Cognitive Multi-Relay Transmission over Asymmetric Fading Channels with Imperfect CSI

2017 ◽  
Vol 3 (1) ◽  
pp. 46
Author(s):  
Nguyen Hong Giang ◽  
Vo Nguyen Quoc Bao ◽  
Hung Nguyen-Le
Keyword(s):  
Fading Channels ◽  
Rayleigh Fading ◽  
Signal To Noise Ratio ◽  
Rician Fading ◽  
Channel State ◽  
Relay System ◽  
Relay Systems ◽  
Secondary Network ◽  
Secondary Networks ◽  
Good Agreement

Outage performance of a cognitive multi-relay system using imperfect channel state information (CSI) of interfering links is formulated in this paper. In the considered cognitive system, it is assumed that wireless channels in the secondary network (source-to-relay and relay-to-destination links) experience Rician fading whereas interfering channels between primary and secondary networks undergo Rayleigh fading. Under the assumption of asymmetric fading, an outage probability (OP) expression of the secondary network is approximately formulated. Analytical OP values are in good agreement with related empirical ones in low signal-to-noise ratio (SNR) regimes. As a result, the approximate OP expression can be used to quantify the effect of asymmetric fading channels and CSI imperfection on the performance of cognitive multi-relay systems in practical SNR ranges.

scholarly journals Performance Analysis of Hybrid Protocol Based AF EH Relaying over Asymmetric Fading Channels

Information ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 50 ◽  
Author(s):  
Xutao Sheng ◽  
Guangyue Lu ◽  
Liqin Shi ◽  
Yinghui Ye
Keyword(s):  
Fading Channels ◽  
Rayleigh Fading ◽  
Signal To Noise Ratio ◽  
System Capacity ◽  
Rician Fading ◽  
High Signal ◽  
Amplify And Forward ◽  
Relay Nodes ◽  
Energy Constrained ◽  
Selection Of

Simultaneous wireless information and power transfer is a practicable solution to encourage energy-constrained relay nodes to cooperate with the source to transmit information to the destination. In this paper, we study the outage performance of hybrid protocol based amplify-and-forward (AF) relay networks over asymmetric fading channels, where the source-relay link and the relay-destination link are subjected to Rician fading and Rayleigh fading, respectively. In particular, we derive the lower bound of outage probability and the upper bound of outage capacity based on a high signal-to-noise ratio approximation, respectively. We further investigate the effects of various system parameters, such as the parameters of hybrid protocol, the target rate, and the Rician K-factor, on the investigated network. It is shown that a good selection of parameters of hybrid protocol is of significance to improve system capacity, and that a larger Rician factor is desirable in the investigated network.

Effect of CSI Imperfection on Cognitive Underlay Transmission over Nakagami-m Fading Channel

2015 ◽  
Vol 1 ◽  
pp. 59
Author(s):  
Nguyen Hong Giang ◽  
Vo Nguyen Quoc Bao ◽  
Hung Nguyen-Le
Keyword(s):  
Fading Channels ◽  
System Performance ◽  
Performance Metrics ◽  
Maximal Ratio Combining ◽  
Relay Nodes ◽  
Channel State ◽  
Primary Network ◽  
Secondary Network ◽  
System Designs ◽  
Approximate Expressions

This paper analyzes the performance of a cognitive underlay system over Nakagami-m fading channels, where maximal ratio combining (MRC) is employed at secondary destination and relay nodes. Under the condition of imperfect channel state information (CSI) of interfering channels, system performance metrics for the primary network and for the secondary network are formulated into exact and approximate expressions, which can be served as theoretical guidelines for system designs. To verify the performance analysis, several analytical and simulated results of the system performance are provided under various system and channel settings.

scholarly journals MIMO Self-Encoded Spread Spectrum with Iterative Detection over Rayleigh Fading Channels

2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Shichuan Ma ◽  
Lim Nguyen ◽  
Won Mee Jang ◽  
Yaoqing (Lamar) Yang
Keyword(s):  
Fading Channels ◽  
Spread Spectrum ◽  
Rayleigh Fading ◽  
Mimo Systems ◽  
Signal To Noise Ratio ◽  
Multiple Input Multiple Output ◽  
Spatial Diversity ◽  
Iterative Detection ◽  
Channel Fading ◽  
Input Multiple Output

Self-encoded spread spectrum (SESS) is a novel communication technique that derives its spreading code from the randomness of the source stream rather than using conventional pseudorandom noise (PN) code. In this paper, we propose to incorporate SESS in multiple-input multiple-output (MIMO) systems as a means to combat against fading effects in wireless channels. Orthogonal space-time block-coded MIMO technique is employed to achieve spatial diversity, and the inherent temporal diversity in SESS modulation is exploited with iterative detection. Simulation results demonstrate that MIMO-SESS can effectively mitigate the channel fading effect such that the system can achieve a bit error rate of with very low signal-to-noise ratio, from 3.3 dB for a antenna configuration to just less than 0 dB for a configuration under Rayleigh fading. The performance improvement for the case is as much as 6.7 dB when compared to an MIMO PN-coded spread spectrum system.

scholarly journals Outage Performance Improvement by Selected User in D2D Transmission and Implementation of Cognitive Radio-Assisted NOMA

Sensors ◽  
2019 ◽  
Vol 19 (22) ◽  
pp. 4840
Author(s):  
Dinh-Thuan Do ◽  
Minh-Sang Van Nguyen ◽  
Byung Moo Lee
Keyword(s):  
Cognitive Radio ◽  
Fading Channels ◽  
Interference Cancellation ◽  
Rayleigh Fading ◽  
Positive Impact ◽  
System Model ◽  
Outage Performance ◽  
Secondary Network ◽  
Asymptotic Expressions ◽  
D2d Transmission

In this paper, we investigate the outage performance in secondary network of cognitive radio (CR) employing non-orthogonal multiple access (NOMA) wireless networks over Rayleigh fading channels. The considered system model adopts device-to-device (D2D) transmission together with traditional communication to form a new system model, namely CR-D2DNOMA network. The specific user is selected from multiple D2D-Tx users (D2Ds) to communicate with far NOMA users to form qualified D2D connection with assistance of the Relay user ( R U ). The main metric in such CR-D2DNOMA network needs to be considered and we particularly introduce the closed-form expressions for outage probability in the secondary network where it is designed to serve two far NOMA users. The perfect Successive Interference Cancellation (SIC) and imperfect SIC can be further examined at the second NOMA user who detects signal based on the ability of SIC. The results show the positive impact of increasing the fading parameters on the system performance. More importantly, numerical results are provided to verify the correctness of our derivations. Additionally, the effects of asymptotic expressions on insights evaluation are also further analyzed.

scholarly journals Exact Performance Analysis of Amplify-and-Forward Bidirectional Relaying over Nakagami-m Fading Channels with Arbitrary Parameters

Energies ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1277
Author(s):  
Dong Qin ◽  
Yuhao Wang ◽  
Tianqing Zhou
Keyword(s):  
Fading Channels ◽  
Signal To Noise Ratio ◽  
Ergodic Capacity ◽  
Moment Generating Function ◽  
Amplify And Forward ◽  
Relay Systems ◽  
Signal Error ◽  
Bidirectional Relaying ◽  
Fading Parameter ◽  
The Moment

The exact performance of amplify-and-forward (AF) bidirectional relay systems is studied in generalized and versatile Nakagami-m fading channels, where the parameter m is an arbitrary positive number. We consider three relaying modes: two, three, and four time slot bidirectional relaying. Closed form expressions of the moment generating function (MGF), higher order moments of signal-to-noise ratio (SNR), ergodic capacity, and average signal error probability (SEP) are derived, which are different from previous works. The obtained expressions are very concise, easy to calculate, and evaluated instantaneously without a complex summation operation, in contrast to the nested multifold numerical integrals and truncated infinite series expansions used in previous work, which lead to computational inefficiency, especially when the fading parameter m increases. Simulation results corroborate the correctness and tightness of the theoretical analysis.

Sign in / Sign up

Export Citation Format

Share Document