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.

Decode-and-Forward vs. Amplify-and-Forward Scheme in Physical Layer Security for Wireless Relay Beamforming Networks

2020 ◽  
Vol 10 (2) ◽  
pp. 9-17
Author(s):  
Tuan Nhu Nguyen
Keyword(s):  
Wireless Networks ◽  
Physical Layer Security ◽  
Secure Communication ◽  
Physical Layer ◽  
Cooperative Relaying ◽  
Transmission Model ◽  
Amplify And Forward ◽  
Decode And Forward ◽  
Encrypt Data ◽  
Cryptographic Algorithms

Abstract— To secure communication from the sender to the receiver in wireless networks, cryptographic algorithms are usually used to encrypt data at the upper layers of a multi-tiered transmission model. Another emerging trend in the security of data transmitted over wireless networks is the physical layer security based on beamforming and interference fading  communication technology and not using cryptographic algorithms. This trend has attracted increasing concerns from both academia and industry. This paper addresses how physical layer security can protect secret data compare with the traditional cryptographic encryption and which is the better cooperative relaying scheme with the state of the art approached methods in wireless relaying beamforming network.Tóm tắt— Việc bảo mật truyền thông vô tuyến từ nơi gửi đến nơi nhận thường sử dụng các thuật toán mật mã để mã hoá dữ liệu tại các tầng phía trên trong mô hình phân lớp. Một xu hướng khác đang được quan tâm rộng rãi là bảo mật tầng vật lý dựa trên kỹ thuật truyền tin beamforming và kỹ thuật tương tác fading kênh chủ động. Xu hướng này hiện đang được thu hút cả trong giới công nghiệp và nghiên cứu. Đóng góp của bài báo này là làm rõ khả năng bảo mật tầng vật lý và so sách chúng với phương pháp bảo mật dùng kỹ thuật mật mã truyền thống. Bài báo cũng so sánh hai kỹ thuật chuyển tiếp được sử dụng chính trong bảo mật tầng vật lý cho mạng vô tuyến chuyển tiếp là Amplify-and-Forward và Decode-and-Forward.

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 Performance Of Full-Duplex One-Way And Two-Way Cooperative Relaying Networks

2018 ◽  
Vol 9 (2) ◽  
pp. 526
Author(s):  
Arunmozhi Sinouvassane ◽  
Nagarajan G
Keyword(s):  
Outage Probability ◽  
Network Coding ◽  
Average Rate ◽  
Arithmetic Function ◽  
Cooperative Relaying ◽  
Full Duplex ◽  
Amplify And Forward ◽  
Decode And Forward ◽  
Time Frequency ◽  
Loop Interference

<p>The wireless research requires concurrent transmission and reception in a single time/frequency channel with good spectral efficiency. The Full duplex system is the alternate for the conventional half duplex systems. An investigation on the need for a full duplex two way (FD-TWR) and one way relaying (FD-OWR) to improve the performance of outage probability and average rate employing amplify-and-forward (AF) and decode-and-forward (DF) protocol is considered. Further the relaying systems performance under the network coding schemes is taken into consideration. The outage probability and average rate of FD-TWR and FD-OWR using a physical layer network coding was performed. In contrast to “straightforward” network coding which performs arithmetic function on digital bit streams after information have been received. The result shows the DF protocol achieves better outage probability and average rate, when compared to the AF protocol. And comparing the full duplex schemes like FD-TWR and FD-OWR, it is found that the FD-TWR achieves better outage probability and average rate, when compared to the FD-OWR. The performance was extended with different loop interference among the relay antennas. The performance show that FD-TWR performs well even in spite of loop interference.<em></em></p><p><em> </em></p>

scholarly journals The Effect of Misdetection Probability on the Performance of Cooperative-Relaying-Based Cognitive Radio Systems

2016 ◽  
Vol 2016 ◽  
pp. 1-10
Author(s):  
Ning Cao ◽  
Yuchang Ye ◽  
Minghe Mao
Keyword(s):  
Cognitive Radio ◽  
Outage Probability ◽  
Power Allocation ◽  
Cooperative Relaying ◽  
Channel Gain ◽  
Practical Implementation ◽  
Amplify And Forward ◽  
Decode And Forward ◽  
Af Relaying ◽  
Allocation Factor

Cognitive radio (CR) is a promising solution to address the more and more congested radio spectrum. Cooperative relaying can provide a better transmission performance for the secondary user (SU), while the performance of the primary user (PU, also named licensed user) should be preferentially protected especially when there is misdetection probability. In this paper, in order to keep the PU away from outage caused by the interference from the SU under a certain signal-to-noise ratio (SNR), the maximum SNR for the SU can be derived by using the rate decaying factor (RDF). Then, based on the maximum channel gain and the maximum SNR, the outage probability is analyzed using decode-and-forward (DF) relaying and amplify-and-forward (AF) relaying schemes. Numerical results show that the outage probability decreases when the power allocation factor increases for DF strategy, while the outage probability has error floor when the power allocation factor increases for AF strategy. And the relaying scheme based on the maximum channel gain outperforms that based on the maximum SNR when the power allocation factor and detection probability are small, while the relaying scheme based on the maximum SNR outperforms that based on the maximum channel gain when the power allocation factor is large. What is more, AF relaying has better outage performance in the practical implementation.

Threshold-based hybrid relay selection and power allocation scheme

2016 ◽  
Vol 8 ◽  
pp. 16
Author(s):  
Xin Song ◽  
MingLei Zhang ◽  
WenMIn Liu ◽  
ShengBao Wang
Keyword(s):  
Outage Probability ◽  
Power Allocation ◽  
Relay Selection ◽  
Cooperative Relaying ◽  
Amplify And Forward ◽  
Decode And Forward ◽  
Opportunistic Relaying ◽  
Transmit Power ◽  
Probability Threshold ◽  
Relaying System

Abstract—To minimize total transmit power in a system while guaranteeing the outage probability at the same time in a cooperative system, we propose and analyse two threshold-based hybrid relay selection and power allocation schemes for a three-node cooperative relaying system. They are designated as: the hybrid amplify-direct-forward relaying (HADF) and incremental hybrid decode-direct-forward relaying (IHDDF) schemes. In the HADF scheme, a specific outage probability threshold is derived to determine that the system chooses to optimize power allocation of its source and relay in amplify-and-forward (AF) mode or optimize the power of its source in direct-transmit (DT) mode without a relay. In IHDDF, according to the outage probability threshold, the system chooses to optimize its power in turn with incremental decode-and-forward opportunistic relaying (IDFO) mode or DT mode. Closed-form expressions of the total transmit power of the proposed HADF and IHDDF schemes are derived. The proposed schemes have low computational complexity and system cost. Theoretical analysis and simulation results show that the HADF scheme outperforms the AF and DT schemes, and the total transmission power of the IHDDF scheme is reduced significantly compared with the IDFO and DT schemes. Compared with the HADF scheme, the IHDDF scheme has a better total transmit power in special channel condition.Keywords—power allocation, three-node cooperative relaying system, amplify-and-forward, incremental decode-and-forward opportunistic relaying.

scholarly journals Capacity and Power Scaling Laws for Finite Antenna MIMO Amplify-and-Forward Relay Networks

2016 ◽  
Vol 62 (4) ◽  
pp. 1993-2008 ◽  
Author(s):  
David E. Simmons ◽  
Justin P. Coon ◽  
Naqueeb Warsi
Keyword(s):  
Scaling Laws ◽  
Relay Networks ◽  
Power Scaling ◽  
Amplify And Forward

scholarly journals Performance Analysis of MIMO STBC System in Flat Fading and Frequency Selective Fading Channels

2019 ◽  
Vol 3 (1) ◽  
pp. 19
Author(s):  
Pebri Yeni Samosir ◽  
Nyoman Pramaita ◽  
I Gst A. Komang Diafari Djuni Hartawan ◽  
Ni Made Ary Esta Dewi Wirastuti
Keyword(s):  
Fading Channels ◽  
System Performance ◽  
Mimo System ◽  
Multipath Fading ◽  
Delay Spread ◽  
Selective Fading ◽  
Frequency Selective Fading ◽  
Flat Fading ◽  
Frequency Selective ◽  
Frequency Selective Fading Channels

Multiple Input Multiple Output (MIMO) technology is a technique that can be used to overcome multipath fading. The multipath fading is caused by signals coming from several paths that experience different attenuations, delays and phases. In a multipath condition, an impulse that sent by the transmitter, will be received by the recipient not as an impulse but as a pulse with a spread width that called delay spread. Delay spread can cause intersymbol interference (ISI) and bit translation errors from the information received. To determine the effect of delay spread on the MIMO system, then MIMO system performance research was performed on flat fading and frequency selective fading channels using the Space Time Block Code (STBC) coding technique. This research was conducted using MatLab 2018a software. The simulation results show that the MIMO STBC system performance on flat fading channels is better than the MIMO STBC system performance on the frequency selective fading channel. This result is analyzed based on the value of BER vs. Eb/No and eye diagram.

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