The power consumption of a system is one of the important figures of merit that can be expressed by the power consumption per user versus the average access rate (Watts/Mbps). The energy efficiency of a system can also be measured as the energy consumed per bit of data transferred (Joules per bit). The power consumption of an access network infrastructure is designed on the basis of network segmentation. The energy consumption of each part of the system for a range of access rates is computed using manufacturer’s data on equipment energy consumption for a range of typical types of hardware. To predict the rise in power consumption because the number of users and access rate per user is increasing rapidly, this perspective provides a better platform. For a ROF system, the power efficiency should account for both optoelectronic and electrical components in the CS. With less offering, most of the power consumption of optoelectronic components is required in the amplifier’s pump lasers and transmission lasers of an active ODN, and also in the electronic components at the RNs that perform the control and management functions. Power consumption of the BSs is of special importance, since the large numbers of BSs are needed to cover a service area. Since, BS accounts for up to 70% of the total power consumption in commercial cellular systems, therefore BS design has the most opportunities for saving energy. In ROF, the power consumption model for BS includes the mm-wave frequency to be radiated, the expected cell coverage or transmitting power and the transmission schemes for uplink and downlink. The BS power consumption varies depending on the transmitting power and traffic load, the higher is the traffic or transmitting power, higher power will be consumed by the BS .
Abstract—In this paper, we propose a new approach to generate quadrupling-frequency optical millimeter-wave (mm-wave) signal with carrier suppression by using two parallel Mach-Zehnder modulators (MZMs) in Radio-over-fiber (RoF) system. Among the numerous properties of this approach, the most important is that a filterless optical mm-wave at 60 GHz with an optical sideband suppression ratio (OSSR) as high as 40 dB can be obtained when the extinction ratio of the MZM is 25 dB. Simplicity and cost-effectiveness have made this approach a compelling candidate for future wave-division-multiplexing RoF systems. Theoretical analysis is conducted to suppress the undesired optical sidebands for the high-quality generation of frequency quadrupling mm-wave signal. The simulation results show that a 60 GHz mm-wave is generated from a 15 GHz radio frequency (RF) oscillator with an OSSR as high as 40 dB and an radio frequency spurious suppression ratio (RFSSR) exceeding 35 dB without any optical or electrical filter when the extinction ratio of the MZM is 25 dB. Furthermore, the effect of the non-ideal RF-driven voltage as well as the phase difference of RF-driven signals applied to the two MZMs on OSSR and RFSSR is discussed and analyzed. Finally, we
The demand for broadband services has driven research on millimeter (mm) wave frequency band communications for wireless access network due to its spectrum availability, and compact size of radio frequency devices [6, 7]. However, the mmwave signals suffer from severe loss along the transmission as well as atmospheric attenuation. In other words, upcoming wireless networks will use a combination of air interface methods in different channels and in different cells that can be changed dynamically to meet variations in traffic conditions. One of the solution to overcome these problem is by using low attenuation, electromagnetic interference-free optical fiber. Radio over Fiber (ROF) is integration of optical fiber for radio signal transmission within network infrastructures that is considered to be cost effective, practical and relatively flexible system configuration for long-haul transport of millimeter frequency band wireless signals. Fiber optic local area networks (LANs) will be carrying traffic at data rates of tens of gigabits per second in the near future, whereas data rates of tens of megabits per second are difficult to provide to mobile users [8-10]. In the present study, the model deeply investigated for ROF communication systems within multi mode polymer optical fibers for short transmission applications. Normally the MMF is used in short distance transmission applications within polymer optical fibers links. ROF systems have presented high transmission bit rates per transmitted channels in polymer fibers links.
This architecture, illustrated in figure 3.2, transports an RF mm-wave signal on both the downlink and the uplink. It therefore enables the construction o f the simplest RAU, since no u p /d o w n conversion at the RAU is necessary. A promising technology to achieve this bi directional transmission is the electroabsorption transceiver (EAT) [99,100,101]. An EAT consists o f a multi-quantum well (MQW) III-V semiconductor active waveguide where the absorption edge o f the M QW waveguide changes with the applied reverse bias voltage owing to the quantum — confined Stark effect . This allows light with a wavelength slightly above the absorption edge to be modulated, while light o f a wavelength \ below the absorption edge is completely absorbed. Consequently, a single EA T can simultaneously serve as a photodiode and a modulator by using a dual wavelength channel allocation for the bi-directional link. It is also possible to operate the up-channel in a loop-back configuration by locating the upstream optical source within the central office. Since this system is based on the external modulation o f the optical carriers, dispersion compensation is required if the cyclic variation o f the generated RF power with fibre distance is to be avoided .
night and higher during the day. During the day it is possible to communicate via both the E and F layers using different frequencies. The highest frequency supported by the E layer is the EMUF, while that supported by the F layer is the FMUF. The F region MUF in particular varies greatly throughout the day, seasonally and with the solar cycle. D region absorption of HF radio waves increases rapidly with decreasing frequency. The angle at which the radio waves enter the atmosphere (angle of incidence) defines the path that will be covered by the waves on their way to Earth. The angle of incidence should be small enough for the waves to be reflected back to Earth and large enough so that the waves will not penetrate the ionosphere layer. Smaller critical angles should be used for smaller frequencies and larger critical angles should be used for larger frequencies so that they will not penetrate through the ionosphere layer and be lost in space. The range of usable frequencies will vary:
Moreover, it is vital to study radiowave propagation peculiarities at mm-wave frequencies in indoor and outdoor environments to be able to deploy wireless networks effectively. The propagation part of the thesis focuses on several aspects. First, we investigate how the estimation of optimum antenna conﬁgurations in indoor environment can be done using realistic propagation models at 60 GHz. Ray tracing simulations are performed and realistic human blockage models are considered. Second, we present the results from a measurement campaign where reﬂection and scattering properties of two different built surfaces are studied in the millimeter-wave E-band (71-76 and 81-86 GHz). Next, we present a geometry based channel model for a street canyon scenario, using angular-domain measurement results to calculate realistic power angular spectra in the azimuth and elevation planes. Then, we evaluate propagation effects on the radio channel on the rooftop of the buildings by measurements and simulations. We have used unmanned aerial vehicles and photogrammetry technique to create a highly accurate 3D model of the environment. Based on a comparison of the measured and simulated power delay proﬁles, we show that the highly accurate 3D models are beneﬁcial in radiowave propagation planning at mm-wave frequencies instead of using simple geometrical models.
POWER for switching the radio on and off LOCK for blocking all button functions METER for selecting the short-wave band RADIO/BUZZ for setting the alarm to radio or buzzer SLEEP for switching on the sleep function BATTERIES Inside the batteries compartment: SW FREQ. selector
With continuing advances in CMOS technology, feature sizes of modern Silicon chip-sets have gone down drastically over the past decade. In addition to desktops and laptop proces- sors, a vast majority of these chips are also being deployed in mobile communication devices like smart-phones and tablets, where multiple radio-frequency integrated circuits (RFICs) must be integrated into one device to cater to a wide variety of applications such as Wi-Fi, Bluetooth, NFC, wireless charging, etc. While a small feature size enables higher integra- tion levels leading to billions of transistors co-existing on a single chip, it also makes these Silicon ICs more susceptible to variations. A part of these variations can be attributed to the manufacturing process itself, particularly due to the stringent dimensional tolerances associated with the lithographic steps in modern processes. Additionally, RF or millimeter- wave communication chip-sets are subject to another type of variation caused by dynamic changes in the operating environment. Another bottleneck in the development of high per- formance RF/mm-wave Silicon ICs is the lack of accurate analog/high-frequency models in nanometer CMOS processes. This can be primarily attributed to the fact that most cutting edge processes are geared towards digital system implementation and as such there is little model-to-hardware correlation at RF frequencies.
A metal conductor over the ground plane and dielectric material filled between them acts as microstrip transmission line. When a signal is applied, voltages and currents travel in the form of electric and magnetic fields at the speed of light. If one solves the electromagnetic equations to find the field distributions in the vicinity of a microstrip, one finds very nearly a completely TEM (transverse electromagnetic) wave pattern. This means that there are only a few regions in which there is a component of electric or magnetic field in the direction of (as opposed to perpendicular to the direction of) wave propagation. This field pattern is commonly referred to as a quasi TEM pattern -.
Kambiz Hadipour was born in Tehran, Iran, in 1984. He received the bachelor degree in Electrical Engineering from Zanjan University, Zanjan, Iran in 2006. In 2010, he received the master degree with honor from Tarbiat Modares University, Tehran, Iran. He is currently working towards the Ph.D degree in Microelectronics at University of Pavia. His major research interests include RF and mm-wave IC design on advance CMOS technologies. From 2007 he has been a student member of IEEE and IEEE Solid State Circuits Society.
(including walls and floors) appears rougher as the fre- quency increases; on the other hand, smaller penetra- tion depths are experienced at higher frequencies. The former aspect might contribute to enhance DS due to surface irregularities, whereas the latter may lead to a reduction of the scattering effects related to volume unhomogeneities. Moreover, even small objects com- monly not present in the input database may behave as specular reflector at mm-waves due to the smaller wave- length and therefore could contribute also to what we would define SMC . Whether an increase of diffuse scattering must be expected at mm-wave or rather a re- duction is an issue still under debate . Hence, multi- path interactions at mm-wave could be not simply modeled based on the studies carried out at much lower frequencies. An “item level” characterization of radio- wave propagation at mm-wave including scattering from smaller objects is therefore addressed in this work. The scattering properties of several, different objects have been investigated at 70 GHz by means of measure- ments performed in an anechoic chamber. The mea- sured data have been also exploited to tune some parameters included in a 3D RT model.
With the rapid development of electronic counter, radar, space research, etc., the millimeter (mm) and sub-mmwave frequencies have come to be a hot research band for channel capacity. Traveling wave tubes (TWT), which is a kind of important microwave source both in military and civil areas for possessing advantages of wide bandwidth and high power, cannot be replaced in the mmwave band [1, 2]. Slow-wave structure (SWS) is a key part in TWT because it directly determines the TWT’s properties. But the physical dimension of SWS for mmwave devices becomes too small to manufacture easily, which makes it a current research topic to ﬁnd a new type of SWS for mmwave TWT. The rectangular grating is an ideal candidate SWS for mmwave TWT for the advantages of the scalability to smaller dimension, interaction with sheet beam, which may reach the peak powers as high as several hundreds of kilowatts in high frequency band (100 to 300 GHz). The open rectangular grating is a deformation of rectangular grating by disposing the metal short circuit side plates, which is open in the transverse direction. This kind of SWS has attracted much interest due to its all-metal structure features: super thermal capacity, low loss, high precision of manufacturing and assembling, high power capacity, compact dimension, which make it to be applied as interaction circuits for mmwave frequency especially. It is proved in [3–6] that the larger the groove depth is, the slower the phase velocity of the electromagnetic wave is. In other words, the groove depth should be increased to obtain slow electromagnetic wave which should be synchronous with the electron beam inside TWT, but this may cause remarkable skin dissipation, which will decrease the output power of the open rectangular grating TWT. To improve the high frequency characteristics of open rectangular grating SWS in the case of
In the late 1800s and early 1900s, wireless transmission of information started its journey. During this period, inventors such as David E. Hughes, Heinrich Hertz, Nikola Tesla, Guglielmo Marconi, Reginald Fessenden, and Edwin H. Armstrong had to work with long wavelengths due to the lack of high frequency amplifiers , . At frequencies smaller than 10 GHz, the size of an efficient antenna is much larger than the size of the active devices used. The practical issues involved in implementing such large antennas limited the number of effective solutions for designing wireless transceivers. Among these solutions, we can mention the invention of the regenerative, heterodyne, and homodyne receivers  , . With his invention of super-heterodyne receiver in 1918, Armstrong introduced the idea of modulating the signal at low frequencies, or baseband, and up-converting it to the RF frequency. Since that time, there have been many breakthroughs in related technologies including the invention of the transistor itself in 1947. However, there have been few fundamental changes in transceiver architectures despite the availability of revolutionary supporting technologies; most of today’s high- performance systems still use ideas based on the heterodyne or homodyne architectures. Today’s silicon technologies provide transistors with unity-current-gain frequencies (f T )
occurs. As an example, curve 2 in Figure 13 shows the eﬀect of random variation of thickness of m and q wafers across the area of each wafer with standard deviation δm = δq = 0 . 2 µ m in case of no absorption (the value of 0 . 3 µ m would further reduce the peak by more than 1 dB). A similar eﬀect arises when a tilt is introduced in an ideal structure so that one of the air spaces t linearly increases from t = 0 . 911 mm to t = 0 . 921 mm across the wafer diameter (the Gaussian beam of the waist radius w A = 24 mm is used in this estimate). Wafer non-ﬂatness also contributes to this eﬀect.
The holmium:YAG (Ho:YAG) laser is effectively used for transurethral ureterolithotripsy. The laser is applied through an optical fiber in a ureter. A bubble is formed by a laser irradiated from the fi- ber tip and a calculus is crushed by the impact of the bubble collapse. In this study, we observed the characteristic behavior of a bubble induced by a Ho:YAG laser near a wall surface, using a high-speed video camera. Furthermore, we measured the forces of a bubble collapse using an im- pulsive force sensor. As a result, we showed characteristic bubble collapse behavior and impulsive force distribution for various fiber placement conditions.
ABSTRACT In this paper, we develop novel precoder and combiner schemes for multi-user hybrid digital- to-analog (D-A) beamforming for uplink massive multiple-input multiple-output millimeter wave (mm- Wave) systems, where the number of radio frequency chains is much smaller than the number of antennas each transceiver is equipped with. Industry 4 . 0 targets to accelerate the digitalization of manufacturing processes by allocating fixed and mobile robotics which use wireless communication. Such development requires high data throughput for which the utilization of short distance wireless communication such as mm-Wave system is crucially required. Based on our measurements, the probability of mm-Wave propagation waves to be reflected and refracted from metallic surfaces are shown to be significantly high. Consequently, uplink transmissions from different users such as robotics, machines, and sensors can go through paths sharing the same physical scatters, some transmission paths of different users may have overlapped angle of arrivals (AoAs) at the base station. Under such circumstance, the correlation between the channel vectors also increases considerably, which affects the achievable uplink rate severely. Therefore, the intrinsic focus is on substantially maximizing the desired signal while reducing the system interference. The proposed analog precoders and combiners are designed by using the power iteration and the Riemannian optimization method based on Stiefel manifold algorithms, respectively. The proposed digital combiner adapts the minimum mean-square error by judiciously exploiting the effective uplink analog channel gains. Furthermore, the channel estimation is investigated through a newly designed two-step procedure. In each scattering point, there is the strongest power point which is detected and then used to improve the accuracy by employing an angular domain scheme. The impact of this paper will be the boosting of the achievable uplink rate in industrial environments.
ABSTRACT: Fiber optics sensor technology is use to measure different parameters such as strain, pressure, temperature, to detect a large number of toxic substances and other chemical constituents in sea, water and air, detection of various diseases and many more. This report describes the study and design of evanescent wave absorption field sensor and its application of detection of nitrate concentration in water.
ABSTRACT: The approach in this paper is to analyze the propagation features of three distinct bands above 6GHz (i.e. 19, 28 and 38GHz) in an indoor corridor setting. The performance of 3GPP, NYUSIM channel models, Floating Intercept (FI), Frequency Attenuation (FA) path loss models are assessed using propagation features. Most of the available bands are now being used in the microwave band are below 6GHz. For the 5G system, the microwave band above 6GHz and mm-Wavebands can be used as bandwidth needed for all 5G applications. The analysis of LOS scenarios, channel Eigen values and spectral efficiency analyzes the channel model for the propagation of 5G mm-Wave bands.
The unique dynamics of mm-wave communications, i.e., higher achievable data rates with high variability in channel quality, present particular challenges to the design of the physical (PHY) and medium access control (MAC) layers. To this date, the majority of the research has been devoted to investigate propagation issues , , beamforming pro- cedures , and MAC layer design aspects . However, the extreme propagation conditions of mm-wave links also impact the transport layer and especially the congestion control mechanisms. The role of congestion control is to regulate the amount of injected traffic in the network according to its con- gestion state. However, in wireless communications, traditional congestion control protocols like TCP NewReno are unable to differentiate between losses attributed to congestion and those attributed to transmission errors caused by a decay in channel quality. This well known problem is vastly exacerbated in mm- wave networks because of the magnitude of rate variations that sudden transitions from Line of Sight (LoS) to Non-LoS (NLoS) cause. At the transport layer, the sender is not notified about such short-term changes and might not decrease im- mediately the congestion window. Instead, lower layers react immediately by lowering the Modulation and Coding Scheme (MCS) used for subsequent data transmissions to increase robustness against adverse channel conditions. Preliminary works in this area analyzed the system-level implications of mm-wave channels on transport protocols , and have focused on understanding the performance of Multipath-TCP and the impact of link level retransmissions . Additionally, Azzino et al.  proposed a cross-layer optimization of the congestion window, that is set according to the bandwidth- delay product by considering the latency estimated without buffering delays.