EMF-aware cell selection in heterogeneous cellular networks

The growing concern on the exposure of users to the electromagnetic field (EMF) has recently brought new challenges to the mobile research community. In this letter, we propose a novel cell association framework for heterogeneous cellular networks (HetNets), which aims to balance the load amongst heterogeneous cells so as to improve the resource usage and to increase the user satisfaction in terms of both data rate and EMF exposure. We model the cell selection problem as a General Assignment Problem (GAP) and we present two heuristic algorithms, which solve it with limited complexity. Our analysis shows that the proposed solutions lead to notable improvements with respect to legacy association schemes.This papers reports work undertaken in the context of the project LEXNET. LEXNET is a project supported by the European Commission in the 7th Framework Programme (Grant Agreement n. 318273)

Technology Roadmap for Beyond 5G Wireless Connectivity in D-band

International audienceWireless communication in millimeter wave bands, namely above 20 GHz and up to 300 GHz is foreseen as a key enabler technology for the next generation of wireless systems. The huge available bandwidth is contemplated to achieve high data rate wireless communications, and hence, to fulfill the requirements of future wireless networks. Several Beyond 5G applications are considered for these systems: high capacity back-haul, enhanced hot-spot kiosk as well as short-range Device-to-Device communications. In this paper we propose to discuss the trade-offs between scenario requirements and current silicon technologies limits to draw a technology roadmap for the next generation of wireless connectivity in D-band

4MORE: An advanced MIMO downlink MC-CDMA system

ABSTRACT The IST 4MORE project defines a multicarrier code division multiple access (MC-CDMA) radio system with multiple mobile users and advances this one step towards implementation through the design of a System on Chip (SoC) for a 4G terminal employing multiple antennas, based on MC-CDMA. In this contribution we present results of the simulated downlink scenario, which is the base for the designed demonstrator. We cover different channels, various modulation schemes, coarse time synchronization, carrier frequency offset tracking and finally the effect and countermeasures which are needed for RF impairments. The implemented air interface offers transmitting 5.5 bits/s/Hz over two spatial parallel multiplexed data streams

UNII-MAC protocol: Design and evaluation for 5G ultra-dense small cell networks operating in 5 GHz unlicensed spectrum

International audienceUltra-densification and efficient spectrum utilization are key features for the next 5G wireless networks to address the well-known challenges of high capacity demands and mobile data traffic explosion. In this article, a physical layer and a medium access control (MAC) sublayer are presented for small cells to operate in the 5 GHz unlicensed national information infrastructure (UNII) band. The physical layer is based on filter bank multi-carrier modulation able to achieve better spectral efficiency and access flexibility. The MAC protocol is based on beacon-enabled superframe consisting of scheduled and contention access schemes. The proposed UNII-MAC design relies on a listen-before-talk (LBT) procedure in order to comply with ETSI regulations and to fairly coexist with neighboring systems sharing the same band. The performance of the UNII-MAC is then evaluated in dense indoor/outdoor deployment scenarios under various parameters and traffic patterns. Moreover, the coexistence between UNII-MAC and WiFi systems is reported. Based on the obtained results, we provide recommendations for 5G small cell deployment in dense environments

MAC design for 5G dense networks based on FBMC modulation

International audienceThe fifth generation (5G) of wireless networks is currently under investigation in order to address the well-known challenges of the high capacity demands and traffic volume. The promising solutions to meet these targets can be achieved through ultra-densification, efficient use of spectrum and advanced filtered modulation techniques. In this paper, we present an enhanced MAC protocol for 5G small cells operating at 5 GHz and assuming an FBMC physical layer. The proposed MAC design consists of scheduled-based and contention-based access schemes and involves a listen before talk (LBT) procedure to comply with ETSI regulations. The performance of the proposed FBMC-MAC design is then evaluated in dense deployment scenarios under different PHY/MAC parameter settings. Moreover, we study the performance of FBMC-MAC systems in the context of coexistence with WiFi systems

Waveform contenders for 5G: Description, analysis and comparison

International audience5G will have to cope with a high degree of heterogeneity in terms of services and requirements. Among these latter, flexible and efficient use of all available non-contiguous spectra for different network deployment scenarios is one challenge for the future 5G. To maximize spectrum efficiency, a flexible 5G air interface technology capable of mapping various services to the best suitable combinations of frequency and radio resources will also be required. In this work, a fair comparison of several 5G waveform candidates (UFMC, FBMC-OQAM, and FBMC-QAM) is proposed under a common framework. Spectral efficiency, power spectral density, peak to average power ratio and performance in terms of bit error rate under various realistic channel conditions are assessed. The waveforms are then compared in an asynchronous multiuser uplink transmission. Based on these results, in order to increase the spectral efficiency, a bit loading algorithm is proposed to cope with the non-uniform distribution of the interference across the carriers. The benefits of these new waveforms for the foreseen 5G use cases are clearly highlighted. It is also stressed that some concepts still need to be improved to achieve the full range of expected benefits of 5G

Air Interface Challenges and Solutions for future 6G Networks

5G networks are expected to be deployed in 2020 and are considered as a global game changer from a technological, economic, societal and environmental perspective with very aggressive performance levels in terms of latency, energy efficiency, wireless broadband capacity, elasticity, etc. Many experts say that the next big step for cellular networks is not 5G but its cloudifica-tion that will support the explosion of radically new services and applications ranging from immersive five-sense media to ambient sensing intelligence and a pervasive introduction of artificial intelligence. In our vision, the next generation of wireless systems will transform the 5G service-oriented networks into user and machine ad-hoc dynamic (re)configuration of network slices. This will be enabled by software-defined end-to-end solutions from the core to the radio access network, including the air interface as well as the RF and antenna systems which are envisioned as one of the keys to meet the user/service requirements. Users and machines will be indeed able to dynamically (re)configure network slices thanks to intelligent personal edges. This paper presents our perspective of the 6G air interface and raise the concept of software defined artificial intelligence and air interface (SD-AI 2) as a framework of 6G air interface. This concept is an extension of the one initially proposed for 5G [1]. Instead of a global optimized air interface, we envisage to bring agility and flexibility to air interface with the help of artificial intelligence and learning techniques to improve efficiency. The paper describes the proposed context and highlights the technical challenges at different levels

Block-filtered OFDM: A novel waveform for future wireless technologies

International audienceThe forthcoming fifth generation of mobile technology (5G) will be designed to satisfy the demands of 2020 and beyond. 5G does not just promise a huge increase in terms of data rates and capacity but it also targets new kind of use cases like Internet of Things or vehicular communications. The currently deployed 4G technology does not provide enough network capabilities to support this wide diversity of applications which has motivated the research on alternative waveforms. In this article, a new promising modulation scheme is introduced: Block-Filtered OFDM (BF-OFDM). The proposed waveform demonstrates an excellent frequency localization and can straightforwardly be integrated with the OFDM know-how and LTE principles. Besides, the proposed waveform relies on a receiver similar to the one used in CP-OFDM. BF-OFDM systems are also scalable, which is an interesting feature in order to steer the network capabilities on demand

Filter design for 5G BF-OFDM waveform

International audienceA flexible and efficient use of the frequency resource is a key challenge for future wireless technologies. The new requirements are not satisfied by the CP-OFDM which has motivated the research on alternative waveforms. Recently, Block-Filtered OFDM modulation scheme has been proposed. This waveform addresses most of the CP-OFDM's drawbacks at the price of a slight complexity increase of the transmitter. The scheme is based on a filter-bank, a precoding stage that ensures the Near Perfect Reconstruction property and a pre-compensation stage which avoids filtering at the receiver. In this paper, the filter specifications for BF-OFDM are derived and an optimization method based on self-interference rejection is proposed. Optimized filter shape can provide up to 70 dB of Signal-to-Interference Ratio which justifies the Near Perfect Reconstruction property with an enhanced spectral confinement and no channel performance degradation