Channel Equalization in Fast-Convolution Filter Bank based Receivers for Professional Mobile Radio

Abstract-Fast convolution processing has recently been proposed as an efficient approach for implementing filter bank multicarrier systems with good spectral containment and high flexibility in adjusting the subchannel bandwidths and center frequencies. These features make fast convolution filter banks (FC-FBs) a particularly interesting choice for multicarrier transmission in challenging radio scenarios like dynamic spectrum access, cognitive radio, and fragmented spectrum use. In this contribution, the target is to compare the performance of the time-domain equalizer with the frequency-domain equalizer implemented through subcarrier processing in LTE-like multicarrier systems. It is shown that integrating the equalization functions with the FC-FB processing leads to an efficient overall implementation in terms of performance and computational complexity

Efficient Fast-Convolution-Based Waveform Processing for 5G Physical Layer

This paper investigates the application of fast-convolution (FC) filtering schemes for flexible and effective waveform generation and processing in the fifth generation (5G) systems. FC-based filtering is presented as a generic multimode waveform processing engine while, following the progress of 5G new radio standardization in the Third-Generation Partnership Project, the main focus is on efficient generation and processing of subband-filtered cyclic prefix orthogonal frequency-division multiplexing (CP-OFDM) signals. First, a matrix model for analyzing FC filter processing responses is presented and used for designing optimized multiplexing of filtered groups of CP-OFDM physical resource blocks (PRBs) in a spectrally well-localized manner, i.e., with narrow guardbands. Subband filtering is able to suppress interference leakage between adjacent subbands, thus supporting independent waveform parametrization and different numerologies for different groups of PRBs, as well as asynchronous multiuser operation in uplink. These are central ingredients in the 5G waveform developments, particularly at sub-6-GHz bands. The FC filter optimization criterion is passband error vector magnitude minimization subject to a given subband band-limitation constraint. Optimized designs with different guardband widths, PRB group sizes, and essential design parameters are compared in terms of interference levels and implementation complexity. Finally, extensive coded 5G radio link simulation results are presented to compare the proposed approach with other subband-filtered CP-OFDM schemes and time-domain windowing methods, considering cases with different numerologies or asynchronous transmissions in adjacent subbands. Also the feasibility of using independent transmitter and receiver processing for CP-OFDM spectrum control is demonstrated

Rapid prototyping and validation of FS-FBMC dynamic spectrum radio with simulink and ZynqSDR

This paper presents the research carried out in developing and targeting a novel real-time Dynamic Spectrum Access (DSA) Frequency Spread Filter Bank Multicarrier (FS-FBMC) transmitter prototype to programmable ‘ZynqSDR’ Software Defined Radio (SDR) hardware, and introduces a series of experiments used to validate the design’s ‘cognitive’ DSA capabilities. This transmitter is a proof of concept, that uses DSA techniques to enable Secondary Users (SUs) to access the band traditionally used for FM Radio broadcasting (88-108 MHz), and establish data communication channels in vacant parts of the FM Radio Primary User (PU) spectrum using a multicarrier modulation scheme with a Non Contiguous (NC) channel mask. Once implemented on the hardware, the transmitter is subjected to various FM Radio environments sampled from around Central Scotland, and it is demonstrated that it can dynamically adapt its NC transmitter mask in real time to protect the FM Radio signals it detects. A video is presented of this dynamic on-hardware spectral reconfiguration, and the reader is encouraged to view the video to appreciate the responsiveness of the design. An investigation into potential FBMC guardband sizes is carried out, with initial findings indicating a guardband of 200 kHz (either side of an FM Radio station) is required in order to prevent interference with the PUs. This paper also demonstrates the capabilities of the MATLAB®/ Simulink ZynqSDR workflow, and provides a case study and reference design that we feel other researchers working in this field can benefit from

Enhanced Multicarrier Techniques for Professional Ad-Hoc and Cell-Based Communications (EMPhAtiC) Document Number D3.3 Reduction of PAPR and non linearities effects

Livrable d'un projet Européen EMPHATICLike other multicarrier modulation techniques, FBMC suffers from high peak-to-average power ratio (PAPR), impacting its performance in the presence of a nonlinear high power amplifier (HPA) in two ways. The first impact is an in-band distortion affecting the error rate performance of the link. The second impact is an out-of-band effect appearing as power spectral density (PSD) regrowth, making the coexistence between FBMC based broad-band Professional Mobile Radio (PMR) systems with existing narrowband systems difficult to achieve. This report addresses first the theoretical analysis of in-band HPA distortions in terms of Bit Error Rate. Also, the out-of band impact of HPA nonlinearities is studied in terms of PSD regrowth prediction. Furthermore, the problem of PAPR reduction is addressed along with some HPA linearization techniques and nonlinearity compensation approaches

Filtered Multicarrier Transmission

Orthogonal frequency‐division multiplexing (OFDM) has been adopted as the waveform of choice in the existing and emerging broadband wireless communication systems for a number of advantages it can offer. Nevertheless, investigations of more advanced multicarrier transmission schemes have continued with the aim of eliminating or mitigating its essential limitations. This article discusses multicarrier schemes with enhanced spectrum localization, which manage to reduce the spectral sidelobes of plain OFDM that are problematic in various advanced communication scenarios. These include schemes for enhancing the OFDM waveform characteristics through additional signal processing as well as filter‐bank multicarrier (FBMC) waveforms utilizing frequency‐selective filter banks instead of plain (inverse) discrete Fourier transform processing for waveform generation and demodulation.acceptedVersionPeer reviewe

Enhanced Spectrum Sensing Techniques for Cognitive Radio Systems

Due to the rapid growth of new wireless communication services and applications, much attention has been directed to frequency spectrum resources. Considering the limited radio spectrum, supporting the demand for higher capacity and higher data rates is a challenging task that requires innovative technologies capable of providing new ways of exploiting the available radio spectrum. Cognitive radio (CR), which is among the core prominent technologies for the next generation of wireless communication systems, has received increasing attention and is considered a promising solution to the spectral crowding problem by introducing the notion of opportunistic spectrum usage. Spectrum sensing, which enables CRs to identify spectral holes, is a critical component in CR technology. Furthermore, improving the efficiency of the radio spectrum use through spectrum sensing and dynamic spectrum access (DSA) is one of the emerging trends. In this thesis, we focus on enhanced spectrum sensing techniques that provide performance gains with reduced computational complexity for realistic waveforms considering radio frequency (RF) impairments, such as noise uncertainty and power amplifier (PA) non-linearities. The first area of study is efficient energy detection (ED) methods for spectrum sensing under non-flat spectral characteristics, which deals with relatively simple methods for improving the detection performance. In realistic communication scenarios, the spectrum of the primary user (PU) is non-flat due to non-ideal frequency responses of the devices and frequency selective channel conditions. Weighting process with fast Fourier transform (FFT) and analysis filter bank (AFB) based multi-band sensing techniques are proposed for overcoming the challenge of non-flat characteristics. Furthermore, a sliding window based spectrum sensing approach is addressed to detect a re-appearing PU that is absent in one time and present in other time. Finally, the area under the receiver operating characteristics curve (AUC) is considered as a single-parameter performance metric and is derived for all the considered scenarios. The second area of study is reduced complexity energy and eigenvalue based spectrum sensing techniques utilizing frequency selectivity. More specifically, novel spectrum sensing techniques, which have relatively low computational complexity and are capable of providing accurate and robust performance in low signal-to-noise ratio (SNR) with noise uncertainty, as well as in the presence of frequency selectivity, are proposed. Closed-form expressions are derived for the corresponding probability of false alarm and probability of detection under frequency selectivity due the primary signal spectrum and/or the transmission channel. The offered results indicate that the proposed methods provide quite significant saving in complexity, e.g., 78% reduction in the studied example case, whereas their detection performance is improved both in the low SNR and under noise uncertainty. Finally, a new combined spectrum sensing and resource allocation approach for multicarrier radio systems is proposed. The main contribution of this study is the evaluation of the CR performance when using wideband spectrum sensing methods in combination with water-filling and power interference (PI) based resource allocation algorithms in realistic CR scenarios. Different waveforms, such as cyclic prefix based orthogonal frequency division multiplexing (CP-OFDM), enhanced orthogonal frequency division multiplexing (E-OFDM) and filter bank based multicarrier (FBMC), are considered with PA nonlinearity type RF impairments to see the effects of spectral leakage on the spectrum sensing and resource allocation performance. It is shown that AFB based spectrum sensing techniques and FBMC waveforms with excellent spectral containment properties have clearly better performance compared to the traditional FFT based spectrum sensing techniques with the CP-OFDM. Overall, the investigations in this thesis provide novel spectrum sensing techniques for overcoming the challenge of noise uncertainty with reduced computational complexity. The proposed methods are evaluated under realistic signal models

Massive MIMO channel modelling for 5G wireless communication systems

Massive Multiple-Input Multiple-Output (MIMO) wireless communication systems, equipped with tens or even hundreds of antennas, emerge as a promising technology for the Fifth Generation (5G) wireless communication networks. To design and evaluate the performance of massive MIMO wireless communication systems, it is essential to develop accurate, flexible, and efficient channel models which fully reflect the characteristics of massive MIMO channels. In this thesis, four massive MIMO channel models have been proposed. First, a novel non-stationary wideband multi-confocal ellipse Two-Dimensional (2-D) Geometry Based Stochastic Model (GBSM) for massive MIMO channels is proposed. Spherical wavefront is assumed in the proposed channel model, instead of the plane wavefront assumption used in conventional MIMO channel models. In addition, the Birth-Death (BD) process is incorporated into the proposed model to capture the dynamic properties of clusters on both the array and time axes. Second, we propose a novel theoretical non-stationary Three-Dimensional (3-D) wideband twin-cluster channel model for massive MIMO communication systems with carrier frequencies in the order of gigahertz (GHz). As the dimension of antenna arrays cannot be ignored for massive MIMO, nearfield effects instead of farfield effects are considered in the proposed model. These include the spherical wavefront assumption and a BD process to model non-stationary properties of clusters such as cluster appearance and disappearance on both the array and time axes. Third, a novel Kronecker Based Stochastic Model (KBSM) for massive MIMO channels is proposed. The proposed KBSM can not only capture antenna correlations but also the evolution of scatterer sets on the array axis. In addition, upper and lower bounds of KBSM channel capacities in both the high and low Signal-to-Noise Ratio (SNR) regimes are derived when the numbers of transmit and receive antennas are increasing unboundedly with a constant ratio. Finally, a novel unified framework of GBSMs for 5G wireless channels is proposed. The proposed 5G channel model framework aims at capturing key channel characteristics of certain 5G communication scenarios, such as massive MIMO systems, High Speed Train (HST) communications, Machine-to-Machine (M2M) communications, and Milli-meter Wave (mmWave) communications

Device-to-device communications for 5G Radio Access Networks

Nowadays it is very popular to share video clips and images to one’s social network in the proximity. Direct device-to-device (D2D) communication is one of the means to respond to this requirement. D2D offers users improved end-to-end latency times, and additionally can provide higher data rates. At the same time the overall cellular network congestion decreases. D2D is also known as Proximity Services (ProSe). LTE is missing direct D2D communication. Currently D2D for 5G is standardised in the 3rd Generation Partnership Project (3GPP) Releases 12, and in parallel Mobile and wireless communications Enablers for the Twenty-twenty Information Society (METIS) project has D2D as one of its research topics. Multiple articles have been published about D2D communication. This thesis is a literature based thesis following D2D communication in 5G literature. The scope is to describe similarities and differences found in Technical Reports and Technical Specifications of the 3GPP Release 12, in deliverables written in METIS project and in some selected D2D related publications about D2D communications. 3GPP Release 12 concentrates on ProSe at least for public safety. ProSe communication out-of-coverage is only for public safety purposes. METIS provides multiple solutions for diverse D2D topics, for example, device discovery, radio resource management, mobility management and relaying. METIS provides solutions for D2D communication not yet mature enough for development and implementation but which might be realized in the future.Nykyisin on suosittua lähettää lyhyitä videoita tai kuvia läheisyydessä oleville ystäville. Laitteiden välinen suora kommunikointi eli D2D-viestintä tuo ratkaisun tähän vaatimukseen. D2D-viestinnän ansiosta viive lyhenee ja lisäksi siirtonopeudet kasvavat. Samaan aikaan koko verkon kuormitus vähenee. Suora kahden laitteen välinen kommunikointi puuttuu LTE:stä. Tällä hetkellä 3GPP Release 12 standardisoi suoraa kahden laitteen välistä kommunikointia. Samanaikaisesti Mobile and wireless communications Enablers for the Twenty-twenty Information Society (METIS) –projektin yhtenä tutkimuskohteenaan on kahden laitteen välinen suora kommunikointi, Lisäksi on lukuisia julkaisuja liittyen D2D-viestintään. Tämä diplomityö perustuu kirjallisuuteen. Sen tavoitteena on selvittää, miten kahden laitteen välistä suoraa kommunikointia on kuvattu 3GPP Release 12:ta teknisissä spesifikaatioissa, METIS-projektin julkaisuissa sekä muutamassa valitussa tieteellisessä julkaisussa. Tavoitteena on selvittää D2D-viestinnän yhtäläisyyksiä sekä poikkeamia. 3PGG Release 12 standardointi keskittyy D2D-viestinnän käyttöön ainakin julkisessa pelastustyössä. D2D-viestinnän tulee ainakin julkisessa pelastustyössä toimia myös siellä missä matkapuhelinverkko ei toimi tai sitä ei ole olemassa. METIS tarjoaa useita ratkaisuja D2D-viestinnän eri osa-alueille, esimerkiksi laitteiden tunnistamiseen, resurssien hallintaan, liikkuvuuden hallintaa ja viestien edelleen lähettämiseen. METIS-projekti on tuottanut D2D-viestinnän ratkaisuja, joiden toteuttaminen on järkevää ja mahdollista vasta tulevaisuudessa

5G innovation opportunities-- A discussion paper

On the shaping of 5G technologies and networks, scope for wider service and applications innovation and UK strengths and opportunities

Spectrum Sharing, Latency, and Security in 5G Networks with Application to IoT and Smart Grid

The surge of mobile devices, such as smartphones, and tables, demands additional capacity. On the other hand, Internet-of-Things (IoT) and smart grid, which connects numerous sensors, devices, and machines require ubiquitous connectivity and data security. Additionally, some use cases, such as automated manufacturing process, automated transportation, and smart grid, require latency as low as 1 ms, and reliability as high as 99.99\%. To enhance throughput and support massive connectivity, sharing of the unlicensed spectrum (3.5 GHz, 5GHz, and mmWave) is a potential solution. On the other hand, to address the latency, drastic changes in the network architecture is required. The fifth generation (5G) cellular networks will embrace the spectrum sharing and network architecture modifications to address the throughput enhancement, massive connectivity, and low latency. To utilize the unlicensed spectrum, we propose a fixed duty cycle based coexistence of LTE and WiFi, in which the duty cycle of LTE transmission can be adjusted based on the amount of data. In the second approach, a multi-arm bandit learning based coexistence of LTE and WiFi has been developed. The duty cycle of transmission and downlink power are adapted through the exploration and exploitation. This approach improves the aggregated capacity by 33\%, along with cell edge and energy efficiency enhancement. We also investigate the performance of LTE and ZigBee coexistence using smart grid as a scenario. In case of low latency, we summarize the existing works into three domains in the context of 5G networks: core, radio and caching networks. Along with this, fundamental constraints for achieving low latency are identified followed by a general overview of exemplary 5G networks. Besides that, a loop-free, low latency and local-decision based routing protocol is derived in the context of smart grid. This approach ensures low latency and reliable data communication for stationary devices. To address data security in wireless communication, we introduce a geo-location based data encryption, along with node authentication by k-nearest neighbor algorithm. In the second approach, node authentication by the support vector machine, along with public-private key management, is proposed. Both approaches ensure data security without increasing the packet overhead compared to the existing approaches