Suchergebnisse

The problem of resource allocation in two-way relay network is considered in this paper. The cognitive radio (CR) context is tackled where a amplify and forward (AF) OFDM-based dual-hop multiple relay system is investigated. The joint allocation of subcarrier pairing, relay selection and power allocation is performed under both interference and individual power constraints where the target is to maximize the achievable data rate of the network. The dual decomposition is adopted to obtain the optimal solution. Two sub-optimal schemes are proposed also to reduce the computational complexity of the optimal scheme. Simulations are presented to compare the performance of the optimal scheme with that of the proposed sub-optimal schemes. ; Grant numbers : This work is funded by the Catalan Government (2009SGR0891).© 2014 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.

In this paper, the problem of cross-layer design of the link scheduling and flow control is studied in hybrid terrestrial-satellite wireless backhauling network. Considering network limitations and requirements, the target is to minimize the traffic delivery time by deciding the active backhauling links that can transmit simultaneously. Additionally, the proposed scheme provides a way to utilize the satellite links efficiently in order to provide the required link failure resiliency and traffic off-loading capability. Simulation results quantify the benefits of using the satellite links in cases of link failure and traffic congestion. ; Grant numbers : This work is supported by the Spanish Government under project ELISA (TEC2014-59255-C3-1-R).© 2017 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.

Caching is an enabler to avoid congestion and delay in the backhaul links of future 5G networks. The basic idea behind this concept consists in estimating the content that would be most likely requested by the end users served by each edge node and, after that, make a pro-active placement of those files during the traffic off-peak hours. Optical wired/wireless terrestrial links support a high point-to-point data rate but, when the same content needs to reach different destinations, parallel unicast transmissions are needed. On the other hand, satellite systems provide a lower link-level data rate but can easily implement a multicast transmission due to their wide-area coverage. In this paper, a resource allocation strategy that determines the most convenient way to transport the different content using both terrestrial (optical) and satellite (radio) technologies is proposed. Simulation results show that the placement time can be notably reduced in a hybrid terrestrial-satellite backhaul network, particularly in case of bad weather that impacts the data rate of the wireless optical links. The effect of the file popularity distribution and the number of 5G edge nodes on the delivery time is also studied in detail. ; Grant numbers : Project TERESA-TEC2017-90093-C3-1-R (AEI/FEDER, UE), and by the Catalan government under grant 2017 SGR 1479. © 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.

Interference alignment (IA) has been proposed to optimally manage the interference aiming at providing the maximum degrees of freedom for multiuser interference channels. Therefore, IA has been used in cognitive radio (CR) systems to perform resource management in order to improve the throughput of the OFDM/FBMC based MIMO CR systems. In this work, a sub-optimal IA based power loading method is proposed for OFDM/FBMC based MIMO CR systems to approach the optimal approach with fewer complexity. In the proposed algorithm, all secondary users are enabled to share the available spectrum on the base of IA technique without affecting the quality-of-service of the primary system. Furthermore, spectral efficiency comparison between MIMO-OFDM and MIMO-FBMC is presented. Simulation results show that IA based power loading achieves a significant sum-rate increase of CR systems compared to traditional orthogonal multiple access techniques. Additionally, IA based power loading achieves better sum-rate improvement with FBMC than OFDM physical layer. ; Grant numbers : This work is funded by the Catalan Government (2009SGR0891). © 2014 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.

In this paper, we investigate the problem of crosslayer design of the link scheduling, frequency assignment and flow control in hybrid terrestrial-satellite wireless backhauling networks. Considering network limitations and requirements, the target is to maximize the traffic that can be delivered by the network in a given period of time by deciding the active backhauling links that can transmit simultaneously over the different frequencies as well as the amount of traffic that should be forwarded in these active links. Due to the interference between the different links, the problem is NP-hard and an efficient scheme is developed to estimate the interference, determine the link capacity lower bound, and obtain the final allocation. The proposed algorithm is simulated in a realistic topology and assuming parameters of practical interest to reveal the advantage of the developed scheme. ; Grant numbers : This work is supported by the Spanish Government under project ELISA (TEC2014-59255-C3-1-R).© 2017 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.

The advent of a new generation of wireless cellular communication networks (5G) is currently being discussed both in research and standardization, while 4G is continuously evolving. Within the overall 5GPPP framework, FANTASTIC-5G is the project dealing with the design of the multi-service air interface for below 6 GHz. Ultimate target of the project is to allow the system to adapt to any means arising from diverse service requirements and device capabilities, various deployment and environment settings and mobility levels. Additionally, the ambition of the project is to have an impact to standardization. Therefore, we focus on technologies being relevant for standardization instead of proprietary elements. This paper provides some insights on the project itself and on the concepts being worked on. ; Grant number : This work has been performed in the framework of the Horizon 2020 project FANTASTIC-5G (ICT-671660) receiving funds from the European Union.© 2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.