Ohara Kerusauskas Rayel

Energy Efficiency-Spectral Efficiency Trade-Off of Transmit Antenna Selection

We investigate the energy efficiency-spectral efficiency (EE-SE) trade-off of transmit antenna selection/maximum ratio combining (TAS) scheme. A realistic power consumption model (PCM) is considered, and it is shown that using TAS can provide significant energy savings when compared to multiple-input multiple-output (MIMO) in the low to medium SE region, regardless the number of antennas, as well as outperform transmit beamforming scheme (MRT) for the entire SE range. For a fixed number of receive antennas, our results also show that the EE gain of TAS over MIMO becomes even greater as the number of transmit antennas increases. The optimal value of SE that maximizes the EE is obtained analytically, and confirmed by numerical results. Moreover, the influence of receiver correlation is also evaluated and it is shown that considering a non-realistic PCM can lead to mistakes when comparing TAS and MIMO.

Network Coding for Cooperative MIMO Vehicular Ad-Hoc Networks

In this paper, we apply nonbinary network coding to a multiple access cooperative vehicular ad hoc network (VANET), where the vehicles have independent information to transmit to a common destination. We consider that all the users in the network are provided with multiple antennas (MIMO), so that the benefits of both space-time codes and cooperative communication are used to increase the network diversity order and consequently provide more reliable communication. A Nakagami-m fading model is considered, aiming to evaluate the reliability of the proposed scheme mainly in scenarios where the channel condition is critical (sub-Rayleigh scenario with m <; 1). The network outage probability is obtained analytically, and confirmed by numerical results.

Energy Efficiency of Network Coded Cooperative Communications in Nakagami-

In this letter, we evaluate the energy efficiency of a wireless network-coded cooperative system where multiple nodes cooperatively transmit their information to a common destination. The energy consumption of the transmission and reception circuits is taken into account. It is shown that network coding can provide significant energy savings compared to direct transmission and traditional cooperation techniques. We consider a Nakagami- m fading model, so that the influence of a line-of-sight is also investigated. The optimal number of users that minimizes the energy consumption is obtained analytically, and confirmed by numerical results. Using this number to organize the nodes in clusters can provide considerable energy savings and decrease the network encoding/decoding complexity.

m

We evaluate the performance of a network-coded cooperative secondary network in a cognitive radio system under spectrum sharing constraints. The secondary network is composed of multiple sources that cooperate to transmit their own information to a common secondary destination. The outage probability is analysed under a given maximum interference constraint set by the primary network as well as to the maximum transmit power limit of the secondary sources. Moreover, we also obtain a closed-form equation for the ϵ-outage capacity, that is, the maximum information rate achieved by the secondary sources given a target outage probability. Also, we resort to the Dinkelbach algorithm in order to find the optimum number of parity packets that maximises the ϵ-outage capacity. The influence of the number of source nodes and another system parameters in the secondarys performance is also evaluated, and we show through theoretical and numerical results that cooperative communication with network coding can provide significant gains in terms of outage probability and diversity order when compared with non-cooperative or traditional cooperative. Copyright

Fading

We evaluate the secrecy outage probability of a two-user network-coded cooperative network in the presence of an eavesdropper. We show through theoretic and numerical analyses that the secrecy can be increased through the use of network coding when compared to the direct transmission and traditional cooperative techniques.

Outage performance of a network coding aided multi-user cooperative secondary network

In this paper, we consider the energy efficiency as a metric to evaluate the performance of the network coding technique when applied to a feedback-assisted multiple access cooperative network, where multiple nodes have independent information to transmit to a common destination. The energy consumption of the transmission and reception circuits is taken into account, and it is shown that only one bit of feedback may reduce the network consumption when compared schemes without feedback. The optimal number of nodes that minimizes the energy consumption of the network as a function of the distance is obtained analytically, and confirmed by numerical results.

Network-coded cooperation for a two-user wiretap channel

We analyze the area energy efficiency (AEE) of spatial multiplexing (SM) and transmit antenna selection (TAS), considering a realistic power consumption model for small base stations (BSs), which includes the power consumed by the backhaul as well as different interference attenuation levels. Our results show an optimum number of BSs for each technique that maximizes the AEE. Moreover, we also show that TAS has a larger AEE than SM when the demand for system capacity is low, while SM becomes more energy efficient when the demanded capacity is larger. Additionally, when the capacity demand and the area to be covered are fixed, the number of BSs needed to be deployed is smaller for SM than for the other techniques. Finally, the system performance in terms of AEE is shown to be strongly dependent on the amount of interference, which in turn depends on the employed interference-mitigation scheme, and on the employed power consumption model.

On the energy efficiency of feedback-assisted network coding in multiuser cooperative systems

In this chapter, an energy efficiency analysis is performed in a wireless sensor network setup considering different communication schemes, including direct non-cooperative transmission, decoded-and-forward cooperation, and network-coded cooperation. The analysis is performed considering Nakagami-m block fading, so that the influence of some line-of-sight is taken into account, while the effect of the circuitry power consumption is also considered. The theoretical and numerical results show that the use of network coding can be considerably beneficial in terms of energy efficiency and that there exists an optimal number of cooperating nodes that minimizes the energy consumption for a given distance. With network coding and with an appropriate organization of cooperating nodes into clusters, the energy efficiency is maximized, leading to energy savings of an order of magnitude with respect to the direct non-cooperative transmission.

On the Area Energy Efficiency of Multiple Transmit Antenna Small Base Stations

We evaluate the secrecy performance of a cooperative network where the destination node is wiretapped by a malicious and passive eavesdropper. We propose the application of the network coding technique as an alternative to increase the secrecy at the destination node, in a scenario without channel state information (CSI) at the transmitter side. Network coding is leveraged by assuming that the legitimate cooperative nodes are able to perform non-binary linear combinations of different frames before the transmission. Theoretic and numerical analyses show that the secrecy can be considerably increased through the use of network coding when compared to the direct transmission and traditional cooperative techniques.

Energy Efficiency of Nonbinary Network-Coded Cooperation

Presents corrections made to the paper, “Energy Efficiency-Spectral Efficiency Trade-Off of Transmit Antenna Selection” (Rayel, O.K., et al; IEEE Trans. Commun., vol. 62, no. 12, pp. 4293–4303, Dec. 2014).