Novel cost-effective PON-to-mm-wave RoF photonic bridge for multigigabit access networks

A novel low-cost photonic PON-to-RoF bridge is presented, allowing simultaneous wireline and wireless multi-Gbps data transmission with minor impact on deployed PON networks. Simulation results show that the proposed scheme does not require narrow-linewidth lasers when envelope detector mobile terminals are used, since the transmission performance is not limited by the phase noise but by the RIN and the frequency difference between the two beating lasers. © 2013 IEEE.

Numerical modelling of multimode fibre-optic communication lines

The results of numerical modelling of nonlinear propagation of an optical signal in multimode fibres with a small differential group delay are presented. It is found that the dependence of the error vector magnitude (EVM) on the differential group delay can be reduced by increasing the number of ADC samples per symbol in the numerical implementation of the differential group delay compensation algorithm in the receiver. The possibility of using multimode fibres with a small differential group delay for data transmission in modern digital communication systems is demonstrated. It is shown that with increasing number of modes the strong coupling regime provides a lower EVM level than the weak coupling one.

DC power line communication based on power/signal dual modulation in phase shift full bridge converters

For intelligent DC distributed power systems, data communication plays a vital role in system control and device monitoring. To achieve communication in a cost effective way, power/signal dual modulation (PSDM), a method that integrates data transmission with power conversion, can be utilized. In this paper, an improved PSDM method using phase shift full bridge (PSFB) converter is proposed. This method introduces a phase control based freedom in the conventional PSFB control loop to realize communication using the same power conversion circuit. In this way, decoupled data modulation and power conversion are realized without extra wiring and coupling units, and thus the system structure is simplified. More importantly, the signal intensity can be regulated by the proposed perturbation depth, and so this method can adapt to different operating conditions. Application of the proposed method to a DC distributed power system composed of several PSFB converters is discussed. A 2kW prototype system with an embedded 5kbps communication link has been implemented, and the effectiveness of the method is verified by experimental results.

Performance analysis of an experimental wireless relay sensor network

Communication through relay channels in wireless sensor networks can create diversity and consequently improve the robustness of data transmission for ubiquitous computing and networking applications. In this paper, we investigate the performances of relay channels in terms of diversity gain and throughput via both experimental research and theoretical analysis. Two relaying algorithms, dynamic relaying and fixed relaying, are utilised and tested to find out what the relay channels can contribute to system performances. The tests are based on a wireless relay sensor network comprising a source node, a destination node and a couple of relay nodes, and carried out in an indoor environment with rare movement of objects nearby. The tests confirm, in line with the analytical results, that more relay nodes lead to higher diversity gain in the network. The test results also show that the data throughput between the source node and the destination node is enhanced by the presence of the relay nodes. Energy consumption in association with the relaying strategy is also analysed. Copyright © 2009 John Wiley & Sons, Ltd.

Transmission of data under multipath transmission conditions

The explosive growth in microprocessor technology and the increasing use of computers to store information has increased the demand for data communication channels. Because of this, data communication to mobile vehicles is increasing rapidly. In addition, data communication is seen as a method of relieving the current congestion of mobile radio telephone bands in the U.K. Highly reliable data communication over mobile radio channels is particularly difficult to achieve, primarily due to fading caused by multipath interference. In this thesis a data communication system is described for use over radio channels impaired by multipath interference. The thesis first describes radio communication in general, and multipath interference In particular. The practical aspects of fading channels are stressed because of their importance in the development of the system. The current U.K. land mobile radio scene is then reviewed, with particular emphasis on the use of existing mobile radio equipment for data communication purposes. The development of the data communication system is then described. This system is microprocessor based and uses an advanced form of automatic request repeat (ARQ) operation. It can be configured to use either existing radio-telephone equipment, totally new equipment specifically designed for data communication, or any combination of the two. Due to its adaptability, the system can automatically optimise itself for use over any channel, even if the channel parameters are changing rapidly. Results obtained from a particular implementation of the system, which is described in full, are presented. These show how the operation of the system has to change to accomodate changes in the channel. Comparisons are made between the practical results and the theoretical limits of the system.

1000 Km transmission of 40 Gbit/s single channel RZ data over dispersion managed standard (non-dispersion shifted) fibre

Error-free transmission of a single polarization optical time division multiplexed 40 Gbit/s dispersion managed pulse data stream over 1009 km has been achieved in dispersion-compensated standard (non-dispersion shifted) fibre. This distance is twice the previous record at this data rate.

Quasi-lossless optical links for broad-band transmission and data processing

We present the first experimental implementation of a recently designed quasi-lossless fiber span with strongly reduced signal power excursion. The resulting fiber waveguide medium can be advantageously used both in lightwave communications and in all-optical nonlinear data processing.

Quasi-lossless spans for broadband transmission and data processing

We present the first experimental implementation of a recently designed quasi-lossless fibre span with strongly reduced signal power excursion. The resulting fibre waveguide medium can be advantageously used both in lightwave communications and in all-optical nonlinear data processing.

Quasi-lossless optical links for broad-band transmission and data processing

We present the first experimental implementation of a recently designed quasi-lossless fiber span with strongly reduced signal power excursion. The resulting fiber waveguide medium can be advantageously used both in lightwave communications and in all-optical nonlinear data processing. © 2005 IEEE.

Quasi-lossless spans for broadband transmission and data processing

We present the first experimental implementation of a recently designed quasi-lossless fibre span with strongly reduced signal power excursion. The resulting fibre waveguide medium can be advantageously used both in lightwave communications and in all-optical nonlinear data processing.

Robust H.264/AVC video transmission using data partitioning and unequal loss protection

In this work, we present an adaptive unequal loss protection (ULP) scheme for H264/AVC video transmission over lossy networks. This scheme combines erasure coding, H.264/AVC error resilience techniques and importance measures in video coding. The unequal importance of the video packets is identified in the group of pictures (GOP) and the H.264/AVC data partitioning levels. The presented method can adaptively assign unequal amount of forward error correction (FEC) parity across the video packets according to the network conditions, such as the available network bandwidth, packet loss rate and average packet burst loss length. A near optimal algorithm is developed to deal with the FEC assignment for optimization. The simulation results show that our scheme can effectively utilize network resources such as bandwidth, while improving the quality of the video transmission. In addition, the proposed ULP strategy ensures graceful degradation of the received video quality as the packet loss rate increases. © 2010 IEEE.

10-Gb/s transmission over 100 Mm of standard fiber using 2R regeneration in an optical loop mirror

The transmission of a 10-Gb/s data stream was demonstrated experimentally over a practically unlimited distance in a standard single-mode fiber system using nonlinear optical loop mirrors as simple in-line 2R regenerators. Error-free propagation over 100 000 km has been achieved with terrestrial amplifier spacing. © 2004 IEEE.

Long distance dispersion managed soliton transmission experiments

This thesis presents results of transmission experiments using optical solitons in a dispersion managed optical fibre recirculating loop. The basic concepts of pulse propagation in optical fibre are introduced before optical solitons and their use in optically amplified fibre systems are discussed. The role of dispersion management in such systems is then considered. The design, operation and limitations of the recirculating loop and soliton sources which were used and the experimental techniques are described before the experimental work is presented. The experimental work covers a number of areas all of which used dispersion management of the transmission line. A novel ultra-long distance propagation scheme which achieved low timing jitter by suppression of the amplifier noise and by working close to the zero dispersion wavelength has been discovered. The use of fibre Bragg gratings as wavelength filters to suppress noise and reduce timing jitter has been investigated. The performance of the fibre grating cornpared favourably with that of a bulk device and was in good agreement with theoretical predictions. The upgrade of existing standard fibre systems to higher bit rates is currently an important issue. The possibility of using solitons with dispersion compensation to allow an increase in data rate of existing standard fibre systems to 10Gbit/s over 5000km has been demonstrated. The applicability of this technique to longer distances, higher bit rates or longer amplifier spans is also investigated by optimisation of the dispersion management scheme. The use of fibre Bragg gratings as the dispersion compensating elements in such standard fibre transmission experiments has been examined and the main problem that these devices currently have, high polarisation mode dispersion, is discussed. The likely future direction of optical communications and what part solitons and dispersion management will play in this development is discussed in the thesis conclusions

WDM of solitons in dispersion managed transmission systems

This thesis investigates the physical behaviour of solitons in wavelength division multiplexed (WDM) systems with dispersion management in a wide range of dispersion regimes. Background material is presented to show how solitons propagate in optical fibres, and key problems associated with real systems are outlined. Problems due to collision induced frequency shifts are calculated using numerical simulation, and these results compared with analytical techniques where possible. Different two-step dispersion regimes, as well as the special cases of uniform and exponentially profiled systems, are identified and investigated. In shallow profile, the constituent second-order dispersions in the system are always close to the average soliton value. It is shown that collision-induced frequency shifts in WDM soliton transmission systems are reduced with increasing dispersion management. New resonances in the collision dynamics are illustrated, due to the relative motion induced by the dispersion map. Consideration of third-order dispersion is shown to modify the effects of collision-induced timing jitter and third-order compensation investigated. In all cases pseudo-phase-matched four-wave mixing was found to be insignificant compared to collision induced frequency shift in causing deterioration of data. It is also demonstrated that all these effects are additive with that of Gordon-Haus jitter.

Numerical modelling of dispersion managed soliton transmission

This thesis presents the results of numerical modelling of the propagation of dispersion managed solitons. The theory of optical pulse propagation in single mode optical fibre is introduced specifically looking at the use of optical solitons for fibre communications. The numerical technique used to solve the nonlinear Schrödinger equation is also introduced. The recent developments in the use of dispersion managed solitons are reviewed before the numerical results are presented. The work in this thesis covers two main areas; (i) the use of a saturable absorber to control the propagation of dispersion managed solutions and (ii) the upgrade of the installed standard fibre network to higher data rates through the use of solitons and dispersion management. Saturable absorbe can be used to suppress the build up of noise and dispersive radiation in soliton transmission lines. The use of saturable absorbers in conjunction with dispersion management has been investigated both as a single pulse and for the transmission of a 10Gbit/s data pattern. It is found that this system supports a new regime of stable soliton pulses with significantly increased powers. The upgrade of the installed standard fibre network to higher data rates through the use of fibre amplifiers and dispersion management is of increasing interest. In this thesis the propagation of data at both 10Gbit/s and 40Gbit/s is studied. Propagation over transoceanic distances is shown to be possible for 10Gbit/s transmission and for more than 2000km at 40Gbit/s. The contribution of dispersion managed solitons in the future of optical communications is discussed in the thesis conclusions.