Firooz B. Saghezchi

A Novel Relay Selection Game in Cooperative Wireless Networks Based on Combinatorial Optimization

Multi-standard mobile devices are allowing users to experience higher data rates and ubiquitous connectivity. These advances are achieved on the expense of higher energy consumption due to the multiple active wireless interfaces. In this paper, we use one advantage of the multiple interfaces, namely short range communications. Mobile terminals (MTs) form short range cooperative network to take advantage of the good channel quality of short range links to save energy of MTs. In this cooperative network, the energy of all MTs is treated as a pool of resources, which is available for all MTs in the network. Toward this end, we propose a combinatorial optimization game to identify the problem. We derive the core solution for the relay selection game in cooperative networks. A mathematical framework to compute the achieved energy saving is derived. Simulation results using the solution of the game show that energy saving can be achieved using short range cooperation in wireless networks. The results also show the effectiveness of the proposed node selection game.

Energy efficiency of downlink packet scheduling in CoMP

The foreseen increase in the volume of mobile traffic and the correspondent increase in greenhouse gas emissions is now placing energy efficiency EE at the forefront of mobile network design. As a step towards incorporating more energy friendly mobile platforms in future networks, Third Generation Partnership Project Long-Term Evolution LTE-Advanced has adopted Coordinated Multi-Point CoMP transmission/reception because of its ability to mitigate and/or coordinate inter-cell interference. However, there is room for reducing energy consumption further by exploiting the inherent flexibility of dynamic resource allocation protocols. To this end packet scheduling schemes play a fundamental role in multi-user scenarios and provide a potential research playground for optimising energy consumption in future networks. However, there is no effective benchmark in place for experimenting new design approaches. This paper provides a first attempt to analyse the Energy Efficiency of different downlink packet scheduling in CoMP for LTE networks using classical packet scheduling algorithm approaches such as Maximum Carrier to Interference ratio MCI, Proportional Fairness PF and the Round Robin scheduling RR, and provides some input to future comparison considerations. Copyright

Coalition formation game toward green mobile terminals in heterogeneous wireless networks

Multi-standard mobile terminals (MTs) are the trend of current and future mobile devices for taking advantage of heterogeneous integration of wireless access networks and providing ubiquitous connectivity and better quality of service. Holding multiple active interfaces, however, incurs significant power consumption burdens to MTs. This not only increases the carbon footprint of MTs but also makes the batteries of MTs deplete rapidly. Consequently, mobile users may have to relentlessly look for power outlets to charge their devices, which may threaten their true mobility freedom. To this end, in this article, we propose a promising approach based on coalition formation game and inter-terminal cooperation. Our innovative approach motivates MTs to cooperate, while addressing the issue of isolating selfish players. MTs assess radio channels and disseminate the acquired information as well as their available resources to sketch a global view of the radio environment. Based on this view, coalitions are formed whenever energy saving is foreseeable. Within a coalition, MTs pool their resources and perform their tasks cooperatively to maximize their energy efficiency. Simulation results validate that the proposed approach can effectively double the battery lifetimes of MTs, while successfully eliminating selfish players from cooperative groups.

Energy-aware relay selection in cooperative wireless networks: An assignment game approach

In the future connected societies, everyone and everything will be inter-connected, under the umbrella of the Internet of Things, where tens to hundreds of devices will be serving every single citizen. However, connecting this massive number of energy-constrained devices pose a serious challenge on the wireless networking paradigm; energy efficiency still represents a major challenge within the design of the future generation of wireless networking (5G). In this paper, we address reducing energy consumption of energy-constrained wireless devices, through energy-aware cooperative relaying in future heterogeneous networks (HetNets). Using game theory concepts, we formulate the problem as an assignment game. In the first stage of the game, the optimal relay selection is formulated as a linear programming problem, whose solution assigns suitable relays to their perspective sources. In the final stage, the core solution is derived, which guarantees fair distribution of the payoff among players, to keep them satisfied and discourage them from quitting the coalition. Our solution also proposes a credit based system to reward cooperative players; hence possibly excluding selfish users from cooperative coalitions. The proposed relay selection algorithm is evaluated using extensive NS2 simulations. The simulation results show significant energy savings using cooperative relaying, reaching up to 22%, with extensive increase in battery lifetime.

Game theory and pricing strategies for demand-side management in the smart grid

Demand-side management is an effective means to optimize resource utilization in the electricity grid. The smart grid can enable the utility company to shape the users consumption by adopting appropriate pricing strategies. Having received the price information, each user may independently schedule its appliances to minimize its electricity payment. In this paper, we consider a smart grid scenario with a single utility company and multiple users where the utility company adopts day-ahead pricing strategy. We formulate the problem as a binary linear programming problem. The simulation results show that users can reduce their bills by 25% using the proposed technique.

Towards 5G: Context Aware Resource Allocation for Energy Saving

With the objective of providing high quality of service (QoS), 5G system will need to be context-aware that uses context information in a real-time mode depends on network, devices, applications, and the environment of users’. In order to continue enjoying the benefits provided by future technologies such as 5G, we need to find solutions for reducing energy consumption. One promising solution is taking advantage of the context information available in today’s networks. In this paper, we take a step towards 5G by utilizing context information in the scheduling process as conventional packet scheduling algorithms are mainly designed for increasing throughput but not for the energy saving. We investigate a Context Aware Scheduling (CAS) algorithm which considers the context information of users along with conventional metrics for scheduling. An information model of context awareness along with a context aware framework for resource management is also presented in this paper. CAS is simulated applying a system level simulator and the results obtained show that considerable amount of energy is saved by utilizing the context information compare to conventional scheduling algorithms.

Coalitional relay selection game to extend battery lifetime of multi-standard mobile terminals

Multi-standard mobile terminals (MTs) allow mobile users to experience ubiquitous connectivity and better quality of service. However, these advances come at a price of higher power consumption for MTs due to holding multiple active interfaces. In this paper, we apply multihop relaying through pervasive short range interfaces (e.g., Bluetooth, WiMedia. etc.) in the presence of an infrastructure network (e.g., LTE, WiFi, etc.) to extend the battery lifetime of multi-standard MTs. To this end, MTs exchange context information (conveying channel state information, battery level, etc.) and, whenever beneficial, form a coalition, pool their resources, and perform their tasks cooperatively to enhance their efficiency. We introduce a novel utility function to assess the profitability of cooperation. To incentivize MTs to cooperate, the achieved common utility of the coalition can be distributed among the cooperative MTs by means of energy credits using a solution concept from coalitional game theory. The simulation results validate the effectiveness of the proposed approach to extend the battery lifetime of MTs to more than double.

A Lightweight Authentication Mechanism for M2M Communications in Industrial IoT Environment

In the emerging industrial Internet of Things (IIoT) era, machine-to-machine (M2M) communication technology is considered as a key underlying technology for building IIoT environments, where devices (e.g., sensors, actuators, and gateways) are enabled to exchange information with each other in an autonomous way without human intervention. However, most of the existing M2M protocols that can be also used in the IIoT domain provide security mechanisms based on asymmetric cryptography resulting in high computational cost. As a consequence, the resource-constrained IoT devices are not able to support them appropriately and thus, many security issues arise for the IIoT environment. Therefore, lightweight security mechanisms are required for M2M communications in IIoT in order to reach its full potential. As a step toward this direction, in this paper, we propose a lightweight authentication mechanism, based only on hash and XOR operations, for M2M communications in IIoT environment. The proposed mechanism is characterized by low computational cost, communication, and storage overhead, while achieving mutual authentication, session key agreement, device’s identity confidentiality, and resistance against the following attacks: replay attack, man-in-the-middle attack, impersonation attack, and modification attack.

An incentive mechanism based on coalitional game for fair cooperation of mobile users in HANETs

Hybrid ad-hoc network (HANET) is a new and promising paradigm for decreasing the energy consumption of the mobile terminals (MTs) in a cellular network. In this network, the multi-hop functionality of ad-hoc networks is employed in an infrastructure-based network to relay the packets of MTs experiencing bad channel qualities through other MTs with better channel conditions to/from the gateway. However, the proper cooperation of MTs in a HANET scenario cannot be taken for granted as they are normally controlled by selfish users who seek to maximize their own battery lifetime. In this paper, we propose an incentive mechanism based on coalitional game theory to encourage MTs to forward packets for each other by offering energy credits to the cooperative nodes by means of a virtual central bank (VCB); where the contributions of all MTs are recorded and tracked to differentiate non-cooperative nodes from cooperative ones. We also validate the effectiveness of our proposed technique through simulation results.

Cooperative Strategies for Power Saving in Multi-standard Wireless Devices

Energy is a critical resource in the design of wireless networks since wireless devices are usually powered by batteries. Without any new approaches for energy saving, 4G mobile users will relentlessly be searching for power outlets rather than network access, and becoming once again bound to a single location. To avoid the so called 4G “energy trap” and to help wireless devices become more environment friendly, there is a clear need for disruptive strategies to address all aspects of power efficiency from the user devices through to the core infrastructure of the network and how these devices and equipment interact with each other. The ICT-C2POWER project is the vehicle that will address these issues through cognitive techniques and cooperation. The C2POWER case study is to research, develop and demonstrate energy saving technologies for multi-standard wireless mobile devices, exploiting the combination of cognitive radio and cooperative strategies, while still enabling the required performance in terms of data rate and QoS to support active applications.