Heterogeneous Multi-hop Networks Research Articles

Overloaded MIMO Bi-Directional Communication with Physical Layer Network Coding in Heterogeneous Multihop Networks

Overloaded MIMO Bi-Directional Communication with Physical Layer Network Coding in Heterogeneous Multihop Networks

Hierarchical Coded Matrix Multiplication in Heterogeneous Multihop Networks

The performance of distributed computing is restricted by the slowest worker nodes, known as stragglers, in the system. Coded computation has emerged as an efficient technique to mitigate the straggler effects in distributed computing. Most existing works only considered the computation straggler for single-hop networks. However, in multi-hop networks, the straggler effects will occur not only on worker nodes but also on relay nodes. In this paper, we consider a heterogeneous multi-hop network. The nodes in the network are heterogeneous, i.e., their computation capacities and transmission capacities are different. We propose a hierarchical coding scheme for such a network. Firstly, we reorganize it into a hierarchical network containing multiple layers. Each layer in the network consists of several groups. Then, a new hierarchical coding scheme is proposed, where coding is applied to each group to mitigate the stragglers. By taking both the computation time and transmission time into consideration, the overall task completion time is derived. To improve the performance of the network, heterogeneous hierarchical coded computation (HHCC) algorithm is proposed to provide an asymptotically optimal task allocation strategy. Compared with existing uniform uncoded, load balanced uncoded, and heterogeneous coded matrix multiplication schemes, HHCC has significant improvement.

Access Frameworks and Application Scenarios for Hybrid VLC and RF Systems: State of the Art, Challenges, and Trends

The further demand for data traffic growth makes the conventional radio frequency (RF) wireless network face ever increasing challenges such as spectrum shortage and access congestion. Visible light communication (VLC) is envisioned as a promising candidate for wireless communication in the future, but it also has limitations like limited coverage and inconvenient uplinks. Naturally, it is a rational strategy to combine VLC and RF systems to form hybrid systems, which can take full advantage of high data rate in VLC and wide coverage in RF. In this article, the current research on hybrid VLC and RF systems is reviewed. First, the structures of hybrid access frameworks are introduced as complementary single-hop networks and heterogeneous multihop networks, while common frameworks in the current literature are summarized. Moreover, the technical characteristics and specific advantages of hybrid VLC and RF systems are discussed in different application scenarios for high data rate, high energy efficiency, and high reliability. Finally, the future trends of hybrid VLC and RF systems are looked forward to in some typical enabling technologies.

Survey on Reactive Medium Access Control Mechanism for Peer to Peer Heterogeneous Multi Hop Networks

Based on the functionality, wireless multi-hop network (MANETs) can be divided as mobile ad hoc networks, wireless mesh networks (WSN). WSN is similar to MANETs with the application of monitoring, and it is an extension of infrastructure based single-hop wireless network technology. However, these multi-hop technologies have its applications and limitations depending on their implementation and operation. Analysis: In this work our primary focus is to review the current work on developed reactive MAC protocol for multiple -beam smart –antennas in MANETs and WMNs and secondly focus to review the current work on developed efficient and reliable MAC methods for wireless multi-hop networks. Findings: Based on our analysis we find the method to describe the Medium Access Control Problems for Reliable Data Communication. Application: This work is used to develop reactive medium access control mechanism for peer to peer heterogeneous multi hop networks.

Cooperative Interference Mitigation for Heterogeneous Multi-Hop Wireless Networks Coexistence

This paper studies the coexistence of heterogeneous multi-hop networks, which use different physical-layer technologies. We propose a new paradigm, called cooperative interference mitigation (CIM), which exploits recent advancement in interference cancellation (IC), such as technology-independent multiple output. CIM makes it possible for disparate networks to cooperatively mitigate the interference to/from each other to enhance everyone’s performance. We first show the feasibility of CIM among heterogeneous multi-hop networks by exploiting only channel-ratio information. Then, we establish two tractable models to characterize the CIM behaviors of both networks by using full IC and receiver-side IC only. We propose two bi-criteria optimization problems aiming at maximizing both networks’ throughput, while cooperatively canceling the interference between them based on our two models. Several simulations are carried out to compare the Pareto-optimal throughput curves by using our CIM paradigms and traditional interference-avoidance (IAV) paradigm. By comparing the results from CIM and IAV, we show that CIM could remarkably improve the coexisting networks’ throughput in different network settings.

Modeling Latency and Reliability of Hybrid Technology Networking

Operational safety and security are the key concerns of the North American railroad industry. Of growing importance is the ability for real-time identification, monitoring, and fault alerting of freight railcars and their myriad components. This vision of an Internet of Things applied to the transportation industry has widespread benefits and applications. Wireless sensor networks (WSNs) have been extensively used for addressing such challenges. However, the nature of a train's arrangement requires the sensors to be placed in a long linear network topology. Given the limitations in radio transmission range and network depth of common WSN solutions like ZigBee, it is infeasible to use them for such applications. Furthermore, due to its low throughput, severe packet loss and high latency may occur, which is unacceptable, especially for failure alert messages. Therefore, we have proposed a heterogeneous multihop network approach called hybrid technology networking (HTN) that employs WiFi together with ZigBee. In this paper, we derive a mathematical model to illustrate HTNs superior performance compared with conventional ZigBee-based WSNs. Specifically, we analyze the delay and reliability of HTN and ZigBee and verify the analytical results against our simulations.

Issues in integrating cellular networks, wlans, and manets: a futuristic heterogeneous wireless network

The popularity of wireless communication systems can be seen almost everywhere in the form of cellular networks, WLANs, and WPANs. In addition, small portable devices have been increasingly equipped with multiple communication interfaces building a heterogeneous environment in terms of access technologies. The desired ubiquitous computing environment of the future has to exploit this multitude of connectivity alternatives resulting from diverse wireless communication systems and different access technologies to provide useful services with guaranteed quality to users. Many new applications require a ubiquitous computing environment capable of accessing information from different portable devices at any time and everywhere. This has motivated researchers to integrate various wireless platforms such as cellular networks, WLANs, and MANETs. Integration of different technologies with different capabilities and functionalities is an extremely complex task and involves issues at all layers of the protocol stack. This article envisions an architecture for state-of-the-art heterogeneous multihop networks, and identifies research issues that need to be addressed for successful integration of heterogeneous technologies for the next generation of wireless and mobile networks.