Showing papers by "Simon Rommel published in 2017"

Nonorthogonal Multiple Access and Carrierless Amplitude Phase Modulation for Flexible Multiuser Provisioning in 5G Mobile Networks

Abstract: In this paper, a combined nonorthogonal multiple access (NOMA) and multiband carrierless amplitude phase modulation (multiCAP) scheme is proposed for capacity enhancement of and flexible resource provisioning in 5G mobile networks. The proposed scheme is experimentally evaluated over a W-band millimeter wave radio-over fiber system. The evaluated NOMA-CAP system consists of six 1.25-GHz multiCAP bands and two NOMA levels with quadrature phase-shift keying and can provide an aggregated transmission rate of 30 Gbit/s. The proposed system can dynamically adapt to different user densities and data rate requirements. Bit error rate performance is evaluated in two scenarios: a low user density scenario where the system capacity is evenly split between two users and a high user density scenario where NOMA and multiCAP are combined to serve up to 12 users with an assigned data rate of 2.5 Gbit/s each. The proposed system demonstrates how NOMA-CAP allows flexible resource provisioning and can adapt data rates depending on user density and requirements.

Optically generated single side-band radio-over-fiber transmission of 60Gbit/s over 50m at W-band

Abstract: 60Gbit/s single side-band multi-band cap radio-over-fiber transmission at W-band is demonstrated. A spectral efficiency of 3.8bit/s/Hz and bit error rates below 3.8×10−3 are achieved after 50m wireless transmission.

Few-mode fiber, splice and SDM component characterization by spatially-diverse optical vector network analysis.

Abstract: This paper discusses spatially diverse optical vector network analysis for space division multiplexing (SDM) component and system characterization, which is becoming essential as SDM is widely considered to increase the capacity of optical communication systems. Characterization of a 108-channel photonic lantern spatial multiplexer, coupled to a 36-core 3-mode fiber, is experimentally demonstrated, extracting the full impulse response and complex transfer function matrices as well as insertion loss (IL) and mode-dependent loss (MDL) data. Moreover, the mode-mixing behavior of fiber splices in the few-mode multi-core fiber and their impact on system IL and MDL are analyzed, finding splices to cause significant mode-mixing and to be non-negligible in system capacity analysis.

Performance Evaluation of Wavelet-Coded OFDM on a 4.9 Gb/s W-Band Radio-Over-Fiber Link

Abstract: Future generation mobile communications running on mm-wave frequencies will require great robustness against frequency selective channels. In this paper, we evaluate the transmission performance of 4.9 Gb/s wavelet-coded orthogonal frequency division multiplexing (OFDM) signals on a 10 km fiber plus 58 m wireless radio-over-fiber link using a mm-wave radio frequency carrier. The results show that a 2 × 128 wavelet-coded OFDM system achieves a bit-error rate of 1e-4 with nearly 2.5 dB less signal-to-noise ratio than a convolutional coded OFDM system with equivalent spectral efficiency for 8 GHz-wide signals with 512 subcarriers on a carrier frequency of 86 GHz. Our findings confirm the Tzannes’ theory that wavelet coding enables high diversity gains with a low complexity receiver and, most notably, without compromising the system's spectral efficiency.

Reconfigurable Radio Access Unit for DWDM to W-Band Wireless Conversion

Abstract: In this letter a reconfigurable remote access unit (RAU) is proposed and demonstrated, interfacing dense wavelength division multiplexed (DWDM) optical and W-band wireless links. The RAU is composed of a tunable local oscillator, a narrow optical filter, and a control unit, making it reconfigurable via software. The RAU allows selection of a DWDM channel and tuning of the radio carrier frequency. Real-time transmission results at 2.5 Gbit/s and performance measurements with offline data processing at 4 and 5 Gbit/s are presented. Error free real-time transmission was achieved after 15 km of standard single mode fiber and 50 m of wireless transmission with carriers between 75 and 95 GHz.

Capacity enhancement for hybrid fiber-wireless channels with 46.8Gbit/s wireless multi-CAP transmission over 50m at W-band

Abstract: Transmission of a 46.8 Gbit/s multi-band cap signal is experimentally demonstrated over a 50 m W-band radio-over-fiber link. Bit error rates below 3.8×10−3 are achieved, employing nine cap bands with bit and power loading.

Real-time measurements of an optical reconfigurable radio access unit for 5G wireless access networks

Abstract: A reconfigurable radio access unit able to switch wavelength, RF carrier frequency and optical path is experimentally demonstrated. The system is able to do the switching processes correctly, while achieving BER values below FEC limit.

Non-Orthogonal Multiple Access and Carrierless Amplitude Phase Modulation for 5G Mobile Networks

Abstract: A combined NOMA and multiCAP scheme is proposed for capacity enhancement of 5G mobile networks and experimentally tested over a W-band millimeter-wave radio-over-fiber system. The evaluated NOMA-CAP system provides an aggregated transmission rate of 30Gbps.

Numerical analysis of misalignment effects in few-mode multi-core fiber systems

Abstract: Few-mode multi-core fiber systems tend to be more prone to core misalignments at splice points. By using the true vector modes of few-mode waveguides we analyze how waveguide properties affect the shape of coupling and mode-dependent loss distributions due to alignment errors between waveguides.

Characterization of a fiber-coupled 36-core 3-mode photonic lantern spatial multiplexer

Abstract: A fiber-coupled 108-port photonic lantern spatial-MUX is characterized with a spatially-diverse optical vector network analyzer. Insertion loss, mode-dependent losses, and time response are measured, showing significant mode mixing at a fiber splice.

Short range inter-datacenter transmission with carrier delivery and remote modulation for 112 Gb/s PM-QPSK signals

Abstract: The increasing demand for bandwidth in datacenter interconnect links is currently driving a transition towards four level pulse-amplitude modulation (PAM-4) as the de facto modulation format. Nevertheless, other schemes with even higher spectral efficiency will be required in the future given the challenges of increasing baud rate or number of channels. As enabling technology, we propose and demonstrate a coherent link concept inspired from passive optical networks (PON) where carrier delivery and remote modulation are used to achieve single wavelength transmission of polarization multiplexing quadrature phase shift keying (PM-QPSK) at 112 Gb/s in channels of 5 and 10 km single mode fiber (SMF). By using a single laser for modulation and local oscillator the required complexity of digital signal processing is reduced in comparison to traditional digital coherent links.

Impulse Response of a 36-Core Few-Mode Photonic Lantern Hybrid Spatial-Multiplexer

Abstract: Space division multiplexing (SDM) using fibers with multiple cores and/or supporting multiple modes has become an essential technology to support Pbit/s transmissions in a single fiber [1,2]. Despite significant mode-mixing in few-mode fibers (FMF), the original signals can be recovered through multiple-input multiple-output (MIMO) equalization, provided mode-dependent loss (MDL) is small [3]. Furthermore, mode scrambling at the transmitter improves tolerance to MDL and maximizes system capacity if all supported modes are used to transmit information [3]. Thus, the MDL and mode mixing properties of spatial multiplexers (SMUXs) are important. In this work, we characterize the impulse response of a 36-core three-mode photonic lantern SMUX, similar to [4], with no mode selectivity, coupled to 2.9m 36core three-mode fiber including a splice, using a spatially diverse optical vector network analyzer (SDMOVNA). Each mode group was identified and significant mode-mixing was found at the splice. The SDM-OVNA setup is a swept-wavelength interferometer as shown in Fig. 1(a), using time multiplexing with fiber delays for separation of device responses from different paths and thus allowing full characterization of one photonic lantern in a single sweep [5]. The measurement of the 36 photonic lanterns yields a 6×6 time domain response for each core, as shown in Fig. 1(b). Reduced 3×3 matrices as shown in Fig. 1(c) and (d) are obtained when summing over the four possible polarization paths between an input-output pair. Comparing these across the 36 cores of the fiber, two groups with different behavior are identified: i) three peaks are visible within the time response matrix entries as in Fig. 1(c), ii) two additional peaks located between the extreme and central peaks are visible as in Fig. 1(d). The groups of cores are found to be in opposite halves of the fiber, as highlighted in Fig. 1(e), showing a camera image of the cleaved fiber facet. Analysis of their relative delays and comparison with the known fiber differential mode delay [2] allows identification of mode groups and mode-mixing paths, showing significant mode mixing to take place at the multicore few-mode fiber splice. Furthermore, insertion loss and MDL of the system are further analyzed. References [1] W. Klaus et al., “Advanced space division multiplexing technologies for optical networks,” J. Opt. Commun. Netw., 9(4), C1–C11 (2017). [2] J. Sakaguchi et al., “Large spatial channel (36-core×3 mode) heterogeneous few-mode multicore fiber,” J. Lightw. Technol., 34(1), 93– 103 (2016). [3] P. J. Winzer and G. J. Foschini, “MIMO capacities and outage probabilities in spatially multiplexed optical transport systems,” Opt. Express, 19(17), 16680–16696 (2011). [4] P. Mitchell et al., “57 Channel (19x3) Spatial Multiplexer Fabricated using Direct Laser Inscription,” Proc. OFC 2014, M3K.5 (2014). [5] N. K. Fontaine et al., “Characterization of space-division multiplexing systems using a swept-wavelength interferometer,” Proc. OFC 2013, OW1K.2 (2013). Figure 1. (a) Spatially-Diverse Optical Vector Network Analyzer Setup; (b)-(d) measured impulse responses: full 6×6 response of core 4, polarization combined 3×3 responses of cores 8 and 30; (e) camera image of cleaved fiber facet with core identifications and regions of different behavior highlighted.

Real-time 2.5 Gbit/s ultra-wideband transmission using a Schottky diode-based envelope detector

Abstract: detector DTU Orbit (05/10/2019) Real-time 2.5 Gbit/s ultra-wideband transmission using a Schottky diode-based envelope detector An experimental demonstration of 2.5 Gbit/s real-time ultra-wideband transmission is presented, using a Schottky diodebased envelope detector fabricated ad-hoc using microstrip technology on a Rogers6002 substrate and surface-mount components. Real-time transmission with a BER below FEC threshold is achieved for 20 cm of wireless transmission at 2.5 Gbit/s and 50 cm at 1.25 Gbit/s.

Analysis of Few-Mode Multi-Core Fiber Splice Behavior Using an Optical Vector Network Analyzer

Abstract: The behavior of splices in a 3-mode 36-core fiber is analyzed using optical vector network analysis. Time-domain response analysis confirms splices may cause significant mode-mixing, while frequency-domain analysis shows splices may affect system level mode-dependent loss both positively and negatively.

Performance Enhancement of Multi-Core Fiber Transmission using Real-Time FPGA Based Pre-Emphasis

Abstract: We experimentally demonstrate pre-emphasis based performance for a 2 km long 7-core multicore fiber link. Simultaneous transmission below the FEC threshold is achievable for all cores by using signal equalization in a FPGA.