Simulation of 1 x 2 OTDM router employing symmetric Mach-Zehnder switches

In high-speed all-optical time division multiplexed (OTDM) routers it is desirable to carry out data routing, switching, clock recovery and synchronisation in the optical domain in order to avoid the bottleneck due to optoelectronics conversion. The authors propose an optical switch based on all-optical symmetric Mach–Zehnder (SMZ) switching and investigate its characteristics. The proposed switch is to be used as a building block for a simple 1x2 OTDM router for asynchronous OTDM packet routing, where clock recovery, address recognition and payload routing are all carried out in the optical domain. Simulation and numerical results demonstrate that clock recovery, address recognition and payload routing are possible with small amounts of crosstalk. Also presented are simulation results for bit error rate (BER) performance for the 1x2 router. For a BER of 10e-9 the receiver sensitivity is -26 dB compared with baseline detection without a router of -38 dB. The proposed router displays great potential for use in ultrahigh- speed OTDM networks

Modelling of all-optical symmetric Mach-Zehnder switch with asymmetric coupler

Ultra high-speed optical network is developing rapidly as growing capacity demand in telecommunication system is increasing. In these networks, it is desired to carry out switching, routing and processing in optical domain to avoid bottlenecks of optoelectronic conversions. Optical time-division multiplexing (OTDM) technique is one option to implement all optical networks. It provides a single data stream at a very high rate (>100Gbits/s) using a single wavelength. These networks will be based on optical packet switching. The success of these networks depends on how well switching and routing are being done at this very high speed. An all optical switch based on symmetric Mach-Zehnder (SMZ) with asymmetric coupler (60:40) is proposed. Its characteristics and switching window profiles will be investigated. The results show that symmetric Mach-Zehnder (SMZ) with asymmetric coupler gives a better contrast ratio rather than symmetric Mach-Zehnder (SMZ) with normal 50:50 coupler

Antenna representation in two-port network scattering parameter

This paper proposes a representation of antenna in two-port network s-parameter, by exploiting the analogy between the antenna and a two-port network, to produce a suitable method for evaluating antennas in system and circuit simulation. Complicated steps required by previous methods to determine an antenna-specific equivalent-circuit and its corresponding resistor, inductor, and capacitor values are avoided. Simulations results obtained for the circuit and system software confirms the validity of the proposed scheme

Design of Normal Mode Helical Antenna for Seawater Application

To overcome the substantial propagation loss in the ocean, a low frequency band should be chosen when contemplating radio wave communication. Then, the antenna used at the portable radio equipment should be very small compare to the wavelength. For the miniaturized antenna, the normal mode helical antenna (NMHA) is suitable because of achieving high efficiency. In this paper, design method of NMHA in the seawater condition (r=81, =4) is explained. The frequency bands of 100MHz and 15MHz are selected. The self-resonant structures are determined based on the theoretical equation. Electrical characteristics such as resonant frequency, input impedance, VWSR and antenna efficiency are obtained through simulation by FEKO simulator. Electromagnetic simulation model is formed by taking into account the practical experimental condition. At 100MHz and 15MHz, resonances are ensured for antenna diameter lengths of 6.83 cm and 12.2 cm respectively. Input resistance of 27.15 and 94.14, antenna efficiencies of -14.88dB and -26.27dB are achieved at 100MHz and 15MHz respectively

Design LTE Microstrip Antenna Rectangular Patch with Beetle-Shaped Slot

In this paper, the microstrip antenna rectangular patch with beetle shaped slot is presented. The characterization results of the proposed antenna obtained by changing the dimensions of the ground plane. CST software is used to design and analyze this proposed antenna. The simulated results of proposed antenna show that the antenna works at the frequency of 2.1 GHz while the return loss of -32.18 dB with the bandwidth reaches 155.19 MHz and the gain of 3.895 dBi

Design of Normal Mode Helical Antenna for Seawater Application

To overcome the substantial propagation loss in the ocean, a low frequency band should be chosen when contemplating radio wave communication. Then, the antenna used at the portable radio equipment should be very small compare to the wavelength. For the miniaturized antenna, the normal mode helical antenna (NMHA) is suitable because of achieving high efficiency. In this paper, design method of NMHA in the seawater condition (r=81, =4) is explained. The frequency bands of 100MHz and 15MHz are selected. The self-resonant structures are determined based on the theoretical equation. Electrical characteristics such as resonant frequency, input impedance, VWSR and antenna efficiency are obtained through simulation by FEKO simulator. Electromagnetic simulation model is formed by taking into account the practical experimental condition. At 100MHz and 15MHz, resonances are ensured for antenna diameter lengths of 6.83 cm and 12.2 cm respectively. Input resistance of 27.15 and 94.14, antenna efficiencies of -14.88dB and -26.27dB are achieved at 100MHz and 15MHz respectively

Coverage Range and Cost Comparison of Remote Antenna Unit Designs for Inbuilding Radio over Fiber Technology

Future communication needs to be ubiquitous, broadband, convergent, and seamless. Radio over fiber (RoF) technology is one of the most important enabler in access network for the technologies. Adoption of RoF faces bottleneck in optoelectronics, that they are still expensive, high power consumption, and limited in bandwidth. To solve the problem, transceiver in remote antenna unit (RAU) is developed, i.e. electroabsorption transceiver (EAT) and asymmetric FabryPerot modulator (AFPM). This paper compares their coverage range and cost in providing WCDMA and WLAN services. Needed gain of RF amplifier for supporting picocell is also discussed

Graphical Approach for RF Amplifier Specification in Radio over Fiber System: Maximum Power Issues

Radio-over-fiber (RoF) technologies address wireless communication’s need for high data rate, protocol- transparency, and flexibility. One of challenge in RoF access point design is RF amplifier requirement that match to microwave-photonic link chosen and service range needed. This paper proposes a graphical approach as systematic method to solve the challenge. The method identifies two regions, i.e. (a) scalable region where amplifiers’ output 1-dB compression point (OP1dB) improvement can enhance system’s maximum input and output power, and (b) saturation region where any improvement on amplifiers’ OP1dB cannot improve AP’s maximum input and output power. The methods have been verified by system simulations. The errors at scalable and saturation regions are less than 1 dB and the standard deviation is no more than 0.6 dB. The error values around the breakpoint between scalable and saturation regions are around 1 dB. Therefore, the proposed graphical approach can be used in the specification tradeoff between RoF access point input and output power, amplifier’s gain and OP1dB

Characterizing The SINR in Poisson Network Using Factorial Moment

Usually, cellular networks are modeled by placingeach tier (e.g macro, pico and relay nodes) deterministicallyon a grid. When calculating the metric performances suchas coverage probability, these networks are idealized for notconsidering the interference. Overcoming such limitation byrealistic models is much appreciated. This paper considered two-tier two-hop cellular network, each tier is consisting of two-hoprelay transmission, relay nodes are relaying the message to theusers that are in the cell edge. In addition, the locations of therelays, base stations (BSs), and users nodes are modeled as a pointprocess on the plane to study the two hop downlink performance.Then, we obtain a tractable model for the k-coverage probabilityfor the heterogeneous network consisting of the two-tier network.Stochastic geometry and point process theory have deployed toinvestigate the proposed two-hop scheme. The obtained resultsdemonstrate the effectiveness and analytical tractability to studythe heterogeneous performance