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The realization of mobile edge computing (MEC) over emerging fifth (5G) generation of wireless systems arises as a driving-force in the future of cloud computing. In order to cope with the volume, variety, and velocity of the IoT traffic while making optimal use of the network infrastructure, a synergistic exploitation of MEC and 5G should be put forward to support advanced resource management applications. In this paper, we propose the use of joint parallelism between wireless and cloud domains to efficiently respond to mobile data deluge. We review the literature, discuss the enabling network architecture, potentials, challenges, and open issues related to the realization of such level of parallelism. We present and evaluate two design examples — parallel computation offload method (PCOM) and parallel transmission and storage method (PTSM)—which outline the benefits of parallelism for computation-hungry and storage-hungry applications, respectively. Results of our optimization formulation show that PCOM and PTSM are able to make an efficient use of the network resources and support a heavy instantaneous workload by means of the parallelism.

Cognitive Wireless Sensor Networks (CWSN) are known to be energy constrained because they are required to perform cognitive functions in addition to sensing, which reduces the lifetime of CWSN. RF Wireless Energy Harvesting (RFWEH) is known to improve network lifetime by compensating energy losses through harvesting gain without any additional hardware. However, the allocation of time slots for energy harvesting results in degradation of network parameters such as latency and throughput. In this paper, we propose an energy harvesting MAC protocol (R-MAC) for CWSN that balances network energy losses with harvested energy gains, thereby resulting in a self sustainable CWSN. This is done such that both latency and throughput remain close to predefined target values. R-MAC employs TDMA and relies on clustering for creation and dissemination of the schedule. We also propose an algorithm to add harvesting slots based on a recursive regression technique to achieve the energy balance. Using simulation we compared its performance with the well known cognitive KoNMAC protocol, after incorporating energy harvesting in it. The simulation results show that the proposed protocol increases the lifetime of the CWSN nodes substantially, resulting in an energy self sufficient network while maintaining throughput and latency within acceptable limits.

To cope with the pressing need of running content-rich multimedia applications and real-time services, Quality of Service (QoS) support has become a vital component in today’s wireless networks. Using beamforming antennas in multi-hop wireless networks can potentially spare more network resources which can be utilized to provide additional QoS guarantees. However, these opportunities are still under-explored. In this chapter, we develop a framework to analyze conflicts between wireless links in the presence of contention-based directional MAC protocols. Based on a novel taxonomy, we classify the link conflicts and propose a novel colored conflict graph abstraction to model the interdependencies between wireless links. Our analytical framework can be utilized as a basis to design several interference-aware and QoS-aware schemes for contention-based multi-hop wireless networks with beamforming antennas. Based on our analysis, we formulate the bandwidth-guaranteed routing problem as an optimization problem. Since the problem is NP-hard, we present a heuristic algorithm for joint routing and admission control to find single-path bandwidth-guaranteed routes. Using extensive simulations, we demonstrate the accuracy of our conflict analysis and the ability of the proposed algorithm to provide QoS guarantees along with efficient channel utilization.

Directional antenna can boost the performance of wireless networks in terms of coverage, connectivity, spatial reuse and capacity compare to the omni-direction antenna. To meet the ever- increasing demands for high data rate; industry, academia and research groups are investigating several areas of wireless technology to improve the capacity of the system. Directional beamforming antennas, directional multi-hop routing, quality of service aware support and the use of millimeter wave spectrum are some of the key areas received considerable attention in the research community. Although all of the above-mentioned technologies provide potential improvement, they also have technical challenges to address for further improvement. In this chapter we present some open issues and research directions for future generation WLAN systems.

Automation of modern industrial plants require real-time tracking of object locations and sensing of local and ambient parameters for variety of applications such as counting and tracking of objects in assembly line, detection and positioning of failures of machines etc. Mostly, discrete Real Time Location System (RTLS) performs object tracking in existing industrial automation without its integration with the sensing and control network, which constrains application's responsiveness. In this paper, we propose an integrated solution of Wireless Positioning Sensor Network (WPSN) that is designed for accuracy, reliability, scalability and optimal network operation. The proposed WPSN is applicable for harsh indoor industrial environments for not only monitoring and control of plant operations but also for identification, localization and tracking of assets and inventory in industrial warehouses. The indoor industrial environment poses challenging conditions for radio signal propagation that adversely affects reliability of communication of sensing and location data. We approach reliability by incorporating redundancy and making our network reconfigurable through adaptive intelligent learning process. We employ adaptive clustering technique to address the need of scalable deployment for varied industrial scenarios. We include hybrid localization scheme to provide high precision positioning but with fallback reduced precision operation to deal with long-term channel impairment. The WPSN is connected with backend cloud infrastructure for low cost monitoring and control.

In this paper, we propose an optimal power allocation scheme that minimizes the energy per bit of worst user (i.e., the user with highest energy per bit) in a multiuser wireless communication network. The problem of determining energy efficient power allocation to improve the worst user is a constrained non-convex nonlinear fractional programming problem. We propose an iterative energy efficient power allocation algorithm that guarantees optimal solution. We use parametric equivalent formulation to get the optimal solution. Numerical solutions obtained using simulations are presented and compared with equal power allocation scheme.

Cooperative diversity techniques have received a lot of attention recently due to their ability to provide spatial diversity in fading wireless environment without the requirement of implementing multiple antenna on the same device. It increases link reliability, provides higher capacity, reduces transmit power, and extends transmission range for the same level of performance and modulation rate. In this paper, we study the achievable gain of cooperative communications from a wireless cross-layer point of view in multi hop networks. We propose two routing algorithms applicable for wireless ad hoc networks. First, we propose an edge node based on a greedy cooperative routing (ENBGCR) algorithm, where we modify the geographic routing algorithm to incorporate the cooperative transmission and extend the coverage range of the nodes. The main objective of ENBGCR algorithm is to minimize the number of hops that messages transverse to reach their destination. Then the energy-efficient cooperative routing algorithm is proposed to minimize the end-to-end total transmission power subject to end-to-end target data rate. Simulation results for both algorithms show that the proposed strategies have great improvement in terms of delay and power saving respectively for the same quality of service requirement as compared to traditional algorithms.

The beamforming antenna technology is a promising solution to many challenges facing wireless ad hoc networks. Beamforming antennas have the ability to increase the spatial reuse, improve the transmission reliability, extend the transmission range and/or save the power consumption. If they are effectively used, they can significantly improve the network capacity, lifetime, connectivity and security. However, traditional Medium Access Control (MAC) protocols fail to exploit the potential benefits due to the unique characteristics of wireless ad hoc networks with beamforming antennas. To that end, numerous MAC protocols have been designed over the years to harness the offered potential. In this paper, we survey the literature on MAC protocols proposed for wireless ad hoc networks with beamforming antennas during the last decade. We discuss the main beamforming-related challenges facing the medium access control in ad hoc networks. We present taxonomy of the MAC protocols proposed in the literature based on their mode of operation and the mechanisms used to address the challenges. In addition, we provide a qualitative comparison of the protocols highlighting their features, benefits and requirements. Finally, we provide directions for possible future work.

Utilizing smart beamforming antennas in contention-based wireless mesh networks has proven to provide a significant increase in the network capacity. Nevertheless, their effectiveness in providing additional QoS guarantees is still under-explored. In this paper, we develop a framework for analyzing conflicts on wireless links considering both the physical interference and the operation of the underlying directional MAC protocol. Based on a novel taxonomy, we classify the link conflicts into several categories and propose a novel colored conflict graph abstraction to model the network interference pattern in the presence of contention-based directional MAC protocols. Using the proposed colored conflict graph, we derive a closed form expression for the probability of successful transmission over a wireless link given that all the bandwidth requirements are satisfied. Based on our analysis, we formulate the bandwidth-guaranteed routing problem as an optimization problem. Since the problem is NP-hard, we present a heuristic algorithm for joint routing and admission control to find single-path bandwidth-guaranteed routes. Using extensive simulations, we demonstrate the accuracy of our conflict analysis and the ability of the proposed algorithm to provide QoS guarantees along with efficient channel utilization.

Beamforming antennas promise a significant increase in the spatial reuse of the wireless medium when deployed in multihop wireless networks. However, existing directional Medium Access Control (MAC) protocols with the default binary exponential backoff mechanism are not capable of fully exploiting the offered potential. In this paper, we discuss various issues involved in the design of MAC protocols specific for beamforming antennas. Based on our discussion, we argue that the traditional binary exponential backoff mechanism limits the possible spatial reuse and aggravates some beamforming-related problems such as deafness and head-of-line blocking. To grasp the transmission opportunities offered by beamforming antennas, we design an Opportunistic Directional MAC (OPDMAC) protocol for multihop wireless networks. The OPDMAC protocol employs a novel backoff mechanism in which the node is not forced to undergo idle backoff after a transmission failure but can rather take the opportunity of transmitting other outstanding packets in other directions. This mechanism minimizes the idle waiting time and increases the channel utilization significantly and thereby enables OPDMAC to enhance the spatial reusability of the wireless medium and reduce the impact of the deafness problem without additional overhead. Through extensive simulations, we demonstrate that OPDMAC enhances the performance in terms of throughput, delay, packet delivery ratio, and fairness. To further improve its performance, we discuss and evaluate the benefits of carefully choosing some protocol parameters instead of using the default values commonly used by other directional MAC protocols.

Cooperative communication aims to achieve spatial diversity gain via the cooperation of user terminals in transmission without requiring multiple transceiver antennas on the same node. It employs one or more terminals as relays in the neighbourhood of the transmitter and the receiver, which collaborate in the transmission and serve as a virtual MIMO antenna array. Allowing cooperation in wireless communication engenders new problems related to resource allocation and relay selection. Optimal relay selection is vital for reaping the performance benefit of cooperative communication. It is a challenging task to share channel information in timely and distributed manner and at the same time make optimal selection of relay in a time varying radio environment. This paper presents a comprehensive survey of distributed relay selection schemes for cooperative communication that have been proposed in the literature. We discuss various classifications of relay selection schemes and describe their characteristics and functionality. We then present a qualitative comparison of their performance against a set of representative metrics. Finally, we discuss some of their shortcomings and suggest some research directions.

In this paper, we propose an optimal power allocation scheme that minimizes the energy per bit of worst user (i.e., the user with highest energy per bit) in a multiuser wireless communication network. The problem of determining energy efficient power allocation to improve the worst user is a constrained non-convex nonlinear fractional programming problem. We propose an iterative energy efficient power allocation algorithm that guarantees optimal solution. We use parametric equivalent formulation to get the optimal solution. Numerical solutions obtained using simulations are presented and compared with equal power allocation scheme.

Handover performance is very important when evaluating IP mobility protocols. If not performed efficiently, handover delays, jitters, and packet loss directly impact application performance. We propose a new architecture for providing efficient handover, while being able to coexist with other protocols. We propose a paradigm for multicast-based micromobility (M&M), where a visiting mobile is assigned a multicast address to use while moving within a domain. The multicast address is obtained using algorithmic mapping, and handover is achieved using multicast join/prune mechanisms. This paper outlines a framework for the design and evaluation of micromobility protocols. We define a suite of protocols (called candidate access router set) to enable multiple-access routers to receive traffic for the mobile node. By changing the number of such routers, timing, and buffering parameters, the protocol may be fine-tuned for specific technologies (e.g., 802.11) and handover scenarios. Extensive NS-2 simulations are used to compare M&M with other micromobility schemes-cellular Internet protocol (CIP) and handoff-aware wireless access Internet infrastructure (HAWAII). For proactive handover scenarios, our results show that M&M and CIP show lower handover delay and packet reordering than HAWAII. M&M, however, handles multiple border routers in a domain, where CIP fails. Also, for scenarios of reactive handover and coverage gaps M&M clearly outperforms CIP and HAWAII.

Energy consumption is a key issue in wireless ad hoc and sensor networks. Cooperative communication represents a potential candidate to improve the energy efficiency of wireless networks and this efficiency can be further improved by considering the variable packet size. In this paper, we address the question of the optimal packet size for data that improves the efficiency of energy consumption in energy constrained wireless cooperative ad hoc networks. Energy efficiency is used as an optimization metric and the problem is formulated as a nonlinear optimization problem. The accurate solution of optimal problems is crucial and existing methods proposed for such formulation can still converge to a local solution. In this paper, a novel global optimization approach based on a branch and bound (BB) framework and convexification techniques that address the solution to global optimality known as αBB is introduced. The numerical results show that, this algorithm offers mathematical guarantees for convergence to a point arbitrarily close to the global minimum in reasonable computational time.

Cooperative relaying techniques have been shown to provide spatial diversity in fading wireless environment. As a result, they increase link reliability, provide higher capacity, reduce transmit power, and extend transmission range as opposed to non-cooperative transmission (direct transmission). Although the use of cooperative relaying has been proven to achieve those gains in the absence of interference (single flow), it is not clear how much gain we can expect from using cooperative relaying in multi-flow scenario specifically the total network capacity. The network capacity in multi-hop multi-flow settings is severely affected by interference between links and, this effect increases when the cooperative relaying is imposed. In this paper, we use a clique based capacity analysis to investigate the performance gain (loss) on network capacity for wireless ad hoc networks by using cooperative relaying. It is observed that the throughput drops significantly when cooperative links are imposed in the network.

The demand for QoS has made its support an essential component in today's wireless networks. The use of directional antennas in multi-hop wireless networks is known to provide substantial increase in the utilization of the wireless medium. However its effectiveness in providing QoS assured routing is unexplored. In this paper, we study the problem of bandwidth guaranteed routing in contention-based wireless mesh networks with directional antennas. We present a detailed analysis for the interference pattern of such networks taking into account the challenges imposed by the use of directional antennas such as deafness. Based upon this analysis, we formulate the QoS routing problem as an optimization problem. We then present a routing and admission control heuristic to solve the problem. Our simulation results demonstrate the effectiveness of our routing scheme and the necessity of admission control for QoS support.

Directional antennas in multihop wireless networks offer a potential increase in the spatial reuse of the wireless channel. However, existing directional MAC protocols are not capable of fully exploiting this essential benefit. In this paper, we propose OPDMAC which is an opportunistic directional MAC protocol that is motivated by the possibility of achieving higher spatial reuse. The proposed protocol is novel in its backoff mechanism with directional antennas. If a node is forced to backoff due to a missing CTS or acknowledgement in one direction, OPDMAC explores transmission opportunity in other directions. This minimizes the idle wait time of the wireless channel and increase the channel utilization. In addition, OPDMAC is found to decrease the effect of deafness without additional control overhead. Our simulation results show that OPDMAC outperforms existing directional MAC protocols in terms of throughput, delay and fairness.

Utilizing smart antennas in multi-hop wireless networks can boost their performance. However, most of the work done in the context of wireless adhoc and sensor networking assume ideal or over-simplistic antenna patterns that overrate the performance benefits. In this paper, we compute the optimal throughput of multi-hop wireless networks with realistic smart antenna model. Our goal is to evaluate the network performance degradation using real smart antenna as compared to using the ideal model. We derive a generic interference model that can accommodate any antenna radiation pattern. We formulate the problem as a multi-commodity flow problem with novel interference constraints derived from our generic interference model. Our numerical results show that using a real-world smart antenna in a dense network results in up to 55% degradation in the throughput as compared to the case of ideal flat-topped antenna, whereas the throughput degradation is as much as 37% in a sparse network.

Recently Wireless Mesh Network (WMN) has become popular especially for its low cost deployment in the areas of poor network infrastructure and terrain of difficult deployment. Although paths in WMN backbone network are stable, the access link contention can severely constrain the end-to-end throughput. We proposed an integrated routing system for WMN that exploits both paths through the backbone network and through the ad-hoc access network of mobile nodes. The ad-hoc path is considered as an alternative path and is used only when the primary backbone path is severely constrained due to access links contention. We have shown through simulation that alternative path is effective in delivering high throughput in that situation. We also proposed a scheme for initiating the route discovery of the ad-hoc path. We investigated the use of OSPF in the backbone network and proposed solutions of dealing with multi-area OSPF configuration in the backbone and auto-configuration of OSPF wireless links.