A Review on Indoor Optical Wireless Systems
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paper_title: Performance of infrared transmission systems under ambient light interference

paper_content:

Optical transmission systems are mainly impaired by the shot noise induced by ambient light, the transmitted optical power limitations (high path losses), the channel bandwidth limitations owing to multipath dispersion and the interference produced by artificial light sources. Several modulation and encoding schemes have been proposed for this channel and their performance has been studied and presented by several authors while neglecting the effects of the artificial light interference. The work reported extends the previous analysis by taking into account the optical power penalty induced by artificial light interference. An analytical approach is used to estimate this. In practical systems, the effect of the interference is usually mitigated using electrical highpass filters. In the paper the combined effect of interference and highpass filter is evaluated. The presented results show that the interference produced by fluorescent lamps driven by electronic ballasts induce high power penalties in OOK and L-PPM systems, even when electrical highpass filtering is used, for data rates up to 10 Mbit/s. For the interference produced by incandescent lamps and fluorescent lamps driven by conventional ballasts, the power penalty induced in OOK systems can be effectively reduced using highpass filtering, while PPM is very tolerant to that interference even without any highpass filtering. The major conclusion is that artificial light interference have to he considered both in system design and performance evaluation.
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paper_title: High-speed nondirective optical communication for wireless networks

paper_content:

The primary obstacles to high-speed communication, namely, shot noise from ambient light, high-capacitance photodiodes and multipath dispersion, are reviewed, and ways to counter them are demonstrated for a prototypical infrared system. The discussion is limited to the physical-layer issues involved in the design of a single high-speed optical link. The focus is on the downlink (from base station to portable), which is a more challenging problem technically than the uplink for two reasons. First, the complexity of the portable receiver is much more constrained than that of the base station, due to power consumption and cost restrictions. Second, the downlink data rates are likely to be much higher than the uplink rates, because downlink communication will include downloading large executable files and possibly video services, whereas uplink communication will be used for transferring working files and keyboard commands which tend to be much smaller. >
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paper_title: Indoor ambient light noise and its effect on wireless optical links

paper_content:

Knowledge of ambient optical noise is essential for designers of free space optical links, for designing resilient circuits. An experimental characterisation of the most commonly encountered ambient optical radiation is presented. The study includes tungsten filament sources, low and high frequency fluorescent lights, IR headphones, TV remote controls and daylight. Practical means to reduce their influence on the performance of the links are also given. The results are also valuable for setting a standard way of comparing wireless IR links, based on testing their performance under such ambient noise.
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paper_title: Wireless communications in the automated factory environment

paper_content:

The networking issues involved in the use of infrared communications in a factory environment are described. A brief history of the use of infrared and radio for indoor (factory environment) communications is given, and the physical infrared environment is reviewed. Topology and protocol alternatives are compared.<<ETX>>
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paper_title: Wireless in-house data communication via diffuse infrared radiation

paper_content:

A novel wireless broadcast/multi-access channel is described for flexibly interconnecting a cluster of data terminals located within the same room. The transmission medium is diffusively scattered infrared radiation at 950-nm wavelength. Transmission is low-to-medium speed and the range up to 50 m. Theoretical analysis indicates that the time dispersion limits the transmission bandwidth of the system to 260 Mbit ċ m/s, but background noise produced by ambient daylight reduces the transmission speed below 1 Mbit/s. The transmission properties of the diffuse optical channel are analyzed, and experimental digital links for baseband PCM at 125 kbit/s and PSK 64 kbit/s are demonstrated.
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paper_title: High-speed nondirective optical communication for wireless networks

paper_content:

The primary obstacles to high-speed communication, namely, shot noise from ambient light, high-capacitance photodiodes and multipath dispersion, are reviewed, and ways to counter them are demonstrated for a prototypical infrared system. The discussion is limited to the physical-layer issues involved in the design of a single high-speed optical link. The focus is on the downlink (from base station to portable), which is a more challenging problem technically than the uplink for two reasons. First, the complexity of the portable receiver is much more constrained than that of the base station, due to power consumption and cost restrictions. Second, the downlink data rates are likely to be much higher than the uplink rates, because downlink communication will include downloading large executable files and possibly video services, whereas uplink communication will be used for transferring working files and keyboard commands which tend to be much smaller. >
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paper_title: Optical wireless: the story so far

paper_content:

We present a broad review of the optical wireless field, from early experiments through to today's high-performance systems. Emphasis is placed on understanding the benefits and limitations of optical wireless, all of which ultimately define the applications. A variety of systems are examined, each incorporating a different technological solution to suit the particular application.
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paper_title: Simulation of Multipath Impulse Response for Indoor Wireless Optical Channels

paper_content:

A recursive method for evaluating the impulse response of an indoor free-space optical channel with Lambertian reflectors is presented. The method, which accounts for multiple reflections of any order, enables accurate analysis of the effects of multipath dispersion on high-speed indoor optical communication systems. A simple algorithm for computer implementation of the technique and computer simulation results for both line-of-sight and diffuse transmitter configurations are also presented. In both cases, it is shown that reflections of multiple order are a significant source of intersymbol interference. Experimental measurements of optical multipath, which help verify the accuracy of the simulations, are discussed. >
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paper_title: Optical wireless: the story so far

paper_content:

We present a broad review of the optical wireless field, from early experiments through to today's high-performance systems. Emphasis is placed on understanding the benefits and limitations of optical wireless, all of which ultimately define the applications. A variety of systems are examined, each incorporating a different technological solution to suit the particular application.
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paper_title: Simulation of Multipath Impulse Response for Indoor Wireless Optical Channels

paper_content:

A recursive method for evaluating the impulse response of an indoor free-space optical channel with Lambertian reflectors is presented. The method, which accounts for multiple reflections of any order, enables accurate analysis of the effects of multipath dispersion on high-speed indoor optical communication systems. A simple algorithm for computer implementation of the technique and computer simulation results for both line-of-sight and diffuse transmitter configurations are also presented. In both cases, it is shown that reflections of multiple order are a significant source of intersymbol interference. Experimental measurements of optical multipath, which help verify the accuracy of the simulations, are discussed. >
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paper_title: Wireless LANs: physical properties of infra-red systems vs. mmw systems

paper_content:

Interest in wireless indoor communications has been spectacular. As we tend to need relatively broad bandwidths for such communication, the choice of carrier frequency would seem to be between the millimeter-wave/upper microwave bands and infra-red. The authors consider those systems which operate with one cell or multiple cells within a room. Such systems in the longer term must offer speeds compatible with fiber distributed data interface (FDDI) or the integrated broadband communications network (IBCN). Keeping this in mind, the authors look at the capability of systems supporting transmission rates of 100 Mb/s, though of course useful networks can be realized with much lower single user data transfer rates. As with mmw, infrared (IR) radiation is essentially restricted to the room in which it is generated; apart from leakage through windows and doors it will not normally be detected outside a room and should not interfere significantly with similar systems in neighboring offices. However, IR is not suitable for operation in very large rooms. In addition it is seen that mmw offers certain advantages in both large and small rooms. >
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paper_title: Optical wireless: the story so far

paper_content:

We present a broad review of the optical wireless field, from early experiments through to today's high-performance systems. Emphasis is placed on understanding the benefits and limitations of optical wireless, all of which ultimately define the applications. A variety of systems are examined, each incorporating a different technological solution to suit the particular application.
---
paper_title: Optical wireless: the story so far

paper_content:

We present a broad review of the optical wireless field, from early experiments through to today's high-performance systems. Emphasis is placed on understanding the benefits and limitations of optical wireless, all of which ultimately define the applications. A variety of systems are examined, each incorporating a different technological solution to suit the particular application.
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paper_title: Holograms for optical wireless LANs

paper_content:

The authors investigate the use of holographic transmitters in optical wireless local area networks. Holograms allow more optical power to be launched safely, leading to commensurate improvements in system range and performance. The authors assess the hologram performance, make comparison with theoretical predictions and quantify the improvement provided by holograms.
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paper_title: Performance of infrared transmission systems under ambient light interference

paper_content:

Optical transmission systems are mainly impaired by the shot noise induced by ambient light, the transmitted optical power limitations (high path losses), the channel bandwidth limitations owing to multipath dispersion and the interference produced by artificial light sources. Several modulation and encoding schemes have been proposed for this channel and their performance has been studied and presented by several authors while neglecting the effects of the artificial light interference. The work reported extends the previous analysis by taking into account the optical power penalty induced by artificial light interference. An analytical approach is used to estimate this. In practical systems, the effect of the interference is usually mitigated using electrical highpass filters. In the paper the combined effect of interference and highpass filter is evaluated. The presented results show that the interference produced by fluorescent lamps driven by electronic ballasts induce high power penalties in OOK and L-PPM systems, even when electrical highpass filtering is used, for data rates up to 10 Mbit/s. For the interference produced by incandescent lamps and fluorescent lamps driven by conventional ballasts, the power penalty induced in OOK systems can be effectively reduced using highpass filtering, while PPM is very tolerant to that interference even without any highpass filtering. The major conclusion is that artificial light interference have to he considered both in system design and performance evaluation.
---
paper_title: Indoor ambient light noise and its effect on wireless optical links

paper_content:

Knowledge of ambient optical noise is essential for designers of free space optical links, for designing resilient circuits. An experimental characterisation of the most commonly encountered ambient optical radiation is presented. The study includes tungsten filament sources, low and high frequency fluorescent lights, IR headphones, TV remote controls and daylight. Practical means to reduce their influence on the performance of the links are also given. The results are also valuable for setting a standard way of comparing wireless IR links, based on testing their performance under such ambient noise.
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paper_title: Performance of pulse-position modulation on measured non-directed indoor infrared channels

paper_content:

We examine the performance of pulse-position modulation (PPM) on measured channels with intersymbol interference (ISI). We summarize the bit-error-rate performance of unequalized systems and review the performance of maximum-likelihood sequence detection (MLSD) for PPM over ISI channels with additive white Gaussian noise. We evaluate the performance of PPM links over 46 experimentally measured indoor infrared channels. Detailed results are presented for 2, 4, 8, and 16-PPM at bit rates of 10 Mb/s and 30 Mb/s, and these techniques are compared to on-off keying. Our results show that when MLSD is employed, 16-PPM provides the best average-power efficiency among the modulation techniques considered in this study.
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paper_title: Multiple-subcarrier modulation for non-directed wireless infrared communication

paper_content:

We examine multiple-subcarrier modulation (MSM) schemes for wireless infrared digital communication in the indoor environment. Intensity modulation with direct detection (IM/DD) is employed, which results in equivalent baseband channels with a nonnegativity constraint on the input. The power efficiencies of modulation schemes are compared at 30 Mb/s and 100 Mb/s over an ensemble of experimentally determined multipath channels. Carrier selection and power shaping are examined as methods for improving MSM performance. It is found that MSM schemes can allow operation at higher data rates than single-carrier modulation schemes without equalization. Moreover, MSM schemes can be more bandwidth-efficient and also can provide a simple and flexible method for multiple access to the channel. However, they are not as power efficient as single-carrier schemes, and this will limit their use to applications which are not power limited.
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paper_title: Differential pulse-position modulation for power-efficient optical communication

paper_content:

We examine the use of differential pulse-position modulation (DPPM) for optical communication systems using intensity modulation with direct detection in the presence of additive white Gaussian noise. We present expressions for the error probability and power spectral density of DPPM. We show that for a given bandwidth, DPPM requires significantly less average power than pulse position modulation (PPM). We also examine the performance of DPPM in the presence of multipath intersymbol interference (ISI). We find that the ISI penalties incurred by PPM and DPPM exhibit very similar dependencies upon the channel RMS delay spread. We discuss the use of chip-rate and multichip-rate equalization to combat ISI. Finally, we describe potential problems caused by the nonuniform bit-rate characteristic of DPPM, and we propose several solutions.
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paper_title: Trellis-coded pulse-position modulation for indoor wireless infrared communications

paper_content:

We analyze the performance of trellis-coded pulse-position modulation (PPM) on indoor, wireless infrared channels. We show that maximum-likelihood sequence detection (MLSD) of trellis-coded PPM is very effective in mitigating the multipath dispersion on such channels. We present code search results for high constraint-length, rate-2/3, 8-PPM and rate-3/4, 16-PPM codes. We provide bit-error-rate curves and intersymbol interference power penalties for MLSD of PPM with these codes, evaluated on ceiling-bounce channel models with delay spread per bit duration ratios of 0.02 to 0.3. Finally, we present Monte Carlo simulation results to verify our analysis.
---
paper_title: Performance of infrared transmission systems under ambient light interference

paper_content:

Optical transmission systems are mainly impaired by the shot noise induced by ambient light, the transmitted optical power limitations (high path losses), the channel bandwidth limitations owing to multipath dispersion and the interference produced by artificial light sources. Several modulation and encoding schemes have been proposed for this channel and their performance has been studied and presented by several authors while neglecting the effects of the artificial light interference. The work reported extends the previous analysis by taking into account the optical power penalty induced by artificial light interference. An analytical approach is used to estimate this. In practical systems, the effect of the interference is usually mitigated using electrical highpass filters. In the paper the combined effect of interference and highpass filter is evaluated. The presented results show that the interference produced by fluorescent lamps driven by electronic ballasts induce high power penalties in OOK and L-PPM systems, even when electrical highpass filtering is used, for data rates up to 10 Mbit/s. For the interference produced by incandescent lamps and fluorescent lamps driven by conventional ballasts, the power penalty induced in OOK systems can be effectively reduced using highpass filtering, while PPM is very tolerant to that interference even without any highpass filtering. The major conclusion is that artificial light interference have to he considered both in system design and performance evaluation.
---
paper_title: Performance of pulse-position modulation on measured non-directed indoor infrared channels

paper_content:

We examine the performance of pulse-position modulation (PPM) on measured channels with intersymbol interference (ISI). We summarize the bit-error-rate performance of unequalized systems and review the performance of maximum-likelihood sequence detection (MLSD) for PPM over ISI channels with additive white Gaussian noise. We evaluate the performance of PPM links over 46 experimentally measured indoor infrared channels. Detailed results are presented for 2, 4, 8, and 16-PPM at bit rates of 10 Mb/s and 30 Mb/s, and these techniques are compared to on-off keying. Our results show that when MLSD is employed, 16-PPM provides the best average-power efficiency among the modulation techniques considered in this study.
---
paper_title: Trellis-coded pulse-position modulation for indoor wireless infrared communications

paper_content:

We analyze the performance of trellis-coded pulse-position modulation (PPM) on indoor, wireless infrared channels. We show that maximum-likelihood sequence detection (MLSD) of trellis-coded PPM is very effective in mitigating the multipath dispersion on such channels. We present code search results for high constraint-length, rate-2/3, 8-PPM and rate-3/4, 16-PPM codes. We provide bit-error-rate curves and intersymbol interference power penalties for MLSD of PPM with these codes, evaluated on ceiling-bounce channel models with delay spread per bit duration ratios of 0.02 to 0.3. Finally, we present Monte Carlo simulation results to verify our analysis.
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paper_title: Differential pulse-position modulation for power-efficient optical communication

paper_content:

We examine the use of differential pulse-position modulation (DPPM) for optical communication systems using intensity modulation with direct detection in the presence of additive white Gaussian noise. We present expressions for the error probability and power spectral density of DPPM. We show that for a given bandwidth, DPPM requires significantly less average power than pulse position modulation (PPM). We also examine the performance of DPPM in the presence of multipath intersymbol interference (ISI). We find that the ISI penalties incurred by PPM and DPPM exhibit very similar dependencies upon the channel RMS delay spread. We discuss the use of chip-rate and multichip-rate equalization to combat ISI. Finally, we describe potential problems caused by the nonuniform bit-rate characteristic of DPPM, and we propose several solutions.
---
paper_title: Trellis-coded pulse-position modulation for indoor wireless infrared communications

paper_content:

We analyze the performance of trellis-coded pulse-position modulation (PPM) on indoor, wireless infrared channels. We show that maximum-likelihood sequence detection (MLSD) of trellis-coded PPM is very effective in mitigating the multipath dispersion on such channels. We present code search results for high constraint-length, rate-2/3, 8-PPM and rate-3/4, 16-PPM codes. We provide bit-error-rate curves and intersymbol interference power penalties for MLSD of PPM with these codes, evaluated on ceiling-bounce channel models with delay spread per bit duration ratios of 0.02 to 0.3. Finally, we present Monte Carlo simulation results to verify our analysis.
---
paper_title: Performance of infrared transmission systems under ambient light interference

paper_content:

Optical transmission systems are mainly impaired by the shot noise induced by ambient light, the transmitted optical power limitations (high path losses), the channel bandwidth limitations owing to multipath dispersion and the interference produced by artificial light sources. Several modulation and encoding schemes have been proposed for this channel and their performance has been studied and presented by several authors while neglecting the effects of the artificial light interference. The work reported extends the previous analysis by taking into account the optical power penalty induced by artificial light interference. An analytical approach is used to estimate this. In practical systems, the effect of the interference is usually mitigated using electrical highpass filters. In the paper the combined effect of interference and highpass filter is evaluated. The presented results show that the interference produced by fluorescent lamps driven by electronic ballasts induce high power penalties in OOK and L-PPM systems, even when electrical highpass filtering is used, for data rates up to 10 Mbit/s. For the interference produced by incandescent lamps and fluorescent lamps driven by conventional ballasts, the power penalty induced in OOK systems can be effectively reduced using highpass filtering, while PPM is very tolerant to that interference even without any highpass filtering. The major conclusion is that artificial light interference have to he considered both in system design and performance evaluation.
---
paper_title: Multiple-subcarrier modulation for non-directed wireless infrared communication

paper_content:

We examine multiple-subcarrier modulation (MSM) schemes for wireless infrared digital communication in the indoor environment. Intensity modulation with direct detection (IM/DD) is employed, which results in equivalent baseband channels with a nonnegativity constraint on the input. The power efficiencies of modulation schemes are compared at 30 Mb/s and 100 Mb/s over an ensemble of experimentally determined multipath channels. Carrier selection and power shaping are examined as methods for improving MSM performance. It is found that MSM schemes can allow operation at higher data rates than single-carrier modulation schemes without equalization. Moreover, MSM schemes can be more bandwidth-efficient and also can provide a simple and flexible method for multiple access to the channel. However, they are not as power efficient as single-carrier schemes, and this will limit their use to applications which are not power limited.
---
paper_title: Performance of infrared transmission systems under ambient light interference

paper_content:

Optical transmission systems are mainly impaired by the shot noise induced by ambient light, the transmitted optical power limitations (high path losses), the channel bandwidth limitations owing to multipath dispersion and the interference produced by artificial light sources. Several modulation and encoding schemes have been proposed for this channel and their performance has been studied and presented by several authors while neglecting the effects of the artificial light interference. The work reported extends the previous analysis by taking into account the optical power penalty induced by artificial light interference. An analytical approach is used to estimate this. In practical systems, the effect of the interference is usually mitigated using electrical highpass filters. In the paper the combined effect of interference and highpass filter is evaluated. The presented results show that the interference produced by fluorescent lamps driven by electronic ballasts induce high power penalties in OOK and L-PPM systems, even when electrical highpass filtering is used, for data rates up to 10 Mbit/s. For the interference produced by incandescent lamps and fluorescent lamps driven by conventional ballasts, the power penalty induced in OOK systems can be effectively reduced using highpass filtering, while PPM is very tolerant to that interference even without any highpass filtering. The major conclusion is that artificial light interference have to he considered both in system design and performance evaluation.
---
paper_title: Performance of infrared transmission systems under ambient light interference

paper_content:

Optical transmission systems are mainly impaired by the shot noise induced by ambient light, the transmitted optical power limitations (high path losses), the channel bandwidth limitations owing to multipath dispersion and the interference produced by artificial light sources. Several modulation and encoding schemes have been proposed for this channel and their performance has been studied and presented by several authors while neglecting the effects of the artificial light interference. The work reported extends the previous analysis by taking into account the optical power penalty induced by artificial light interference. An analytical approach is used to estimate this. In practical systems, the effect of the interference is usually mitigated using electrical highpass filters. In the paper the combined effect of interference and highpass filter is evaluated. The presented results show that the interference produced by fluorescent lamps driven by electronic ballasts induce high power penalties in OOK and L-PPM systems, even when electrical highpass filtering is used, for data rates up to 10 Mbit/s. For the interference produced by incandescent lamps and fluorescent lamps driven by conventional ballasts, the power penalty induced in OOK systems can be effectively reduced using highpass filtering, while PPM is very tolerant to that interference even without any highpass filtering. The major conclusion is that artificial light interference have to he considered both in system design and performance evaluation.
---
paper_title: Performance of infrared transmission systems under ambient light interference

paper_content:

Optical transmission systems are mainly impaired by the shot noise induced by ambient light, the transmitted optical power limitations (high path losses), the channel bandwidth limitations owing to multipath dispersion and the interference produced by artificial light sources. Several modulation and encoding schemes have been proposed for this channel and their performance has been studied and presented by several authors while neglecting the effects of the artificial light interference. The work reported extends the previous analysis by taking into account the optical power penalty induced by artificial light interference. An analytical approach is used to estimate this. In practical systems, the effect of the interference is usually mitigated using electrical highpass filters. In the paper the combined effect of interference and highpass filter is evaluated. The presented results show that the interference produced by fluorescent lamps driven by electronic ballasts induce high power penalties in OOK and L-PPM systems, even when electrical highpass filtering is used, for data rates up to 10 Mbit/s. For the interference produced by incandescent lamps and fluorescent lamps driven by conventional ballasts, the power penalty induced in OOK systems can be effectively reduced using highpass filtering, while PPM is very tolerant to that interference even without any highpass filtering. The major conclusion is that artificial light interference have to he considered both in system design and performance evaluation.
---
paper_title: Performance of infrared transmission systems under ambient light interference

paper_content:

Optical transmission systems are mainly impaired by the shot noise induced by ambient light, the transmitted optical power limitations (high path losses), the channel bandwidth limitations owing to multipath dispersion and the interference produced by artificial light sources. Several modulation and encoding schemes have been proposed for this channel and their performance has been studied and presented by several authors while neglecting the effects of the artificial light interference. The work reported extends the previous analysis by taking into account the optical power penalty induced by artificial light interference. An analytical approach is used to estimate this. In practical systems, the effect of the interference is usually mitigated using electrical highpass filters. In the paper the combined effect of interference and highpass filter is evaluated. The presented results show that the interference produced by fluorescent lamps driven by electronic ballasts induce high power penalties in OOK and L-PPM systems, even when electrical highpass filtering is used, for data rates up to 10 Mbit/s. For the interference produced by incandescent lamps and fluorescent lamps driven by conventional ballasts, the power penalty induced in OOK systems can be effectively reduced using highpass filtering, while PPM is very tolerant to that interference even without any highpass filtering. The major conclusion is that artificial light interference have to he considered both in system design and performance evaluation.
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paper_title: Wireless Information Networks

paper_content:

Preface. PART I INTRODUCTION TO WIRELESS NETWORKS. 1 Overview of Wireless Networks. 1.1 Introduction. 1.2 Network Architecture and Design Issues. 1.3 Key Trends in Wireless Networking. 1.4 Outline of the Book. Questions. 2 Evolution of the Wireless Industry. 2.1 Introduction. 2.2 Three Views of the Wireless Industry. 2.3 Three Generations of Cellular Networks. 2.4 Trends in Wireless Technologies. Questions. PART II CHARACTERISTICS OF RADIO PROPAGATION. 3 Characterization of Radio Propagation. 3.1 Introduction. 3.2 Multipath Fading and the Distance-Power Relationship. 3.3 Local Movements and Doppler Shift. 3.4 Multipath for Wideband Signals. 3.5 Classical Uncorrelated Scattering Model. 3.6 Indoor and Urban Radio Propagation Modeling. Questions. Problems. Projects. 4 Modeling and Simulation of Narrowband Signal Characteristics. 4.1 Introduction. 4.2 Modeling Path Loss and Slow Shadow Fading. 4.3 Doppler Spectrum of Fast Envelope Fading. 4.4 Statistical Behavior of Fast Envelope Fading. 4.5 Simulation of Fast Envelope Fading. Questions. Problems. Projects. 5 Measurement of Wideband and UWB Channel Characteristics. 5.1 Introduction. 5.2 Time-Domain Measurement Techniques. 5.3 Frequency-Domain Measurement Techniques. 5.4 Advances in Frequency-Domain Channel Measurement. Questions. Problems. Project. 6 Modeling of Wideband Radio Channel Characteristics. 6.1 Introduction. 6.2 Wideband Time-Domain Statistical Modeling. 6.3 Wideband Frequency-Domain Channel Modeling. 6.4 Comparison Between Statistical Models. 6.5 Ray-Tracing Algorithms. 6.6 Direct Solution of Radio Propagation Equations. 6.7 Comparison of Deterministic and Statistical Modeling. 6.8 Site-Specific Statistical Model. Appendix 6A: GSM-Recommended Multipath Propagation Models. Appendix 6B: Wideband Multipath Propagation Models. Questions. Problems. Projects. PART III MODEM DESIGN. 7 Narrowband Modem Technology. 7.1 Introduction. 7.2 Basic Modulation Techniques. 7.3 Theoretical Limits and Practical Impairments. 7.4 Traditional Modems for Wide-Area Wireless Networks. 7.5 Other Aspects of Modem Implementation. Questions. Problems. Projects. 8 Fading, Diversity, and Coding. 8.1 Introduction. 8.2 Radio Communication on Flat Rayleigh Fading Channels. 8.3 Diversity Combining. 8.4 Error-Control Coding for Wireless Channels. 8.5 Space-Time Coding. 8.6 MIMO and STC. Questions. Problems. Projects. 9 Broadband Modem Technologies. 9.1 Introduction. 9.2 Effects of Frequency-Selective Multipath Fading. 9.3 Discrete Multipath Fading Channel Model. 9.4 Adaptive Discrete Matched Filter. 9.5 Adaptive Equalization. 9.6 Sectored Antennas. 9.7 Multicarrier, OFDM, and Frequency Diversity. 9.8 Comparison of Traditional Broadband Modems. 9.9 MIMO in Frequency-Selective Fading. Appendix 9A: Analysis of the Equalizers. Questions. Problems. Projects. 10 Spread-Spectrum and CDMA Technology. 10.1 Introduction. 10.2 Principles of Frequency-Hopping Spread Spectrum. 10.3 Principles of Direct-Sequence Spread Spectrum. 10.4 Interference in Spread-Spectrum Systems. 10.5 Performance of CDMA Systems. Questions. Problems. PART IV SYSTEMS ASPECTS. 11 Topology, Medium Access, and Performance. 11.1 Introduction. 11.2 Topologies for Local Networks. 11.3 Cellular Topology for Wide-Area Networks. 11.4 Centrally Controlled Assigned Access Methods. 11.5 Distributed Contention-Based Access Control. Questions. Problems. Project. 12 Ultrawideband Communications. 12.1 Introduction. 12.2 UWB Channel Characteristics. 12.3 Impulse Radio and Time-Hopping Access. 12.4 Direct-Sequence UWB. 12.5 Multiband OFDM. Questions. Problems. 13 RF Location Sensing. 13.1 Introduction. 13.2 RF Location-Sensing Techniques. 13.3 Modeling The Behavior of RF Sensors. 13.4 Wireless Positioning Algorithms. Questions. Problems. 14 Wireless Optical Networks. 14.1 Introduction. 14.2 Implementation. 14.3 Eye Safety. 14.4 IR Channel Characterization and Data-Rate Limitations. 14.5 Modulation Techniques for Optical Communications. 14.6 Multiple Access and Data Rate. Questions. 15 Systems and Standards. 15.1 Introduction. 15.2 GSM, GPRS, and EDGE. 15.3 CDMA and HDR. 15.4 Other Historical Systems. 15.5 Wireless LANs. 15.6 Speech Coding in Wireless Systems. Questions. References. Index. About the Authors.
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paper_title: Wireless Information Networks

paper_content:

Preface. PART I INTRODUCTION TO WIRELESS NETWORKS. 1 Overview of Wireless Networks. 1.1 Introduction. 1.2 Network Architecture and Design Issues. 1.3 Key Trends in Wireless Networking. 1.4 Outline of the Book. Questions. 2 Evolution of the Wireless Industry. 2.1 Introduction. 2.2 Three Views of the Wireless Industry. 2.3 Three Generations of Cellular Networks. 2.4 Trends in Wireless Technologies. Questions. PART II CHARACTERISTICS OF RADIO PROPAGATION. 3 Characterization of Radio Propagation. 3.1 Introduction. 3.2 Multipath Fading and the Distance-Power Relationship. 3.3 Local Movements and Doppler Shift. 3.4 Multipath for Wideband Signals. 3.5 Classical Uncorrelated Scattering Model. 3.6 Indoor and Urban Radio Propagation Modeling. Questions. Problems. Projects. 4 Modeling and Simulation of Narrowband Signal Characteristics. 4.1 Introduction. 4.2 Modeling Path Loss and Slow Shadow Fading. 4.3 Doppler Spectrum of Fast Envelope Fading. 4.4 Statistical Behavior of Fast Envelope Fading. 4.5 Simulation of Fast Envelope Fading. Questions. Problems. Projects. 5 Measurement of Wideband and UWB Channel Characteristics. 5.1 Introduction. 5.2 Time-Domain Measurement Techniques. 5.3 Frequency-Domain Measurement Techniques. 5.4 Advances in Frequency-Domain Channel Measurement. Questions. Problems. Project. 6 Modeling of Wideband Radio Channel Characteristics. 6.1 Introduction. 6.2 Wideband Time-Domain Statistical Modeling. 6.3 Wideband Frequency-Domain Channel Modeling. 6.4 Comparison Between Statistical Models. 6.5 Ray-Tracing Algorithms. 6.6 Direct Solution of Radio Propagation Equations. 6.7 Comparison of Deterministic and Statistical Modeling. 6.8 Site-Specific Statistical Model. Appendix 6A: GSM-Recommended Multipath Propagation Models. Appendix 6B: Wideband Multipath Propagation Models. Questions. Problems. Projects. PART III MODEM DESIGN. 7 Narrowband Modem Technology. 7.1 Introduction. 7.2 Basic Modulation Techniques. 7.3 Theoretical Limits and Practical Impairments. 7.4 Traditional Modems for Wide-Area Wireless Networks. 7.5 Other Aspects of Modem Implementation. Questions. Problems. Projects. 8 Fading, Diversity, and Coding. 8.1 Introduction. 8.2 Radio Communication on Flat Rayleigh Fading Channels. 8.3 Diversity Combining. 8.4 Error-Control Coding for Wireless Channels. 8.5 Space-Time Coding. 8.6 MIMO and STC. Questions. Problems. Projects. 9 Broadband Modem Technologies. 9.1 Introduction. 9.2 Effects of Frequency-Selective Multipath Fading. 9.3 Discrete Multipath Fading Channel Model. 9.4 Adaptive Discrete Matched Filter. 9.5 Adaptive Equalization. 9.6 Sectored Antennas. 9.7 Multicarrier, OFDM, and Frequency Diversity. 9.8 Comparison of Traditional Broadband Modems. 9.9 MIMO in Frequency-Selective Fading. Appendix 9A: Analysis of the Equalizers. Questions. Problems. Projects. 10 Spread-Spectrum and CDMA Technology. 10.1 Introduction. 10.2 Principles of Frequency-Hopping Spread Spectrum. 10.3 Principles of Direct-Sequence Spread Spectrum. 10.4 Interference in Spread-Spectrum Systems. 10.5 Performance of CDMA Systems. Questions. Problems. PART IV SYSTEMS ASPECTS. 11 Topology, Medium Access, and Performance. 11.1 Introduction. 11.2 Topologies for Local Networks. 11.3 Cellular Topology for Wide-Area Networks. 11.4 Centrally Controlled Assigned Access Methods. 11.5 Distributed Contention-Based Access Control. Questions. Problems. Project. 12 Ultrawideband Communications. 12.1 Introduction. 12.2 UWB Channel Characteristics. 12.3 Impulse Radio and Time-Hopping Access. 12.4 Direct-Sequence UWB. 12.5 Multiband OFDM. Questions. Problems. 13 RF Location Sensing. 13.1 Introduction. 13.2 RF Location-Sensing Techniques. 13.3 Modeling The Behavior of RF Sensors. 13.4 Wireless Positioning Algorithms. Questions. Problems. 14 Wireless Optical Networks. 14.1 Introduction. 14.2 Implementation. 14.3 Eye Safety. 14.4 IR Channel Characterization and Data-Rate Limitations. 14.5 Modulation Techniques for Optical Communications. 14.6 Multiple Access and Data Rate. Questions. 15 Systems and Standards. 15.1 Introduction. 15.2 GSM, GPRS, and EDGE. 15.3 CDMA and HDR. 15.4 Other Historical Systems. 15.5 Wireless LANs. 15.6 Speech Coding in Wireless Systems. Questions. References. Index. About the Authors.
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paper_title: Performance of infrared transmission systems under ambient light interference

paper_content:

Optical transmission systems are mainly impaired by the shot noise induced by ambient light, the transmitted optical power limitations (high path losses), the channel bandwidth limitations owing to multipath dispersion and the interference produced by artificial light sources. Several modulation and encoding schemes have been proposed for this channel and their performance has been studied and presented by several authors while neglecting the effects of the artificial light interference. The work reported extends the previous analysis by taking into account the optical power penalty induced by artificial light interference. An analytical approach is used to estimate this. In practical systems, the effect of the interference is usually mitigated using electrical highpass filters. In the paper the combined effect of interference and highpass filter is evaluated. The presented results show that the interference produced by fluorescent lamps driven by electronic ballasts induce high power penalties in OOK and L-PPM systems, even when electrical highpass filtering is used, for data rates up to 10 Mbit/s. For the interference produced by incandescent lamps and fluorescent lamps driven by conventional ballasts, the power penalty induced in OOK systems can be effectively reduced using highpass filtering, while PPM is very tolerant to that interference even without any highpass filtering. The major conclusion is that artificial light interference have to he considered both in system design and performance evaluation.
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paper_title: Wireless Information Networks

paper_content:

Preface. PART I INTRODUCTION TO WIRELESS NETWORKS. 1 Overview of Wireless Networks. 1.1 Introduction. 1.2 Network Architecture and Design Issues. 1.3 Key Trends in Wireless Networking. 1.4 Outline of the Book. Questions. 2 Evolution of the Wireless Industry. 2.1 Introduction. 2.2 Three Views of the Wireless Industry. 2.3 Three Generations of Cellular Networks. 2.4 Trends in Wireless Technologies. Questions. PART II CHARACTERISTICS OF RADIO PROPAGATION. 3 Characterization of Radio Propagation. 3.1 Introduction. 3.2 Multipath Fading and the Distance-Power Relationship. 3.3 Local Movements and Doppler Shift. 3.4 Multipath for Wideband Signals. 3.5 Classical Uncorrelated Scattering Model. 3.6 Indoor and Urban Radio Propagation Modeling. Questions. Problems. Projects. 4 Modeling and Simulation of Narrowband Signal Characteristics. 4.1 Introduction. 4.2 Modeling Path Loss and Slow Shadow Fading. 4.3 Doppler Spectrum of Fast Envelope Fading. 4.4 Statistical Behavior of Fast Envelope Fading. 4.5 Simulation of Fast Envelope Fading. Questions. Problems. Projects. 5 Measurement of Wideband and UWB Channel Characteristics. 5.1 Introduction. 5.2 Time-Domain Measurement Techniques. 5.3 Frequency-Domain Measurement Techniques. 5.4 Advances in Frequency-Domain Channel Measurement. Questions. Problems. Project. 6 Modeling of Wideband Radio Channel Characteristics. 6.1 Introduction. 6.2 Wideband Time-Domain Statistical Modeling. 6.3 Wideband Frequency-Domain Channel Modeling. 6.4 Comparison Between Statistical Models. 6.5 Ray-Tracing Algorithms. 6.6 Direct Solution of Radio Propagation Equations. 6.7 Comparison of Deterministic and Statistical Modeling. 6.8 Site-Specific Statistical Model. Appendix 6A: GSM-Recommended Multipath Propagation Models. Appendix 6B: Wideband Multipath Propagation Models. Questions. Problems. Projects. PART III MODEM DESIGN. 7 Narrowband Modem Technology. 7.1 Introduction. 7.2 Basic Modulation Techniques. 7.3 Theoretical Limits and Practical Impairments. 7.4 Traditional Modems for Wide-Area Wireless Networks. 7.5 Other Aspects of Modem Implementation. Questions. Problems. Projects. 8 Fading, Diversity, and Coding. 8.1 Introduction. 8.2 Radio Communication on Flat Rayleigh Fading Channels. 8.3 Diversity Combining. 8.4 Error-Control Coding for Wireless Channels. 8.5 Space-Time Coding. 8.6 MIMO and STC. Questions. Problems. Projects. 9 Broadband Modem Technologies. 9.1 Introduction. 9.2 Effects of Frequency-Selective Multipath Fading. 9.3 Discrete Multipath Fading Channel Model. 9.4 Adaptive Discrete Matched Filter. 9.5 Adaptive Equalization. 9.6 Sectored Antennas. 9.7 Multicarrier, OFDM, and Frequency Diversity. 9.8 Comparison of Traditional Broadband Modems. 9.9 MIMO in Frequency-Selective Fading. Appendix 9A: Analysis of the Equalizers. Questions. Problems. Projects. 10 Spread-Spectrum and CDMA Technology. 10.1 Introduction. 10.2 Principles of Frequency-Hopping Spread Spectrum. 10.3 Principles of Direct-Sequence Spread Spectrum. 10.4 Interference in Spread-Spectrum Systems. 10.5 Performance of CDMA Systems. Questions. Problems. PART IV SYSTEMS ASPECTS. 11 Topology, Medium Access, and Performance. 11.1 Introduction. 11.2 Topologies for Local Networks. 11.3 Cellular Topology for Wide-Area Networks. 11.4 Centrally Controlled Assigned Access Methods. 11.5 Distributed Contention-Based Access Control. Questions. Problems. Project. 12 Ultrawideband Communications. 12.1 Introduction. 12.2 UWB Channel Characteristics. 12.3 Impulse Radio and Time-Hopping Access. 12.4 Direct-Sequence UWB. 12.5 Multiband OFDM. Questions. Problems. 13 RF Location Sensing. 13.1 Introduction. 13.2 RF Location-Sensing Techniques. 13.3 Modeling The Behavior of RF Sensors. 13.4 Wireless Positioning Algorithms. Questions. Problems. 14 Wireless Optical Networks. 14.1 Introduction. 14.2 Implementation. 14.3 Eye Safety. 14.4 IR Channel Characterization and Data-Rate Limitations. 14.5 Modulation Techniques for Optical Communications. 14.6 Multiple Access and Data Rate. Questions. 15 Systems and Standards. 15.1 Introduction. 15.2 GSM, GPRS, and EDGE. 15.3 CDMA and HDR. 15.4 Other Historical Systems. 15.5 Wireless LANs. 15.6 Speech Coding in Wireless Systems. Questions. References. Index. About the Authors.
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paper_title: Wireless in-house data communication via diffuse infrared radiation

paper_content:

A novel wireless broadcast/multi-access channel is described for flexibly interconnecting a cluster of data terminals located within the same room. The transmission medium is diffusively scattered infrared radiation at 950-nm wavelength. Transmission is low-to-medium speed and the range up to 50 m. Theoretical analysis indicates that the time dispersion limits the transmission bandwidth of the system to 260 Mbit ċ m/s, but background noise produced by ambient daylight reduces the transmission speed below 1 Mbit/s. The transmission properties of the diffuse optical channel are analyzed, and experimental digital links for baseband PCM at 125 kbit/s and PSK 64 kbit/s are demonstrated.
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paper_title: High-speed nondirective optical communication for wireless networks

paper_content:

The primary obstacles to high-speed communication, namely, shot noise from ambient light, high-capacitance photodiodes and multipath dispersion, are reviewed, and ways to counter them are demonstrated for a prototypical infrared system. The discussion is limited to the physical-layer issues involved in the design of a single high-speed optical link. The focus is on the downlink (from base station to portable), which is a more challenging problem technically than the uplink for two reasons. First, the complexity of the portable receiver is much more constrained than that of the base station, due to power consumption and cost restrictions. Second, the downlink data rates are likely to be much higher than the uplink rates, because downlink communication will include downloading large executable files and possibly video services, whereas uplink communication will be used for transferring working files and keyboard commands which tend to be much smaller. >
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Title: A Review on Indoor Optical Wireless Systems

Section 1: Introduction
Description 1: Introduce the topic of indoor optical wireless systems, their benefits, and potential issues. Outline the structure of the paper.

Section 2: System Overview
Description 2: Provide a historical background and the development of indoor optical wireless systems. Discuss the advancements in optoelectronic devices and their applications.

Section 3: An Indoor Optical Wireless System
Description 3: Describe the components and functioning of a typical indoor optical wireless system, including the transmitter, propagation medium, and receiver.

Section 4: Transmission Techniques
Description 4: Discuss various transmission techniques used in indoor optical wireless systems, such as directed beam infrared (DBIR), diffuse infrared (DFIR), and quasi-diffuse infrared (QDIR) radiation.

Section 5: Design Challenges
Description 5: Examine the major challenges in designing indoor optical wireless systems, such as achieving high signal-to-noise ratio, eye safety, interference from ambient light sources, and multipath characteristics.

Section 6: Modulation Techniques
Description 6: Review the different modulation techniques employed in indoor optical wireless systems, such as On-Off Keying (OOK), Pulse Modulation (PM), and Sub-carrier Modulation. Compare their power and bandwidth efficiencies.

Section 7: Multi-Access Techniques
Description 7: Explain the multi-access techniques used in indoor optical wireless systems, including optical and electrical multiplexing techniques like TDMA, FDMA, and CDMA.

Section 8: Wireless LAN Objectives
Description 8: Discuss the objectives of wireless LANs, their traditional implementations, and the need for wireless LANs in modern office environments.

Section 9: Optical Wireless LAN Technology
Description 9: Describe the classification and technical features of optical wireless LAN technology, highlighting the differences between DFIR, DBIR, and QDIR LANs.

Section 10: Standards for Indoor Optical Wireless Systems
Description 10: Detail the current standards for indoor optical wireless systems, including their development and specifications for interoperability and data rates.

Section 11: Conclusions
Description 11: Summarize the main findings of the review, discuss the future directions and potential research areas in indoor optical wireless systems.