MIMO-enabled integrated MGDM–WDM distributed antenna system architecture based on plastic optical fibers for millimeter-wave communication

Design of a low-cost fiber–wireless communication architecture is desirable by network operators. Therefore, we demonstrate the transmission of \(2 \times 2\) MIMO spatial streams, each having 2 Gbps DPSK signal to two different radio access units (RAUs) in a distributed antenna system architecture. The proposed architecture employs mode group division multiplexing in combination with wavelength division multiplexing to transport RF DPSK signals centered at 10 GHz. The RF signals are used to modulate optical carriers that are centered at 1300 nm and transmitted toward the RAUs over perfluorinated graded-index plastic optical fiber. Heterodyne detection is performed at the RAUs to transmit mm-wave signals at 60 GHz to the end users. Furthermore, wireline access is also achieved at each RAU to support simplex services. A cost-efficient multiple wavelength source is generated from a single laser by employing a dual-drive Mach–Zehnder modulator. An increase in multiplexing gain is achieved using the two LP modes, LP01 and LP11, of each generated wavelength. The proposed architecture gives acceptable BER results for practical implementation.     

Fiber nonlinearity compensation of WDM-PDM 16-QAM signaling using multiple optical phase conjugations over a distributed Raman-amplified link

In this paper, multiple optical phase conjugation (OPC) devices were used along the optical link to improve the performance of an \(8\times 256\) Gbps polarization-division multiplexing 16-state quadrature amplitude modulation signaling, producing total bit rate of 2.048 Tbps. A 50-GHz spaced, eight-channel wavelength division multiplexing (WDM) communication system was considered using 912 km dispersion-unmanaged standard single-mode fiber link with backward distributed Raman pumps. The performance of a dual-pump highly nonlinear fiber-based OPC was investigated analytically using a set of eight nonlinear Schrödinger equations taking into account the effect of polarization. Simulation results were compared with the case of mid-span optical phase conjugation (MS-OPC) compensation scheme showing better performance in terms of achievable Q-factor, optimal signal launched power, and the total length of the transmission link. In 256 Gbps, single-channel scenario, a Q-factor improvement of 1.35 dB was achieved and the nonlinear threshold was increased by \(\sim \) 4 dB compared to the case of MS-OPC. Moreover, using multiple OPC led to increase the length of the transmission link by 30.7% compared with the case of MS-OPC. In 2.048 Tbps WDM system, a maximum Q-factor of 9.27 dB over the same link was obtained showing an improvement of 0.62 dB over the MS-OPC case. The simulation results were compared with published analogous experimental data showing very good agreement.     

Aggregation defragmentation algorithm based on channel density and minimum gap in elastic optical networks

Free-space optics (FSO) is a data relaying technology, which requires a direct line of sight between the transmitter and the receiver units for reliable transmission. FSO communication links have many merits such as high modulation bandwidth, high data transmission rates, low cost, and easy installation process. The performance of FSO link is affected by certain external parameters such as absorption, scintillation, and atmospheric attenuation due to different weather conditions. This paper reports the designing and simulative comparison of two wavelength division multiplexing-based FSO links under rain and snow weather conditions. The proposed system reports successful transmission of \(32\times 10\) Gbps of data along a link distance of 16.5 and 1.07 km under rain and snow weather conditions, respectively, with acceptable performance levels (\(Q\sim \) 6 dB and \(\hbox {BER} \le 10^{-9}\)).     

Study on the similarity of photonic crystal ring resonator cavity modes and whispering-gallery-like modes in order to design more efficient optical power dividers

In this study, we discuss the wave pattern characteristics of confined cavity modes inside photonic crystal ring resonators (PCRRs). Despite different physical origins, these cavity modes are analogous to the whispering-gallery (WG-like) modes. Because of the absence of perfectly circular symmetry in our PC cavity, the WG-like modes are not degenerate, but they form a close doublet in which the field pattern of each of these doublets repeats itself by \(180^{\circ }/m\) where “m” is the azimuthal index number of WG-like modes. The cavity modes are named according to their symmetric field pattern, and WG-like ones are named by their azimuthal mode numbers “m.” Based on the study of these similarities, we propose a \(1\times 2\) and a \(1\times 4\) T-junction- like power dividers. Through study of the similar properties of these cavity modes with WG-like modes, we have enhanced the output power of both dividers to 49.6 and 24.5 %, respectively. The permittivity of the hexagonal photonic crystal rod is \(\varepsilon _{h}= 12.04\) surrounded by air as the background medium. For our PCRR, the dominant resonating mode is the cavity mode with hexapole field pattern or equivalently WG-like mode with azimuthal mode number of \(m\,=\,6\). The normalized frequencies for this mode and its doublet are \(a/\lambda = 0.348066\) and 0.348301, respectively. The photonic band structure, PC waveguide guided mode and electric field patterns of the confined cavity modes inside the PCRR are calculated using the PWE method, and the transmission spectra are calculated by means of 2D-FDTD simulation method.     

An Efficient Frame Aggregation and Block-ACK Scheme for 60 GHz Short-Range Point-to-Point Transmission

The exploitation of the 60 GHz band is a very promising approach to fulfill the rapidly increasing data rate requirement of wireless indoor communication. One important 60 GHz application is the short-range point-to-point data transmission with Ultra-High-Rate (UHR, up to 10 Gbps) (Krone et al. in International Journal of Microwave and Wireless Technologies, 2011, 189–200). The design of such high data rate systems is very challenging. Except for Analog-Front-End (AFE) and physical layer (PHY) designs, the Medium Access Control (MAC) layer design is also crucial for the achievable system throughput. Among the MAC functionalities, the acknowledgment (ACK) mechanism is a very important component affecting the transmission efficiency and reliability. In this paper, a Hybrid Dynamic Frame Aggregation and Block-Acknowledgment (HD-FABA) scheme is proposed, which enables large-scale frame aggregation and can achieve significant ACK overhead reduction compared to the existing schemes. A theoretical model is developed for throughput analysis, which is verified by packet-level simulation. Both theoretical- and simulation results show that the HD-FABA scheme allows a number of MAC parameters to be optimized according to the PHY conditions (e.g. BER), leading to much higher throughput than with the state-of-the-art scheme.     

A flicker-free CMOS LED driver control circuit for visible light communication enabling concurrent data transmission and dimming control

Recent breakthroughs in solid-state lighting technology have opened the door to a variety of applications using light-emitting diodes (LED’s) for not only illumination, but also optical wireless communication. Low-power CMOS technology enables realization of system-on-chip driver circuits integrating multiple functions to control LED device performance, luminance, and data modulation for “intelligent” visible light networking. This paper presents an LED driver circuit architecture, incorporating analog and digital circuit blocks to deliver concurrent dimming control, and data transmission. This is achieved by independent control of output voltage and current using buck converter and current control loops, respectively. This integrated system incorporates the feedback mechanisms to provide uniform light output together with the peak current control, which also prevents flickering. The proposed architecture is flexible enough to take any digital base band modulation format. Designed and implemented in a 180 nm CMOS process, it provides linear 10–90 % dimming control while transmitting data. It also introduces a mechanism which can be applied to the off-the-shelf LED drivers and make them applicable for the visible light communication applications. The power consumption of on-chip circuitry, is negligible compared to the overall power consumption which yields an efficiency of 89 % at 120 mA of load current. The measured bit error rate (BER) varies from 10^?6 at the data rate of 2.5 Mbps to 10^?2 at the data rate of 7 Mbps. All control functions integrated on-chip with the total power consumption of 5 mW.     

A 0.9–5.4 GHz wideband fast settling frequency synthesizer for 5G based consumer services

In this paper, a frequency synthesizer, based on a type-2, third order phase locked loop (PLL), covering the frequency range of 0.9–5.4 GHz using three voltage controlled oscillators, is implemented using a 0.13-\(\upmu \hbox {m}\) CMOS technology. The PLL has three modes of operation—a high bandwidth mode, a low bandwidth mode and a dynamic mode, in which the bandwidth dynamically changes from a low to a high value, during a frequency jump, and reverts back to low value, once the PLL settles. With a proper choice of bandwidth and timing synchronization during a frequency jump, a worst-case settling time of 3-\(\upmu \hbox {s}\) has been obtained, which is one of the lowest in reported literature. The input clock of the PLL is set to 100 MHz, but it can go as low as 25 MHz without having any effect on its settling time. The PLL consumes 24 mW of power and occupies 0.8 mm\(^2\) of active area.This PLL is expected to be specially useful in wide-bandwidth cognitive radios that require large and fast transitions in the frequency of operation.     

Demonstration of using multi-band 16-QAM OFDM modulation with direct-detection in 10 GHz bandwidth for 37.3-Gb/s PON

We propose and experimentally demonstrate a 37.3 Gb/s passive optical network using four-band orthogonal-frequency-division-multiplexing (OFDM) channels within 10 GHz bandwidth. Here, the required sampling rate and resolution of digital-to-analog/analog-to-digital (DA/AD) converter are only 5 GS/s and 8 bits to accomplish the 40 Gb/s OFDM downstream rate. Moreover, to reduce the power fading and fiber chromatic dispersion issues, a $-$ 0.7 chirp parameter Mach-Zehnder modulator is used for the four-band OFDM modulation scheme. Downstream negative power penalty of $-$ 0.37 dB can be obtained at the bit error rate of $3.8\times 10^{-3}$ after 20 km standard single mode fiber transmission without dispersion compensation.     

Modèles de télétrafic pour le réseau à intégration de services du satellite TELECOM 1

The author discusses models of multiservice circuit switched communications systems where, in particular, the amount of transmission capacity (e.g. bit rate) depends on the call type. Two modes of call set up are considered: «on demand» with blocked calls cleared and «reservation» where capacity is previously reserved for planned calls. The latter mode is described generally and, for particular cases, we suggest interpretations leading to birth process and multiservice queue models. The models have been studied for evaluating the performance of the telecom 1business communication network but derived exact and approximate results should be useful in other applications.     

High-speed MDM-Ro-FSO system by incorporating spiral-phased Hermite Gaussian modes

In the wake of growing challenges of dispersing communication services in rural areas, Radio over Free Space (Ro-FSO) is a useful technology that can carry heterogeneous services. This work focuses on transmitting two independent channels, each carrying 2.5 Gbps data and 10 GHz radio signal, by utilizing mode-division multiplexing (MDM) of two spiral-phased Hermite Gaussian modes (HG00 and HG01) free space optical (FSO) link. It also evaluates the performance of the proposed Ro-FSO system under the impact of beam divergence and various atmospheric turbulences such as moderate fog and heavy fog.     

Joint relay assignment and rate–power allocation for multiple paths in cooperative networks

Multi-path transmission is an efficient way to balance the power consumption from a source to a destination. The previous works have studied rate–power allocation to prolong the network lifetime of multiple paths. As at least one relay node is required to participate into cooperative transmission, its assignment will greatly impact the power consumption of cooperative communication. Thus, this paper addresses the joint resource allocation problem which aims to prolong the lifetime of multi-path cooperative transmission. Given a path set from a source to a destination, we first define the lifetime-optimal relay assignment and rate–power allocation problem (LRRP) for multiple paths with cooperative communications. This paper then presents two heuristic algorithms, called BS-RRP and PS-RRP, to implement efficient resource allocation for multiple paths. The BS-RRP algorithm uses the binary search method to solve the LRRP problem on node-disjoint paths, and reaches the approximate performance 1 ? ?, where ? is an arbitrarily small positive constant. PS-RRP adopts the pattern search method for joint resource allocation on link-disjoint paths, and terminates after finite iterations. The simulation results show that the BS-RRP and PS-RRP algorithms can improve the network lifetimes about 26 and 30 % compared with the resource allocation methods under the non-cooperative communication scheme.     

A 90-nm CMOS 800 MHz 2$$\times$$VDD output buffer with leakage detection and output current self-adjustment

This work presents a 800 MHz 2\(\times\)VDD output buffer with PVTL (Process, Voltage, Temperature, Leakage) detection techniques to reduce slew rate (SR) variation. The threshold voltage (Vth) of MOS transistors varying with PVT is detected such that Output buffer will turn on different current paths correspondingly to decrease or increase the compensation current. Moreover, the slew rate is adjusted by Delay buffer and the leakage current sensor which compensates the dynamic and static currents, respectively. Most important of all, a deterministic sizing optimization method for the output transistors is reported and analyzed. The proposed design realized using a typical 90 nm CMOS process shows that the maximum data rate is 450/800 MHz given supply voltage 1.0/1.8 V with PCB and SMA connectors . The SR variation is reduced over 43% after the compensation of the leakage detection. The core area of the prototype is 0.056 \(\times\) 0.439 mm\(^2\), and the power consumption is 68.9/98.5 (\(\upmu\)W/MHz) at 450/800 MHz, respectively.     

A 5 Gb/s multi-mode transmitter with de-emphasis for PCI Express 2.0/USB 3.0

A versatile transmitter compatible SERDES system was fabricated in 55 nm CMOS technology. The proposed transmitter comprises a low-power and low-area driver with de-emphasis and a 10:1 serializer, meanwhile it supports power management to reduce the unnecessary dissipation and to complete the mode transition among four power modes. Furthermore, the transmitter is compatible with PCI Express 2.0/1.0 and also meets the USB 3.0 standard. The experimental results show this test chip passes PCI Express 2.0/1.0 TX compliance test and USB 3.0 TX compliance test. The chip occupies 0.033 mm² and consumes 33 mA at 5 Gb/s.     

Asynchronous multiple access using flexible bandwidth allocation scheme in SCM-based 32/64QAM-OFDM VLC system

This paper reports a novel asynchronous multiple access using flexible bandwidth allocation scheme in sub-channels-multiplexing-based visible light communication system, adopting quadrature amplitude modulation orthogonal frequency division multiplexing modulation. In this demonstration, an ordinary phosphorescent light-emitting diode with relatively low modulation bandwidth is used. Four sub-channels without any channel spacing are adopted to simultaneously support four users. By using this scheme combined with frequency domain equalization, the data rate of each user can be dynamically reconfigured from 10 to 120 Mb/s, and the overall throughput is above 125 Mb/s at a distance of 120 cm. Furthermore, a data rate of 225 Mb/s by adopting two sub-channels at a distance of 66 cm within the FEC limit of $3.8\times 10^{-3}$ has been also achieved. This scheme has good scalability for supporting more terminals, and high spectrum efficiency due to the dynamic traffic reconfiguration, which shows that it has great potential advantages in future access network.     

Analysis of L-probe Proximity Fed Annular Ring Patch Antenna for Wireless Applications

In the present paper, annular ring patch antenna with L-probe feeding has been analyzed using modal expansion cavity model. The proposed antenna shows wide band and ultra wide band operation which depends on the position of L-probe feeding and position of the shorting pin. For the fundamental \(\hbox {TM}_{11}\) mode, the bandwidth and gain is found to be 38.85 % and 7.8 dBi while for higher order \(\hbox {TM}_{12}\) mode bandwidth is obtained 58.71 % with corresponding gain of 6.1 dBi. The effect of shorting pin on the proposed antenna is also studied and it is found that the radiating structure is more compact in nature and improves the bandwidth upto 47.37 % with 8.0 dBi gain. Further, the proposed antenna has broadside radiation pattern over the entire bandwidth. The theoretical results are compared with IE3D simulated results which are in good agreement.     

Terahertz Frequency- and Mode-Insensitive Broadband Quasi-optical Converter Antenna System

Recently emerged multimode gyrotron, a high-power broadband terahertz radiator, encounters the challenge of efficiently converting a series of operating whispering-gallery modes (WGMs) into free-space Gaussian beams. To this demand, we propose a frequency- and mode-insensitive antenna capable of broadband multimode converting. For a single mode, to achieve broadband operation, special reflector configuration and large-radius launcher guarantee the system high robustness to frequency-induced wave number variation. Furthermore, for a series of operating WGMs, in order to achieve multimode operation, high-order mode indices guarantees familiar field patterns and ray trajectories. In particular, high-purity Gaussian beams are simultaneously achieved in different WGMs of broad continuous bands, including 351–361 GHz for TE_11,2 mode, 375–385 GHz for TE_12,2 mode, and 398–410 GHz for TE_13,2 mode. The results are verified by both the vector diffraction theory and the method of momentum. This kind of mode converter will promote the development of multimode gyrotrons and other antenna-feeder systems for high-power terahertz applications.     

Price-based resource allocation for revenue maximization with cooperative communication

In recent years, cooperative communication becomes a promising technology to improve the spatial diversity for the future mobile network. Under this communication paradigm, both relay assignment and power allocation will greatly impact the network performance. However, since each device may be selfish, a significant challenge is to make the joint resource allocation robust to node selfishness while pursuing the maximum system revenue in the commercial network. This paper mainly studies the price-based joint relay-power allocation problem which aims to maximize the revenue (JRP-RM) while satisfying the bandwidth requirement with cooperative communication. We first analyze the power allocation under the bandwidth and selfishness constraints for different communication modes. According to the analytical results, this paper presents a polynomial-time algorithm, namely MRPA, to solve the JRP-RM problem. We prove its correctness and show that it can achieve an approximation ratio of \(1 - \varepsilon\), where \(\varepsilon\) is an arbitrarily positive constant. Moreover, we study the JRP-RM problem under a special case where the cost and payment are both linear functions of the transmission power. The simulation results show that MRPA can increase the system revenue about 34.2 and 18.9 % compared with the OPRA Yang et al. (2011 IEEE International Conference on Communications (ICC). IEEE, pp 1–6, 2011) and JRPA Xu et al. (Wirel Netw pp 2209–2219, 2010) algorithms while satisfying the selfishness constraint in most situations.     

Photonic crystal $$4{\times }4$$ dynamic hitless routers for integrated photonic NoCs

Contemporary, emerging and exigent breakthroughs in chip multiprocessors (CMPs) lead to atrocious performance and deficit communication between the processor cores in the integrated chips. Photonic network on chip (PNoC) is a worthwhile tactic for the CMP design to attain the excessive performance and efficient communication. Photonic crystal ring resonator-hinged optical router is the delineated pivotal component which has the potential to be exerted on PNoCs to diminish the obstacles in chip multiprocessor with high bandwidth capacity, low transmission delay, low energy dissipation, low crosstalk, etc., Elemental construction of photonic crystal (PC) router of \(4{\times }4\) structures have been formulated by the comprisal of \(1{\times }2\) and \(2{\times }2\) router basic building blocks to review the efficacy of the transmitting behavior between the cores of the processor. Signal transmission for wavelength gamut of 1500–1600 nm is taken for the examination, and the allowed wavelengths toward the end port are tabulated. The signal propagation and analysis are based on plane wave expansion method and finite-difference time-domain method. Crosstalk (CT) and insertion loss (IL) are the crucial determinants of PC ring resonated routers. On the result of the analysis, maximum CT of ? 15.1017 dB at 1567 nm and maximum IL of 1.73 dB at 1520 nm are obtained. The diminutive structures of the router in the size of \(33~\upmu \hbox {m}\times 36~\upmu \hbox {m}\) have been depicted to place the footprints on the integrated photonics of ultra-compact device employment.     

High-performance ultra-compact communication triplexer on silicon-on-insulator photonic crystal structure

Here we reported capable ultra-compact optical triplexer on silicon-on-insulator substrate with resonance cavity for an application of optical communication network. Three cavities are used which can separate three communication wavelengths 1.31, 1.445 and 1.55 \(\upmu \)m. The average output efficiency and quality factor of proposed structure 98% and 2335 obtained, respectively. Proposed triplexer has the very low cross talk of ?25 to ?50 dB. Total foot print of structure 28.4 \(\upmu \mathrm{m}^{2}\) designed that offers strong transverse confinement of light and is promising candidates for photonic integrated circuits such as wavelength division multiplexing, optical communication and compatible with complementary metal–oxide–semiconductor-Si fabrication processes.     

Temperature-Dependent Refractive Index of Quartz at Terahertz Frequencies

Characterisation of materials often requires the use of a substrate to support the sample being investigated. For optical characterisation at terahertz frequencies, quartz is commonly used owing to its high transmission and low absorption at these frequencies. Knowledge of the complex refractive index of quartz is required for analysis of time-domain terahertz spectroscopy and optical pump terahertz probe spectroscopy for samples on a quartz substrate. Here, we present the refractive index and extinction coefficient for α-quartz between 0.5 THz and 5.5 THz (17–183 cm^??1) taken at 10, 40, 80, 120, 160, 200 and 300 K. Quartz shows excellent transmission and is thus an ideal optical substrate over the THz band, apart from the region 3.9 ± 0.1 THz owing to a spectral feature originating from the lowest energy optical phonon modes. We also present the experimentally measured polariton dispersion of α-quartz over this frequency range.