100 Mb/s data transmission on UTP and STP cabling for demandpriority networks

There have been considerable advances towards higher speed (100 Mb/s) workgroup LANs which support the existing UTP and STP structured cabling utilized by 10 BASE-T and token ring LANs. The paper describes the transmission techniques used by an IEEE 802.12 demand priority network with UTP and STP structured cabling. The UTP transmission scheme supports categories 3-5 UTP (i.e. voice-grade and data-grade) using a 5B6B block coded binary signalling scheme on four pairs. This binary signalling scheme is shown to provide better immunity against crosstalk and external (impulse) noise than multilevel signalling schemes. The STP scheme combines the strengths of the 5B6B block code with signalling technology similar to existing SDDI links     

51.84 Mb/s 16-CAP ATM LAN standard

The paper describes the characteristics and performance of the 16-CAP transmission scheme that has been chosen by the Technical Committee of the ATM Forum as the ATM LAN physical layer interface standard at 51.84 Mb/s for category 3 unshielded-twisted-pair (UTP) wiring. The two most attractive features of the 16-CAP transceiver are its capability of operating in the presence of multiple users in a voice-grade UTP cable and the straightforward way in which it can provide scalability to lower speeds. It is also shown in the paper how the carrierless AM/PM (CAP) modulation scheme used for the ATM LAN standard can be utilized to provide substantially higher data rates than 51 Mb/s when there is only one user in a cable. Under this condition, data rates up to 155 Mb/s can be achieved over category 3 wiring and significantly higher rates can be achieved over high-performance category 5 wiring     

A new generation of 90 Mb/s systems: bandwidth efficient, fieldtested 16-QAM

16-QAM (quadrature amplitude modulation) digital satellite broadcast equipment and satellite communications (SATCOM) systems that double the spectral efficiency of currently operational satellite links is described. It is shown that with this field-proven system, data transmission at a rate of 90 Mb/s (two multiplexed DS-3 signals) is feasible in a transmission bandwidth of 30 MHz. Extensive operational satellite tests performed over the T-303 satellite of AT&T demonstrated a BER <10^-10 and no errors for several days. The practical bandwidth efficiency of these SATCOM systems is 3 b/s/Hz, i.e. double the currently used 1.5 b/s/Hz QPSK (quadrature phase-shift keyed) systems. The doubling of the spectral efficiency is attained with advance modem (modulation-demodulation), adaptive equalization robust synchronization, high-power amplifier (HPA) linearization (predistortion), and low redundancy powerful forward-error-correction (FEC) subsystems. The systems may make possible the conversion of currently operational analog FM links into bandwidth efficient digital systems. In one 30 MHz satellite transponder three to four digitized high quality TV signals could be broadcast, or two standard rate DS-3 signals time-division multiplexed with a DS-1 rate signal and additional auxiliary data streams     

A 100-MHz, 50-Ω, -45-dB distortion, 3.3-V CMOS line driverfor Ethernet and fast Ethernet networking applications

A fast line driver has been developed for networking applications in a 0.4-μ digital CMOS process. It is intended to drive cables with large, low-distortion sinewaves for 10BASE-T and sharp-edged pulses for 100BASE-T-type data communications. The driver has a fully differential architecture and uses a current-feedback approach to achieve small- as well as large-signal closed-loop bandwidths in excess of 100 MHz. It can drive a 10-MHz, 5-V_pp sinewave across a 50-Ω load from a 3.3-V power supply with a total harmonic distortion of -43 dB. The quiescent power consumption of the driver is 25 mW, while its area is 0.15 mm²     

100 Mb/s optical-repeater experiment employing graded-index fibres

An optical-repeater error-rate experiment is described in which graded-index fibres up to 8 km long are used as a transmission medium. It is shown that 100 Mb/s modulation can be achieved with sufficiently high quality that the received signal can be regenerated for a given bit rate up to the 8 km fibre tested.     

A quaternary partial-response class-IV transceiver for 125 Mbit/sdata transmission over unshielded twisted-pair cables: principles ofoperation and VLSI realization

The paper describes an experimental transceiver for full-duplex transmission at a rate of 125 Mbit/s over unshielded twisted-pair cables of ordinary voice-grade quality, intended for use in a fiber distributed data interface (FDDI) network. Quaternary partial-response class-IV (QPRIV) overall-channel signaling with near-end crosstalk (NEXT) cancellation and maximum-likelihood sequence detection is employed. The spectral shape of the QPRIV signals facilitates equalization and achieving compliance with EMC regulations. Since in an FDDI system each transmitter can be clocked independently, the receiver must cope with phase drift between NEXT signals to be cancelled and signals received from the remote transmitter. With the chosen transceiver architecture, digital-to-analog conversion of transmit signals, analog-to-digital conversion of receive signals, and adaptive NEXT cancellation are performed synchronously with the transmitter clock. The rate change from transmit timing to controlled receive timing is accomplished by an adaptive equalizer in conjunction with an elastic buffer and occasional coefficient shifts. The equalizer is adjusted rapidly enough to allow for a maximal phase drift of ±100 ppm. The implementation of all digital signal-processing functions in a single 0.5 μm CMOS VLSI prototype chip is discussed. The employed standard-cell design resulted in a power consumption of 6 W. Significantly lower power consumption can be achieved by custom design of highly repetitive processing elements     

Coherent Equalization and POLMUX-RZ-DQPSK for Robust 100-GE Transmission

We discuss the use of a coherent digital receiver for the compensation of linear transmission impairments and polarization demultiplexing in a transmission system compatible with a future 100-Gb/s Ethernet standard. We present experimental results on the transmission performance of 111 Gbit/s POLMUX-RZ-DQPSK. For a dense WDM setup with channels carrying 111 Gbit/s with a 50 GHz channel spacing (2.0 bits/s/Hz), we show the feasibility of 2375 km transmission. This is enabled through coherent detection which results in excellent noise performance, and subsequent electronic equalization which provides the high tolerance to polarization mode dispersion and chromatic dispersion (CD). Furthermore, we discuss the impact of sampling and digital signal processing with either 1 or 2 samples/bit. We show that when combined with low-pass electrical filtering, 1 sample/bit signal processing is sufficient to obtain a large tolerance towards CD. The proposed modulation and detection techniques enable 111 Gbit/s transmission that is directly compatible with the existing 10 Gbit/s infrastructure.     

100-Gb/s DQPSK Transmission Experiment Without OTDM for 100G Ethernet Transport

In order to realize a future 100-Gb Ethernet (100 GbE) transport, 100-Gb/s transmission without 100-GHz-class electronics and optical time-division-multiplexing technique was demonstrated. By using a differential quadrature phase-shift-keying (DQPSK) modulation format and commercially available electronics, 2- and 50-km transmissions of 100-Gb/s signal were successfully achieved over a standard single mode fiber. The receiver sensitivity, chromatic dispersion, and differential group delay tolerances of 100-Gb/s DQPSK signal were also evaluated. Through these evaluations, the possibility of DQPSK modulation for future 100-GbE transport is verified     

Simultaneous electrooptical upconversion, remote oscillatorgeneration, and air transmission of multiple optical WDM channels for a60-GHz high-capacity indoor system

The system concept and data transmission experiments for a mobile broad-band communication system at 60 GHz are presented in this paper. Dense wavelength division multiplexing (DWDM) is advantageously applied for simultaneous electrooptical upconversion of all optical channels carrying individual intermediate-frequency signals by means of a single external modulator. Thus, simple, but flexible, millimetric signal generation is obtained. Using this concept, data transmission experiments at 60 GHz have been carried out. Furthermore, the transponder noise performance is analyzed. Results of coded and uncoded 512-carrier orthogonal frequency division multiplex transmission with 50-Mb/s (subcarrier modulation quaternary phase-shift keying), 100 Mb/s (subcarrier modulation 16-quadrature amplitude modulation) as well as single-carrier modulation at 156 Mb/s utilizing three operational DWDM channels are presented. Uplink and downlink transmission has been realized. The significant performance improvement due to the application of coding is demonstrated in some experiments and line-of-sight transmission is compared to nonline-of-sight transmission. Low bit error rates, employing realistic air link conditions, have been obtained in all experiments     

Transmission Performance Comparison of Direction Detection‐Based 100‐Gb/s Modulation Formats for Metro Area Optical Networks

Transmission performances of direct detection‐based 100‐Gb/s modulation formats are investigated and compared for metro area optical networks. The effects of optical signal‐to‐noise ratio sensitivity, chromatic dispersion, cross‐channel nonlinearity, and transmission distance on the performance of differential 8‐ary phase‐shift keying (D8PSK), differential phase‐shift keying plus three‐level amplitude‐shift keying (DPSK+3ASK), and dual‐carrier differential quaternary phase‐shift keying (DC‐DQPSK) are evaluated. The performance of coherent dual‐polarization quadrature phase‐shift keying (DP‐QPSK) with block phase estimation and coherent DP‐QPSK with digital differential detection are also presented for reference. According to our analysis, all three direct detection modulation formats could transmit a 100‐Gb/s signal over several hundred kilometers of a single‐mode fiber link. The results also show that DC‐DQPSK outperforms D8PSK and DPSK+3ASK, and the performance of DC‐DQPSK is comparable to that of coherent DP‐QPSK with digital differential detection. The maximum transmission distance of DC‐DQPSK is over 1,000 km, which is enough distance for metro applications.     

Millimeter-wave generation and digital modulation in an InGaAs-InPheterojunction phototransistor: model and experimental characterizationof dynamics and noise

This paper describes the use of an InGaAs-InP photoheterojunction bipolar transistor (photo-HBT) for millimeter-wave generation and digital modulation. Optical mixing of two coherent signals generates the carrier, and a digital drive signal to the base is used for the modulation. We describe an advanced large signal model of the photo-HBT that takes into account distributed effects at high frequencies and all noise sources, including optical amplifier noise and noise correlations due to the high operation frequency and the nonlinear mixing processes. The model enables one to predict carrier-to-noise ratio dependence on frequency, optical power, and the transistor operating point. Frequency- and time-domain responses of the modulated millimeter- wave carrier and bit error rates are also calculated. Experiments at 10 and 45 GHz with modulation rates ranging between 50 Mb/s and 2.5 Gb/s were performed, and a superb fit to the calculated responses is found     

Competing for throughput in the local loop

The voice-grade telephone channel is the communication medium most widely available throughout the world. Its limitations, a relatively narrow bandwidth and a moderate SNR figure, have challenged telecommunication researchers and engineers over several decades to develop technologies able to pass higher and higher data rates. The sophisticated combination of trellis coding and quadrature amplitude modulation increases the bandwidth utilization close to the Shannon limit of 10 b/s/Hz for the 3.1 kHz bandwidth voice channel. However, the resultant data rate of about 30 kb/s does not even begin to approach the throughput needed by multimedia applications. Fortunately, twisted pair bandwidth reaches up to several megahertz, so multilevel signaling implemented as in the xDSF family of modems enables data rates of several megabits per second to be reached. Standard ADSL modems are able to deliver 8 Mb/s to a subscriber in the best case. VDSL modems can deliver 52 Mb/s, but only up to 300 m, so their mass implementation will only become possible when fiber migrates into an access network closer to the user premises. Both broadband xDSL solutions approach the Shannon limit and the related spectral efficiency as well, so there is not much room left for a transmission improvement     

Multifunctional characteristics of 1.5-/spl mu/m two-section amplifier-modulator-detector SOA

The multifunctional characterization of a two-section amplifier-modulator-detector semiconductor optical amplifier (AMD-SOA) is presented. Detectivity is analyzed in terms of bandwidth and responsivity while modulation properties are characterized by temporal response and extinction ratio. Receiver sensitivities of -26 dBm at 155 Mb/s and -19.5 dBm at 622 Mb/s and error-free signal modulation/transmission with simultaneous 10 dB amplification at 622 Mb/s with a 2/sup 23/-1 PRBS signal are reported. This device could find application as transparent add-drop node in photonic packet-switched optical ring networks.     

The DTX-240D digital circuit multiplication system

This paper describes the DTX-240D digital circuit multiplication system (DCMS) offered by ECI Telecom. It will accept up to 240 × 64 kb/s trunks carrying either 64 kb/s voice, voice band analogue non-speech signals, or digital data for transmission over a 2·048 Mb/s digital link. Over 1000 are currently ‘on-line’ and carrying traffic. The system comprises a pair of terminals, one on each side of the interterminal digital link (bearer). It will normally operate in the network at a concentration ratio of 5:1, in which case 150 × 64 kb/s trunks, carrying voice, voice band data or digital data can be concentrated into one 2·048 Mb/s bearer. The users are able to increase the number of trunks up to 240 per 2·048 Mb/s bearer, when time zone differences cause a spread of busy-hour traffic carried on a single system. Each terminal will normally be located at an international switching centre (ISC) but may also be located at an earth-station. The system uses a DSI (digital speech interpolation) stage providing a 2·5:1 multiplication, followed by an additional 2:1 multiplication by means of ADPCM (adaptive differential pulse code modulation). In addition, the VBR (variable bit rate) technique is used to prevent clipping, due to overload congestion. The system can also be used with 1·544 Mb/s digital bit streams (trunk side or bearer).     

Fiber-optic transmissions of microwave 8-phase-PSK and 16-aryquadrature-amplitude-modulated signals at the 1.3-μm wavelengthregion

Transmissions of a 6-GHz 8-phase phase-shift-keyed (8φ-PSK) signal over a 12.5-km single-mode fiber with a 5-dB power margin and bit-error-rate (BER) of 10^-10 and a 6-GHz 16-ary quadrature-amplitude-modulated (QAM) signal over the same distance with a 2-dB power margin and BER of 10^-12 were demonstrated. The 8φ-PSK digital modem operated at 78Mb/s and the 16-QAM digital modem operated at 90 Mb/s. A high-speed multimode InGaAsP laser diode and a high-speed p-i-n diode were used in both fiber-optic transmission systems. Floor characteristics and power penalties observed in the BER performances of both systems were found to be caused by the intensity noise of the laser diode, particularly the reflection-induced intensity noise     

Converged delivery of WiMAX and wireline services over an extended reach passive optical access network

In this paper we present long-reach fiber access links supporting transmission of Worldwide Interoperability for Microwave Access (WiMAX) compliant signals. We present bi-directional full-duplex transmission of 256-state quadrature amplitude modulation (256-QAM) modulated WiMAX-compliant signals on a 2.4-GHz RF carrier over an 80-km long-reach access link at 100 Mb/s (down) and 64 Mb/s (up). Transmission of 64-QAM and 256-QAM-modulated signals on a 5.8-GHz RF carrier over a 118.8-km access link converged with four baseband differential quadrature phase shift keying (DQPSK) modulated wireline channels, along with ultra-wide band (UWB) and phase shift keying (PSK) radio-over-fiber (RoF) wireless signals over a deployed optical fiber link is also presented.     

70-GHz-Band OFDM Transceivers Based on Self-Heterodyne Scheme for Millimeter-Wave Wireless Personal Area Network

70-GHz-band orthogonal frequency-division multiplexing (OFDM) transceivers were developed by combining self-heterodyne transmission with two-element diversity reception. The transceivers were used to study and demonstrate a millimeter-wave wireless personal network that enables cost-effective broadband data transmissions in a multipath channel environment. A 100-MHz sampling OFDM modulator/demodulator was developed for the baseband part. It has a payload data rate of 100 Mb/s using quadrature phase-shift keying (QPSK) modulation and a coding rate of 3/4 (many other modulations and coding rate are available). The bit error rate was experimentally evaluated when a pair of devices was placed on a wooden table under line-of-sight path conditions. The results showed that the combined use of the self-heterodyne technique and two-element diversity receiver successfully avoids serious signal fading at unpredictable transmission distances. The transceiver with QPSK modulation and coding rate of 1/2 for forward error correction achieves error-free data transmission over a distance of up to 3.4 m. In addition, a successful transmission in 64 quadrature amplitude modulation mode was demonstrated, although the communication range was quite short.     

全数字化HDTV传输系统图像信源编码的研究

本文研究了一种全数字化HDTV传输系统图像信源编码方案。将运动补偿帧间预测,离散余弦变换编码和二维熵编码技术结合起来,通过对码率的自适应调节,实现HDTV图像信号的压缩编玛。在14.38Mb/s和20Mb/s码率,取得了良好的图像质量。应用数字调制技术,如16-QAM,能够实现在一个基带8MHz射频信道中传输全数字化HDTV。     

A 100 Mb/s BiCMOS adaptive pulse-shaping filter

With the growing demand for high-speed transmission of digital data, there is a challenge for utilizing the existing copper plant as the transmission medium, especially for short-hop links. This medium offers a lower cost to a fiber medium, but requires more sophisticated electronics to account for electromagnetic emissions, cross-talk, and cable loss. These include pulse shaping filters, cross-talk cancelers, and equalizers. To maintain system cost at a minimum, analog solutions are preferred. A continuous-time tunable biquad implemented in a 0.8 μm BiCMOS process and configured as an adaptive pulse-shaping filter is described. The biquad is tunable over the range 10-230 MHz with variable Q factors. It is composed of five transconductance-C integrators each dissipating a static power of 10 mW at 5 V. A method for adapting the filter's pole-frequency and Q-factor while servicing 100 Mb/s NRZ data is presented together with experimental results     

Adaptive analog equalization and receiver front-end control formultilevel partial-response transmission over metallic cables

This paper deals with multilevel partial-response class-IV (PRIV) transmission over unshielded twisted-pair (UTP) cables. Specifically, transmission at a rate of 155.52 Mb/s over data-grade UTP cables for local-area networking is considered. As a low-complexity method used to compensate for cable-length dependent signal distortion, adaptive analog equalization with two controlled parameters is proposed: one parameter determines a frequency-independent receiver gain, the other parameter controls the transfer characteristic of a variable analog receive-filter section. For the stepwise design of the transmit and receive filters, a combination of analytic techniques and simulated annealing is employed. First, the variable equalizer section, then the remaining fixed analog receive filter section are developed and finally the analog transmit filter is determined. The paper also describes the adjustment of the equalizer section, and the control of the sampling phase in the receiver front-end. The two equalizer parameters are controlled by an algorithm that operates on the sampled signals and adjusts these parameters to optimum settings independently of the sampling phase. The latter is controlled by a decision-directed phase-locked loop algorithm that becomes effective when equalization has been achieved. The dynamic behaviour and mean-square error in steady-state obtained with these control algorithms are investigated