A Comparative Experimental Study of MIMO A&F and D&F Relay Nodes Using a Software-Defined Radio Platform

Abstract

The relaying technologies in co-operative systems are considered a core element in actual and future wireless communications, assisting the network by enhancing its reliability and improving its capability through exploiting co-operativity. In this paper, a co-operative system testbed based on Software Defined Radio (SDR) through Universal Software Radio Peripherals (USRPs) and the MATLABTM software is presented. The main novelty in this development of the platform is the implementation of 4G signal features, such as Physical Downlink Shared Channel (PDSCH) and Downlink Shared Channel (DL-SCH) for transport channel coding, which is one of the main contribution of the paper. The developed SDR Multi-Input and Multi-Output (MIMO) co-operative platform is capable of developing prototypes for the Relay Nodes (RNs). More specifically, the Amplify-&-Forward (A&F)—with or without Zero Forcing (ZF) and Mean Maximum Square Error (MMSE) Pre-Equalization—and Decode-&-Forward (D&F) protocols were implemented. Both Single-Input and Single-Output (SISO) and MIMO modes are supported by our testbed. The developed A&F and D&F MIMO co-operative systems in this paper utilize Orthogonal Space-Frequency Block Codes (OSFBCs) for the transmission of data symbols from the source to the destination. Our results show that RNs can substantially improve the Bit Error Rate (BER) and throughput in communications between the eNodeB and User Equipment (UE). In particular, the maximum throughput achieved by conventional MIMO A&F is 9.3Mbps at Signal-to-NoiseRatio(SNR)=16dB, which is 4Mbps higher than throughput of MIMO Non-Co-operative. It also shows the capacity improvement when considering the pre-equalization in the A&F schemes, compared to the conventional A&F RN. For example, with MIMO A&F-MMSE pattern, a value os 11.8 Mbps is achieved for SNR=16dB, which is 84.8% of the maximum system throughput (13.95 Mbps). On the other hand, the obtained results with D&F schemes far exceed those obtained with A&F strategies, achieving the maximum performance with the 2×2 MIMO D&F protocol from SNR=8dB.Furthermore, this work constitutes a first stage to the implementation of a 5G New-Radio Co-operative System platform.

Design and Synchronization Procedures of a D&F Co-Operative 5G Network Based on SDR Hardware Interface: Performance Analysis

“…The results obtained in previously published works [29,[36][37][38][39] are consistent with those obtained in this paper, demonstrating the improvements that the use of D&F relay nodes introduces in the performance of the network. Table 2 shows a comparative summary of the experimental results obtained in this paper.…”

“…Our software defined radio platform and Matlab TM tool for co-operative LTE network was designed and explained in [29,32]. However, to implement the decode-and-forward cooperative network, the 5G system has been upgraded from the hardware interface, which will allow approaching research in the future of the out-of-band D&F node in the mmWave frequency band.…”

“…Our investigation team has been designing and implementing wireless communication network through the software defined radio platform and Matlab TM software. Particularly, we have been deeply studying, designing, and implementing the relay node co-operative network over the downlink LTE signal [29]. Recently, refs.…”

Experimental real-time GbE MIMO FSO under fog conditions with software defined GNU Radio platform-based adaptive switching

“…It is worth mentioning that software defined radio (SDR)-based platforms have been known to provide flexibility and reconfigurability in practical implementation and evaluation of adaptive techniques in MIMO FSO systems. Additionally, SDR, which is designed to remove hardware limitations, offers many advantages including (i) implementation of signal processing through the physical and medium access control layers [17], (ii) software-configurability and control, (iii) improved system performance with the efficient and flexible use of the RF spectrum for new services to the end users, (iv) a reduced system size and minimization of the design risk and time-to-market, and (v) flexibility in research and development due to the implementation and verification of a range of newly developed protocols [18]. The experimental implementation of SDRbased RF systems utilizing universal software radio peripheral (USRP) were reported in [19][20][21].…”

Performance Analysis of Two-Hop mmWave Relay Nodes over the 5G NR Uplink Signal

“…Our investigation team has been deeply studying the co-operative networks in this context; in [17], a MIMO relay node co-operative system based on Software Defined Radio (SDR) and Matlab TM software is implemented over the downlink LTE signal. Additionally, ref.…”