Distributed Cooperative Routing and Hybrid ARQ in MIMOBLAST Ad Hoc Networks

Cooperation has proved to be an effective technique for improving the performance and the efficiency of wireless networks. Most of the existing work on cooperation focuses on the physical layer, with the aim of enhancing the capacity and the quality of a single link. In this paper we propose a cooperative protocol that melds physical, MAC and routing layers to increase the performance of a MIMO-BLAST ad hoc network, where nodes are allowed to transmit simultaneously. Nodes try to resolve in-range delivery of packets with an adaptive distributed Hybrid ARQ scheme to counteract interference from simultaneously active communications, while dynamic route selection is implemented for avoiding transmissions over links with harsh fading conditions. We assess the performance of our scheme through detailed simulations

Cooperation techniques for wireless systems from a networking perspective

The impact of fading and other impairments in wireless channels can be counteracted by leveraging communication diversity and introducing cooperative paradigms, where third-party nodes contribute to assist the communication. In this article we describe and evaluate two possible cooperative approaches, cooperative relaying and coded cooperation. Different from existing works where similar evaluations are mainly performed investigating a single link, we take a network-wide perspective to evaluate the effects of cooperation not only where it is performed but also on other links. We focus on a multiple-input multiple-output ad hoc scenario and show that the improvement brought by cooperative routing and coded cooperation is not always sufficient; in certain cases the former can be ineffective if no proper relay can be selected, and the latter leads to an overall increase of interference, thus worsening the quality of surrounding links. However, we suggest that these two features can be combined in an advantageous manner in order to mutually overcome their problems. Such a joint solution is shown to achieve a significant improvement over the two individual approaches. We conclude by discussing future evolutions of the cooperation paradigm, including both cooperative routing and coded cooperation, and their advanced implementation issues

A distributed solution to estimation problems in wireless sensor networks leveraging broadcast communication.

The wide variety of applications for wireless sensor networks combined with the energy constrained nature of sensor nodes has motivated research on algorithms for in-network estimation of measured physical quantities to reduce the amount of data that needs to be transmitted to the sink. The main contribution of this work is a distributed estimation solution that leverages the broadcast nature of the wireless channel in sensor networks. We present a data dissemination protocol, called Kalsip, which is designed to support the implementation of our distributed estimation algorithm based on Kalman filters. We show, through analysis and simulation, that our protocol provides accurate estimation of physical properties while minimizing the number of transmissions needed and requiring nodes to only overhear estimates broadcast by their neighbors