Alberto Nascimento

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.

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.

Jointly Cross-Layer Scheduling and Dynamic Resource Allocation for RT and NRT Traffic Types for IEEE802.16e

Mobile communications has witnessed an exponential increase in the amount of users, services and applications. New high bandwidth consuming applications are targeted for B3G networks raising more stringent requirements for Dynamic Resource Allocation (DRA) architectures and packet schedulers that must be spectrum efficient and deliver QoS for heterogeneous applications and services. In this paper we propose a new cross layer-based architecture framework embedded in a newly designed DRA architecture for the Mobile WiMAX standard. System level simulation results show that the proposed architecture can be considered a viable candidate solution for supporting mixed services in a cost-effective manner in contrast to existing approaches.

Dual-Homomorphic message authentication code scheme for network coding-enabled wireless sensor networks

Network coding has shown a considerable improvement in terms of capacity and robustness compared to traditional store-and-forward transmission paradigm. However, since the intermediate nodes in network coding-enabled networks have the ability to change the packets en route, network coding-enabled networks are vulnerable to pollution attacks where a small number of polluted messages can corrupt bunches of legitimate messages. Recently, research effort has been put on schemes for protecting the transmitted messages against data pollution attacks. However, most of them cannot resist tag pollution attacks. This paper presents a new homomorphic MAC-based scheme, called Dual-Homomorphic MAC (Dual-HMAC), for network coding-enabled wireless sensor networks. The proposed scheme makes use of two types of tags (i.e., MACs and D-MACs) to provide resistance against data pollution attacks and partially tag pollution attacks. Furthermore, our proposed scheme presents low communication overhead and low computational complexity compared to other existing schemes.

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.

Quadratic Programming for Demand-Side Management in the Smart Grid

Demand-Side Management (DSM) is an effective means to optimize resource utilization in the electricity grid. It makes the electricity consumption pattern of users more even, reducing the Peak-to-Average demand Ratio (PAR) in the power system. The utility company can monitor and shape the hourly electricity consumption of the users by adopting an appropriate pricing strategy and advertising it online exploiting the underlying Smart Grid infrastructure. On the other hand, the users can monitor the hourly price of electricity in the market and based on the price variation, they can schedule their appliances to minimize their electricity payment, without compromising their daily need. In this paper, we consider a DSM problem where the company adopts a quadratic pricing strategy to encourage the users to have a flat consumption pattern. We formulate the problem incorporating Quadratic Programming (QP). The simulation results show that the QP approach reduces the PAR drastically.

Cluster cooperation for energy saving in wireless personal networks

Recent years have witnessed an explosive growth of wireless technologies and applications. Without disruptive new approaches for energy saving, 4G mobile users will relentlessly be searching for power outlets rather than network access, and become once again bound to a single location. In this paper, we explore the cooperation among nodes in a cluster for the main goal of saving the battery power of mobile terminals. This paper studies the possibility of decreasing energy consumption through relaying data from all nodes in a cluster through the cluster head. Simulation results are presented from a scenario composed of nodes supporting both UWB (among them) and WiFi communications to an AP. Results demonstrate the gains in energy saving and the benefits incurred to QoS requirements, namely throughput and packet delay. The work also guarantees that the required QoS is always maintained.

A null space-based MAC scheme against pollution attacks to Random linear Network Coding

Network Coding has significantly shown the achievable throughput and robustness in wireless Networks. However, network coding-enabled networks are susceptible to pollution attacks where a small number of polluted messages will propagate due to recoding and corrupt bunches of legitimate messages. Several lightweight Homomorphic Message Authentication Code (HMAC) schemes have been proposed for protecting the transmitted data against pollution attacks; however, most of them are not appropriate for wireless networks or cannot resist tag pollution attacks. In this paper, we present a computationally efficient null space-based homomorphic MAC scheme, for network coding-enabled wireless networks. The proposed scheme makes use of two types of tags (i.e., MACs and D-MACs) to provide resistance against data pollution and tag pollution attacks. Furthermore, we demonstrate that due to its lightweight nature, our proposed scheme incurs a minimal complexity compared to other related schemes.

An efficient MAC-signature scheme for authentication in XOR network coding

An inherent weakness of network coding is that it is vulnerable to pollute attacks from adversaries, which may jeopardize its advantages such as throughput enhancement. Message Authentication Code (MAC) is commonly used scheme to provide integrity against data pollution by appending data and shared-key dependent tags. However, this scheme results in a new type of pollution called tag pollution, where a packet with polluted tags may traffic multiple hops before detection and result in network bandwidth waste. We propose a hybrid technical scheme, called MSXOR, which can detect tag pollution with low communication and computation overhead. We address the pollution attacks by designing an efficient MAC scheme suitable for multicast XOR network coding, and tag pollution attacks by appending a signature of all the MACs. Our experimental results show that it slightly increases the computation complexity, for the sake of resisting to tag pollution.

An improved homomorphic message authentication code scheme for RLNC-enabled wireless networks

Network Coding has significantly improved the achievable throughput and robustness compared to traditional store-and-forward transmission paradigm. However, network coding-enabled networks are susceptible to pollution attack where a small number of polluted messages will propagate in recoding and corrupt bunches of legitimate messages. Recently, several light weight Homomorphic Message Authentication Code (HMAC) schemes were proposed for protecting the transmitted data against pollution attacks; however, most of them cannot resist tag pollution attacks. This paper presents an improved scheme, called Dual-HMAC, for Random Linear Network Coding (RLNC)-enabled wireless networks. The proposed scheme makes use of two types of tags (i.e., HMACs) to provide resistance against data pollution attacks and partially tag pollution attacks.