondary system. The devices access the licensed spectrum by means of the cooperation in two-way primary communications. Furthermore, IoDs are energized by harvesting the energy from radio frequency (RF) signals, using simultaneous wireless information and power transfer (SWIPT) protocol. Closed form expressions of outage probability for both cellular and D2D communications are derived and the impact of various design parameters for both AF and DF relaying techniques are studied. Based on the simulation results, it is found that the proposed spectrum sharing protocol, for both DF relaying and AF relaying schemes, outperform another similar network architecture in terms of spectrum efficiency. It is also observed that the performance of the proposed system using DF relaying is better than AF relaying scheme in terms of energy efficiency at same transmit power<br></pre>

scholarly journals Outage Analysis in SWIPT Enabled Spectrum Sharing D2D Communication for IoT Applications

2021 ◽  
Author(s):  
Sutanu Ghosh ◽  
Tamaghna Acharya ◽  
Santi P. Maity
Keyword(s):  
Network Architecture ◽  
Spectrum Sharing ◽  
Spectrum Efficiency ◽  
Design Parameters ◽  
Secondary System ◽  
D2d Communications ◽  
Amplify And Forward ◽  
Decode And Forward ◽  
The Impact ◽  
Af Relaying

<div>This paper reports a relative performance analysis of decode-and-forward (DF) and amplify-and-forward (AF) relaying in a multi-antenna cooperative cognitive radio network (CCRN) that supports device-to-device (D2D) communications using spectrum sharing technique in cellular network. In this work, cellular system is considered as primary and internet of things devices (IoDs), engaged in D2D communications, are considered as secondary system. The devices access the licensed spectrum by means of the cooperation in two-way primary communications. Furthermore, IoDs are energized through the harvesting of energy from radio frequency (RF) signals, using simultaneous wireless information and power transfer (SWIPT) protocol. Closed form expressions of the outage probability for both cellular and D2D communications are derived and the impact of various design parameters for both AF and DF relaying techniques are studied. Based on the simulation results, it is found that the proposed spectrum sharing protocol, for both DF relaying and AF relaying schemes, outperform a similar network architecture in terms of spectrum efficiency. It is also observed that the performance of the proposed system using DF relaying is ~168% better compared to AF relaying scheme in term of peak energy efficiency at same transmit power.</div>

scholarly journals Evaluation of PLC Channel Capacity and ABER Performances for OFDM-Based Two-Hop Relaying Transmission

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Sana Ezzine ◽  
Fatma Abdelkefi ◽  
Jean Pierre Cances ◽  
Vahid Meghdadi ◽  
Ammar Bouallégue
Keyword(s):  
Channel Capacity ◽  
Orthogonal Frequency Division Multiplexing ◽  
Low Cost ◽  
Relay Node ◽  
Destination Node ◽  
Direct Link ◽  
Amplify And Forward ◽  
Decode And Forward ◽  
Maximum Ratio Combining ◽  
The Impact

Powerline network is recognized as a favorable infrastructure for Smart Grid to transmit information in the network thanks to its broad coverage and low cost deployment. The existing works are trying to improve and adapt transmission techniques to reduce Powerline Communication (PLC) channel attenuation and exploit the limited bandwidth to support high data rate over long distances. Two-hop relaying BroadBand PLC (BB-PLC) system, in which Orthogonal Frequency Division Multiplexing (OFDM) is used, is considered in this paper. We derive and compare the PLC channel capacity and the end-to-end Average BER (ABER) for OFDM-based direct link (DL) BB-PLC system and for OFDM-based two-hop relaying BB-PLC system for Amplify and Forward (AF) and Decode and Forward (DF) protocols. We analyze the improvements when we consider the direct link in a cooperative communication when the relay node only transmits the correctly decoded signal. Maximum ratio combining is employed at the destination node to detect the transmitted signal. In addition, in this paper, we highlight the impact of the relay location on the channel capacity and ABER for AF and DF transmission protocols. Moreover, an efficient use of the direct link was also investigated in this paper.

scholarly journals A Coordinated Direct AF/DF Relay-Aided NOMA Framework for Low Outage

2021 ◽  
Author(s):  
Anand Jee ◽  
KAMAL AGRAWAL ◽  
Shankar Prakriya
Keyword(s):  
Energy Efficiency ◽  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Outage Probability ◽  
Closed Form ◽  
Power Allocation ◽  
Multiple Access ◽  
Performance Gain ◽  
Amplify And Forward ◽  
Decode And Forward

This paper investigates the performance of a framework for low-outage downlink non-orthogonal multiple access (NOMA) signalling using a coordinated direct and relay transmission (CDRT) scheme with direct links to both the near-user (NU) and the far-user (FU). Both amplify-and-forward (AF) and decode-and-forward (DF) relaying are considered. In this framework, NU and FU combine the signals from BS and R to attain good outage performance and harness a diversity of two without any need for feedback. For the NU, this serves as an incentive to participate in NOMA signalling. For both NU and FU, expressions for outage probability and throughput are derived in closed form. High-SNR approximations to the outage probability are also presented. We demonstrate that the choice of power allocation coefficient and target rate is crucial to maximize the NU performance while ensuring a desired FU performance. We demonstrate performance gain of the proposed scheme over selective decode-and-forward (SDF) CDRT-NOMA in terms of three metrics: outage probability, sum throughput and energy efficiency. Further, we demonstrate that by choosing the target rate intelligently, the proposed CDRT NOMA scheme ensures higher energy efficiency (EE) in comparison to its orthogonal multiple access counterpart. Monte Carlo simulations validate the derived expressions.

scholarly journals Performance Enhancement for Multihop Cognitive DF and AF Relaying Protocols under Joint Impact of Interference and Hardware Noises: NOMA for Primary Network and Best-Path Selection for Secondary Network

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Tran Trung Duy ◽  
Pham Thi Dan Ngoc ◽  
Phuong T. Tran
Keyword(s):  
Spectrum Sharing ◽  
Performance Enhancement ◽  
Path Selection ◽  
Secondary Source ◽  
Amplify And Forward ◽  
Decode And Forward ◽  
Transmit Power ◽  
Primary Network ◽  
Secondary Network ◽  
Relaying Protocols

In this paper, we propose and evaluate performance of multihop multipath underlay cognitive radio networks. In a primary network, an uplink nonorthogonal multiple access method is employed to allow primary transmitters to simultaneously transmit their data to a primary receiver. Using an underlay spectrum-sharing method, secondary source and secondary relays must adjust their transmit power to guarantee quality of service of the primary network. Under the limited transmit power, cochannel interference from the primary transmitters, and hardware noises caused by impairments, we propose best-path selection methods to improve the end-to-end performance for the secondary network. Moreover, both multihop decode-and-forward and amplify-and-forward relaying protocols are considered in this paper. We derive expressions of outage probability for the primary and secondary networks and propose an efficient method to calculate the transmit power of the secondary transmitters. Then, computer simulations employing the Monte-Carlo approach are realized to validate the derivations.

scholarly journals LOS-Based Equal Gain Transmission and Combining in General Frequency-Selective Ricean Massive MIMO Channels

Electronics ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 79 ◽  
Author(s):  
Qiuna Yan ◽  
Yu Sun ◽  
Dian-Wu Yue
Keyword(s):  
Spatial Correlation ◽  
Scaling Laws ◽  
Mimo System ◽  
Cooperative Relaying ◽  
Power Scaling ◽  
Hardware Complexity ◽  
Amplify And Forward ◽  
Decode And Forward ◽  
Frequency Selective ◽  
General Frequency

In general frequency-selective Ricean fading environments with doubly-ended spatial correlation, this paper investigates the spectral efficiency of a broadband massive multiple-input multiple-output (MIMO) system. In particular, in order to reduce overhead of channel estimation effectively, it proposes a scheme of equal gain transmission and combining, which is only based on line- of-sight (LOS) component and has low hardware complexity. With the scheme, several interesting transmit power scaling properties without and with spatial correlation are derived when the number of antennas at the transmitter or the number of antennas at the receiver grows in an unlimited way. Furthermore, the asymptotical rate analysis is extended to the cooperative relaying scenarios with decode-and-forward and amplify-and-forward protocols, respectively, and then two novel power scaling laws are given.

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