Showing papers by "Alwyn J. Seeds published in 2008"
08 Dec 2008
TL;DR: A new method for estimating location of radio frequency identification (RFID) tags for application in indoor environments using a time-difference of arrival (TDOA) range estimation algorithm that has the potential to be used in accurate indoor location application.
Abstract: This paper introduces a new method for estimating location of radio frequency identification (RFID) tags for application in indoor environments. The proposed positioning scheme employs a time-difference of arrival (TDOA) range estimation algorithm. The time-difference measurement is performed by taking advantage of the de-ramp properties of a linear frequency modulation (LFM) chirp. The paper provides details of the mechanism of this LFM-TDOA scheme from the system point of view. Compared to other popular radio technologies in the indoor positioning field, this new scheme is easy to design and requires only moderate computation ability. According to the experiment results summarized in the paper, the LFM-TDOA system shows good range estimation accuracy and thus has the potential to be used in accurate indoor location application.
39 citations
05 Nov 2008
TL;DR: In this article, a phase quadrature double sideband frequency translation technique was proposed for MIMO radio signals over optical fiber, which employs fewer LO sources than SCM and does not require WDM.
Abstract: We propose and demonstrate transmission of MIMO radio signals over optical fibre using a novel phase quadrature double sideband frequency translation technique which employs fewer LO sources than SCM and does not require WDM.
15 citations
01 Dec 2008
TL;DR: In this paper, the authors present the prospects and technologies for integration in microwave photonic systems based on quantum well intermixing, monolithic integration on indium phosphide and hybrid integration using silicon motherboard technology.
Abstract: This paper reviews the prospects and technologies for integration in microwave photonic systems. An advanced application photonic THz generation is used to illustrate the potential value of photonic integration. Integration technologies for this system based on quantum well intermixing, monolithic integration on indium phosphide and hybrid integration using silicon motherboard technology are described. Finally, some pointers to future applications of integration are given.
11 citations
24 Feb 2008
TL;DR: The first homodyne coherent receiver with optical injection phase lock loop is reported, achieving phase-error variance of 5x10-3-3rad (1.5MHz linewidth) with 10Gb/s ASK data demodulated with BER.
Abstract: The first homodyne coherent receiver with optical injection phase lock loop is reported, achieving phase-error variance of 5x10-3rad2 (1.5MHz linewidth). 10Gb/s ASK data was demodulated with BER<;10-9 with an equal-power interfering signal at 25GHz offset.
11 citations
05 Nov 2008
TL;DR: The paper will present recent results on laser sources that could be used as the basis of the THz sources as well as a set of potential THz emitters such as the UTC photodiode which has already permitted up to 25 muW to be emitted at 1 THz.
Abstract: This paper presents a review of the recent development and research work on InP devices and their associated systems to generate and detect signal beyond 1 THz. The potential of the technology and the remaining challenges are also discussed. The paper will present recent results on laser sources that could be used as the basis of the THz sources as well as a set of potential THz emitters such as the UTC photodiode which has already permitted up to 25 muW to be emitted at 1 THz.
11 citations
TL;DR: In this article, the first millimeter-wave Gb/s transmission of broadband wireless signals using uncooled directly modulated lasers to give a low-cost solution has been demonstrated.
Abstract: We demonstrate the first millimeter-wave Gb/s transmission of broadband wireless signals using uncooled directly modulated lasers to give a low-cost solution. Data signals to and from the base station are distributed at intermediate frequencies for reduced chromatic dispersion together with a remote 40-GHz local oscillator signal for frequency upconversion/downconversion. Coarse-wavelength-division-multiplexing components are employed throughout the network allowing uncooled lasers and low cost filters to be used. Error-free transmission (BER < 10-9) has been achieved for the downlink and the uplink. The paper also provides detailed system link analysis together with simulation results.
9 citations
01 Jan 2008
TL;DR: In this paper, the first IEEE 802.11a wireless local area network (WLAN) data transmission using an electromagnetic bandgap (EBG) photonic antenna with an integrated InGaAs/AlInGaAs multiple quantum-well (MQW) asymmetric Fabry-Perot modulator/detector (AFPM) was reported.
Abstract: We report bidirectional link characterization and the first IEEE 802.11a wireless local area network (WLAN) data transmission using an electromagnetic bandgap (EBG) photonic antenna with an integrated InGaAs/AlInGaAs multiple quantum-well (MQW) asymmetric Fabry-Perot modulator/detector (AFPM). The dual-function AFPM performs as an optical intensity modulator on the uplink and as a conventional photodetector on the downlink in a single device. This new InGaAs/AlInGaAs AFPM device has also shown an improved modulation slope -dR/dV of 17%/V, where dR is the differential optical reflectance and dV is the differential terminal voltage, compared to the previously reported 6%/V achieved with an InGaAsP/InGaAsP MQW AFPM. Half-duplex IEEE 802.11a connection was successfully established between a laptop computer and the photonic antenna which in turn was connected via an optical fiber to a wireless access point. A maximum data throughput of 7 Mbps was achieved at 8-m separation between the laptop and the photonic antenna.
8 citations
05 Nov 2008
TL;DR: In this paper, the first fully bidirectional wireless data transmission of IEEE 802.11a wireless local area (WLAN) signals over fiber using uncooled directly modulated lasers was reported.
Abstract: In this paper, we report the first fully bidirectional wireless data transmission of IEEE802.11a Wireless Local Area (WLAN) signals over fibre using uncooled directly modulated lasers thus providing a low cost solution. A successful connection of IEEE802.11a was established between a mobile unit and the remote base station (BS) which in turn was connected via an optical fibre to the wireless access point. A maximum data throughput of 20 Mbps and 18 Mbps was achieved at a 10 m separation distance between the mobile unit and the BS antenna in the uplink and downlink directions respectively. Results are also presented for the data throughput performance of the system with varying free space distance and the measured average throughput in both transmission directions.
6 citations
TL;DR: In this paper, the first IEEE 802.11a wireless local area network (WLAN) data transmission using an electromagnetic bandgap (EBG) photonic antenna with an integrated InGaAs/AlInGaAs multiple quantum-well (MQW) asymmetric Fabry-Perot modulator/detector (AFPM) was reported.
Abstract: We report bidirectional link characterization and the first IEEE 802.11a wireless local area network (WLAN) data transmission using an electromagnetic bandgap (EBG) photonic antenna with an integrated InGaAs/AlInGaAs multiple quantum-well (MQW) asymmetric Fabry-Perot modulator/detector (AFPM). The dual-function AFPM performs as an optical intensity modulator on the uplink and as a conventional photodetector on the downlink in a single device. This new InGaAs/AlInGaAs AFPM device has also shown an improved modulation slope -dR/dV of 17%/V, where dR is the differential optical reflectance and dV is the differential terminal voltage, compared to the previously reported 6%/V achieved with an InGaAsP/InGaAsP MQW AFPM. Half-duplex IEEE 802.11a connection was successfully established between a laptop computer and the photonic antenna which in turn was connected via an optical fiber to a wireless access point. A maximum data throughput of 7 Mbps was achieved at 8-m separation between the laptop and the photonic antenna.
4 citations
25 Nov 2008
TL;DR: This tutorial will present the technologies used for radio over fibre systems, used to provide coverage for cellular radio and other wireless services in areas where direct reception is ineffective, such as within large buildings or underground.
Abstract: Radio over fibre systems can be used to provide coverage for cellular radio and other wireless services in areas where direct reception is ineffective, such as within large buildings or underground. This tutorial will present the technologies used for such systems.
3 citations
01 Dec 2008
TL;DR: In this article, the authors present a review of microwave-over-fiber systems, considering the basic performance parameters, and present recent work on such systems, including microwave photonic devices, and likely areas for future development.
Abstract: This chapter reviews the technologies involved in microwave-over-fiber systems, considering the basic performance parameters, and presents recent work on such systems. The low-loss, wide-bandwidth capability of optical transmission systems makes them attractive for the transmission and processing of microwave signals, while the development of high-capacity optical communication systems has required the import of microwave techniques in optical transmitters and receivers. Intensity modulation direct detection (IMDD) systems offer the advantage of simplicity. However, large received optical power is necessary to overcome receiver thermal noise. Following a summary of the historic development of the field and the development of microwave photonic devices, systems applications in telecommunications, and likely areas for future development are discussed in the chapter. The capability of coherent systems to select between many channels present on the same optical fiber makes them attractive in applications such as multiple antenna remoting. Among the applications reviewed are wireless-over-fiber access systems, broadband signal distribution and access systems, and communications antenna remoting systems. Of the applications for this technology, wireless-over-fiber systems and cable television transmission have both found widespread commercial adoption. The principal attraction of wireless-over-fiber technology is that it centralizes most of the transceiver functionality by transmitting the wireless signals in their modulated format over fiber and reduces the fielded access points to antennas with associated amplifiers and frequency converters. © 2008 Elsevier Inc. All rights reserved.
Proceedings Article•
01 Jan 2008TL;DR: The paper will present recent results on laser sources that could be used as the basis of the THz sources as well as a set of potential THz emitters such as the UTC photodiode which has already permitted up to 25 mu W to be emitted at 1 THz.
Abstract: This paper presents a review of the recent development and research work on InP devices and their associated systems to generate and detect signal beyond 1 THz. The potential of the technology and the remaining challenges am also discussed. The paper will present recent results on laser sources that could be used as the basis of the THz sources as well as a set of potential THz emitters such as the UTC photodiode which has already permitted up to 25 mu W to be emitted at 1 THz.
01 Jan 2008
TL;DR: In this paper, the authors demonstrate the first millimeter-wave Gb/s trans-mission mission of broadband wireless signals using uncooled directly modulated lasers to give a low-cost solution.
Abstract: We demonstrate the first millimeter-wave Gb/s trans- mission of broadband wireless signals using uncooled directly modulated lasers to give a low-cost solution. Data signals to and from the base station are distributed at intermediate frequencies for reduced chromatic dispersion together with a remote 40-GHz local oscillator signal for frequency upconversion/downconver- sion. Coarse-wavelength-division-multiplexing components are employed throughout the network allowing uncooled lasers and low cost filters to be used. Error-free transmission BER has been achieved for the downlink and the uplink. The paper also provides detailed system link analysis together with simulation results.