Communications and sensing of illumination contributions in a power led lighting system

Abstract — In recent years, LED technology emerged as a prime candidate for the future illumination light source, due to high energy efficiency and long life time. In addition, LEDs offer a superior flexibility in terms of colors and shapes, which leads to a potentially infinite variety of available light patterns. In order to create these patterns via easy user interaction, we need to sense the local light contribution of each LED. This measurement could be enabled through tagging of the light of each LED with unique embedded IDs. To this end, we propose a new modulation and multiple access scheme, named as codetime division multiple access- pulse position modulation (CTDMA-PPM): a form of PPM which is keyed according to a spreading sequence, and in which the duty cycle is subject to pulse width modulation (PWM) according to the required lighting setting. Our scheme considers illumination constraints in addition to the communication requirements and, to our best knowledge, it has not been addressed by other optical modulation methods. Based on the proposed modulation method and multiple access schemes, we develop a system structure, which includes illumination sources, a sensor receiver and a control system. Illumination sources illuminate the environment and transmit information, simultaneously. According to our theoretical analysis, this system structure could support a number of luminaries equal to the size of the CDMA codebook times the dimming range. I

On the Performance of Packet-Switched Cellular Networks for Wireless Data Communications

Cellular frequency reuse is known to be an efficient method to allow many wireless telephone subscribers to share the same frequency band. However, for wireless data and multi-media communications optimum cell layouts differ essentially from typical solutions for telephone systems. We argue that wireless radio systems for bursty message traffic preferably use the entire bandwidth in each cell. Packet queuing delays are derived for a network with multipath fading channels, shadowing, path loss and discontinuously transmitting base stations. Interference between cells can be reduced by appropriately scheduling transmissions or by `spatial collision resolution'

Single-channel IVHS Communication Architecture

This report documents a single-channel architecture offering two-way communication between vehicles and a fixed communication infrastructure. Part I discusses the technical advantages and disadvantages of a dedicated Intelligent Vehicle Highway Systems (IVHS) communications infrastructure versus the use of a hybrid system involving several existing communication networks. Aspects such as spectrum efficiency, message capacity, and network performance are described. Part II proposes a network architecture that offers several transmission services essential to IVHS communications, using only a single (30kHz) radio channel. This narrow bandwidth can accommodate datacasting, packet-switched transmission to and from the vehicle, collection of traffic data from probe vehicles and emergency messages. The proposed architecture may not have enough capacity to support a mature IVHS system, but it provides a scalable method to provide spectrum-efficient wireless access to packet data communications services

ImDerfect Sector Antenna Diversitv in

Abstract-In a wireless network with path loss and fading channels, receiver capture is known to substantially enhance the performance of the slotted ALOHA random access protocol. The efficiency of narrowband slotted ALOHA radio networks can be enhanced further by using sector antennas, each receiving signals from a particular segment of the network area. This paper investigates the effect of realistic, Le., partially overlapping antenna patterns and the resulting correlation of received power levels at different receiver branches. A method is derived for computing the joint throughput from two base station receivers with overlapping antennas patterns. The a posteriori informa-tion provided by the event of one message capturing one antenna is used to find conditional probabilities of capturing the other antennas as well. The paper shows that any overlap in the antenna patterns decreases the throughput, but transmissions from the overlapping area may face a larger probability of capture than signals from directions in which one antenna has maximum gain. I

Performance Analysis of Synchronous MC-CDMA in Mobile Rayleigh Channel with . . .

Rapid time variations of the mobile communication channel have a dramatic effect on the performance of multicarrier modulation. This paper models the Doppler spread and computes its effect on the bit error rate (BER) for multicarrier code division multiple access (MC-CDMA) transmission and compares it to orthogonal frequency division multiplexing (OFDM). Also, we evaluate the transmission capacity per subcarrier to quantify the potential of MC-CDMA and (coded-) OFDM. We focus on linear receivers, in particular those using the minimum mean-square error (MMSE) criterion. Our channel and system models allow the computation of analytical performance results. Simulations verify some commonly used, yet critical assumptions

Single-channel IVHS Communication Architecture

This report documents a single-channel architecture offering two-way communication between vehicles and a fixed communication infrastructure. Part I discusses the technical advantages and disadvantages of a dedicated Intelligent Vehicle Highway Systems (IVHS) communications infrastructure versus the use of a hybrid system involving several existing communication networks. Aspects such as spectrum efficiency, message capacity, and network performance are described. Part II proposes a network architecture that offers several transmission services essential to IVHS communications, using only a single (30kHz) radio channel. This narrow bandwidth can accommodate datacasting, packet-switched transmission to and from the vehicle, collection of traffic data from probe vehicles and emergency messages. The proposed architecture may not have enough capacity to support a mature IVHS system, but it provides a scalable method to provide spectrum-efficient wireless access to packet data communications services.Express highways--Automation, Intelligent Vehicle Highway Systems, Highway communications, System design

Spectrum Needs For IVHS

This report summarizes the need for (dedicated) radio spectrum for IVHS communication services. It concludes that, if efficient architectures can be developed, several MHz of spectrum will be needed for large-scale introduction of IVHS services. Compared to most other reported estimates of the spectrum requirements, this report gives a more detailed discussion of the relation between message volume (bit/sec), the required grade of service and spectral bandwidth (Hz)

Spectrum Needs For IVHS

This report summarizes the need for (dedicated) radio spectrum for IVHS communication services. It concludes that, if efficient architectures can be developed, several MHz of spectrum will be needed for large-scale introduction of IVHS services. Compared to most other reported estimates of the spectrum requirements, this report gives a more detailed discussion of the relation between message volume (bit/sec), the required grade of service and spectral bandwidth (Hz).Radio frequency, Intelligent Vehicle Highway Systems, Highway communications, route guidance