Performance analysis of selective decode and forward protocol with partner selection

In wireless communication, Multiple Input Multiple Output (MIMO) technology has proven to improve reliability through spatial diversity. Cooperative relay transmission is an emerging concept, which involves the users to share their resources to improve overall system performance. In this work, Selective Decode and Forward (SDF) cooperative relaying scheme is analyzed. This paper describes power optimization in relay nodes for a dual hop half-duplex SDF based cooperative relay communication system, with nodes using multiple antenna. For the proposed system model, average end-to-end probability of error is derived, leading to evaluation of asymptotically tight upper bound under high signal to noise ratio. Optimal power allocation to minimize the bit error rate (BER) is formulated and a closed form solution for this convex optimization problem is derived and verified through simulation. The BER performance of the system is compared with that of cooperative relay network having single antenna at the participating nodes. Results show sharp decline in error rate with increase in the number of participating antenna. Simulation results reveal that cooperate scheme with optimal power allocation has an improved performance, compared to its direct link counterpart.

Consider a multi-relay cooperative diversity network consisting of a source, N relays, and a destination. For the transmission of a data symbol from the source to the destination, the relays cooperate with the source through the decode and forward protocol. All the links are statistically independent and undergo flat Rayleigh fading. Conventional instantaneous signal-to-noise ratio based selection combining at the destination chooses one link from the set consisting of the source-to-destination link and the N relay-to-destination links. However, this scheme does not account for the effect of the source-to-relay links in the error performance. To overcome this drawback, we present here a scaled selection combining scheme, which accounts for this effect through a deterministic scale factor. The end-to-end symbol error probability (SEP) of this scheme with binary phase-shift keying is derived in closed form. We also give a method of obtaining the optimum scale factor that minimizes the end-to-end SEP.

This paper compares the energy consumption of non-cooperative schemes and the Selective Decode and Forward (SDF) cooperative protocol in Wireless Sensor Networks. This Analysis was performed over Nakagami-m channel, under Outage probability and system end-to-end throughput constraints. Under these constraint, we assume that in multi-hop and cooperative schemes scenarios, the nodes operate at a spectral efficiency L greater than that of the single-hop. As the energy consumption of the RF circuitry cannot be neglected, it is noteworthy that cooperation may be considerably more energy efficient than non-cooperative schemes even in small range distance. We study then the effect of pathloss component and the target outage probability in the energy consumption.

A cooperative diversity system improves the communication reliability and throughput in a multipath fading environment with the help of relay nodes. We consider a cooperative diversity system with a source (S), a decode-and-forward relay (R), and a selection-combining-enabled destination (D). In this paper, we derive the exact end-to-end symbol error probability (SEP) for $M$ -ary phase-shift keying (MPSK) signaling using a paired error approach and differential binary phase-shift keying (DBPSK) signaling over correlated, nonidentical, slow, and flat Nakagami- $m$ fading channels by assuming the correlation between SD–RD, SR–SD, and SR–RD fading channels. In addition, we perform the exact outage probability analysis for the same scenario. Furthermore, we provide the asymptotic expressions for SEP and outage probability by removing the infinite-series terms to investigate the diversity order. In a nutshell, the numerical results reveal that the SR–RD correlated channel scenario outperforms the uncorrelated channel scenario in terms of SEP. In addition, SEP performance degradation is observed in the case of other correlated channel scenarios compared with the uncorrelated channel scenario. Moreover, marginal performance improvement in outage probability is observed in the low-signal-to-noise-ratio (SNR) regime of the SR–RD correlated channel scenario compared with the uncorrelated channel scenario. Finally, Monte Carlo simulations are performed to validate the theoretical results.

An intelligent reflecting surface (IRS) assisted wireless communication system, with statistically correlated channels between the transmitter and the IRS pair and between the IRS and the receiver pair, is studied in the absence of channel state information (CSI). Assuming the phases added by IRS elements to be deterministic, the closed-form analytical expression for the symbol error probability (SEP) and the upper bound on the channel capacity are derived, with the transmitter employing binary phase-shift keying (BPSK) modulation for data transmission. The asymptotic SEP expression is derived and the achievable diversity order of the system is shown to be independent of the number of IRS elements. A search based algorithm is proposed to obtain the optimal phase at IRS minimizing the average SEP, as a equal phase configuration. The optimal equal phase is also found to maximize the average channel capacity. Numerical results are presented for the case of channels following a practical IRS correlation model.

Multi-hop cooperative MIMO network that consists of multiple nodes each equipped with single antenna is introduced and investigated. Optimal power allocation scheme with selective decode-and-forward (SDF) cooperative strategy is formulated and solved by means of optimization method with the purpose of minimization of system’s symbol error rate (SER), which are derived and analyzed with numerical results presented. Distributed space-time block Code (DSTBC) in multi-hop cooperative MIMO is analyzed and compared with optimal power allocation scheme with SDF strategy. Simulation results reveal that, cooperative diversity could be achieved with optimal power allocation. Optimum power allocation scheme depends on the relay’s position and channel quality between source to relay and relay to destination. Novel performance comparison between optimal power allocation and DSTBC are researched and presented. Simulation results confirm our theoretical analysis, which indicates that multi-node DSTBC outperforms optimal power allocation scheme due to the fact that cooperative diversity gain and coded gain could be obtained simultaneously for DSTBC in multi-hop cooperative MIMO network.

In this work, we explore the outage probability (OP) analysis of selective decode and forward (S-DF) cooperation protocol employing multiple-input multiple-output (MIMO) orthogonal space-time block-code (OSTBC) over time varying Rayleigh fading channel conditions with imperfect channel state information (CSI) and mobile nodes. The closed-form expressions of the per-block average OP, probability distribution function (PDF) of sum of independent and identically distributed (i.i.d.) Gamma random variables (RVs), and cumulative distribution function (CDF) are derived and used to investigate the performance of the relaying network. A mathematical framework is developed to derive the optimal source-relay power allocation factors. It is shown that source node mobility affects the per-block average OP performance more significantly than the destination node mobility. Nevertheless, in other node mobility situations, cooperative systems are constrained by an error floor with a higher signal to noise ratio (SNR) regimes. Simulation results show that the equal power allocation is the only possible optimal solution when source to relay link is stronger than the relay to destination link. Also, we allocate almost all the power to the source node when source to relay link is weaker than the relay to destination link. Simulation results also show that OP simulated plots are in close agreement with the OP analytic plots at high SNR regimes.

We consider a cooperative diversity system comprising of a source, a decode and forward (DF) relay and a destination. The performance of the decode and forward (DF) protocol in a cooperative diversity system depends solely on the accuracy of decoding of the symbols at the relay. In this work, we pine to improve the accuracy of the decoding process and in-turn the performance of the cooperative diversity system by introducing erasure regions in the decoding process at the relay. The erasure regions are designed in such a way that if the received signal lies in any of these regions then, the relay does not participate in the cooperation. At the destination, a modified selection combining scheme known as scaled selection combining (SSC) is employed. A theoretical expression for the end-to-end symbol error probability of an M-ary PSK modulation in a Rayleigh fading environment is derived based on the paired error approach invoking the idea of the erasure regions. Simulation results substantiated with theoretical results elucidate that the cooperative diversity system with erasure significantly outperforms the system without erasure.

In this paper, we investigate the benefit of Joint Network Channel Coding (JNCC) for a new class of Multiple Access Relay Channel (MARC), defined as follows: (1) Independent sources communicate with a single destination in the presence of a relay; (2) The relay is half-duplex and applies a Selective Decode and Forward (SDF) strategy, i.e, it forwards only a deterministic function of the error-free decoded messages; (3) The sources are allowed to transmit simultaneously during both the listening phase and the transmission phase of the relay. We refer this model to as Non-Orthogonal MARC (NOMARC), which better leverages the broadcast nature of the radio channel than its more conservative orthogonal counterpart, i.e., Orthogonal MARC (OMARC). This paper aims at measuring the advantage brought by NOMARC/JNCC over OMARC/JNCC from both an information-theoretic and a practical code design perspectives.

In this paper, we investigate the benefit of Joint Network Channel Coding (JNCC) for a new class of Multiple Access Relay Channel (MARC), defined as follows: (1) Independent sources communicate with a single destination in the presence of a relay; (2) The relay is half-duplex and applies a Selective Decode and Forward (SDF) strategy, i.e, it forwards only a deterministic function of the error-free decoded messages; (3) The sources are allowed to transmit simultaneously during the listening phase of the relay, but are constrained to remain silent during its transmission phase. We refer this model to as Semi-Orthogonal MARC (SOMARC), which leverages better the broadcast nature of the radio channel than its more conservative orthogonal counterpart, referred to as Orthogonal MARC (OMARC). All links are subject to slow fading and additive white Gaussian noise. This paper aims at measuring the advantage brought by the SOMARC over OMARC from both an information-theoretic and a practical code design perspective.

In this paper, two novel adaptive spatial scattering modulation (ASSM) algorithms, namely unequal transmission probability-based ASSM (UTP-ASSM) and equal transmission probability-based ASSM (ETP-ASSM), are proposed to pursue a better tradeoff between the computational complexity and spectral efficiency. According to available channel state information, the proposed ASSM algorithms are conducted to compute the optimal numbers of scatters and the optimal modulation orders constrained by the maximal tolerable symbol error probability (SEP). In addition, the minimal tolerate value of the minimal tolerant signal-to-noise ratio and SEP threshold are computed with a given data rate requirement by the bisection algorithm. At the receiver, a new type of optimal maximum likelihood detector is proposed to enhance the SEP performance. Furthermore, the union upper bound on the SEP is derived and analyzed. In addition, the computational complexity and system performance of the ASSM schemes are analyzed. Simulation results demonstrate that the proposed ASSM algorithms yield a lower SEP than the conventional spatial scattering modulation at the same value of average data rate.

This paper proposes a novel optimal receiver for an $N$ -branch receive diversity power line communication (PLC) system subject to Rayleigh fading and perturbed by Nakagami-m background noise. A Gauss-optimal receiver is obtained from the optimal receiver which is further utilized to derive a closed form expression for the symbol error probability (SEP) for binary phase-shift keying (BPSK) modulation using a characteristic function approach under the condition that mN is an integer. An asymptotic expression for the SEP at high signal-to-noise ratio (SNR) shows the diversity order of the PLC system to be independent of the noise shape parameter $m$ . Numerical studies demonstrate that the diversity order of the optimal receiver is preserved with the suboptimal receiver as well. Furthermore, the advantage of using multiple receive branches in terms of achieving better error performance and the effect of the shape parameter $m$ on the SEP of the suboptimal receiver are also presented.

Aiming at efficient utilizing the licensed spectrum, in this paper, we develop an interference cancellation based transmission strategy (ICTS) for the cooperative cognitive radio networks (CRN) which will take advantage of the opportunities that arise during the primary automatic repeat requests (ARQ) and cancel the primary interference in both the primary initial transmission and retransmission slots. Simultaneously, the secondary system will cooperate with the primary system by supporting its outage quality-of-service (QoS) requirement to speedup the primary transmission and acquire more interference-free spectrum opportunities. Specifically, in the primary initial transmission slot, the secondary users (SU) will transmit in the underlay mode. In addition, SUs try to decode the primary signal to cancel the primary interference and overhear the primary ARQ signal. In the retransmission slot, SUs can cancel the primary interference directly when the primary signal is successfully decoded in the initial slot or utilize the primary information redundancy to cancel the interference. With statistical channel state information (CSI), SUs can calculate their interference cancellation probabilities in both slots and derive their average transmission rate. To maximize SUs' average transmission rate while meeting PUs outage QoS requirement, we formulate the optimization problem and efficiently allocate SUs transmit power. The closed-form expressions of the average transmission rates for both PUs and SUs are derived. Furthermore, SUs' upper bound symbol error probability (SEP) and PUs' SEP are derived. Simulation results demonstrate the performance superiority of our developed ICTS over conventional ARQ-based transmission strategies in terms of SUs' average throughput and PUs' outage probability and SEP.

We develop a protocol that permits effective use of differential space-time coding schemes for cooperative diversity systems. The consideration of system design without assuming the knowledge of channel state information (CSI) at the receiver becomes therefore more realistic. With the use of the proposed protocol, it is shown that the use of differential space-time codes in space-time cooperation is feasible with the performance degraded only by 3 dB noise enhancement compared with the coherent detection. The performance of the cooperative diversity system is analyzed for a two-user case for different channel environments in terms of the diversity gain and the diversity product. The optimization of the power allocation between source and relay terminals is considered for the maximization of the diversity product.

Full-duplex amplify-and-forward relay system with direct link: Performance analysis and optimization