Mitigation of impulsive noise for SISO and MIMO G.fast system

To address the demand for high bandwidth data transmission over telephone transmission lines, International Telecommunication Union (ITU) has recently completed the fourth generation broadband (4GBB) copper access network technology, known as G.fast. Throughout this thesis, extensively investigates the wired broadband G.fast coding system and the novel impulsive noise reduction technique has been proposed to improve the performance of wired communications network in three different scenarios: single-line Discrete Multiple Tone (DMT)- G.fast system; a multiple input multiple-output (MIMO) DMTG.fast system, and MIMO G.fast system with different crosstalk cancellation methods. For each of these scenarios, however, Impulsive Noise (IN) is considered as the main limiting factor of performance system. In order to improve the performance of such systems, which use higher order QAM constellation such as G.fast system, this thesis examines the performance of DMT G.fast system over copper channel for six different higher signal constellations of M = 32, 128, 512, 2048, 8192 and 32768 in presence of IN modelled as the Middleton Class A (MCA) noise source. In contrast to existing work, this thesis presents and derives a novel equation of Optimal Threshold (OT) to improve the IN frequency domain mitigation methods applied to the G.fast standard over copper channel with higher QAM signal constellations. The second scenario, Multi-Line Copper Wire (MLCW) G.fast is adopted utilizing the proposed MLCW Chen model and is compared to a single line G-fast system by a comparative analysis in terms of Bit-Error-Rate(BER) performance of implementation of MLCW-DMT G.fast system. The third scenario, linear and non-linear crosstalk crosstalk interference cancellation methods are applied to MLCW G.fas and compared by a comparative analysis in terms of BER performance and the complexity of implementation.University of Technology for choosing me for their PhD scholarship and The Higher Committee For Education Development in Iraq(HCED

Bandwidth Compressed Waveform and System Design for Wireless and Optical Communications: Theory and Practice

This thesis addresses theoretical and practical challenges of spectrally efficient frequency division multiplexing (SEFDM) systems in both wireless and optical domains. SEFDM improves spectral efficiency relative to the well-known orthogonal frequency division multiplexing (OFDM) by non-orthogonally multiplexing overlapped sub-carriers. However, the deliberate violation of orthogonality results in inter carrier interference (ICI) and associated detection complexity, thus posing many challenges to practical implementations. This thesis will present solutions for these issues. The thesis commences with the fundamentals by presenting the existing challenges of SEFDM, which are subsequently solved by proposed transceivers. An iterative detection (ID) detector iteratively removes self-created ICI. Following that, a hybrid ID together with fixed sphere decoding (FSD) shows an optimised performance/complexity trade-off. A complexity reduced Block-SEFDM can subdivide the signal detection into several blocks. Finally, a coded Turbo-SEFDM is proved to be an efficient technique that is compatible with the existing mobile standards. The thesis also reports the design and development of wireless and optical practical systems. In the optical domain, given the same spectral efficiency, a low-order modulation scheme is proved to have a better bit error rate (BER) performance when replacing a higher order one. In the wireless domain, an experimental testbed utilizing the LTE-Advanced carrier aggregation (CA) with SEFDM is operated in a realistic radio frequency (RF) environment. Experimental results show that 40% higher data rate can be achieved without extra spectrum occupation. Additionally, a new waveform, termed Nyquist-SEFDM, which compresses bandwidth and suppresses out-of-band power leakage is investigated. A 4th generation (4G) and 5th generation (5G) coexistence experiment is followed to verify its feasibility. Furthermore, a 60 GHz SEFDM testbed is designed and built in a point-to-point indoor fiber wireless experiment showing 67% data rate improvement compared to OFDM. Finally, to meet the requirements of future networks, two simplified SEFDM transceivers are designed together with application scenarios and experimental verifications

Coexistence of FTTC and FTTDp Network Architectures in Different VDSL2 Scenarios

Very high speed Digital Subscriber Line type 2 (VDSL2) systems can achieve significant bit rate values depending on the access network architecture and how far-end crosstalk (FEXT) interference suppression is implemented. The so-called vectoring technology recently became an implementation reality. It was introduced to dynamically suppress ‘self-FEXT’ in a cable of twisted pairs on both downstream (DS) and upstream (US) signals. In the DS direction, crosstalk pre-compensation precedes modulation, and in the US cancellation follows demodulation. However, vectoring allows to effectively eliminate crosstalk if lines belong to the same vectored group. When this condition is not satisfied, in general, even very few uncontrolled interferers can cause significant performance degradation. In this paper, we evaluate by simulation the VDSL2 performance in scenarios of coexistence between Fibre-To-The-Cabinet (FTTC) with vectoring and Fibre-To-The-Distribution point (FTTDp) architectures. We consider two different combinations of VDSL2 band plans assigned to the FTTC and FTTDp networks. We analyse VDSL2 performance in both cases of absence of spectrum management and implementation of the Downstream Power Back-Off (DPBO) technique. We also study the throughput trade-off between the two VDSL2 systems due to DPBO. Results show that, to protect VDSL2 FTTC systems, DPBO must be configured on VDSL2 FTTDp, whereas the investment required to bring the optical fibre to the distribution point could be justified by the improved performance achievable with the FTTDp architecture, even with the VDSL2 band profiles currently used. The presented coexistence analysis can be useful with reference to the G.fast spectrum allocations currently under definition. © 2014 The Authors. Transactions on Emerging Telecommunications Technologies published by John Wiley & Sons, Ltd

Coexistence of FTTC and FTTDp Network Architectures in Different VDSL2 Scenarios

Very high speed Digital Subscriber Line type 2 (VDSL2) systems can achieve significant bit rate values depending on the access network architecture and how far-end crosstalk (FEXT) interference suppression is implemented. The so-called vectoring technology recently became an implementation reality. It was introduced to dynamically suppress ‘self-FEXT’ in a cable of twisted pairs on both downstream (DS) and upstream (US) signals. In the DS direction, crosstalk pre-compensation precedes modulation, and in the US cancellation follows demodulation. However, vectoring allows to effectively eliminate crosstalk if lines belong to the same vectored group. When this condition is not satisfied, in general, even very few uncontrolled interferers can cause significant performance degradation. In this paper, we evaluate by simulation the VDSL2 performance in scenarios of coexistence between Fibre-To-The-Cabinet (FTTC) with vectoring and Fibre-To-The-Distribution point (FTTDp) architectures. We consider two different combinations of VDSL2 band plans assigned to the FTTC and FTTDp networks. We analyse VDSL2 performance in both cases of absence of spectrum management and implementation of the Downstream Power Back-Off (DPBO) technique. We also study the throughput trade-off between the two VDSL2 systems due to DPBO. Results show that, to protect VDSL2 FTTC systems, DPBO must be configured on VDSL2 FTTDp, whereas the investment required to bring the optical fibre to the distribution point could be justified by the improved performance achievable with the FTTDp architecture, even with the VDSL2 band profiles currently used. The presented coexistence analysis can be useful with reference to the G.fast spectrum allocations currently under definition. © 2014 The Authors. Transactions on Emerging Telecommunications Technologies published by John Wiley & Sons, Ltd