Faster than Nyquist

This document provides a detailed overview of the Radio Link concepts being developed in METIS as well as a detailed analysis of the related state of the art. For each of the research topics identified for the radio link research covering flexible air interface, new waveforms, modulation and coding techniques as well as multiple access, medium access control and enablers for radio resource management, a detailed description of the aspects to be investigated will be given, going beyond the limits imposed by the systems operated today and their planned evolutions. The state of the art analysis, which is conducted for each of the research topics separately, covers current standards, their future evolutions as well as latest academic research. Elaborating on how the approaches followed in the radio link research may advance this state of the art carves a promising track towards innovative solutions addressing the challenges of future wireless communication.

Avhandlingen är uppdelad i två delar. Del I analyserar kapacitet för linjära modulationssystem med en bärvåg. Kapaciteten är en övre gräns på antalet bitar som kan överföras under en användning av kommunikationskanalen, och uppnås utav Gaussiska symboler. Den beror på den underliggande pulsen i ett linjärt modulationssystem och också signaleringshastigheten, d.v.s., hastigheten som de Gaussiska symbolerna skickas med. Målet i Del I är att studera pulsens och signaleringshastighetens påverkan på kapaciteten. Del II i avhandlingen ägnas åt Multipel Antenna System (MIMO), och mer specifikt åt linjära förkodare för MIMO system. Linjär förkodning är ett praktiskt sätt att förbättra prestandan av ett MIMO system och har studerats omfattande under de fyra senaste decennierna. I praktiska applikationer, så är symbolerna som skickas tagna från ett diskret alfabet, så som QAM, och målet är att hitta optimala linjära förkodare för ett visst prestandamått av MIMO kanalen. Designproblemet beror på prestandamåttet och även mottagarstrukturen. Svårigheten med att hitta optimala förkodare beror på problemets diskreta natur, och hittills har suboptimala lösningar mestadels föreslagits. Problemet är väl undersökt i fallet med linjära mottagare, och optimala förkodare har hittats för många olika prestandamått i detta fallet. Dock under användning av en optimal mottagare (ML mottagare), har det hittills bara föreslagits suboptimala förkodare konstruktioner. Del II i avhandlingen börjar med att föreslå nya, lågkomplexitets suboptimala förkodare, som resulterar i en låg bitfelssannolikhet (BER) hos mottagaren. Därefter utvecklas en iterativ optimeringsmetod, vilken producerar förkodare som förbättrar de hittills bästa i litteraturen. De erhållna förkodarna uppvisar en viss struktur, som därefter analyseras och visas vara optimal för stora symbol alfabet. Dessa resultat visas också vara tillämpbara för små, praktiska symbol alfabet, och ger upphov till nya sätt att konstruera förkodare med utmärkt prestanda för ML mottagare.

We investigate faster-than-Nyquist modulation based on short finite pulses over the AWGN channel. We consider several pulse shapes and compare their in- formation rates for several system setups. We com- pare the effect of increasing the alphabet size ver- sus of increasing the signaling rate. The outcome is that for these pulses the FTN symbol rate is of greater importance than the alphabet size. Finally we test some concatenated coding schemes where faster- than-Nyquist modulation constitutes the innermost encoder; the outcome is very good.

Avhandlingen är uppdelad i två delar. Del I analyserar kapacitet för linjära modulationssystem med en bärvåg. Kapaciteten är en övre gräns på antalet bitar som kan överföras under en användning av kommunikationskanalen, och uppnås utav Gaussiska symboler. Den beror på den underliggande pulsen i ett linjärt modulationssystem och också signaleringshastigheten, d.v.s., hastigheten som de Gaussiska symbolerna skickas med. Målet i Del I är att studera pulsens och signaleringshastighetens påverkan på kapaciteten. Del II i avhandlingen ägnas åt Multipel Antenna System (MIMO), och mer specifikt åt linjära förkodare för MIMO system. Linjär förkodning är ett praktiskt sätt att förbättra prestandan av ett MIMO system och har studerats omfattande under de fyra senaste decennierna. I praktiska applikationer, så är symbolerna som skickas tagna från ett diskret alfabet, så som QAM, och målet är att hitta optimala linjära förkodare för ett visst prestandamått av MIMO kanalen. Designproblemet beror på prestandamåttet och även mottagarstrukturen. Svårigheten med att hitta optimala förkodare beror på problemets diskreta natur, och hittills har suboptimala lösningar mestadels föreslagits. Problemet är väl undersökt i fallet med linjära mottagare, och optimala förkodare har hittats för många olika prestandamått i detta fallet. Dock under användning av en optimal mottagare (ML mottagare), har det hittills bara föreslagits suboptimala förkodare konstruktioner. Del II i avhandlingen börjar med att föreslå nya, lågkomplexitets suboptimala förkodare, som resulterar i en låg bitfelssannolikhet (BER) hos mottagaren. Därefter utvecklas en iterativ optimeringsmetod, vilken producerar förkodare som förbättrar de hittills bästa i litteraturen. De erhållna förkodarna uppvisar en viss struktur, som därefter analyseras och visas vara optimal för stora symbol alfabet. Dessa resultat visas också vara tillämpbara för små, praktiska symbol alfabet, och ger upphov till nya sätt att konstruera förkodare med utmärkt prestanda för ML mottagare.

This document provides a detailed overview of the Radio Link concepts being developed in METIS as well as a detailed analysis of the related state of the art. For each of the research topics identified for the radio link research covering flexible air interface, new waveforms, modulation and coding techniques as well as multiple access, medium access control and enablers for radio resource management, a detailed description of the aspects to be investigated will be given, going beyond the limits imposed by the systems operated today and their planned evolutions. The state of the art analysis, which is conducted for each of the research topics separately, covers current standards, their future evolutions as well as latest academic research. Elaborating on how the approaches followed in the radio link research may advance this state of the art carves a promising track towards innovative solutions addressing the challenges of future wireless communication.

This deliverable represents the final report on the METIS radio link research. It provides a comprehensive and self-contained summary of all investigated technology components (TeCs), including evaluation results and conclusions on their potential for 5G. The METIS radio link research covers three main areas, which are considered key aspects for developing a self-contained air interface design for 5G: 1) Flexible air interface, 2) Waveforms, coding & modulation and transceiver design and 3) Multiple access, Medium Access Control (MAC) and Radio Resource Management (RRM). TeCs with similar research context and objectives have been grouped into clusters, whereof five have been selected as the most promising for 5G systems: From research area 1, TeC clusters providing key enablers for an air interface for ultra-dense networks (UDN) and for moving networks; from research area 2, multi-carrier transmission schemes with filtering; and from research area 3, novel access schemes for massive...

In this paper, we propose several precoding methods to reduce the interference caused by Faster-Than-Nyquist (FTN) signaling for Orthogonal Frequency Division Multiplexing Offset Quadrature Amplitude Modulation (OFDM/OQAM). The proposed precoders are combined with an FTN-OFDM/OQAM modulator to pre-cancel the interference at the transmitter side. An iterative receiver for each precoding scheme is also presented. With the simulations, we show that the convergence speed of the FTN-OFDM/OQAM transceiver increases with the proposed precoders.

In this paper, we propose several precoding methods to reduce the interference caused by Faster-Than-Nyquist (FTN) signaling for Orthogonal Frequency Division Multiplexing Offset Quadrature Amplitude Modulation (OFDM/OQAM). The proposed precoders are combined with an FTN-OFDM/OQAM modulator to pre-cancel the interference at the transmitter side. An iterative receiver for each precoding scheme is also presented. With the simulations, we show that the convergence speed of the FTN-OFDM/OQAM transceiver increases with the proposed precoders.

This document provides intermediate results of the concepts being developed in the radio link research of METIS. For each of the technology components (TeC) within the technology component clusters (TeCC), covering flexible air interface, new waveforms, modulation and coding techniques as well as multiple access, medium access control and enablers for radio resource management, key findings and conclusions collected so far are summarized in section 2. Continuative descriptions and research outcomes are given in the annex and referred publications. The results presented here will be extended in the further progress of the project, and they will be used in the next phase of the project to develop and refine the overall METIS system concept instantiated by the horizontal topics. The suitability of the single technology components for the overall system design being able to meet the wide range of requirements for 5G will then be evaluated.

We investigate the performance of concatenated coding schemes based on Faster Than Nyquist (FTN) signaling over the AWGN channel. We test both serial and parallel concatenations. In serial concatenation the FTN signaling is considered as the inner encoder and the outer code is a rate b/c convolutional code. In parallel schemes we use two parallel Gaussian channels and transmit FTN pulse trains in both; here a precoding device turns out to be crucial. The convergence behaviour is analysed using EXIT charts. The overall spectral density of the schemes varies but is roughly 1-2 bit/s/Hz. The results, in terms of needed E b /N0 for reliable communication versus spectral density, are very good.

We investigate faster-than-Nyquist modulation based on short finite pulses over the AWGN channel. We consider several pulse shapes and compare their in- formation rates for several system setups. We com- pare the effect of increasing the alphabet size ver- sus of increasing the signaling rate. The outcome is that for these pulses the FTN symbol rate is of greater importance than the alphabet size. Finally we test some concatenated coding schemes where faster- than-Nyquist modulation constitutes the innermost encoder; the outcome is very good.

This document provides a detailed overview of the Radio Link concepts being developed in METIS as well as a detailed analysis of the related state of the art. For each of the research topics identified for the radio link research covering flexible air interface, new waveforms, modulation and coding techniques as well as multiple access, medium access control and enablers for radio resource management, a detailed description of the aspects to be investigated will be given, going beyond the limits imposed by the systems operated today and their planned evolutions. The state of the art analysis, which is conducted for each of the research topics separately, covers current standards, their future evolutions as well as latest academic research. Elaborating on how the approaches followed in the radio link research may advance this state of the art carves a promising track towards innovative solutions addressing the challenges of future wireless communication.

— This paper proposes a novel and simple orthogonal faster than Nyquist (OFTN) data transmission and detection approach for a single input multiple output (SIMO) system. It is assumed that the signal having a bandwidth B is transmitted through a wireless channel having L multipath components. Under this assumption, the current paper provides novel OFTN transmission and symbol-by-symbol detection approach that exploits the multiplexing gain obtained by the inherent characteristics of multipath components of wideband channels. In doing so, the proposed design achieves a higher transmission rate than the existing orthogonal frequency division multiplexing (OFDM) approach. It is also shown that the capacity gap between the proposed approach and that of OFDM increases as the number of receiver antennas increases for fixed L. The superiority of the proposed approach has been shown theoretically and confirmed via numerical simulations.