Mohammad Faiz Liew Abdullah

Performance of LTE Release 8 and Release 10 in wireless communications

LTE-Advanced (Release 10) is a preliminary mobile communication standard formally submitted as a candidate 4G systems to the ITU-T. It is being standardized by the 3rd Generation Partnership Project (3GPP) as a major enhancement of the 3GPP Long Term Evolution (LTE-Release 8) standard, which proved to be sufficient to satisfy markets demand. The 3GPP group has been working on different aspects to improve LTE performance, where the purpose of the framework provided by LTE-Advanced, includes higher order MIMO, carrier aggregation (carriers with multiple components), and heterogeneous networks (relays, picos). This paper presents a study on evolution LTE toward LTE-Advanced in terms of LTE enabling technologies (Orthogonal Frequency Division Multiplexing (OFDM) and Multiple-Input Multiple-Output (MIMO)). This paper also focuses on LTE-Advanced technologies MIMO enhancements for LTE-Advanced, Coordinated Multi Point transmission (CoMP), repeaters and relays.

A new multi-slot and multi-level coding technique for high capacity communication system

A new multi-slot and multi-level coding technique for high capacity communication system, known as Multi Slot Amplitude Coding (MSAC) is presented. This technique offers better flexibility in terms of defining the symbol based on time slot and signal level in order to generate more unique symbols as a line code with better clock information since all the symbols have zero level (return-to-zero) at the beginning. A set of mathematical equations have been established to relate the parameters of MSAC symbol properties. Theoretical analysis to evaluate the performance of this technique based on the number of slot and the number of signal level against conventional Time Division Multiplexing (TDM), multilevel Mary signaling, and Duty Cycle Division Multiplexing (DCDM) are discussed. The comparison shows that MSAC technique is capable to maximize the number of supportable tributaries with better utilization of the slot and the signal level.

Frequency domain technique for reducing chromatic dispersion

In this paper the chromatic dispersion is reduced using frequency domain technique. Frist an analog signal of specific frequency is generated then signal is converted in digital domain. Digital signal is modulated with QAM scheme. Electrical to optical conversion is performed using intensity modulation. Then this optical signal is propagated in to the fiber channel using the Split step Fourier method which use Nonlinear Schrodinger Equation (NLSE). In this simulated optical channel the 15 Km distance is simulated. At the end of fiber link signal is converted in optical to electrical domain for demodulation. Then Frequency domain techniques FFT is applied to reduce the CD. Pulse shaping filter is used to improve the response signal. During the propagation of signal in the channel signals phase is distorted to improve phase Kaiser Window is used. Pulse evaluation model is compared before and after chromatic dispersion reduction that illustrate that CD is reduced due to frequency domain technique.

All Optical Signal Restoration for 10G DPSK System

Ultrafast Kerr nonlinearity, offers various signal processing functions to be used. Several nonlinear transmission impairment such as phase noise, amplitude noise and power spectral efficiency loss become proficient to degrade the performance of optical systems, when intense power is launched in optical fiber. In modern communication system, all optical regeneration is one of the solution to mitigate transmission impairments instead of O-E-O conversion. In this paper, all optical regeneration is demonstrated for 10G DPSK system using 3R regeneration and phase sensitive amplification to mitigate amplitude and nonlinear phase noise form 10G noisy DPSK transmission system. Bit error rate of 10−12 is achieved at power penalty of 5 dBm. In developed system the novelty exist in compensating two noise simultaneously; ASE noise and phase noise using integrated algorithm developed using 3R and PSA. The system is developed and tested using commercial software package optisystem to check the feasibility of the system design in real time implementation. The developed all optical regeneration system is very demanding for long distance high-speed communication systems. The result conclude the positive feasibility for real time implementation of designed system.

GTL based Internet of Things enable processor specific RAM design on 65nm FPGA

In this work, we Energy Efficient Internet of Things (IoTs) Enable RAM is presented. In order to make it energy efficient, used Gunning Transceiver Logic (GTL) IO Standard and Gunning Transceiver Logic Plus (GTLP). We used the 4 different members of GTL and GTLP IO standards family and searched the most energy efficient among them. We observed that when we use 3.6 GHz operating frequency, there is 90.2% reduction in I/O power when we used GTL instead of GTLP_DCI. We have inserted a 128-bit IP address in RAM to make internet of things enable RAM. Finally, we operated our IOTs Enable RAM with different operating frequency of I3, I5, I7, Moto-E and Moto-X.

Energy-efficient Pseudo Noise generator based optical transmitter for Ethernet(IEEE 802.3az)

In this paper Pseudo Noise generator based optical transmitter is designed to increase the range of Ethernet based networks. Structural changes are proposed in PN generator based optical transmitter for energy efficient Ethernet (IEEE802.3az) to be integrate with different IEEE802.3 protocols (IEEE fiber optic standard). Energy efficient Ethernet design is realized by choosing the most energy efficient IO standards between LVCMOS12 and HSTL_II. Compatibility of this PN generator based optical transmitter is tested for different IEEE802.3 fiber optic standards. The PN generator has operating frequency for 1000BASE-T i.e. IEEE802.3ab, 10GBASE-CX4 i.e. IEEE 802.3ak, 100BASE-T1 i.e. IEEE 802.3bw, 1GBASE-PR i.e. IEEE802.3av is 1000GHz, 10GHz, 100GHz and 1GHz respectively. The LVCMOS12 IO standard will be use in final design to make PN generator more energy efficient, because the power saving for LVCMOS12 is 77.1% more than HSTL_II. There is 96.7% reduction in clock power and 99% reduction in signal power is observed for LVCMOS12 design when using 1GBASE-PR Ethernet configuration for Energy efficient PN generator based optical transmitter. Finally this system will be integrated with other optical components to make optical communication system green. Xilinx ISE14.7 design tool is used to perform the experiment.

Power optimization of Pseudo Noise based optical transmitter using LVCMOS IO standard

In electronic devices when operating frequency is exceeded from its resonant frequency the power of the device increases drastically. Due to this, device reaches in dead zone and will not function anymore. In this work, power optimization is performed for Pseudo Noise sequence based optical transmitter. The PN generator for optical transmitter is designed using linear shift registered generator method. Furthermore, energy efficient design for the PN generator is also proposed using low voltage complementary metal oxide semiconductor (LVCMOS) IO standard available on FPGA virtex-6 board. The PN generator is operated at different frequencies such as 100 MHz, 1 GHz, 10 GHz and 100 GHz and at different LVCMOS IO standard such as LVCMOS 12, 18, 15 and 25. The power reduction is achieved for frequencies using standards available on FPGA. Finally, power optimization is recorded for target device at 100 MHz 97.7%, for 1 GHz 98%, for 10 GHz 95% and for 100 GHz 95% using LVCMOS 12 in comparison with LVCMOS 25. This energy efficient PN generator can be integrated with other optical components to develop green optical communication system. Experiment is performed via Xilinx ISE14.7 design tool and FPGA vertex-6 board.

DSP techniques for reducing chromatic dispersion in optical communication systems

In this paper the chromatic dispersion is reduced for enhancement in the performance of optical communication system. For this an analog test signal is generated and converted into digital domain and modulated with 16 QAM by gray code mapping. Through Split Step Fourier technique the signal is propagated in the optical fiber link for 15 km of simulated distance. At the end of this distance the chromatic dispersion is observed and to reduce Chromatic Dispersion (CD) signal is converted in electrical form at end of optical fiber link. Digital Signal Processing techniques are applied on dispersed signal to reduce the CD. Analysis is based on Bit Error Rate that are compared before and after the induction of chromatic dispersion. In this research CD is reduced electronically so it will save the requirement of optical amplifiers.

Multi Slot Amplitude Coding Performance improvement with level spacing optimization

We reported an optimization method to improve Multi Slot Amplitude Coding (MSAC) optical fiber system performance. Simulation result clearly shows that optimum back to back BER performance is achieved when signal level spacing for upper level is higher than that of the lower level in order to compensate the signal dependent noise. In addition, we compare optimized system performance in terms of optical received power (ORP), optical signal to noise ratio (OSNR) and chromatic dispersion (CD) tolerance with conventional MSAC method. Improvement of 4.5 dB in ORP and OSNR are observed.

Probability of symbol error of Multi Slot Amplitude Coding (MSAC) technique in optical communication system

This paper reports a novel method on the probability of symbol error estimation for high speed Multi Slot Amplitude Coding (MSAC) technique in optically amplified communication system. The system setup is based on simple intensity modulation and direct detection scheme which is cost effective. In this proposed method, possibility of symbol error is estimated based on individual probability density function of particular signal level and slot of MSAC symbol. This proposed method is validated by the symbol-to-symbol error technique.