Cooperative Multiple-input Multiple-output Scheme Research Articles

A New Cooperative MIMO Scheme Based on SM for Energy-Efficiency Improvement in Wireless Sensor Network

Improving the energy efficiency in wireless sensor networks (WSN) has attracted considerable attention nowadays. The multiple-input multiple-output (MIMO) technique has been proved as a good candidate for improving the energy efficiency, but it may not be feasible in WSN which is due to the size limitation of the sensor node. As a solution, the cooperative multiple-input multiple-output (CMIMO) technique overcomes this constraint and shows a dramatically good performance. In this paper, a new CMIMO scheme based on the spatial modulation (SM) technique named CMIMO-SM is proposed for energy-efficiency improvement. We first establish the system model of CMIMO-SM. Based on this model, the transmission approach is introduced graphically. In order to evaluate the performance of the proposed scheme, a detailed analysis in terms of energy consumption per bit of the proposed scheme compared with the conventional CMIMO is presented. Later, under the guide of this new scheme we extend our proposed CMIMO-SM to a multihop clustered WSN for further achieving energy efficiency by finding an optimal hop-length. Equidistant hop as the traditional scheme will be compared in this paper. Results from the simulations and numerical experiments indicate that by the use of the proposed scheme, significant savings in terms of total energy consumption can be achieved. Combining the proposed scheme with monitoring sensor node will provide a good performance in arbitrary deployed WSN such as forest fire detection system.

Energy Efficient Multi-Hop Wireless Sensor Networks with Cooperative MIMO Scheme

For wireless sensor networks, energy efficiency is one of the most important subjects in recent research. In this paper, an energy-efficient multi-hop scheme based on cooperative MIMO (multiple-input multiple-output) technique is proposed for wireless sensor networks. Different from other papers, we consider a single cluster transmission scenario in which energy consumption is optimized by selecting the hop length and modulation constellation size. The optimal energy consumption formula is derived and proved mathematically. In addition, the minimum energy consumption per bit is calculated numerically.

A new distributed cooperative MIMO scheme for mobile ad hoc networks

In this paper, we introduce a new communication scheme based on cooperative multiple-input multiple-output (MIMO) communication for mobile ad hoc networks (MANETs) in which nodes are endowed with M antennas. According to our new approach, adjacent nodes no longer interfere with each other but rather cooperate attempting to communicate concurrently. In our scheme, during transmissions, the nodes send packets from only one of their antennas, while during reception, they use all of their antennas to receive and decode packets from multiple close nodes simultaneously. Therefore, each distributed MIMO system in this scheme consists of multiple transmitting nodes acting as a single-array of multiple antennas. We derive upper and lower bounds on the receiver node ergodic capacity in the network where the wireless channel is modeled with both large and small-scale fluctuations. These bounds are compared with Monte-Carlo simulation of point-to-point and cooperative MIMO communications in MANETs. We demonstrate that the capacity of MANETs with multiple antennas is improved using cooperation compared to non-cooperative schemes, i.e., point-to-point MIMO communication. In addition, under the above communication model, we demonstrate that the lower and upper bounds of the ergodic capacity grows linearly with the number of receiving antennas M.

An LDPC coded cooperative MIMO scheme over Rayleigh fading channels with unknown channel state information

This paper describes a coded cooperative multiple-input multiple-output (MIMO) scheme, where structured low-density parity-check (LDPC) codes belonging to a family of repeat-accumulate (RA) codes are employed. The outage probability of the scheme over Rayleigh fading channels is deduced. In an unknown channel state information (CSI) scenario, adaptive transversal filters based on a spatio-temporal recursive least squares (ST-RLS) algorithm are adopted in the destination to realize receive diversity gain. Also, a joint ‘Min-Sum’ iterative decoding is effectively carried out in the destination. Such a decoding algorithm agrees with the bilayer Tanner graph that can be used to fully characterize two distinct structured LDPC codes employed by the source and relay. Simulation results verify the effectiveness of the adopted filter in the coded cooperative MIMO scheme. Theoretical analysis and numerical simulations show that the LDPC coded cooperative MIMO scheme can well combine cooperation diversity, multi-receive diversity, and channel coding gains, and clearly outperforms coded noncooperation schemes under the same conditions.

Energy saving in cluster-based wireless sensor networks through cooperative MIMO with idle-node participation

In cluster-based wireless sensor networks, the energy could be saved when the nodes that have data to transmit participate in cooperative multiple-input multiple-output (MIMO). In this paper, by making the idle nodes that have no data to transmit participate in the cooperative MIMO, it is found that much more energy could be saved. The number of the idle nodes that participate in the cooperative MIMO is optimized to minimize the total energy consumption. It is also found that the optimal number of all the nodes participating in cooperative communication does not vary with the number of nodes that have data to transmit. The proposition is proved mathematically. The influence of long-haul distance and modulation constellation size on the total energy consumption is investigated. A cooperative MIMO scheme with help-node participation is proposed and the simulation results show that the proposed scheme achieves significant energy saving.

Cross-layer design of energy-constrained networks using cooperative MIMO techniques

We consider networks where energy is a limited resource so that energy consumption must be minimized while satisfying given throughput requirements. For such networks, cross-layer design coupled with node cooperation can significantly reduce both energy consumption and delay. In this paper, we propose a cooperative multiple-input multiple-output (MIMO) technique where multiple nodes within a cluster cooperate in signal transmission and/or reception. In our scheme, local information exchange within the cluster is not necessary if Alamouti codes are used with appropriate transmission scheduling. A cross-layer design framework is then applied that optimizes routing to minimize the energy consumption and delay. For the cooperative MIMO scheme, routing is optimized based on an equivalent single-input single-out (SISO) system, where each cooperating cluster is treated as a super node. We derive the best energy-delay tradeoff curve under this optimization model and show that the cooperative MIMO approach dramatically improves energy and delay performance, especially when link layer adaptation is used.