Relay Channel Model Research Articles

Smart Key

This device is used to operate motorcycle, by multi optional like, manually, through application, Voice Assistant, smartwatch, and whatsapp messages . To make this circuit it requires such as ESP 32, two relay channel models, This device is called SMART-KEY . It is operated through the whatsapp message by sending “key on” and “key off” ,And coming to the application we need to press on off bottons in the app(designed for this smart-key) .And for voice assistance we are using google and Alexa to control the smart-key . And same like application for smartwatch also used to control the smart-key . We should place this device in Scooty or bike This device is secure and Non- Hackable . It is operated through wifi and it’s range unlimited range . We can operate this device with multiple options first one . By using smartphone (application) .Second by using Whatsapp . third by using manual . Forth by using smartwatch . And voice assistant . This mobile application is to access and control the vehicle . It is encrypted device . And this device is said to be embedded system.

Joint Decoder Design for SSDs

Error-correction codes (ECC) and redundant array of independent disks (RAID) are commonly used to protect NAND-based solid state drives (SSD) from serious noise/disturb. In order to tolerate more errors, common solutions are more complex ECCs and RAIDs. Meanwhile, due to the error-correction mechanisms and flash translation layer, NAND-based SSDs inevitably generate abundant redundant information. The theme of this paper is to show that instead of designing new error correction mechanisms from scratch, the NAND-based SSD reliability can be greatly improved by utilizing current decoders to explore the inherent information between redundant pages. We first propose a joint decoder to recover multiple pages by utilizing redundant pages within a stripe of ECC/RAID, and then we consider a joint decoder to recover multiple pages by utilizing write-amplified (WA) pages. The simulation results show that with the proposed algorithm, a performance gain of as much as 1.8 dB can be obtained. The theoretical study reveals that the joint decoding model can be studied from the perspective of relay channel model, and this helps to explore how much information can be reliably stored with the RAID/WA system in SSD.

Hybrid cognitive Gaussian two-way relay channel: Performance analysis and optimal resource allocation

Motivated by the deployment of hybrid cooperative cognitive radio (HCCR) based relays in cellular environments, this paper proposes the hybrid cognitive Gaussian two-way relay channel (HCGTWRC) model. Recently, the combination of licensed and cognitive radios with cooperative systems has gained popularity. These combined techniques have the potential to outperform primary network and pure cognitive network by utilizing the complementary nature of licensed and cognitive radios. In the proposed HCGTWRC model, a relay jointly utilizes both the licensed as well as the unlicensed/cognitive radio resources (RRs). Unlike conventional two-way relay channel, in this proposed model, source uses licensed resources for transmission and relay forwards this information using cognitive RRs. These licensed and unlicensed resources are not affected by total resource constraints of source and relay. Here, unlicensed RRs are not only described by bandwidth and power but also by reliability/availability parameter because of its opportunistic nature. In this paper, the proposed HCGTWRC model is studied by taking information theoretic aspect. In this respect, firstly, upper and lower bounds of performance metrics such as capacity, spectral efficiency (SE), and energy efficiency (EE) are analytically derived for the proposed HCGTWRC model. Then the optimal resource (such as power and bandwidth) allocation is derived with respect to upper and lower bounds of each performance metrics. Further, the performance comparison of the proposed HCGTWRC model is presented with the existing one. Numerical results are also presented for the optimal resource allocation to validate the analytical ones.

Modular Algebraic Precoding Relay System Model Based on Lattice Reduction

According to the existing multi-antenna relay forwarding protocol, the relay matrix can be split into two parts—relay nodes forward and backward filters direct concatenation, then in actual channel matrix design, relay’s forward and backward channel conditions are not ideal, which make system bit error rate (BER) performance is poor. Based on this problem, this paper proposes a modular algebraic precoding relay system model based on lattice reduction. At first, this method re-builds the relay’s forward and backward channel matrices, which can make the channel satisfy the orthogonality characteristics. Then, a modified equivalent relay channel matrix is precoding, which solves tradition algorithms’ poor performance problem when channel orthogonality is not good, and based on this idea, two improved algorithms are proposed. These two new algorithms can achieve better BER performance under poor relay channel conditions, make each user’s performance average, and satisfy system fairness requirements. Simulation results show that comparing with tradition algorithms, this paper proposes a relay channel model which is based on the lattice reduction precoding method, it gains a certain bit error performance. Finally, the improved algorithms are compared and analyzed with the sorting-based algorithm. The results show that the proposed algorithms have better performance. Therefore, in order to ensure users fairness, the optimization algorithm can be used instead of the high complexity sorting-based algorithm in the actual system.

On the Capacity of the Noncausal Relay Channel

This paper studies the noncausal relay channel, also known as the relay channel with unlimited look ahead, introduced by by El Gamal, Hassanpour, and Mammen. Unlike the standard relay channel model, where the relay encodes its signal based on the previous received output symbols, the relay in the noncausal relay channel encodes its signal as a function of the entire received sequence. In the existing coding schemes, the relay uses this noncausal information solely to recover the transmitted message or part of it and then cooperates with the sender to communicate this message to the receiver. However, it is shown in this paper that by applying the Gelfand–Pinsker coding scheme, the relay can take further advantage of the noncausally available information and achieve rates strictly higher than those of the existing coding schemes. This paper also provides a new upper bound on the capacity of the noncausal relay channel that strictly improves upon the existing cutset bound. These new lower and upper bounds on the capacity coincide for the class of degraded noncausal relay channels and establish the capacity for this class.

Capacity of a Class of State-Dependent Orthogonal Relay Channels

The class of orthogonal relay channels in which the orthogonal channels connecting the source terminal to the relay and the destination, and the relay to the destination, depend on a state sequence, is considered. It is assumed that the state sequence is fully known at the destination, while it is not known at the source or the relay. The capacity of this class of relay channels is characterized, and shown to be achieved by the partial decode-compress-and-forward (pDCF) scheme. Then, the capacity of certain binary and Gaussian state-dependent orthogonal relay channels are studied in detail, and it is shown that the compress-and-forward (CF) and partial-decode-and-forward (pDF) schemes are suboptimal in general. To the best of our knowledge, this is the first single relay channel model for which the capacity is achieved by pDCF, while pDF and CF schemes are both suboptimal. Furthermore, it is shown that the capacity of the considered class of state-dependent orthogonal relay channels is in general below the cut-set bound. The conditions under which pDF or CF suffices to meet the cut-set bound, and hence, achieve the capacity, are also derived.

CAO-SIR: Channel Aware Ordered Successive Relaying

Cooperative communication suffers from multiplexing loss and low spectral efficiency due to the half duplex constraint of relays. To improve the multiplexing gain, successive relaying, which allows concurrent transmission of the source and relays, has been proposed. However, the severe inter-relay interference becomes a key challenge. In this paper, we propose a channel aware successive relaying protocol, also referred to as CAO-SIR, which is capable of thoroughly mitigating inter-relay interference by carefully adapting relays' transmission order and rate. In particular, a relay having a poorer link to the source is scheduled first to forward a message, the data rate of which is adapted to the link quality of the source-relay and relay-destination channels. By this means, each relay may decode the messages intended for the preceding relays, and then cancel these relays' interference in a low complexity which is equal to that of Decision Feedback Equalizer (DFE). To further optimize and analyze CAO-SIR, we present its equivalent parallel relay channel model, based upon which the adaptive relay selection and power allocation schemes are proposed. By employing M half duplex relays, CAO-SIR is capable of achieving an diversity-multiplexing tradeoff (DMT) given by d(r) = max (M + 1) 1- {(M+2/M+1r)} , (1 - r) , where d(r) and r denote the diversity and multiplexing gains, respectively. Its DMT asymptotically approaches the DMT upper bound achieved by (M + 1) × 1 MISO systems or M full duplex relays, when M is large.

Research on Physical Layer Network Coding Technology in Wireless Network

Recently, Network coding has been proved to be the breakthrough in the research field of network and communication. It is an effective technique to increase network capacity and improve the robustness and reliability of networks. In this paper, there is application of network coding in wireless network. In order to improve the reliability and the throughput of wireless network, we do extensive research on network coding incorporated with the multicast communication in WLAN, the routing optimization in multi-hop network and the retransmission efficiency for wireless broadcast system, and focus on the protocol design and the theory for the performance analysis. On the basis of introduction on basic idea and method of network coding, we proposes a new physical layer network coding scheme for two-way relay channel model based on a belief propagation approach. Then we make performance analysis through numerical simulation.

Multiple-symbol Differential Sphere Decoding for Network Coding

In order to shorten 3dB performance gap between the conventional differential detection and correlation detection in network coding, we consider multiple-symbol differential detection (MSDD) for two-way relay channel (TWRC) model. MSDD, which makes use of continuously N symbols to jointly detect N-1 symbols. However, the complexity of the maximum likelihood differential detection increases exponentially with the detection group length and the modulation constellation points. In this paper, we propose multiple-symbol differential sphere decoding (MSDSD) to circumvent this excessive computational complexity. Simulation results show that the combination of MSDSD and differential network coding can not only reduce the computational complexity, but also overcome error platform caused by High-Doppler frequency offset at high signal-to-noise ratio, and obtain the optimum detection performance simultaneously. Hence, MSDSD can be regarded as a low complexity detection algorithm in differential network coding scheme. DOI: http://dx.doi.org/10.11591/telkomnika.v11i12.3677 Full Text: PDF

On the Study of Half-Duplex Two-Way Relaying Based on Network Coding

A novel scheme based on detection is proposed for half-duplex two-way relay system in this paper. Multi-input multi-output and network coding technique are applied in the relay. The proposed method employs detection in this system when the relay and two stations receive signal. Theoretical and simulative analyses of the protocol performance under the assumption of a binary symmetric relay channel model are carried out. The zero-forcing detection and maximum likelihood detection are respectively used. The simulation results show that the new scheme facilitates more reliable transmission and higher information transmission rate.

Transmission Scheme of MIMO Two-Way Relaying Systems Based on Symmetric Channel

There are fading and noise in MIMO two-way relaying system. A novel transmission scheme was proposed. The scheme performs equivalent to a 2×2 V-BLAST MIMO(Multiple-Input Multiple-Output) and a two 2×1 AlAMOUTI MISO(Multiple-Input Single-Output) in multiple-access phase and broadcast phase respectively. Network coding and minimum mean square error detection are employed at the relay. Binary phase shift keying and 8 phase shift keying modulation is used. The performance is analyzed under the assumption of a symmetric relay channel model. Simulation results show that the proposed transmission scheme can facilitate more reliable transmission.

Error Rate Analysis of GF(q) Network Coded Detect-and-Forward Wireless Relay Networks Using Equivalent Relay Channel Models

This paper investigates simple means of analyzing the error rate performance of a general q-ary Galois Field network coded detect-and-forward cooperative relay network with known relay error statistics at the destination. Equivalent relay channels are used in obtaining an approximate error rate of the relay network, from which the diversity order is found. Error rate analyses using equivalent relay channel models are shown to be closely matched with simulation results. Using the equivalent relay channels, low complexity receivers are developed whose performances are close to that of the optimal maximum likelihood receiver.

철도 무선통신내에서 협력전송기법의 응용

In recent years, according to improvement of various vehicle instruments, railway also has been developed in various fields. As a result, to transmit accurate information to each railway system, the efficient communication system is required. In railway communication system, mitigation of wireless fading is very important. So, in this paper we introduced the cooperative relay channel model and cooperative relay scheme. Also we analyzed and simulated the cooperative relay scheme which is suitable for railway communication systems.

The value of cooperation between relays in the multiple-access channel with multiple relays

We study the discrete, memoryless multiple-access channel with two independent sources, two relays and a single destination. We refer to this configuration as the multiple- access channel with multiple relays (MACMR), which is a generalization of the multiple-access relay channel (MARC) model obtained by adding a relay node. We present inner and outer bounds on the capacity region of the MACMR. The inner bound is based on a hierarchical decode-and-forward scheme, in which each relay decodes the messages of the lower hierarchy. We extend the regular encoding, sliding-window decoding and backward decoding techniques, previously applied to MARCs and multiple-relay channels, to MACMRs. The outer bounds are obtained using the cut-set bound. For Gaussian MACMRs the bounds are evaluated and compared to those obtained for the multiple-access channel with parallel relays. We conclude that a significant improvement in performance can be obtained by letting the relays interact with each other. Copyright c 0000 John Wiley & Sons, Ltd.

Effect of Impulse Noise on Wireless Relay Channel

Relay Network is most suited wireless communication technique for future Smart Grid, because it has a lot of advantages such as reliability against failures and offers redundancy, self-configuring and self-healing. For example if one nod or path is blocked, it can find a neighbour node, by different algorithms schemes. The purpose of this paper is to simulate wireless relay channel model in presence of impulse noise and computing the BER performance of channel data. It makes to be useful for a designer to predicting error and behaviour of a channel for optimum design, to be able choose a robust channel.

Parity-Check Network Coding for Multiple Access Relay Channel in Wireless Sensor Cooperative Communications

A recently developed theory suggests that network coding is a generalization of source coding and channel coding and thus yields a significant performance improvement in terms of throughput and spatial diversity. This paper proposes a cooperative design of a parity-check network coding scheme in the context of a two-source multiple access relay channel (MARC) model, a common compact model in hierarchical wireless sensor networks (WSNs). The scheme uses Low-Density Parity-Check (LDPC) as the surrogate to build up a layered structure which encapsulates the multiple constituent LDPC codes in the source and relay nodes. Specifically, the relay node decodes the messages from two sources, which are used to generate extra parity-check bits by a random network coding procedure to fill up the rate gap between Source-Relay and Source-Destination transmissions. Then, we derived the key algebraic relationships among multidimensional LDPC constituent codes as one of the constraints for code profile optimization. These extra check bits are sent to the destination to realize a cooperative diversity as well as to approach MARC decode-and-forward (DF) capacity.

A Non-differential Distributed Space-Time Coding for Partially-Coherent Cooperative Communication

In a distributed space-time coding scheme, based on the relay channel model, the relay nodes co-operate to linearly process the transmitted signal from the source and forward them to the destination such that the signal at the destination appears as a space time block code. Recently, a code design criteria for achieving full diversity in a partially-coherent environment have been proposed along with codes based on differential encoding and decoding techniques. For such a set up, in this paper, a nondifferential encoding technique and construction of distributed space time block codes from unitary matrix groups at the source and a set of diagonal unitary matrices for the relays are proposed. It is shown that, the performance of our scheme is independent of the choice of unitary matrices at the relays. When the group is cyclic, a necessary and sufficient condition on the generator of the cyclic group to achieve full diversity and to minimize the pairwise error probability is proved. Various choices on the generator of cyclic group to reduce the ML decoding complexity at the destination is presented. It is also shown that, at the source, if non-cyclic abelian unitary matrix groups are used, then full-diversity can not be obtained. The presented scheme is also robust to failure of any subset of relay nodes.

Gaussian Degraded Relay Broadcast Channel

The relay broadcast channel (RBC) models a system where a transmitter sends information to multiple receivers, aided by the presence of a dedicated relay node. In the Gaussian case with two receivers, under the assumption that both receivers are degraded with respect to the relay, it is shown that the capacity region is achieved by a superposition strategy. This strategy is also shown to be optimal in the case where there is feedback from the receivers to the relay and one receiver assumed to be degraded with respect to the other in an appropriate sense. We also present an achievable region for a more general Gaussian RBC (GRBC) model.

Relay Channel With Private Messages

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> The relay channel with private messages (RCPM) is a generalized relay channel model where in addition to the traditional communication from source to destination (assisted by relay), the source has a private message for the relay, and the relay has a private message for the destination. This paper develops coding strategies for this channel based on decode-and-forward and compress-and-forward schemes. Achievable rate regions as well as outer bounds on the capacity region are obtained for the discrete memoryless relay channel with private messages. Then, the Gaussian versions of this channel are studied and achievable rate regions are characterized. Numerical results are provided that give insights into the trade-offs between private messaging and relayed messaging in this hybrid three-node network. </para>

Low Density Parity Check Codes over Wireless Relay Channels

We exploit the capacity approaching capability of low density parity check (LDPC) codes to design coding schemes for relay channels. We consider the classical relay channel model, and the use of both full-duplex relays and half-duplex ones. In addition to the design of practical coding schemes and the development of the appropriate receiver structures, we also exploit the use of average mutual information to characterize the convergence behavior of the proposed systems. Using the convergence predictions and the simulation results, we demonstrate that the proposed LDPC coded relay systems, in particular, with irregular LDPC codes, have the capability to approach the ergodic/outage information rates very closely. This is true for both ergodic fading channels where the Shannon type (constrained, i.e., modulation specific) capacity is considered, and non-ergodic fading channels where the outage capacity provides the appropriate limits of reliable communication. For the (time-division) half-duplex relay schemes, we also discuss the optimization of the time-division parameters, and the bit allocation strategies to improve the system performance further.