Beongku An

A mobility-based clustering approach to support mobility management and multicast routing in mobile ad-hoc wireless networks

In our proposed structure, mobile nodes are organized into nonoverlapping clusters which have adaptive variable-sizes according to their respective mobility. The mobility-based clustering (MBC) approach we are proposing uses a combination of both physical and logical partitions of the network (i.e. geographic proximity and functional relation between nodes, such as mobility pattern etc.)

An entropy-based model for supporting and evaluating route stability in mobile ad hoc wireless networks

We propose an entropy-based modeling framework for supporting route stability in mobile ad hoc wireless networks. The basic motivations of the proposed modeling approach stem from the commonality observed in the location uncertainty in mobile ad hoc wireless networks and the concept of entropy. The corresponding results demonstrate that the proposed approach and parameters provide an accurate and efficient method of estimating and evaluating the route stability in dynamic mobile networks.

Geomulticast: architectures and protocols for mobile ad hoc wireless networks

Geomulticast is a specialized location-dependent multicasting technique, where messages are multicast to some specific user groups within a specific zone. In this paper, we propose architectures and protocols for supporting geomulticast services in a cost effective way and with high message delivery accuracy in the challenging environment of mobile ad hoc wireless networks. Since in mobile ad hoc networks there is no fixed infrastructure as in cellular networks we use mobility-based clustering to cluster the various mobile nodes. Using this clustering approach as the basis, we describe several geomulticast zone formulation and representation methods that present trade offs between accuracy, simplicity and cost effectiveness. Moreover, we propose a direction guided routing (DGR) protocol which creates cluster-head based limited mesh structure within a guided region, in order to deliver packets with reliability and reduced overhead to the final destinations. Two geomulticast membership management strategies which depend on geolocation storage position are also presented and investigated. Finally, we define and formulate a framework in order to evaluate the performance of the design alternatives used for the support of geomulticast services in mobile ad hoc networks. Based on this framework we evaluate the performance of the proposed architectures and protocols, and we, obtain some insight about the impact of the various design and operational parameters on the overall system performance.

On the performance of outage probability in underlay cognitive radio with imperfect CSI

In cognitive spectrum sharing systems, interference probability (IP) is one of the most important performance metrics illustrating the interference level at the primary network. In this paper, the interference probability of the primary network due to secondary underlay partial relay selection networks is investigated under the assumption of imperfect channel state information (CSI) of interference links. Numerical results show that it depends not only on the correlation efficient of interference links but also on the transmit power of secondary transmitters. It is also shown that the back-off technique is an efficient approach to guarantee the given quality of service (QoS) of the primary network. For secondary networks, we derive the outage probability over Rayleigh fading channels. Monte-Carlo simulations are performed to verify the correctness of the analysis.

Supporting multicasting in mobile ad‐hoc wireless networks: issues, challenges, and current protocols

The basic philosophy of personal communication services is to provide user-to-user, location independent communication services. The emerging group communication wireless applications, such as multipoint data dissemination and multiparty conferencing tools have made the design and development of efficient multicast techniques in mobile ad-hoc networking environments a necessity and not just a desire. Multicast protocols in mobile ad-hoc networks have been an area of active research for the past couple of years. This paper summarizes the activities and recent advances in this work-in-progress area by identifying the main issues and challenges that multicast protocols are facing in mobile ad-hoc networking environments, and by surveying several existing multicasting protocols. This article presents a classification of the current multicast protocols, discusses the functionality of the individual existing protocols, and provides a qualitative comparison of their characteristics according to several distinct features and performance parameters. Furthermore, since many of the additional issues and constraints associated with the mobile ad-hoc networks are due, to a large extent, to the attribute of user mobility, we also present an overview of research and development efforts in the area of group mobility modeling in mobile ad-hoc networks. Copyright

MHMR: mobility-based hybrid multicast routing protocol in mobile ad hoc wireless networks

The field of mobile ad hoc networking has enjoyed dramatic increase in popularity over the last few years. However, owing to the fact that such networks have dynamic, sometimes rapidly changing, random, multihop topologies, the development of efficient and applicable multicast routing protocols presents many issues and challenges. In this paper we propose a Mobility-based Hybrid Multicast Routing (MHMR) protocol suitable for mobile ad hoc networks. The main features that our proposed protocol introduces are the following: (i) mobility-based clustering and group-based hierarchical structure, in order to effectively support stability and scalability; (ii) group-based (limited) mesh structure and forwarding tree concepts, in order to support the robustness of the mesh topologies, which provides ‘limited’ redundancy and the efficiency of tree forwarding simultaneously; and (iii) combination of proactive and reactive concepts that provide low route acquisition delay and low overhead. The use of dynamic mobility-based clustering as the underlying structure is motivated by the observation that in mobile ad hoc networks communications are often among teams that tend to coordinate their movements, and as a result we can dynamically and adaptively partition the network into several groups, each with its own mobility characteristics and behaviors. In our protocol we support the creation of a limited mesh structure based on the clusterheads of the various created clusters, and not among all the members that participate in the multicast session and route, thereby reducing significantly the complexity of the created mesh topology. The performance evaluation of the proposed protocol is achieved via modeling and simulation. The corresponding results demonstrate the proposed multicast protocols efficiency in terms of packet delivery ratio, scalability, control overhead, end-to-end delay as a function of mobility, packet transmission rate, and multicast group size. Copyright

A modeling framework for supporting and evaluating performance of multi-hop paths in mobile ad-hoc wireless networks

Performance evaluation is a crucially important part of designing any mobile ad-hoc wireless networks. For a more comprehensive evaluation, mathematical analysis is essential, along with simulation. In this paper, we present a detailed analytical model for supporting and evaluating the performance of multi-hop paths in mobile ad-hoc wireless networks. More specifically, we show that the performance of multi-hop paths is affected by the stability of individual link and the distribution of hop count of multi-hop paths, and present a closed-form model for packet delivery ratio of multi-hop paths. The analytical model is validated through simulations using various settings of node mobility and network size.

Outage Performance Analysis of Relay Selection Schemes in Wireless Energy Harvesting Cooperative Networks over Non-Identical Rayleigh Fading Channels

In this paper, we study relay selection in decode-and-forward wireless energy harvesting cooperative networks. In contrast to conventional cooperative networks, the relays harvest energy from the source’s radio-frequency radiation and then use that energy to forward the source information. Considering power splitting receiver architecture used at relays to harvest energy, we are concerned with the performance of two popular relay selection schemes, namely, partial relay selection (PRS) scheme and optimal relay selection (ORS) scheme. In particular, we analyze the system performance in terms of outage probability (OP) over independent and non-identical (i.n.i.d.) Rayleigh fading channels. We derive the closed-form approximations for the system outage probabilities of both schemes and validate the analysis by the Monte-Carlo simulation. The numerical results provide comprehensive performance comparison between the PRS and ORS schemes and reveal the effect of wireless energy harvesting on the outage performances of both schemes. Additionally, we also show the advantages and drawbacks of the wireless energy harvesting cooperative networks and compare to the conventional cooperative networks.

A Cooperative Transmission Strategy using Entropy-based Relay Selection in Mobile Ad-hoc Wireless Sensor Networks with Rayleigh Fading Environments

In this paper, we propose a Cooperative Transmission Strategy using Entropy-based Relay Selection in Mobile Ad-hoc Wireless Sensor Networks (MAWSN) with Rayleigh Fading Environments. The main features and contributions of the proposed cooperative transmission strategy are as follows. First, entropy-based relay selection is used to improve data transmission reliability from a source node to a destination node. Second, we present a theoretical analysis model for the proposed cooperative transmission strategy with the outage probability of the end-to-end performance. The performance of our protocol is evaluated using analysis and simulation.

A Soft-Hard Combination-Based Cooperative Spectrum Sensing Scheme for Cognitive Radio Networks

In this paper we propose a soft-hard combination scheme, called SHC scheme, for cooperative spectrum sensing in cognitive radio networks. The SHC scheme deploys a cluster based network in which Likelihood Ratio Test (LRT)-based soft combination is applied at each cluster, and weighted decision fusion rule-based hard combination is utilized at the fusion center. The novelties of the SHC scheme are as follows: the structure of the SHC scheme reduces the complexity of cooperative detection which is an inherent limitation of soft combination schemes. By using the LRT, we can detect primary signals in a low signal-to-noise ratio regime (around an average of −15 dB). In addition, the computational complexity of the LRT is reduced since we derive the closed-form expression of the probability density function of LRT value. The SHC scheme also takes into account the different effects of large scale fading on different users in the wide area network. The simulation results show that the SHC scheme not only provides the better sensing performance compared to the conventional hard combination schemes, but also reduces sensing overhead in terms of reporting time compared to the conventional soft combination scheme using the LRT.