Applying MIMO Techniques to Minimize Energy Consumption for Long Distances Communications in Wireless Sensor Networks

Abstract

This paper explores the usage of cooperative multiple input multiple output (MIMO) technique to minimize energy consumption used to establish communications among distant nodes in a wireless sensor network (WSN). As energy depletion is an outstanding problem in WSN research field, a number of techniques aim to preserve such resource, especially by means of savings during communication among sensor nodes. One such wide used technique is multi-hop communication to diminish the energy required by a single node to transmit a given message, providing a homogeneous consumption of the energy resources among the nodes in the network. However, it is not the case that multi-hop is always more efficient than single-hop, even that it may represent a great depletion of a single node's energy. In this paper a cooperative MIMO transmission technique for WSN is presented, which is compared to single-hop and multi-hop transmission ones, highlighting its advantages in relation to both. Simulation results support the statement about the utility in applying the proposed technique for energy saving purposes. 2Motivation and Background WSN CommunicationsEnergy consumption is the paramount problem that still hinders a larger usage of WSN nowadays [2]. Due to the constrained energy budget that the sensor nodes count with, a careful usage of this resource in each individual node has to be taken into account in order to enlarge the lifespan of the entire network. As all distributed systems, WSNs have their basic functionalities highly dependent on the communication among their nodes. However, as wireless communications are very costly in terms of energy consumption, it leads to an impasse about the usage of the communications. The solution of this impasse has to consider an efficient usage of the communication in order to minimize the waste of energy. Wireless sensor networks usually present a planar or a hierarchical architecture [5]. In the first one, sink nodes disseminate information in the network, which are transmitted from node to node according to the type of the information being disseminated, such as queries to specific locations for instance, and receive the replies by similar multi-hop communications from the nodes that provide the required information. Hierarchical-based WSNs restrict the more expensive communications to special nodes that exchange messages among them and are responsible for a number of other nodes, as representatives. Examples of such WSNs are clustered-based WSNs, in which those special sensor nodes are called cluster-heads, and they can be

Applying Cooperative MIMO Technique in an Adaptive Routing Mechanism for Wireless Sensor Networks

“…Even for fully connected networks (no node failures) cooperative MIMO enabled networks are evidently more efficient than standard networks, this is due to the fact that packets that need to be forwarded across long distances employ a large number of hops in standard networks. In this cases multi-hop is less efficient than a single long haul cooperative MIMO transmission across the same distance as shown in [9].…”

“…On [9] it was demonstrated that due to the number of transmissions necessary to synchronized and spread data between the members of the cooperative MIMO clusters this communication scheme is only efficient when employed over large distances. A method for choosing between the available transmission methods must be implemented for the cooperative MIMO to be efficiently employed in WSNs.…”

“…In [8] cooperative MIMO transmissions are studied, and SIMO and MISO cases are taken into account, however, only Alamouti coding is considered and it is assumed that intermediary hops are error free. In [9] a energy analysis considering single-hop, multihop and cooperative MIMO is presented. Results obtained in this work showed that cooperative MIMO is only advantageous when long distances are involved.…”

Cooperative beamforming in ad-hoc networks with sublinear transmission power

“…The algorithms of this work are based on the following model for signal transmission over a communication channel 1 . For analyzing sender beamforming, a channel includes m transmitters which simultaneously emit a signal, i.e.…”

“…De Freitas et al [1] use MIMO techniques in wireless sensor networks to reduce the energy consumption. They differentiate between energy consumption for sending and receiving in a transmission and state in which cases multi-hop routing outperforms single-hop direct communication.…”