Line-coding Scheme Research Articles

A Robust Feature-Based Approach for Recognition of Line Coding Schemes

Decoding communication signals in a non-cooperative environment has always been a challenging task. Even after the estimation of various transmission-related parameters, the unknown received signal still cannot be decoded without the correct classification of the incorporated line coding scheme. In this paper, a robust short-sample feature-based approach is presented which recognizes line coding schemes in a sequential manner by an in-depth examination of linked characteristic features. The proposed approach provides an overall correct classification accuracy higher than 90 percent with an input of just 13 bit-waveforms whereas perfect classification accuracy (100 percent) is achieved with just 30 bit-waveforms of the unknown received signal. A detailed comparison considering noiseless as well as noisy channel environment is also carried out vis-à-vis existing approach based on extensive simulation results. Additionally, the paper bridges the gap between theory and simulations to justify the obtained accuracy results for conventional line codes under consideration. The substantial increase in classification accuracy for a smaller number of input bit-waveforms shall aid effective decoding of the unknown received signal even at the initial stages of reception. In general, it can benefit many practical spectrum surveillance applications, where proactiveness is paramount.

RZ Line Coding Scheme With Direct Laser Modulation for Upgrading Optical Transmission Systems

Abstract This study reports the efficient use of a direct laser modulated response measured with the return-to-zero coding scheme in optical transmission systems. The measured direct laser modulated response has a bit rate of 1.2 Gbps for an optical fiber cable of a transmission length of 10 km. The eye diagram analyzer is used to calculate the maximum quality factor and minimum bit error rate of the proposed model. The maximum quality factor is 531.2, and the minimum bit error rate tends to zero for the same optical fiber channel length compared with that of the previous model. The proposed model provides better results than the previous model. The figures of the proposed model are more stable than those of its previous counterpart. Bit error rate approximately tends to zero in the proposed model.

An iPWM Line-Coding-Based Wireline Transceiver With Clock -Domain Encoding for Compensating Up To 27-dB Loss While Operating at 0.5-to-0.9 V and 3-to-16 Gb/s in 65-nm CMOS

This article presents a clock-domain-based integrated pulsewidth modulation (PWM) (iPWM) line-coding scheme to enable equalization while operating at low supply voltages. While conventional equalizers such as feedforward equalizer (FFE), decision feedback equalizer (DFE), and continuous-time linear equalizer (CTLE) are present on the high-bandwidth data path, the proposed iPWM-based line-coding-based approach moved the equalization logic away from the data path and into the subrate clock path. As a result, the proposed clock-domain iPWM line coding can operate at low supply voltages. An energy-efficient implementation of the proposed scheme was demonstrated. Fabricated in a 65-nm CMOS process, the proposed transceiver operates over a data-rate range of 3-16 Gb/s from 0.5 to 0.9 V. Equalization in this transceiver was done using iPWM and a passive CTLE. Operating at 10 Gb/s at 0.65 V, the proposed transceiver is capable of equalizing up to 27 dB of channel loss at energy efficiency of 1.8 pJ/bit.

Blind Classification of Line-Coding Schemes Based on Characteristic Features

In modern defense technology, signal intelligence plays an important role in military operations as an intelligence source. Among its target signals, telemetry and telecommand signals can use line-coding schemes for their advantageous properties in the presentation of binary data of transmission systems. Therefore, in a non-cooperative context, blind classification of the line-coding scheme is the final crucial step in recovering target information from an unknown received signal. In this paper, we examine the characteristic features of line-coding schemes and then propose a simple blind classification algorithm for the schemes. We also analyze correct classification probabilities of the proposed algorithm in a noiseless and noisy environment through computer simulations. The proposed method can discern line-coding schemes, allowing reconstruction of the original information data.

Alternative Line Coding Scheme with Fixed Dimming for Visible Light Communication

An alternative line coding scheme called fixed-dimming on/off keying (FD-OOK) is proposed for visible-light communication (VLC). FD-OOK reduces the flickering caused by a VLC transmitter and can maintain a 50% dimming level. Simple encoder and decoder are proposed which generates codes where the number of bits representing one is same as the number of bits representing zero. By keeping the number of ones and zeros equal the change in the brightness of lighting may be minimized and kept constant at 50%, thereby reducing the flickering in VLC. The performance of FD-OOK is analysed with two parameters: the spectral efficiency and power requirement.

Source Coding and Preemphasis for Double-Edged Pulsewidth Modulation Serial Communication

Double-edged pulsewidth modulation (DPWM) is less sensitive to frequency-dependent losses in electrical chip-to-chip interconnects. However, the DPWM scheme instantaneously transmits information at a different rate than a synchronous source. This paper presents an 8-/9-bit line-coding scheme to compensate for the timing skew between the DPWM and synchronous clock domains while limiting the size of buffering required in the transmitter and receiver. Furthermore, preemphasis is introduced and analyzed as a means to improve the signal integrity of a DPWM signal. A multiphase-based, time interleaving receiver architecture using a sense amplifier is presented for high-speed data recovery. The DPWM transceiver is implemented in a 45-nm CMOS Silicon on insulator and operates at 10 Gbit/s with $10^{-12}$ bit error rate and consumes 96 mW. The power consumption of the 8-/9-bit coding hardware is 1.5 mW at 10 Gbit/s demonstrating low-power overhead.

Design of Symmetric dispersion compensated, long haul, Single and Multichannel Optical Lightwave Systems in Telecommunications: Theory, Background and Simulation Model-A Study

Here we propose a model on Enhanced- Large Effective Area Fiber (E-LEAF) and Dispersion Compensation Module (DCM) with precise designed Dispersion Compensation Fiber (DCF). The Model is implemented in a long haul Single and Multichannel Optical telecommunication systems with E-LEAF as data transmission Fiber (NZ-DSF) of 1700Km (85 Km SMF×20 loops) length. The DCM is proposed in Symmetric Compensation fashion consisting of 20Km (2Km×20spans) length DCF in Pre-Compensation and Post- Compensation totally comprising of 40Km length DCF for complete Compensation of total Optical Link. Thereby, we study the effect of various Line Coding Schemes like NRZ, RZ, CS-RZ, DUOBINARY and MODIFIED DUOBINARY in single and multichannel optical link with our designed DCM and concluded the suitable line coding scheme for our proposed model. This paper focus on the theoretical background, design procedures, technical terms and finally a simulation model is experimented with proposed parameters to realize the foresaid concepts with various modulation formats.

Design of a new time orthogonal multiuser line code

The design of a new multiuser line-coding scheme based on ideas from collaborative coding multiple access (CCMA) is presented. The new scheme yields good throughput in terms of user information bits per time slot (baud). Separate user data streams (or a single data stream demultiplexed into multiple separate streams) are combined in a binary adder channel. Trade-offs among the number of users, number of time slots per user symbol, and number of user information bits per user symbol are developed, and possible codes are tabulated. A maximum rate of 4.4 bits/baud can be achieved by using five time slots, with two symbols/user and 22 users.

Novel linecoding scheme for optical transmissions

A new linecoding scheme is proposed that can improve the receiver sensitivity of an optical transmission system relative to RZ or NRZ. An associated regeneration method which does not need too complex circuitry is described. A system experiment has demonstrated the feasibility.

Biphase linecoding in optical FSK heterodyne transmission experiment, without sensitivity degradation compared to NRZ

A biphase linecoding scheme was used in a 140 Mbit/s optical FSK transmission experiment. Owing to the analogue decoding, only 0.3 dB sensitivity penalty was observed, compared to NRZ. A sensitivity of − 54dBm was achieved.

Time jitter in self-timed regenerative repeaters with correlated transmitted symbols

This paper deals with the calculation of systematic time jitter in a self-timed regenerative repeater, where the timing circuit consists of a square-law device followed by a high-Q resonant circuit tuned to the transmission rate and a down zero-crossing detector. The method presented here can be used for any linecoding scheme and waveshape of finite duration. Some interrelations between the selected line code and waveform are also studied for the given timing recovery circuit. Examples for different waveforms and codes of practical importance are presented.