Probabilistic Cooperative Coded Forwarding for Broadcast Transmissions in Industrial Mobile Edge Communications

Mobile edge computing (MEC) has been considered as a key enabler for the industrial internet of things (IIoT) to cope with the ever-increasing communication and computing demands of nodes. In consideration of the limited power and resource of the IIoT nodes, it is necessary to design cost-effective data sharing mechanisms for MEC-enabled wireless industrial communication networks. In this article, we propose the probabilistic cooperative coded forwarding (PCCF) scheme based on network coding (NC) to minimize the required transmission number in both the data source and relay nodes. The data packets are encoded sparsely in a systematic coding framework so that the decoding process at the receivers can be more efficient. The relationship between the forwarding and coding parameters of the proposed scheme and the successful decoding probability are comprehensively analyzed and the approximations are numerically verified. Throughout the analysis, we find the optimal sparsity of network coding vectors and also the existence of minimum transmission numbers.

Performance Metrics for Bluetooth Scatternet Scheduling Using Relays

While various ad hoc mobile wireless networks are already accessible, Bluetooth is one of the most up-to-date. A single-hop connection known as piconet is a simple Bluetooth communication architecture, allowing for just eight functioning electronic equipment, seven of which are operational slaves under a single master. A common hub called a relay links a huge network named Scatternet to a number of piconets. The efficacy of Scatternet design is clearly intrinsically connected to the effectiveness of relay nodes. Because every relay has several piconet transactions to process and manage, a reduction in the number of switches might lead to poor performance instead. The major aim of this research is to examine performance characteristics which impact interplay since the role of the base station is to multiple piconet transitions. In this study, we evaluate and respond to the technical issues that must be optimally solved the Scatternet data flow based on the relay node. Keywords: Bluetooth, Piconet, Scatternet, Relay Node

Secure Physical Layer Network Coding versus Secure Network Coding

When a network has relay nodes, there is a risk that a part of the information is leaked to an untrusted relay. Secure network coding (secure NC) is known as a method to resolve this problem, which enables the secrecy of the message when the message is transmitted over a noiseless network and a part of the edges or a part of the intermediate (untrusted) nodes are eavesdropped. If the channels on the network are noisy, the error correction is applied to noisy channels before the application of secure NC on an upper layer. In contrast, secure physical layer network coding (secure PLNC) is a method to securely transmit a message by a combination of coding operation on nodes when the network is composed of set of noisy channels. Since secure NC is a protocol on an upper layer, secure PLNC can be considered as a cross-layer protocol. In this paper, we compare secure PLNC with a simple combination of secure NC and error correction over several typical network models studied in secure NC.

Relay-Based Clustering Method for Interference Management in Heterogeneous Wireless Cellular Network

Femtocell is one of solutions to improve quality of services and network capacity for users in indoor areas. Radio resources used by femtocells are shared from macrocell network, thus it saves the use of frequency spectrum. However, one of problems in deploying femtocells within coverage area of macrocells is interference due to radio resources sharing between femtocells and macrocells. It creates interferences called as cross-tier (macrocell-femtocell/femtocell-macrocell) and co-tier (macrocell-macrocell/femtocell-femtocell) interferences. This paper proposes a relay-based clustering method to mitigate interference in femtocells located in the whole edge area of macrocell and the cell edge area of sectorized macrocells. Relay nodes are deployed statically (fixed location) in the neighboring macrocell area. Relay node will recruit their members based on the shortest distance. Certain relay node’s members do not need to transmit large amounts of power to enhanced Node B (eNB), such that interference from Macrocell User Equipment (MUE) to Home enhanced Node B (HeNB) can be minimized. Simulation experiments has been carried out and optimistic results for the sectorized macrocells scenario show that Signal-to-Interference-plus-Noise-Ratio (SINR) of femtocells for the conventional system that does not reach the targeted SINR of 20 dB is 87%. Meanwhile, after applying the relay-based clustering method, SINR value of femtocells below or equal to 20 dB reaches 72%. Optimistic results for throughput and Bit Error Rate (BER) show improvement of 15% and 14%, respectively. It has been shown that the relay-based clustering method can provide better performance compared to the conventional system even for femtocells densely deployed.

An Efficent Coverage and Maximization of Network Lifetime in WSN Through Metaheuristics

<span>In wireless sensor networks (WSNs), energy, connectivity, and coverage are the three most important constraints for guaranteed data forwarding from every sensor node to the base station. Due to continuous sensing and transmission tasks, the sensor nodes deplete more quickly and hence they seek the help of data forwarding nodes, called relay nodes. However, for a given set of sensor nodes, finding optimal locations to place relay nodes is a very challenging problem. Moreover, from the earlier studies, the relay node placement is defined as a non-deterministic polynomial tree hard (NP-Hard) problem. To solve this problem, we propose a multi-objective firefly algorithm-based relay node placement (MOFF-RNP) to deploy an optimal number of relay nodes while considering connectivity, coverage, and energy constraints. To achieve network lifetime, this work adopted energy harvesting capabilities to the sensor nodes and backup relay strategy such that every sensor node is always connected to at least one relay to forward the data. The optimal relay placement is formulated as an objective function and MOFF is applied to achieve a better solution. Extensive Simulations are carried out over the proposed model to validate the performance and the obtained results are compared with state-of-art methods)</span>

An Analytical Model for Multihop LoRaWAN Networks

LoRaWAN is one of the most popular LPWAN technology due to the facility to implement applications that require a low cost, low energy consumption, low data rate, and large coverage area. A LoRaWAN network is composed of end-devices that transmit data to gateways, forming a single-hop star topology. Multihop networks are receiving the attention of the LoRaWAN community since it allows to extend the coverage area and improve the energy efficiency,<br>thus prolonging the network lifetime. In this paper, we propose an analytical model for multihop LoRaWAN networks.<br>We investigate the energy consumption, throughput, delay, and packet delivery ratio of single-hop and multihop relay<br>networks. The results showed that the network performance could be improved with relay nodes, giving insights to new<br>multihop proposals for LoRaWAN.

An Analytical Model for Multihop LoRaWAN Networks

LoRaWAN is one of the most popular LPWAN technology due to the facility to implement applications that require a low cost, low energy consumption, low data rate, and large coverage area. A LoRaWAN network is composed of end-devices that transmit data to gateways, forming a single-hop star topology. Multihop networks are receiving the attention of the LoRaWAN community since it allows to extend the coverage area and improve the energy efficiency,<br>thus prolonging the network lifetime. In this paper, we propose an analytical model for multihop LoRaWAN networks.<br>We investigate the energy consumption, throughput, delay, and packet delivery ratio of single-hop and multihop relay<br>networks. The results showed that the network performance could be improved with relay nodes, giving insights to new<br>multihop proposals for LoRaWAN.

ACTS: An Ant Colony Based Transmission Scheduling Approach for Cloud Network Collaboration Environment

In traditional cloud computing research, it is often considered that the network resources between edge devices and cloud platform are sufficient, and the symmetry between the upward link from edge devices to the cloud platform and the downward link from cloud platform to edge devices is definite. However, in many application scenarios, the network resources between edge devices and cloud platform might be limited, and the link symmetry may not be guaranteed. To solve this problem, network relay nodes are introduced to realize the data transmission between edge devices and the cloud platform. The environment in which network relay nodes that can cooperate with the cloud platform is called cloud network collaborative environment (CNCE). In CNCE, how to optimize data transmission from edge devices to cloud platform through relay nodes has become one of the most important research topics. In this paper, we focus on the following two influencing factors that previous studies ignored: (1) the multi-link and multi-constraint transmission process; and (2) the timely resource state of the relay node. Taking these factors into consideration, we design a novel data transmission scheduling algorithm, called ant colony based transmission scheduling approach (ACTS). First, we propose a multi-link optimization mechanism to optimize the constraint limits. This mechanism divides the transmission into two links called the downlink relay link and uplink relay link. For the downlink relay link, we use the store-and-forward method for the optimization. For the uplink relay link, we use the min–min method for the optimization. We use the ant colony algorithm for the overall optimization of the two links. Finally, we improve the pheromone update rule of the ant colony algorithm to avoid the algorithm from falling into a local optimum. Extensive experiments demonstrate that our proposed approach has better results in transmission efficiency than other advanced algorithms.

mmWave massive analog relay MIMO

Millimeter-Wave (mmWave) communications are a key technology to realize ultra-high data rate and ultra-low latency wireless communications. Compared with conventional communication systems in the microwave band such as 4G/LTE, mmWave communications employ a higher frequency band which allows a wider bandwidth and is suitable for large capacity communications. It is expected to be applied to various use cases such as mmWave cellular networks and vehicular networks. However, due to the strong diffraction loss and the path loss in the mmWave band, it is difficult or even impossible to achieve high channel capacity for User Equipment (UE) located in Non-Line-Of-Sight (NLOS) environments. To solve the problem, the deployment of relay nodes has been considered. In this paper, we consider the use of massive analog Relay Stations (RSs) to relay the transmission signals. By relaying the signals by a large number of RSs, an artificial Multiple-Input Multiple-Output (MIMO) propagation environment can be formed, which enables mmWave MIMO communications to the NLOS environment. We describe a theoretical study of a massive relay MIMO system and extend it to include multi-hop relays. Simulations are conducted, and the numerical results show that the proposed system achieves high data rates even in a grid-like urban environment.