Measurements and Analysis of Secondary User Device Effects on Digital Television Receivers

This is the published version. Copyright © 2009 Newman et al.This article presents results from a study of the potential effects of secondary users operating in unoccupied television spectrum. Television spectrum is known within the wireless communications community as being underutilized, making it a prime candidate for dynamic spectrum access. The proposed use of this open spectrum has prompted questions concerning the quantity of available channel space that could be used without negative impact on consumers who view digital television broadcasts and the viability of secondary use of open channels immediately adjacent to a digital television broadcast channel. In this work, we investigate secondary device operation in the channels directly adjacent to a desired television channel, and the effects upon a selection of consumer digital television (DTV) receivers. Our observations strongly suggest that secondary users could operate "White Space Devices" (WSDs) in unoccupied channel bandwidth directly adjacent to a desired digital television (DTV) channel, with no observable adverse impact upon the reception of the desired channel content

Hybrid Optical Rf Airborne Communications

The use of hybrid free-space optical (FSO)/radio-frequency (RF) links to provide robust, high-throughput communications, fixed infrastructure links, and their associated networks have been thoroughly investigated for both commercial and military applications. The extension of this paradigm to mobile, long-range networks has long been a desire by the military communications community for multigigabit mobile backbone networks. The FSO communications subsystem has historically been the primary limitation. The challenge has been addressing the compensation of propagation effects and dynamic range of the received optical signal. This paper will address the various technologies required to compensate for the effects referenced above. We will outline the effects FSO and RF links experience and how we overcome these degradations. Results from field experiments conducted, including those from the Air Force Research Laboratory Integrated RF/Optical Networked Tactical Targeting Networking Technologies (IRON-T2) program, will be presented. © 2006 IEEE

Measurements and Analysis of Secondary User Device Effects on Digital Television Receivers

This article presents results from a study of the potential effects of secondary users operating in unoccupied television spectrum. Television spectrum is known within the wireless communications community as being underutilized, making it a prime candidate for dynamic spectrum access. The proposed use of this open spectrum has prompted questions concerning the quantity of available channel space that could be used without negative impact on consumers who view digital television broadcasts and the viability of secondary use of open channels immediately adjacent to a digital television broadcast channel. In this work, we investigate secondary device operation in the channels directly adjacent to a desired television channel, and the effects upon a selection of consumer digital television (DTV) receivers. Our observations strongly suggest that secondary users could operate “White Space Devices” (WSDs) in unoccupied channel bandwidth directly adjacent to a desired digital television (DTV) channel, with no observable adverse impact upon the reception of the desired channel content

Submitted to DySPAN’07 Feasibility of Dynamic Spectrum Access in Underutilized Television Bands

Abstract — This paper presents the preliminary results from a feasibility study regarding the operation of secondary spectrum users within unused television spectrum. Television spectrum is known within the wireless communications community as being underutilized, making it a prime candidate for dynamic spectrum access. Nevertheless, the quality of this spectrum for enabling secondary transmissions has never been assessed. Two unique scenarios are examined:(i) the possibility of unlicensed devices interfering with digital TV reception, and (ii) the possibility of secondary users experiencing interference when operating within close proximity to television towers. With respect to the former, we investigate the critical operating parameters for developing the technical rules for device operation in bands adjacent to a digital television transmission. Regarding the latter, we examine, via measurement campaign, how non-ideal transmission properties of television broadcasts, including intermodulation and saturation effects, can potentially impair the performance of secondary transmissions. Index Terms—Digital TV, spectrum measurements, spectrum white space I