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 Secrecy Performance of TAS/SC-Based Multi-Hop Harvest-to-Transmit Cognitive WSNs Under Joint Constraint of Interference and Hardware Imperfection

Sensors ◽  
2019 ◽  
Vol 19 (5) ◽  
pp. 1160 ◽  
Author(s):  
Phu Tin ◽  
Pham Minh Nam ◽  
Tran Trung Duy ◽  
Phuong Tran ◽  
Miroslav Voznak
Keyword(s):  
Antenna Selection ◽  
Selection Combining ◽  
Secrecy Outage Probability ◽  
Transmit Antenna Selection ◽  
Transmit Power ◽  
Primary Network ◽  
Secondary Network ◽  
Asymptotic Expressions ◽  
Radio Frequency Signals ◽  
Secrecy Outage

In this paper, we evaluate the secrecy performance of multi-hop cognitive wireless sensor networks (WSNs). In the secondary network, a source transmits its data to a destination via the multi-hop relaying model using the transmit antenna selection (TAS)/selection combining (SC) technique at each hop, in the presence of an eavesdropper who wants to receive the data illegally. The secondary transmitters, including the source and intermediate relays, have to harvest energy from radio-frequency signals of a power beacon for transmitting the source data. Moreover, their transmit power must be adjusted to satisfy the quality of service (QoS) of the primary network. Under the joint impact of hardware imperfection and interference constraint, expressions for the transmit power for the secondary transmitters are derived. We also derive exact and asymptotic expressions of secrecy outage probability (SOP) and probability of non-zero secrecy capacity (PNSC) for the proposed protocol over Rayleigh fading channel. The derivations are then verified by Monte Carlo simulations.

scholarly journals Auction-Based Secondary Relay Selection on Overlay Spectrum Sharing in Hybrid Satellite–Terrestrial Sensor Networks

Sensors ◽  
2019 ◽  
Vol 19 (22) ◽  
pp. 5039
Author(s):  
Xiaokai Zhang ◽  
Bangning Zhang ◽  
Kang An ◽  
Zhuyun Chen ◽  
Daoxing Guo
Keyword(s):  
Sensor Networks ◽  
Spectrum Sharing ◽  
Relay Selection ◽  
Amplify And Forward ◽  
Decode And Forward ◽  
Auction Mechanism ◽  
Network Information ◽  
Incomplete Network Information ◽  
Time Division ◽  
Secondary Networks

In this paper, we investigate the auction-based secondary relay selection on overlay spectrum sharing in hybrid satellite–terrestrial sensor networks (HSTSNs), where both the decode-and-forward (DF) and amplify-and-forward (AF) relay protocols are analyzed based on time division multiple access (TDMA). As both the primary and secondary networks are rational, honest but with incomplete network information, they prefer to obtain maximum possibility payoffs by the cooperation between the primary and secondary networks, and the competition among secondary networks. Hence, Vickery auction is introduced to achieve the effective and efficient secondary relay selection by distinct sub-time slot allocation for one shot in terms of a distributed manner. Finally, numerical simulations are provided to validate the effectiveness of the auction mechanism on cooperative spectrum sharing in HSTSNs for secondary relay selection. Besides, the effect of key factors on the performance of the auction mechanism are analyzed in details.

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 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 The Optimal Power Allocation with Hybrid Relaying Based on Channel Condition

2018 ◽  
Author(s):  
Junpyo Jeon ◽  
Yeonggyu Shim ◽  
Hyuncheol Park
Keyword(s):  
Power Allocation ◽  
Relay Network ◽  
Achievable Rate ◽  
Optimal Power Allocation ◽  
Allocation Scheme ◽  
Amplify And Forward ◽  
Decode And Forward ◽  
Transmit Power ◽  
Optimal Power ◽  
Af Relay

This paper considers a hybrid relay network consisting of the source, the amplify-and-forward (AF) relay, the decode-and-forward (DF) relay, and the destination. We propose the optimal power allocation schemes between two different relays which maximize the achievable rate under a sum relay power constraint for given channel gains and transmit power from source. By solving the optimization problem to maximize the achievable rate for each relay network, the transmit power values in closed-form are derived. When the channel gains are the same, the optimal power allocation scheme for AF-DF relay network proves that a more power should be allocated at the first relay to maximize the achievable rate. In case of the DF-AF relay network, we derive the optimal power allocation scheme for the possible four cases. Under the same SNR condition at the first hop, we show that the achievable rate of AF-DF relay network is greater than that of DF-AF relay network when the channel gain between two relays is higher than that between the second relay and destination. Simulation results show that the proposed power allocation schemes provide a higher achievable rate than the equal power allocation schemes.

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 Interference Alignment in Multi-Hop Cognitive Radio Networks under Interference Leakage

2018 ◽  
Vol 8 (12) ◽  
pp. 2486 ◽  
Author(s):  
Eylem Erdogan ◽  
Sultan Çolak ◽  
Hakan Alakoca ◽  
Mustafa Namdar ◽  
Arif Basgumus ◽  
...  
Keyword(s):  
Cognitive Radio ◽  
Interference Alignment ◽  
Ergodic Capacity ◽  
Secondary Source ◽  
Primary Network ◽  
Secondary Network ◽  
The Impact ◽  
Secondary Networks ◽  
Diversity Gains ◽  
Multiple Primary Users

In this work, we examine the interference alignment (IA) performance of a multi-input multi-output (MIMO) multi-hop cognitive radio (CR) network in the presence of multiple primary users. In the proposed architecture, it is assumed that linear IA is adopted at the secondary network to alleviate the interference between primary and secondary networks. By doing so, the secondary source can communicate with the secondary destination via multiple relays without causing any interference to the primary network. Even though linear IA can suppress the interference in CR networks considerably, interference leakages may occur due to a fast fading channel. To this end, we focus on the performance of the secondary network for two different cases: (i) the interference is perfectly aligned; (ii) the impact of interference leakages. For both cases, closed-form expressions of outage probability and ergodic capacity are derived. The results, which are validated by Monte Carlo simulations, show that interference leakages can deteriorate both system performance and the diversity gains considerably.

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 Joint resource optimization in spectrum sharing decode and forward relaying networks

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0251509
Author(s):  
Dong Qin
Keyword(s):  
Cognitive Radio ◽  
Communication Networks ◽  
Cognitive Radio Networks ◽  
Orthogonal Frequency Division Multiplexing ◽  
Spectrum Sharing ◽  
Primary User ◽  
Radio Networks ◽  
Decode And Forward ◽  
Secondary Network ◽  
Sum Rate

This paper proposes an adaptive power allocation and subcarrier pairing algorithm for orthogonal frequency division multiplexing based decode and forward cognitive radio networks, where primary and secondary users achieve spectrum sharing in the same frequency band. The secondary network tries to maximize its sum rate while ensuring that the interference introduced to the primary network is below an acceptable level. Although similar problems have been investigated in traditional cooperative communication networks, it’s still an open issue in cognitive radio networks due to interference thresholds. The power consumed by the secondary network is not only limited by its own power peak, but also by the interference threshold of the primary user. Our proposed algorithm not only allocates power and pairs subcarriers reasonably, but also specifies the conditions under which the relaying link is superior to the direct transmission. Simulation results show that the sum rate of the proposed algorithm exceeds other methods and obtains a significant performance gain.

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